HIRUDOTHERAPY IN RECONSTRUCTIVE SURGERY: CASE-REPORTS AND REVIEW

INTRODUCTION

Reconstructive surgical procedures are most often indicated in case of injuries resulting in a loss of tissues, severe burns, radical oncosurgical procedures and in the prevention of cicatricial contractures after secondary healing of wounds¹. In accordance with classic reconstructive diagram, the spectrum of reconstructive procedures includes skin grafts, local tissue transfers, distant flaps on vascular pedicles or flap surgeries using microsurgical techniques. Currently, the gold standard in head and neck reconstruction lies in free microvascular procedures, healing of which can be complicated by flap ischemia as a result of impairing the vascular pedicle before performance of a microanastomosis².

Restitution of blood supply is the primary requirement for proper healing of the flap to the surrounding tissues. Nevertheless, changes in tissue tension, or, on the other hand, compressions of the pedicle and the subsequent changes in blood supply can lead to a sluggish perfusion in all types of flaps. The main complication then lies in the arterial or venous insufficiency caused by the aforementioned vein compression or an arterial spasm. Despite the high success rate of free flaps – up to 7–10% of cases require a revision surgery due to endangered tissue viability³.

Timely diagnostics and intervention are the most important measures in a failing flap, and a surgical revision should be the method of first choice⁴. The success rate of the revision procedure is between 28% and 90% ^5,6. The success rate of a salvage surgery is higher in case of a flap failing on the basis of a venous thrombosis.

While a partial obstruction of the venous component can be physiologically compensated by an incipient neovascularization within 3–4 days⁷, total obstruction caused by a vessel wall collapse or a venous thrombosis lead to a significant involvement of microcirculation within 3 hours, and within 8–12 hours usually results in irreversible changes and in “no-reflow” phenomena in deep tissues, which in turn leads to a flap necrosis⁸. Even though a timely surgical revision is the most frequent solution of the complication, the physiological circulation is not always restored in all layers of the damaged tissue. A subcutaneous application of heparin or an application of a heparin-soaked gauze into the area of venostasis after a minor incision can represent an alternative conservative solution⁹. Hyperbaric oxygenation therapy (HBOT), which can have an excellent effect not only in case of venostasis, but also in case of tissue ischemia, can represent another option. A combination of hirudotherapy and hyperbaric oxygenation seems to be the ideal solution¹⁰. In accordance with our first experiences, hirudotherapy – a method using local application of medicinal leeches – can also be a useful solution of venous insufficiency.

OVERVIEW OF PROBLEMS OF HIRUDOTHERAPY: HISTORY AND CURRENT UTILIZATION OPTIONS

European medicinal leech (Hirudo medicinalis) is a representative of the phyllum Annelida, endemic in Southeast Asia and Europe and it is the most commonly used species in medicine¹¹. Leeches live in clean fresh water and they are poikilothermic animals, capable of surviving temperatures from 0–35°C. Their body can be up to 15 cm long and it has a sucker on each end (Figure 1). The top part of the body is brownish-green with pronounced red and brown stripes. The bottom part of the body is light with darker spots. The body of a European medicinal leech is composed of approximately 100 outer annuli, covered with a thin cuticle. This non-cellular protective layer is very flexible and pliable and it allows the leech to increase its volume several times after feeding¹². Its body muscles allow crossing rather large distances in water, breathing through body wall and also an attachment to a host. Leech’s head contains a small anterior sucker, which surrounds three chitin jaws located in a Y position, each of which is equipped with 100 tiny teeth (Figure 2, 3). The jaws can extend and thus penetrate skin or a mucous membrane. Subsequently, the jaws dilate rhythmically, thus creating vacuum effect. The body of a leech can absorb up to a tenfold of its original volume in single feeding and it can survive up to 2 years without the need to feed. Salivary glands in the laryngeal area produce an anticoagulant substance (hirudin). Therefore, a bite of a leech is accompanied by a prolonged bleeding from the wound, which can bleed for up to 12 hours^13,14. The leech uses highly sensitive receptors located near the upper lip to find the right spot to attach. If it registers blood, glucose, sweat or pulsation with tissue temperature between 35–40°C, the leech will attach¹⁵. The rear sucker only serves for stabilization of the leech’s position during blood sucking.

