Microsurgical transfer of the greater omentum in the treatment of canine obstructive lymphoedema

In 13 dogs, experimental obstructive lymphoedema of the lower limb was created by combined radiotherapy and radical groin dissection. Six months later, when the degree of lymphoedema was stable, the lymphatic obstruction was bridged by microvascular insertion of a free omental graft. Six months after grafting, circumferential measurements indicated a statistically significant 38% reduction in the magnitude of lymphoedema. Biopsies showed the omental grafts were alive but contained much fibrous tissue. Lymphatic vessels were identified in 10 of 11 biopsies but connections between these lymphatics and lymphatics proximal to the graft could not be demonstrated by either lymphangiography or dye-injection techniques. The findings indicate that experimental obstructive lymphoedema in the dog can be reduced significantly by insertion of a vascularised omental graft. However, it could not be established that improvement was due to union of graft lymphatics with those of the lymphoedematous limb, although this union may have consisted of lymphatics too small to be demonstrated.     

Value of isotope lymphography in the diagnosis of lymphoedema of the leg

BACKGROUND: Isotope lymphography has largely replaced contrast lymphography in the diagnosis of lymphoedema. Its accuracy has only been assessed in small studies and it is not known if it can identify patients with a proximal lymphatic obstruction who may be suitable for lymphatic bypass surgery. METHODS: Three hundred and ninety-five patients suspected to have lymphoedema were investigated by isotope lymphography between 1985 and 1995. Contrast lymphography was also carried out in 29 of these patients because the isotope results were thought to be misleading, or because lymphatic bypass surgery was being considered. RESULTS: In the 29 patients who had both investigations isotope lymphography detected 20 of 24 abnormal lymphatic systems. Four legs with obstructed groin lymphatics were reported as normal. Two legs with normal contrast lymphograms were erroneously diagnosed as having lymphoedema in the isotope study. Detectable groin nodes on the scintigrams were indicative of either normal lymphatics or proximal lymphatic obstruction. An increase in isotope uptake over 30-60 min of less than 50 per cent, or a total absence of isotope within groin nodes, was a sensitive indicator that patients were unsuitable for lymphatic bypass surgery. CONCLUSION: Isotope lymphography is a moderately sensitive test for lymphoedema, which will mistakenly classify some normal legs as lymphoedematous. It will usually correctly identify patients who are suitable for lymphatic bypass surgery.     

Experimental and clinical study on the lymphatic pathway draining from the distal esophagus and gastric cardia

The intramural and extramural lymphatics draining from the distal esophagus and gastric cardia were studied in 140 mongrel dogs by dye injection technique. A clinical study was also performed on the lymphatic pathway in these regions by radio isotope uptake (RIU). The results were compared with that of lymph node metastases in 113 patients with carcinoma of the distal esophagus and 103 patients with carcinoma of the gastric cardia. The intramural lymphatics between the distal esophagus and gastric cardia were communicated at the central part of the muscularis mucosae. This finding coincided with the results of intramural RIU. The extramural lymphatics from the distal esophagus flowed both upward and downward. Those from the cardia entered the intraabdominal regional lymph nodes, but none was visualized either in the mediastinum or in the thoracic cavity. Similarly, few RIUs were detected in the mediastinal nodes. As the result of partial or total blockade at the cardiac portion of the stomach in dogs, ascending lymphatics reaching the thoracic cavity was observed in 6 of 27 cases. Clinically, the incidence of the mediastinal lymph node metastases were 17.0%. These results indicate that upward lymphatic spreads may occur in cases with cardiac cancer when the descending lymphatic pathway is blocked by the tumor invasion.     

Technique and proof of patency of microsurgical lympho‐lymphonodular anastomoses: A study in the rat model

Background: Lymphedemas due to local lymphatic blocks can be treated by microsurgical transplantation or transposition of lymphatic vessels. Here, the anastomoses are usually made end‐to‐end between lymphatics, but occasionally appropriate lymphatic recipient vessels are missing. In such cases, reconstructing lymph drainage by connection to a lymph node could be another technical option. The purpose of this study was to examine the patency rate of such lympho‐lymphonodular anastomoses in an experimental animal model. Methods: Male Sprague–Dawley rats were anesthetized, and the retroperitoneum was exposed. Patent blue dye was injected into the left foot to stain lymphatic structures. In group A (n = 8), the left lumbar trunk was cut centrally, the distal part was turned over to the right lumbar lymph node, and a microsurgical lympho‐lymphonodular anastomosis was performed. In group B (n = 8), the left lumbar trunk was cut. After 8 weeks, the lumbar region was surgically re‐explored, and the lymphatic drainage was examined by injection of Patent blue dye into the left lumbar lymph node. Results: In 8/8 animals of group A, patent transposed lymphatics were found. The patency of the anastomosis was proven directly by observation of blue dye transit and indirectly by observation of blue staining of the right lumbar lymph node. In 6/8 animals of group B, no lymphatic connection to the right lumbar lymphatic system was observed. Conclusions: This is the first report of the microsurgical technique and the proof of patency of lympho‐lymphonodular anastomoses. The novel animal model for testing the patency of transposed lymphatics is discussed. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.     

Microsurgery for groin lymphocele and lymphedema after oncologic surgery

Groin lymphocele (GL) is a frequent complication of inguinal lymph node dissection, and conservative treatment is not always successful. Different surgical methods have been used to treat lymphoceles arising from lymphatics injured during groin surgery. However, they all involve the closure of lymphatics merging at the lymphocele, increasing the risk of postoperative lower limb lymphedema or of worsening lymphedema if already clinically evident. We assessed the efficacy of a diagnostic and therapeutic protocol to manage inguinal lymphoceles using lymphoscintigraphy (LS) and microsurgical procedures. Sixteen GL [seven associated with leg lymphedema (LL)] were studied by LS preoperatively and treated by complete excision of lymphocele and microsurgical lymphatic‐venous anastomoses between afferent lymphatics and a collateral branch of great saphenous vein. Lower limb lymphatics were identified intraoperatively using Patent Blue dye injection. Nine patients without lymphedema had complete healing of lymphocele and no appearance of lower limb postoperative lymphedema. The other seven patients with associated secondary lymphedema had complete disappearance of lymphocele and a remarkable reduction of leg volume. Four of them completely recovered without the need of any compression garment, after the first year postoperative. Inguinal lymphocele nonresponsive to conservative treatment can be advantageously studied by LS and successfully treated by microsurgical reconstructive procedures, above all if associated to LL. © 2013 Wiley Periodicals, Inc. Microsurgery 34:10–13, 2014.     

携带淋巴结的组织瓣移植治疗下肢淋巴水肿

目的 探讨携带淋巴结的组织瓣移植治疗下肢淋巴水肿的疗效。方法 2019年6月至2021年6月,采用携带淋巴结的组织瓣移植治疗Ⅱ～Ⅲ期下肢淋巴水肿5例,皮瓣大小（10～30） cm×（4～9） cm,受区选择患肢小腿区,受区血管为胫前动脉及伴行静脉,术后定期随访。结果 1例皮瓣术后部分坏死,予以换药对症治疗后,创面瘢痕愈合,其余4例移植皮瓣顺利成活。术后随访0.5～2年,患肢周径于术后1个月及6个月平均减少0.84 cm及2.29 cm,术后未出现淋巴管炎,供区未出现淋巴漏及淋巴水肿。结论 应用淋巴结皮瓣移植治疗肢体淋巴水肿近期疗效较好,供区无并发症,是早中期下肢淋巴水肿可选择的治疗方法之一。     

A new experimental model of lymphedema in rats' hind lower legs

Summary In this study, a simple and reliable experimental model for lymphedema is described. In the middle portion of albino rats' hind lower leg, leaving the saphenous vessels and the accompanying lymphatics intact, all other soft tissues are incised circularly. After retraction of the cut ends of muscles, the skin edge of the ventral side is sutured to that of the dorsal side to envelope the muscles of both cut ends and the saphenous vessels and lymphatics. Resection of lymphatics or circular strip of soft tissues is not performed. In 48 of 50 rats' legs, measurements were made of leg circumference and the diameter of the lymphatics; in addition changes of lymphatic contractility were observed. These measurements, observations and histopathological studies showed a consistent picture of lymphedema. The clinical implication of this observation is that a small number of lymphaticovenous anastomoses will not correct lymphedema and that the quality of the results will correlate with the number of anastomoses. In studying the findings of experimental lymphedema, some other clinical phenomena are explained and modifications of the operative procedure of microlymphaticovenous anastomosis for treating lymphedema are suggested.     

