A Feasibility Study for Mapping Ovarian Sentinel Lymph Nodes

BACKGROUND: To evaluate four methods of injecting indocyanine green (ICG) around the adnexa and identify the optimal technique for ovarian sentinel lymph node (SLN) mapping. METHOD: Patients presenting for management of an adnexal mass were prospectively enrolled. Patients with peritoneal carcinomatosis were excluded. Four injection methods were evaluated: 1) intratubal, 2) paraovarian peritoneum, 3) infundibulopelvic (IP) ligament after resection of the adnexal mass, and 4) IP ligament before resection of the adnexal mass. Two mL of ICG was injected, and at least 10 minutes of transit time was allowed. The ipsilateral and contralateral pelvic and para-aortic lymph node beds were evaluated for ICG uptake. Retroperitoneal nodal resection was performed if indicated. EXPERIENCE: Forty patients were enrolled, 10 in each group. For method 1, 20.0% of SLNs mapped, all to the ipsilateral para-aortic lymph node bed. For method 2, 10.0% mapped, only to the ipsilateral para-aortic lymph node bed. For method 3, 50.0% mapped to the ipsilateral para-aortic lymph node bed (n=3), contralateral para-aortic lymph node bed (n=1), or ipsilateral pelvic lymph node bed (n=1). For method 4, 70.0% mapped to the ipsilateral para-aortic lymph node bed (n=5) or ipsilateral pelvic lymph node bed (n=2). Surgeons reported methods 1 and 2 as cumbersome, and excessive peritoneal staining made SLN identification difficult. No injection-related complications were reported. CONCLUSION: Injection of ICG into the IP ligament before or after adnexal mass resection led to similar rates of SLN mapping and was deemed feasible by surgeons. Only one SLN was identified contralateral to the adnexal mass, and all but three mapped to the para-aortic region. Injection into the IP ligament should be evaluated in patients with likely adnexal malignancy, including SLN resection.