On the basis of experiences of large reconstructive centers (France, Germany, USA) using hirudotherapy^16,17,18, it is recommended to keep leeches for medicinal purposes in a sterile glass container with small perforations on the lid with a sufficient amount of non-saturated mineral or sterile water with an addition of hirudin salts, diluted in the concentration of 2g per 4.5 L. This enables to keep up to 50 leeches in 2.5 L of water at a temperature of 5–8°C for several weeks or even months. Replacement of the medium should be performed every week with minimum exposure to daylight. Manipulation should be done using wide anatomic forceps. It is recommended to provide patients with an antibiotic protection against Aeromonas hydrophila, a symbiotic gram-negative bacteria occurring in leeches’ digestive tract, which is of significant importance for their growth. However, at the same time, it is a pathogen, which can cause muscle necrosis or formation of an abscess or cellulitis with possible development of sepsis. According to the available literature, the risk of manifestation of this complication is 7-20%; and that is why it is necessary to prevent it by administering Ciprofloxacin/Gentamicin for the period of hirudotherapy, but maximally for 5 days¹⁹. The actual application of a leech is performed with a 5 ml syringe to the affected location (Figure 4), which is delimited with a perforated sterile cloth to prevent unwanted migration of the leech. Its head can be identified by its fast, “searching” movements (Figure 5). If the leech does not attach on the desired location, the surface of the location can either be broken with a syringe, or a small incision can be made. After the leech attaches to a location, and when it is clear that it is starting to suck blood, the leech does not change its position any more. After the end of feeding, which usually takes from 15 to 45 minutes, the leech detaches from the tissue and it starts to move using peristaltic movements²⁰. However, if the congestion area does not provide even minimum amount of blood, the leech can change its position or even move to a different body part⁵. Because of the possibility of its movement, careful monitoring of the leech’s position is important, especially for example near a tracheostomy cannula¹⁷. Some authors recommend wrapping the body of the leech with a silk stitch and securing its ends with a clamp. A response to an adequate hirudotherapy will manifest itself with a visible improvement of perfusion in the order of minutes. After use, the leech has to be killed by an insertion into a 70% ethanol solution for 5 minutes and subsequently disposed of as a biological waste^16,18.

One of the first documented records on the use of leeches in medicine was found in an Ancient Egyptian tomb from 1567–1308 B.C. ²¹. The first written record of medicinal use of leeches is attributed to Nicander of Colophon (200–130 B.C.) in his medical poem Alexipharmaca²². Therapeutic use of leeches was widespread in the Ancient Greece, China, India and pre-Columbian America. These procedures are very well documented in works by Pliny the Elder, Gales or Avicenna²³. In the Middle-Ages, leeches were used by barber-surgeons. Probably the largest use of leeches in Europe occurred during the Napoleonic wars in France thanks to a military surgeon François-Joseph-Victor Broussais (1772–1832), who is being referred to as “the bloodiest doctor of all times”, because he applied hirudotherapy to all patients regardless of their problems. However, in this period, leeches have also been used rationally by one of the founders of maxillofacial surgery, Dieffenbach (1792–1847), in 17 cases of plastic and reconstructive surgeries of the face²⁵. Year 1884 was a milestone in the history of hirudotherapy, because Haycraft has proven that the throat and the mouth of leeches contain a substance with an anticoagulant effect. This compound was later isolated, denoted “hirudin” by Jacob and used in a blood transfusion in 1915 ²⁶. Use of leeches in modern reconstructive surgery is dated back to 1960, when they were used by Slovenian plastic surgeons Derganc and Zdravic to restore flap microcirculation ²⁷. The same success was registered by Henderson in case of a scalp replantation in 1983 and by Upton after an avulsion of the auricle in a five-year-old boy in 1985 ²⁸. Since 2004, on the basis of an FDA decision, hirudotherapy has been recognized as an official treatment of complications in plastic and reconstructive surgery²⁹. Among others, hirudotherapy is being used in the treatment of diseases affecting vessels, such as thromboembolia, limb varices³⁰, hemorrhoids³¹, but also arthritis, tendinitis, hypertension diseases or in evacuation of voluminous soft tissue hematomas. Its role in reconstructive surgery is completely unique and unsubstitutable, because it can contribute significantly to saving pedicled or free flaps^32,33,34. Despite the benefits of hirudotherapy, no unambiguous recommended indications are available regarding its use in replantation of fingers³⁵, auricles³⁶, lips³⁷, nose³⁸, penis³⁹ or other organs.

