Posterior Ligamentous Augmentation is Associated with Reduced Proximal Junctional Kyphosis and Failure Rates in Adult Spinal Deformity Surgery: a Systematic Review and Meta-analysis of 1,333 patients

Introduction: Adult spinal deformity (ASD) surgery can lead to proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). The rates of PJK and PJF vary across the literature from 17-61.7%. Posterior ligamentous augmentation (PLA) with spinous process or sublaminar tethering at upper instrumented vertebra (UIV) +1 or +2, have been studied as potential techniques to prevent PJK and PJF.

Methods: A systematic literature review and meta-analysis was performed according to the PRISMA guidelines. The majority of the studies defined PJK as increase of ≥10° in sagittal Cobb angle from UIV to UIV+2 compared to preop. Need for revision surgery for PJK was defined as PJF.

Results: Eight comparative studies in total were included, comprising 1,333 patients (PLA: 579; no PLA: 754). Mean age ranged between 55-68.6 years across the included studies. The mean follow-up ranged between 17.6-31.2 months. Age was similar between the two groups (MD 2.53; 95%CI -0.28- 5.34, I2:64.8%). No differences were identified between the two groups in terms of BMI (MD 1.03; 95%CI -0.87- 2.93, I2:69%). Pre-operative and post-operative SVA were similar between the PLA and no PLA groups; pre-op SVA (MD 3.92; 95%CI -1.90- 9.75, I2:73.1%) and post-op SVA (MD -1.54; 95%CI -4.10- 1.01, I2:56.2%). The PLA group was associated with statistically significant lower odds of developing PJK compared to no PLA (PLA: 25.8%; no PLA: 28.8%, OR: 0.54, 95% CI 0.34-0.85, I2=37.4%). In addition, the PLA group was also associated with statistically significant lower odds of PJF (PLA: 3.3%; no PLA: 12.3%; OR: 0.23, 95% CI 0.12-0.47, I2=17.9%).

Conclusion : Use of spinous process or sublaminar tethering for ASD was associated with statistically significant lowed odds of developing PJK and PJF over a follow-up that ranged between 17.6-31.2 months.