Detection of Efferent Lymphatic Vessels Using Gamma Probe Guidance for Efferent Lymphatic Vessel Anastomosis.

Efferent lymphatic vessel anastomosis (ELVA) is a microsurgical technique used to anastomose efferent lymphatic vessels from the inguinal lymph nodes (LNs) to the veins in patients with lower extremity lymphedema (LEL). Intraoperative detection of inguinal LNs is important when performing ELVA. Identifying inguinal LNs in patients with mild LEL is easy on palpation, ultrasonography, and indocyanine green (ICG) lymphography because the LNs are large and have good ICG uptake. In contrast, inguinal LNs of patients with advanced LEL are small and have minimal to no ICG uptake owing to lymphatic degeneration; thus, finding LNs in patients with advanced LEL is difficult, and novel techniques are required. This feasibility study evaluated the effectiveness of gamma probes and lymphoscintigraphy in these patients. Nineteen limbs were included in this study. Patients were injected with a Tc^99m isotope 24 hours before ELVA and evaluated based on the Taiwan Lymphoscintigraphy Staging (TLS). Inguinal LNs with radioisotope accumulation were looked for intraoperatively using a gamma probe. Eleven of the 19 limbs were classified as partial obstruction according to the TLS. The detection of LNs using a probe was successful in all limbs classified as partial obstruction, excluding 1 case. However, the gamma probe did not respond to inguinal LNs in limbs classified as total obstruction. In this study, the gamma probe was useful in identifying suitable inguinal LNs for performing ELVA in patients with partial obstruction findings on TLS.