Long-term Surgical Outcomes After Early Definitive Spinal Fusion for Early-onset Scoliosis With Neurofibromatosis Type 1 at Mean Follow-up of 14 Years.

BACKGROUND: Several authors mentioned surgical outcome for scoliosis associated with neurofibromatosis type 1 (NF-1). However, no studies have summarized long-term surgical outcomes after surgical treatment of early-onset scoliosis (EOS) with NF-1. The purpose of this study is to evaluate the long-term surgical outcome after early definitive spinal fusion for EOS in NF-1 patients.

METHODS: We performed a retrospective review on a cohort of 11 patients diagnosed with EOS associated with NF-1 between 1990 and 2009 in our hospital. The study included 7 male and 4 female NF-1 patients with a mean age at fusion surgery of 8 years 4 months who underwent early definitive spinal fusion for EOS. We reviewed radiographs, computed tomography and magnetic resonance images for each patient. The data collected included type of NF-1, Cobb angles, kyphotic angle, spinal length (T1-S1), and pulmonary function. We also evaluated progression of the dystrophic change through radiographs and computed tomography during the follow-up period.

RESULTS: The mean follow-up duration was 14 years (5 y 10 mo to 25 y). All patients underwent anterior and posterior fusion surgeries in either 1 or 2 stages. Seven cases had subtotal tumor resection from the concave side followed by rib strut grafting. The mean preoperative Cobb angle of the primary curve was corrected from 71.2 to 24.1 degrees and was maintained at the final follow-up at 23.5 degrees. Mean values for preoperative and final follow-up T1-S1 heights were 30.7 and 36.2 cm, respectively. Mean values for preoperative and final follow-up % forced vital capacity (the present/the predicted) were 75.0% and 74.4%, respectively. The dystrophic change progressed in all cases during the long-term follow-up.

CONCLUSIONS: Our goals for NF-1 scoliosis are to obtain deformity correction, to achieve stable instrumentation by using longer fusion levels and to attain a solid fusion mass that can tolerate continual erosion during the long-term follow-up. We achieve this by using a circumferential approach for EOS associated with NF-1.

LEVEL OF EVIDENCE: Level IV-case series.