Two-layer inlay-onlay dural reconstruction technique for atrophic dura mater defects in the retrosigmoid approach

Atrophic and thinned dura mater (DM) encountered during the retrosigmoid approach poses a recognized technical challenge for achieving watertight dural closure. When direct suturing is not feasible, the risk of cerebrospinal fluid (CSF) leakage and related wound complications increases. In such cases, conventional duraplasty methods-including autologous grafts, sealants, and single-layer inlay or onlay techniques-may provide limited mechanical stability and insufficient resistance to CSF pressure, particularly in the setting of fragile, atrophic dura mater. These limitations highlight the need for reconstructive strategies that enhance both internal support and external sealing in selected clinical situations. To describe and assess the clinical feasibility and safety of a two-layer inlay-onlay dural reconstruction approach using the biomaterials G-Patch and Bloodstop for repairing dura mater defects in the retrosigmoid approach. Between January 2023 and November 2025, a total of 262 patients underwent posterior fossa surgery via the retrosigmoid approach at the Republican Specialized Scientific and Practical Medical Center of Neurosurgery (Tashkent, Uzbekistan). Among these cases, 19 patients (7.3%) were intraoperatively identified as having marked, non-suturable atrophy of the dura mater, which precluded watertight primary suturing. These 19 patients constituted the study cohort. The reconstruction strategy consisted of placement of an internal (inlay) G-Patch graft beneath the margins of the dural defect, secured with several interrupted 4 - 0 Prolene sutures. A hemostatic layer of Bloodstop was then applied, followed by placement of an external (onlay) G-Patch graft with sufficient overlap to reinforce the repair. Postoperative evaluation focused on wound healing, local wound conditions, and the occurrence of cerebrospinal fluid leakage or wound-related complications. Radiological assessment, when available, was used only to identify indirect signs of reconstruction failure or CSF-related complications. A stable two-layer dural reconstruction was achieved in all 19 patients. During the postoperative period, no cases of cerebrospinal fluid leakage, pseudomeningocele formation, or wound-related infectious complications were observed. None of the patients required reoperation related to dural repair. The postoperative course was uneventful in all cases, with no clinical signs suggestive of reconstruction failure or displacement of the reconstructive materials during the available follow-up. The proposed two-layer inlay-onlay dural reconstruction approach appears to be a feasible and safe reconstructive option for selected cases of non-suturable atrophic dura mater encountered during the retrosigmoid approach. The technique provides mechanical reinforcement through combined inlay support and onlay coverage and was associated with favorable short-term clinical outcomes in the present series. Given the preliminary nature of this experience and the limited cohort size, no definitive conclusions regarding superiority over other dural repair techniques can be drawn. Nevertheless, this approach may represent a useful addition to existing dural reconstruction strategies in carefully selected clinical situations.