Rados I, Sakic K, Fingler M, Kapural L. Efficacy of interlaminar vs transforaminal epidural steroid injection for the treatment of chronic unilateral radicular pain: prospective, randomized study. Pain Med. 12, 1316–1321 (2011).
A total of 64 patients with chronic lumbar radicular pain due to lumbar disc herniation were randomized to interlaminar (IL) versus transforaminal (TF) epidural steroid injection under fluoroscopic guidance. Eligible patients had a pain score of 5 or greater, failed 6 weeks of conservative therapy and did not display myelopathic symptoms. All patients had either L4–L5 or L5–S1 pathology. Injections were performed at the appropriate dermatomal level based on symptoms as well as MRI and/or electromyography results. IL injections were performed with 80 mg of methylprednisolone combined with 8 cc of 0.5% lidocaine. TF injections were performed with 40 mg of methlyprednisolone with 3 cc of 0.5% lidocaine. A series of three injections were performed 2 weeks apart. No anticonvulsants or antidepressants were allowed, and tramadol was provided for breakthrough pain.
Pain scores improved significantly in both the IL (7.36 reduced to 4.0) and TF (6.72 reduced to 3.8) groups, but were not significantly different between these groups. Functional capacity as measured on the Oswestry scale also improved in both the IL (52 reduced to 39%) and TF (53 reduced to 38%) groups and were not significantly different from each other. The authors conclude that both techniques provide significant improvement in both pain relief and functional capacity, but without any significant difference between the two injection techniques. It is noted that the TF group received half the steroid dose of the IL group.
– Written by Michael Erdek
Prochazka J, Hejci A, Prochazkova L. Intrathecal midazolam as supplementary analgesia for chronic lumbar pain – 15 years‘ experience. Pain Med. 12, 1309–1315 (2011).
A prospective, open-label study was carried out over a 15-year period and 500 total administrations of intrathecal midazolam in patients with chronic low back pain (81 administrations) or failed back surgery syndrome (419 administrations). Single-shot administrations of initially 2 mg and then a range of up to 5 mg at least 4 weeks apart were given to patients who had failed first local interventions and then epidural steroids. Preservative-free midazolam was used in a volume of up to 3 ml. Outcome assessment was based on patient questionnaires given on subsequent patient visits. A positive outcome was considered to be at least 50% reduction in pain with both improved quality of life and improved functional condition.
Results showed that analgesic effect was achieved for a mean of 9.7 weeks, and lasted 4 weeks or more in 65% of patients. No relief of pain was found in 13% of subjects. An average of 1–3 months‘ relief was achieved after a single-shot injection. Approximately 30% of patients reported drowsiness subsequent to the injection; headache and nausea were reported in <2% of subjects. No patients displayed symptoms of neurotoxicity, including development of myelopathic or new neuropathic symptoms.
– Written by Michael Erdek
Taminen T, Kuusalo L, Lehtinen L et al. Psychiatric (axis I) and personality (axis II) disorders in patients with burning mouth syndrome or atypical facial pain. Scand. J. Pain 2, 155–160 (2011).
Burning mouth syndrome and atypical facial pain are relatively common but incompletely understood chronic pain conditions mainly affecting women. In this thoroughly performed study, it was found that psychiatric disorders (major depression, persistent social phobia and neurotic, fearful and obsessive–compulsive personality characteristics) were common in these patients and often preceded the onset of chronic idiopathic orofacial pain. Many patients also had one or more other pain conditions. The authors suggest that these finding can be understood as a shared vulnerability to both chronic pain and specific psychiatric disorders in these patients, possibly mediated by dysfunctional brain dopamine activity.
– Written by Nanna B Finnerup
Wu CL, Raja SN. Treatment of acute postoperative pain. Lancet 377, 2215–2225 (2011).
This is an up-to-date review of the current knowledge of the pathophysiology and management of acute postoperative pain. The authors emphasize that postoperative pain continues to be undermanaged. The paper highlights recent developments in the understanding of postoperative pain and acute opioid-induced hyperalgesia and discusses potential risk determinants of persistent postsurgical pain. The use of specific analgesic techniques such as regional analgesia and new analgesic agents are discussed, as well as patient outcomes.
– Written by Nanna B Finnerup
Smith HS. The metabolism of opioid agents and the clinical impact of their active metabolites. Clin. J. Pain 27, 824–838 (2011).
Although this article does not describe any new research findings, it very effectively characterizes the opioids in clinical use today, describes their metabolites and the interactions of the drugs and their metabolites with coadministered drugs. Active metabolites of opioid analgesics can be the source of significant analgesia and be responsible for many of the adverse events associated with these drugs. Since most of the opioids are metabolized by the P450 enzymes in the liver, the polymorphisms in CYP450 enzymes may have a major impact upon metabolism and adverse events. The ideal opioid agent would be orally administered, would not be extensively metabolized, would not affect CYP450 metabolism and would not have active metabolites, but such a drug has not yet been developed. Those who prescribe opioids for pain management could improve their patient management skills by understanding the metabolism of these drugs. The use of meperidine would be curtailed if the prescribing public were knowledgeable about its metabolite, normeperidine, which has a much longer half-life than its parent drug and is quite neurotoxic. This review article is a treasure trove of information that is easily accessed by the practitioner.
– Written by John D Loeser
Financial & competing interests disclosure
NB Finnerup receives research funding from the Europain Investigational Medicines Initiative, which is a public–private partnership between the pharmaceutical industry and the European Union. NB Finnerup has also received research funding from Grünenthal and served as a consultant for Astellas, Grünenthal and Pfizer. 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.