The treatment of large (>70 degrees) thoracic idiopathic scoliosis curves with posterior instrumentation and arthrodesis: when is anterior release indicated?

STUDY DESIGN

Retrospective clinical study from 2 centers.

OBJECTIVE

To analyze the efficacy of posterior instrumentation and arthrodesis for thoracic idiopathic scoliosis curves more than 70 degrees.

SUMMARY OF BACKGROUND INFORMATION

The increasing use of thoracoscopic techniques in deformity surgery has led several investigators to advocate anterior release followed by posterior instrumentation when treating "stiff" thoracic curves 60 degrees-70 degrees. To our knowledge, no study has been published to define indications for anterior surgery in thoracic idiopathic scoliosis.

METHODS

This is a retrospective review of patients 20 years and younger, with idiopathic scoliosis and thoracic curves more than 70 degrees treated with isolated posterior instrumentation and arthrodesis at 2 institutions from 1989 to 1999. A total of 50 patients were identified, and 46 were available for minimum 2-year radiographic follow-up. Of the 50 patients, 44 had bend films taken before surgery. All patients were treated with third-generation segmental spinal instrumentation using a varied combination of hooks, wires, and screws.

RESULTS

Average patient age at surgery was 14.4 years (range 10-20), and average radiographic follow-up was 4.4 years (range 2-11.5). Average preoperative thoracic curve was 75 degrees (range 70 degrees-88 degrees), and average bend was 47 degrees (range 28 degrees-60 degrees), a flexibility of 37%. Average postoperative curve was 25 degrees (range 10 degrees-46 degrees), and it was 27 degrees (range 11 degrees-46 degrees) at latest follow-up, a correction of 64%. The average length of surgery was 6.15 hours, mean hospital stay was 8 days, and average blood loss was 1100 cc. The Scoliosis Research Society 22 or 24 was available at a minimum of 2 years in 46 of 50 patients. Mean domain scores were: pain 4.4, self-image 4.3, function 4.3, mental health 4.3, satisfaction 4.7, and total 4.4. Complications included 1 pseudarthrosis, 1 implant removal for prominence, and 1 implant removal for late operative site pain.

CONCLUSION

Using posterior surgery only, we have been able to at least equal the results reported in the literature by investigators using combined approaches. Isolated posterior instrumentation and arthrodesis achieve satisfactory cosmetic, radiographic, and patient-based outcomes in adolescents with idiopathic scoliosis with thoracic curves 70 degrees-90 degrees, without the added expense and morbidity of anterior release.