Tuveson B, Leffler AS, Hansson P: Ondansetron, a 5HT3-antagonist, does not alter dynamic mechanical allodynia or spontaneous ongoing pain in peripheral neuropathy. Clin. J. Pain DOI: 10.1097/AJP.0b013e31820215c5 (2010) (Epub ahead of print).
A descending facilitatory drive mediated through spinal serotonin type 3 (5HT3) receptors has been implicated in the maintenance of persistent pain. Therefore, studies have suggested a potential role of 5HT3 receptor antagonism in the relief of chronic pain, including neuropathic pain. Ondansetron is a 5HT3, antagonist and the effect of a single intravenous infusion of 8?mg ondansetron was studied in a randomized, double-blind, placebo-controlled trial in patients with painful peripheral neuropathy. In this study, no effect of ondansetron on ongoing pain or brush-evoked pain was seen. This suggests that facilitation through 5HT3 receptors did not mediate ongoing pain and dynamic mechanical allodynia in this patient group.
Holbech JV, Otto M, Bach FW, Jensen TS, Sindrup SH: The anticonvulsant levetiracetam for the treatment of pain in polyneuropathy: a randomized, placebo-controlled, cross-over trial. Eur. J. Pain DOI: 10.1016/j.ejpain.2010.11.007 (2010) (Epub ahead of print).
Levetiracetam, the S-enantiomer of α-ethyl-2-oxo-1-pyrrolidine acetamide, is a novel antiepileptic drug that is believed to act by binding to the synaptic vesicle protein SV2A in the brain and spinal cord, thereby inhibiting presynaptic neurotransmitter release. In animal models and human case reports, levetiracetam has been suggested to have an effect on neuropathic pain. In this randomized, double-blind, placebo-controlled, crossover trial, there was no effect of levetiracetam 3000 mg/day compared with placebo in patients with painful polyneuropathy. The results of this study are in line with other randomized controlled trials and indicate that levetiracetam has no clinically relevant effect on various neuropathic pain conditions.
Coderre TJ: Complex regional pain syndrome: what‘s in a name? J. Pain 12(1), 2–12 (2011).
This is a very interesting review of complex regional pain syndrome (CRPS), which analyzes the historical steps that have led us to the present lack of understanding for the biomedical basis of this devastating pain syndrome. Coderre looks back at the publications of Evans and Foise who first proposed mechanisms for ‘reflex sympathetic dystrophy‘. Perhaps Foise was correct, and CRPS is a manifestation of “injury-reperfusion syndrome” and is not based upon primary nervous system abnormalities. Perhaps the propinquity of major nerves in the extremities to the arterial supply of the limb can explain what used to be called causalgia: it is not the nerve injury but the blood vessel injury that leads to CRPS II. The author does not have an answer to his suggestion, but he certainly does point the way towards a new approach for investigating CRPS. This is an innovative and provocative article that deserves widespread attention.
Hong SH, Roh SY, Kim SY et al.: Change in cancer pain management in Korea between 2001 and 2006: results of two nationwide surveys. J. Pain Symptom Manage. 41(1), 93–103 (2011).
In 2001, the Korean Society of Hospice and Palliative Care disseminated a cancer pain management guideline and undertook a national survey of patients with cancer to determine prevalence and severity of pain in the same year. In this article, the authors report on a follow-up survey completed in 2006 and the differences over the 5 years since the first survey. Overall, 7565 patients were enrolled from 72 cancer hospitals in the 2001 cancer pain survey and 7245 patients were enrolled from 63 cancer hospitals in the 2006 cancer pain survey. The overall prevalence of cancer pain and the percentage of patients reporting a negative pain management index (a crude measure of adequate prescription) were significantly decreased in the 2006 cancer pain survey compared with the 2001 cancer pain survey (44.9 vs 52.1%, p < 0.0001; and 41.6 vs 45.0%, p = 0.0005, respectively). Despite the improvements, in 2006, 25.8% of the patients surveyed who had severe pain did not have any prescribed analgesics and 47.4% of patients reported that their physicians did not adjust the prescribed analgesics properly. The authors recommend further efforts towards educational programs for cancer pain directed at physicians who care for cancer patients.
Murthy NS, Maus TP, Behrns CL: Intraforaminal location of the great anterior radiculomedullary artery (artery of Adamkiewicz): a retrospective review. Pain Med. 11(12), 1756–1764 (2010).
A retrospective review was undertaken of 248 thoracic and lumbar spinal angiograms performed over a 10?year period. The side, level and intraforaminal location of the artery of Adamkiewicz at the midpedicular level was evaluated. Within these, 120 radiculomedullary arteries were able to be clearly evaluated. The artery was located in the upper third of the foramen in 88%, the middle third in 9% and the lower third in 2% of cases. The radiculomedullary artery was found on the left side in 83% of angiograms, while 92% were located between T8 and L1, most commonly at T10 (28%). The authors conclude that the safest position for a transforaminal epidural needle placement may be in an inferior and slightly posterior position within the foramen.
