Closed-Suction versus Passive Surgical Drains: Design, Materials and Clinical Evidence — A Structured Narrative Review

Background. Surgical drains are placed after many operations to evacuate blood, serum, lymph or other fluid from wounds and body cavities. They are passive (gravity, siphon, capillary action) or active closed-suction systems driven by a bulb, spring or evacuated reservoir. Device-level choices are rarely discussed together with the clinical evidence. Methods. Four PubMed/MEDLINE searches were run through the NCBI E-utilities on 2 November 2026 (publication dates 1 January 1990 to 31 October 2026). Records were screened in two stages and outcomes were extracted as reported. Every reference was checked against PubMed and Crossref. No new meta-analysis was performed. Results. The searches returned 1056 records (918 unique); 94 reports were included (83 from the searches and 11 from other sources). Across specialties, meta-analyses found no consistent reduction in infection or haematoma with routine closed-suction drainage, whereas drains were associated with higher transfusion rates after hip and knee arthroplasty (risk ratio [RR] 1.43, 95% CI 1.19–1.72) and longer hospital stay after thyroid and axillary surgery (mean differences 0.88–1.52 days). Drains reduced seroma after axillary dissection (odds ratio [OR] 0.46, 0.23–0.91) and totally extraperitoneal hernia repair (OR 0.12, 0.05–0.29). Higher suction increased drained volume in randomised trials without a consistent clinical gain. Bench studies showed that reservoir negative pressure (−71 to −175 mmHg when empty) falls steeply as the reservoir fills and depends on how the bulb is compressed. Evidence on cross-sectional design and material is limited to small trials, laboratory studies and case reports. Conclusions. Routine drainage is not supported for most clean procedures; selective use is reasonable where seroma or large dead space is expected. When a drain is used, its function depends on lumen design, size, reservoir behaviour and timely removal as much as on the active/passive choice. Device-specific outcome data are scarce. Author affiliation: Suzhou Shenyun Medical Equipment Co., Ltd. — https://sybariatric.com . Conflict of interest: written by a manufacturer of surgical drainage products (commercial interest). No external funding.