Role of the Cadaver Lab in Lymphatic Microsurgery Education: Validation of a New Training Model.

BACKGROUND: Microsurgical transplantation of vascularized lymph nodes (VLNT) or lymphatic vessels (VLVT) alongside derivative lymphaticovenous procedures are promising approaches for treatment of lymphedema. However, clinically relevant training models for mastering these techniques are still lacking. Here we describe a new training model in human cadaver and validate its use as training tool for microsurgical lymphatic reconstruction. METHODS: 10 surgeons with previous exposure to microsurgery were trained in a controlled environment. Lymphatic vessel mapping and dissection in 4 relevant body regions, harvesting of five different VLNTs and one VLVT were performed in 5 fresh-frozen cadavers. The number of lymphatic vessels and lymph nodes for each VLNT were recorded. Finally, the efficacy of this model as training tool was validated using the Dundee Ready Education Environment Measure (DREEM). RESULTS: The average cumulative DREEM score over each category was 30,75 (max = 40) while individual scoring for each relevant category revealed highly positive ratings from the perspective of teaching (39,3), training 40,5 (max = 48) and self perception of the training 30,5 (max = 32) from all participants. The groin revealed the highest number of lymphatic vessels (3.2 ± 0.29) as all other regions on the upper extremity, while the gastroepiploic VLNT had the highest number of lymph nodes (4.2 ± 0.37). CONCLUSIONS: This human cadaver model represents a new, reproducible "all-in-one" tool for effective training in lymphatic microsurgery. Its unique diligence in accurately reproducing human lymphatic anatomy, should make this model worth considering for each microsurgeon willing to approach lymphatic reconstruction.

Collagen (NeuraGen®) nerve conduits and stem cells for peripheral nerve gap repair.

Collagen nerve guides are used clinically for peripheral nerve defects, but their use is generally limited to lesions up to 3 cm. In this study we combined collagen conduits with cells as an alternative strategy to support nerve regeneration over longer gaps. In vitro cell adherence to collagen conduits (NeuraGen(®) nerve guides) was assessed by scanning electron microscopy. For in vivo experiments, conduits were seeded with either Schwann cells (SC), SC-like differentiated bone marrow-derived mesenchymal stem cells (dMSC), SC-like differentiated adipose-derived stem cells (dASC) or left empty (control group), conduits were used to bridge a 1cm gap in the rat sciatic nerve and after 2-weeks immunohistochemical analysis was performed to assess axonal regeneration and SC infiltration. The regenerative cells showed good adherence to the collagen walls. Primary SC showed significant improvement in distal stump sprouting. No significant differences in proximal regeneration distances were noticed among experimental groups. dMSC and dASC-loaded conduits showed a diffuse sprouting pattern, while SC-loaded showed an enhanced cone pattern and a typical sprouting along the conduits walls, suggesting an increased affinity for the collagen type I fibrillar structure. NeuraGen(®) guides showed high affinity of regenerative cells and could be used as efficient vehicle for cell delivery. However, surface modifications (e.g. with extracellular matrix molecule peptides) of NeuraGen(®) guides could be used in future tissue-engineering applications to better exploit the cell potential.

Lymphatic microsurgical preventing healing approach (LYMPHA) for primary surgical prevention of breast cancer-related lymphedema: over 4 years follow-up.

Breast cancer-related lymphedema (LE) represents an important morbidity that jeopardizes breast cancer patients' quality of life. Different attempts to prevent LE brought about improvements in the incidence of the pathology but LE still represents a frequent occurrence in breast cancer survivors. Over 4 years ago, Lymphatic Microsurgical Preventing Healing Approach (LYMPHA) was proposed and long-term results are reported in this study. From July 2008 to December 2012, 74 patients underwent axillary nodal dissection for breast cancer treatment together with LYMPHA procedure. Volumetry was performed preoperatively in all patients and after 1, 3, 6, 12 months, and once a year. Lymphoscintigraphy was performed in 45 patients preoperatively and in 30 also postoperatively after at least over 1 year. Seventy one patients had no sign of LE, and volumetry was coincident to preoperative condition. In three patients, LE occurred after 8-12 months postoperatively. Lymphoscintigraphy showed the patency of lymphatic-venous anastomoses at 1-4 years after operation. LYMPHA technique represents a successful surgical procedure for primary prevention of arm LE in breast cancer patients.

Evolution of chylous fistula management after neck dissection.

PURPOSE OF REVIEW: The present review is focused on the management of lymphatic, chylous, and thoracic duct lesions following head and neck surgery, with particular attention to these complications after neck dissection. Postoperative scenarios may include chylous fistula, chylothorax, chylomediastinum, chylopericardium, lymphocele, persistent lymphorrhea, and secondary lymphedema. RECENT FINDINGS: There is a paucity of literature on the treatment of lymphatic, chylous, and thoracic duct injuries following head and neck surgery; however, this review suggests that the most appropriate treatment should include both conservative and surgical approaches. Nonsurgical options consist of low-fat diet with medium-chain triglycerides, total parenteral nutrition, careful monitoring of fluid and electrolytes, drainage of the leakage, somatostatin analogs such as octreotide, and negative-pressure wound therapy. On the other hand, surgical management includes therapeutic percutaneous lymphography-guided thoracic duct cannulation and embolization, thoracic duct ligation, excision and imbrication of leaking lymphatics, chylous fistula surgical/microsurgical repair, fistula closure by locoregional flaps, video-assisted thoracoscopic surgery, thoracotomy, pleurodesis and decortication, pericardial 'window', and pleura-venous/pleura-peritoneal shunts. In addition, single or, preferably, multiple lymphovenous anastomoses may be taken into account. SUMMARY: The various possible clinical presentations of such challenging lymphatic, chylous, and thoracic duct injuries require an appropriate multidisciplinary approach by experienced teams. Primary prevention of these complications can be achieved through adequate surgical planning to minimize lesions, including structured and thorough patient assessment, and centralization of resources and teams.