1Spine Surgery, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing; and.
2Medical School of Nanjing University, Nanjing, China.
Neurosurg Focus. 2021 Oct;51(4):E7. doi: 10.3171/2021.7.FOCUS21146.
The aim of this study was to analyze the specific patterns and risk factors of sagittal reconstruction failure in ankylosing spondylitis (AS)-related thoracolumbar kyphosis after pedicle subtraction osteotomy (PSO).
A retrospective study was performed in patients with AS and thoracolumbar kyphosis after lumbar PSO with a minimum follow-up of 2 years. Patients were classified as having successful realignment (group A), inadequate correction immediately postoperatively (group B), and sagittal decompensation during follow-up (group C) according to the immediately postoperative and latest follow-up sagittal vertical axis (SVA). Radiographic parameters and clinical outcomes were collected. Pelvic tilt (PT) was used to assess the magnitude of pelvic backward rotation. Hip structural damage and ossification of the anterior longitudinal ligament (ALL) at the proximal junction, PSO level, and distal junction were also evaluated on radiographs.
Overall, 109 patients with a mean age of 35.3 years were included. Patients in both group B (n = 16) and group C (n = 13) were older than those in group A (n = 80) (mean ages 43.6 vs 32.9 years, p < 0.011; and 39.2 vs 32.9 years, p = 0.018; respectively). Age (OR 1.102, p = 0.011), and preoperative PT (OR 1.171, p = 0.041) and SVA (OR 1.041, p = 0.016) were identified as independent risk factors of inadequate correction. Additionally, a higher distribution of patients with adequate ALL ossification at the PSO level was found in group B than in group A (37.5% vs 22.5%, p = 0.003). Age (OR 1.101, p = 0.011) and preoperative SVA (OR 1.013, p = 0.020) were identified as independent risk factors of sagittal decompensation. Furthermore, compared with group A, group C showed a higher distribution of patients with severe hip structural damage (15.4% vs 0, p = 0.018) and higher incidences of rod fracture (RF) (38.5% vs 8.8%, p = 0.011) and pseudarthrosis (15.4% vs 0, p = 0.018). Additionally, the incidence of RF (19.6% vs 6.9%, p = 0.045) and changes in the proximal junctional angle (0.5° vs 2.2°, p = 0.027) and the distal junctional angle (0.3° vs 2.2°, p = 0.019) were lower during follow-up in patients with adequate ALL ossification than in those without adequate ossification.
Sagittal reconstruction failure in patients with AS could be attributed to inadequate correction immediately after surgery (14.7%) and sagittal decompensation during follow-up (11.9%). Adequate ALL ossification was a risk factor of inadequate correction. However, adequate ALL ossification could decrease the development of RF and relieve the junctional kyphotic change during follow-up. Older age and greater baseline SVA were independent risk factors for both inadequate correction and sagittal decompensation.
本研究旨在分析强直性脊柱炎（AS）相关胸腰椎后凸畸形经椎弓根截骨术（PSO）后矢状面重建失败的具体模式和危险因素。
回顾性分析了 109 例接受腰椎 PSO 治疗且随访时间至少 2 年的 AS 伴胸腰椎后凸患者的资料。根据术后即刻和末次随访的矢状垂直轴（SVA），将患者分为成功矫正组（A 组）、术后即刻矫正不足组（B 组）和随访期间矢状面失代偿组（C 组）。收集了影像学参数和临床结果。骨盆倾斜角（PT）用于评估骨盆向后旋转的程度。还评估了髋关节结构损伤和近端交界区、PSO 水平和远端交界区的前纵韧带骨化（ALL）。
总体而言，纳入了 109 例患者，平均年龄为 35.3 岁。B 组（n=16）和 C 组（n=13）患者的年龄均大于 A 组（n=80）（平均年龄 43.6 岁比 32.9 岁，p<0.011；39.2 岁比 32.9 岁，p=0.018）。年龄（OR 1.102，p=0.011）和术前 PT（OR 1.171，p=0.041）和 SVA（OR 1.041，p=0.016）是矫正不足的独立危险因素。此外，B 组中 PSO 水平 ALL 骨化程度足够的患者比例高于 A 组（37.5%比 22.5%，p=0.003）。年龄（OR 1.101，p=0.011）和术前 SVA（OR 1.013，p=0.020）是矢状面失代偿的独立危险因素。此外，与 A 组相比，C 组中严重髋关节结构损伤的患者比例更高（15.4%比 0，p=0.018），且发生内固定棒断裂（RF）（38.5%比 8.8%，p=0.011）和假关节（15.4%比 0，p=0.018）的发生率更高。此外，与 ALL 骨化不足的患者相比，ALL 骨化程度足够的患者的 RF 发生率（19.6%比 6.9%，p=0.045）和近端交界区角度（0.5°比 2.2°，p=0.027）以及远端交界区角度（0.3°比 2.2°，p=0.019）在随访期间的变化更小。
AS 患者的矢状面重建失败可能归因于术后即刻矫正不足（14.7%）和随访期间矢状面失代偿（11.9%）。ALL 骨化程度足够是矫正不足的危险因素。然而，ALL 骨化程度足够可降低 RF 的发生，并减轻随访期间的交界区后凸变化。年龄较大和基线 SVA 较大是矫正不足和矢状面失代偿的独立危险因素。