The effect of active substances from the salivary glands of leeches persists for 6–8 hours (Table 1), then the leeches can be replaced⁴⁰. Under in vitro conditions, leeches are able to affect coagulation in up to 100 ml of blood⁴¹, but there is no unified opinion regarding the amount that should be used in patients with free or pedicled flaps. You have to take into consideration the composition and volume of tissues, the condition and characteristics of the recipient location, degree of congestion and the time from the surgery. Literary resources contain significant differences in protocols of individual sites (for similar situations, the available literature states usage of less than 10 up to 350 leeches per flap.^34,42).

In a study performed by Nguyen et al.⁴³, the authors have described larger usage of leeches in a partially affected flap than in a completely affected flap. This difference can be explained with a different degree of venous insufficiency at the beginning. In cases of a distal insufficiency of the flap, an application of one to two leeches per every cycle in dependence on the flap size is generally recommended. If a severe congestion of the entire flap is present, then one leech can effectively improve microcirculation approximately in the area of 10 cm2 of tissue. Nevertheless, it seems logical to adjust the number of leeches based on flap thickness. More specifically, twice the number of leeches per every additional 2 cm of thickness is rational and supported by numerous studies^43,44,45.

Blood losses in the course of hirudotherapy are constant. On average, a medicinal leech will actively draw about 2.5 ml 
of blood in 20–70 minutes. The period of bleeding after the bite is described to last from 1.5 to 4 hours, up to 90 % of passive bleeding occurs within 5 hours after detachment of the leech, when the average blood loss cannot be estimated⁴⁸. Patient’s blood count should be known before to the surgery and monitoring of its possible drop after surgery each 24–48 hours in accordance with the number of leeches used is a matter of course. A general assumption is that in case of an application of 1 leech every 2 hours, the hemoglobin will drop by 10 g/L in 24 h.

Complications of hirudotherapy are rarely mentioned in the available literature. Whitaker et al.⁴² calculated their frequency to 21.8%. Half of the complications are attributed to infection caused by the microbial flora inhabiting the digestive tract of leeches (Aeromonas hydrophila, Aeromonas, Serrata, Vibrio). The above-mentioned complication is described in 14% of cases in the metaanalysis performed by Whitaker et al.⁴². The infection manifested itself as lymphangitis, necrotizing fasciitis with formation of abscesses or even sepsis⁴⁷. The infection can manifest itself from within 24 hours after leech application up to 4 weeks since treatment initiation⁴⁸. Infectious complications significantly decrease the survival rate of the flap (from 88% to 37%, resp. 30% ⁴²). That is why a prophylactic administration of antibiotics is recommended by most authors, and it should be terminated no earlier than 24 hours after completion of hirudotherapy⁴⁹. Cephalosporins of 2^nd and 3^rd generation are recommended most often⁴¹.

Venous insufficiency develops most often during the first several hours after surgery as a continuously worsening of blood congestion. In flaps with skin islands, accelerated capillary refill time (less than 2s) is visible and in the following couple of hours, dark pink color of the skin transforms to pinkish-purple color. Very often, small spots (“mottled skin”) start to appear on tissue surface, and flap margins will spontaneously start bleeding dark red blood.

