Multivariate analysis of pedicle screw invasion of the proximal facet joint after lumbar surgery

Abstract

Background: To analyze the risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery.

Methods: From January 2019 to January 2021, 1794 patients with lumbar degenerative disease, such as lumbar disc herniation, lumbar spinal stenosis and lumbar spondylolisthesis, were treated at our hospital. In all, 1221 cases were included. General data (sex, age, BMI), bone mineral density, proximal facet joint angle, degenerative lumbar spondylolisthesis, isthmic lumbar spondylolisthesis and fixed segment in the two groups were recorded. After the operation, vertebral CT of the corresponding surgical segments was performed for three-dimensional reconstruction and evaluation of whether the vertebral arch root screw interfered with the proximal facet joint. The included cases were divided into an invasion group and a noninvasion group. Univariate analysis was used to screen the risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery, and the selected risk factors were included in the logistic model for multivariate analysis.

Results: The single-factor analysis showed a significant difference in age, BMI, proximal facet joint angle, degenerative lumbar spondylolisthesis, and fixed segment (P < 0.1). Multifactor analysis of the logistic model showed a significant difference for age ≥ 50 years (P < 0.001, OR = 2.291), BMI > 28 kg/m2 (P < 0.001, OR = 2.548), degenerative lumbar spondylolisthesis (P < 0.001, OR = 2.187), gorge cleft lumbar relaxation (P < 0.001, OR = 2.410), proximal facet joint angle (35 ~ 45°: P < 0.001, OR = 3.151; > 45°: P < 0.001, OR = 3.578), and fixed segment (lower lumbar spine: P < 0.001, OR = 2.912).

Conclusion: Age (≥ 50 years old), BMI (> 28 kg/m2), proximal facet joint angle (35 ~ 45°, > 45°), degenerative lumbar spondylolisthesis, isthmic lumbar spondylolisthesis and fixed segment (lower lumbar spine) are independent risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery. Compared with degenerative lumbar spondylolisthesis, facet joint intrusion is more likely in isthmic lumbar spondylolisthesis.

Keywords: Lumbar surgery; Multivariate analysis; Pedicle screw; Proximal facet joint.

Fig. 1

Li Moumou, a 63-year-old female, was diagnosed with degenerative lumbar spondylolisthesis and underwent posterior decompression, bone grafting, fusion and internal fixation at our hospital. A, B: L4 vertebral body spondylolisthesis (I°) before the operation. C: Preoperative CT showing lumbar degenerative changes and L4 spondylolisthesis (I°). D: Preoperative MRI showing L4 spondylolisthesis (I°), degeneration and bulging of L2-3, L3-4 and L4-5 intervertebral discs, and compression of the dural sac at the corresponding levels. E, F: X-ray showing the position of internal fixation of the lumbar spine 2 months after the operation. G: According to Herren’s grading method, the left screw showed no invasion of the proximal facet joint (grade 0); the right screw showed obvious entry of the articular cavity of the proximal facet joint (grade 2)