Intraoperative Spinal Nerve Root Injuries during Surgery for Degenerative Low Back Disease

Abstract

‐ Abstract ‐ Study Design : A retrospective study Objective : To analyze incidence, causes and prognosis of the spinal nerve root injury during the degenerative low back surgery. Summary of Literature Review : There were very few studies about intraoperative spinal nerve root injuries during low back surgery. Materials and Methods : Six hundred and twenty seven patients underwent degenerative low back surgery from Jan 1990 to Jan 2001 were included in this study. All patients were operated on by the first author and operation records made by the author himself were reviewed. Eight cases of intraoperativ e spinal nerve root injury were identified and causes and level of injuries, preoperative diagnosis, types of surgery and follow-up clinical results were analyzed. Results : Eight cases of nerve root injury were developed during 5 posterior laminotomies for discectomy and 3 instrumentation and fusion. Spinal nerve root injuries were caused by Kerrison punch in 4 cases, pituitary forcep in 2, rongeur in 1, and not certain but probably by Kerrison punch in 1 case. The levels of injuries were 5th lumbar nerve root in 4 cases, and 1st sacral nerve root and 2nd lumbar nerve root in 1 case respectively. Two cases had sacral nerve rootlet injury with paramedian dural tear but the level of root injury was uncertain. Six of 8 patients had symptoms. There were sensory loss in 4 patients, pain in 2, and one patient had both sensory loss and loss of big toe extension power. Neurological symptoms were not improved throughout the follow-up period, but 2 patients who had pain were resolved their symptoms by 3 months. Conclusions : Incidental spinal nerve root injury occurred in 1.3 percentage of the patients who underwent low back surgery. Half of them had neurologic symptoms and they showed poor prognosis. However motor deficit was relatively uncommon and it might be related to the anatomical characteristics of spinal nerve root.