Local denervation of lumbar paraspinal muscles may not be used as a criterion for the effectivity of radiofrequency lesions of the zygapophyseal joints.

Autor: Barendse, Gerard A.M., Spaans, Frank, Stomp-Van Den Berg, Suzanne, Weber, Wilhelm E.J., Kessels, Alfons, Van Kleef, Maarten
Předmět:
Zdroj: Pain Clinic; 2001, Vol. 13 Issue 2, p125-131, 7p
Abstrakt: A treatment option in a selected group of patients with chronic non-specific low back pain is percutaneous radiofrequency denervation of lumbar zygapophyseal joints (RDLZJ). These joints and the lumbar paravertebral musculature are innervated by the dorsal rami of the lumbar spinal nerves. It has been stated that the effectiveness of the procedure can be deduced from the finding of electromyographic signs of denervation in the paraspinal muscles. This study was designed to test the following: Does RDLZJ cause spontaneous muscle fibre activity of the paraspinal muscles? Is pain relief after a RDLZJ correlated with the presence of spontaneous activity in the paraspinal muscles? In a prospective observer-blind study, twenty-eight patients with a history of at least one year of chronic low back pain were selected on the basis of a positive response to a diagnostic nerve blockade and subsequently randomly assigned to one of two treatment groups. Each patient in the RF treatment-group (14 patients) received an 80°C radiofrequency lesion of the medial branch of the dorsal ramus of the segmental nerve roots L3, L4 and L5. Patients in the control group (n = 14) underwent an exactly similar procedure, without using a radiofrequency current. Three weeks after the treatment, needle electromyography of the paravertebral muscles was performed by an experienced clinical neurophysiologist. Before and 8 weeks after treatment of pain, all patients were assessed with a pain diary (by means of Visual Analogue Scale, VAS score) and 12 months after the procedure there was an evaluation of pain scores of patients who were considered as success patients. Electromyography of the paraspinal muscles showed no significant differences between the 'lesion-group' and the 'control group'. There was also no relation between 'success-patients' in the lesion group and the presence of signs of denervation in the paraspinal muscles. As the association between the pain relief after RDLZJ and the presence of electromyographic signs of denervation in the paraspinal muscles is weak, this parameter is of limited use to evaluate therapy effects of RDLZJ. [ABSTRACT FROM AUTHOR]
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