The Confluence Point: a new incision strategy for lymphaticovenular anastomosis in peripheral lymphedema.

Background: In the last five years, many advances has been made in terms of preoperative planning using new imaging technologies. The high case load of lymphaticovenular anastomosis (LVA) performed using ultrahigh frequency ultrasound bring us to find a new incision site, the confluence point, where two major functional lymphatic channels merges into one than becomes sclerotic soon after.

Patients and methods: From October 2021 to May 2022, 60 consecutive patients affected by extremity lymphedema who underwent LVA were prospectively assessed. Preoperative planning included ICG lymphography (ICG-L) and Ultra-high frequency ultrasound (UHFUS). The LVAs at the confluence points were evaluated in terms of operative time and LVA dynamics after the anastomosis, and compared to the incisions without confluence points.

Results: The confluence point was preoperatively detected in 26 (43%) cases. The lymphatics proximal to the confluence point showed similar calibers to the distal ones, with no significant size increase, and underwent a lumen obstruction 0.5 to 1 cm after the confluence point in 22 (92%) cases. The mean operative times for LVA at the confluence points was 39 ± 8 minutes in ULL and 42 ± 6 minutes in LLL, significantly lower compared to the incisions with 2 anastomoses that was 57 ± 8 minutes for ULL (p<0.0001) and 69 ± 15 minutes for LLL (p<0.0001).

Conclusion: The LVA of confluence points derives from the ultimate anatomical findings detectable by Ultra High-Frequency Ultrasound, and showed to be an effective method to minimise the number of LVA while maintaining the maximal lymph flow and the best dynamics through the anastomosis.Level of Evidence: IV, therapeutic study.