Posterior 3-Column Osteotomy for Treatment of Congenital Kyphosis with Multiple Thoracolumbar/Lumbar Anterior Unsegmented Vertebrae: A Comparison Between Patients with Increasing Number of Anterior Unsegmented Vertebrae.

Abstract

A 3-column osteotomy is sometimes challenging in congenital kyphosis (CK) with many anterior unsegmented vertebrae (AUVs). This study compared surgical outcomes of single-level 3-column osteotomy and associated complications in CK with increasing number of AUVs. We retrospectively reviewed 25 consecutive patients with AUVs in CK who underwent surgery at a mean age of 16.2 ± 10.3 years. Patients were stratified into 2 groups according to the number of AUVs: 3 AUVs and ≥4 AUVs. Osteotomy types, surgical outcomes, and related complications were analyzed and compared between groups. The 3 AUVs group comprised 13 patients, and the ≥4 AUVs group comprised 12 patients. Pedicle subtraction osteotomy, grade 4 osteotomy, vertebral column resection, and vertebral column decancellation accounted for 15.4%, 38.5%, 46.1%, and 0% of procedures in the 3 AUVs group and 8.3%, 0%, 83.3%, and 8.3% of procedures in the ≥4 AUVs group. Preoperative focal kyphosis, which was significantly higher in the ≥4 AUVs group (82.9° ± 28° vs. 59.7° ± 9.4°, P = 0.010), was corrected in both groups postoperatively. The ≥4 AUVs group had significantly higher remaining kyphosis (33.6° ± 13.4° vs. 15.1° ± 9.1°, P < 0.001) with a significantly lower correction rate (61.2% ± 13.6% vs. 75.0% ± 15.6%, P = 0.001). The complication rate, mainly involving vertebral subluxation and proximal junctional kyphosis, was significantly higher in the ≥4 AUVs group than the 3 AUVs group (8/12 vs. 1/13, P = 0.004). Posterior single-level 3-column osteotomy can achieve satisfactory kyphosis correction in CK with 3 AUVs. Decreasing kyphosis correction and increasing surgery-related complications are prone to develop when treating CK with ≥4 AUVs.