Abstract
INTRODUCTION: Proximal junctional kyphosis (PJK) in patients undergoing instrumented deformity correction surgery for adult spinal deformity (ASD) is found to be multifactorial. This review aims to provide comprehensive information on which factors affect PJK in ASD correction surgery including prevention strategies. MATERIALS AND METHODS: A literature review was conducted through a web search on PubMed with the following combination keywords: "proximal junctional kyphosis," "adult spinal deformity," and "risk factor" between January 2001 and June 2024. Primary outcomes of interest were divided into two groups: non-radiological parameters including patient characteristics and surgical techniques, and radiological parameters. RESULTS: The non-radiological parameters associated with PJK included age, body mass index, comorbidities, low bone quality, muscle degeneration, combined anterior-posterior surgical approach, rigid proximal instrumentation, upper instrumented vertebrae (UIV) selection in the junctional zone, long-segment fusion, and overcorrection. Moreover, lumbar lordosis, spinopelvic parameter, thoracic tilt, upper instrumented vertebra-femoral angle, fused spinopelvic angle, and UIV inclination were found to be the radiological parameters that influence the incidence of PJK in patient with ASD correction surgery. CONCLUSIONS: Understanding the multifactorial aspects of PJK could aid in the preoperative planning and assessment for patients with ASD. Furthermore, the proposed correction should be based on an individualized approach.