JAAOS - 2026-07-29 - Journal Article
Lumbar Adjacent Segment Disease: A Modern Perspective and Review of the Literature.
Dalton J, Ramanathan R, Hilibrand AS, Vaccaro AR
Topics
Key Takeaway
ASD occurs at 2–3% per year post-lumbar fusion with 20–30% cumulative incidence at 10 years, driven by PI-LL mismatch, BMI, and preexisting adjacent-level degeneration.
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Summary
This narrative review synthesizes current evidence on the pathogenesis, risk factors, and management of ASD following lumbar fusion. Key modifiable risk factors include elevated BMI, preoperative adjacent-level degeneration, and PI-LL mismatch; MIS and robotic-assisted techniques are proposed to reduce ASD incidence but long-term comparative data remain inconclusive. Emerging biologic therapies and advanced imaging are identified as potential tools for earlier detection and prevention.
Key Limitation
As a narrative review without meta-analytic methodology, conclusions about comparative efficacy of MIS versus open fusion or robotic instrumentation for ASD prevention are not supported by pooled effect sizes.
Original Abstract
Our collective understanding of the pathogenesis, risk factors, and management of adjacent segment disease (ASD) following lumbar fusion has expanded markedly in recent years, necessitating an updated and comprehensive review. ASD is now recognized as a multifactorial process in which postoperative biomechanical changes accelerate degeneration, further amplified by predisposing genetic factors. Key risk factors have been identified and linked to increased rates of ASD, including elevated body mass index, preexisting degeneration at adjacent levels, and inadequate restoration of sagittal alignment, particularly pelvic incidence-lumbar lordosis mismatch. Innovative surgical techniques, including minimally invasive approaches and robotic-assisted instrumentation, have been increasingly used and researched over the past decade with the goal of reducing the incidence and progression of ASD, although long-term evidence remains mixed. Although these advancements are promising, it is important to evaluate their efficacy, limitations, indications, and contraindications using the most current available evidence. Finally, advances in diagnostic imaging and emerging biologic therapies represent a potential paradigm shift in our understanding of the pathogenesis and preventability of ASD.