Kumiko Matsumoto

Demonstrating the lymphatic system in rats with microinjection

The lymphatic system plays an important role in human health and disease. In addition to a role in the immune response, the lymphatics can serve as a pathway for cancer metastasis. Visualizing the lymphatic system has been a difficult part of anatomic dissection studies. Anatomists have attempted to map the lymphatic system using various methods and materials; vivisection of dogs, injection of mercury into the skin and lymphatic vessel in cadavers, and injection of dye indirectly into the skin of dead and living specimens. In this study, we introduce a method of using a mixture of acrylic blue dye and hydrogen peroxide to visualize the lymphatic system in rats. The lymphatic vessels were cannulated with micropipettes, and radio‐opaque orange lead oxide was selectively injected. The lymphatic system became visible from the dorsal side of the hand and foot, and distal region of the tail to their termination at the left and right subclavicular veins via lymph nodes. Cisterna chyli in the abdominal cavity and thoracic duct ran along with the aorta. The advantage of this technique is that lymph nodes as well as lymphatic channels could be recorded not only photographically but also radiographically. This microinjection technique is useful for demonstrating the lymphatic system in rats and may provide further information that will help in cancer metastasis research. Anat Rec, 2011.

Evaluation of the Microvascular Research Center Training Program for Assessing Microsurgical Skills in Trainee Surgeons

Background We established the Microvascular Research Center Training Program (MRCP) to help trainee surgeons acquire and develop microsurgical skills. Medical students were recruited to undergo the MRCP to assess the effectiveness of the MRCP for trainee surgeons. Methods Twenty-two medical students with no prior microsurgical experience, who completed the course from 2005 to 2012, were included. The MRCP comprises 5 stages of training, each with specific passing requirements. Stages 1 and 2 involve anastomosing silicone tubes and blood vessels of chicken carcasses, respectively, within 20 minutes. Stage 3 involves anastomosing the femoral artery and vein of live rats with a 1-day patency rate of >80%. Stage 4 requires replantation of free superficial inferior epigastric artery flaps in rats with a 7-day success rate of >80%. Stage 5 involves successful completion of one case of rat replantation/transplantation. We calculated the passing rate for each stage and recorded the number of anastomoses required to pass stages 3 and 4. Results The passing rates were 100% (22/22) for stages 1 and 2, 86.4% (19/22) for stage 3, 59.1% (13/22) for stage 4, and 55.0% (11/20) for stage 5. The number of anastomoses performed was 17.2±12.2 in stage 3 and 11.3±8.1 in stage 4. Conclusions Majority of the medical students who undertook the MRCP acquired basic microsurgical skills. Thus, we conclude that the MRCP is an effective microsurgery training program for trainee surgeons.

Histologic Evaluation of Lymphaticovenular Anastomosis Outcomes in the Rat Experimental Model: Comparison of Cases with Patency and Obstruction.

Background: Lymphaticovenular anastomosis plays an important role in the surgical treatment of lymphedema. The outcomes of lymphaticovenular anastomosis are evaluated based on changes in edema; however, isolated assessment of the anastomosis itself is difficult. The authors used an animal experimental model to conduct a detailed examination of histologic changes associated with lymphaticovenular anastomosis and determined the factors important for success. Methods: The experimental lymphaticovenular anastomosis model was created using lumbar lymph ducts and iliolumbar veins of Wistar rats. The authors performed anastomosis under a microscope and reviewed postoperative histologic changes using optical and electron microscopy. In addition, electron microscopy and histology were used for detailed examination of the area in the vicinity of the anastomotic region in cases with patency and obstruction. Results: The patency rates immediately after, 1 week after, and 1 month after lymphaticovenular anastomosis were 100 percent (20 of 20), 70 percent (14 of 20), and 65 percent, respectively. A detailed examination of the anastomotic region with electron microscopy revealed that, in cases with patency, there was no notable transformation of the endothelial cells, which formed a smooth layer. In contrast, in obstruction cases, the corresponding region of the endothelium was irregular in structure. Conclusions: Vessel obstruction after lymphaticovenular anastomosis may be associated with irregular arrangement of the endothelial layer, leading to exposure of subendothelial tissues and platelet formation. One part of the postoperative changes after anastomosis and a cause of obstruction were elucidated in this study. The authors’ results may enable improvements in lymphaticovenular anastomosis by translating back to real clinical operations.

