Surgical Treatment of Scoliosis-Associated with Syringomyelia: The Role of Syrinx Size

Background: The treatment of the syrinx prior to correction of the scoliosis in syringomyelia-associated scoliosis (SMS) patients remains controversial. The aim of this study is to evaluate the role of the syrinx size in the management of SMS patients. Materials and Methods: This was a retrospective study of 36 SMS patients. They were divided into 2 groups: Group A (26 with a small syrinx, syrinx(S)/spinal cord(C) ratio ≤0.7) and Group B (10 with a large syrinx, S/C ratio >0.7). Patients with a large syrinx accepted prophylactic neurosurgery prior to scoliosis surgery. They were evaluated at baseline, 1-week and last follow-up after correction surgery for changes in curve correction, global coronal balance, thoracic kyphosis (TK), sagittal vertical axis (SVA), and Scoliosis Research Society (SRS)-22 scores. Results: The syrinx size of patients in Group A was significantly smaller than that of in Group B. The syrinx size was significantly decreased after prophylactic neurosurgery in Group B. The radiographic parameters of scoliosis at baseline, 1-week and last follow-up after scoliosis surgery were comparable between two groups. No abnormal signal was detected during the process of neuromonitoring in both groups. Pre- and postoperative SRS-22 scores were similar between two groups. Conclusions: Prophylactic neurosurgery may be beneficial for decreasing the risk of correction surgery in SMS patients with large syrinx (S/C ratio >0.7). After the intervention of syrinx prior to scoliosis correction, SMS patients with large syrinx could obtain similar clinical and radiographic outcomes of treatment with pedicle-screw-based spinal instrumentation and fusion compared to the patients with small syrinx.