The Impact of the Thoracolumbar Junction Distraction Technique on Reducing Proximal Junctional Kyphosis: A Comparative Pre- and Post-Implementation Study in Adult Spinal Deformity Surgery

<i>Background and Objectives</i>: Proximal junctional kyphosis (PJK) remains a significant complication in adult spinal deformity (ASD) surgery, often resulting in severe clinical consequences. This study evaluates the effectiveness of the thoracolumbar junction (TLJ) distraction technique in reducing PJK incidence, with a focus on its potential to preserve sagittal alignment and mitigate mechanical stress at the proximal junction. <i>Materials and Methods</i>: This retrospective cohort study included 122 patients who underwent ASD surgery between February 2018 and June 2022. Patients were stratified into a control group and an intervention group based on the application of the TLJ distraction technique. Radiographic and clinical outcomes, including proximal junctional angle (PJA), thoracolumbar angle (TLA), and PJK incidence, were assessed one year postoperatively. Statistical analyses were performed using <i>t</i>-tests and chi-square tests. <i>Results</i>: The incidence of PJK was significantly lower in the intervention group compared with that in the control group (24.6% vs. 44.3%, <i>p</i> = 0.036). Additionally, the intervention group exhibited a significant reduction in postoperative TLA (-10.6° ± 6.3° vs. -6.8° ± 6.8°, <i>p</i> = 0.002) and ΔTLA (2.6° ± 9.0° vs. -2.4° ± 9.5°, <i>p</i> = 0.003). Although improvements in radiographic parameters were associated with a trend toward reduced rates of proximal junctional failure (PJF), statistical significance was not achieved. <i>Conclusions</i>: The TLJ distraction technique effectively reduces PJK incidence by optimizing thoracolumbar alignment and minimizing abrupt sagittal transitions. This simple and reproducible approach presents a promising strategy for mitigating proximal junctional complications in ASD surgery, warranting further validation in multicenter trials.