Mid-term results of computer-assisted skip pedicle screw fixation for patients with Lenke type 1 and 2 adolescent idiopathic scoliosis: A minimum five-year follow-up study.

PURPOSE: In skip pedicle screw fixation for adolescent idiopathic scoliosis (AIS), the mid-term effects of reducing screw number on correction and clinical results are uncertain. We clarified the mid-term outcomes of this technique in patients with Lenke type 1 and 2 AIS.

METHODS: Thirty-four patients who underwent skip pedicle screw fixation (mean screw density: 1.35 screws) for Lenke type 1 and 2 AIS were retrospectively reviewed. The follow-up period was at least 5 years (mean follow-up period: 6.1 years), and the follow-up rate was 89.5%. Radiological parameters and clinical symptoms were evaluated before, immediately after, and at 2 years and 5 years after surgery.

RESULTS: The mean Cobb angle of the main thoracic (MT) curve before, immediately after, at 2 years after surgery, and at the final 5-year minimum follow-up was 52.5°, 16.4°, 20.5°, and 19.4°, respectively. The Cobb angle of the MT curve was significantly improved immediately after, at 2 years after surgery, and at the final follow-up compared with that before surgery (p < 0.01). The mean correction rate immediately after surgery was 69.0% and the rate of correction loss at the final follow-up was 8.3%. All Scoliosis Research Society-22 patient questionnaire (SRS-22r) sub scores 5 years after surgery were significantly improved compared with those beforehand (p < 0.01).

CONCLUSIONS: Correction using skip pedicle screw fixation in AIS was well maintained from the initial follow-up measurements to the final follow-up. The SRS-22r sub scores at the final follow-up were significantly improved over preoperative levels.