Development of a clinically useful mechanical leech device that promotes flap survival in an animal model of venous-congested skin flaps

The authors describe the design and testing of a mechanical leech device that has shown greater efficacy in alleviating venous congestion and promoting skin flap survival than previously described clinical therapies. Abdominal skin flaps (3 x 6 cm) were raised on Sprague-Dawley rats and were subjected to two ischemic events that simulated clinical venous congestion. The animals received two treatments with the device prototype during 7-day experiment (N = 9). Flap perfusion was monitored with a scanning laser Doppler imager (LDI) and was normalized to adjacent skin perfusion. Photographic images of flaps at 7 days were assessed for areas of nonnecrotic tissue, and LDI data consisted of perfusion measurements at nine time points during the 7-day experiment. The device prototype was able to promote an average survival area in the flap of 60.0 +/- 3.5%, which was not only a significant (p < 0.05) increase over previously published control groups (8.0 +/- 5.0%) that did not receive any treatment, but was a significant increase over the same treatment schedule with clinically used leeches (34.6 +/- 7.3%). At 7 days, LDI data showed flap perfusion to be 65.6 +/- 7% of adjacent skin perfusion, a significant increase over this level at the end of the second ischemic event (21 +/- 1%; p < 0.05). These results suggest that this device could be used clinically to alleviate venous congestion and to promote flap survival. The device could also be useful for prophylactic treatments and to minimize treatment delays because its long shelf-life permits immediate availability when a treatment decision is made.     

Evaluation of clinically applicable exsanguination treatments to alleviate venous congestion in an animal skin flap model

This study compares the effectiveness of alleviating venous congestion with mechanically-made outlets or leech therapy in promoting skin flap survival. Free flaps of abdominal skin (3 x 6 cm) were raised on Sprague-Dawley rats and subjected to ischemic events, simulating venous congestion. Animals received 1) no treatment; 2) two treatments involving two 18-gauge needle-puncture outlets; or 3) two sessions of leech therapy. Flap perfusion was monitored with a scanning laser Doppler flowmeter. Photographic images of flaps at 7 days were assessed for areas of normal tissue (n = 15), and laser Doppler flowmeter data consisted of control (n = 6), outlet (n = 6), and leech (n = 7). Both the needle-puncture outlet (40.0% +/- 9.24%) and leech treated (34.6% +/- 7.34%) groups had a significantly greater surviving skin area than untreated control flaps (8.0% +/- 5.0%), with 2 of 15 flaps receiving mechanical outlets exhibiting > 90% surviving area. After 7 days, laser Doppler flowmeter data showed greater mean perfusion in the outlet (71.7% +/- 16.8%) and leech (92.6% +/- 17.2%) treated groups, compared to controls (15.2% +/- 10.2%). There was a significant increase in perfusion in the outlet (13.3% +/- 6.2%) and leech (9.1% +/- 1.1%) treated groups from the end of secondary ischemia to day 7 (p < 0.05) compared to controls. The results suggest that two spatially separated outlets are as effective as one leech in increasing the area of surviving skin in venous congested flaps.     

Outcomes of flap salvage with medicinal leech therapy

Medicinal leech therapy (MLT) to salvage venous congestion in native skin and local flaps is commonly practiced. However, the role of MLT in compromised regional and free flaps remains unclear. Leeches were used in 39 patients to treat venous congestion in native skin (n = 5), local flaps (n = 6), regional flaps (n = 14), and free flaps (n = 14). There were no total losses in patients with compromised native skin or local flaps. One patient who had received a radial forearm free flap expired before flap outcome could be assessed, and was excluded from analysis. Of the remaining 27 regional and free flaps, 33.3% were salvaged, 33.3% were partially salvaged, and 33.3% were lost. Means of 38.3 ± 34.0, 101.0 ± 11.2, and 157.9 ± 224.4 leeches and 1.7 ± 3.6, 3.2 ± 4.4, and 5.6 ± 5.2 units of blood were required for the salvaged, partially salvaged, and lost groups, respectively. Twenty-two patients required blood transfusion (57.9%). No patients developed wound infection with Aeromonas hydrophilia. Two patients developed donor site hematomas, and four patients developed recipient site hematomas. MLT is efficacious in congested native skin and local flaps. Some regional and free flaps can be totally or partially salvaged. However, the morbidity of MLT must be weighed against the risks of flap loss.     

