Persistent Low Back Pain
http://www.100md.com
《新英格兰医药杂志》
To the Editor: Carragee (May 5 issue)1 states that "radiofrequency ablation . . . was ineffective in one randomized trial" but does not discuss flaws in the methods and procedures of that study.2 In his comments on a double-blind, randomized trial reported by van Kleef and colleagues, Carragee notes that radiofrequency "showed a moderate effect . . . which lasted only four weeks" but does not mention that, as compared with the placebo group, the group treated with zygapophyseal joint denervation showed statistically significant improvement at 3, 6, and 12 months.3
Our opinion of minimally invasive treatment options (injections and neuroablation procedures) differs from Carragee's. The potential advantages of these treatments include low risk–benefit ratios and relatively low costs. We fully acknowledge that more clinical studies are needed to support this new and promising approach for low back pain.
Aneesh K. Singla, M.D., M.P.H.
Brigham and Women's Hospital
Boston, MA 02115
asingla@partners.org
Milan Stojanovic, M.D.
Steven Barna, M.D.
Massachusetts General Hospital
Boston, MA 02114
References
Carragee EJ. Persistent low back pain. N Engl J Med 2005;352:1891-1898.
Dreyfuss P, Baker R, Leclaire R, et al. Radiofrequency facet joint denervation in the treatment of low back pain: a placebo-controlled clinical trial to assess efficacy. Spine 2002;27:556-557.
van Kleef M, Barendse GA, Kessels A, Voets HM, Weber WE, de Lange S. Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain. Spine 1999;24:1937-1942.
To the Editor: In his review article on low back pain, Carragee advocates the use of amitriptyline but does not mention anything about weight loss. A significant reduction in disability related to low back pain has been noted with reduction of weight in obese patients, from a group mean of 132 kg to 92 kg.1 Though not mentioned as an adverse effect in Table 1 of the article, amitriptyline causes weight gain. Cyclobenzaprine is an effective treatment for insomnia and nocturnal pain from paraspinal muscle spasm in the low back.2
Michael A. Meyer, M.D.
Jacobs Neurological Institute
Buffalo, NY 14203
michaelandrewmeyer@yahoo.com
References
Melissas J, Kontakis G, Volakakis E, Tsepetis T, Alegakis A, Hadjipavlou A. The effect of surgical weight reduction on functional status in morbidly obese patients with low back pain. Obes Surg 2005;15:378-381.
Toth PP, Urtis J. Commonly used muscle relaxant therapies for acute low back pain: a review of carisoprodol, cyclobenzaprine hydrochloride, and metaxalone. Clin Ther 2004;26:1355-1367.
Dr. Carragee replies: Dr. Singla and colleagues note that although one randomized trial showed no benefit, a second blinded, randomized trial, by van Kleef et al., showed increased improvement in the group treated with radiofrequency ablation for supposed facet-joint pain.1 Unfortunately, the randomization in that study failed to distribute confounding factors evenly because of very small numbers (only 31 subjects were recruited), and the sham-treatment group had pain that lasted two years longer than that in the radiofrequency-ablation group and had worse functional disability (representing a difference of 7 points, at baseline, on the Oswestry Disability Index). Despite these baseline biases predisposing to better results in the treatment group, by eight weeks there was no difference in function according to the Waddell method and a minimal difference in mean scores (less than 2 points). More recently, in a much larger, multicenter, randomized trial, van Wijk et al. failed to show even these small differences between radiofrequency ablation and sham treatment.2 In both of these studies, the diagnosis of facet-joint pain was made on the basis of pain relief with an anesthetic injection at the facet joint. It is possible that this screening method resulted in the inclusion of subjects who did not have true facet-joint pain and thus might account for the lack of efficacy. However, it may be that the procedure is relatively ineffective even in subjects with true facet-joint pain.
Dr. Meyer notes that an uncontrolled clinical trial showed that morbidly obese subjects who lost 40 kg after bariatric surgery had a decrease in functional disability. Even in the absence of higher levels of evidence, weight loss in this setting seems a prudent recommendation. Whether small weight-control differences that are hypothetically achieved by avoiding amitriptyline will have any effect is unknown. To my knowledge, there are no randomized trials comparing cyclobenzaprine and amitriptyline. Both agents appear to have moderate efficacy in chronic low back pain.
Eugene J. Carragee, M.D.
