L5 pedicle subtraction osteotomy: indication, surgical technique and specificities.

Abstract

To evaluate the radiographic, functional outcomes, complications and surgical specificities of L5 pedicle subtraction osteotomy for fixed sagittal and coronal malalignment. A retrospective cohort of consecutive patients with prospectively collected data. Ten patients who underwent PSO at L5 were eligible for a 2-year minimum follow-up (average, 4.0years). Patients were evaluated by standardized upright radiographs. Preoperative and postoperative radiographies, surgical data and complications were collected. All surgeries were revision surgeries. The mean lumbar lordosis before surgery was -22.5° (range, 8° to -33°) and improved to -58.5° (range, -40° to -79°). The sagittal vertical axis demonstrated a preoperative mean sagittal malalignment of 13.7cm (range 3.5 to 20cm), with correction to 4.6cm postoperatively. Three patients required additional surgery at the latest follow-up for rod breakage. PSO of L5 can be a safe and effective technique to treat and correct fixed sagittal imbalance and provide biomechanical stability. The high complication rate mandates a careful assessment of the risk/benefit ratio of such a major surgery. Most patients are satisfied, particularly when sagittal balance is achieved.