Rod Contour Angle and Postoperative Thoracic Kyphosis: Key Predictors of Proximal Junctional Kyphosis in Pediatric Neuromuscular Scoliosis after Spinopelvic Fusion

Study DesignRetrospective cohort study.ObjectivesProximal junctional kyphosis (PJK) is a postoperative complication in spinal deformity surgery causing pain, functional deterioration, and potential revision surgery, with challenges in the neuromuscular scoliosis (NMS) population. We investigated the incidence, risk factors, and clinical impact of PJK in nonambulatory pediatric NMS patients following spinopelvic fusion.MethodsSeventy-two NMS patients who underwent spinopelvic fusion from the upper thoracic vertebra to the pelvis were reviewed, with a minimum 2-year follow-up. Radiographic measurements and clinical data were analyzed to identify PJK predictors and evaluate outcomes. PJK was defined as a proximal junctional angle (PJA) ≥10° and an increase of ≥10° from preoperative measurements. Statistical analyses included t-tests, ROC curve analysis, logistic regression, and linear regression.ResultsThe incidence of PJK was 25%. Significant predictors included rod contour angle (RCA) (odds ratio [OR]: 1.11, <i>P</i> = 0.04), postoperative T2-T12 kyphosis (OR: 1.04, <i>P</i> = 0.043), and the difference between postoperative T2-T12 kyphosis and RCA (OR: 1.04, <i>P</i> = 0.021). A bidirectional relationship between pre- and postoperative PJA was observed. Lower preoperative PJA was associated with an increased risk of PJK (area under the curve [AUC]: 0.78, <i>P</i> < 0.001). Conversely, high preoperative PJA tended to decrease after surgery. No revision surgeries were performed for PJK.ConclusionThis study reveals a 25% incidence of PJK in NMS patients undergoing spinopelvic fusion. Preoperative radiographic evaluation warrants particular attention in cases exhibiting decreased PJA values. Furthermore, meticulous intraoperative optimization of PJA, RCA, and thoracic kyphosis appears crucial for minimizing PJK occurrence.