Delayed leech-borne infection with Aeromonas hydrophilia in escharotic flap wound.

Medicinal leeches (Hirudo medicinalis) are commonly used in plastic surgery for the salvage of congested flaps and replanted parts compromised by venous congestion. Infection associated with leech therapy is a documented complication of leech application, with reported incidences ranging from 2.4 to 20% [De Chalain TM. Exploring the use of the medicinal leech: a clinical risk-benefit analysis. J Reconstr Microsurg 1996;12(3):165-72.1]. We describe a case of delayed leech-borne infection, from the escharotic portion of a latissimus dorsi flap, which developed several days after stopping leech therapy for venous congestion in a reconstructed breast.     

活体水蛭吸血疗法临床应用8例

目的总结并探讨应用活体水蛭吸血疗法救治皮瓣静脉淤血的临床疗效。方法对进行性加重的皮瓣静脉淤血,采用活体水蛭置于皮瓣表面吸吮血液,待皮瓣血运明显改善后结束治疗。结果1991年1月至2006年12月,临床应用8例,除1例皮瓣远端边缘部分出现小面积坏死外,其余7例均取得良好的治疗效果。结论活体水蛭吸血疗法是一种简单、直接、较为廉价的救治皮瓣静脉淤血的方法。     

Heparin-soaked gauze to salvage congested flaps: the poor man’s leech

An important and broad area of plastic surgery entails the cover of defects by pedicled or free flaps and the revascularisation of amputated parts of the body. Failure of perfusion in flaps and replants, due to venous congestion, presents a problem even to the most experienced surgeon. Many bleeding techniques have been used to relieve venous congestion after replantation and transplantation. The best known bleeding technique is probably the use of the medicinal leech. However, the use of leeches may present problems such as infection and significant blood loss. Instead, we advocate the use of heparin soaked gauzes on an intentionally de-epithelialized part of the congested flap. Over the last 12 months, we successfully applied this method in five cases. A full report on one of these cases is provided. Received: 1 December 1999 / Accepted: 1 February2000     

Experimental studies of skin flaps with subcutaneous veins

The authors have previously reported that skin flaps with subcutaneous veins nourished by arterial or venous inflow survived, despite being sited on recipient beds with poor circulation. In these previous studies, experimental models were based on axial pattern flaps of rabbit ears. However, for clinical application, there are problems in the use of axial pattern flaps with central vessels. This report classifies skin flaps with subcutaneous veins and produces experimental models that are suitable for clinical application and investigation of survival rates. Thirty-seven rabbits (74 ears) were used in this study. A 3.0-cm x 4.5-cm skin flap with only a "passing" vein (one that traveled through the tissue without major branches to that tissue) was raised at the level of the perichondrium on the dorsum of the auricular cartilage. The flaps were divided into three groups: Group A--composite flaps (n = 10); Group B--totally venous perfused flaps (n = 30); and Group C--afferent arterialized venous perfused flaps (n = 34). More than 80 percent of the flaps became necrotic in Group A. In Group B, 18 of 20 survived with partial superficial necrosis and two became more necrotic. In Group C, 18 of 21 flaps survived with superficial necrosis and three became more necrotic. Microangiographically, as concerns the "passing" veins in Groups B and C flaps, all of the flaps survived with only superficial necrosis. The skin flaps with subcutaneous veins survived as total venous perfusion flaps (TVPF) and as arterialized afferent venous perfusion flaps (AAVPF) even though the artery was not included in the flap. The experimental model is suitable for the investigation of the clinically unconventional flap.     

