Loss of Sagittal Balance and Clinical Outcomes following Corrective Osteotomy for Lumbar Degenerative Kyphosis

Abstract

Purpose: To report the loss of correction of a sagittal imbalance and the clinical outcomes after a corrective osteotomy for lumbar degenerative kyphosis. Materials and Methods: This study analyzed the radiological parameters, surgical techniques, and clinical outcomes of 23 patients, who underwent corrective osteotomy for lumbar degenerative kyphosis. The patients were divided into groups I (＞5 cm loss of correction of sagittal imblance, 12 patients) and II (＜5 cm, 11 patients) to compare the patients with the correction preserved with those with the correction lost. In terms of the clinical outcome, group A (high satisfaction score group ＞3.5 out of 5, 11 patients) was compared with group B (low satisfaction score group＜3.5 out of 5, 12 patients). Results: The sagittal imbalance was corrected by performing a Smith-Petersen osteotomy (SPO) in 11 cases and Pedicle subtraction osteotomy (PSO) in 12. The mean preoperative sagittal imbalance was improved from 26.4 cm to 4.05 cm, postoperatively, and 11.2 cm at the last follow up. The mean loss of correction was 11.2 cm in group I and 2.3 cm in group II. The mean satisfaction score was 4.56 in group A and 2.18 in group B. The presence of an old compression fracture was found to be related to the loss of correction, and the preoperative symptomatic spinal stenosis was related to poor clinical outcomes. Conclusion: After mean 45 month follow up, the mean loss of sagittal correction was 38.3%, which mainly occurred at the proximal unfused segment. The clinical success rate was 45.5%, regardless of the loss of sagittal balance correction.