Endoscopic sentinel lymph node biopsy in a porcine model

Objective: The objective of this study was to investigate the feasibility of endoscopic sentinel lymph node biopsy in a porcine model. Methods. One hundred microcuries of technetium-labeled sulfa colloid (Tc-SC) was injected into the right and left ventrolateral surfaces of the oral tongue of six adult Yorkshire pigs. A handheld gamma probe was used to locate the region of focal radioactivity on the neck that corresponded to the sentinel lymph node (SLN). Next, 0.25 mL of isosulfan blue dye was injected into the Tc-SC injection sites on the tongue. Endoscopic SLN dissection was then performed using a combination of balloon dissection and CO2 insufflation. The operative time, blood loss, and radioactivity of the SLN were measured for each animal. Results: The SLN was detected transcutaneously with the gamma probe, and endoscopic SLN excision was successful. Endoscopic visualization and an endoscopic gamma probe confirmed the presence of both isosulfan blue dye and radiopositivity in the SLN in each pig. The procedure lasted 22 to 61 minutes (median duration, 35 minutes). There was no measurable blood loss in any of the animals. Mean radioactivity measured 14,466 counts/second per lymph node. Conclusions: Endoscopic SLN biopsy for oral tongue lesions is feasible and warrants further study.