Prospective Pulmonary Function Comparison of Open vs Endoscopic Anterior Fusion Combined with Posterior Fusion in Adolescent Idiopathic Scoliosis

Introduction: Open or endoscopic approaches to the thoracic spine in combination with posterior instrumentation and fusion is often indicated for large and stiff curves, hyperkyphosis, and those patients at risk of crankshaft. To our knowledge there has never been a comparison between a formal open thoracotomy and endoscopic release and fusion for the circumferential operative treatment of AIS curves.

Purpose: To prospectively compare the pulmonary function of AIS patients undergoing circumferential spinal fusion with either an open or endoscopic anterior approach at a minimum 2-year F/U.

Methods: 11 patients undergoing a VAT release/fusion (VAT group) followed by posterior instrumentation and fusion (PSF-I) were compared to 11 patients undergoing an open thoracotomy (Open group) followed by a PSF-I. All patients had operative AIS, and were treated circumferentially for either large curve size (Cobb >80º), hyperkyphosis (T5-T12 Cobb > 70º), or crankshaft prevention (Risser 0, tri-radiate cartilage TRC-Open). The average age of patients in the VAT group was 13+2 (range 10-16), and the open group 12+10 (range 10-15). The average preoperative thoracic Cobb was 75º in the VAT group and 76º in the open group. All patients had autogenous rib graft for their anterior fusion and iliac crest graft for their posterior fusion. All patients had PFTs consisting of Forced Vital Capacity (FVC) and Forced Expiratory Volume in one second (FEV-1) preop and a minimum 2 years postop.

Results: (see table) Both groups had PFT parameters that were improved postop vs preop, but not statistically significant (p>.05).

Discussion: The use of endoscopic release and fusion for the circumferential treatment of operative AIS has improved PFTs for both FVC and FEV-1 at 2 years postop similar to the open group, although neither group has statistically improved values.

Conclusions: Endoscopic VAT release/fusion in association with a posterior instrumentation and fusion for select AIS curves requiring this circumferential treatment demonstrates improved PFTs 2 years postop similar to those of a formal open thoracotomy but not statistically. These results confirm the use of either an open or a VAT approach when appropriate in this patient population to maximize pulmonary function postoperatively.

Results: