Proceedings of the 148th Meeting of the Society of British Neurological Surgeons

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Surgical management of ruptured aneurysms unsuitable for endovascular intervention: an emerging challenge following ISAT

K. A. Choudhari, M. S. Ramachandran & M. O. McCarron (Regional Neurosciences Unit, Royal Victoria Hospital, Belfast, and Department of Neurology, Altnagalvin Area Hospital, Londonderry, UK)

Objective: Since ISAT, most ruptured aneurysms are primarily treated by endovascular means. Not all cases are, however, suitable. The authors present a series of 39 consecutive cases of aneurysmal haemorrhage treated by surgery where the aneurysms were deemed unsuitable for endovascular treatment by expert neuro-interventionalists. The aims were to:

• analyse clinical outcome of cases considered unsuitable for endovascular intervention;

• outline technical difficulties in surgical management;

• discuss operating time, training, sub-specialization in the context of recent changes in the practice.

Design: Three-hundred-and-twenty-one cases of aneurysmal subarachnoid haemorrhage were treated over three consecutive postISAT years (Aug 02 – Jul 05). Thirty-nine patients with 46 aneurysms were treated surgically as their aneurysms were deemed unsuitable for endovascular treatment either due to unfavourable morphology of the aneurysm and/or aberration in the intracranial vasculature.

Outcome measures: The clinical outcomes were audited at 6 and 24 weeks by the Glasgow Outcome Score and the Modified Rankin Scale, validated independently. Secondary factors such as surgical time, number of clips, performance by trainees, etc., were studied.

Results: Favourable outcome (MRS 0 – 2) in 90% of good grade (WFNS Grade I – II) and 42% poor grade (WFNS Grade III – V) patients. However, surgical time increased by 55% and the proportion of cases operated by trainees fell to 3% compared with 33% in the pre-ISAT era.

Conclusions: Ruptured aneurysms unsuitable for endovascular treatment are also difficult to treat surgically. Most cases are unsuitable for trainees. However, with neurovascular sub-specialization and consultant-delivered service, good surgical outcome can be accomplished in a higher percentage of patients than portrayed by ISAT.

Is treatment of poor-grade aneurysmal subarachnoid haemorrhage patients justified?

G. E. Pickett, L. D. Laitt, R. Protheroe & J. R. S. Leggate (Greater Manchester Neurosciences Unit, Hope Hospital, Salford UK)

Objective: High rates of death and disability among patients presenting with WFNS grade of 4 or 5 following subarachnoid haemorrhage (SAH) have led some to question the clinical benefit or cost-effectiveness of treatment. We audited outcomes over a 2-year period to assess rates of good recovery and try to identify predictors of outcome.

Design: Retrospective review of patients identified through computerized ICU database. Hospital notes were reviewed to obtain demographic and clinical information including WFNS grades, length of stay, investigations and methods of treatment, and clinical outcomes.

Subjects: All patients admitted to ICU with diagnoses of ‘subarachnoid bleeding’ and/or ‘intracranial aneurysm’ were reviewed. Patients admitted to ICU during their hospital stay but after aneurysm treatment were excluded from further analysis.

Outcome measures: Mortality, Glasgow Outcome Score (GOS) at hospital discharge and 1 year.

Results: After excluding patients with SAH due to trauma or AVM, and electively treated aneurysms, we identified 113 cases of presumed aneurysmal SAH, of which 70 entered ICU prior to treatment. Half of the patients left hospital alive, with 88% of survivors making a good recovery (GOS 4 – 5) at 1 year. Thus, 40% of those referred in poor grade recovered to independent function, and few survived with permanent severe disability. Recovery was not significantly associated with initial WFNS grade; patients who were poor-grade from ictus were as likely to have a good outcome as patients who were initially good-grade, but deteriorated early.

Conclusions: Patients presenting in poor-grade following SAH have a reasonable chance of meaningful neurological recovery and aggressive therapy is justified.

Subarachnoid haemorrhage—the 5-year experience of a ‘smaller’ neurosurgical unit

E. Campbell & D. Mowle (Ninewells Hospital, Dundee UK)

Objective: To document the investigation, management and outcome of all patients, following a spontaneous subarachnoid haemorrhage, admitted to the unit, between 1 September 2000 and 31 August 2005.

Design: Retrospective analysis of case notes.

Subjects: All patients admitted to the regional neurosurgical unit following a spontaneous subarachnoid haemorrhage, diagnosed either by computer tomography or lumbar puncture.

Outcome measures: Mortality, Glasgow Outcome Score.

Results: One-hundred-and-seventy-eight patients were included in the study, 148 patients were investigated to identify an underlying cause of their haemorrhage. One-hundred-and-six patients were identified with an aneurysm, 93 patients underwent an intervention to secure their aneurysm; surgical clipping 52 patients, endovascular coiling 41 patients. Mean time from onset of symptoms to securing of aneurysm was increased in patients who underwent endovascular coiling, but their overall stay in hospital was reduced, compared with patients who had their aneurysm clipped. One patient who underwent endovascular coiling died (2.4%), seven patients who underwent surgical clipping died (13.5%). A total of 87.2% of patients who underwent endovascular coiling had moderate disability-good recovery at 8-week outpatient review, compared with 66.7% of patients who underwent surgical clipping.

Conclusion: The majority of patients who present with an aneurysmal subarachnoid haemorrhage now undergo endovascular coiling. It is this unit's experience that although the mean time to secure the aneurysm is increased, there is no detrimental effect on the patient's final outcome.

Spinal dural arterio-venous fistula: clinical features and results in 29 cases

S. Dambatta, N. V. Mathad, O. C. E. Sparrow & J. Millar (Wessex Neurological Centre, Southampton, UK)

Objective: To assess the results of treatment for spinal dural arteriovenous fistulae.

Design: Retrospective analysis of case notes and radiological investigations.

Subjects: Twenty-nine consecutive patients with spinal dural arteriovenous fistulae treated from 1995 to 2005.

Outcome measures: Neurological status and radiological evidence of obliteration of fistula.

Results: An even distribution from 4th to 8th decade (range 12 – 87 years). Twenty-one (72%) patients were male. The commonest location was at thoracic region (55%). Presenting symptoms were pain (58%), other sensory symptoms (79%), motor symptoms (75%) and sphincter disturbances in 62%. All patients had MRI, and spinal angiography was done in 93%. Fifteen patients had surgical disconnection, with a further six patients undergoing surgery following a failed endovascular procedure. Of 21 operated patients, 13 improved clinically and in 15 patients there was radiological evidence of obliteration of the fistula. Five patients had successful endovascular obliteration of fistula. In total, 18 patients were clinically better and 20 patients had radiological evidence of cure.

Conclusions: Spinal dural arteriovenous fistula is rare, but an important treatable cause of chronic progressive myelopathy.

Long-term outcome after posterior cervical foraminotomy

H. El-Maghraby, R. S. Maurice-Williams & R. Bradford (Department of Neurosurgery, Royal Free Hospital, London, UK)

Objective: To assess the long-term outcome of posterior cervical foraminotomy.

Design: Retrospective chart review.

Subjects: Two-hundred-and-eighty patients underwent posterior cervical foraminotomy between 1983 and 2003. Long-term follow-up was available in 242 patients.

Outcome measures: Modification of the criteria of Odom et al. and the requirement of further surgical intervention.

Results: Three-hundred-and-sixty-two posterior cervical foraminotomies were performed in 242 patients with foraminal stenosis compressive radiculopathy. Single level in 141 patients (58.4%), bilateral in 40 patients (16.5%), two levels in 42 patients (17.5%) and three or more in 19 patients (7.6%). Anatomical levels were C4 (1.3%), C5 (10.8%), C6 (44%), C7 (40%) and C8 (3.9%). Follow-up range was 18 – 240 months postsurgery with a mean of 90 months (7.5 years). Ninety-six per cent of patients reported excellent or good results while 4% were not improved. No patient was rendered worse following the procedure. Further surgery for recurrent root symptoms was required in 14 patients (5.7%), four redo foraminotomies and 10 anterior cervical decompression at same level. Surgery for new symptoms was in 20 patients (8.3%), eight new level foraminotomy, three posterior cervical laminectomy for cervical spondylosis and nine anterior cervical decompression. All the 34 patients who required surgery, there was no radiological evidence of spinal instability.

Conclusion: Posterior cervical foraminotomy resolves compressive radiculopathy and does not require sacrifice of a functioning motion unit.

Porous coated motion (PCM) artificial cervical disc replacement

E. McKintosh, R. Tiruchelvarayan, R. W. Gullan, F. Wuytack & J. Wells (King's College Hospital, London, UK)

Objective: Presenting the early clinical results of PCM artificial cervical disc replacement for motion preservation.

Design: A prospective study involving patients presenting with myelopathic or radiculopathic symptoms who underwent anterior cervical discectomy PCM arthroplasties. The period of study was between March to October 2005.

Subjects: A total of 20 PCM cervical disc replacements were performed in 13 patients. Minimum follow-up period was 6 months.

Outcome measures: Range of motion, operative complications.

Results: Six were single level and seven were double level replacements. Ten patients were radiculopathic, three myelopathic. Average age was 46 years old (range: 33 – 53 years), seven male patients and six females. Levels included: nine C6 – 7, seven C5 – 6, three C4 – 5 and one C3 – 4. Average postoperative range of motion at 6 weeks was 2° (range: 1 – 5°) and there continued to be good motion at 6 months follow-up. There were no complications of wound infection or device related issues.

Conclusions: Early results show the PCM cervical disc replacement to be safe, beneficial for motion preservation. It can be inserted simply with minimal lengthening of operating time. Larger scale PCM trials in other centres will also be discussed.

Does pre-existing degenerative spondylolisthesis affect the outcome of simple laminectomy for lumbar canal stenosis?

M. J. Wiliby & R. J. C. Laing (Academic Neurosurgery Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, Cambridge, UK)

Objective: To investigate the effect of pre-existing degenerative mal-alignment on outcome in a prospective cohort of patients undergoing lumbar decompression for lumbar canal stenosis without stabilization.

Design: Prospective cohort of patients with lumbar canal stenosis undergoing simple laminectomy. Outcome data was both objective (SF-36, Roland back pain score, visual analogue scores) and subjective (patient satisfaction). Data was collected preoperatively, 3 months postoperatively and at long-term follow-up (median length of follow up 24 months). The presence of malalignment was assessed on preoperative MRI scans. Outcome scores have been analysed and in particular the effect of pre-existing spondylolisthesis at the operated level has been assessed. Statistical significance (Wilcoxon matched pair ranks and one way ANOVA) was evaluated using the SPSS statistical package.

Subjects: One hundred patients (57 men, 43 women). Average age 68 years, interquartile range 60 – 77 years. Twenty-three patients with preoperative radiological mal-alignment (at least spondylolisthesis grade I).

Outcome measures: SF-36, Roland back pain score and visual analogue back and leg pain scores.

Results: Approximately 80% of patients reported improved SF-36 physical functioning scores compared with preoperatively. The improvement in scores was significant for all visual analogue, physical arms of the SF-36 (except general health) and Roland back pain scores (p < 0.01) at both 3 months and 2 years following surgery compared with preoperative scores. All outcome measures showed further significant improvements at 2 years compared with 3 months (p < 0.01). The presence of preoperative degenerative mal-alignment was not associated with worse outcome at any of the postoperative assessment time-points.

Conclusions: Lumbar canal stenosis is a condition frequently treated by neurosurgeons. Our data supports the view that patients with pre-existing mal-alignment do not require stabilization in order to attain outcome scores comparable to patients with normal alignment.

Cervifix® system for posterior cervical spine stabilization: instrumentation failure analysis

C. H. Lee, G. Hill, H. Alkhateeb, F. Prada & A. T. H. Casey (Spinal Surgical Unit, Royal National Orthopaedic Hospital, Stanmore, UK)

Objective: To assess the efficacy of CerviFix® modular screw & rod system (Synthes, USA).

Design: A 5-year retrospective review of patients with 2-year follow up.

Subjects: Patients who underwent posterior cervical stabilization.

Outcome measures: Surgical complication, instrumentation failure, Kaplan – Meier Analysis.

Results: Eighty-seven patients in total with mean age 53.2 years (18 – 88 years). Indications for surgery included congenital deformity (9 patients), trauma (32), inflammatory disorders (25), primary and secondary neoplasia (three and nine, respectively), degenerative deformity (seven) and revision of previous laminectomy (two). There was one death related to surgery. Nineteen patients developed surgical complications. There were 11 instrumentation failures (12.6%), occurring early in the postoperative period (5.7%), at 6 months (3.4%) and at 1 year follow-up (4.5%). Seven cases required further surgery. Three neurological complications and a single vascular injury that was managed conservatively. The remaining patients developed wound complications.

