439 - Outcomes of Single Level Total Disc Arthroplasty for Lumbar Degenerati...

General Session: Arthroplasty - Hall F

Presented by: M. Scott-Young

Author(s):

M. Scott-Young(1), L. McEntee(1), B. Schram(2), J. Furness(2), E. Ralthbone(2), M. Zotti(1), W. Hing(2)

(1) Gold Coast Spine, Southport, QLD, Australia
(2) Bond University, Faculty of Health Sciences and Medicine, Gold Coast, QLD, Australia

Abstract

Total disc arthroplasty (TDA) is effective for the treatment of lumbar degenerative disc disease (LDDD) in carefully selected patients. Studies demonstrate high patient satisfaction and improvement of outcomes compared to pre-operative status but have short follow-up or small cohort sizes. The aim of this study is to assess the short and mid-term outcomes and satisfaction of a large cohort of patients with one level LDDD treated with TDA. Data collected prospectively in a dual surgeon practice concerning single level TDA performed via an anterior approach was included. Time periods for assessment were pre-operative, then post-operative at 3, 6- and 12- months with yearly follow-up thereafter. Patient reported outcomes measured were patient satisfaction, visual analogue score back (VAS-B) and leg (VAS-L), Oswestry Disability Index (ODI) and Roland Morris Disability Questionnaire (RMDQ). A total of 402 patients (238 males, 164 females) who underwent single level lumbar TDA between June 1997 and December 2015 were included in this study. The average age was 41 (range: 16-78) and mean follow-up 4.1 years (range: 1-10). The levels were L5-S1 (318, 80%), L4-5 (81, 20%) & L3-4 (3, 1%). Implants used were Charité (DePuy Spine, Raynham, MA, USA; n=144), InMotion (DePuy Spine, Raynham, MA, USA; n=100), LP-ESP (FH Industrie, Quimper, France; n=67), ProDisc (DePuy Spine, Raynham, MA, USA; n=60) and other implants in 30 patients. Compared to pre-operative scoring, postoperative cohort means for outcomes at each timepoint revealed significant improvements (all p< 0.001). Percentage improvement between pre-operative and final available scores were VAS-B 68%, VAS-L 50%, RMDQ 80% and ODI 76%. 93.5% of patients reported either good (n=51) or excellent satisfaction (n=323) with treatment at final review. Regression analysis of cohort mean scores revealed steady-state scores reached by 12 months. While VAS-B and VAS-L recorded maximum improvement in cohort means by 3 months, ODI and RMDQ continued to improve until 6 and 12 months, respectively. The mean preoperative outcome scores were: VAS-B 68.7 (95%C.I. 66.3-71.0), VAS-L 49.6 (95%CI 46.3-53.2) RMDQ 15.6 (95%CI 15.1-16.1) and ODI 45.7 (95%CI 44-47.2). The mean postoperative outcomes scores at two years: VAS-B 14.2 (95%CI 12.1-16.3), VAS-L 11.8 (95%CI 9.9-13.7), RMDQ 2.3 (95%CI 2-2.6), ODI 10.3 (95%CI 9.0-11.6). Mid-term outcomes (7-10 years) were available in 222 of 402 (56%) patients. The average outcomes during this period were: VAS-B 20.0 (95%CI 18.1-21.9), VAS-L 12.4 (95%CI 10.5-14.3), RMDQ 3.0 (95%CI 2.7-3.3), ODI 11.8 (95%CI 10.8-12.8). There was no decay of outcomes in the mid-term with no statistically significant differences between 2 year outcomes compared to 7, 8, 9 & 10 year outcomes for ODI, VAS-L and RMDQ. However, there was a significant difference demonstrated in VAS-B between cohort means that did not reach minimum clinically important difference when comparing 2 year (mean 17.8/100) and 7-10 year means (mean 20.0/100) [p=0.004]. This study of a large cohort suggests that single level lumbar TDA in selected patients is associated with improved outcomes compared to baseline and good or excellent treatment satisfaction in the majority. The majority of patients reach a level of improvement in all measured outcomes by 12 months that is sustained to mid-term follow-up. Further study to define long-term outcomes and survivorship are required.