Single and Multilevel Lumbar Total Disc Replacement Adjacent to L5-S1 ALIF (Lumbar Hybrid): 6 Years of Follow-up

Background Single and multilevel lumbar arthroplasty has had excellent results, but the L5-S1 level frequently has pathology that precludes arthroplasty. This study evaluated clinical outcomes and sagittal range of motion (ROM) of operated levels and adjacent motion segments in single- and multiple-level ProDisc-L above a simultaneous L5-S1 fusion (hybrid) after a 2- to 6-year follow-up.

Methods In this prospective cohort study, 46 patients underwent simultaneous lumbar total disc replacement (TDR) at one to three levels and anterior lumbar interbody fusion (ALIF) at L5-S1. Twenty-three patients had L5-S1 ALIF + L4-5 TDR, 19 patients had L5-S1 ALIF + two-level TDR, and 4 patients had L5-S1 ALIF + three-level TDR. Oswestry disability index (ODI) and visual analog scores (VAS) of patient satisfaction (VAS-S) and pain (VAS-P) were recorded. Sagittal motion on pre- and postoperative lumbar radiographs at each operative segment and adjacent segment was acquired. Patients were evaluated preoperatively and at 6 weeks, 3 months, 6 months, and annually for 24 to 72 months postoperatively.

Results For clinical results, there were no differences among the groups for age, gender, body mass index, tobacco use, or worker's compensation status. At 2–6 years postoperation, all patients had significant reductions in ODI and VAS scores. For radiographic results, at the nonsurgical level adjacent to the TDR + ALIF constructs, the mean preoperative ROM was 9.40 ± 1.80° compared with 10.50 ± 2.25° postoperatively. The mean preoperative ROM at levels undergoing TDR was 10.4 ± 2.71° versus 12.6 ± 2.25° postoperatively. There was no statistically significant difference in ROM at each prosthetic motion segment between patients receiving one-, two-, or three-level TDR. The mean preoperative ROM at the L5-S1 segment to undergo fusion was 2.4 ± 2.44°, with all patients having a postoperative ROM of 0.00°.

Conclusions Multilevel TDR above an L5-S1 ALIF (hybrid procedure) preserves ROM at the individual TDR levels and does not reduce the fusion rate of the L5-S1 fused level. Most significantly, the nonoperative adjacent level maintains its preoperative ROM at 2–6 years postoperatively.