Anterior release may not be necessary for idiopathic scoliosis with a large curve of more than 75° and a flexibility of less than 25.

BACKGROUND CONTEXT

To improve correction and fusion rates, an anterior release is often needed for the treatment of idiopathic scoliosis with a curve of more than 75° before posterior correction, instrumentation, and fusion. However, there are disadvantages to anterior release, and we are concerned about whether it is necessary for anterior-posterior spinal fusion in these patients.

PURPOSE

The objective of this study was to compare the surgical results for idiopathic scoliosis with a curve of more than 75° and a flexibility of less than 25% between using posterior-only approach and combined anterior release followed by posterior correction with a hybrid construct (hooks and pedicle screws) and spinal fusion.

STUDY DESIGN/SETTING: This was a retrospective cohort study.

PATIENT SAMPLE

From 2000 to 2014, 388 consecutive patients with idiopathic scoliosis were treated surgically at our hospital. Of these patients, 53 whose primary curves were more than 75° with a flexibility of less than 25%, at an incidence of 13.6%, were included and divided into two groups. Thirty-one patients (mean age: 16.3 years old) who underwent anterior release followed by posterior correction, instrumentation, and fusion were included in the A+P group, and the remaining 22 patients (mean age: 17.3 years old) were designated as the P group for posterior procedure alone.

OUTCOME MEASURES

The clinical outcomes were analyzed in terms of correction and loss of correction and by the Scoliosis Patient Questionnaire: Version 30 functional questionnaire.

MATERIALS AND METHODS

In the A+P group, halo-femoral traction was applied for 1 week between the anterior release and the posterior procedure. Posterior instrumentation with a hybrid construct with hooks and pedicle screws was used for both groups. The radiological and functional outcomes were compared between the two groups.

RESULTS

The average preoperative Cobb angle was 85.3° for the A+P group, with an average 17.4% flexibility, and 80° for the P group, with 15.3% flexibility. The postoperative Cobb angle was 53.1° for the A+P group and 45.6° for the P group. The Cobb angle at the final follow-up for the A+P group was 55.2° and that for the P group was 48°. The average correction rates of the A+P and P groups were 37% and 43.4%, respectively. There were no statistically significant differences between the groups in gender, age, number of levels fused, and flexibility of coronal curve. With a minimum 2-year follow-up, similar results were found between these two groups in terms of correction rate, loss of correction, and functional outcome.

CONCLUSIONS

In this study, we found that a posterior-only approach with hybrid construct (hooks and pedicle screws) could provide a correction similar to that of an anterior-posterior approach. Also, the disadvantages of anterior release could be avoided by the posterior-only approach.