Association between adjunctive use of an absorbable polymer tissue sealing membrane and postoperative subcutaneous fluid collection after posterior fossa surgery

Postoperative subcutaneous fluid collection is an important wound-related complication after posterior fossa surgery and may delay recovery, necessitate additional interventions, and prolong hospitalization. Strategies that improve dural closure integrity may reduce postoperative fluid accumulation. This retrospective cohort study included 237 adult patients who underwent posterior fossa craniotomy at Sun Yat-sen Memorial Hospital, Sun Yat-Sen University, between January 2023 and January 2025. Patients were classified according to the dural closure technique used in routine clinical practice: conventional dural suturing plus an absorbable polymer tissue sealing membrane (n = 80) or conventional dural suturing alone (n = 157). Membrane use was not randomized, and a standardized indication for its use was not documented in the retrospective dataset. The primary outcome was a clinically diagnosed postoperative subcutaneous fluid collection within 3 months after surgery. No uniform biochemical or imaging criterion was prespecified to establish the cerebrospinal fluid (CSF) origin of every collection; therefore, the endpoint was not defined as confirmed CSF leakage or pseudomeningocele. Secondary outcomes included hospitalization duration, total surgical costs, and epithelialization time. Logistic regression was performed to identify factors associated with postoperative subcutaneous fluid collection. Postoperative subcutaneous fluid collection occurred in 6 of 80 patients (7.5%) in the observation group and 29 of 157 patients (18.5%) in the control group ( P  = .024). The observation group had a shorter postoperative hospital stay than the control group (8.2 ± 2.1 vs 10.5 ± 3.4 days, P  = .012). No significant between-group differences were observed in total surgical costs or epithelialization time. Multivariable logistic regression showed that use of the sealing membrane was associated with lower odds of postoperative subcutaneous fluid collection, whereas older age and paramedian incision were associated with higher odds. Adjunctive use of an absorbable polymer tissue sealing membrane during dural closure was associated with a lower incidence of postoperative subcutaneous fluid collection and a shorter hospital stay after posterior fossa surgery, without a significant increase in surgical costs. Because treatment allocation was non-randomized and the fluid collections were not uniformly confirmed as CSF by a standardized biochemical or imaging criterion, these findings should be interpreted as an association and require prospective validation.