Multiple-Level Lumbar Total Disk Replacement: A Prospective Clinical and Radiographic Analysis of Motion Preservation at 24-72 Months.

Abstract

Recent studies demonstrate the efficacy of lumbar arthroplasty using the ProDisc-L. Patients frequently present with multilevel pathology and may be candidates for multilevel disk replacement. To evaluate clinical outcomes and sagittal range of motion of operated levels and adjacent lumbar motion segments in multiple-level ProDisc-L constructs after 2-6 years follow-up. A total of 159 patients underwent adjacent 2-level (n=114), 3-level (n=41), or 4-level (n=4) lumbar total disk replacement (TDR). This is a prospective cohort. Clinical measures: Oswestry Disability Index and Visual Analog Score of patient satisfaction (VAS-S) and pain (VAS-P) data were collected. Radiographic measures: sagittal motion on preoperative and postoperative lumbar radiographs at each operative segment and adjacent segment. Patients were evaluated with radiographic and clinical outcomes measures preoperatively, at 6 weeks, 3 months, 6 months, and annually for 24-72 months postoperatively. Radiographic: at the motion segment adjacent to the TDR, mean preoperative range of motion (ROM) was 8.20±2.88 degrees, compared with 8.40±2.4 degrees postoperatively at last follow-up (P>0.05). Between the 3 TDR groups, there were no significant differences in ROM at any time point except at L5-S1. Across both groups for TDR motion segments, the mean preoperative ROM was 10.15±2.71 versus 12.30±2.25 degrees postoperatively (P=0.011) at last follow-up. At L5-S1 mean preoperative motion was 7.60±3.90 versus 5.81±3.1 degrees postoperatively (P=0.60). Clinical: at 24-72 months postoperatively, all patients had significant reductions in Oswestry Disability Index, VAS-P, and VAS-S scores (P<0.05). At up to 72 months of follow-up, no patient underwent adjacent-level surgery but there were 3 cases of index-level revision surgery. Multilevel TDR preserves ROM at the individual TDR levels. Most significantly, the nonoperative adjacent level maintains its preoperative ROM at 2-6 years postoperatively. At up to 6 years of follow-up, there has been no need for revision or adjacent-segment surgery. Patients also demonstrate significant improvement in pain and disability at latest follow-up.