Determining the appropriate number and duration of leech therapy in congested tissues using tissue spectrophotometry and laser Doppler flowmetry

A universal protocol determining the number of leeches and their application time does not exist. The aim of this study, therefore, is to quantify perfusion dynamics in venous congested tissues after leech application to get more detailed information about changes due to leech‐induced skin microcirculation and to evaluate the usability of the Oxygen to See (O2C) device in terms of determining the appropriate number of leeches and the duration of therapy. Twelve patients with the need for leech therapy participated in the study. Perfusion dynamics of the congested tissue was assessed using the O2C device, which determines blood flow (BF), the relative amount of hemoglobin (rHB), and the oxygen saturation (SO2). Measurements were carried out before leech application and on various intervals like 10 minutes, one hour, and three hours after leech application. The leech application effectuated after 10 minutes a nonsignificant perfusion improvement, which further increased after one hour with a significant reduction of the relative amount of hemoglobin and a significant increase of blood flow and oxygen saturation (BF= +56.7%; rHB= ?25.5%; SO2= +53.7%). After three hours, the values returned to the levels before leech administration. In two cases, in which further administration of leeches within the measurement period was necessary, no substantial perfusion changes were obtained. The results of this study forms a more precise pattern of microcirculatory changes of leech therapy in congested tissues. According to our measurements a venous drainage improvement can be expected in congested tissue one hour after leech administration. The O2C seems to be a useful method to determine the appropriate number and duration of leech therapy.     

Leech therapy and bleeding wound techniques to relieve venous congestion

Temporary restoration of capillary skin blood flow can be established by using leeches or by the creation of a dermal wound and the promotion of continued bleeding from the wound site in a flap with venous occlusion. An increasing restoration of capillary flow occurred with initial application of the leech and tended to exceed other techniques of restoring flow. However, all techniques of exsanguination, including leech therapy, restored very low perfusion over a two-hour course of therapy for a volume of tissue simulating a distal finger replant. The temporary increase in flap perfusion with a single leech application was greatest during the feeding activity of the leech and tapered off after the leech was satiated, to approximate flows achieved with local heparin injection and a punch wound.     

The use of leeches for treatment of venous congestion of the nipple following breast surgery

The medicinal leech,Hirudo medicinalis, played a central role in the evolution of medieval and folk medicine. Today, for the first time in history, the leech actually has a real and valuable purpose in medicine as a useful adjunct for the plastic surgeon: It provides relief of venous congestions. For over 2000 years, leeches were needlessly applied for a multitude of maladies as an adjunct to blood-letting. Their use in Europe peaked between 1830 and 1850, however, shortages led to a subsequent decline in leech application. Today there is a real clinical use for leeches which had led to a resurgence in their use in plastic surgery. Plastic surgeons use leeches in microsurgery to salvage congested flaps, whose viability is uncertain due to venous congestion. We present our experience with two patients where leeches were used to treat isolated venous engorgement of the nipple following breast surgery. Leech therapy is painless, well tolerated, and does not result in significant scarring. Prompt initiation of treatment is mandatory and produces dramatic resolution of venous congestion.     

The use of a new perfusate in experimental microvascular flaps: a threefold increase in ischemic tolerance.

