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

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.