Conclusions: This is the largest study for posterior cervical fixation using the CerviFix® system to date. Incidence of instrumentation failure has not been emphasized in other literature.

Bryan cervical disc arthroplasty; 12-month follow-up

A. Amit & N. L. Doward (Royal Free Hospital, London, UK)

Objective: Cervical arthroplasty is a novel surgical treatment modality for cervical spondylosis. We present the results of a 12-month clinical follow-up study based on Health Status Questionnaire, Clinical and radiological range of motion follow-up after Bryan disc prosthesis.

Design: Prospective observational clinical study.

Subjects: Twenty-five patients were followed up after a single level anterior decompression and Bryan cervical disc prosthesis at scheduled follow-up periods of 6 weeks and 6 months and 12 months. There were 16 men and nine women, in the age range of 39 – 79 with an average age of 51 years. Nineteen patients had radiculopathic and six had myelopathic symptoms preoperatively.

Outcome measures: Prospective assessment using six outcome measures, (1) visual analogue scale (VAS), (2) short form (SF-36), (3) myelopathy disability index (MDI), (4) neck disability index (NDI), (5) Odom's criteria and (6) Cobbs angle was done both preoperatively, at 6 months and 12 months postoperatively.

Results: The analysis of the clinical data revealed a statistically significant (p < 0.001) improvement in the visual analogue scale, both the physical and the mental components of the SF36 v2 scores, the neck disability index and the myelopathic disability index at the end of 12 months. In all cases sagittal alignment and motion at the level of arthroplasty were maintained.

Conclusions: These results demonstrate that outcomes after a Bryan Cervical Disc Prosthesis performed on appropriately selected patients is a reliable surgical procedure for the management of cervical radiculopathy and myelopathy at the end of 12 months.

Protein S100b, brain natriuretic peptide and troponin I in subarachnoid haemorrhage

I. Liaquat, A. Bahl, R. A. Sherwood & A. Strong (Department of Neurosurgery, King's College Hospital, London, UK)

Objective: Subarachnoid haemorrhage (SAH) may be associated with myocardial damage. Increased S100B in plasma has been reported after SAH. Brain natriuretic peptide (BNP) and troponin I (TnI) are plasma indicators of myocardial dysfunction or damage. The aim of the study was to determine if plasma concentrations of s100B, BNP and TnI were elevated following SAH and related to prognosis.

Design: Patients with SAH who presented within 24 h of the ictus were recruited. Blood was taken for BNP, TnI and S100B at presentation, 48 h and 7 days. Patients were sub grouped by Hunt & Hess grade at presentation.

Subjects: Twenty patients were recruited and sub grouped to group A (Grade 1, n = 8) and group B (Grade 2, n = 12).

Outcome measures: BNP, TnI and S100B were compared in the two groups of patients. (Values are expressed as the median.)

Results: S100B (normal <0.2 μg/l) was raised at presentation in group B patients (0.54 μg/l), but not group A patients (0.1 μg/l), p < 0.0001 by Mann – Whitney analysis. A cut-off for S100B of 0.15 μg/l provided a sensitivity and specificity of 100% for prediction of poor prognosis. TnI (normal < 0.2 μg/l) was raised in 50% of group B patients and 12.5% of group A patients; however, this difference did not reach statistical significance, p = 0.22. BNP was correlated by Spearman rank analysis to TnI (r = 0.65, p < 0.0003) and to S100B (r = 0.35, p = 0.04).

Conclusions: S100B concentrations correlate with the clinical grade of SAH and is a predictor of prognosis in patients with SAH.

Bilirubin in CSF of CT negative SAH patients strongly suggests presence of a structural abnormality

M. S. Miah, N. A. Farooqi, D. G. Quigley, A. R. Brodbelt & M. Javadpour (Walton Centre for Neurology and Neurosurgery, Liverpool, UK)

Objective: To correlate biochemical findings of CSF in patients with CT negative subarachanoid haemorrhage (SAH).

Design: Retrospective case review and CSF analysis.

Subjects: Between January 2004 and December 2005, 20 patients presented with CT negative, Lumbar Puncture (LP) positive subarachanoid haemorrhage.

Outcome measures: Presence of bilirubin in CSF samples and correlation with history and angiographic findings.

Results: Twenty patients presented with history suggestive of SAH but a normal CT. All patients underwent LP at the referring hospital and samples were sent for spectrophotometric analysis. All patients had CT angiogram and digital subtraction angiography. An aneurysm/s was identified in 11 cases, nine had no abnormality. Bilirubin was present in all samples with structural abnormality. In the nine patients with no angiographic abnormality only two had bilirubin in their CSF samples. One had LP attempts four times.

Conclusions: In patients presenting with a good history of SAH who have no blood on their CT scan, the presence of bilirubin in the CSF is a powerful indicator of a vascular abnormality and necessitates further investigations.

Magnetic resonance angiography and constructive interference in steady state-three-dimensional Fourier transformation. Magnetic resonance imaging in patients with hemifacial spasm. Comparison with surgical findings in 42 cases

A. Tarnaris, S. A. Renowden & H. B. Coakham (Department of Neurosurgery and Department of Neuroradiology, Frenchay Hospital, Bristol, UK)

Objective: Preoperative imaging of the neurovascular relationships at the root exit zone of facial is important to exclude a non-vascular cause or identify dolichoectatic vessels that might influence the surgical approach in MVD for HFS. MRA is now accepted as a superior method to conventional MR imaging. Recent studies have advocated the combined use of MRA and routine MR for the preoperative assessment of patients with HFS. More recently, newer MR sequences, such as Constructive Interference in Steady State (CISS)—Three-dimensional Fourier Transformation (3DFT) have been suggested as alternatives. The current study was designed to compare the specificity and sensitivity of gadolinium-enhanced 3D fast inflow with steady state precession (FISP) MRA with CISS.

Design: Retrospective review of imaging. Single blind assessment by one of the co-authors (SAR).

Subjects: Forty-two patients that had microvascular decompression for hemifacial spasm. The study population spans 19 years (1985 – 2004).

Outcome measures: Identification of neurovascular contact.

Results: Neurovascular contact could be seen in 12/42 (28.6%) in routine T2 axial scans, in 20/33 (60.6%) in high resolution T2W, in 15/31 (48.4%) in the case of MRA, and in all cases (11/11) with the CISS sequence. This study demonstrated 60% sensitivity and 100% specificity for MRA with gadolinium enhancement, whereas the CISS sequence can achieve a sensitivity of 90.9% in correctly demonstrating neurovascular compression in HFS. Positive Predictive Value was 100 and 100%, Negative Predictive Value was 7.69% and 100%, and accuracy of the two methods was 61.3 and 90.9% for MRA and CISS, respectively.

Conclusions: The CISS sequence is more sensitive in identifying neurovascular compression when compared with MRA. Due to cost and time implications we suggest that MR-CISS imaging can be the single sequence of choice in the detailed preoperative MR assessment of hemifacial spasm.

Bus-related head injuries in London: identification of six patterns of trauma

A. K. Demetriades, J. Grieve, P. Minhas, M. C. Papadopoulos & M. C. Gavalas (Atkinson Morley Wing, St George's Hospital NHS Trust, National Hospital for Neurology and Neurosurgery, Queen Square & Department of Accident and Emergency Medicine, University College London Hospital, London, UK)

Objective: To identify the extent and patterns of bus-related head injuries affecting bus-passengers and pedestrians in London.

Design: A 1-year prospective study in a central London Accident and Emergency Department.

Subjects: All patients presenting with a head injury relating to a bus.

Outcome measures: Mechanism of injury; type of head trauma; associated injuries.

Results: One-hundred-and-thirty-five consecutive cases were recorded. While the majority were minor head injuries, a considerable proportion (32%) were severe needing hospitalization for neurosurgery and/or neuro-intensive care. Six patterns were identified: First, the direct hit of a pedestrian by a vehicle in motion both at a bus-stop and at >30 mph situations; The second was observed mainly in the elderly who suffered a fall in the bus during deceleration/acceleration – the passenger trying to find a seat or get up from one at a bus top. The third involved mainly younger passengers who tried to jump onto the back of a moving double-decker bus and misjudged speed or distance; The fourth affected again double-decker passengers who when crowded were standing near the open-rear exit holding the pole, but falling backwards and off the bus at acceleration or turning episodes. One such was near fatal when the patient hit his head onto a kerb. The fifth mechanism of injury involved pedestrians at the edge of the pavement whose heads were clipped by the wing-mirror of a single level bus. This injury type was associated with an acute extradural haematoma and scalp degloving injuries; The sixth was seen with tourists who are used to right hand driving who see no hazard from the left and ignore traffic from the right.

We dealt with serious trauma including acute subdural and extradural haematomata, brain contusions, traumatic subarachnoid haemorrhage and diffuse axonal injury. Elderly people were more prone to an associated craniocervical injury in patterns 2 and 4, whereas in the sixth category the average presenting GCS was much lower associated with an increased severity of injury. Recovery was variable according to age, GCS on admission and severity of injury.

Conclusions: The implications of these observations, clinical, civic and preventative, are discussed.

Glioblastoma multiforme 80 years after Harvey Cushing, are results any better?

V. Petrik, A. Loosemore, M. C. Papadopoulos & B. A. Bell (St George's University of London, UK)

Objective: To evaluate the outcome of patients with glioblastoma multiforme (GBM) and compare it with Harvey Cushing's 1924 series.

Design: Retrospective study.

Subjects: One-hundred-and-forty-six consecutive patients (June 2002 – November 2004) with a histologically confirmed diagnosis of GBM, 55 females and 91 males, age (mean ± standard deviation) 58.6 ± 11.4 and 59.5 ± 11.0, respectively.

Outcome measures: Effect of age, presenting Karnofsky score, type of surgery, radiotherapy and chemotherapy on outcome assessed by Kaplan – Meier survival analysis and Cox proportional hazard model.

Results: Maximum survival in our patients was 154 weeks, mean 40 and median 27 weeks. The significant factors in Cox multivariate analysis were age (p = 0.001), presenting Karnofsky score (p = 0.008), extent of surgery (biopsy, partial or total excision; p < 0.001), radiotherapy (p = 0.017) and chemotherapy (p = 0.006).

Conclusions: In Cushing's series of 77 patients, five survived more than 3 years and mean survival was 52 weeks. This is longer than mean survival in our partial excision group (34 weeks), but shorter than in our total excision group (85 weeks). Cushing's results are most likely to be the result of his radical surgical approach that is supported by our data.

Brain stem death and sperm retrieval: case study and discussion of the ethical and legal issues

L. Zrinzo, M. Zrinzo, O. Jeelani, S. Chandrasekaran & J. Pollock (Oldchurch Hospital, Romford, Essex, and Professional Education - Law School, London, UK)

Objective: Neurosurgeons are frequently involved in issues surrounding brain death. Sensitive ethical and legal considerations are often encountered in such circumstances.

Design: The authors present an unusual request: relatives of a patient in irreversible coma asking for sperm retrieval prior to brain stem tests being performed.

Subject: A 35-year-old male was admitted with Grade 5 subarachnoid haemorrhage. Despite optimal medical and surgical management, generalized vasospasm resulted in widespread cortical infarction. The patient's relatives were informed of the poor prognosis and plan for brain stem testing. During the discussion, the patient's wife enquired whether sperm retrieval was possible.

Discussion: The ethical and legal implications of such a request are complex and not immediately intuitive. The authors share their experience of obtaining advice on this issue from various regulatory and medical authorities. The medicolegal literature is reviewed and legal positions are explained.

Conclusions: Neurosurgeons may increasingly have to deal with next-of-kin requesting sperm retrieval from moribund or brain dead patients and should be aware of the ethical and legal implications. These important issues, which have not previously been discussed in the neurosurgical literature, are reviewed in this presentation.

Near infrared spectroscopy can detect reduced cerebral oxygen utilization during hypoxaemia in healthy volunteers

M. Tisdall, I. Tachtsidis, C. E. Elwell, N. Kitchen & M. Smith (National Hospital for Neurology and Neurosurgery, Queen Square, London, UK)

Objective: To use near infrared spectroscopy to measure changes in the cerebral concentration of oxidized cytochrome oxidase (Δ[oxCCO]) during hypoxaemia in healthy volunteers.