Iliolumbar Vein as a Training Model for Microsurgical End-to-Side Anastomosis.

Abstract Although a multitude of microsurgical training models have been reported, few experimental animal models are available for end-to-side anastomosis. In this study, the authors developed an end-to-side anastomosis rat training model that utilizes the iliolumbar vein and investigated its characteristics. Ten Wistar male rats were used as microvascular end-to-side anastomosis models. Diameters of the posterior vena cava and the root of the iliolumbar vein were measured on both sides. The mean diameter of the posterior vena cava was 5.40 mm (range, 3.2–3.6 mm). The mean diameter of the root of the iliolumbar vein was 1.12 mm (range, 1.1–1.4 mm). The mean duration of bilateral end-to-side anastomosis was 50.6 minutes (range, 48–55 minutes). The intraoperative patency rate after anastomosis was 100%. The authors described a rat training model for microsurgical end-to-side anastomosis. This model is especially useful because it closely simulates a real operation, and training can be performed relatively quickly.

A Novel Lymphaticovenular Anastomosis Rat Model

IntroductionLymphaticovenular anastomosis (LVA) has become an important procedure for the surgical treatment of lymphedema. In the past, the anatomy of the lymphatic system of animal models has been reported. However, to our knowledge, there have been few reports of animal models of LVA including training model. In this study, we report on a relatively simple and ideal animal LVA model based on peritoneal lymph ducts and veins. Patients and MethodsFor 10 rats, diameters of lumbar lymphatic ducts and iliolumbar veins in the peritoneal cavity on both sides were measured, and LVA was performed. In addition, we measured the diameters of 28 lymphatic ducts and veins in 8 patients who had previously undergone LVA and compared the results with those obtained in this rat model. ResultsThe mean diameter of the lymphatic ducts was 0.61 mm, and the iliolumbar veins were 0.81 mm. On the other hand, the mean diameters of the 28 lymphatic ducts and veins of the 8 patients in whom we performed LVA were 0.58 and 0.76 mm, respectively. The differences in the diameters of the lymph vessels and veins between the rats and patients were not statistically significant. ConclusionsWe report on an LVA model involving the use of the lumbar lymphatic duct and iliolumbar veins of rats. The diameter, nature, and placement of the anastomosis using this model are very similar to that noted during real human surgery. We believe that our rat model will be useful as a practical training model for LVA and in studies on postoperative changes in LVA.

Vascularized peripheral nerve grafting promotes myelination of regrowing optic nerve.

We investigated whether the use of vascularized peripheral nerve grafts on the optic nerve stump enhances axonal regeneration of retinal ganglion cells compared with isolated nonvascularized grafts. The rat median nerve was microsurgically sutured with its supplying artery and vein to the optic nerve stump. The number of retinal ganglion cells with regenerating axons was evaluated by retrograde labeling into the grafted peripheral nerve, and the myelination of the regenerating axon fibers was examined by electron microscopy. The number of retinal ganglion cells with regenerating axons was significantly higher in the vascularized graft than in the nonvascularized graft. The ratio of myelinated axon fibers was also increased in vascularized grafts. Thus, grafting with their supplying arteries and veins to an injured nerve stump represents a promising strategy to accelerate axonal regeneration from neurons of the central nervous system.

Exercise-Loaded Indocyanine Green Fluorescence Lymphangiography for Diagnosing Lymphedema

Background Indocyanine green (ICG) fluorescence lymphography (ICGLG) that can visualize the lymphatic vessel and its flow noninvasively and dynamically was developed in 2007. It is frequently used to observe the function and pathway of the lymphatic vessels. ICGLG is simple and easy to perform, and it is useful for understanding the condition of the lymphatic system in real time. However, its protocol is not standardized. In addition, the lymphatic flow is enhanced by an exercise load such as walking. Till now, there is no report of exercise‐loaded ICGLG. Therefore, we aimed to shorten the examination time and establish a standard ICGLG protocol. Methods We examined 63 patients (126 lower limbs) who visited our clinic for lower extremity edema. We observed detailed images of exercise‐loaded ICGLG and examined the changes in findings over time in affected legs classified according to the International Society of Lymphedema. After ICG was injected, the participants exercised for 30 minutes. We observed the farthest proximal point where any ICG could be observed and the appearance of dermal backflow (DB), which is a specific finding of lymphedema, every 5 minutes. Results The proximal migration speed of ICG tended to slow as the disease stage worsened. For all disease stages, after 20 minutes of exercise, the DB appearance rate did not change further. The rates were 0% for legs with stage 0 lymphedema, 50% for legs with stage 1 lymphedema, and 100% for legs with stages 2a and 2b lymphedema. Conclusion The appropriate exercise duration after ICG injection is 20 minutes. ICGLG is useful for screening for lymphedema.

