Technological Advances in Lymphatic Surgery: Bringing to Light the Invisible

Sir: We read with great interest the article on technological advances in lymphatic surgery by Singhal et al.1 This study provides readers an updated review on the latest technologies available for lymphatic mapping that aid surgeons in preoperative planning and intraoperative execution of lymphatic surgery. As elegantly and didactically explained by Singhal et al., nowadays the different methods available for tracing lymphatic channels are based on the use of dye/contrast agents, which allows us to “bring to light the invisible.” In fact, peripheral lymphatic channels are very tiny (0.2 to 0.8 mm), translucent/transparent structures with usually a tortuous course that makes their identification not easy using only the naked eye. The great concern in lymphaticovenular anastomosis surgery is represented by the ability to find the best incision sites on the affected limb, which means the presence of a large lymphatic channels and a venule with a favorable pressure gradient. Hand-held technology such as indocyanine green lymphography is able to let lymphatic channels to be visualized only in the subset of patients affected by mild to moderate lymphedema and usually in distal limb sites. Nuclear-based, radiography-based, and magnetic resonance technologies do not give real-time information, which makes them more useful during patient work-up rather than for preoperative planning. In our multicentric experience with over 170 cases of lymphovenous anastomosis performed in our centers, ultrasound technology represents our standard for preoperative planning of lymphovenous anastomosis, as this tool is able to locate and preoperatively study both lymphatic channels and recipient venules, thus being of great help for planning incision sites where infrared-based technologies (indocyanine green and vein visualizer) cannot.2–5 In cases where indocyanine green lymphography can provide linear images, the marked collectors’ diameter, depth, and quality can be further analyzed with ultrasonography, whereas in cases where only dermal backflow patterns are visualized (moderate to severe lymphedema), ultrasonography can be used to directly search large lymphatic channels, which allows for optimal surgery and impressive clinical results, even in advanced cases with some preserved lymphatic channels, as pioneered by Hayashi et al.3 Moreover, once the lymphatic channel to be bypassed is found and selected, the ultrasound technology allows a favorable recipient venule along its course to be precisely located.5 In our experience, ultrasound technology represents the quintessence in lymphaticovenous anastomosis because of advances in technology, such as ultrahigh-frequency ultrasound, which provides 48- and 70-MhZ probes for clear visualization in the very superficial layers and also for future potential laser-based coupling technologies (Fig. 1). (See Figure, Supplemental Digital Content 1, which shows high-fidelity intraoperative findings during preoperative ultrahigh-frequency ultrasound planning of the lymphatic channel either for position and for size, https://links.lww.com/PRS/D784.)Fig. 1.: A 48-year old woman with left upper extremity lymphedema scheduled for lymphaticovenular anastomosis. Indocyanine green lymphography showed an immediate diffuse dermal backflow with no linear pattern. Surgery was thus planned using only ultrahigh-frequency ultrasound with a 70-MhZ linear probe. The blue mark indicates the recipient venule, the green mark indicates the lymphatic channel (diameter, 0.33 mm) (square on the right), and the black mark indicates the planned skin incision.DISCLOSURE The authors have no financial interest to declare in relation to the content of this communication. Giuseppe Visconti, M.D., Ph.D.Dipartimento Scienze della Salute della Donna, del Bambino e di Sanità PubblicaUOC Chirurgia PlasticaUniversità Cattolica del “Sacro Cuore” – FondazionePoliclinico Universitario A. Gemelli IRCSSRome, Italy Akitatsu Hayashi, M.D.Department of Breast CenterKameda Medical CenterKamogawa, Japan Alessandro Bianchi, M.D.Marzia Salgarello, M.D.Dipartimento Scienze della Salute della Donna, del Bambino e di Sanità PubblicaUOC Chirurgia PlasticaUniversità Cattolica del “Sacro Cuore” – FondazionePoliclinico Universitario A. Gemelli IRCSSRome, Italy