Design: Broadband near infrared spectrometer optodes were placed on the forehead. Non-invasive blood pressure, arterial oxygen saturation (SaO₂) and transcranial Doppler probes were attached. After initial baseline recording, the inspired oxygen concentration was reduced by addition of nitrogen to induce a fall in SaO₂ to 80%, and then returned to baseline. This cycle was repeated three times. End tidal partial pressure of carbon dioxide (EtCO₂) was continuously fed back to subjects throughout the study and they were instructed to maintain normocapnoea.

Subjects: Twelve healthy volunteers (nine male, three female, median age 30.5 years).

Outcome measures: Measured changes in Δ[oxCCO], SaO₂, middle cerebral artery blood flow velocity and estimated change in oxygen delivery.

Results: Results are presented as median and interquartile range. At the nadir of hypoxaemia, the reduction in SaO₂ was 15.9 (13.9 – 17.3)% and this corresponded with a reduction in estimated oxygen delivery of 6 (3 – 10)%. The reduction in measured Δ[oxCCO] was 0.27(0.06 – 0.28) μM. At this point, changes in SaO₂, estimated oxygen delivery and Δ[oxCCO] values were all statistically significant (p < 0.05 for change from baseline assessed using non-parametric ANOVA with post hoc comparisons). There were no significant changes in EtCO₂ or mean blood pressure during the study.

Conclusions: Near infrared spectroscopy can detect changes in cerebral concentration of oxidized cytochrome oxidase during hypoxaemia and this measurement has potential as a clinical tool to assess changes in cerebral cellular redox state.

Efficacy of fluoroscopically guided cervical nerve root block

M. Akula, B. Razzaq, D. O'Brien Mathew, D. Taylor & R. Bartlett (Department of Neurosurgery, Hull Royal Infirmary, Hull, UK)

Objective: To assess the long-term effectiveness of fluoroscopically guided, therapeutic selective nerve root block as a non-surgical treatment approach in relieving cervical radicular pain.

Design and subjects: This was a retrospective study of nineteen consecutive patients who had undergone cervical nerve root blocks over a period of 18 months, at a regional neurosurgery referral centre. Two of these patients underwent a second procedure; therefore, the number of total nerve root blocks was 21. Data regarding age, sex and diagnosis were obtained from medical records. MR reports formed the basis for imaging findings which were divided into three categories based on the location of nerve root compression: foraminal, central or both.

Outcome measures: Patients were contacted through telephone and post in order to obtain information about pain relief. Pain relief was measured by using a 100-point Visual Analogue Scale. Four points in time were chosen in order to determine the time course of pain relief, i.e. before procedure, at 2 weeks, at 2 months and at 6 months following the procedure.

Results: The mean VAS pain score before the procedure was 79.3. At 2 weeks the mean VAS score had decreased to 45, VAS was 52 at 2 months and 73 at 6 months. Mean VAS scores were broken up into three categories to indicate the level of pain relief. These categories were: (1) VAS decrease of less than 20 points indicating no relief (nine patients, 43%); (2) VAS decrease 20-40 points i.e. moderate relief (six patients, 29%); (3) VAS decrease of greater than 40 points, i.e. significant relief (six patients, 29%).

Conclusions: Although approximately half the patients obtained good pain relief from the initial procedure; however, pain relief did not last more than 2 months in most of these patients. Therefore, this procedure may not be feasible for long-lasting relief from cervical radicular pain.

A brief history of functional neurosurgery for psychiatric disorders

J. A. G. Miller & K. Ashkan (Unit of Functional Neurosurgery, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, UK)

Objective: To provide a comprehensive review of the history of functional neurosurgery for psychiatric conditions.

Design: Medline literature review of articles containing any combination of Keywords: psychosurgery, functional neurosurgery, lesioning, deep brain stimulation, psychiatric, depression and obsessive-compulsive disorder.

Outcomes: Neurosurgery for psychiatric conditions such as obsessive-compulsive disorder and depression has had a long and stormy history from its beginnings in the Stone Age to its meteoric peak in the early half of the 20th century, fuelled by the growing realization of the complex connection between the brain and behaviour particularly in the latter half of the 19th century. The theory was put into practice by the pioneering surgeries of Burkhardt, Moniz and Freeman who became the founders of psychosurgery and whose names became synonymous with frontal lobotomies they performed. Parallel developments in stereotactic surgery allowed placement of more precise lesions, such as cingulotomies or capsulotomies. Such procedures although initially performed in staggering numbers, were later criticized for being destructive, irreversible and a means of mind control. This ethical backlash together with pharmacological advances in the 1960s and 1970s led to a progressive decrease in the popularity of psychosurgery. In recent decades, however, better knowledge of the limitations of psychoactive drugs, advances in surgical and imaging techniques as well as improved peri-operative care of patients have resulted in a resurgence of interest in psychosurgery. Deep brain stimulation, because of its non-destructive, reversible and adjustable nature, has emerged as a particularly attractive modality both for its safety and potential social acceptability. Its effectiveness in the treatment of intractable psychiatric illness has recently been reported.

Conclusion: Functional neurosurgery for psychiatric disorders has had a tumultuous past, but recent developments in surgical techniques may herald an exciting future.

Exact location of active DBS contact within target area predicts degree of clinical improvement in Parkinson's disease and dystonia

L. Zrinzo, S. Tisch, K. Ashkan, P. Limousin & M. Hariz (Essex Neuroscience Centre, Oldchurch Hospital, Romford & Unit of Functional Neurosurgery, Queen Square, London, UK)

Objective: The ideal location within the target areas for chronic high frequency electrical stimulation in the treatment of movement disorders is still debated.

Subjects: Twenty-five electrodes were implanted in the subthalamic area of 13 consecutive patients with PD. Twenty-two electrodes were implanted in the posteroventral globus pallidus pars interna (GPi) in 11 consecutive patients with primary generalized dystonia.

Design: Neurologists blinded to contact location assessed which contacts provided optimal clinical effect. Hemibody functional scores were recorded preoperatively and again during optimal stimulation 6 – 12 months postsurgery. Hemibody functional scores were derived from the Unified-Parkinson's-Disease-Rating-Score (UPDRS) and Burke – Fahn – Marsden (BFM) score for PD and dystonia patients, respectively. The exact location of the active contact in relation to the patient's own anatomy was independently derived from pre and postoperative stereotactic images.

Results: Electrode contacts clustered within anatomical groups that differed significantly in functional outcome (p < 0.05). For PD patients, contacts in the dorsal subthalamic nucleus were associated with a mean improvement of 64% in contralateral hemibody functional scores. An excellent outcome (>70% improvement) was obtained in 8/16 sides. For contacts outside this region, the mean improvement was 45% with 0/9 sides obtaining an excellent outcome. For dystonia patients, superior outcome in hemibody BFM score (>80% improvement) was significantly more likely when active contacts were in the most posteroventral part of the GPi (p < 0.05).

Conclusions: The exact anatomical location of electrode contact placement has a significant bearing on functional outcome in deep brain stimulation for PD and generalized dystonia.

The XSTOP® registry. A mechanism for routine collection of international prospective clinical data from a variety of clinical scenarios

J. Timothy¹, P. Simons², D. Werner³, P. Krause⁴, P. Marx⁵, G. Godde⁶ & A. Reinhard⁷ (¹Leeds General Infirmary, Leeds, UK, ²Media Park klinik, Media Park 3, 50670, Cologne, Germany, ³Arkade Privatklinik, Niederschmalkalden, Germany, ⁴Orthopädische Schmerztherapie, Munich, Germany, ⁵Westend Krankenhaus, Berlin, Germany, ⁶Gemeinschaftspraxis Konigsallee, Düsseldorf, Germany, and ⁷Oberlinhaus, Potsdam, Germany)

Objectives: A registry has been piloted by members of this group as testing for release in 2006. The idea is to enable surgeons, using the XStop® to collect data for Clinical Governance, personal interest or in a study potentially resulting in publications.

Design: The Internet Based System is password protected and encrypted. Preoperative demography, etc., surgical details and complications, plus relevant patient and surgeon administered outcomes questionnaires pre- and postoperatively (6 – 12 weeks, 6, 12, 24 and 60 months) are collected. Statistical analysis planned when 100 patients have a minimum 12 months follow-up.

Subjects: Suitable, consented patients, with LSS receiving the XStop®, or alternative in a comparative study.

Outcome measures: Data collected for the ZCQ and SF36 questionnaires, and plans exist to collect ODI and other validated scores.

Results: Two-hundred-and-twelve patients (mean age 68.4 years and 46% male) with an average of 11.3 months follow-up (range: 6 weeks to 24 months) and 80% compliance at 12 months. Significant improvement in ZCQ Symptom Severity and Physical Function seen in 82 and 77% patients at 12 months. Overall, 80% of the patients were clinically successful at this time. Similar improvements were seen with the SF36. Complications in <1% patients.

Conclusions: Free availability of a registry with analysis and reporting enables surgeons to compare their experience with other groups and published series. It will facilitate more publications something that is needed according to the recent Cochrane Review. Interestingly, this review cited the Zucherman et al. study as one of the few quality papers available.

Outcomes following surgical treatment of neuralgias of the glossopharyngeal and vagal nerves

S. Khan & H. B. Coakham (Department of Neurosurgery, Institute of Clinical Neurosciences, Frenchay Hospital, Bristol, UK)

Objective: Most of the case series following this treatment are from centres in North America. We have reviewed our experience with the surgical treatment of this condition and hope to prove its safety and efficacy in a consecutive series of 12 patients.

Design: Patient notes were reviewed to obtain demographic information, presenting history, surgical history and early results. All 12 patients were then contacted by telephone for long-term results and complications.

Results: At the time of surgery, four patients were found to have vascular compression of the vagal and glossopharyngeal nerve roots. Of these patients, the PICA was the compressing vessel in three cases and the VA in one. In the remaining eight patients where no vascular compression was identified the glossopharyngeal and first two rootlets of the vagal nerve were sectioned. Follow-up of the patients was at a mean duration of 5 years and 4 month. In the patients who had undergone microvascular decompression there was a 100% immediate and long-term cure rate. In the eight patients who had undergone nerve root sectioning six experienced full resolution of pain both in the immediate postoperative period and on long term follow up. The other two patients experienced 50 and 75% resolution of pain, respectively. In total two patient experienced a temporary hoarse voice, which completely recovered.

Conclusion: Surgical intervention is a safe and effective treatment of glossopharyngeal neuralgia.

The use of continuous intrathecal baclofen infusion (CIBI) in children with dystonia

K. Woon, M. Cartmill & M. Vloeberghs (Department of Neurosurgery, Queens Medical Centre, Nottingham, UK)

Objective: Intrathecal baclofen has been used for the treatment of spasticity with good results. More recently, intrathecal baclofen is shown to be more effective when dystonia was associated with spasticity and pain. We aim to share our experiences on the use of continuous intrathecal baclofen infusion (CIBI) pumps in paediatric patients with dystonia.

Design: This is a retrospective analysis from a single unit of paediatric patients who had a CIBI pump inserted from October 1998 to October 2005. Their age ranged from ten to eighteen years. CIBI pumps were implanted in seven patients, of which three were boys and four were girls. Two patients had secondary dystonia from cerebral palsy. Five patients had primary dystonia, two patients had idiopathic dystonia, one of which had previous treatment for deep brain stimulation for his dystonia. One patient had glutaric aciduria. Two patients had hallervorden spatz syndrome, one of which had previous treatment of deep brain stimulation for her dystonia.

Outcome measures: Parents or carers assessment of their child's ease of care, spasms and dystonic movement.

Results: All parents or carers reported improvement in the ease of care, severity of dystonia and especially the decline in spasms. One patient had a revision of the proximal catheter but remained well after.

Conclusion: CIBI pumps are particularly beneficial to paediatric patients with secondary dystonia although some improvement is noted in primary dystonia. CIBI pump insertion is safe and may also be used synergistically with other treatment for dystonia such as deep brain stimulation.

Spinal cord stimulation in the management of chronic pain syndrome—a 7-year experience

D. A. J. Rodrigues, F. Aziz, R. D. Strachan & S. Eldabe (Departments of Neurosurgery and Pain Management, James Cook University Hospital, Middlesbrough, UK)

Introduction: Spinal cord stimulation (SCS) is a valuable technique in the management of patients with intractable, chronic pain syndromes. At present there is limited evidence that SCS is effective. Patient selection has to be thorough in order to limit failure rates and guarantee a good outcome. Here, we review our experience with SCS over the last 7 years.

