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

Abstract

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.

Keywords: Anterior release; Hybrid instrumentation; Idiopathic scoliosis; Large and stiff curve; Posterior spinal fusion; Surgical outcomes.