170 - Two-year Patient Outcomes after Single vs. Multi-level Cervical Disc A...

#170 Two-year Patient Outcomes after Single vs. Multi-level Cervical Disc Arthroplasty

Oral Posters: Cervical

Presented by: M. Gornet

Author(s):

M.F. Gornet (1)
F.W. Schranck (1)
B.A. Taylor (1)
B. Kopjar (2)

(1) The Orthopedic Center of Saint Louis, Spine Research Center, Saint Louis, MO, USA
(2) University of Washington Seattle, Department of Health Services, Seattle, WA, USA

Abstract

Introduction: Cervical disc arthroplasty (CDA), FDA-approved at a single level, is an alternative for up to 40% of anterior cervical discectomy and fusion candidates. There is little research evidence regarding the outcomes of multi-level CDA patients.

Methods: Independent statistical analysis of prospectively collected patient-reported outcomes data for single- and multi-level CDA patients (75 in-hospital and 129 at ambulatory surgery center) treated by two fellowship-trained spine surgeons.

Results: Patients (N=204) included 119 single-level and 87 multi-level (67 two-level, 17 three-level and 1 four-level). Follow-up rate at two years was 81%. There were more women in the single-level cohort than in the multi-level cohort (47% and 36%, respectively, p>0.05). Single-level patients were younger than multi-level patients (43.4 (SD,9.0) and 47.3 years (SD,8.1), respectively, P=0.0018). 64.7% of the single-level cases and 77.0% of the multi-level cases involved workers' compensation claims (P=0.0572). 48.5% of patients smoked tobacco preoperatively, but there were no differences between groups. Operative time was 104.6 (SD = 30.5) minutes in the multi-level cohort and 66.9 (SD, 16.7) for single-level cases (P< 0.0001). Single-level cases had worse baseline Neck Disability Index (NDI) than multi-level cases (58.3 and 50.2, respectively, P< 0.0001). There was a significant improvement in NDI at 1 and 2 years follow up (P< 0.0001). Mean NDI at 12 and 24 months was 25.8 (SD, 19.8) and 25.7 (SD, 19.2), respectively, At 1 and 2 years follow-up there were no significant differences in NDI between the groups. Adjustment for baseline confounders did not have a measurable impact on the results. Single-level cases also had worse baseline numeric neck pain scores than multi-level cases (7.6 and 6.8, respectively, P< 0.0001). At 1 and 2 years follow-up there were no significant differences in neck pain between the groups. The average neck pain score at 12 and 24 months was 2.8 (SD,2.4) and 2.9 (SD,2.5), respectively, demonstrating significant improvement from preoperative (P< 0.0001). Adjustment for baseline confounders did not have a measurable impact on neck pain results. The average SF-36 PCS at baseline was 32.0 (SD,7.0). There were no statistically significant differences between the cohorts preoperatively. The SF-36 PCS improved to 42.1 (SD,11.2) at 12 months and 41.9 (SD,11.4) at 24 months (P< 0.0001). There were no significant differences in the improvement between the two cohorts. The average SF-36 MCS at baseline was 39.5 (SD,12.2). There were no statistically significant differences between the cohorts. The SF-36 MCS improved to 48.3 (SD,11.7) at 12 months and 47.4 (SD,12.9) at 24 months (P< 0.0001). There were no significant differences in the improvement between the two cohorts. By two-year follow-up, re-operation occurred in three (2.5%) single-level cases (one removal due to trauma and two re-operations at another level) and three (3.5%) multi-level cases (two removals and one decompression) (P=0.6959). Early postoperative return to work occurred in both groups.

Conclusion: Two years after CDA, improvement in pain, functional and health related quality of life patient-reported outcomes was significant for both single and multi-level CDA patients in this large consecutive case series. Multi-level CDA appeared to be as safe and effective as single-level CDA in this study. Results need to be interpreted in light of non-randomized comparisons.