The pathomechanism of posttraumatic edema of the lower limbs: II--Changes in the lymphatic system

BACKGROUND: The peripheral lymphatic system reacts to penetrating microorganisms and self-antigens released from tissues and cells damaged by trauma or intracellular pathogens. The response of regional lymph nodes to tissue trauma has not been thoroughly studied. We investigated the changes in lower limb lymphatics and nodes after fractures and soft tissue injuries. This type of injury is frequently complicated by limb edema. Posttraumatic edema of lower limbs is characterized by long-lasting swelling of the limb, erythema, and increased skin temperature at the site of injury. This suggests that a local inflammatory process is proceeding, even though the process of bone or soft tissue healing is considered to be completed. METHODS: Twenty-one patients with closed lower limb bone fractures and soft tissues injuries were studied by means of isotope lymphography. RESULTS: Dilated lymphatics of the entire limb were found in all patients, and 62% of them showed enlarged inguinal lymph nodes. Venous thrombosis was found in 24% of cases. There was no correlation between the degree of lymphatic dilatation, lymph node enlargement, and bone fracture or soft tissue injury or venous thrombosis. Surgical intervention was not an independent factor for lymph node enlargement. CONCLUSION: This study has shown that although the fracture or injured tissues are clinically healed, local inflammatory reaction at the site of injury persists and cytokine signals are sent to the regional lymph nodes.     

Anatomical and Surgical Concepts in Lymphatic Regeneration

Chronic post-surgical lymphedema is common condition that afflicts nearly 2 million Americans. In the USA, it is most commonly encountered in the upper extremities of patients who have undergone axillary lymph node dissection for breast cancer. Lymphedema has a significant negative effect on cosmesis, limb function, and overall quality of life. Despite the impact of this condition, very little is known about how to effectively prevent or treat lymphedema. While therapeutic options for chronic extremity lymphedema remain limited, several surgical approaches have been suggested. These include techniques aimed at reducing limb volume, as well as techniques that aim to reconstitute disrupted lymphatic channels. Operations proposed to re-establish lymphatic continuity include lymphatico-venous anastomoses, lymphatico-lymphatico anastomoses, and tissue transfer.     

Types of lymphoscintigraphy and indications for lymphaticovenous anastomosis

Several authors have reported the usefulness and benefits of lymphoscintigraphy. However, it is insufficient to indicate microvascular treatment based on lymphedema. Here, we present the relationships between lymphoscintigraphic types and indications for lymphatic microsurgery. Preoperative lymphoscintigraphy was performed in 142 limbs with secondary lymphedema of the lower extremity. The images obtained were classified into five types. Type I: Visible inguinal lymph nodes, lymphatics along the saphenous vein and/or collateral lymphatics. Type II: Dermal backflow in the thigh and stasis of an isotopic material in the lymphatics. Type III: Dermal backflow in the thigh and leg. Type IV: Dermal backflow in the leg. Type V: Radiolabeled colloid remaining in the foot. Lymphaticovenous anastomosis was performed in 35 limbs. The average number of anastomoses per limb was 3.3 in type II, 4.4 in type III, 3.6 in type IV, and 3 in type V. The highest number of anastomosis was performed in type III. In conclusion, type III is suggested to be the best indication for anastomosis compared with types IV and V.     

Primary intrapelvic lymphaticovenular anastomosis following lymph node dissection

Lymphedema of lower extremities occurs following surgical resection of malignant tumors and intrapelvic lymph node dissection and is a long-term problem for patients. We performed primary intrapelvic lymphaticovenular anastomosis to prevent postoperative leg lymphedema. The procedures were conducted in 7 patients (aged 35-61 years) with cancer of the uterine body. After completion of hystero-oophorectomy and intrapelvic lymph node dissection, the afferent lymphatics entering internal and external iliac lymph nodes were end-to-end anastomosed with branches of the deep inferior epigastric veins. The time taken for constructing 4 anastomoses was 100 to 120 minutes. The follow-up period ranged from 10 to 18 months (mean, 14 months). All patients were discharged and are independent in daily living. Apart from mild leg lymphedema in 1 patient, no lymphedema was observed in other patients up to the last follow-up. This surgical modality is effective in preventing lymphedema in lower extremities after intrapelvic para-aortic lymph node dissection.     

