Three-year results from a randomized trial of lumbar discectomy with annulus fibrosus occlusion in patients at high risk for reherniation

Acta Neurochirurgica (2019) 161:1389–1396

A larger defect in the annulus fibrosus following lumbar discectomy is a well-known risk factor for reherniation. Procedures intended to prevent reherniation by sealing or occluding the annular defect warrant study in high-risk patients. This study sought to determine 3-year results of lumbar discectomy with a bone-anchored annular closure device (ACD) or lumbar discectomy only (controls) in patients at high risk for reherniation.

Methods This multicenter randomized trial enrolled patients with sciatica due to lumbar intervertebral disc herniation who failed conservative treatment. Patients with large annular defects after lumbar limited microdiscectomy were intraoperatively randomly assigned to receive ACD or control. Clinical and imaging follow-up was performed at routine intervals over 3 years. Main outcomes included rate of reherniations, reoperations, and endplate changes; leg and back pain scores on a visual analogue scale; Oswestry Disability Index (ODI); Physical Component Summary (PCS) and Mental Component Summary (MCS) scores from the SF-36; and adverse events adjudicated by a data safety monitoring board.

Results Among 554 randomized patients, the modified intent-to-treat population consisted of 272 patients in which ACD implantation was attempted and 278 receiving control; device implantation was not attempted in 4 patients assigned to ACD. Outcomes at 3 years favored ACD for symptomatic reherniation (14.8% vs. 29.5%; P < 0.001), reoperation (11.0% vs. 19.3%; P = 0.007), leg pain (21 vs. 30; P < 0.01), back pain (23 vs. 30; P = 0.01), ODI (18 vs. 23; P = 0.02), PCS (47 vs. 44; P < 0.01), and MCS (52 vs. 49; P < 0.01). The frequency of all-cause serious adverse events was comparable between groups (42.3% vs. 44.5%; P = 0.61).

Conclusions The addition of a bone-anchored ACD in patients with large annular defects following lumbar discectomy reduces the risk of reherniation and reoperation, and has a similar safety profile over 3-year follow-up compared with lumbar limited discectomy only.

 

Endplate changes after lumbar discectomy with and without implantation of an annular closure device

Acta Neurochirurgica (2018) 160:855–862

The implantation of a bone-anchored annular closure device (ACD) might be associated with the developed new endplate changes (EPC) after surgery.

Methods A post hoc analysis has been done in patients from a prospective randomized multicenter study. All patients underwent limited lumbar discectomy with intraoperative randomization into the groups limited lumbar discectomy alone or additional ACD implantation. Low-dose lumbar computed tomography (CT) and clinical investigations were performed preoperatively and 12 months after the operation.

Results A total of 554 patients were randomized. After exclusion of dropouts, the per-protocol population included 493 patients (251 in the control group and 242 in the ACD group); the follow-up rate was ≥ 90%. The number of patients showing EPC at baseline was similar in both groups. The number of patients showing EPC and the total EPC lesion area significantly increased in both groups over time, but significantly increased more in the EPC group for the superior and inferior endplate (all P < 0.0001). There was no association of pre-existing number and size of EPC with sex, age, or smoking habits. Correlation of clinical variables showed no relation with number, size, and increase of EPC area after surgery.

Conclusions Patients with primary lumbar disc herniation show EPC in the corresponding segments. There is a significant increase of lesion number and size within 12 months after discectomy. This increase is significantly more pronounced in the ACD group. Presence and growth of EPC is not correlated with low-back pain or ODI.