American Society of Hirudotherapy

Microsurgical Replantation (Digit / Ear / Scalp)

FDA-cleared application: post-replantation venous decompression in digits, ears, scalp, and partial avulsion injuries.

Tier A — FDA-cleared indicationFDA-cleared device indicationLast updated: 2026-05-26 · Reviewed by ASH Editorial Board

Patient Summary

Is this FDA-cleared for this use?
Yes — FDA-cleared under K040187 (June 21, 2004) for medicinal leech application to relieve venous congestion in microsurgical reconstructive procedures, including replantation.
What evidence exists?
This is an FDA-cleared use of medicinal leeches. Published hospital studies of fingertip, ear, and scalp replantations report 70 to 80 percent survival of the reattached tissue when leech therapy is started promptly. Ear replantation results have been particularly encouraging in the published series. Without leech support, many of these tiny-vessel reattachments would fail because conventional vein surgery is not possible at that small a scale.
Main risks
  • Bleeding from each bite site for 6 to 10 hours after the leech detaches
  • Need for blood transfusion (roughly 1 in 4 to 1 in 3 patients) because of cumulative blood loss
  • Aeromonas hydrophila infection from leech gut bacteria (your team starts ciprofloxacin or another antibiotic before the first leech)
  • The reattached tissue may still fail despite leech therapy if artery flow cannot be maintained
  • Allergic reaction to leech saliva (uncommon)
  • Permanent bite-mark scarring on the reattached tissue
Who should not consider this
  • Patients on warfarin, apixaban, rivaroxaban, dabigatran, or heparin
  • Patients with hemophilia or another inherited bleeding disorder
  • Patients with severe anemia (hemoglobin under 10 g/dL) before therapy
  • Patients with an active bloodstream infection or sepsis
  • Patients allergic to ciprofloxacin or unable to take any antibiotic that covers Aeromonas
  • Patients whose reattachment has failed arterial inflow — that needs surgical revision, not leeches
What to ask your clinician
  • Is the problem with my reattached part a vein problem? Leeches only help with that, not artery problems.
  • Which antibiotic will I receive to prevent Aeromonas infection, and for how long?
  • How often will my hemoglobin be checked, and at what level would you transfuse?
  • Roughly how many days of leech therapy do you expect before the tissue can drain on its own?
  • What does my family need to know about wound care and watching for problems?
  • If the replant fails despite leeches, what are the next options for me?
  • Can I refuse blood products on religious or personal grounds, and what would that mean for my care?
When to seek urgent care
  • Bleeding from a bite site soaking through more than one gauze pad per hour, or continuing more than 24 hours after the leech detaches
  • Increasing redness, swelling, warmth, or pus around the bite area or the reattached part
  • Fever above 38.0 C / 100.4 F, chills, or feeling generally unwell
  • Reattached finger, ear, or scalp turning darker, colder, or harder despite ongoing therapy
  • Hives, throat tightness, facial swelling, or trouble breathing

What this does NOT mean

  • It does not mean the reattached body part is guaranteed to survive — even with leech support, around 20 to 30 percent of these severe injuries are still lost.
  • It does not mean leeches replace surgery — the surgeons must successfully reconnect at least the artery; leeches only help with the vein side of the problem.
  • It does not mean home use of leeches is safe — this is an inpatient therapy with continuous blood-count monitoring and antibiotic coverage.
  • It does not mean all leeches are interchangeable — only FDA-cleared, lab-raised Hirudo verbana from 510(k)-cleared suppliers is appropriate; each leech is used once and then incinerated as biohazard waste.

Safety cross-references

Clinical Profile

Category
surgical reconstruction
ICD-10
S68.011A, S68.111A, S68.711A, S08.812A, S08.119A
Safety tier
high

Evidence Summary

Distal digit and ear replantations frequently lack viable venous outflow due to vessel caliber (<0.5mm) or crush injury to the venous system. Leech therapy provides temporary venous drainage during the 5-10 day window of neovascular ingrowth. Salvage rates of 70-80% are reported in series of fingertip replantations where conventional venous anastomosis was not feasible. Ear replantation outcomes are particularly favorable: Concannon and Puckett (1998) reported a successful pediatric ear replant performed without any venous anastomosis, decompressed with medicinal leeches, and their literature review documented venous congestion requiring external decompression in about 57% of ear replants and an overall salvage rate near 80%. Scalp replantation following avulsion (typically machinery or motor vehicle trauma) is another well-documented indication.

Treatment specifics

How many leeches, where they are placed, how long a session lasts, and whether to repeat are clinical decisions made by a qualified provider under institutional protocol — not something to self-administer. Discuss the specifics with a clinician experienced in medicinal leech therapy. (Clinicians: switch the audience selector in the top bar to “Clinician” to view protocol detail.)

Key Trials

  1. Concannon MJ et al. (1998), n=1 · PMID 9811007 · ASH analysis →
  2. Foucher G et al. (2003), n=39
  3. Mortenson BW et al. (1998), n=16
Sample sizes of key trials for Microsurgical Replantation (Digit / Ear / Scalp)Concannon MJ et al. 19981Foucher G et al. 200339Mortenson BW et al. 199816
Participants per key trial (n). Larger trials generally carry more statistical weight; case series with unspecified counts are omitted.
Study-design composition of the evidence base for Microsurgical Replantation (Digit / Ear / Scalp)3studies
  • Case Report: 1 (33%)
  • Case Series: 2 (67%)
Composition of the cited evidence base by study design, from strongest (meta-analysis, systematic review) to weakest (case report). A base weighted toward RCTs and reviews is more reliable.

Detailed Trial Entries

12 trials indexed in the ASH RCT Library with full Study Profile, GRADE rating, and clinical implications:

Contraindications

  • Active anticoagulant therapy (warfarin INR >2.0, DOACs, heparin)
  • Hemophilia or other bleeding disorder
  • Severe anemia (Hb <10 g/dL)
  • Active bacteremia or sepsis
  • Known hypersensitivity to leech salivary proteins
  • Pregnancy (relative — first/third trimester)
  • Immunocompromised state with severe neutropenia
  • Failure of arterial inflow (replantation is non-salvageable without arterial reconstruction)
  • Inability to administer ciprofloxacin or alternative anti-Aeromonas prophylaxis

Related Conditions

Venous Congestion in Surgical Flaps

FDA-cleared application: medicinal leech therapy to relieve venous congestion in compromised tissue flaps awaiting vascular ingrowth.

Breast Reconstruction Flap Salvage

FDA-cleared application: venous decompression of compromised DIEP, TRAM, and latissimus dorsi flaps in post-mastectomy reconstruction.

Explore the evidence base

This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.

Microsurgical Replantation (Digit / Ear / Scalp) — Hirudotherapy Evidence | ASH