In local flaps with random vascularization, distal venous insufficiency occurs quite often and it is usually very difficult to resolve with surgical procedures. Before we decide to apply leeches, we should decrease tension of the flap in several places by removing stitches, and, after the symptoms disappear, we should perform a resuture.

In case of pedicled flaps, venous congestion can be predicted already during the procedure or in a short period of time after harvesting⁵⁰. It appears within several hours after the surgery as a distally delimited purple area. If you cannot perform a surgical correction of this condition, you have to initiate hirudotherapy as soon as possible³³ (Figure 6). However, if the congestion affects the entire flap, it is possible that the pedicle twisted. In such case, revision surgery is the method of choice. It consists of a decompression of the pedicle and a fixation of the flap in a different location or from its reversal into the place of harvest. After 48 hours, the flap can once again be moved into the desired position. This procedure should always be considered in large or voluminous flaps, in which the benefit of hirudotherapy is limited.

Apart from replantation of fingers or small organs such as parts of auricles, leeches cannot replace venous microanastomosis⁴³. The use of leeches is more suitable in cases of repeated failures of the microsurgery for local or general causes. In free skin flaps or perforator flaps, you can use leeches in case of a distal perfusion insufficiency, which develops later than in more voluminous flaps. Hirudotherapy should be initiated as soon as possible (Figure 7). Leeches are to be applied on the affected area in higher numbers than in case of pedicled flaps. Hirudotherapy can be initiated at any time during the period between the discovery of congestion and the beginning of the surgical procedure. A prevention of spreading of thrombus is the clear advantage of this approach⁵¹.

Contraindications of hirudotherapy include immunosuppression, severe arterial insufficiency, hemophilia or hemocoagulation disorders, sepsis, hepatic insufficiency, cachexia, religious reasons, or possibly mental disorders⁵².

CASE REPORTS

In our department, we used hirudotherapy in three patients in 2019. These were two women (65 and 67 years old) and a man (41 years old). All patients have undergone surgery because of an oncological indication, the first case concerned a pedicled submental flap for a defect replacement after a resection of a tongue edge, in the second patient, a free forearm flap was used to reconstruct the inner side of a cheek. The last case concerned a replacement of a defect on the left side after a subtotal maxillectomy with an osteomyocutaneous free fibular flap.

Case Report 1

Male, 41 years old, minor hepatopathy caused by toxonutritive etiology, otherwise without other monitored internal disorders. Resection of the right edge and apex of the tongue was performed because of a moderately differentiated (G 2-3) squamous cell carcinoma (pT2, pN0, MX) with an elective neck dissection: IA, IB, IIA, IIB, III, IV, VA on the right; IB, IIA on the left. The defect was subsequently reconstructed with a submental flap on a left-sided pedicle. The patient only received low-molecular weight heparin 0.4 ml s.c. within thromboembolic disorder prevention. Within 12 hours after the surgery, venostasis developed centrally and the flap swelled up. In the course of a wound revision, we have performed hematoma evacuation, enlargement of the channel for vascular pedicle and a subsequent application of two leeches, which were later applied according to the patient’s response in the amount of 1-2 every 8 hours. Over the total period of 4 days, patient’s overall condition improved gradually, a total of 10 leeches was applied and no blood transfusion was needed. In this case, the flap healed fully to the tongue tissue and an adequate function of the flap was secured.

