In reconstructive and microsurgery, the leech is a salvage tool — a way to hold compromised tissue alive while the body re-establishes its own venous drainage.
Free flaps, replanted digits and composite grafts all depend on a delicate balance between arterial inflow and venous outflow. Arterial problems usually announce themselves quickly and are addressed surgically; venous congestion is more insidious and is exactly where leech therapy has the strongest track record.
The salvage window
Applied early, leeches can decompress a congested flap repeatedly over several days, often long enough for neovascular venous outflow to mature. The decision to start, and when to stop, is a clinical judgement made by the operating team against the appearance and behaviour of the tissue.
Practical considerations
- Reliable attachment matters — fasted, medical-grade animals
- Grading to the site: fine grades for digits, larger for bulky flaps
- Antibiotic prophylaxis against Aeromonas is standard practice
- Single-use per patient; never reuse a leech between patients