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BMJ 2003 Mar 22;326(7390):635-9
Magill Department of Anaesthesia, Imperial College London, Chelsea and Westminster Hospital, London SW10 9JP. aholdcro@ic.ac.uk
[Medline record in process]
PMID: 12649239, UI: 22535213
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Br J Anaesth 2003 Apr;90(4):467-73
Department of Anaesthesiology, Division of Pain Therapy, University of Bern, Inselspital, CH-3010 Bern, Switzerland. Laboratory for Experimental Pain Research, Center for Sensory-Motor Interaction, University of Aalborg, Aalborg, Denmark.
BACKGROUND: Despite extensive use, different aspects of the pharmacological action of epidural fentanyl have not been clarified. We applied a multi-modal sensory test procedure to investigate the effect of epidural fentanyl on segmental spread, temporal summation (as a measure for short-lasting central hyperexcitability) and muscle pain. METHODS: Thirty patients received either placebo, 50 or 100 micro g single dose of fentanyl epidurally (L2-3), in a randomized, double-blind fashion. Heat pain tolerance thresholds at eight dermatomes from S1 to fifth cranial nerve (assessment of segmental spread), pain threshold to transcutaneous repeated electrical stimulation of the sural nerve (assessment of temporal summation) and pain intensity after injection of hypertonic saline into the tibialis anterior muscle (assessment of muscle pain) were recorded. RESULTS: Fentanyl 100 micro g, but not 50 micro g, produced analgesia to heat stimulation only at L2. Surprisingly, no effect at S1 was detected. Both fentanyl doses significantly increased temporal summation threshold and decreased muscle pain intensity. CONCLUSIONS: The findings suggest that a single lumbar epidural dose of fentanyl should be injected at the spinal interspace corresponding to the dermatomal site of pain. Increased effect on L2 compared with S1 suggests that drug effect on spinal nerve roots and binding to opioid receptors on the dorsal root ganglia may be more important than traditionally believed for the segmental effect of epidurally injected fentanyl. Epidural fentanyl increases temporal summation threshold and could therefore contribute to prevention and treatment of central hypersensitivity states. I.M. injection of hypertonic saline is a sensitive technique for detecting the analgesic action of epidural opioids. Br J Anaesth 2003; 90: 467-73
PMID: 12644419, UI: 22530822
Clin J Pain 2002 Nov-Dec;18(6 Suppl):S163-8
The Crown Institute, Toronto, Ontario, Canada. Freund@crowninstitute.com
Whiplash-associated disorders (WADs) occur as a result of trauma and are often due to motor vehicle accidents and sports injuries. Cervical injury is attributed to rapid extension followed by neck flexion. The exact pathophysiology of WAD is uncertain but probably involves some degree of aberrant muscle spasms and may produce a wide range of symptoms. Initial treatment of pain associated with whiplash usually includes oral medications, such as muscle relaxants and nonsteroidal anti-inflammatory drugs. However, these agents are limited by potential systemic adverse effects. Some patients with chronic WAD may benefit from radiofrequency neurotomy. A new approach to treatment is the use of botulinum toxin, which acts to reduce muscle spasms. Type A toxin (Botox) has been studied in small trials of patients with WAD and has generally been found to relieve pain and improve range of motion. In addition, recent preliminary data from a small trial showed that type B toxin (Myobloc) produced almost immediate pain relief for most patients with post-whiplash headache. Although botulinum toxin has not been evaluated in large long-term trials, these initial data are promising and suggest a role for this agent in the treatment of WAD. Additional study is needed to identify the subset of patients with WAD who are most likely to respond to treatment with botulinum toxin.
PMID: 12569964, UI: 22457384
Clin J Pain 2002 Nov-Dec;18(6 Suppl):S119-24
225 Victoria Road, Burlingame, California, USA.
The seven botulinum neurotoxin serotypes share less than 50% sequence homology and are immunologically distinct. The neurotoxins inhibit release of the neurotransmitter acetylcholine from the axon terminals of motor neurons, preganglionic sympathetic and parasympathetic neurons, and postganglionic parasympathetic nerves by a multi-step mechanism that differs slightly, but significantly, for each serotype. The inhibition is long lasting but temporary. The resulting muscle paralysis has provided the basis for therapeutic use of botulinum toxin types A and B in a variety of focal dystonias. The safety of the botulinum toxins, when administered focally, has permitted their widespread use in a number of other painful conditions.
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PMID: 12569958, UI: 22457378
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N Engl J Med 2003 Mar 20;348(12):1150-8
Department of Pediatric Hematology/Oncology, Massachusetts General Hospital, Boston, USA.