Case Report 2

Female, 65 years old, non-smoker. Patient’s medical history includes hypertension, atrial fibrillation and ischemic heart disease. The patient has undergone a resection of the right cheek because of a moderately differentiated squamous cell carcinoma (G2) and an elective neck surgery reg. IA, IB, IIA, III. (pT2, N1, MX). Using the Dieffenbach-Weber approach, the defect was reconstructed with a free radial forearm flap. Symptoms of bleeding under the flap started to manifest after 72 hours in the form of an increased tension/swelling and a change in color of the flap. The patient received 5,000 international units (IU) of heparin per day continuously. After a subsequent surgical revision and hematoma evacuation without the need for an intervention in the area of microanastomosis, we applied 2 leeches every 8 hours; after 2 days, this frequency was changed to 1 leech every 8 hours because of an improvement in the flap color. Hirudotherapy was performed for a total of 5 days; a total of 18 leeches were used and two blood transfusions had to be administered. There were no other subsequent complications and the flap healed to the base and the surrounding tissue without any loss.

Case Report 3

Female, 67 years old, non-smoker. The patient is followed by her general practitioner for hypertension, bronchial asthma and hepatopathy caused by medication. In 2017, this patient has undergone a subtotal maxillectomy on the left side because of a plexiform sarcoma with a block neck dissection reg. IA, IB, IIA, IIB, III. (pT4a, pN0, pMX). Subsequently, the patient has undergone a dose of radiotherapy of 66 Gy. Two years later, we performed a reconstructive procedure – a replacement of the maxilla using 3D planning and an individually manufactured splint with an osteomyocutanneous free fibula flap. The patient was administered heparin in the amount of 10,000 IU/24 hrs and Fraxiparine 0,3ml s.c. per 12 hours. Mottled skin occurred on the flap 48 hours after the procedure and venostatic changes appeared on the skin island of the flap, and that is why we immediately performed a revision surgery of the microanastomosis and confirmed an extensive thrombosis of the venous component. Venous grafts have been harvested and reattached in order to improve venous drainage. As a supportive therapy, we have subsequently used 2 leeches applied on the center of the skin island every 6 hours, but despite a 24-hour improvement, the flap necrotized gradually and it had to be removed on the 3^rd day after the revision surgery. A total of 16 leeches and four blood transfusions have been administered.

All the patients were secured with heparin after the surgery. We kept their hemoglobin level above 90 g/L. Despite these measures, tissues manifested typical symptoms of venostasis already several hours to days after the procedure. We have started the initial treatment after surgery by loosening the stitches around the edges of the flap, by an evacuation of hematomas and an introduction of capillary drainage on the base of the post-operative defect. If these measures failed to improve the perfusion of the tissues, we proceeded with surgical revision, i.e. loosening of the entire flap and an examination of the pedicle. In two cases, the color and texture of the tissues improved. We have promptly responded to the persisting symptoms of congestion by applying 1–2 leeches every 8 hours for the period of 4–5 days. In the first two cases (forearm and submental flap), which represented a combination of hirudotherapy and a surgical treatment, the flaps healed completely to the surrounding tissues.

In the last case (free fibula flap), surgically satisfactory result has not been achieved despite more than a 6-hour long revision surgery of the venous anastomosis. With regards to the initiation of hirudotherapy, the antibiotic therapy has always included a combination of broad-spectrum penicillins/lincosamides with gentaminicin⁵³. Blood transfusions were necessary in both patients treated with free flaps.

DISCUSSION

Therapeutic use of leeches is a method that has been known since the times of Ancient Egypt²⁶. A certain renaissance of this method currently takes place especially in the field of reconstructive surgery^13,14. Medicinal leeches can be used very well to save venostatic tissues after a replantation of fingers, scalp, auricles, lips and parts of the nose until angiogenesis takes place and the conditions of venous drainage improve^15,38,54,55. In specialized literature, there are number of studies confirming the success rate of hirudotherapy in free and pedicled flaps^{15,54,55,56,57,58}.

The simplest option with a high success rate of diagnostic recognition of a “failing flap” is a clinical observation of its color and temperature, capillary refill, turgor, monitoring of temporal latency of the discharge and blood color after a puncture with a needle, or monitoring with a Doppler flowmetry⁵.