Lymphatic Drainage of the Peritoneal Space: A Pattern Dependent on Bowel Lymphatics

Background Understanding lymph drainage patterns of the peritoneum could assist in staging and treatment of gastrointestinal and ovarian malignancies. Sentinel lymph nodes (SLNs) have been identified for solid organs and the pleural space. Our purpose was to determine whether the peritoneal space has a predictable lymph node drainage pattern. Methods Rats received intraperitoneal injections of near-infrared (NIR) fluorescent tracers: namely, quantum dots (designed for retention in SLNs) or human serum albumin conjugated with IRDye800 (HSA800; designed for lymphatic flow beyond the SLN). A custom imaging system detected NIR fluorescence at 10 and 20 minutes and 1, 4, and 24 hours after injection. To determine the contribution of viscera to peritoneal lymphatic flow, additional cohorts received bowel resection before NIR tracer injection. Associations with appropriate controls were assessed with the χ² test. Results Quantum dots drained to the celiac, superior mesenteric, and periportal lymph node groups. HSA800 drained to these same groups at early time points but continued flowing to the mediastinal lymph nodes via the thoracic duct. After bowel resection, both tracers were found in the thoracic, not abdominal, lymph node groups. Additionally, HSA800 was no longer found in the thoracic duct but in the anterior chest wall and diaphragmatic lymphatics. Conclusions The peritoneal space drains to the celiac, superior mesenteric, and periportal lymph node groups first. Lymph continues via the thoracic duct to the mediastinal lymph nodes. Bowel lymphatics are a key determinant of peritoneal lymph flow, because bowel resection shifts lymph flow directly to the intrathoracic lymph nodes via chest wall lymphatics. Dr. Parungo was the recipient of an award at the SSO meeting.     

The pathomechanism of posttraumatic edema of lower limbs: I. The effect of extravasated blood, bone marrow cells, and bacterial colonization on tissues, lymphatics, and lymph nodes

BACKGROUND: The mechanical injury of soft tissues and bones of lower extremities is frequently followed by long-lasting edema at the site of trauma and distally. The pathomechanism of this complication remains unclear. Venous thrombosis and interruption of lymphatics are considered to be the main etiologic factors. We propose a concept that protracted healing of injured tissues and bones with involvement of the regional lymphatic system (lymphatics and nodes) is responsible for persistence of edema. The events affecting the first (scavenging) phase of healing of traumatized tissues, such as hematoma, translocation of bone marrow cells to soft tissues, and colonization by microorganisms, and in particular their effects on lymphatics and lymph nodes, were studied. METHODS: Mongrel dogs weighing 15-20 kg were used. Fresh blood or bone marrow cell (BMC) suspension was injected subcutaneously or intralymphatically into the paw. Strains of saprophyte bacteria residing on the skin surface were cultured and injected intradermally. Oil-contrast lymphography was performed before and after injections to evaluate the changes in lymphatics and nodes. Biopsy samples of paw skin, subcutaneous tissue, and regional lymph nodes (LN) were taken. The responsiveness of LN lymphocytes was studied in autologous mixed cultures with peripheral blood lymphocytes (PBL), BMC, and cultured bacteria. RESULTS: The PBL from subcutaneously injected blood were evacuated by the lymphatic route at a rate of 1-3%/6 hr. There was no thrombosis of lymphatic vessels or obstruction of LN sinusoids. The BMC evoked major inflammatory changes in both the skin and the LN. Bacteria caused local inflammation, dilatation of lymphatics, and destruction of node parenchyma. Autologous BMC and PBL stimulated LN lymphocytes in a 6-day culture. The responsiveness of lymph node lymphocytes to previously subcutaneously injected bacterial antigens was increased. CONCLUSION: The extravasated blood did not produce changes in skin, subcutaneous tissue, and lymphatics; however, it stimulated LN lymphocytes. The BMC and saprophyte bacteria caused major local and lymph node inflammatory response. All these factors may contribute to the local edema in the initial phases of healing of traumatized tissues.     

