Risk Assessment and Management Options for Proximal Junctional Kyphosis: A Systematic Review

Proximal junctional kyphosis (PJK) is an alignment loss above an instrumented vertebra. We hypothesize that careful pre-operative consideration of major procedures and risk factors associated with development of PJK will minimize the likelihood of vertebral instability, functional and neurological complications, and need for revision surgery. The authors performed a systematic search of published literature in the PubMed, Web of Science, and Cochrane Library databases from January 01, 2012, to December 31, 2023, per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. This retrospective analysis included 1304 pediatric and 1101 adult patients from articles published between 2012 - 2023 in PubMed, Web of Science, and Cochrane databases using search terms “proximal junctional kyphosis”, “proximal junctional failure”, and “scoliosis”. Eligible studies included randomized controlled trials and other clinical studies with a minimum of two-year follow-up and a sample size of at least 30 patients. Nine surgical procedures and eight risk factors were determined to significantly contribute to the development of PJK. The two procedures with the greatest association with post-operative development of PJK in pediatrics are posterior interbody fusions (45.5%, P < 0.01) and rib-based proximal anchors (24.7%, P = 0.03). The highest-risk adult spine procedures include tetherless procedures (60.7%, P = 0.0002) and lower thoracic junctional tethers (31.5%, P < 0.001). The two greatest risk factors for the development of PJK in pediatrics are increased rod-contouring angle (65%, P < 0.001) and increased spinopelvic malalignment (40%, P = 0.04). PJK has significant implications on surgical outcomes, leading to further functional and neurologic side effects and potentially proximal junctional failure. Spine surgeons should consider the risk factors while selecting a procedure to minimize the likelihood of developing PJK in spinal deformity patients.