Anterior screw-plate fixation in adolescent idiopathic scoliosis: 15-year outcomes

Background: Few published data are available on long-term outcomes of anterior spinal fusion for adolescent idiopathic scoliosis (AIS). The objective of this single-centre retrospective study was to assess clinical and radiological outcomes of one-stage anterior spinal fusion achieved using precontoured titanium anterior screw-plates.

Hypothesis: Our hypothesis was that anterior instrumentation produced both good functional outcomes and good correction in the coronal and sagittal planes.

Material and methods: This procedure was performed in 111 patients between 1975 and 1993. Among them, those who underwent a comprehensive evaluation at least 15 years later were included. The SRS-30 questionnaire and Oswestry Disability Index (ODI) were used to assess functional outcomes. Radiographic outcomes were evaluated on antero-posterior and lateral full-spine radiographs obtained pre-operatively, post-operatively, and at last follow-up.

Results: The study included 35 patients, who were re-evaluated after a mean of 21 years (15-31 years). Mean pre-operative Cobb's angle was 44°, mean age at surgery was 14.7 years, mean SRS-30 score was 3.65/5, and mean ODI was 14.9%. At last follow-up, mean Cobb's angle was 14.7° and 25 patients exhibited coronal misalignment with a mean deviation of 12mm. In the sagittal plane, the mean sagittal vertical axis (SVA) measured using the C7 plumb line was -28mm, with 8mm of anterior translation compared to the post-operative value (36mm). The functional outcome assessed using the SRS-30 score correlated significantly with pelvic tilt and anterior SVA translation.

Conclusion: Anterior spinal fusion produces good long-term functional outcomes in AIS. Correction is both satisfactory and sustained. Anterior SVA translation over time may be associated with better functional outcomes.

Level of evidence: IV (retrospective study).