Cardiovascular lymphoscintigraphy

The technique of lymphoscintigraphy when applied to the heart and blood vessels correlates well with results of anatomic investigations of arterial and cardiac lymphatic vessels reported in the literature. Five dogs and eight rabbits underwent lymphoscintigraphy of the heart and aorta, as well as the iliac, femoral, and tibial arteries. After surgical exposure, approximately 500 microCi of 99mTc-labelled antimony sulfide was injected into the myocardium or the adventitial-medial plane of an artery. The colloid particle size of 4 to 12 m mu causes resorption and transport only via the lymphatic vessels. Twenty-one preparations were imaged from 2 to 48 hours after administration. This method provides a functional demonstration that the tibial and femoral arteries of both species are invested with lymphatics. The first echelon of lymph nodes which drain muscular arteries are imaged within 2 hours. Regional lymph nodes could not be seen to drain the aorta or iliac arteries. Anterior left ventricular myocardial injection in the dog showed a single cardiac lymph node. This drainage pattern has been described previously by other investigators. In the rabbit a similarly placed injection visualized a group of regional cardiac nodes. Ligation of the collecting ducts afferent to the cardiac node in the dog prevented removal of the isotope from the heart at 3, 6, and 9 hours. At 24 hours the liver and spleen were imaged, the radiocolloid gaining entrance to the blood vascular system presumably via myocardial lymphaticovenous anastomoses. Lymphoscintigraphy reflects physiologic processes such as lymph transport, filtration, and reticuloendothelial function. It defines regional patterns of cardiac and arterial lymph drainage. It can confirm experimentally produced impairment of lymph drainage from a defined area of tissue. Lymphoscintigraphy should be useful in the investigation of the significance of lymph drainage to diseases of the heart and blood vessels.     

Vascularized appendicular lymph node transfer for treatment of extremity lymphedema: A case report

Vascularized lymph node transfer has demonstrated promising results for the treatment of extremity lymphedema. In an attempt to find the ideal donor site, several vascularized lymph nodes have been described. Each has a common goal of decreasing morbidity and avoiding iatrogenic lymphedema while obtaining good clinical results. Herein, we present the preliminary clinical outcomes of an intra‐abdominal lymph node flap option based on the appendicular artery and vein used for the treatment of extremity lymphedema. A 62 year‐old woman with moderate lower extremity lymphedema, on chronic antibiotics because of recurrent infections and unsatisfactory outcomes after conservative treatment underwent a vascularized appendicular lymph node (VALN) transfer. At a follow‐up of 6 months, the reduction rate of the limb circumference was 17.4%, 15.1%, 12.0% and 9% above the knee, below the knee, above the ankle and foot respectively. In addition, no further episodes of infection or other complications were reported after VALN transfer. Postoperative lymphoscintigraphy demonstrated that the VALN flap was able to improve the lymphatic drainage of the affected limb. According to our findings, the use of VALN transfer minimizes donor‐site morbidity, avoids iatrogenic lymphedema and may provide a strong clearance of infection because of the strong immunologic properties of the appendiceal lymphatic tissue in selected patients. Despite these promising results, further research with larger number of patients and longer follow‐ up is needed.     

MR淋巴造影术诊断肢体淋巴水肿

目的 探讨新的能够反映形态学和功能改变的淋巴循环系统疾病的影像诊断方法.方法 皮内注射钆贝葡胺注射液后采用Philip 3.0T MR成像仪进行扫描,观察淋巴结和淋巴管的形态改变和功能状况,包括淋巴液在管内的流速和腹股沟淋巴结内造影剂充盈的动态性改变.结果 30例门诊肢体淋巴水肿患者接受了检查,原发性下肢淋巴水肿27例,继发性淋巴水肿3例.注射造影剂后所有的患肢淋巴管均显影,原发性淋巴水肿肢体的淋巴管形态变异较大.测得的淋巴的流速为0.30～1.48 cm/min.患侧腹股沟淋巴结造影剂浓度显著低于健侧.造影剂在患侧淋巴结内达到峰值的时间和排除的时间均明显较健侧延迟.此外,患侧淋巴结内有造影剂部分充盈和髓质区先充盈等异常发现.结论 采用钆贝葡胺造影剂的MR淋巴造影是形态和功能兼备的肢体淋巴循环障碍疾病的检查方法.     

