[Anterior endoscopic release/posterior spinal instrumentation for severe and rigid thoracic adolescent idiopathic scoliosis].

OBJECTIVES: To compare the results of spinal correction for severe and rigid thoracic adolescent idiopathic scoliosis (T-AIS) by combined anterior endoscopic release/posterior hybrid constructs of proximal hooks and distal pedicle screws spinal fusion (APSF) and an all-pedicle screw construct posterior-only spinal fusion (PSSF).

METHODS: T-AIS patients with curves ≥ 70° and flexibility ≤ 50% who underwent APSF from November 2001 to December 2008 were retrospectively reviewed (APSF group). In addition, the patients treated by PSSF with comparable curve severity and flexibility were selected as control (PSSF group). All patients had a minimum 2-year follow-up. The thoracic curve and kyphosis were measured on standing long-cassette posteroanterior and lateral radiographs of entire spine taken at pre-operation, post-operation and last follow-up. The radiographic parameters, fusion levels, implant density and complications were compared between two groups.

RESULTS: There were 18 patients treated with APSF and 27 with PSSF, with mean age of (15.9 ± 2.1) years and (15.8 ± 2.9) years, respectively. In patients treated with APSF, the mean thoracic curve was 87° ± 12° with 58% ± 13% correction after operation; while in those treated with PSSF, the mean thoracic curve was 79° ± 8° with 59% ± 8% correction after operation. The number of levels fused was 12.7 ± 1.2 and 12.8 ± 1.4, while the implant density was 48% ± 5% and 61% ± 6% in APSF group and PSSF group, respectively. Patients treated with APSF and PSSF were followed by (4.5 ± 0.6) years and (2.8 ± 0.7) years, with a mean loss of correction of 4.4° and 1.9° at final follow-up. Despite the significant higher implant density found in PSSF (t = 6.123, P < 0.001), there were no statistically significant differences between the groups for gender, age, number of levels fused, preoperative coronal/sagittal Cobb measurements, coronal curve flexibility, or amount of postoperative coronal Cobb correction.

CONCLUSIONS: In patients with severe and rigid T-AIS, PSSF could achieve same curve correction as an APSF by increasing implant density. In treating scoliosis patients with high risk of having loss of curve correction, implant complications or pseudarthrosis, APSF is recommended to achieve solid spinal fusion.