Abstract
Objective
The objective of the study was to determine the utility of leech therapy in venous congested microvascular free flaps in which venous outflow could not be established or surgical revision was unsuccessful.
Methods
We conducted a retrospective review of all patients at a tertiary referral center from January 2002 to December 2008 who received leech therapy for a venous congested microvascular free flap in which venous outflow could not be established primarily or failed surgical revision.
Results
Six patients were identified. Leech therapy was required for a median of 9 days (4-14 days). The median lowest hemoglobin level per patient was 8.0 g/dL (5.4-9.3 g/dL). All patients (6/6, 100%) required blood transfusions during therapy. The median number of units of packed red blood cells transfused per patient was 13.5 U (4-29 U). All flaps (6/6, 100%) were successfully salvaged with leech therapy. There was one minor complication, observed as 2 episodes of syncope in the same patient, related to anemia. There were no cases of infection transmitted as a result of leech therapy.
Conclusions
Leech therapy can be used to successfully salvage venous congested microvascular free flaps in the absence of primary venous outflow. Leech therapy can be used safely and with little morbidity compared with other reports.
1
Introduction
The use of microvascular techniques allows for reconstruction of extensive defects of the head and neck that result from tumor resection, congenital deformities, and trauma. The success of microvascular free flaps has been reported to be as high as 95% to 98% ; however, these flaps continue to fail for a variety of reasons including arterial insufficiency, technical errors during harvest or inset, infection, and patient comorbidities, among others. The most frequently cited reason for failure of microvascular free flaps is compromise of venous outflow. Hidalgo and Jones reviewed 150 consecutive microvascular free flaps and reported 11 cases of circulatory compromise, 8 of which were attributed to venous compromise. All 8 of the flaps showing evidence of venous compromise were salvaged with reexploration and revision of the anastomosis or thrombectomy.
Surgical exploration and revision of the venous anastomosis serve as the criterion standard for attempts at flap salvage secondary to venous compromise. In some cases, surgical exploration and revision are attempted and fail because of distal/multiple venous thromboses, whereas in other cases, surgical revision is not an option because of patient stability or the lack of a venous anastomosis to revise (ie, cases of traumatic avulsion). Nonsurgical options must be used in an effort to salvage these flaps. Nonsurgical options include bloodletting via stab incisions following injection of heparin , hyperbaric oxygen therapy , thrombolytics , mechanical leeching , and the use of the medicinal leech .
The medicinal leech ( Hirudo medicinalis ) is commonly used as a bridge to surgical revision of a compromised free flap, with studies showing significant improvement of perfusion of venous congested flaps following the application of medicinal leeches . Less commonly, medicinal leeches are used as a total replacement for venous outflow until new venous channels can form. There are only a few reports in the literature describing the use of the medicinal leech as a replacement for venous outflow in microvascular free flaps of the head and neck, with the majority of these case reports focusing on the replantation of traumatically avulsed ears . This report describes our experience using the medicinal leech for salvage of microvascular free flaps used in head and neck reconstruction that have an absent venous outflow or have failed surgical revision.
2
Materials and methods
This study was approved by the Mayo Clinic Institutional Review Board.
2.1
Patient population
A retrospective review of the medical record was conducted to identify all patients undergoing therapy with medicinal leeches for venous congestion following microvascular free flap reconstruction or replantation of traumatically avulsed tissue between January 2002 and December 2008 at our institution. Venous congestion was identified using multiple criteria including increasing edema, ecchymosis, brisk capillary refill, normal to elevated temperature, and brisk bleeding of dark blood following pin prick.
The medical record was reviewed; and patient data were extracted including age, sex, indication for surgery, type of surgery, complications, additional procedures, and follow-up. Specifics of leech therapy were obtained from reviewing patients’ medication administration record in addition to transfusion records and laboratory data. Operative reports were reviewed to extract the type and vessels used for venous and arterial anastomoses. Data are presented as median values (minimum-maximum) where appropriate.
