Skip to main content
  • A Sliding-Scale for the Minimum Clinically Important Difference in ODI for Lumbar Spine Surgery

    Final Number:

    Ahilan Sivaganesan MD; Matthew J. McGirt MD; Anthony L. Asher MD FACS; Clinton J. Devin MD

    Study Design:

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2017 Annual Meeting - Late Breaking Science

    Introduction: The achievement of a minimum clinically important difference (MCID) in the Oswestry Disability Index (ODI) has emerged as a prominent proxy for success after lumbar spine surgery. However, it has become clear that patients with low baseline ODI have a more difficult time achieving MCID in ODI, despite being more likely to be satisfied after surgery. Here we present a novel sliding-scale MCID for ODI that is dependent on a patient’s pre-operative ODI.

    Methods: This study included all patients in the Quality and Outcomes Database (QOD) who underwent elective one-level lumbar fusion surgery for degenerative disease between January 2012 and December 2016. We performed a logistic regression analysis with 12-month satisfaction as the outcome, and baseline and 12-month ODI as covariates.

    Results: A total of 2407 patients were included in this study. Our regression model reveals a significantly positive association between baseline ODI and the odds of satisfaction (p < 0.0001) and a significantly negative association between 12-month ODI and satisfaction (p < 0.0001). With bootstrap-based internal validation, the area under the ROC curve for this model is 0.86. Figure 1 is a three-dimensional surface plot which graphically displays the predicted probability of satisfaction in relation to baseline and 12-month ODI . Table 1 lists the minimal ODI improvement necessary for at least a 50% probability of satisfaction, for each decile of baseline ODI, based on that plot.

    Conclusions: There is a clear “goal-line” effect wherein the achievement of MCID for ODI becomes more difficulty as baseline ODI decreases. This highlights the need for an alternative conception of MCID, not as a uniform threshold for every patient, but as a sliding-scale. We present this sliding scale MCID for ODI, in which the threshold value decreases as baseline ODI decreases.

    Patient Care: It will allow for more appropriate and accurate assessments of the efficacy of elective lumbar surgery by tailoring a major outcome metric based on patients' pre-operative disability level.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the relationship between baseline ODI and the ease of achieving traditional MCID for ODI, 2) Discuss the weaknesses of a uniform MCID threshold for all lumbar surgery patients, and 3) Understand the usefulness of a sliding scale MCID threshold as presented here.


We use cookies to improve the performance of our site, to analyze the traffic to our site, and to personalize your experience of the site. You can control cookies through your browser settings. Please find more information on the cookies used on our site. Privacy Policy