Near-Infrared Lymphatic Mapping of the Recurrent Laryngeal Nerve Nodes in T1 Esophageal Cancer

Abstract

BACKGROUND: It is still unclear that dissection of recurrent laryngeal nerve nodes is mandatory in patients with cT1 middle or lower thoracic esophageal squamous cell carcinoma when the nodes are negative in preoperative staging workup. We aimed to evaluate the feasibility of near-infrared image-guided lymphatic mapping of bilateral recurrent laryngeal nerve nodes. METHODS: The day before operation, we injected indocyanine green (ICG) into the submucosal layer by endoscopy. At the time of upper mediastinal dissection, ICG-stained basins were identified along the bilateral recurrent laryngeal nerves and retrieved under guidance of the Firefly system. After the operation, remnant ICG-unstained basins were dissected from the specimen to assess the presence of metastasis. RESULTS: Of 29 patients enrolled, ICG-stained basins could be identified in 25 patients (86.2%), and 6 of them (24.0%) had nodal metastasis; 4 in the right recurrent laryngeal nerve chain, 1 in the left recurrent laryngeal nerve chain, and 1 in both recurrent laryngeal nerve chains. On pathologic examination of 345 recurrent laryngeal nerve nodes, two metastatic nodes were identified in ICG-unstained basins along the left recurrent laryngeal nerve in a patient who had lymph node metastases in ICG-stained basins along both recurrent laryngeal nerves. Negative predictive value in detection of nodal metastasis was 100% for the right recurrent laryngeal nerve chain and 98.2% for the left recurrent laryngeal nerve chain. CONCLUSIONS: Real-time assessment of recurrent laryngeal nerve nodes with near-infrared image was technically feasible, and we could detect lymphatic basins that most likely have nodal metastasis. Our technique might be useful in determining the optimal extent of lymphadenectomy.