626 - Are the Cervical Spines of “Whiplash” Patients Different?...

Oral Posters: Cervical

Presented by: M.F. Gornet - View Audio/Video Presentation (Members Only)

Author(s):

M.F. Gornet(1), J.A. Hipp(2), A.G. Copay(3), F.W. Schranck(3)

(1) Orthopedic Center of St. Louis, St Louis, MO, United States
(2) Medical Metrics, Inc., Houston, TX, United States
(3) SPIRITT Research, St Louis, MO, United States

Abstract

Introduction: When interviewing patients who are otherwise appropriate candidates for cervical disc arthroplasty (CDA), some patients will report having had “whiplash” in a motor vehicle accident. There is a lack of evidence-based guidance on integrating “whiplash” complaints into surgical decision making. To add to the evidence-base, preoperative intervertebral motion (IVM) metrics and radiographic grading of disc degeneration were analyzed for differences between those patients who reported “whiplash” in their history versus those that did not.

Method: Prospectively collected data for 180 patients that had been treated with CDA and who had both preoperative flexion-extension (F-E) radiographs and clinical outcome scores at preop and 24 months, were grouped by whether they reported “whiplash” in their history, and then retrospectively analyzed for associations between “whiplash” and; IVM metrics, radiographic disc degeneration (Kellgren-Lawrence), and clinical outcomes. The IVM metrics included the Disc Integrity Index (DII = change in disc height between F-E per degree of rotation), and the Quantitative Stability Index (QSI = intervertebral translation between F-E per degree of rotation). All metrics were divided by the amount of intervertebral rotation between F-E to control for variability in patient effort, and were reported as the number of standard deviations from the average found in asymptomatic volunteers. DII was measured at both the anterior- and posterior-most aspects of the disc spaces. Since patients were treated at between 1 and 3 levels, and to account for the possibility of IVM abnormalities at adjacent levels, the maximum DII and QSI at all assessed levels in each patient were analyzed.

Results: There was significantly less radiographic disc degeneration in the patients who reported whiplash (P=0.0005). The anterior DII (P=0.0044) and the QSI (P=0.0008) were significantly greater in whiplash patients (Figure, error bars are the standard error). Two years following surgery, the average change in NDI score relative to PreOp was no different in the whiplash versus non-whiplash patients (-32 versus -29, P=0.62). Using a > 19 point reduction in NDI after 2 years to define a substantial clinical benefit (SCB), 86% of whiplash and 70% of non-whiplash patients had achieved a SCB (P=0.19).

Discussion: The results suggest that there may be some patients who present with complaints of “whiplash”, and who have objectively abnormal disc motion, that may achieve a good result by replacing the damaged disc with a CDA.

DII and QSI