Posterior lumbar osteotomy for flat back in adults.

Several studies describe sagittal realignment for flat back and related kyphotic decompensation. Official guidelines for sagittal and the frontal realignment have not been developed. In this retrospective study, the authors examined 10 patients with flat back syndrome and treated a related kyphotic decompensation syndrome by posterior wedge osteotomy. The authors' goal was to determine the efficacy of one-level osteotomy on sagittal and frontal realignment. The effectiveness of osteotomy performed mainly in L3 or L4 was measured in terms of radiographic sagittal and frontal alignment. Sagittal unbalance was improved in all patients. The correction is related to the restitution of lumbar lordosis (5 degrees of lordosis allows 1 cm of sagittal correction). However, frontal balance is difficult to restore or even to maintain. In one patient, it was worsened and required repeated operation. One-level lumbar osteotomy is a safe procedure to correct sagittal unbalance. Peroperative lordosis correction allows reliable correction planning. The remaining problem is planning for frontal balance correction.