PMID: 12646672, UI: 22533835
Pain 2002 Dec;100(3):243-8
Department of Pharmacology, College of Medicine, University of Arizona Health Sciences Center, Tucson, AZ 85724, USA.
Spinal antinociception produced by delta 9-tetrahydro-cannabinol (Delta(9)-THC) and other cannabinoid agonists has been suggested to be mediated by the release of dynorphin acting at the kappa opioid receptor. Alternatively, as cannabinoid receptors are distributed appropriately in the pain transmission pathway, cannabinoid agonists might act directly at the spinal level to inhibit nociception, without requiring dynorphin release. Here, these possibilities were explored using mice with a deletion of the gene encoding prodynorphin. Antinociceptive dose-response curves were constructed for spinal Delta(9)-THC and WIN 55,212-2 in prodynorphin knock-out mice and in wild-type littermates. WIN 55,212-2 and Delta(9)-THC were equipotent in the wild-type and prodynorphin knock-out mice. Spinal pretreatment with a kappa opioid receptor antagonist, nor-binaltorphimine (nor-BNI), did not alter the dose-response curves for either WIN 55,212-2 or Delta(9)-THC in prodynorphin knock-out and wild-type mice. However, the same dose of nor-BNI used blocked U50,488H-induced antinociception in both wild-type and prodynorphin knock-out mice, confirming kappa opioid receptor activity. Pretreatment with SR141716A, a cannabinoid receptor antagonist blocked the antinociceptive actions of both WIN 55,212-2 and Delta(9)-THC. These data support the conclusion that antinociception produced by spinal cannabinoids are likely to be mediated directly through activation of cannabinoid receptors without the requirement for dynorphin release or activation of kappa opioid receptors.
PMID: 12467995, UI: 22356978
Spine 2003 Mar 15;28(6):607-15
The Spine Center at Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA. Thom@Hitchcock.org
STUDY DESIGN: Analysis of longitudinal data collected prospectively from patients seen in 27 National Spine Network member centers across the United States. OBJECTIVE: To evaluate the responsiveness of the Oswestry Disability Index, MODEMS scales, and all scales and summary scales of the MOS Short-Form 36 (SF-36) for patients with low back pain/leg symptoms. SUMMARY OF BACKGROUND DATA: The responsiveness of general and condition-specific health status instruments is a key concept for clinicians and scientists. Various authors have explored responsiveness in common surveys used to assess spine patients. Although it is generally believed that condition-specific measures are more responsive to change in the condition under study, in the case of low back pain, most authors agree that further exploration is necessary. METHODS: Patients with diagnoses of herniated disc, spinal stenosis, and spondylosis from the National Spine Network database who completed baseline and 3-month follow-up surveys were analyzed. Patient-provider consensus regarding improvement, worsening, or no change in the condition was selected as the external criterion. Responsiveness was evaluated using ROC curve analysis and effect size calculations. RESULTS: Nine hundred and seventy patients had complete data at baseline and 3 months. At follow-up, 68% of the patients had consensus improvement. Based on ROC analysis, scales assessing pain were significantly more responsive than scales assessing function. There were no significant differences between the condition-specific scales and their equivalent general-health counterpart. The scales with the highest probabilities of correctly identifying patient's improvement were: the condition-specific pain scale from MODEMS (PAIN, ROC = 0.758); the combined pain and function scale from MODEMS (MPDL, ROC = 0.755); the general pain scale from the SF-36 (BP, ROC = 0.753); the combined pain and function scale from the SF-36 (PCS, ROC = 0.745); the condition-specific function measure from the Oswestry (ODI, ROC = 0.723); and the physical function measure from the SF-36 (PF, ROC = 0.721). A similar rank order was typically maintained with effect size calculations. Results were nearly identical in patients with multiple non-spine-related comorbidities and in patients with high degrees of perceived disability. The BP scale was most responsive to worsening of symptoms. CONCLUSION: For studies of patients with low back problems, the general SF-36 may be a sufficient measure of health status and patient function, without the need for additional condition-specific instruments. Pain scales appear to be the most responsive measures in patients with low back pain.