The benefit of perfusion washout in both experimental and clinical skin flaps has long been debated. By perfusing ischemic rat pedicled flaps with UW solution, a recently developed, high-molecular-weight, organ-preservation medium, a 170 percent increase in the critical ischemia time of treated versus untreated control flaps was demonstrated. Sixty rats were used in this study. A 3- x 6-cm unilateral abdominal skin flap based on the superficial inferior epigastric artery and vein was raised. The flaps were divided into three groups: Group 1 (control--no perfusion washout (n = 15); Group 2 (LR)--perfusion washout with lactated Ringer's solution (n = 15); Group 3 (UW)--perfusion washout with UW solution (n = 30). Flaps were subjected to varying periods of ischemia, ranging between 8 and 30 hr. The primary ischemia time at which 50 percent of the flaps survived clinically was 10 hr for Group 1, 15 hr for Group 2, and 27 hr for Group 3. The differences between the survival rates for flaps in Groups 1, 2, and 3 were statistically significant (p less than .0005). By bathing the vascular and parenchymal cells in an impermeant preservation solution, it was hypothesized that cellular swelling would be inhibited, thereby significantly improving a skin flap's tolerance to warm ischemia. Furthermore, after reviewing the pertinent literature, it is evident that the primary critical ischemia time of 27 hr is the highest reported to date for the normothermic experimental rat pedicled flap. Clinical application of these findings, as well as the need for further studies, are discussed.     

Leeches: controlled trial in venous compromised rat epigastric flaps.

Leeches were studied for their efficacy to improve survival of venous compromised rat skin flaps. In 22 rats, bilateral epigastric island flaps were created and subjected to 6 h of venous occlusion. One flap in each animal was randomised to leech treatment, while the contralateral flap served as its own control. Flap survival, leech feeding time, weight gained by the leech and bleeding time from leech bites were measured. The area of flap survival was significantly increased in leech treated flaps compared to contralateral controls (n = 22 pairs, p = 0.03; Wilcoxon signed rank test). Weight gained in the feeding leech averaged 1.3 +/- 0.2 g (n = 18). Leech feeding time was 107 +/- 13 min (n = 18). Bleeding time from each leech bite averaged 79 +/- 12 min (n = 18). Hence, the extent of flap necrosis resulting from venous impairment can be partly diminished by leech treatment until definitive surgical venous revascularisation.     

Failure of pentoxifylline to enhance skin flap survival in the rat

The effect of pentoxifylline, a hemorheological agent that increases erythrocyte flexibility and augments capillary blood flow, on the survival of the dorsal skin flap of the rat was studied. An experimental group received intraperitoneal injections of pentoxifylline twice daily, 50 mg/kg/day, and a control group was given identical volumes of saline. Standard McFarlane flaps sized 4 x 9 cm (n = 22) and narrower 2 x 6-cm flaps (n = 18) were constructed 14 days later. After a postoperative observation period of 7 days, no significant difference in tissue survival between the pentoxifylline-treated animals and the controls was found in either flap model. Fourteen days preoperative treatment with pentoxifylline appeared to have no effect on flap survival.     

Comparisons of medicinal leech therapy with venous catheterization in the treatment of venous congestion of the sural flap

Introduction: The originally described distally based sural flap technique has a risk of partial or total flap necrosis as high as 25%. The purpose of this study was to compare the medicinal leech therapy (MLT) with venous catheterization (VC) for blood volume removal, infection, wound dehiscence, and flap necrosis in the distally based sural flap with venous congestion. Patients and methods: Fifty‐six conventional distally based sural flaps with venous congestion during reconstructive surgeries were randomly divided into two groups, MLT group and VC group. The results of comparisons were analyzed using SPSS software (SPSS for Windows Ver.11.5). Results: There were significant differences in terms of the average volume of removed blood (53.6cc vs.172.2cc), infection (10.7% vs. 34.6%), wound dehiscence (10.7% vs. 42.3%), flap necrosis (3.6% vs. 19.2%), and nursing (7.8 vs. 5.19) and patient's satisfaction (8.03 vs. 5.6) in the VC group and MLT group, respectively. Although local heparin irrigation was performed in the VC group, the catheter was exchanged in 10 patients due to obstruction by clot. Conclusion: It is recommended that the VC be used for congested pedicled flaps instead of leech therapy, as VC is more effective, easy, and safe in blood removal, and it has less complication. © 2010 Wiley‐Liss, Inc. Microsurgery, 2011.     