Methods and materials: Case records of patients who underwent SCS trial from January 1997 to December 2004 were analysed by an independent researcher.

Results: During this 7-year period 75 patients underwent 79 procedures. Trial implant was carried in 60 patients with 90% (54) achieving >50% reduction in their pain. The indications were FBSS (23), angina (15), neuropathic pain (14), CRPS I (12) and others 11 (CRPS II = 7, PVD = 4). The overall complication rate was 27.03%. Six patients had electrode failure (8.11%), while another six (8.11%) had migration of the electrode. Four (5.41%) patients had infection needing explantation and re-implantation of the electrodes. We had 86.7 and 89.3% follow-up at 6 months and 1 year, respectively. There was significant pain relief (>50%) in 53 (81.5%) patients at 6 months and 46 (68.7%) patients at 1 year.

Conclusions: Our data indicates that SCS can result in a significant long-term improvement in pain and quality of life among patients with chronic pain syndromes. Combined with a low complication rate, this audit also indicates that SCS represents a relatively safe and effective approach to long-term pain management.

The neurosurgical electronic logbook. A personal neurosurgical record from cradle to grave

S. Thomson & P. T. van Hille (On behalf of SBNS and SAC in Neurosurgery)

History: The E-logbook was developed for Urology and Orthopaedic trainees in 2001. In 2003 the Neurosurgical SAC and SBNS decided to join the project. Neurosurgical data collection started in September 2004. The logbook now supports consultant practice.

Current status (16^thNov 2005): 39,441 neurosurgical operations have been recorded, 212 users have joined the project (158 SpRs). Between all specialities >1,000,000 operations have been entered.

Logbook features: A place to store operative data. A place to store non-operative data (e.g. publications). Analysis tools. Reports to support appraisals and RITAs. Comparative peer group data. The logbook runs via the Internet, on hand-held and desktop computers. It can be accessed via the SBNS website, the basic features are free.

Logbook issues: The logbook has been ‘approved’ by the data protection officers in the Department of Health. The logbook is not designed to support comparisons of outcomes between consultants. The data is owned by the individual surgeon. Access to consolidated data is controlled by the SBNS.

Conclusion: The neurosurgical electronic logbook offers a place to record a neurosurgical log from cradle to grave.

The changing face of neurosurgery: a look 10 years apart

B. Arvin, A. Tarnaris & K. Ashkan (Department of Neurosurgery, National Hospital Neurology and Neurosurgery, Queen Square, London, UK)

Objective: To analyse the changing pattern of neurosurgical workload and the underlying factors in the recent decade.

Design: Retrospective examination of theatre log books, medical and pathological records of all patients operated in a major London neurosurgical unit in 2 years a decade apart (1994 and 2004).

Subjects: All patients operated in our unit in the years 1994 and 2004.

Outcome measures: The number and type of operations performed. These were categorized into emergency versus elective, and by the subspecialty such as functional neurosurgery, spinal surgery with and without instrumentation, vascular surgery, pituitary surgery and tumour surgery. The demographics of the patients were analysed.

Results: There were 2064 and 2232 operations recorded in years 1994 and 2004, respectively. The respective percentage of emergency surgeries in each year was 14% and 18%. The percentage of operations for vascular disease fell by 45% in this 10-year period. The total number of endovasular coiling rose by four-fold over the last 10 years. The total number of spinal decompressive procedures performed in the two study periods was comparable, although the number of those using instrumentation increased greatly by 50%. The number of functional operations increased by 30%. There was a clear shift away from lesioning surgery towards neuromodulation and deep brain stimulation. There was no significant difference between the number of patients in the hydrocephalous, tumour, pituitary and trauma surgery groups in the study periods although the demographics did differ.

Conclusion: There have been major changes in the practice of neurosurgery in the last decade. The most striking of these are in three subgroups. Functional neurosurgery, vascular and spinal surgery. Clipping of aneurysms or surgical treatment of arteriovenous malformations has dramatically decreased as a result of advances in endovascular techniques. Functional neurosurgery has re-emerged as a rapidly growing field with a definite shift towards neurostimulation. Spinal surgery has also changed in nature with a greater emphasis on instrumentation. Technological advances, patient and social expectations together with economical factors are likely to govern the practice and evolution of modern neurosurgery.

The forgotten side: in vivo assessment of inflammatory atheroma burden on the contralateral side to symptomatic carotid stenosis using high resolution USPIO-enhanced MR imaging

S. P. S. Howarth, T. Y. Tang, R. Trivedi, M. J. Graves, P. J. Kirkpatrick & J. H. Gillard (Addenbrooke's NHS Trust, Academic Department of Neurosurgery & Neuroradiology, Cambridge, UK)

Background: It is well known that vulnerable atheromatous plaque has a thin, fibrous cap and large lipid core with associated inflammation. This inflammation can be detected on magnetic resonance imaging using a contrast medium, Sinerem, an ultra small super-paramagnetic iron oxide (USPIO). Studies using USPIO to assess macrophage burden in symptomatic carotid disease have not yet analysed the contralateral asymptomatic side.

Methods: Twenty symptomatic patients underwent multi-sequence imaging at 1.5 Tesla pre- and 36 h post-USPIO infusion. Images were manually segmented into quadrants (CMR Tools) and signal change in each quadrant was calculated following USPIO. Patients had a mean symptomatic stenosis of 77% compared with 46% on their asymptomatic side as measured by angiography.

Results: Contralaterally there were 153 quadrants (54%) with a signal drop post-USPIO when compared with 201 quadrants (66%) on the symptomatic side (p < 0.05). Only one patient with USPIO signal drop on the symptomatic side showed no signal drop on the asymptomatic side. Mean signal drop per quadrant was similar on the asymptomatic compared with the symptomatic side (16.1 v. 16.7, p = 0.91).

Conclusions: This study indicates that atherosclerosis is a truly systemic disease. It suggests that investigation of the contralateral side in patients with symptomatic carotid stenosis can demonstrate inflammation in over 50% of plaques, despite a mean stenosis of only 46%. Thus inflammatory activity may be a significant risk factor in asymptomatic disease. Patients with symptomatic carotid disease having had an endarterectomy should have their contralateral carotid artery followed up and a low threshold for intervention may need to be adopted in this cohort.

The efficacy of antibiotic impregnated catheters in reducing shunt infections

C. Hayhurst, J. Grogan, P. Byrne, D. F. O'Brien, N. Buxton, C. L. Mallucci & P. L. May (Walton Centre for Neurology and Neurosurgery, Liverpool, UK)

Objective: Infection remains a major problem with CSF diversion procedures. Antibiotic impregnated shunt (AIS) catheters have been introduced to prevent infection, mainly in the early postoperative period when most infections occur. We evaluate the impact on reducing infection rates in clinical practice following the introduction of catheters impregnated with clindamycin and rifampicin (Bactiseal™, Codman).

Patients and methods: A retrospective analysis of all shunt procedures undertaken after the introduction of AIS systems. A total of 178 procedures were identified where a complete AIS system was implanted between October 2003 and December 2004. This includes 74 adults and 71 children, with follow-up of 9 months to 2 years. Procedures were classified as de novo, postexternal ventricular drainage and revision shunts.

Results: In the de novo shunt subgroup for both children and adults there were no infections. In the paediatric population (95 procedures) there were 12 infections in total, 7 (25%) postexternal ventricular drainage and five (11.6%) in revision cases. There were a total of three (3.61%) infections in adult shunt procedures, all in patients with prior external ventricular drains.

Conclusions: AIS catheters have reduced the number of CSF shunt infections overall, although the majority continue to occur in children. In the setting of de novo shunts the outcome is excellent, achieving a 0% infection rate. Gram positive organisms continue to predominate. The high risk of shunt infection after a period of external ventricular drainage calls for careful consideration of the indication for external ventricular drainage.

Antibiotic resistant infections with bactiseal catheters for VP shunts

D. Dasic, I. Liaquat, M. Murphy & S. Bassi (King's College Hospital, London, UK)

Introduction: Third ventriculostomy has found its niche in the treatment of hydrocephalus. Shunts, however, are still the commonest means by which hydrocephalus is treated. Despite the changes in valve and catheter technology shunt complications still continue to plague all neurosurgeons. Infection and blockage are still common, and a cause of great headache for the patient as well as the neurosurgeon. Antibiotic-laced catheters were proposed as a means by which to reduce shunt infection. We present our experience of 18 months of Bactiseal catheters including the new and novel complications related to antibiotic catheter use.

Aims: To assess the benefits and complications of the use of Bactoseal catheters for VP shunts.

Methods and materials: All consecutive patients who underwent a VP shunt form July 2004 to November 2005, under the care of one neurosurgeon were prospectively assessed.

Outcome measures: Diagnosis, scan findings, shunt used, preoperative antibiotics, ventricular and peritoneal catheter used, grade of surgeon involved in the operation, complications, treatment of complications.

Results: Fifty patients underwent VP shunting with bactiseal catheters, with a combination of NSC, strata and burr hole valves. The age range of the patients was from 1 week premature to 64 years old. Forty-two of the patients were paediatric. The diagnosis varied from postfossa tumours (11/50) to intraventricular haemorrhage, postmeningitic hydrocephalus and aqueduct stenosis. We discuss the overall complication rate and revision rate related to the specific cause of the hydrocephalus. We also report two cases of rifampicin resistant staphylococcus epidermidis in patients with Bactiseal catheters.

Discussion: In this culture of MRSA and ‘superbugs’ are we simply adding to the pool of resistant bacteria with the use of antibiotic laced catheters? We propose a wider study of the use of these and the newer silver laced catheters in shunted patients.

Outcome of CT guided perineural root injection in treatment of cervical and lumbar radiculopathy

H. El-Maghraby¹, S. Conway¹, A. Platt², A. Valentine², R. S. Maurice-Williams¹ & R. Bradford¹ (Departments of ¹Neurosurgery and ²Department of Neuroradiology, Royal Free Hospital, London, UK)

Objective: To assess the effectiveness of CT guided perineural root injection in treatment of cervical and lumbosacral radiculopathy.

Design: Retrospective chart review.

Subjects: 1168 procedures of CT guided transforaminal perineural root injections were enrolled between 2000 and 2004. Injection of 1 ml of 40 mg of triamcinolone acetonide and 1 ml of 0.5% of bupivacaine was given. Selection criteria for the first^t injection were pain persisting longer than 1 month, no objective neurological deficit and radiological evidence of root compression of benign nature. Selection criterion for repeated injections was acute exacerbation of the previously known radicular pain.

Outcome measures: Primary outcome measure was pain relief using visual analogue score at 6 weeks postinjection.

Results: 1168 procedures were performed in 392 patients. 211 patients (53.8%) with cervical radiculopathy and 181 patients (46.2%) with lumbosacral radiculopathy. 87.2% had three injections, 5.1% had two injections, 3% had one injection and 4.7% had more than three injections. Sixty-three patients (13%) had previous spinal surgery. There were no cases of root injury, six patients had the wrong level injected and the procedure was repeated at later date at the correct level and four patients had the procedure abandoned because of increased pain. Two hundred and sixteen patients (55%) reported pain reduction of at least 50% at the first injection. Three hundred and four patients (77.5%) reported pain reduction of at least 50% on subsequent injections during the acute exacerbation of the radicular pain.

Conclusion: CT-guided perineural root injection are a useful and risk free treatment for radiculopathy, and should be included to the armamentarium of conservative management of radiculopathy.

Titanium cranioplasties. Experience from a single institution

A. Tarnaris, H. Akhram, B. Arvin, J. Grieve, N. D. Kitchen & L. D. Watkins (Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK)

Objective: To review our experience of insertion of titanium cranioplasties in our institution.

Design: Retrospective review. Study period 13 years (1992 – 2005).

Subjects: Eighty-three cranioplasties in total.

Outcome measures: Demographics, indications and complications were recorded. The modified Rankin scale was used to record the neurological status.

