Both OWO and CWO were safe and enabled substantial correction, with good clinical results. CWO resulted in a significantly longer operative time and more bleeding but offered fewer instances of paralytic ileus or delayed union with a broken rod.

Posterior correction and fixation is effective for treating pseudarthrosis with kyphosis in ankylosing spondylitis. No anterior fusion procedure was necessary.

COWO is a useful procedure for patients with sagittal imbalance requiring more than 35 degrees lordotic correction through the osteotomy site. A worse clinical result is associated with increasing patient comorbidities, pseudarthrosis in lumbosacral fusion, and junctional kyphosis.