L5 nerve root decompression after malunion of surgically managed vertically unstable pelvic ring injuries.

We describe the outcomes of late decompression of the L5 nerve root after malunion of surgically managed pelvis injuries. Four patients underwent decompression of the L5 nerve root. Surgery included hemilaminotomy with facetectomy at L5-S1 followed by decompression of the L5 nerve root laterally from the surrounding displaced sacral ala. L5-S1 fusion was not performed. Radiographs and Oswestry Disability Index (ODI) scores were obtained for each patient at latest follow-up. In all patients, adequate decompression required removal of bone to the anterior aspect of the sacral ala inferiorly to the level of the superior endplate of S1, and there was resolution of L5 radicular pain. Late decompression of the proximal course of the L5 nerve root provided pain relief without resultant radiographic pelvis or L5-S1 instability.