General Session: Cervical Motion Preservation
Presented by: J. Zigler - View Audio/Video Presentation (Members Only)
(1) Texas Back Institute, Spine Surgery, Plano, TX, United States
Background: Total disc replacement (TDR) is an alternative to fusion in patients with lumbar degenerative disc disease. Long term data comparing mobile core disc (MCD) vs. constrained core disc (CCD) TDR implants are lacking. The purpose of this study was to compare five year clinical and radiographic outcomes following lumbar TDR with MCD vs. CCD implants.
Methods: Patients diagnosed with degenerative lumbar disc disease were enrolled in a multicenter, prospective, randomized, controlled investigational device exemption trial and were implanted with either a MCD (n=217) or CCD (n=64) device. All patients included in this post-hoc analysis completed their 6 wk, 24 mo and 5 yr follow-up appointments. Clinical outcomes included self-reported back pain using a visual analogue scale (VAS), Oswestry Disability Index (ODI), serious device-related complications, and reoperations. Range of motion at the index level (L4-L5 and L5-S1) was assessed with flexion/extension lateral radiographs of the spine. Clinical and radiographic outcomes were compared between MCD and CCD and were further stratified by index level and endplate angle.
Results: Range of motion (ROM) was significantly greater with MCD vs. CCD at 24 mo (7.1o vs. 4.8o, p< 0.001) and 5 yrs (6.2o vs. 3.8o, p=0.004). Reduction in back pain and ODI post-TDR were not different between MCD and CCD. Reoperation rates were significantly greater following CCD compared to MCD at 5 yrs (p=0.03). There were no differences in the rate of device related serious adverse events. When clinical outcomes were stratified by index level, the reduction in back pain from preoperation levels was significantly greater following MCD vs. CCD for L4-L5 index level procedures at 5 yrs (80% vs. 65%, p=0.042). Greater ROM following MCD was observed at 24 mo (6.8o vs. 5.1o, p=0.013) and 5 yrs (6.1o vs. 3.5o, p=0.005) for L5-S1 index level procedures, and at 24 mo for L4-L5 levels (7.8o vs. 4.1o, p=0.022). Further stratification by endplate angle for L5-S1 index procedures demonstrated significant improvements in back pain and ROM following MCD compared to CCD. For 11o endplates, reduction in back pain was greater with MCD at 6 wk (73% vs. 54%, p=0.049). Endplates with 6o demonstrated greater improvements in ROM at 24 mo (6.7o vs. 4.5o, p=0.012) and 5 yrs (6.0o vs. 3.1o, p=0.005) following MCD vs. CCD.
Conclusions: Clinical and radiographic outcomes five years following lumbar TDR demonstrates maintained motion and improvements in back pain and function. Furthermore, the use of MCD implants provides greater improvements in symptom relief compared to CCD implants.