Suturing strategies for annular defects following lumbar discectomy: a structured narrative review and a hypothesis-generating functional assessment framework

Abstract

Residual annular defects after lumbar discectomy may contribute to recurrent disc herniation, and several repair strategies—including direct annulus-to-annulus suturing, bone-anchored repair, and soft-tissue augmentation—have been described. However, evidence directly comparing suture configurations or linking specific defect characteristics to particular repair constructs remains limited. This structured narrative review summarizes current annulus fibrosus suturing techniques and examines a hypothesis-generating framework for describing annular defects according to intraoperative apposability and anchorage conditions. A structured search of major English- and Chinese-language databases was performed to identify clinical, technical, and biomechanical studies of annular defect repair after lumbar discectomy; the final search was conducted on April 2, 2026. The literature describes I-shaped, II-shaped, V-shaped, and X-shaped annulus-to-annulus sutures, bone-anchored techniques, and posterior longitudinal ligament augmentation. Most clinical evidence comes from retrospective or small observational studies, while direct head-to-head comparisons and configuration-specific biomechanical data remain scarce. On the basis of three sequential intraoperative assessments—defect apposability, adequacy of tissue purchase, and provisional apposition behavior—we propose four provisional defect phenotypes: provisionally stable opposable, provisionally unstable opposable, anchorage-deficient, and non-opposable. These phenotypes are intended to provide a structured vocabulary for intraoperative description rather than validated treatment assignments. Proposed relationships between defect phenotypes and repair constructs should be regarded as testable technical hypotheses rather than validated treatment recommendations. Current evidence supports the technical feasibility of several annular repair strategies but is insufficient to establish either the superiority of specific suture configurations or a validated defect-based treatment algorithm. Standardized operational definitions, interobserver reliability testing, comparative biomechanical studies, and prospective clinical validation are required before the proposed framework can be used to guide clinical decision-making.