Role and technique of eggshell osteotomies and vertebral column resections in the treatment of fixed sagittal imbalance.

Fixed sagittal imbalance of the spine leads to a disabling posture with compensatory hip and knee flexion. The most common causes of fixed sagittal imbalance include degenerative lumbar disease, complications from the use of distraction instrumentation in the lower lumbar spine, ankylosing spondylitis, and posttraumatic kyphosis. Surgical procedures to correct sagittal deformities include the posterior Smith-Petersen osteotomy, pedicle subtraction osteotomy, and posterior vertebral column resection. For complex multiplanar deformities, combined anterior and posterior vertebral column resection may be needed to provide vertebral column shortening and balanced correction in the coronal and sagittal planes. Current reports of these procedures stress the importance of patient selection, radiographic evaluation, and meticulous surgical technique. Complications include excessive blood loss, incomplete correction, wound infection, and pseudarthrosis. Most patients who are treated with these procedures report a high level of satisfaction with the outcome.