Corrective osteotomies in spine surgery.

Spinal deformities can result in increasing thoracic kyphosis or loss of lumbar lordosis, leading to imbalance in the sagittal plane. Such deformities can be functionally and psychologically debilitating. The Smith-Petersen osteotomy can achieve approximately 10 degrees of correction in the sagittal plane at each spinal level at which it is performed. This osteotomy is beneficial for patients who have a degenerative imbalance in the sagittal plane. The pedicle subtraction osteotomy can achieve approximately 30 degrees to 40 degrees of correction in the sagittal plane at each spinal level at which it is performed. It is the preferred osteotomy for patients with ankylosing spondylitis who have an imbalance of the spine in the sagittal plane. The cervical extension osteotomy is performed in the cervical spine, at the cervicothoracic junction, in patients who have a cervical flexion deformity that impedes their ability to look straight ahead while walking or who have difficulty swallowing. The vertebral column resection is used when the imbalance is severe enough that the other osteotomies cannot correct the deformity, especially in patients who have a combined sagittal and coronal spinal imbalance. Neurologic problems, whether transient or permanent, are the most commonly encountered complications following these procedures. Recent results have shown a high patient satisfaction rate and good functional outcomes after spinal osteotomies done to treat a variety of disorders.