Laser Angiography as an effective method of evaluating flap microperfusion in-vivo following Autologous Lymph Node transfer - A Single Center Experience
Kunj K. Desai, MD1, Joshua L. Levine, MD2, Julie V. Vasile, MD2, Constance M. Chen, MD2, Corinne Becker, MD3.
1Rutgers - New Jersey Medical School, Newark, NJ, USA, 2New York Eye & Ear Infirmary, New York, NY, USA, 3Lymphedema Center, Paris, France.
Lymphedema following cancer treatment has been reported to occur in upto 49% of patients. Affected extremities have increased susceptibility to infections, cellulitis, lymphangitis, erysipelas, and lymphangiosarcoma. Current treatment options include conservative management with compression bandages, massage and physical therapy as well as surgery. In addition to being labor intensive and time consuming the benefits of conservative management are dependent on long-term adherence to therapy regimen. Autologous Lymh Node transfer (ALN) is a surgical treatment method that aims to improve lymphatic flow from an extremity by the microsurgical transfer of vascular lymph nodes. First the recipient bed is prepared, then a small vascularized flap containing superficial lymph nodes is harvested from a donor site which is then microsurgically anastomosed to an artery and vein at the recipient site. While patency of the microanastomosis can be assessed grossly, no definitive method of assessing vascularized lymph node flap microperfusion has been described in the literature.
Various methods and technologies have been developed and utilized to facilitate the assessment of tissue perfusion such as lymphoscintigraphy, doppler ultrasound, CT angiography, and indocyanine green laser angiography (SPY Elite® System, LifeCell Corp., NJ).
Our aim was 1) to determine if laser angiography (SPY) is an effective in-vivo method of assessing perfusion in vascularized lymph node transfers, and if confirmed, then 2) develop a definitive protocol for the same.
From July 2011 to June 2013, a total of 36 ALN were performed at one institution by the same team (JVV, JLL, CMC) for lymphedema resulting from cancer treatment. Laser angiography using the SPY Elite® System was performed following microvascular anastomosis to confirm perfusion of the flap. In each case, an area of well-perfused fatty tissue in the recipient bed adjacent to the transferred lymph nodes is utilized as a reference area to which perfusion in the flap is compared. Fluorescent intensity in the flap is calculated as a percentage of the reference area. Flaps with perfusion intensity greater than 25% of the reference area were considered to be viable.
In all 36 patients in the series microperfusion of the flap is demonstrated and flaps were deemed to be viable. In 4 cases, microperfusion was not demonstrated initially, however, following technical revisions and repositioning this resolved.
The intra-operative use of laser angiography provides a real-time ability to assess microperfusion following autologous lymph node transfer. Correlation with clinical outcomes will need to be assessed.
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