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Critical Ischemia Time, Perfusion, and Drainage Function of Vascularized Lymph Nodes

Yang, Chin-Yu, M.Sc.; Ho, Olivia A., M.D.; Cheng, Ming-Huei, M.D., M.B.A.; Hsiao, Hui-Yi, Ph.D.

Plastic and Reconstructive Surgery: September 2018 - Volume 142 - Issue 3 - p 688–697
doi: 10.1097/PRS.0000000000004673
Experimental

Background: Vascularized lymph node transfer is a promising surgical treatment for lymphedema. This study investigated the effect of ischemia on the lymphatic drainage efficiency of vascularized lymph node flaps and the critical ischemia time of lymph nodes.

Methods: Twenty-four lymph nodes containing groin flaps in 12 Sprague-Dawley rats were dissected. Clamping of the vascular pedicle was performed for 0, 1, 3, 5, 6, or 7 hours; then, each was allowed to reperfuse by means of the vascular pedicle for 1 hour. Perfusion and ischemic changes were assessed using indocyanine green lymphography; laser Doppler flowmetry; and histologic studies with associated lymphatic vessel endothelial hyaluronan receptor-1, CD68, 4′,6-diamidino-2-phenylindole, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling, and glutathione assay stains.

Results: The mean latency period of the groin lymph node flaps was 247 ± 67, 83 ± 15, 72 ± 42, 30 ± 18, and 245 ± 85 seconds in the 0-, 1-, 3-, 5-, and 6-hour groups, respectively. Perfusion detected by laser Doppler was 85.2 ± 14.5, 87.2 ± 36.7, 129.8 ± 33.7, 140.4 ± 148.5, 156.1 ± 91.4, and 41.2 ± 34.8 perfusion units at ischemia times of 0, 1, 3, 5, 6, and 7 hours, respectively. Cell damage measured by glutathione was 46.8 ± 10.2, 67.7 ± 14.2, 62.8 ± 15.4, 126.6 ± 5.9, 259.0 ± 70.3, and 109.1 ± 27.5 at ischemia times of 0, 1, 3, 5, 6, and 7 hours, respectively. Histologically, as ischemia time increased, hemorrhage and congestion became more severe.

Conclusions: The critical ischemia time of vascularized lymph nodes is 5 hours in the rodent animal model, verified by indocyanine green lymphatic fluid uptake, laser Doppler perfusion, and histologic assessments. Interestingly, lymphatic drainage and perfusion of vascularized lymph nodes were improved with an increased ischemia time before the critical 5 hours was reached.

Taoyuan, Taiwan

From the Center for Tissue Engineering, Chang Gung Memorial Hospital; and the Division of Reconstructive Microsurgery, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine.

Received for publication July 25, 2017; accepted February 26, 2018.

The first two authors contributed equally and should be considered co–first authors.

Presented at the 9th Congress of the World Society for Reconstructive Microsurgery, in Seoul, Republic of Korea, June 14 through 17, 2017; and the 2018 American Society of Reconstructive Microsurgery Annual Meeting, in Phoenix, Arizona, January 13 through 16, 2018.

Disclosure: The authors have no financial interest to declare in relation to the content of this article.

Hui-Yi Hsiao, Ph.D., Center for Tissue Engineering, Chang Gung Memorial Hospital, College of Medicine, Chang Gung University, 5, Fu-Hsing Street, Kueishan, Taoyuan 333, Taiwan, ivyhsiao@gmail.com

©2018American Society of Plastic Surgeons