Study design:

Prospective Cohort Study.

Objective:

The aim of this paper is to compare the mid- to long-term patient-reported outcome measures (PROMs) between single-level total disc arthroplasty (TDA), multi-level TDA, and hybrid constructs (combination of TDA and anterior lumbar interbody fusion (ALIF) across multiple levels) for symptomatic degenerative disc disease (DDD).

Summary of background data:

The treatment of single-level DDD is well documented using TDA. However, there is still a paucity of published evidence regarding long-term outcomes on multi-level TDA and hybrid constructs for the treatment of multi-level DDD, as well as lack of long-term comparisons regarding treatment of single-level DDD and multi-level DDD.

Methods:

950 patients underwent surgery for single-level or multi-level DDD between July 1998 and February 2012 with single-level TDA (n = 211), multi-level TDA (n = 122) or hybrid construct (n = 617). Visual Analog Score for the back (VAS-B) and leg (VAS-L) were recorded, along with the Oswestry Disability Index (ODI) and Roland Morris Disability Questionnaire (RMDQ).

Results:

All PROMs in all groups showed statistically and clinically significant improvements (p < 0.005) in pain and function that is well above the corresponding minimum clinically important difference (MCID) and exceeds literature thresholds for substantial clinical benefit (SCB). Unadjusted analyses show that there were no statistically significant differences in the change scores between the surgery groups for VAS back and leg pain, and RMDQ up to 8 years follow-up. Adjusted analyses showed the ODI improvement score for the single group was 2.2 points better (95%CI: 0.6, 3.9, p = 0.009) than in the hybrid group. The RMDQ change score was better in the hybrid group than in the multi-level group by 1.1 points (95%CI: 0.4, 1.9, p = 0.003) at 6 months and a further 0.4 point at 2 years (95%CI: 0.1, 0.8, p = 0.011).

Conclusions:

In the setting of meticulous pre-operative evaluation in establishing a precision diagnosis, clinically and statistically equivalent results can be achieved when treating symptomatic DDD through single-level TDA, multi-level TDA, and hybrid constructs. These results are sustained at mid- to long-term follow-up.Level of Evidence: 3.