Posterior spinal fusion versus anterior/posterior spinal fusion for adolescent idiopathic scoliosis: a decision analysis.

STUDY DESIGN

Decision analysis.

OBJECTIVE

To determine the optimum surgical strategy for skeletally immature females with large idiopathic spinal curves.

SUMMARY OF BACKGROUND DATA

Curve progression after posterior instrumentation is a concern for skeletally immature patients with large scoliotic curves. Anterior/posterior spinal fusion is preferred by some surgeons to treat this specific population. Combined fusions carry higher inherent risk of pulmonary and neurologic complication. Large data sets of complication rates have only recently become available. To date no direct comparison between the 2 approaches has been made using the most recent data.

METHODS

A model was constructed to compare the effectiveness of the 2 surgical approaches. Rates of complications and revisions were acquired from the surgical literature. Utilities were obtained from earlier studies and conversion of SF-36 data for the health states included the model. Effectiveness was measured by quality-adjusted life years. Sensitivity analysis was used to test the robustness of the model and identify variables that impact the clinical decision.

RESULTS

The results of our model showed anterior/posterior spinal fusion to be the preferred surgical approach for treating scoliosis in skeletally immature females. Anterior/posterior spinal fusion resulted in a net gain of 6.17 quality-adjusted life years. Variables that impacted the results of the model were the probability of curve progression for the 2 surgical approaches and the surgical mortality of anterior/posterior spinal fusion. Curve progression rates vary considerably in the literature and are based on small samples and dated surgical techniques.

CONCLUSION

Our model favors anterior/posterior spinal fusion for surgical correction of large thoracic curves in skeletally immature females. The probability of curve progression after spinal fusion is the main variable that dictates the optimal surgical approach and rates in the literature are based on outdated surgical instrumentation. Future observational studies are warranted to acquire more accurate curve progression rates.