Antibiotic sensitivities of Aeromonas hydrophila cultured from medicinal leeches

Increased use of medicinal leeches (Hirudo medicinalis) for the treatment of venous congestion in flaps and replanted parts has coincided with reports of soft tissue infections following leech application. We cultured the gullets of 20 medicinal leeches to re-examine the antibiotic sensitivities of Aeromonas hydrophila, the leech enteric organism associated with reported infections. These isolates reflected reported resistance to penicillin and first generation cephalosporins as well as sensitivity to gentamicin, tetracycline and chloramphenicol. Additionally, the cultures were sensitive to cefamandol, cefoxitin and two third generation cephalosporins (cefoperazone and cefotaxime). These findings suggest that cefamandol, cefoxitin and some third generation cephalosporins may have a role as perioperative antibiotics in replantation and flap surgery. These antibiotics might provide prophylaxis against Aeromonas hydrophila infection when leech use is required.     

Expansion of surviving skin paddle of neurocutaneous island flaps in rats by VEGF

The purpose of this study was to investigate whether vascular endothelial growth factor (VEGF) can enlarge the skin paddles of neurocutaneous flaps in rats. Wistar albino rats were used in four groups: Group 1, (n = 10): neurocutaneous island flap; Group 2, (n = 10): neurocutaneous island flap, surgical delay; Group 3, (n = 10): neurocutaneous island flap, VEGF; Group 4, (n = 10): graft. A 3 x 3-cm, neurocutaneous island flap was elevated on the anterolateral skin of the thigh of the rats. The surviving flap areas were 29.7 +/- 1.43 percent in Group 1, 41.3 +/- 3.24 percent in Group 2, 94.2 +/- 1.46 percent in Group 3. There were no surviving areas in Group 4. The vascular networks of Group 3 animals were more intensive and diffused on microangiography and the histopathologic findings were better in this group. The surviving flap areas in Group 3 animals were enlarged approximately three times over the original size.     

The use of medicinal leeches in the salvage of flaps with venous congestion.

The use of medicinal leeches (Hirudo medicinalis) for the salvage of tissues with venous congestion has been intermittent over the last two centuries. During the last decade, interest in leech therapy has undergone a resurgence. Hirudo's tricuspid bite injects a highly potent anticoagulant. The site usually bleeds for 1 to 2 hours and under special circumstances may bleed for up to 24 hours. This collective series presents four patients in whom immediate postoperative venous congestion threatened the survival of three tissue replants and one latissimus dorsi flap. Two of the replants were completely salvaged; the other two failed due to infection. Hirudo medicinalis is an important adjunct in preventing flap or replant failure secondary to venous congestion, but its use is associated with significant risks.     

Hirudo Medicinalis and the plastic surgeon.

Medicinal leech therapy is an ancient craft that dates back to ancient Egypt and the beginnings of civilisation. The popularity of Hirudo Medicinalis has varied throughout history, reaching such a peak in Europe in the early 19th century that supplies were exhausted. During the latter half of the 19th century, their use fell out of favour, as they did not fit in with the emerging concepts of modern medicine. Leeches have enjoyed a renaissance in the world of reconstructive microsurgery during recent years, and their first reported use in alleviating venous engorgement following flap surgery was reported in this journal [M Derganc, F Zdravic, Venous congestion of flaps treated by application of leeches, Br J Plast Surg 13 (1960) 187]. Contemporary plastic and reconstructive surgeons in units throughout the United Kingdom and Ireland continue to use leeches to aid salvage of failing flaps. We carried out a survey of all 62 plastic surgery units in the United Kingdom and the Republic of Ireland to assess the current extent of use, and to investigate current practice. We have shown that the majority of plastic surgery units in the UK and Ireland use leeches post-operatively and that the average number of patients requiring leech therapy was 10 cases per unit per year. Almost all units use antibiotic prophylaxis, but the type of antibiotic and combination used is variable. We outline current practice and suggest a protocol for the use of leeches. Whilst the use of leeches is widespread, the plastic surgery community has progressed little in defining indications for their use or in achieving an accepted protocol for their application in units throughout the UK and Ireland.     