Accelerated Lymph Flow in Early-Stage Secondary Lymphedema Detected by Indocyanine Green Fluorescence Lymphography

Background The purpose of this study was to evaluate the lymph function of the lower extremities and to identify early symptoms of lymph dysfunction in secondary lymphedema by observing lymph flow with indocyanine green (ICG) fluorescence lymphography (LG). Methods We retrospectively evaluated the lymph flow of 108 limbs in 54 female patients with leg lymphedema secondary to pelvic lymphadenectomy for gynecological carcinoma and 14 limbs in 7 female controls without a history of pelvic lymphadenectomy or radiotherapy. ICG was injected into four points at the distal part of the lower extremity. Lymph flow was evaluated by measuring the proximal point where the ICG could be observed 5 minutes after rest and 15 minutes after a walking exercise. Results In the controls, lymph flow was stable at rest and was well enhanced by exercise. In patients with early‐stage lymphedema, lymph flow was already enhanced at rest (p = 0.005) and was further enhanced by exercise. In advanced‐stage lymphedema, lymph flow was not enhanced, even by exercise (p = 0.001). Conclusion ICG‐LG could evaluate lymph flow and functions of lymph systems and detect accelerated lymph flow in early‐stage secondary lymphedema. Detecting accelerated lymph flow may facilitate early detection and treatment of secondary lymphedema.

A Detailed Examination of the Characteristics and Treatment in a Series of 33 Idiopathic Lymphedema Patients

Background To date, only a few reports have been published on idiopathic lymphedema, and most of these are case reports. In this time, we performed a retrospective review of idiopathic lymphedema patients. Methods Forty patients presented with idiopathic lymphedema that was unrelated to surgery, injury, and medical conditions such as circulatory disease, kidney disease, and thrombotic venous disease. For these patients, we performed a retrospective review for edema‐onset age, sex, location and stage of the edema, presence of cellulitis, episode related to edema onset, therapeutic intervention, and follow‐up duration in the 33 patients whom we followed up. Results Among the 33 patients with idiopathic lymphedema, there were 11 patients with either congenital or childhood‐onset lymphedema, 14 with adult‐onset lymphedema, and the remaining 8 patients had an onset age of >60 years. Twenty of the 33 patients had undergone surgical treatment. Of the 19 patients who underwent lymphaticovenular anastomosis (LVA), 2 had good, 4 had fair, and 13 had poor treatment outcomes. Twelve patients successfully received only conservative treatment and follow‐up for more than 3 months, without operation. The treatment outcome in these 12 patients was as follows: excellent in 4 patients, good in 6, and fair in 2 patients. Conclusion In this study, the usefulness of LVA for most patients with idiopathic lymphedema was not confirmed. Although this review did not include a conducted case, the indication for new surgical treatments such as vascularized lymph node transfer should be considered in the future.

Plotting dermal sutures: An easy dermal suture technique

1 Hiroshi Matsumoto, MD Yoshihiro Kimata, MD, PhD Seiji Komatsu, MD, PhD Kumiko Matsumoto, MD Min Zaw Aung, MBBS, MMedSc (Surgery) Department of Plastic and Reconstructive Surgery Graduate School of Medicine, Dentistry, and Pharmaceutical Science University of Okayama Okayama, Japan Sir: W performing dermal sutures, we aim to achieve a satisfactory postoperative scar from an aesthetic perspective and reduce surgical site infection and other postoperative complications.1–3 Although the usefulness of dermal sutures is widely recognized, some residents and general surgeons are still reluctant to use dermal sutures due to concerns regarding the time needed to master this unfamiliar technique. Therefore, we designed a plotting dermal suture (PDS) method, which can be easily applied to appropriately perform dermal suturing. With this technique, we believe that even inexperienced surgeons can make dermal sutures in a quick and easy manner.