Neural Complications of Surgery for Adolescent Idiopathic Scoliosis

Introduction: We report on neural complications in a prospective cohort study of 1000 patients undergoing spinal fusion and instrumentation for adolescent idiopathic scoliosis.

Methods: Records were reviewed of the first 1000 patients in the Prospective Pædiatric Scoliosis Study undertaken by the Spinal Deformity Study Group.

Results: There were 9 neural complications. There were 4 cerebrospinal fluid leaks, one of which required dural repair, and none of which demonstrated intraoperative neuromonitoring changes or had postoperative clinical sequelæ. There were 3 nerve root injuries. In one, a positional compression femoral neurapraxia resolved over 6 weeks. The others were L4 neurapraxias despite lowest instrumented vertebra L1 and normal neuromonitoring; both resolved spontaneously by 3 months follow-up. There were 2 spinal cord injuries. Common themes included > 70º thoracic scoliosis, > 80% curve correction, normal intraoperative neuromonitoring, and imaging showing no implant malposition. Both resolved spontaneously by 4 months after operation.

Conclusions: Our overall neural complication rate was 0.9%. If cerebrospinal fluid leak is eliminated, as it implies intradural entry but not direct neural injury, our rate is 0.5%. Our findings are consistent with other studies in the North American Literature, including multiple reports from the Scoliosis Research Society. The cases of spinal cord injury appear to have been late onset secondary to spinal cord stretch after near total correction of large curves, providing a cautious reminder of the power of modern instrumentation techniques. The L4 neurapraxias may also represent a stretch phenomenon, as they were remote from the operative site. None of the neural injuries was permanent. Our results reaffirm that surgical treatment of adolescent idiopathic scoliosis has a low neural complication rate.