Results: Fifty male and 33 female patients. Mean age at cranioplasty 41.06 years. Indications were: infection of previous cranioplasty, 45 (54.2%); trauma, 15 (18.1%); tumour, nine (10.8%); decompression due to increased intracranial pressure, seven (8.4%); and other reasons seven cases (8.4%). Forty-one (48.8%) had a single stage cranioplasty (titanium only) and 42 patients (51.2%) had delayed cranioplasty (another material used previously). In the latter category 38 had own bone flap cranioplasty and four had cranioplasty with acrylic plate. Mean time of cranioplasty after craniectomy 15.89 (median 7) months. Complication rate was 30.1% (25); 11 were acute (before discharge) and 14 were late (postdischarge). Acute complications were: infection (six); seizures (three); postoperative haematoma (one); and death (one). Late complications were: infection (four); chronic infection w/ sinus formation (one); epileptic seizures (three); headaches (two); chronic ventriculitis (one); cortical vein thrombosis (one); posttraumatic migraine (one); local pain (two). Mean time of postoperative complications from first cranioplasty was 16.07 (median 1.5) months. Eight out of the 11 infected plates were replaced. Mean time of reinsertion: 19.63 (median 7) months. Four plates were further infected and removed. Mean time of complications following reinsertion was 34.5 (median 32.5) months. 73.8% (n = 62) of the cases were followed up. Mean follow-up time: 27.6 months. 33 were improved compared with preoperative clinical status (mild in seven, moderate in three and marked improvement in 23 cases).

Conclusions: Our experience shows that titanium cranioplasty has emerged as a useful and acceptable alternative to other materials.

The role of endoscopic third ventriculostomy in the management of Chiari 1 malformation with hydrocephalus

C. Hayhurst, T. Pigott & C. L. Mallucci (The Walton Centre for Neurology and Neurosurgery, Liverpool, UK)

Objective: To evaluate the role of endoscopic third ventriculostomy in patients with Chiari 1 malformation and hydrocephalus with or without syringomyelia.

Patients and methods: A retrospective chart review of 14 adults and children identified from our endoscopy database (with age range 2 – 68 years). We reviewed the clinical features and radiographic findings of all patients. Twelve patients underwent ETV as primary management. Two patients had ETV at the time of shunt failure. All patients had obstructive hydrocephalus either at the aqueduct or 4th ventricular outflow obstruction. The length of follow-up is 5 months to 7 years.

Results: Only one patient (7%) required VP shunt following the ETV. Five (35.7%) patients progressed to foramen magnum decompression for persisting chiari or syrinx related symptoms. There were no operative or postoperative complications in any patient associated with ETV, and no CSF leaks or ICP-related problems following foramen magnum decompression.

Conclusion: ETV provides a durable method of treatment of hydrocephalus associated with Chiari 1 malformation. It is effective as the primary management and we advocate could replace routine VP shunt insertion for these patients. Management of the hydrocephalus alone is often sufficient, and may avoid subsequent need for decompression, although a significant proportion will still need both procedures.

Profiles of shunt—responders in normal pressure hydrocephalus

N. Keong, M. Wilby, B. Owler, M. Czosnyka, Z. Czosnyka & J. Pickard (Academic Neurosurgery Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, Cambridge, UK)

Objective: To analyse biometric profiles of patients who respond to CSF diversion and those who do not in the context of idiopathic normal pressure hydrocephalus.

Design: Prospective cohort of patients treated with CSF diversion with long term follow up. Statistical analysis using SPSS package.

Subjects: One hundred and twenty five patients (75 males, 50 females; mean age 71 years).

Outcome measures: Larsson NPH score, Stein-Langfitt score, computerized infusion study data.

Results: One hundred and twenty five patients underwent CSF diversion following CSF infusion studies. One patient died within 30 days of surgery. Seven patients developed significant complications following shunt insertion (four SDH, three shunt infections). Approximately 82% patients showed clinical improvement following shunting. Of the shunt responders, 15% showed late deterioration in spite of initial improvement. The different patient groups were further analysed in terms of biometric data.

Conclusions: Different phenotypes exist between shunt-responders and non-responders in normal pressure hydrocephalus. This may provide a basis for predicting the outcome in such patients.

Cerebrospinal fluid stunt infection in children: a 2 year experience of 348 cases

N. U. O. Jeelani, P. DeSilva, L. Zrinzo & R. Hayward (Department of Paediatric Neurosurgery, Great Ormond street hospital for Children, London, UK)

Object: Infection remains the most significant early complication of CSF shunts resulting in a high degree of mortality and morbidity. A number of centres have published their shunt infection rates, which range between 1 and 15%. Several predisposing factors have been suggested and analysed. In this study we have prospectively reviewed a cohort of children undergoing shunt insertions at our unit over a 2-year period.

Method: The GOSH database contains detailed information on all patients with CSF shunts managed in our unit. All data is collected contemporaneously with the event to which it pertains to. A 2-year period between 1 March 2000 and 28 February 2002, was chosen for analysis of shunt infections. A Cox proportional hazards model was used to analyse the impact of these variables on the incidence of shunt infections.

Results: A total of 348 shunt procedures were carried out in 353 patients over this 2-year period. One-hundred-and-thirty-one were new, 43 new post infection and 174 shunt revisions. The overall shunt infection rate was 9.7%. Of the variables studied, the impact of 4 is reported in here. Contrary to some of the current literature the age of the patient and the experience of the surgeon did not have a significant impact on the infection rate (see Table I). The infection rate was 12% for the emergency surgery and 7.5% for the routine surgery (see Table I), with a p value of less than 0.05. The strongest predictor of a shunt infection was a perioperative CSF leak. The presence of a leak, resulted in an infection rate of 73.3% as compared with 7.3% in the group with no leak.

Table I.

Conclusion: The experience of the surgeon and the age of the patient did not have a statistical impact on the infection rate. The presence of a perioperative CSF leak and the timing of the surgery were shown to be strong predictors for a shunt infection. Meticulous surgical technique is essential, to reduce the incidence of a perioperative CSF leak. Factors associated with ‘out of hours’ surgery need to be scrutinized stringently and wherever possible gold standards applied.

Cranioplasty infection rates following the adoption of shunt-like universal precautions

R. J. Mannion & P. J. Hutchinson (Academic Neurosurgery Unit, University of Cambridge & Addenbrooke's Hospital, Cambridge UK)

Objective: The potentially disastrous consequences of shunt infection are well known to all neurosurgeons, leading to the development of widely adopted peri-operative measures to reduce infection rates. Cranioplasty infection can be equally devastating, but the same peri-operative measures are not always followed. In 2003, we audited our infection rates for cranioplasty and were alarmed to find that it was 14%. We therefore adopted strict peri-operative measures and have re-audited our infection rates.

Design: Retrospective study of cranioplasty infection rate before and after the introduction of universal precautions.

Subjects: All cranioplasties inserted across specialities (neurosurgery and maxillofacial surgery) were retrospectively analysed from January 2003 until July 2005.

Outcome measures: Data collected included infection rate, microbiology results, type of plate used, grade of surgeon and the time of day, pre- and postintroduction of universal infection precautions.

Results: In 2003, 56 plates were inserted, of which eight were removed for infection (14% infection rate). Following the adoption of universal precautions, this infection rate fell to 5% (six out of 111 plates from Jan 2004 to July 2005). We will discuss in detail factors such as the measures introduced to reduce infection, antibiotic prophylaxis, whether infection rate differs depending on the type of plate (acrylic versus titanium) and the commonest pathogenic organisms.

Conclusions: Cranioplasty restores skull integrity, and provides both a positive cosmetic result and the potential to improve the rehabilitation process. Infection is a serious complication that can greatly set back the patient. With sensible precautions, adopted universally in our unit, the infection rate has been significantly reduced.

An enzyme – detergent method for effective prion decontamination of surgical steel

E. McKintosh, G. S. Jackson, E. Flechsig, K. Prodromidou, P. Hirsch, J. Linehan, S. Brandner, A. R. Clarke, C. Weissmann & J. Collinge (MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London, UK)

Objective: To develop an effective, practical and cost-effective method of sterilizing surgical steel contaminated with prions.

Design: Steel wires (5 mm) were incubated with brain homogenates from terminally sick prion-infected mice. These wires were then exposed to disinfection processes and inserted into the brains of indicator mice.

Subjects: Wild-type and Tg20 transgenic indicator mice.

Outcome measures: Mice were observed for the symptoms of prion infection, following published scoring systems. The brains of infected and non-infected mice were also examined by immunohistochemistry and/or Western blotting.

Results: Prions dried onto steel proved more infectious than wet homogenates. Porous load autoclaving was effective at 134°C for 18 min, but negated by any hindrance to steam access. None of the existing solutions marketed for prion disinfection proved effective. A novel detergent-enzyme was developed and did prove effective.

Conclusions: This novel detergent-enzyme mix has been designed to be easily added to pre-autoclave washes as an addition safeguard and is significantly more effective than solutions currently used for sterilizing non-autoclavable instruments. It is now under assessment by the National Institute for Clinical Excellence.

Tools for estimating the life-time risk of rupture of unruptured aneurysms (LTRRUA): an electronic and a look-up table

G. Narenthiran & J. P. Holland (Greater Manchester Neurosciences Centre, Hope Hospital, Salford, UK)

Objective: Based on these values from the updated ‘International study of unruptured intracranial aneurysms’ (ISUIA, 2003), clinicians often attempt to ascertain the life-time risk of rupture of unruptured aneurysms (LTRRUA) for their patients. However, this probability calculation is difficult to perform mentally. The aim of this project was to create tools to readily estimate the LTRRUA.

Design: From the 5-year cumulative rupture rates (according to the size and location of unruptured aneurysms from the updated ISUIA), we calculated the annual risk of rupture. We obtained the life-time expectancy values from the data published by the Government's Actuary Department, UK. Base on these values we calculated using ‘Microsoft Excel 2003’ the LTRRUA using the formula: LTRRUA = 100*{1−[(100−annual risk of rupture)/100]^life-expectancy}. We tabulated the results of the calculation: a ready-reference table to look-up the estimated LTRRUA for a particular patient. We also wrote a program using ‘Macromedia Flash 2004 Professional’ to calculate the LTRRUA when the user selects the gender, age, location and size of an unruptured aneurysm. The program used the data and formula that we had used in constructing the table. The program is compatible with computers running on Microsoft Windows, Apple MacIntosh and Linux operating systems.

Results: We were successful in creating a ready-reference table and an intuitive electronic calculator to estimate the LTRRUA.

Conclusions: The table and calculator are now regularly used at our neurovascular multi-disciplinary meeting to rapidly estimate the LTRRUA.

A risk-benefit analysis of stereotactic radiosurgery for cerebral arteriovenous malformations

R. R. Vindlacheruvu, P. Mitchell & A. D. Mendelow (Department of Neurosurgery, Newcastle General Hospital, Newcastle upon Tyne, UK)

Objective: To develop a mathematical model to analyse the stereotactic radiosurgery (STRS) in the treatment of cerebral arteriovenous malformations (AVM).

Design: An actuarial model was developed using age-specific annual mortality rates determined from the UK Census 2001. A Medline search supplemented by cross-referencing was used to determine rates of haemorrhage, death and disability for AVM with and without previous haemorrhage. The Pollock AVM score was used to predict outcome following STRS for a range of AVM—up to 3.5 cm diameter, in a range of locations 0—frontal or temporal, 1—occipital, parietal, cerebellar, corpus callosum, and 2—thalamic, basal ganglion, brainstem.

Outcome measures: Gain in independent life years as a consequence of treatment.

Results: Analysis of 4049 patient-years of data revealed a significant difference in annual haemorrhage rates for unruptured and ruptured AVM [2.68% (95% CI 2.1 – 3.4%), and 8.2% (95% CI 6.8 – 9.6%)]. Stereotactic radiosurgery is most beneficial for small ruptured AVM with deep venous drainage, for 3 cm AVM the gains are 12 and 6 years for locations 1 and 2, respectively, and for 2 cm AVM in the same locations the gains are 27 and 32 years, respectively. There is benefit for frontal or temporal previously ruptured AVM with superficial venous drainage. Marginal benefit for unruptured AVM is seen in particular situations only: locations 0 or 1, with deep venous drainage, diameter under 2 cm and age under 50 years old.

Conclusions: Mathematical modelling is feasible to assess the response of AVM to STRS. The greatest gains are for ruptured small AVM with deep venous drainage. For AVM in location 0, surgery may be a preferred option. The decision to randomize in the ARUBA study may be influenced by these results. There is a strong case for a national AVM registry.

Early cerebral blood flow changes in subarachnoid haemorrhage using computed tomographic perfusion software

S. Pushpananthan, V. Petrik & B. A. Bell (Academic Neurosurgery Unit, St George's, University of London, UK)

Objective: It is well recognized that cerebral blood flow (CBF) alterations occur after acute subarachnoid haemorrhage (SAH). Prevention of cerebral ischaemic damage relies upon an early diagnosis of falling CBF. CT perfusion (CTP) is a relatively new tool, which may provide useful information in patients with SAH.

