Abstract
Introduction Fusion has been the primary treatment for symptomatic disc degeneration unresponsive to non-operative care. The results for two-level fusion have generally been worse than for one-level. There is little information available concerning two-level total disc replacement (TDR), and none comes from prospective studies. The purpose of this study was to analyse the results of two-level disc replacement and compare these results to single-level cases performed at the same centre.
Methods This data was collected from a single center participating in a multicentre a prospective, FDA-regulated clinical trial evaluating the ProDisc. This study is based on data from the first 105 patients (36 2-level and 69 one-level) enrolled who have reached a minimum of 12 months follow-up (data for 18 and 24 month were included if available at the time of data analysis). All patients were treated for symptomatic disc degeneration unresponsive to non-operative care. Data were collected pre-, peri-, and 6 weeks and 3, 6, 12, 18, and 24 months post-operatively. Outcome data included visual analog scale (VAS) assessing pain, Oswestry Disability Questionnaire, patient satisfaction (VAS ranging from 0 to 10), and a question asking patients if they would have the same surgery again. Within the 1-level and 2-level subgroups, pre- and postoperative data were compared to determine if there was improvement. The percentage of change in the pre- to post-operative scores was compared to determine if there were differences between the 1- and 2-level subgroups.
Results The mean estimated blood loss (1-level= 57.7 cc vs. 2-level = 76.7 cc), operative time (1-level = 61.6 min vs. 2-level = 96.7 min) and length of hospitalization (1-level=1.86 days vs. 2-level= 2.36 days) were significantly less in the single-level cases (p< 0.05). VAS pain scores improved significantly (p< 0.05) in 1- and 2-level cases. The mean improvement in 2-level cases was 58.7% and in 1-level cases 62.4% (p> 0.05). Between the one and two-level cases, there was no significant difference in the percentage of patients who would have the surgery again (86.6% vs. 77.8%; p> 0.05). The mean satisfaction score in the single-level TDR group was 8.2 and was 7.1 in the 2-level group (maximum score of 10).
Discussion This study found that both 1- and 2-level TDR results in significant improvement in pain and function scores. Patients undergoing 2-level disc replacement yielded outcomes similar to 1-level cases. These results support TDR as a viable treatment for 2-level symptomatic disc degeneration.
The abstracts were prepared by Assoc Prof Bruce McPhee. Correspondence should be addressed to him at the Division of Orthopaedics, The University of Queensland, Clinical Sciences Building, Royal Brisbane Hospital, Herston, Brisbane, 4029, Australia.
