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

Abstract

<h3>BACKGROUND CONTEXT</h3> 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. <h3>PURPOSE</h3> To examine the readmission rates of the randomized, prospective, multicenter trial at 4 years. <h3>METHODS</h3> 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. <h3>RESULTS</h3> 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 < 0.001, Fisher's exact test). HRs of age, gender, operative level, body mass index and current smoking status were calculated for each treatment arm. Notably, statistically significant readmission HRs for current smokers were 1.93 and 2.4 in control and ACD groups, respectively, whereas the HR for females in the control group was 1.97. <h3>CONCLUSIONS</h3> 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. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.