Outcomes of Posterior Lumbar Hemivertebra Resection and Short Fusion in Patients With Severe Sacral Tilt

OBJECTIVE: To introduce surgical strategies to restore coronal balance during limited fusion for early lumbar hemivertebra resection in patients with severe sacral tilt. METHODS: Sacral tilt was defined as a sacral tilt angle ≥ 5, and severe sacral tilt was defined as a sacral tilt angle > 10. From July 2004 to December 2017, 73 consecutive patients treated with posterior hemivertebra resection and short fusion in our institution were evaluated. Severe sacral tilt was noted in 26 patients (14 boys and 12 girls), and all were enrolled in this study. Undercorrection of the primary lumbar curve as compensation for the sacral tilt and short fusion was performed in these patients. The medical charts and imaging data of the patients were retrospectively reviewed to evaluate the outcomes. RESULTS: All patients were followed for at least 2 years. The mean age at the time of surgery was 3.7 (2–9) years old, with a total of 31 lumbar hemivertebra excised. On average, 2.8 (2–5) segments were fused for each patient. Sacral tilt minimally improved from 14.5° preoperatively to 13.6° postoperatively (p=0.15) and remained stable at the follow-up. The overall lumbar curve was 41.9° preoperatively, 11.7° immediately postoperatively, and 14.6° at the final follow-up. The segmental scoliosis curve was 39.1° preoperatively, 9.7° immediately postoperatively, and 11.2° at the final follow-up. Segmental kyphosis was corrected from 27.2° to 6.5° after the surgery and was 7.1° at the latest follow-up. CONCLUSION: Sacral tilt is seen in patients with congenital scoliosis in lumbar hemivertebra. Undercorrection of the lumbar curve and segmental scoliosis to compensate for sacral tilt and short fusion after hemivertebra resection may be helpful to restore coronal balance and preserve mobility in segments in patients with pronounced severe sacral tilt.