The Sagittal Parameters and Efficacy of Pedicle Subtraction Osteotomy in Patients with Ankylosing Spondylitis and Kyphosis Under Different Lumbar Sagittal Morphologies

Abstract

Objective This study aimed to compare the changes in sagittal parameters and the efficacy of pedicle subtraction osteotomy (PSO) in patients with ankylosing spondylitis (AS) and kyphosis under different lumbar sagittal morphologies and to explore the effect of sagittal morphology on the selection of PSO levels. Methods A total of 24 patients with AS and thoracolumbar kyphosis (TK) who were admitted to the First Affiliated Hospital of Xinjiang Medical University between 2008 and 2019 were enrolled in this study. They were divided into two groups: a lumbar lordosis group (n = 14) and a lumbar kyphosis group (n = 10). Changes in sagittal parameters, lumbar Japanese Orthopaedic Association (JOA) scores, and visual analog scale (VAS) scores for lumbar pain before and after operation were compared between the two groups to evaluate postoperative efficacy. Results The preoperative lumbar lordosis (LL) was −29.29 ± 5.40 (lordosis) and 13.50 ± 3.65 (kyphosis) ( P < 0.01), and the preoperative sagittal vertical axis (SVA) was 171.35 ± 25.46 (lordosis) and 223.58 ± 21.87 (kyphosis) ( P < 0.01). Preoperative global kyphosis (GK) was 75.71 ± 5.26 (lordosis) and 86.30 ± 10.32 (kyphosis) ( P < 0.05). All patients in the lordosis group underwent PSO surgery at the twelfth thoracic vertebra (T12) or the first lumbar spinal vertebra (L1), while all patients in the kyphosis group underwent the surgery at the second or third lumbar spinal vertebra (L2 or L3). The differences in postoperative GK, LL, and SVA between the two groups were not significant ( P > 0.05). The JOA scores of the two groups increased from 13.00 ± 0.83 (lordosis) and 11.30 ± 0.93 (kyphosis) before surgery to 21.00 ± 0.67 and 19.70 ± 0.60 after surgery ( P < 0.05). Conclusion Preoperative lumbar sagittal morphology needs to be considered when selecting the optimal osteotomy plane. An osteotomy can achieve the greatest success in patients with lumbar kyphosis at L2/L3; for patients with lumbar lordosis, it can achieve satisfactory outcomes at T12/L1.

Mini‐open Pedicle Subtraction Osteotomy versus Standard Posterior Approach for Ankylosing Spondylitis‐related Spinal Kyphosis: A Comparative Study

“…Zhang et al . 31 demonstrated that PSO at L2/L3 achieved the greatest corrective success in patients with AS with lumbar kyphosis. We also assumed that PSO using the MI technique would be more suitable at the L2/L3 level.…”

“…This allowed for consideration of the correction of thoracolumbar kyphosis and reconstruction of the lumbar lordosis. Zhang et al 31 demonstrated that PSO at L2/L3 achieved the greatest corrective success in patients with AS with lumbar kyphosis. We also assumed that PSO using the MI technique would be more suitable at the L2/L3 level.…”

Comparison of pedicle subtraction osteotomy and vertebral column decancellation for the correction of thoracolumbar kyphotic deformity in ankylosing spondylitis: a systematic review and meta-analysis

“…Most PSOs reported in the literature are generally performed in the apical lumbar lordosis region (L2 or L3), and single-level PSOs can achieve an average of 30°–40° correction. 23 , 26 Xu et al 27 compared the data of patients with AS kyphotic deformity treated with single-level PSO and 2-level PSO, and pointed out that 2-level PSO had a better orthopedic effect for patients with severe thoracolumbar kyphosis and LL loss. These authors also noted that although operation time and intraoperative blood loss were greater for 2-level osteotomy than for single-level osteotomy, there was no significant difference in the incidence rate of complications between the two groups.…”