106. Seven- to 21-year clinical outcomes of 1,187 patients treated with one- and two-level lumbar total disc arthroplasty

Abstract

<h3>BACKGROUND CONTEXT</h3> Multiple studies have shown that lumbar total disc arthroplasty (TDA) is not only safe and effective in treating chronic lumbar degenerative disc disease (DDD), but also provides a better surgical alternative to fusion with respect to patient-reported results, restoring motion, and reducing reoperation rates and severity of adjacent level degeneration. Published evidence is limited for follow-up past 5-7 years after TDA. In this study, we expand the evidence favoring TDA with results up to 21 years, of a large patient cohort treated with semi-constrained ball-and-socket lumbar TDA. <h3>PURPOSE</h3> To compare the results for one-level vs two-level patients, and evaluate whether prior surgery at these levels has an effect on clinical outcomes. <h3>STUDY DESIGN/SETTING</h3> Retrospective clinical study. <h3>PATIENT SAMPLE</h3> A total of 1,187 chronic lumbar DDD patients (622 male, 565 female, mean age 43±9.81years, range 17-86 years), underwent lumbar TDA from 1999 to 2013. Of the total, 772 patients had one-level and 415 patients had two-level procedures; 373 out of 1,187 patients (31.5%) had prior index-level surgery (recurrent disc herniation or postdiscectomy syndrome). <h3>OUTCOME MEASURES</h3> Data collected included radiographic, neurological/physical assessment, self-evaluation using the Oswestry Disability Index (ODI) and visual analog back and leg pain Scores (VAS). Complication, reoperation/revision rates, and perioperative data points were also assessed. <h3>Methods</h3> Patients were evaluated preoperatively, then followed postoperatively at 3, 6, 12, and 18 months, then yearly thereafter. Patient follow-up ranged between 7 and 21 years (mean 11 years, 8 months). Patients were stratified into one- (1L) and two-level (2L) procedure groups, then divided into prior (PS) or no-prior surgery (NPS) at the index level for data comparison. Patient demographics (age and gender) were comparable for all groups. <h3>Results</h3> All groups showed dramatic and statistically significant ODI reduction by 3 months postsurgery (p<0.001) and then maintained scores over time. ODI improvement was mean 26 points for groups 1, 2 and 3, while group 4 (2L/PS) had mean 24 points ODI improvement. Although patients with prior surgery took longer to reach final VAS pain levels (6 vs 3 months), there was no statistical difference between groups in pain reduction at 24 months. Although not statistically significant, the group with highest average preoperative VAS pain (group 2) had the greatest reduction in pain. Improvement of ODI and VAS pain is documented in all study groups. Of the 1,187 patients, 49 (4.12%) required new or revision surgery. Revisions were classified into four groups: posterior release/laminectomy at same level; TDA revision; scar/hematoma; and adjacent level surgery (ALS). Rates were too low in all groups to compare them statistically. Total TDA revision and ALS rates over 7-21 years were very low: 0.67% and 1.85%, respectively. <h3>Conclusions</h3> In one of the largest groups of TDA patients evaluated, this study demonstrates the robust long-term clinical success of one- and two-level lumbar TDA, as assessed at 7-21 years postoperatively. Patients had significant and maintained reduction in disability and pain scores over time, and low rates of index revision/reoperation or ALS, when compared to long-term published fusion data. Also, both 1- and 2-level lumbar TDA patients improved and patients with prior surgery at the index level had outcomes equivalent to patients with no prior surgery. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.