Kubo et al.⁵⁹ evaluated the surgical revision of a flap with an affected venous component as a first-choice method with the highest success rate. At the same time, he believes that non-surgical methods should be used if the revision surgery cannot be performed or if it fails repeatedly. Vascular endothelial growth factor (VGRF) in combination with blood drawing using leeches and a hyperbaric oxygenation can reportedly increase the flap survival chances. Nevertheless, controlled clinical studies performed on larger sets of patients are still missing and therefore, standardized indications of therapy of post-surgery venostasis remain limited. Apart from the replantation of fingers or small organs such as parts of auricles, leeches definitely cannot replace venous microanastomosis⁴³. Foucher at al.⁶⁰ determined that in necrotic flaps, the attachment of leeches did not take place in all cases, which could be a good test to determine tissue quality. Delayed attachment of a leech to tissue together with small amount of blood drawn is considered a negative prognostic factor of flap viability despite its favorable color⁸. Several experimental studies have confirmed an improved perfusion after leech application in comparison to other, alternative methods^17,18.

The number of applied leeches varies significantly from one per day⁵⁴ up to several in the course of each hour⁵⁹, which points out the absence of a therapeutic scheme we could follow. The replacement interval is not unequivocally recommended as well. A study on brown rats has shown both the inefficiency of the use of large numbers of leeches and the lack of a positive effect on flap survival⁴⁹. It is important to note that tissues should be carefully clinically examined prior to the leech application and they should not be used, if they show signs of a mixed arterial venous disease⁶¹.

In hirudotherapy, blood losses cannot be predicted reliably. Whitaker et al.⁴² described the need for transfusion in 50% of cases. The more voluminous flap and more advanced venostasis, the more aggressive hirudotherapy should be. Because of this, the hemoglobin level may drop faster, which will in turn worsen the alteration of the affected tissues even more⁴¹. Blood loss is the most visible and also the most important effect of hirudotherapy, but the effects of the discharge from salivary glands of the leeches are much more complex; they influence vasodilatation and they have anesthetic and anti-inflammatory properties^13,26.

In the available literature, the percentage of inflammatory complications associated with hirudotherapy is between 4% and 20% ^19,52,56. Aeromonas hydrophila was reported to be the most frequent cause of this complication ⁴⁷, it constitutes 9% of all infections. Recent clinical studies confirm a higher frequency of infectious complications in patients, who were not administered the antibiotics prophylactically⁵². Recently, evidence of a resistance of the aforementioned pathogen to first generation cephalosporines, penicilines and tetracycline is being reported. In comparison, fluoroquinolones seem to be consistently able to deal with the infection³².

CONCLUSION

Hirudotherapy can successfully be used in patients in cases where venostasis occurs in free or pedicled flaps and a surgical revision is either impossible or it cannot provide adequate restoration of circulation. Despite ambiguous recommendations in the available literature, it is possible to consider procedures concerning indications, dosage, application frequency and the adequate antibiotic treatment. The clinical and the instrumental monitoring and the related adjustments of leech dosage all play a fundamental role in the success of hirudotherapy. The anticoagulant and decongestive effect of this method in treatment of distal perfusion insufficiency in local or pedicled flaps is very well known, but this article also points out the options of a successful use of this treatment method in free or pedicled flaps in the intraoral location as well.

Disclosure: This manuscript has not been published and is not under consideration for publication elsewhere. We have no conflicts of interest to disclose. We declare that this study has received no financial support. All procedures performed in this study involving human participants were in accordance with ethical standards of the institutional and/or national research committee and with the Helsinki declaration and its later amendments or comparable ethical standards.

The author of all photographs: Petr Heinz.

Corresponding author:

Assoc. Prof. Richard Pink, MD, DMD, PhD

Department of Oral and Maxillofacial Surgery,

Faculty of Medicine and Dentistry,

Palacký University Olomouc and University Hospital Olomouc

I.P Pavlova 6

779 00 Olomouc

Czech Republic

E-mail: richard.pink@fnol.cz