Annular Repair Using an All-Suture Anchor Under Unilateral Biportal Endoscopy: Technical Note and Case Series

Large annular defects after lumbar discectomy remain a major risk factor for recurrent herniation, particularly when the annular tear is located adjacent to the bony endplate, for which no well-established endoscopic repair strategy is currently available. To evaluate the feasibility and early clinical outcomes of a novel endoscopic annular-repair technique using an all-suture anchor implanted into the superior surface of the inferior vertebral endplate, performed entirely through unilateral biportal endoscopy (UBE), for closure of large annular defects near the endplate after lumbar discectomy.

We present a novel annular repair technique performed entirely under UBE using an all-suture anchor implanted into the superior surface of the inferior vertebral endplate, which is particularly suitable for lumbar disc herniation (LDH) cases involving downward migration of disc fragments. A monofilament shuttle is advanced across the annular tear, enabling passage of high-strength sutures that approximate the torn annulus to bone. We developed a bone-to-annulus repair method in which a monofilament shuttle is passed across the annular tear under direct UBE visualization to deliver high-strength braided sutures through the defect; these sutures are then secured to an all-suture anchor placed in the endplate, tension-tested, and the knot buried within the annulus. The technique was applied in a preliminary consecutive series of five patients presenting with 5-6 mm full-thickness annular defects discovered intraoperatively during UBE discectomy. Procedural time, intraoperative complications, and early clinical and radiographic outcomes were recorded, follow-up included one-month clinical assessment and imaging.

The annular repair was technically feasible in all five cases, with the repair step adding a mean of 16 min to the standard discectomy. There were no intraoperative complications related to anchor placement or suture passage. All patients reported rapid relief of radicular symptoms and were mobilized early postoperatively. At one-month follow-up, clinical examination and imaging demonstrated intact annular repairs with no evidence of recurrent herniation or implant migration.

The described UBE all-suture anchor technique enables direct bone-to-annulus fixation and safe closure of moderate (5-6 mm) full-thickness annular defects through standard endoscopic portals. Early results indicate technical feasibility, safety, and promising short-term clinical outcomes. Further biomechanical validation and longer-term, larger-cohort studies are required to determine its effectiveness in reducing recurrent LDH.