LOCAL DENERVATION ATROPHY OF PARASPINAL MUSCLES IN POSTOPERATIVE FAILED BACK SYNDROME

Impairment and disability after back surgery is a common diagnostic an d therapeutic problem. For the most part the reasons are unclear. Of 1 78 patients who had undergone laminectomies 2-5 years earlier, 14 pati ents with good recovery and 21 patients with poor recovery but no evid ence of restenosis on computed tomography were selected by the Oswestr y index. According to radiologic, neurophysiologic, and muscle biopsy evidence most patients (13 of 15 studied) suffering from the severe po stoperative failed back syndrome had dorsal ramus lesions in one or mo re segments covered by the scar and local paraspinal muscle atrophy at the corresponding segments. Disturbed back muscle innervation and los s of muscular support leads to the disability and increased biomechani cal strain and might be one important cause to the failed back syndrom e. It may be possible to develop operating techniques that save back m uscle innervation better than the usual ones.