Comparison of 2 Surgeries in Correction of Severe Kyphotic Deformity Caused by Ankylosing Spondylitis: Vertebral Column Decancellation and Pedicle Subtraction Osteotomy

Abstract

To compare the treatment results between 1-level vertebral column decancellation (VCD) and pedicle subtraction osteotomy (PSO) for correcting severe kyphotic deformity in ankylosing spondylitis (AS). VCD and PSO have been used to correct AS-related kyphotic deformity, but the differences on correcting results between VCD and PSO are not clear. Between 2013 and 2015, 57 patients underwent 1-level spinal osteotomy (VCD: n= 30; PSO: n= 27) for correcting kyphotic deformity. Sagittal parameters, fusion results, surgical information, and clinical outcomes were documented and compared. All data were obtained before and 1 week after surgery, 6 months after surgery, and at final follow-up (at least 2 years). VCD provided significantly greater osteotomy angle (50.8° ± 9.7°) than PSO (38.5° ± 6.1°). In the VCD group, the change of the anterior column was 5.0 ± 1.3 mm, which was larger than the PSO group. The middle column was shortened by 9.9 ± 2.0 mm and 19.1 ± 3.3 mm in the VCD group and PSO group, respectively. There was no significant difference in operating time and blood loss between the 2 groups. All cases had solid fusion. Between the 2 groups, Scoliosis Research Society Outcomes Instrument-22 scores were similar at the final follow-up. No major acute complications occurred in both groups. VCD is a safe and effective method in treating rigid kyphotic deformity secondary to AS. VCD provides a larger correction angle in one segment and preserves more height of osteotomized vertebrae than PSO.