Risk Factor Analysis for Proximal Junctional Kyphosis in Neuromuscular Scoliosis: A Single-Center Study

Area of Science:

• Spine surgery
• Orthopedics
• Biomechanical engineering

Background:

• Proximal junctional kyphosis (PJK) is a common complication after corrective spinal surgery for neuromuscular scoliosis (NMS).
• The multifactorial etiology of PJK is not fully understood, but potential risk factors include preoperative hyperkyphosis, spinous process resection, and rod contouring.
• Understanding these factors is crucial for improving surgical outcomes.

Purpose of the Study:

• To identify and validate risk factors for proximal junctional kyphosis (PJK) in patients with neuromuscular scoliosis (NMS) undergoing posterior spinal fusion.
• To correlate specific surgical and radiographic parameters with the development of PJK.

Main Methods:

• Retrospective analysis of 99 NMS patients who underwent posterior spinal fusion.
• Radiographic assessments (preoperative, postoperative, and follow-up) including Cobb angles, thoracic kyphosis (TK), and sagittal alignment parameters.
• Evaluation of clinical variables and surgical parameters such as spinous process resection and rod contour angle (RCA).

Main Results:

• The overall incidence of PJK was 23.2%.
• Spinous process resection was significantly associated with PJK development.
• Higher preoperative TK, greater RCA, and a larger postoperative mismatch between proximal junctional angle (PJA) and RCA were significantly associated with PJK.

Conclusions:

• Spinous process resection, excessive rod bending (high RCA), and severe preoperative thoracic hyperkyphosis are significant risk factors for PJK in NMS patients.
• A pronounced mismatch between postoperative PJA and RCA is also a key predictor of PJK.
• These factors must be carefully considered during surgical planning and execution for NMS deformity correction to minimize PJK risk.