LAUSR

To The Editor, We read with great interest the article entitled “Combined pedicled superficial circumflex iliac artery perforator (SCIP) flap with lymphatic tissue preservation and lymphovenous anastomosis (LVA) for defect reconstruction and lymphedema–lymphocele prevention in thigh sarcoma surgery: Preliminary results” by Scaglioni et al. (J Surg Oncol. 2020 Sep 22). This study has revealed the effectiveness of indocyanine green (ICG) lymphography navigation for lymphatic reconstruction. Pre‐ and intra‐operative ICG lymphography revealed precise locations of the lymphatic vessels in the donor and the recipient sites, which allowed secure lymphatic reconstruction via a LVA. We completely agree with importance of ICG lymphography mapping and navigation. However, a near‐infrared camera system used in the study showed fluorescent images on a monitor, and a surgeon had to change views during lymphography navigation, which required some time and affected precise localization of the lymphatic vessels. To address this challenge, we adopted projection mapping with ICG fluorescence in localization of the lymphatic vessels for lymphatic reconstructive surgery. ICG was subcutaneously injected as previously reported for lymph flow evaluation and lymphatic mapping/navigation. A projection mapping device specialized for near‐infrared fluorescence imaging (Medical Imaging Projection System; MIPSTM) was used to visualize fluorescent images; MIPS projected fluorescent images directly on a region of interest. Fluorescent image visualized by a hand‐ held near‐infrared camera system (PDE‐neoTM, Hamamatsu Photonics) was consistent with that visualized by MIPS (Figure 1). As an examiner could see lymph flows on a lymphedematous limb, the lymph vessels could be precisely localized and marked during lymphography procedures. As pointed out by Scaglioni et al., we strongly believe that lymph circulation should be evaluated in patients undergoing combined pedicled SCIP flap with lymphatic tissue preservation and LVA for defect reconstruction and lymphedema–lymphocele prevention in thigh sarcoma surgery. Considering convenience and precision to detect lymph circulation, projection mapping with ICG fluorescence with MIPS is recommended for both pre‐ and intraoperative evaluation of lymph circulation. The image visualized by MIPS is not the same completely as image visualized by previous near‐infrared camera system. It is uncertain that MIPS visualize the true lymph circulation. And therefore, further studies are needed to evaluate the precision of MIPS.