Makoto Mihara, Hisako Hara, Yoshihisa Kawakami, Han Peng Zhou, Shuichi Tange, Kazuki Kikuchi, and Takuya Iida. Lymphatic Research and Biology, 2018

Main findings

• Histological changes in the collecting lymphatic vessels in lymphedema patients have classified the degree of lymphatic sclerosis into four stages: Normal type, Ectasis type, Contraction type, and Sclerosis type (NECST). In Normal type, the lymphatic vessels are translucent and usually collapse. In Ectasis type, the lymphatic vessels are dilated with an increased inner pressure. In the Contraction type, their appearance becomes cloudy and their walls become thickened. Ultimately, in Sclerosis type, the inner lumen is occluded.
• It has been previously published that that selecting proper functioning lymphatic vessels, namely Ectasis type lymphatic vessels, is crucial in effectively reducing the circumference of the affected limbs. As these studies have shown, the severity of lymphedema, effectiveness of LVA, and underlying NECST classification of the lymphatic vessels are correlated.
• The authors believe that the surgical outcome of LVA surgery can be greatly improved by determining the location of Ectasis type lymphatic vessels preoperatively.
• In this study the etiology of the subjects included 44 cases of cervical cancer, 27 cases of uterine cancer, 18 cases of ovarian cancer, 14 cases of malignancy of other origins, and 14 cases of primary lymphedema.
• The authors were able to conclude that sclerotic lymphatic vessels are more often found at the proximal end of the affected limb; hence, performing LVA at the proximal end may not yield optimal results. Moreover, they were able to show that there is no guarantee that lymphatic vessels with conditions suited for LVA can be found in the distal thigh area.
• These findings indicate that performing LVA in one fixed site may not be suitable for all of the lymphedema patients and each patient may have his or her own best site for LVA.
• It is necessary to readjust and select the most optimal site for LVA depending on the severity of the lymphedema and the preoperative lymphatic mapping images.
• Since it has been reported that anastomosis made during LVA surgery may become occluded as time passes performing LVA at multiple sites with multiple anastomoses could result in a better surgical outcome.
• The ratio of Sclerosis type vessels was more pre-dominant in Stage 3 patients when compared with the other stages. Therefore, locating suitable vessels for LVA by thorough preoperative evaluation of lymphatic function and proper lymphatic mapping is imperative in achieve a better surgical outcome in Stage 3 patients.
• In secondary lymphoedema Ectasis type vessels were more predominant in the distal end, whereas Contraction type vessels were more predominant in the proximal end of the limb. This implies that lymphatic vessel damage advanced from the proximal toward the distal end of the limb. This result supports the pathophysiology of secondary lymphedema as the oedema originates from the proximal end and advances toward the distal end of the limb.
• Such distribution pattern of lymphatic vessels was not observed in primary lymphedema patients. For primary lymphedema patients, Ectasis type vessels were more predominant in the crus compared to the thigh area, whereas Sclerosis type vessels were found only in the crus area. As previously reported, the condition of the lymphatic vessels in primary lymphedema may vary among patients.