Design: An analysis of 1517 regions of interest on CTP within the anterior, middle and posterior cerebral artery territories of 64 patients. CTP images were obtained and analysed using standard CT scanner software. ANOVA was used for data analysis.

Subjects: Thirty male and 34 females referred to our unit with confirmed SAH aged 22 – 79 years (mean: 43). The timing of CTP post ictus ranged from 8 to 48 h (mean 26).

Outcome measures: Quantitative values for cerebral blood flow, cerebral blood volume and mean transit time were correlated with World Federation of Neurological Surgeons (WFNS) clinical grade and Fisher CT grade.

Results: Mean CBF decreased with increasing Fisher grade.

Table

There was little difference in CBF between patients with WFNS grades I, II or III, however, there was a significant difference between mean CBF in WFNS Grade I (51.42 ml/100 g/min) and Grade V (45.80 ml/100 g/min; p < 0.01 t-test).

Conclusions: We have shown, using a new imaging technique, that early ischaemia occurs within the first 24 h post ictus and that the severity of this is related to the amount of blood seen on the initial CT scan.

Effects of acute Pravastatin therapy on sepsis control, hospital stay, and long-term outcome in patients after aneurysmal subarachnoid haemorrhage

M.-Y. Tseng, P. J. Hutchinson, J. D. Pickard & P. J. Kirkpatrick (Addenbrooke's Hospital, University of Cambridge, Cambridge, UK)

Objective: We have demonstrated that acute pravastatin therapy following aneurysmal subarachnoid haemorrhage (aSAH) can reduce vasospasm and delayed ischaemic deficits.[1] We assessed the hypothesis that these effects were associated with better sepsis control, shortening of hospital stay and improvement in long-term outcome.

Design: A phase II randomized controlled trial.

Subjects: Eighty aSAH patients (age 18 – 84 years) within 72 h from ictus were randomized equally to receive either oral pravastatin (40 mg/day) or placebo for up to 14 days.

Outcome measures: Durations of noradrenaline use for controlling sepsis-related hypotension, hospital and NCCU stays, and 6-month Glasgow Outcome Scale are compared between the two groups.

Results: The duration of noradrenaline use for sepsis showed a tendency towards being shorter in the pravastatin group (placebo v. pravastatin, 7.0 ± 5.3 v. 3.7 ± 3.2 days, t-test p = 0.07) indicating a more rapid resolution of profound sepsis. The eight deaths in the placebo group included five vasospasm-related cerebral infarcts. Neither of the two deaths in the pravastatin group was related to vasospasm (log-rank test p = 0.02). Among the 70 survived patients, linear regression revealed that in addition to the four factors prolonging the stays (sepsis, ventriculitis, immediate postoperative deficits, and WFNS grade), pravastatin shortened the total hospital (coefficient −0.1 day, p = 0.06) and NCCU stays (coefficient −0.7 day, p < 0.001). Logistic regression showed that the reduction in disability by acute pravastatin therapy seemed to persist after 6 months (odds ratio 0.3, p = 0.078).

Conclusions: These data support beneficial effects of acute pravastatin therapy following aSAH. A large multi-centred trial is proposed.

Brain stem cavernomas: a neurosurgical view point

A. Tarnaris, N. D. Kitchen, R. P. Fernandes & I. Chopra (Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK)

Objective: To assess the management for brain stem cavernomas in a surgical and conservative group.

Design: Retrospective review of medical records (1995 to 2004). Statistical analysis of results (univariate analysis).

Subjects: Twenty-one cases, six surgical and 15 non-surgical.

Outcome measures: Change in pre- and postoperative modified Rankin scale score and Barthel Index at last follow-up.

Results: Seven male and 14 female. Mean age on presentation: 36.8 years. Two familial and eight patients with multiple cavernomas. Presentation: haemorrhage twelve; neurological deficit five; and incidental finding four. Cavernoma location: pons 13; midbrain four; medulla oblongata two; cervicomedullary junction one; and multiple cavernomas one patient. Follow-up in 20 patients. Mean follow up period: 79.7 months (median 70 months). Ten patients rebled during this period. Retrospective bleeding rate (from birth) was 1.55% and prospective bleeding rate was 7.17% per patient year for all patients. No mortality in either group. Three cases were reoperated. Fourteen patients had a further neurological event during follow-up. There were statistical differences between the types of management/presentation and the risk of rebleeding (p = 0.04). The outcome was worse in the case of multiple cavernomas (p = 0.012). The conservative group had a better functional outcome when assessed with the Barthel Index compared with the surgical group (average BI 93.9 v. 84, respectively).

Conclusions: Conservative management offered better functional outcome when compared with surgery on a long-term follow-up; this difference was not statistically significant in order to support a change in practice. It is recognized that surgery is indicated in some cases, but the risks and limitations need to be understood.

Shaken Baby Syndrome before the Court of Appeal

P. Richards (Radcliffe Infirmary, Oxford, UK)

Since the early 1970s the triad of acute encephalopathy, subdural haemorrhage and retinal haemorrhage has been accepted by the majority of paediatricians as indicative of infant non-accidental injury, usually by shaking with or without impact. The condition has become known as the ‘Shaken baby Syndrome’.

Since the beginning of this century the concept of the ‘Shaken Baby Syndrome’ has been under attack, mostly from practitioners outside the field of paediatrics and paediatric head injury management. Some have argued that fatal or disabling injuries can occur from minor injuries, whilst others have put forward theories that the features of the triad are the result of mis-diagnosed medical conditions and nothing to do with trauma. Vaccination in the presence of sub-clinical vitamin C deficiency was one such theory which most ignore.

Another theory that has gained a lot of publicity recently was that acute hypoxia from whatever cause could lead to sub-dural and retinal haemorrhaging. This theory was known as the ‘Geddes’ or ‘Unifying’ hypothesis.

Whilst rejected by most clinicians these challenges were increasingly used in the courts, both criminal and civil. Following the cases related to ‘Munchausen by Proxy Syndrome’ and questionable expert medical evidence the Attorney General ordered a review of all cases of ‘Shaken Baby Syndrome’ convicted on medical evidence alone. 4 test cases were identified and they were re-examined by the Court of Appeal in June 2005 with judgement published at the end of July.

The author gave evidence on the neurosurgical aspects of the condition at the request of the Crown Prosecution Service in all four cases. He presents the background to the appeals, the outcome, and the implications for future investigation and management of suspected non-accidental infant head trauma.

Could the ‘Virginia Prediction Tree’ accurately predict outcome in the severely head-injured patients?

K. Woon, J. Fitzgerald, Y. Yap, D. Macarthur, A. Jacobs, D. Sperry & P. Yeoman (Department of Neurosurgery and Department of Intensive Care, Queens Medical Centre, Nottingham, UK)

Objective: The Virginia Prediction Tree (VPT) was developed from an analysis of outcome of 555 patients admitted to the Medical College of Virginia (MCV) between 1976 and 1989. Threshold levels of prognostic factors were used to split the patients into subgroups with varying degrees of risk[1] and presented in a visually useful way. The overall predictive accuracy in the original data was 77.7%. We applied this tree diagram to our unit's dataset of severe head injuries to examine its reproducibility.

Design: Analysis of prospectively collected data from the unit's dataset collected between 1995 and 2003, using the methodology described by Choi et al.[1] Patient management was similar to the MCV series.

Subjects: Six-hundred-and-fifteen patients met the entry criteria (GCS <9, Motor Score <6) of which outcome data was available in 596 patients (97%).

Outcome measures: Glasgow Outcome Score at 1 year recorded by the patient's general practitioners using a standard questionnaire.

Results: In our unit, the overall predictive accuracy is 75% with accuracy of prediction in subgroups ranging from 51 to 85%.

Conclusions: The Virginia Prediction Tree remains around 75% accurate in predicting outcome into broad prognostic groups. Within individual prognostic subgroups however its predictive accuracy was lower, sometimes no better than 50/50. Case mix and extent and severity of extracranial injury may limit its application.

Relationship between cerebral temperature and metabolism in patients with traumatic brain injury

I. Timofeev, J. Nortje, P. G. Al-Rawi, A. K. Gupta & P. J. Hutchinson (Academic Neurosurgical Unit, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK)

Objective: To investigate the relationship between cerebral temperature and metabolism following traumatic brain injury in patients treated with graded induced hypothermia.

Design: Analysis of prospectively collected data (physiological parameters; brain tissue and microdialysis monitoring). Macroscopically intact tissue in relation to catheter location was classified on CT as ‘normal brain’ and pericontusional areas as ‘tissue at risk’. The dataset was divided in three groups based on brain tissue temperature values (36 – 37°C—normothermia, 34.5 – 35.9—moderate and <34.5—advanced hypothermia).

Subjects: Twenty-six patients admitted to a neuro-intensive care unit following traumatic brain injury (3700 h of monitoring).

Outcome measures: Comparison of brain tissue monitoring and microdialysis parameters [lactate/pyruvate (L/P) ratio as a marker of anaerobic metabolism, glycerol as a marker of cell membrane breakdown] between advanced and moderate hypotherma and normothermia groups.

Results: Moderate hypothermia was associated with lower L/P ratio values in tissue at risk compared with normothermia (26 ± 0.4 v. 37 ± 0.73, p < 0.001). In the advanced hypothermia group glycerol levels were significantly higher in both ‘normal’ (76 ± 2.8 μM) and ‘at risk’ brain tissue (142 ± 2.4 μM) compared with the normothermia group (57.9 ± 2.7 μM and 87.2 ± 3.2, respectively, p < 0.005). In addition, the L/P ratios were also significantly higher (p < 0.005). Brain tissue oxygen tension was overall lower in advanced hypothermia group, in keeping with our previous findings. There was no significant difference in CPP and ICP levels between moderate and advanced hypothermia groups.

Conclusions: Moderate hypothermia is associated with a significantly lower L/P ratio in tissue ‘at risk’. Advanced hypothermia may be deleterious, being associated with reduced tissue oxygen tension, increased anaerobic metabolism and increased cellular breakdown. These effects are most prominent in vulnerable tissue.

Multi-centre study of decompressive craniectomy in traumatic brain injury: www.RESCUEicp.com

P. J. Hutchinson & P. J. Kirkpatrick, on behalf of the investigators (Academic Neurosurgery Unit, Addenbrooke's Hospital, University of Cambridge, UK)

Objective: To provide Class I randomized evidence as to whether decompressive craniectomy is effective for the management of patients with raised and refractory intracranial pressure following traumatic brain injury.

Design: A multicentre randomized trial comparing decompressive craniectomy with medical management. There are two randomized arms: continuation of optimal medical management (including barbiturates) versus surgery (decompressive craniectomy).

Subjects: Patients with traumatic brain injury requiring ventilation and ICP monitoring (n = 50 for pilot phase, n = 400 for main study). Inclusion criteria: traumatic brain injury, age 10 – 65 years, abnormal CT scan requiring intra-cranial pressure monitoring with raised ICP (>25 mmHg) refractory to initial treatment measures. Exclusion criteria: bilateral fixed and dilated pupils, bleeding diathesis, devastating injury not expected to survive 24 h.

Outcome measures: Extended Glasgow Outcome Score at 6 months, SF-36 quality of life questionnaire at 6 months, ICP control, length of stay in ITU, length of stay in Neurosurgical Unit.

Results: The pilot phase of the study is on-going. The data monitoring committee held its first meeting after the first 10 patients were recruited and indicated that the study should proceed. The background, protocol, progress of the study will be presented.

Conclusion: Randomizing patients with traumatic brain injury to decompressive craniectomy versus optimal medical management is feasible. Whether this operation is effective and safe remains to be seen.

The role of the neurosurgeon in antenatal counselling

S. Bassi, J. Jarosz & M. Murphy (Kings College Hospital, London, UK)

Introduction: Advances in imaging and technology have progressed at an exponential rate. Historically antenatal screening has been performed via a combination of markers and ultrasound, along with the limited use of amniocentesis and chorionic villous biopsy. Over the last few years foetal MRI scanning has gained favour in patients who may have a potential abnormality diagnosed on ultrasound. The resolution and detail seen on the MRI has led to more subtle cranial and spinal abnormalities being detected. This has a knock-on effect of a larger number of expectant mothers being referred to the paediatric neurosurgical service for guidance, advice on termination and prediction of neurological outcome for their ‘child’.

Aims: To assess the case mix of patients referred to the paediatric neurosurgical service over a 1-year period with an attempt to collate foetal MRI findings with the outcome of the pregnancy/termination, and to assess the development issues in any of the children born with foetal MRI scan abnormalities.

