Survivorship analysis after primary fusion for adult scoliosis. Prognostic factors for reoperation

Abstract

Background context: Adult scoliosis surgery is a challenging procedure with high rate of complications and reoperations. Reoperation rates vary widely. Long-term survival for this surgery still remains unknown, and the prognostic factors for reoperation are not well defined.

Purpose: To assess adult scoliosis surgery survival (without the need of reoperation) after primary fusion in adults with mainly frontal deformity and to define prognostic factors for reoperation.

Study design: Survival analysis of a cohort of consecutive adult patients, primarily operated on scoliosis using segmental instrumentation (retrospective cohort study).

Patient sample: Fifty-nine patients older than 21 years at primary surgery (median age, 42 years), who presented idiopathic or degenerative curves with frontal Cobb >40° (median preoperative frontal Cobb 59°), more than four-level fusion, and a 2-year minimum postoperative follow-up (median, 8.5 years; 41% patients had a longer than 10-year follow-up).

Outcome measures: Clinical and preoperative radiographic parameters were analyzed preoperatively and evaluated as prognostic factors for reoperation.

Methods: Survival was estimated using Kaplan-Meier method. Prognostic factors (clinical and radiographic) for reoperation were evaluated. Logistic regression using backward elimination was used for multivariate analysis.

Results: Survival was 89.8% at 1 year, 79.4% at 2 years, 73.4% at 3 years, 64% at 5 years, and 60.9% at 10 years. Overall, 21 patients (35.6%) underwent revision surgery. The most common reasons for reoperation were painful/prominent implants, adjacent-segment degeneration, and infection. American Society of Anesthesiologists Type II patients and double surgical approach were associated with a higher revision rate. Preoperative thoracic kyphosis was significantly higher in reoperated patients.

Conclusions: The 10-year survival rate of primary scoliosis surgery in adult patients is 61%. Risk factors identified for reoperation included patients with higher morbidity, double surgical approach, and preoperative thoracic hyperkyphosis.

Keywords: Adult scoliosis; Prognostic factors; Reoperation; Survival.