Plastaras CT, Casey E, Goodman BS, Chou L, Roth D, Rittenberg J: Inadvertent intradiscal contrast flow during lumbar transforaminal epidural steroid injections: a case series examining the prevalence of intradiscal injection as well as potential associated factors and adverse events. Pain Med. 11(12), 1765–1773 (2010).
A retrospective case series of 8132 lumbar transforaminal epidural steroid injections performed over an 8?year period was carried out. Injections were performed between levels L2–S1 under fluoroscopic guidance. A total of 15 cases of inadvertent intradiscal contrast flow were identified (0.17%). All patients received prophylactic antibiotics after inadvertent disk injection, and no infectious or other complications were identified. Intradiscal placement of the needle tip was not always required for intradiscal contrast flow to be observed. The authors conclude that the prevalence of intradiscal contrast injection is low, and may be associated with ipsilateral foraminal stenosis.
Wong MR, Del Rosso P, Heine L et al. : An outbreak of Klebsiella pneumoniae and Enterobacter aerogenes bacteremia after interventional pain management procedures, New York City, 2008. Reg. Anesth. Pain Med. 35(6), 496–499 (2010).
The New York City Department of Health and Mental Hygiene carried out an investigation of an outpatient pain treatment facility subsequent to notification of two cases of Klebsiella pneumoniae bloodstream infections in patients having undergone percutaneous pain treatment injections. The records of a total of 54 patients who had undergone procedures within 4 days of the index cases were reviewed. Of these, four laboratory-confirmed cases and five suspected cases of bacteremia were identified. All of these patients had received sacroiliac joint injections. Multiple breaches of infection control were noted in the investigation, including the reuse of single?dose medication vials for multiple patients.
Plancarte R, Guajardo-Rosas J, Reyes-Chiquete D et al.: Management of chronic upper abdominal pain in cancer: transdiscal blockade of the splanchnic nerves. Reg. Anesth. Pain Med. 35(6), 500–506 (2010).
A prospective, longitudinal study of 109 patients with unresectable upper abdominal or lower esophageal neoplasms was carried out. These patients underwent posterior approach transdiscal splanchnic nerve blocks under computed tomography guidance. At 1 week postintervention, visual analog scale pain scores decreased from 6.1 ± 2.4, with an average of 102.4 mg/day of morphine consumed, to 2.7 ± 2.4, with an average of 53.3 mg/day of morphine consumed. Pain relief persisted throughout the 1?year follow-up period or until death. Minor adverse events such as diarrhea and hypotension were frequent, while transient paraparesis was identified in one patient. This single-needle technique is advocated as an alternative to antecrural celiac plexus nerve block or a two-needle retrocrural approach to splanchnic nerve block.
Hejtmanek MR, Harvey TD, Bernards CM: Measured density and calculated baricity of custom-compounded drugs for chronic intrathecal infusion. Reg. Anesth. Pain Med. 36(1), 7–11 (2011).
This is the first study to look at the relationship between concentration and density of drugs injected intrathecally. The data obtained may help to explain some of the vagaries of intrathecal drug administration and the role of the catheter tip location in the determination of efficacy. However, combinations of drugs, as often used clinically, were not evaluated. Much more research needs to be performed on this aspect of intrathecal drug administration, both for pain relief and other aspects of this drug delivery technology. However, this paper is a good start.
Passik SD, Messina J, Golsorkhi A, Xie F: Aberrant drug-related behavior observed during clinical studies involving patients taking chronic opioid therapy for persistent pain and fentanyl buccal tablet for breakthrough pain. J. Pain Symptom Manage. 41(1), 116–125 (2011).
This paper describes a retrospective analysis of data taken from five clinical trials that evaluated fentanyl buccal tablets (FBTs) for breakthrough pain associated with neuropathic, low back or other chronic pain diagnoses. All patients in these trials were opioid tolerant. The authors examined the frequency of aberrant drug behaviors such as abuse, overdose or missing doses that occurred during these trials. In total, 1160 patients were entered into the trials and aberrant behaviors that were related to FBTs were found in 124 (11%) of these patients. In a further 68 (6%) patients, aberrant behaviors (e.g., seeking prescriptions from other sources) unrelated to FBTs were recorded. Abuse was found in only ten (<1%) patients, although 12 (1%) had an event consistent with opioid overdose and 18 (<2%) had a positive urine drug screening for an illicit substance. Aberrant behaviors were more frequent in men and patients under 50 years of age. The authors conclude that although aberrant behaviors were infrequent, their data are drawn from the context of a closely monitored clinical trial. The frequency of such events in routine clinical care is not known, but may well be higher than those reported here.
Financial & competing interests disclosure
N Finnerup has received honoraria and research support from Grünenthal. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
No writing assistance was utilized in the production of this manuscript.