Preoperative full-length standing radiographs and revision rates in lumbar degenerative scoliosis.

Abstract

OBJECTIVE Full-length (36-inch) standing spine radiographs are commonly used by spine surgeons to evaluate patients with lumbar degenerative scoliosis (LDS). Despite this practice, the impact of these images on preoperative decision making and the rate of revision surgery has not been analyzed. The purpose of this study is to determine if preoperative full-length standing spine radiographs improve surgical decision making by decreasing the rate of revision surgery in patients with LDS. METHODS From the Health Care Service Corporation administrative claims database, the authors identified patients 50-80 years of age with LDS who had undergone surgery including posterior lumbar decompression and fusion over 2-6 levels and with at least 5 years of continuous coverage after the index surgery. Patients were stratified into the following groups, according to the preoperative imaging studies performed within 6 months before their index surgery: lumbar spine MRI studies only, lumbar spine MRI studies and standard lumbar spine radiographs, CT myelograms, and full-length standing spine radiographs. Survival analysis was performed with the occurrence of a revision within 5 years of the index surgery as the outcome of interest. RESULTS A total of 411 patients were included in the study after applying the inclusion and exclusion criteria. Revision surgery within 5 years after the index procedure was most frequent in the patients with preoperative MRI only (41.8%), followed by the patients with a CT myelogram (30.4%) and those with MRI and standard radiographs (24.8%). The lowest revision rate was seen among those with long-cassette standing radiographs (11.1%). Patients whose preoperative evaluation included full-length standing radiographs (OR 0.353, p = 0.034) and MRI studies plus radiographs (OR 0.650, p = 0.022) were less likely to require revision surgery at 5 years after the index procedure. CONCLUSIONS An assessment of standing alignment using full-length (36-inch) standing radiographs may be beneficial in reducing the risk of revision surgery in patients with lumbar scoliosis. This observation was not limited to patients with large curves or substantial deformity.