Management of Fixed Sagittal Plane Deformity: Outcome of Combined Anterior and Posterior Surgery

Study Design. Retrospective study of consecutive patient series. Objectives. To review the radiographic and clinical results of patients with preoperative fixed sagittal imbalance treated with combined anterior and posterior arthrodesis, and to determine factors that predict clinical outcome. Summary of Background Data. Combined anterior and posterior arthrodesis of the spine is useful in the management of fixed deformity involving the coronal and sagittal planes. The specific indications for combined surgery in the patient with regional and global imbalance have not been well defined. Methods. Retrospective review of 25 consecutive patients treated with combined anterior and posterior spinal arthrodesis. Inclusion criteria included a preoperative global sagittal imbalance of at least 5 cm. Outcome variables included radiographic measures of preoperative, postoperative, and follow-up films, and a clinical assessment using the Modified SRS Outcomes Instrument and a review of postoperative complications. Results. Twenty-five consecutive cases were reviewed. Mean age was 58 years (range 38–77), and mean follow-up was 55 months (range 24–81) for clinical and 44.5 (range 24–81) months for radiographic outcome variables. The mean preoperative sagittal imbalance was 10.5 cm (range 5.2–23.3), which improved to 2.9 cm (range 0–12.6) after surgery, and was maintained as 3.3 cm (range 0–13.5) at follow-up. Mean lumbar lordosis was −23° (range +40 to −47) before surgery, and increased to −42° at follow-up (range −20° to −60°), an increase of 19°. Patients with preoperative regional hypolordosis in the lumbar spine that was corrected surgically had the highest postoperative scores. The mean score for patient satisfaction with surgical management was 4.45 (range 2.5–5). Correlation analysis of clinical outcome domains demonstrated that patient satisfaction correlated poorly with domains of pain (r = 0.37, P = 0.1) and function (r = 0.4, P = 0.09). Within the domains, self-image showed highest correlation with patient satisfaction (r = 0.65, P = 0.006) and total score (r = 0.89, P = 0.0001). Conclusions. Patients with global sagittal imbalance of the spine were effectively treated with a combined anterior and posterior arthrodesis as measured by radiographic parameters. Patient satisfaction with surgery, and overall clinical outcomes were best in cases that resulted in an increase in lumbar lordosis. The subset of patients with preoperative regional hypolordosis of the lumbar spine has better outcomes than those with preoperative lumbar lordosis in the physiologic range.