2.2
Leech therapy
Medicinal leeches ( H medicinalis ) were obtained from Leeches USA Ltd (Westbury, NY; www.leechesusa.com ) and are kept in a small but constant supply for emergency use. Leeches are stored in refrigerated (<20 o C) distilled or bottled spring water with 2 g of Hirudo salt (Leeches USA Ltd) added to each gallon of water. The water is changed 3 times per week. Leeches are dispensed as needed to the floor where they are stored in refrigerated containers until use. Before application, any blood clots on the area to be treated are removed with dry 4 × 4 gauze. Alcohol swabs are avoided because they interfere with the leech latching onto the patient. The leech is grasped with gloves or a nontoothed forceps and placed on the area to be treated. If the leech is reluctant to attach, the flap can be pricked with a needle to induce bleeding that facilitates attachment of the leech. If the leech refuses to attach within 60 minutes, the prescribing physician is notified, as this may signify impaired arterial circulation. Once the leech attaches, it is allowed to feed and will generally detach once it has lost its blood supply or is fully distended ( Fig. 1 A). Leeches are monitored every 10 to 15 minutes to ensure that they remain at the site of attachment. Once detached, the leech is killed by placing it in 70% isopropyl alcohol and discarded. Blood clots over areas of previous bites are removed periodically to promote continued bleeding from the sites. Additional leeches are placed on the flap once the previous bite sites cease bleeding, which varies from 30 minutes to 4 to 5 hours. Free flaps are treated with leech therapy until sustained improvement of the venous congestion is noted, at which time leech therapy is gradually weaned over the course of 1 to 3 days unless the free flaps show signs of worsening venous congestion. All patients are placed on antibiotic prophylaxis for Aeromonas hydrophila for the duration of leech therapy. Patients’ hemoglobin levels were monitored every 6 hours, and patients were transfused to maintain their hemoglobin at levels greater than 10.0 g/dL. The extent of leech therapy was individualized to each patient based on the response of the tissue being treated. Two leeches were attached to each flap initially and replaced approximately every hour after detachment. Flaps were monitored for signs of continued venous congestion or improvement, and leech therapy was adjusted accordingly.
2
Materials and methods
This study was approved by the Mayo Clinic Institutional Review Board.
2.1
Patient population
A retrospective review of the medical record was conducted to identify all patients undergoing therapy with medicinal leeches for venous congestion following microvascular free flap reconstruction or replantation of traumatically avulsed tissue between January 2002 and December 2008 at our institution. Venous congestion was identified using multiple criteria including increasing edema, ecchymosis, brisk capillary refill, normal to elevated temperature, and brisk bleeding of dark blood following pin prick.
The medical record was reviewed; and patient data were extracted including age, sex, indication for surgery, type of surgery, complications, additional procedures, and follow-up. Specifics of leech therapy were obtained from reviewing patients’ medication administration record in addition to transfusion records and laboratory data. Operative reports were reviewed to extract the type and vessels used for venous and arterial anastomoses. Data are presented as median values (minimum-maximum) where appropriate.
2.2
Leech therapy
Medicinal leeches ( H medicinalis ) were obtained from Leeches USA Ltd (Westbury, NY; www.leechesusa.com ) and are kept in a small but constant supply for emergency use. Leeches are stored in refrigerated (<20 o C) distilled or bottled spring water with 2 g of Hirudo salt (Leeches USA Ltd) added to each gallon of water. The water is changed 3 times per week. Leeches are dispensed as needed to the floor where they are stored in refrigerated containers until use. Before application, any blood clots on the area to be treated are removed with dry 4 × 4 gauze. Alcohol swabs are avoided because they interfere with the leech latching onto the patient. The leech is grasped with gloves or a nontoothed forceps and placed on the area to be treated. If the leech is reluctant to attach, the flap can be pricked with a needle to induce bleeding that facilitates attachment of the leech. If the leech refuses to attach within 60 minutes, the prescribing physician is notified, as this may signify impaired arterial circulation. Once the leech attaches, it is allowed to feed and will generally detach once it has lost its blood supply or is fully distended ( Fig. 1 A). Leeches are monitored every 10 to 15 minutes to ensure that they remain at the site of attachment. Once detached, the leech is killed by placing it in 70% isopropyl alcohol and discarded. Blood clots over areas of previous bites are removed periodically to promote continued bleeding from the sites. Additional leeches are placed on the flap once the previous bite sites cease bleeding, which varies from 30 minutes to 4 to 5 hours. Free flaps are treated with leech therapy until sustained improvement of the venous congestion is noted, at which time leech therapy is gradually weaned over the course of 1 to 3 days unless the free flaps show signs of worsening venous congestion. All patients are placed on antibiotic prophylaxis for Aeromonas hydrophila for the duration of leech therapy. Patients’ hemoglobin levels were monitored every 6 hours, and patients were transfused to maintain their hemoglobin at levels greater than 10.0 g/dL. The extent of leech therapy was individualized to each patient based on the response of the tissue being treated. Two leeches were attached to each flap initially and replaced approximately every hour after detachment. Flaps were monitored for signs of continued venous congestion or improvement, and leech therapy was adjusted accordingly.
