Reverse lymphatic mapping during robotic inguinal lymphadenectomy for the prevention of lymphedema

Penile squamous cell carcinoma (SCC) is a rare malignancy with a high propensity for regional dissemination. While current guidelines recommend inguinal lymph node dissection (ILND) for patients with high-risk features, the surgery carries a high risk of lymphedema 1. Indocyanine Green (ICG)-guided lymphangiography has been used to increase nodal yield and detection rates in lymph node dissections 2. To demonstrate that "reverse" ICG-guided ILND is a safe and novel technique that may reduce rates of postoperative lymphedema in penile cancer patients and may intraoperatively help identify candidates for lymphovascular anastomosis (LVA). To evaluate the efficacy of "reverse" ICG-guided ILND, 2.5 mg mixed ICG solution was injected superficially into the intradermal layer at the first and fourth interdigital spaces of the foot prior to beginning robotic-assisted bilateral ILND. The lower extremity lymphatic channels are prospectively identified and preserved during dissection with the aid of near infrared fluorescence imaging. A total of 9 groin dissections have been completed using this technique. Reverse lymphatic mapping was successful in 7 out of 9 (77.7 %) groin dissections. With a follow-up range of 0.9–24 months, there have been no instances of post-operative lymphedema in patients who underwent successful mapping. Reverse lymphatic mapping during robot-assisted inguinal lymphadenectomy is a safe and feasible technique. Enhanced intraoperative visualization of lymphatic structures not only may help minimize the risk of postoperative lymphedema, but it may also help identify those patients at high risk of developing lymphedema and allow for prophylactic interventions. Further investigation is necessary to establish the oncologic safety of reverse lymphatic mapping during ILND.