PMID: 12642770, UI: 22529715
Spine 2003 Mar 15;28(6):582-8
University of Alberta, Edmonton, Alberta, Canada. tapio.videman@ualberta.ca
STUDY DESIGN: Retrospective monozygotic twin cohort study. OBJECTIVES: Our goal was to investigate the associations between different spinal MRI findings and current, past year, and lifetime low back pain after adjusting for occupational physical loading, smoking, genetics, and early family influences. SUMMARY OF BACKGROUND DATA: The role of spinal pathology in back symptoms continues to be controversial. METHODS: The study participants consisted of 115 monozygotic male twin pairs 35 to 69 years of age. The qualitatively assessed MRI parameters were as follows: disc height, bulging, herniations, anular tears, osteophytes, spinal stenosis, and endplate changes. Signal intensity was measured quantitatively. RESULTS: After controlling for age, disc height was associated with all back pain variables studied and anular tears with LBP frequency and intensity during the 12 months before imaging. Both were associated with lifetime frequency of low back pain interfering with daily activities, disability, and intensity of the worst lifetime pain episode. Other MRI findings did not explain the various symptom histories. Adjusting for physical loading in the past 12 months increased the associations of anular tears and "low back pain today" and 12-month low back pain parameters. After controlling for genotype and other familial influences, the within-pair differences in disc height and anular tears accounted for 6% to 12% of the total variance in the within-pair differences of low back pain variables. CONCLUSION: These findings raise new questions about the underlying mechanisms of LBP. The sensitivities of the only significant MRI parameters, disc height narrowing and anular tears, are poor, and these findings alone are of limited clinical importance.
PMID: 12642766, UI: 22529711
Spine 2003 Mar 15;28(6):533-40; discussion 540-1
Department of Occupational Medicine, Finnish Institute of Occupational Health, Helsinki, Finland. kaija.karjalainen@occuphealth.fi
STUDY DESIGN: Randomized controlled trial. OBJECTIVES: To investigate the effectiveness and costs of a mini-intervention, provided in addition to the usual care, and the incremental effect of a work site visit for patients with subacute disabling low back pain. SUMMARY OF BACKGROUND DATA: There is lack of data on cost-effectiveness of brief interventions for patients with prolonged low back pain. METHODS: A total of 164 patients with subacute low back pain were randomized to a mini-intervention group (A), a work site visit group (B), or a usual care group (C). Groups A (n = 56) and B (n = 51) underwent one assessment by a physician plus a physiotherapist. Group B received a work site visit in addition. Group C served as controls (n = 57) and was treated in municipal primary health care. All patients received a leaflet on back pain. Pain, disability, specific and generic health-related quality of life, satisfaction with care, days on sick leave, and use and costs of health care consumption were measured at 3-, 6-, and 12-month follow-ups. RESULTS: During follow-up, fewer subjects had daily pain in Groups A and B than in Group C (Group A Group C, = 0.002; Group B Group C, = 0.030). In Group A, pain was less bothersome (Group A Group C, = 0.032) and interfered less with daily life (Group A Group C, = 0.040) than among controls. Average days on sick leave were 19 in Group A, 28 in Group B, and 41 in Group C (Group A Group C, = 0.019). Treatment satisfaction was better in the intervention groups than among the controls, and costs were lowest in the mini-intervention group. CONCLUSIONS: Mini-intervention reduced daily back pain symptoms and sickness absence, improved adaptation to pain and patient satisfaction among patients with subacute low back pain, without increasing health care costs. A work site visit did not increase effectiveness.
PMID: 12642757, UI: 22529702
Spine 2003 Mar 15;28(6):525-31; discussion 531-2
Larvik Fysioterapi, Norway. auro@sensewave.com
STUDY DESIGN: A multicenter, randomized, controlled trial with 1-year follow-up. OBJECTIVES: To compare the effect of manual therapy to exercise therapy in sick-listed patients with chronic low back pain (>8 wks). SUMMARY AND BACKGROUND DATA: The effect of exercise therapy and manual therapy on chronic low back pain with respect to pain, function, and sick leave have been investigated in a number of studies. The results are, however, conflicting. METHODS: Patients with chronic low back pain or radicular pain sick-listed for more than 8 weeks and less than 6 months were included. A total of 49 patients were randomized to either manual therapy (n = 27) or to exercise therapy (n = 22). Sixteen treatments were given over the course of 2 months. Pain intensity, functional disability (Oswestry disability index), general health (Dartmouth COOP function charts), and return to work were recorded before, immediately after, at 4 weeks, 6 months, and 12 months after the treatment period. Spinal range of motion (Schober test) was measured before and immediately after the treatment period only. RESULTS: Although significant improvements were observed in both groups, the manual therapy group showed significantly larger improvements than the exercise therapy group on all outcome variables throughout the entire experimental period. Immediately after the 2-month treatment period, 67% in the manual therapy and 27% in the exercise therapy group had returned to work (P < 0.01), a relative difference that was maintained throughout the follow-up period. CONCLUSIONS: Improvements were found in both intervention groups, but manual therapy showed significantly greater improvement than exercise therapy in patients with chronic low back pain. The effects were reflected on all outcome measures, both on short and long-term follow-up.
PMID: 12642755, UI: 22529700