Methods and materials: All consecutive referrals from foeto – maternal medicine over a 1-year period were assessed. The timing and findings of the scans and the diagnosis were reviewed. The outcome of the pregnancy was documented. The advice given by the neurosurgeon was noted. Any children born were assessed with reference to their development progress set against their foetal MRI findings.

Results: We present a spectrum of abnormalities seen on the foetal MRI scanning. The neurosurgical advice given is highlighted. The outcome for each parent counselled is discussed. The neurological abnormalities in the children are documented.

Discussion: We discuss the moral and ethical issues with screening for neurological abnormalities. We also discuss the advice given to the parents and the lack of evidence with which one can make judgements on scan findings in relation to neurological outcome. We question whether the neurosurgeon is ideally placed to counsel potential parents, when that advice may help parents to decide on termination or continuation of that particular pregnancy.

Paediatric vascular intracranial complications of sickle cell anaemia

I. Liaquat, M. Murphy & P. R. Bullock (Kings College Hospital, London, UK)

Objective: To enumerate possible intracranial vascular sequelae of Sickle Cell Disease, to identify risk factors and outline management strategies.

Design: Retrospective review of a single unit experience managing vascular intracranial complications of sickle cell disease from 2000 until 2005. Information such as homozygosity/heterozygosity, duration of disease, disease control as indicated by haematology follow up, concurrent SCD-related health problems and neurosurgical management was recorded. The pattern of vascular disease was analysed to reveal possible contributory/risk factors towards development of vascular intracranial complications.

Subjects: All patients presenting with vascular intracranial complications of sickle cell disease from 2000 to 2005 were evaluated.

Outcome measures: Classification of vascular intracranial complications into one or more of the following categories: aneurysmal subarachnoid haemorrhage; non-aneurysmal subarachnoid/ intraventricular haemorrhage; vasculitis.

Results: There were 10 patients in the study. All symptomatic vascular intracranial complications of sickle cell disease were homozygous for SCD. Aneurysms were likely to be multiple. Ruptured aneursyms in SCD were of a smaller size average 2 mm. There was a propensity for aneurysms to occur in the posterior circulation, in particular the posterior cerebral artery was frequently involved. Patients with aneurysms and Moyamoya-type vasculitis were likely to have occlusive disease of the internal carotid arteries

Conclusions: The vascular intracranial complications of sickle cell disease have an aggressive natural history. Tight control of SCD may reduce the possibility of complications. Complications that arise should be managed in the context of the disease entity rather than in isolation. Consideration should be given to by-pass procedures, parent vessel ligations and revascularization techniques. Transcranial Doppler may be used to identify SCD patients at risk of aneurysmal rupture.

Two-dimensional chemical shift imaging in the surveillance of low grade gliomas

M. Murphy, D. J. O. McIntyre, J. R. Griffiths, H. T. Marsh & B. A. Bell (Academic Neurosurgery Unit and Basic Medical Sciences, St. Georges University of London, UK)

Objective: To investigate a role for two-dimensional chemical shift imaging (2D-CSI), in the surveillance of low grade gliomas.

Design: 2D-CSI is a multivoxel magnetic resonance spectroscopy (MRS) technique, which allows biochemical evaluation of 16 adjacent tissue voxels in a grid for quantification of metabolites in a region of interest (ROI).

Subjects: 2D-CSI was performed on 6 normal subjects, 11 patients with tumours prior to resection and 16 patients who underwent postoperative surveillance scanning.

Outcome measures: Each subject was placed in a radiological category based on the findings on FLAIR and T1-weighted contrast sequences (T1WC). They were categorized as having high (+) or low (−) signal on FLAIR and as having some (+) or no (−) enhancement on T1WC sequences. The main outcome measure used for each patient was maximum choline:creatine value in the 16 voxels of the 2D-CSI grid.

Results: The average maximum choline:creatine value for the 6 normals was 1.32. For those who were FLAIR + and T1WC- it was 1.67. The average ratio was 3.43 for those who were FLAIR + and T1WC +.

Conclusions: Higher maximum choline:creatine levels were associated with the presence of tumour compared with patients who were disease-free and were also associated with lesions of higher histological grade. A maximum choline:creatine ratio of <1.5 was associated with the absence of tumour and a ratio of >1.8 with the presence of tumour. 2D-CSI can play a very useful role in the surveillance of low grade gliomas and provide early warning of recurrence and malignant transformation of the tumour.

‘31/ 62’ are we there?

S. Achawal, S. Levy, A. Koukkoulli, J. Ainsworth & R. Bradford (Department of Neurosurgery Royal Free Hospital London, UK)

Introduction: National Cancer Wait Project has recommended 31 – 62 days limit for the diagnosis and treatment of cancers.

Objective: The study aims to analyse a patient's journey through a Neurosurgical unit to definitive oncological treatment to determine whether we fulfil the recommendations.

Study design: The study was carried out on 62 patients who were newly diagnosed with primary malignant brain tumours from November 2004 to October 2005 in our department. Waiting times were measured for various stages of the journey from the date of first referral to neurosurgeon till start of definitive neuro-oncological treatment. This data was collected from referral forms, inpatient notes, electronic discharge summaries, operation theatre log, PAS system, MDT meeting proceedings and neuro oncology notes.

Outcome measures: Various time intervals between first referral, admission, biopsy, MDT meeting, first neuro-oncological consultation and start of definitive treatment were measured.

Results: Ages ranged from 19 years to 84 years with 44 male and 18 females. Histopathology results were: 34 GBM, 23 Astrocytomas, five others. The average wait for admission from referral was 5.3 days, for biopsy was 4.1 days, for MDT meeting was 7.8 days, for oncology consultation was 10.3 days and for oncological treatment was 21.1 days. The average total wait till definitive treatment was 48.6 days.

Conclusions: The case of diagnosis of malignant brain tumours differs from the wait for diagnosis at other sites. The clock should start on the date of first scan that suggests a tumour. Measures need to be taken to reduce the wait at each stage.

Electromagnetic neuronavigation: early experience and applications

C. Hayhurst, P. Byrne, D. F. O'Brien, P. R. Eldridge & C. L. Mallucci (Walton Centre for Neurology and Neurosurgery, Liverpool, UK)

Objective: A review of early experience with an electromagnetic neuronavigation system, to highlight the varied applications and advantages in the paediatric population.

Patients and methods: To date we have performed 36 cases using electromagnetic neuronavigation in patients with an age range of 3 months to 77 years. Both rigid and scalp applied reference fiducials were employed. This series includes 16 CSF diversion procedures for complex hydrocephalus (slit ventricles, multicompartmental hydrocephalus), four ommaya placements for CNS leukaemia and cystic tumours and 15 ventriculoperitoneal shunts in routine cases. This series includes endoscope assisted image guided ventricular catheter placement.

Outcome: All CSF diversion cases achieved satisfactory placement of the proximal catheter, confirmed on postoperative imaging. There were no intra or postoperative complications. No patient has to date required a revision of their CSF diversion device. We have encountered no problems with interference with other instruments in the surgical field.

Conclusion: Electromagnetic technology avoids the problems of line of sight and the need for rigid head fixation seen with most other digital spatial localizing systems. This facilitates the application of image-guided surgery to a wider series of patients. The introduction of non-invasive localizers facilitates use in all shunt surgery, avoiding sub-optimal ventricular catheter placement and subsequent shunt malfunction. The system is straightforward and rapid to use, an important consideration when CSF diversion needs to be performed out of hours.

Virtual neuro-endoscopy and rehearsal of surgery using a Haptic based device

M. Foroughi, N. Rodwell, S. Corner, R. Nannapeneni & R. H. Hatfield (University Hospital of Wales, Cardiff, UK)

Objective: To develop a low-cost computer based virtual neuro-endoscopic system with a haptic device simulating an endoscope.

Design: The system has been designed around a standard PC workstation with a dedicated volume rendering card. The TeraRecon VolumePro card uses ray-casting to visualize large volumetric data sets in real-time. The system loads sequential or multi-image DICOM files from CT or MRI scans into a 3D volume. Slices are spatially resequenced automatically using DICOM file information. Tissue types can be selected using segmentation procedures based on an easy to use interface. Complex selection and colourization for the data can be achieved, dependent on the original greyscale values. Useful colourization data sets may be saved, swapped and loaded. A movable light source allows surface contours to be analysed. A virtual endoscope can be placed into the segmented data to allow complete virtual endoscopic simulation. A camera view is created for the virtual endoscope with a configurable field of view and lens tilt, enabling simulation of real world camera lenses. Data can be clipped to a sub volume, using click and drag interface. Selection of point of interest allows the camera to focus on a region, and navigation of data using mouse control or simulated endoscopic input device. The simulated endoscopic input utilizes a low cost haptic system based on the SensAble Omni device. The total cost of the device is £4000. Virtual volumetric and real world haptic coordinate systems are spatially mapped, giving real world motion for the virtual camera. The haptic device can use a force feedback mechanism to simulate a pre-set tissue resistance. The system can be switched to a stereoscopic mode allowing greater depth perception of DICOM data sets. Stereoscopic active stereo glasses and passive filter systems are both fully supported and automatically detected.

Subjects: A total of 20 CT and MRI data sets were analysed using our virtual neuro-endoscope.

Outcome measures: A subjective analysis by one neurosurgeon regarding user friendliness and perception of individual patient anatomy for neuro-endoscopic and open procedures.

Results: All CT and MRI scans were loaded and ready for interaction within five minutes. The system was user friendly and greatly enhanced perception of individual patient anatomy, and allowed rehearsal of neuro-endoscopic procedures.

Conclusions: This innovative combination of haptics and stereo/mono 3-dimensional imaging enhances the realism of virtual neuro-endoscopy The system is a user friendly tool, which enhances appreciation of individual patient anatomy and allows rehearsal of neuro-endoscopic procedures. This system can be applied to other body regions e.g. the gastrointestinal and urinary tract.

Co-registration of the SonoSite Ultrasound probe with Neuro-navigation; an alternative to intra-operative MRI

A. Chakraborty, C. Uff, R. Bradford & N. Dorward (Royal Free Hospital, London, UK)

Objective: The SonoSite® Ultrasound system is available in most operating departments to assist central line insertion. The SureTrack universal adaptor® in conjunction with the StealthStation Neuro-navigation system® allows navigation with different instruments. We have used the SonoSite Ultrasound Probe® co-registered with the StealthStation System® using the SureTrack universal adaptor® during brain tumour resection.

Design: Prospective study using 10 patients. The SonoSite iLook 25 ultrasound system® using the L25/10 – 5 MHz probe was used.

Outcome measures: Trajectory views on the StealthStation® provided images in the same plane as the ultrasound image in all cases. Skin and brain surface accuracy of co-registered ultrasound were assessed by placing the probe on the appropriate surface and, on the StealthStation screen, measuring distance from the probe's surface to the appropriate surface.

Results: Brain tumour contrast was not as obvious using ultrasound compared with the trajectory view MRI. Surface accuracy was an average 1mm. Accuracy following dural opening ranged from −2 mm to +5 mm with a mean shift of +2.5 mm. Thus, in the majority of cases, when dura was opened, brain and/or tumour bulged out of the cranial cavity.

Conclusions: This system is an inexpensive and simple method for determining accuracy of tracking of neuronavigation. Use of historically acquired MRI data in conjunction with real time ultrasound data provides the surgeon with more confidence when navigating once dura has been opened. The equipment required is likely to be accessible to most neurosurgical units in the UK and may provide an inexpensive alternative to intraoperative MRI.

Quality of life following meningioma surgery measured using the General Health Status Questionnaire SF36v2

V. Apostolopoulos, K. Verma & J. Pollock (Oldchurch Hospital, Romford, UK)

SF36v2 is a well-documented and validated general health questionnaire that has been employed for a wide range of conditions. The questionnaire provides a measure of health within eight ‘domains’, or parameters. These including physical function, mental health and levels of bodily pain.

Objective: To measure quality of life using SF36v2 in a group of patients operated for intracranial meningioma and to compare these results with data from the normal UK population.

Patients and methods: A telephone and postal survey was carried out in 49 patients. 91% of the meningiomas were supratentorial and the remainder infratentorial. Fifty-eight per cent of tumours were of WHO grade 42% and I WHO II. The outcome data were analysed using the SF36v2 scoring software. Comparative data for the normal UK population were obtained from the Oxford Healthy Lifestyle Survey (1997).

