Balancing Kyphosis, Pedicle Subtraction Osteotomy and Proximal Junctional Kyphosis

Introduction: Pedicle Subtraction Osteotomy (PSO) is a surgical technique used to correct spinal deformities by excising wedge-shaped portions of vertebral bodies. Proximal Junctional Kyphosis (PJK) is characterized by abnormal curvature at the junction of fused, instrumented spinal segments , contributing to pain and functional limitations. Risk factors for PJK include osteoporosis, high BMI, smoking, paravertebral muscle degeneration, and extensive spinal-pelvic fusion.

Methods: A retrospective review of spinal deformity surgeries at our tertiary care center from 2016 to 2023 was conducted. Data on surgical approaches, complications, and PJK incidence were collected from radiology reports and post-operative clinic records. Patients were followed for an average of 1.6 years (range: 17 days to 6 years), and statistical analyses were performed using SPSS.

Results: Among 264 patients analyzed, 43 underwent PSO at the L3 and L4 vertebral levels (16.3%). PJK developed in 3 patients (7.0%) who had undergone PSO compared to 20 patients (9.0%) without PSO (Pearson χ^2 = 0.195, df=1, p=0.659). The odds ratio for developing PJK with PSO versus without PSO was 0.75 (95% CI 0.214-2.657), indicating no significant association.

Conclusion : In our cohort, PSO does not appear to significantly increase the risk of PJK development. Although there was a slightly higher incidence of PJK at the L3 level compared to L4 level. PSO did not demonstrate a protective effect against PJK. Further studies are warranted to elucidate the relationship between PSO and PJK and to refine surgical strategies for managing spinal deformities effectively.