Introduction: Evaluation of the determinants of widely varying regional rates of lumbar fusion is needed. While patient, surgeon, and setting-specific factors have been investigated; the association of between decision making and the quality of the underlying evidence remains unclear. This study therefore aimed to evaluate the influence of the quality of evidence on experts’ decision to perform lumbar fusion for degenerative indications.
Methods: The quality of evidence underlying 1296 distinct degenerative indications for lumbar fusion was graded according to criteria developed by the North American Spine Society. A North American expert panel of 13 physicians was convened and members were provided with scenario-specific evidence grades and a systematic literature review evaluating the safety and efficacy of lumbar fusion. Using a modified Delphi process, panel members rated the appropriateness of lumbar fusion for each indication. The strength of association between expert panel disagreement and scenarios’ clinical characteristics, radiologic findings, and levels of evidence was assessed.
Results: In the 1296 scenarios evaluated, 13% were supported by level I evidence, 33% by level II evidence, and 54% by level III evidence. Indications involving spondylolisthesis were associated with the highest percentage of level I evidence (Fig. 1). Increasing quality of evidence was not associated with decreasing disagreement when panelists considered lumbar fusion for spinal stenosis (P=0.11), spondylolisthesis (P=0.79), disc herniation (P=1.0), or spondylosis (P=0.63) (Fig. 2). In contrast, disagreement among panelists was dependent upon the extent of patients’ disability (P<0.001), form of low back pain (P<0.001), severity of neurologic signs and symptoms (P<0.001), and radiologic findings (P<0.001) (Fig. 3).
Conclusions: The quality of underlying evidence for lumbar fusion did not account for differing surgical decision making. The reliance on level III evidence for the majority of surgical indications may limit the use of the available literature in patient care decisions. (Funded by the Alberta Spine Foundation.)
Patient Care: Research efforts focused on indications for lumbar fusion where currently only low-level evidence exists would both reduce practice variation and improve patient outcomes.
Learning Objectives: By the conclusion of the session, participants should be able to: 1) Describe the quality of available evidence in support of lumbar fusion for degenerative indications; 2) Discuss, in small groups the determinants of varying surgical decision making; 3) Identify indications for lumbar fusion where inadequate evidence is available to support patient care decisions.