Clinical Outcomes After 1 and 2-Level Lumbar Total Disc Arthroplasty: 1,187 Patients with 7 to 21-Year Follow-up.

BACKGROUND

In this study, we expand the supportive evidence for total disc arthroplasty (TDA) with results up to 21 years in a large patient cohort who received a semiconstrained ball-and-socket lumbar prosthesis. The objectives of the study were to compare the results for 1 versus 2-level surgeries and to evaluate whether prior surgery at the index level(s) impacts clinical outcomes.

METHODS

From 1999 to 2013, 1,187 patients with chronic lumbar degenerative disc disease (DDD) underwent lumbar TDA, of whom 772 underwent a 1-level procedure and 415 underwent a 2-level procedure. A total of 373 (31.4%) of the 1,187 patients had prior index-level surgery. Patients were evaluated preoperatively; at 3, 6, 12, 18, and 24 months postoperatively; and yearly thereafter. The follow-up duration ranged from 7 to 21 years (mean, 11 years and 8 months). Collected data included radiographic, neurological, and physical assessments, as well as self-evaluations using the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain. Perioperative data points, complication rates, and reoperation or revision rates were also assessed. Patients were divided into 4 groups: 1-level TDA with no prior surgery at the index level, 1-level TDA with prior surgery, 2-level TDA with no prior surgery, and 2-level TDA with prior surgery.

RESULTS

All groups showed dramatic reduction in the ODI at 3 months postoperatively and maintained these scores over time. Although VAS pain did not diminish to its final level as rapidly for patients with prior surgery, there was no significant difference between the groups in terms of pain reduction at 24 months postoperatively. Of 1,187 patients, 49 (4.13%) required either a new surgery at another level or revision or reoperation at the index level. Rates were too low in all groups to compare them statistically. Total TDA revision and adjacent-level surgery rates over 7 to 21 years were very low (0.67% and 1.85%, respectively).

CONCLUSIONS

This study demonstrates the robust long-term clinical success of 1 and 2-level lumbar TDA as assessed at 7 to 21 years postoperatively in one of the largest evaluated cohorts of patients with TDA. Patients had dramatic and maintained reductions in disability and pain scores over time and low rates of index-level revision or reoperation and adjacent-level surgery relative to published long-term fusion data. Additionally, patients who underwent 1-level lumbar TDA and those who underwent 2-level TDA demonstrated equivalent improvement, as did patients with prior surgery at the index level and those with no prior surgery.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.