Results: All 49 patients responded. One form was excluded as it was not adequately completed. Analysis of the remaining 48 patients showed that the quality of life of patients operated for intracranial meningiomas compared favourably with the mean UK population. The differential between the two groups was greatest for the physical domains rather than for mental or emotional domains. WHO Grade I patients had higher scores indicating a better quality of life in all domains than WHO Grade II patients.

Conclusion: SF26v2 is a suitable and practical instrument for measuring and comparing quality of life in this patient group.

Prospective study to evaluate the effect of wearing a hard collar after anterior cervical discectomy (ACD) without fusion

H. Georges, W. A. Liebenberg, D. Horney, C. Good & G. R. Critchley (Hurstwood Park Neurological Centre, Haywards Heath, UK)

Objective: ACD without fusion is an accepted treatment for cervical intervertebral disc prolapse. Ongoing concerns exist about postoperative changes in the angle of kyphosis (AOK). Our aim was to establish whether wearing a hard collar for 6 weeks postoperatively would affect the changes in AOK and have any impact on outcome.

Design: Prospective randomized trial, patients randomly allocated in two groups. Group 1—ACD, wearing hard collar for 6 weeks postoperatively. Group 2—ACD, not wearing collar.

Subjects: Eighteen patients, nine in each group.

Outcome measures: Change in AOK assessed by comparing pre and postoperative lateral C-spine X-rays. Clinical outcome assessed on Pre- and postoperative completed SF36 and Northwick park neck pain (NPQ) questionnaires.

Results: Mean AOK preoperatively 7.33° (group 1) and 7.22° (group 2). Mean of 227.72 days between ACD and postoperative X-rays and questionnaires. Mean change in AOK postoperatively 7.39° (group 1) and 2.00° (group 2), which is statistically significant (p < 0.05). There is significant postoperative improvement in five dimensions of the SF 36 (RP, SF, EV, P, CH) and the NPQ in group 2, while just one dimension of the SF 36 (SF) has improved in group 1.

Conclusions: Patients that undergo ACD without fusion and do not wear hard collars post operatively have less change in the AOK and have significant improvement in their quality of life.

Incidence of epilepsy as a presenting complaint in intracranial meningioma surgery

S. Ayala, J. Lafuente, L. Watkins, D. T. Thomas & J. Martinez-Canca (National Hospital for Neurology and Neurosurgery, London, UK)

Objective: To evaluate the incidence of epilepsy as a presenting complaint in intracranial meningiomas.

Patients and methods: More than 1000 patients were recruited retrospectively. Patients were collected from the National Hospital for Neurology and Neurosurgery in London from 1963 to 2000 using pathology reports and clinical notes. Patients included were those that had undergone surgery for intracranial meningiomas. We collected: demographic data, location of meningioma, age, sex and presenting clinical symptoms. We also evaluated the number of patients who became epilepsy free after 6 months of the surgery. Data was analysed using stats view® using univariate and multivariate analyses. The study had Ethics committee approval.

Results: More than 1000 patients: 65.24/34.76 female/male ratio. Age ranged from 13 to 96 years. 18.26% of meningiomas were located in the convexity; 18.5% were located in parasagittal area and falx; 5.94% in the posterior fossa; 9.13% suprasellar; 1.21% intraventricular; 1.98% were cavernous sinus meningiomas; 0.66% were pineal meningiomas; 4.07% appeared in the cerebello-pontine angle; 4.51% in the optic nerve and orbital region; 11.88% in the sphenoid ridge; 14.85% were subfrontal meningiomas; 1.32% clival meningiomas; 2.97% were located in the petrous/apex; finally, 5.07% were unclassified. 18.92% of the patients had suffered an epileptic fit as first presenting complaint. We present the incidence of epilepsy in each tumour location. As well as the different types of epilepsy described which included tonic-clonic seizure, focal seizures, absence seizures, jacksonian episodes and sensorial epileptic events. Almost 100% of epileptic presentations had EEG studies registered.

Conclusion: Epilepsy is a known presenting symptom in patients that suffer from intracranial meningiomas. Our series (one of the largest meningioma studies in the literature) analyses the incidence and multiple features of epilepsy in patients suffering from this benign pathology.

Change in management strategies of acoustic neuroma. Review of 405 cases over the last 15 years

R. Bradford, H. El-Maghraby, R. Khong, C. Collis, R. Quiney & A. Wright (Department of Neurosurgery, Department of Radiotherapy and Oncology, Department of Ear, Nose and Throat Surgery, Royal Free Hospital, Royal National Throat, Nose and Ear Hospital, UK)

Objective: Management of acoustic neuroma presents a therapeutic dilemma.[1] The aim of this study is to review the change in management strategies.

Design: Retrospective chart review.

Subjects: Three groups. Group I, II, III, were for 1990 – 1994, 1995 – 1999 and 2000 – 2004, respectively.

Outcome measures: Achieve maximum tumour control with maximum neurological function preservation and patient satisfaction.

Results: Ninety-one cases managed in group I: Suboccipital in 49 cases (53.8%), Translabyrinthine in 23 cases (25.3%), Middle fossa in 10 cases (11%), Stereotactic radiotherapy in one case (1,1%) and surveillance in eight cases (8.8%). One hundred and ninety cases managed in group II: suboccipital in 97 cases (57%), translabyrinthine in 46 cases (27%), stereotactic radiotherapy in 13 cases (7.7%) and surveillance in 14 cases (8.3%). One hundred and forty four cases managed in group III: suboccipital in 78 cases (54%), Translabyrinthine in eight cases (5.5%), Stereotactic radiotherapy in 31 cases (21.5%) and surveillance in 27 cases (19%). Fifty-two cases required subsequent management as such: suboccipital in 13 cases (13%), translabyrinthine in seven cases (13.5%) and stereotactic radiotherapy in 32 cases (61.5%). Maximum tumour control, maximum neurological function preservation and patient satisfaction have improved from one group to another. Many variants have been studied, but the introduction of stereotactic radiotherapy, and wait and see with the reduction of middle fossa and translabyrinthine were statistically significant.

Conclusion: Suboccipital approach remains the cornerstone of management. stereotactic radiotherapy and surveillance have an increasing role. Acoustic neuroma management requires a multidisciplinary teamwork to achieve the patient's best interest.

Intraventricular tumours in adults

A. K. Demetriades, T. Elias, P. Kalsi, P. D. Minhas & H. Marsh (Department of Neurosurgery, Atkinson Morley Wing, St George's Hospital NHS Trust, London, UK)

Introduction: Intraventricular tumours (IVTs) constitute a rare and heterogeneous group of brain tumours, accounting for less than 1% of all primary intracranial lesions. A wide range of tumours arise from the ventricles and an accurate diagnosis is rarely possible from the clinical and radiological appearances, and a pathological diagnosis is essential for optimal management.

Objective: To assess the incidence, radiological characteristics, surgical management and histological type of IVTs.

Design: Three-year retrospective study of patients with an IVT at a tertiary neurosurgical centre in London (Jan 2003 to Nov 2005).

Subjects: Patients undergoing excision of an IVT were identified from theatre logbooks. Histopathological diagnosis was obtained for all cases. Clinical presentation, management and outcome obtained from case notes.

Results: Forty-three patients identified with an IVT. All were primary tumours. One tumour was recurrent. 22 IVTS were benign: colloid cysts (17), meningiomas (two), arachnoid cysts (two) and multiple haemangiomata (one). The remainder were primary neoplasms: 15 were low grade (I and II) and six high grade (III and IV); seven craniopharyngiomas (grade I), two chordoid gliomas (grade II), three astrocytomas (2 grade I and 1 grade II), one haemangiopericytoma (grade II), three central neurocytomas (2 grade II, 1 grade III), one choroid plexus carcinoma (recurrent, grade IV), two glioblastomas (grade IV) and two PNETs. Twenty IVTs were excised using the transcallosal approach; nine transcortical; 12 endoscopic biopsy/aspiration. Two were excised using other approaches. There was only one death in a patient who was not operated on. Duration of follow-up was from 1 to 33 months. High-grade tumours received adjuvant radio- and/or chemotherapy.

Conclusions: The majority of IVTs in this series were benign or low grade. Clinical, radiological and histological features combined can reliably provide the correct diagnosis. While the majority of excisions were by the transcallosal approach, endoscopic techniques were commonly used for biopsy/aspiration. High grade tumours are amenable to adjuvant radio- and/or chemotherapy, but numbers are small for prognostic statistics.

DTI and tractography can predict tumour histology

T. J. D. Byrnes, T. R. Barrick, C. Ladroue, C. A. Clark & B. A. Bell (Academic Neurosurgery Unit, St George's University of London, UK)

Objective: To investigate the ability of diffusion tensor imaging (DTI) and tractography to discriminate between different brain tumour types in vivo.

Design: All patients studied underwent DTI and subsequent tractography prior to definitive treatment for their intracranial tumour. DTI and tractography metrics were calculated for the tumour as a whole and for the peritumoural oedema. These variables were then combined and a statistical model created to enable clustering of the various tumour types. In order to test the model and its ability to predict tumour type, the process was carried out iteratively leaving out one subject at a time, and then the histology of the excluded subject's tumour was predicted by comparison with the model.

Subjects: Thirty-six patients: 12 females and 24 males with an average age of 60 (range 27-73), 16 glioblastoma, 12 metastasis, eight meningioma.

Outcome measures: Histological diagnosis. Statistics: principal component analysis and linear discriminant analysis.

Results: The technique correctly predicted glioblastoma in 69%, meningioma in 75% and metastasis in 100% of cases.

Conclusions: DTI and tractography metrics are useful in the diagnosis of patients with brain tumour and could potentially reduce the requirement for surgical biopsy.

Uncoupling protein-2 polymorphism and risk of adverse outcome after subarachnoid haemorrhage

L. Morgan, J. Cooper, H. Montgomery, S. Humphries & N. Kitchen (National Hospital for Neurology and Neurosurgery, London, UK)

Objective: Uncoupling protein-2 (UCP-2) is suspected to be part of a mechanism protecting the brain against oxidative stress. A polymorphic variant (−866G > A) exists of the UCP-2 gene in which the common allele produces less UCP2. We tested the hypothesis that patients with subarachnoid haemorrhage and the common UCP-2 allele were more likely to present with a high Hunt and Hess grade, high Fisher grade on CT, have vasospasm or an adverse outcome, compared with patients with the rare allele.

Design: Genotypes were determined by DNA extraction, polymerase chain reaction amplification and endonuclease digestion.

Subjects: Seventy-four Caucasian patients presenting to our unit with aneurysmal subarachnoid haemorrhage and 2695 healthy controls.

Outcome measures: Allele frequencies were determined via gene counting and differences between the genotype distributions and allele frequencies were considered via chi-squared tests or fisher's exact tests as appropriate.

Results: Patients with SAH had an increased odds ratio of 40% of being AA compared with controls. The AG/AA genotype was significantly associated with vasospasm and with outcome after GCS.

Conclusions: This is the first study to look at this candidate polymorphism in this group of patients. This study has suggested that uncoupling protein −2 is a modifier of outcome in subarachnoid haemorrhage and is involved in vasospasm. It may be directly involved in protecting the brain against oxidative stress.

The role of image guided framed based stereotaxy in the management of brainstem lesions

L. Yap, A. Brodbelt & P. C. Warnke (The Walton Centre for Neurology and Neurosurgery, Liverpool, UK)

Objective: The role of stereotactic biopsy in the management of supratentorial brain tumours is well established. However, controversy persists as to the use of stereotactic biopsy in brainstem lesions. The aim of this paper was to evaluate the safety and accuracy of this procedure in the management and treatment of brainstem lesions in both adults and children.

Design: Retrospective analysis of patient records, histology, and imaging.

Subjects: Thirty-eight stereotactic procedures were performed on 31 consecutive patients (24 adults and seven children) between August 2000 and October 2004. All patients had diagnostic magnetic resonance imaging (MRI) preoperatively and computerized tomography (CT) within 24 h post biopsy.

Outcome measures: The diagnostic yield, correlation between preoperative radiological and histological diagnosis, and the associated morbidity and mortality were analysed.

Results: Histological diagnosis was obtained in 31 of the 34 biopsies (91.2%). The preoperative radiological diagnosis was accurate for differentiating neoplastic from non-neoplastic lesion in 28 of 31 cases (90.3%). There was no mortality and morbidity was 7.89%.

Conclusion: Stereotactic biopsy is a minimally invasive procedure with a high diagnostic yield and low morbidity. A definitive histological diagnosis supports the development of an optimal treatment plan in this difficult group of patients.