26. Occluding annular defects with a bone anchored closure device results in fewer procedure related readmissions after lumbar discectomy: Four-year data from a multicenter, prospective, randomized superiority study

BACKGROUND CONTEXT Lumbar discectomy is typically successful in reducing pain and neurological dysfunction when conservative treatment fails; however, approximately 30% of patients experience readmissions from device- or procedure-related serious adverse events. Large defects (≥ 6 mm wide) in the annulus fibrosis are a significant risk factor for readmission. Early results with occluding such defects with an annular closure device (ACD) have been promising in reducing readmission rates, but long-term outcomes have not been reported. PURPOSE To examine the readmission rates of the randomized, prospective, multicenter trial at 4 years. METHODS Primary discectomy patients at 21 sites were randomized intraoperatively 1:1 for treatment with discectomy alone (control, 278 patients) or discectomy followed by the ACD (272 patients). Inclusion criteria included 6 weeks conservative care, minimum Oswestry Disability Index (ODI) and visual analog scale (VAS) for leg pain scores (40/100), 5 mm minimum posterior disc height, and an intraoperatively measured annular defect width of 6-10 mm. Readmissions were identified as device- or procedure-related SAEs, as adjudicated by 4 clinicians. Survival analysis and univariate Cox regression using all participants were used to calculate readmission rates and hazard ratios (HRs) of demographic factors, respectively. RESULTS A total of 463 of 550 subjects (84.2%) was assessed at 4 years: 229 of 278 (82.4%) control and 234 of 272 (86.0%) ACD. The overall readmission rates for the control and ACD groups were 19.8% and 12.2%, respectively (p = 0.0099, log-rank test). ACD deficiency was observed in 11 subjects (4.0%). Reherniation at the index level occurred in 46 (16.5%) control and 18 (6.6%) ACD participants (p CONCLUSIONS Occluding annular defects ≥ 6 mm by augmenting lumbar discectomy with an ACD reduced readmission by 38.4% at 4 years, primarily due to a reduction in reherniation at the index level. Female gender and smoking were risk factors for readmission. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.