Botulinum toxin A and chronic back pain: a randomized, double‐blinded study. (Walter Reed Army Medical Center, Washington, DC) Neurology. 2001;56:1290–1293.

This study investigated the efficacy of botulinum toxin A in chronic low back pain and associated disabilities. Thirty‐one consecutive patients with chronic low back pain who met the inclusion criteria were studied. Each patient's baseline level of pain and degree of disability was documented using the visual analogue scale (VAS) and the Oswestry Low Back Pain Ques‐ tionnaire (OLBPQ). The authors reevaluated the patients at 3 and 8 weeks (VAS) and 8 weeks (OLBPQ). At 3 weeks, 11 of the 15 patients who received botulinum toxin (73.3%) had> 50% pain relief versus 4 of 16 in the saline group. At weeks, 9 of 15 in the botulinum toxin group and 2 of 16 in the saline group had relief. Repeat OLPBPQ at 8 weeks showed improvement in 10 of 15 in the botulinum toxin group versus 3 of 16 in the saline group. No patient experienced side effects. Conclude that paravertebral administration of botulinum toxin A in patients with chronic low back pain relieved pain and improved function at 3 and 8 weeks after treatment.Comment by Miles Day, M.D. This study evaluates the use of botulinum toxin A in the treatment of myofascial pain in patients with chronic low back pain. It's conclusion is “Paravertebral administration of botulinum toxin A in patients with chronic low back pain relieved pain and impoved function at 3 and 8 weeks after treatment”. While the results of this study are promising I agree with the authors that the conclusion should be regarded with caution because the sample size of patients studied was small. My main criticism is in the selection criteria the authors use in this criteria. As stated in the study six of the patients had a history of disc disease and three had had discectomies five to eighteen years prior to the study. As we in the pain field know, continuing pain after previous surgery can be secondary to multiple causes including disc disease, epidural scaring, myofascial pain, and facet disease. These patients sometime have a hard time delineating the amount of pain that is being generated from each one of these potential causes of ongoing pain. The results of this study may have been better if the inclusion criteria eliminated patients with multiple pain generators and only included patients with myofacial pain.