Adenovirus-mediated transforming growth factor-beta ameliorates ischemic necrosis of epigastric skin flaps in a rat model

BACKGROUND: Gene therapy has been recently introduced as a novel approach to treat ischemic tissues by using the angiogenic potential of certain growth factors. We investigated the effect of adenovirus-mediated gene therapy with transforming growth factor-beta (TGF-beta) delivered into the subdermal space to treat ischemically challenged epigastric skin flaps in a rat model. MATERIAL AND METHODS: A pilot study was conducted in a group of 5 animals pretreated with Ad-GFP and expression of green fluorescent protein in the skin flap sections was demonstrated under fluorescence microscopy at 2, 4, and 7 days after the treatment, indicating a successful transfection of the skin flaps following subdermal gene therapy. Next, 30 male Sprague Dawley rats were divided into 3 groups of 10 rats each. An epigastric skin flap model, based solely on the right inferior epigastric vessels, was used as the model in this study. Rats received subdermal injections of adenovirus encoding TGF-beta (Ad-TGF-beta) or green fluorescent protein (Ad-GFP) as treatment control. The third group (n = 10) received saline and served as a control group. A flap measuring 8 x 8 cm was outlined on the abdominal skin extending from the xiphoid process proximally and the pubic region distally, to the anterior axillary lines bilaterally. Just prior to flap elevation, the injections were given subdermally in the left upper corner of the flap. The flap was then sutured back to its bed. Flap viability was evaluated seven days after the initial operation. Digital images of the epigastric flaps were taken and areas of necrotic zones relative to total flap surface area were measured and expressed as percentages by using a software program. RESULTS: There was a significant increase in mean percent surviving area between the Ad-TGF-beta group and the two other control groups (P < 0.05). (Ad-TGF-beta: 90.3 +/- 4.0% versus Ad-GFP: 82.2 +/- 8.7% and saline group: 82.6 +/- 4.3%.) CONCLUSIONS: In this study, the authors were able to demonstrate that adenovirus-mediated gene therapy using TGF-beta ameliorated ischemic necrosis in an epigastric skin flap model, as confirmed by significant reduction in the necrotic zones of the flap. The results of this study raise the possibility of using adenovirus-mediated TGF-beta gene therapy to promote perfusion in random portion of skin flaps, especially in high-risk patients.     

带皮穿支血管的皮神经营养血管皮瓣的临床应用

目的探讨带皮穿支血管与皮神经营养血管相结合的皮瓣手术方法及临床应用效果。方法以深部知名血管发出的皮肤穿支为皮瓣转轴点,切取皮神经营养血管带蒂皮瓣或岛状皮瓣,转位修复肢体远端皮肤软组织缺损创面。结果临床已应用43例,其中腓动脉穿支腓肠神经营养血管皮瓣13例,面积30 cm×12 cm~16 cm×8 cm;胫后血管穿支隐神经营养血管皮瓣9例,面积17 cm×9 cm~5 cm×4 cm;以骨间前血管腕背穿支前臂背侧皮神经营养血管皮瓣8例,面积16 cm×6 cm~10 cm×4 cm;以掌指动脉指蹼穿支手背皮神经营养血管逆行皮瓣13例,皮瓣面积6.0 cm×3.5 cm~2.5 cm×1.5 cm;皮瓣完全成活42例,1例因静脉回流障碍远端1/4坏死。随访6~24个月,皮瓣质地优良,外形与功能恢复满意。结论该术式结合了穿支蒂皮瓣与皮神经营养血管皮瓣的优点,扩大了皮瓣切取面积与修复范围,皮瓣设计灵活,切取方便,血供可靠,是修复肢体皮肤软组织缺损的一种可取的方法。