Stanford University School of Medicine
Stanford, CA 94305
carragee@stanford.edu
References
van Kleef M, Barendse GA, Kessels A, Voets HM, Weber WE, de Lange S. Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain. Spine 1999;24:1937-1942.
van Wijk RM, Geurts JW, Wynne HJ, et al. Radiofrequency denervation of lumbar facet joints in the treatment of chronic low back pain: a randomized, double-blind, sham lesion-controlled trial. Clin J Pain 2005;21:335-344.
Our opinion of minimally invasive treatment options (injections and neuroablation procedures) differs from Carragee's. The potential advantages of these treatments include low risk–benefit ratios and relatively low costs. We fully acknowledge that more clinical studies are needed to support this new and promising approach for low back pain.
Aneesh K. Singla, M.D., M.P.H.
Brigham and Women's Hospital
Boston, MA 02115
asingla@partners.org
Milan Stojanovic, M.D.
Steven Barna, M.D.
Massachusetts General Hospital
Boston, MA 02114
References
Carragee EJ. Persistent low back pain. N Engl J Med 2005;352:1891-1898.
Dreyfuss P, Baker R, Leclaire R, et al. Radiofrequency facet joint denervation in the treatment of low back pain: a placebo-controlled clinical trial to assess efficacy. Spine 2002;27:556-557.
van Kleef M, Barendse GA, Kessels A, Voets HM, Weber WE, de Lange S. Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain. Spine 1999;24:1937-1942.
To the Editor: In his review article on low back pain, Carragee advocates the use of amitriptyline but does not mention anything about weight loss. A significant reduction in disability related to low back pain has been noted with reduction of weight in obese patients, from a group mean of 132 kg to 92 kg.1 Though not mentioned as an adverse effect in Table 1 of the article, amitriptyline causes weight gain. Cyclobenzaprine is an effective treatment for insomnia and nocturnal pain from paraspinal muscle spasm in the low back.2
Michael A. Meyer, M.D.
Jacobs Neurological Institute
Buffalo, NY 14203
michaelandrewmeyer@yahoo.com
References
Melissas J, Kontakis G, Volakakis E, Tsepetis T, Alegakis A, Hadjipavlou A. The effect of surgical weight reduction on functional status in morbidly obese patients with low back pain. Obes Surg 2005;15:378-381.
Toth PP, Urtis J. Commonly used muscle relaxant therapies for acute low back pain: a review of carisoprodol, cyclobenzaprine hydrochloride, and metaxalone. Clin Ther 2004;26:1355-1367.
Dr. Carragee replies: Dr. Singla and colleagues note that although one randomized trial showed no benefit, a second blinded, randomized trial, by van Kleef et al., showed increased improvement in the group treated with radiofrequency ablation for supposed facet-joint pain.1 Unfortunately, the randomization in that study failed to distribute confounding factors evenly because of very small numbers (only 31 subjects were recruited), and the sham-treatment group had pain that lasted two years longer than that in the radiofrequency-ablation group and had worse functional disability (representing a difference of 7 points, at baseline, on the Oswestry Disability Index). Despite these baseline biases predisposing to better results in the treatment group, by eight weeks there was no difference in function according to the Waddell method and a minimal difference in mean scores (less than 2 points). More recently, in a much larger, multicenter, randomized trial, van Wijk et al. failed to show even these small differences between radiofrequency ablation and sham treatment.2 In both of these studies, the diagnosis of facet-joint pain was made on the basis of pain relief with an anesthetic injection at the facet joint. It is possible that this screening method resulted in the inclusion of subjects who did not have true facet-joint pain and thus might account for the lack of efficacy. However, it may be that the procedure is relatively ineffective even in subjects with true facet-joint pain.
Dr. Meyer notes that an uncontrolled clinical trial showed that morbidly obese subjects who lost 40 kg after bariatric surgery had a decrease in functional disability. Even in the absence of higher levels of evidence, weight loss in this setting seems a prudent recommendation. Whether small weight-control differences that are hypothetically achieved by avoiding amitriptyline will have any effect is unknown. To my knowledge, there are no randomized trials comparing cyclobenzaprine and amitriptyline. Both agents appear to have moderate efficacy in chronic low back pain.
Eugene J. Carragee, M.D.
Stanford University School of Medicine
Stanford, CA 94305
carragee@stanford.edu
References
van Kleef M, Barendse GA, Kessels A, Voets HM, Weber WE, de Lange S. Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain. Spine 1999;24:1937-1942.
van Wijk RM, Geurts JW, Wynne HJ, et al. Radiofrequency denervation of lumbar facet joints in the treatment of chronic low back pain: a randomized, double-blind, sham lesion-controlled trial. Clin J Pain 2005;21:335-344.