Asymmetric osteotomy of the spine for coronal imbalance: a technical report.

STUDY
DESIGN: Technical report on the surgical technique of asymmetric osteotomy of the spine for coronal imbalance.
OBJECTIVE: To describe a successful method of performing asymmetrical pedicle subtraction osteotomy (APSO) through a posterior only approach. SUMMARY OF
BACKGROUND: Rigid coronal deformity of the spine can be sharply angulated and can create significant coronal imbalance. Surgical correction is the only definitive treatment of restoring the balance as bracing is unhelpful. Corrective surgery can be anterior or posterior. The literature on the methods of surgical correction of rigid coronal deformities of the spine is limited. Unlike osteotomies for sagittal imbalance, blunt dissection of the anterior cortex is necessary in asymmetrical osteotomy to allow resection of the anterior cortex for closure of the wedge. We describe a method by which we performed this in the thoracic and lumbar spine with case examples.
METHOD: After insertion of pedicle screws, laminectomy and unilateral facetectomy of the proposed level of osteotomy is performed. Next, dissection lateral to the pedicle and vertebral body is performed bluntly with mastoids to reach the front of the anterior cortex and confirmed with fluoroscopy. An oblique osteotomy including the lateral and posterior cortex is performed above and below the pedicle under imaging. The osteotomy site is closed through unilateral compression.
CONCLUSION: Satisfactory correction of coronal deformity can be achieved with APSO from an isolated posterior approach. In contrast to sagittal osteotomies, blunt dissection along the anterior cortex is necessary to allow safe resection of anterior cortical bone for closure of the wedge.