MR淋巴造影术诊断肢体淋巴水肿

目的 探讨新的能够反映形态学和功能改变的淋巴循环系统疾病的影像诊断方法.方法 皮内注射钆贝葡胺注射液后采用Philip 3.0T MR成像仪进行扫描,观察淋巴结和淋巴管的形态改变和功能状况,包括淋巴液在管内的流速和腹股沟淋巴结内造影剂充盈的动态性改变.结果 30例门诊肢体淋巴水肿患者接受了检查,原发性下肢淋巴水肿27例,继发性淋巴水肿3例.注射造影剂后所有的患肢淋巴管均显影,原发性淋巴水肿肢体的淋巴管形态变异较大.测得的淋巴的流速为0.30～1.48 cm/min.患侧腹股沟淋巴结造影剂浓度显著低于健侧.造影剂在患侧淋巴结内达到峰值的时间和排除的时间均明显较健侧延迟.此外,患侧淋巴结内有造影剂部分充盈和髓质区先充盈等异常发现.结论 采用钆贝葡胺造影剂的MR淋巴造影是形态和功能兼备的肢体淋巴循环障碍疾病的检查方法.     

MR淋巴造影术诊断肢体淋巴水肿

目的 探讨新的能够反映形态学和功能改变的淋巴循环系统疾病的影像诊断方法.方法 皮内注射钆贝葡胺注射液后采用Philip 3.0T MR成像仪进行扫描,观察淋巴结和淋巴管的形态改变和功能状况,包括淋巴液在管内的流速和腹股沟淋巴结内造影剂充盈的动态性改变.结果 30例门诊肢体淋巴水肿患者接受了检查,原发性下肢淋巴水肿27例,继发性淋巴水肿3例.注射造影剂后所有的患肢淋巴管均显影,原发性淋巴水肿肢体的淋巴管形态变异较大.测得的淋巴的流速为0.30～1.48 cm/min.患侧腹股沟淋巴结造影剂浓度显著低于健侧.造影剂在患侧淋巴结内达到峰值的时间和排除的时间均明显较健侧延迟.此外,患侧淋巴结内有造影剂部分充盈和髓质区先充盈等异常发现.结论 采用钆贝葡胺造影剂的MR淋巴造影是形态和功能兼备的肢体淋巴循环障碍疾病的检查方法.     

An experimental study of surgical treatment for lymphedema in rats: A modified Kinmonth procedure and autologous lymph node capsule-venous anastomosis with lymph node transfer.

This study was carried out in order to determine the effect of various surgical procedures on lymphedema in a rat model. In 26 adult male Sprague-Dawley rats, randomly divided into four groups, surgical lymphedema was created in the left hind limbs.: The control group had no drainage, Group 1 had a conventional Kinmonth operation, Group 2 had a modified Kinmonth operation using the greater omentum and Group 3 had autologous lymph node capsule-venous anastomosis with lymph node transfer. Circumference measurement was performed to calculate percent difference and circumferential reduction rate. In Groups 2 and 3, patent blue violet was injected to identify lymphatics. In all groups, hematoxylin-eosin (H-E) and 5'-nucleotidase stainning were done to evaluate lymphatics histopathologically. The percent difference and the circumferential reduction rate respectively showed the smallest and largest values in Group 2. A significant difference was found between the control group and Group 2 (p < 0.05). Lymphatic vessels were shown by patent blue violet injection in Groups 2 and 3. H-E and 5'-nucleotidase staining revealed patency of lymphatics. A modified Kinmonth procedure using the greater omentum was the most effective procedure for early lymphedema in a rat model and autologous lymph node capsule-venous anastomosis with lymph node transfer was effective for lymph draining in certain conditions, so it may assist in elucidating surgical treatment of lymphedema.     

Lymphaticolymphatic anastomosis.

Lymphaticovenous anastomosis has proved valuable in the treatment of obstructive lymphedema. Histological studies of this anastomosis have shown the lymphatic component to be almost inactive in anastomotic healing. In order to clarify the role of the lymphatics, experimental lymphaticolymphatic anastomoses were performed in canine femoral lymphatics. The technique developed calls for eight to ten 19 mu sutures to prevent vessel wall collapse, and preservation of the vasa vasorum. Vessels were harvested from one hour to six weeks after anastomosis. Scanning electron microscopy and conventional light histology revealed the lymphatics to have active healing of the intima with complete reendothelialization by two weeks. The techniques developed in this study are directly applicable to human lymphaticovenous anastomosis.