LAUSR

PURPOSE Intraoperative traction (ITx) has been demonstrated to be a useful adjunct intervention at the time of posterior spinal fusion (PSF) for the treatment of severe neuromuscular scoliosis (NMS) to improve the coronal spinal deformity and pelvic obliquity. The purpose of this study is to determine if preoperative flexibility radiographs can predict the amount of spinal deformity and pelvic obliquity correction at final follow-up. METHODS This was a retrospective analysis of a single-surgeon series who underwent PSF to the pelvis with adjunct ITx for NMS. Database query identified 76 NMS patients, of which 41 met inclusion criteria. Demographic, radiographic and operative data were analyzed. RESULTS Of the 41 study patients, 56% (n = 23) were male and mean age at surgery was 13.6 years. Mean follow-up of 4.1 years (minimum follow-up 2 years). 35 patients had cerebral palsy, 5 patients were syndromic, and 1 patient had myelomeningocele. The average preoperative weight was 35 kg and all were wheelchair ambulators. Total traction applied on average was 49% of the preoperative body weight. Mean preoperative coronal deformity was 91° which improved to 43° at final follow-up (53% correction). Push-supine imaging had the strongest correlation to major coronal deformity outcome at final follow-up (r2 = 0.87, p ≤ 0.0001). Compared to push-supine imaging, there was a mean greater coronal deformity correction of 18 ± 10° (p ≤ 0.0001) at final follow-up. To predict the final coronal deformity, the regression equation was final Cobb angle = 1.13085 + preop push-supine Cobb angle × 0.68830. Mean preoperative pelvic obliquity was 34° which improved to 12° at final follow-up (65% correction). Push-supine imaging had the strongest correlation to pelvic obliquity outcome at final follow-up (r2 = 0.59, p = 0.0001). Compared to push-supine imaging, there was a mean greater pelvic obliquity correction of 3 ± 10° (p = 0.0857) at final follow-up. The regression equation was final POB = 6.42096 + preop push-supine POB × 0.36675. Mean preoperative kyphosis was 70° and 52° at final follow-up (26% correction). CONCLUSION The results of this study demonstrated for preoperative planning that the push-supine flexibility radiograph is most predictive of the coronal deformity and of the pelvic obliquity correction. At final follow-up in this NMS population, there was a mean greater improvement of 18° for coronal deformity versus preoperative push-supine imaging and 3° for pelvic obliquity versus preoperative push-supine imaging. At the time of PSF, ITx is an effective adjunct technique to improve coronal deformity and POB for NMS producing 53% coronal correction, 65% POB correction, and 26% kyphosis correction. LEVEL OF EVIDENCE IV.