American Association of Endocrine Surgeons- Annual Meeting Abstract Papers

A PROSPECTIVE EVALUATION OF LAPAROSCOPIC EXPLORATION WITH INTRAOPERATIVE ULTRASOUND (IOUS) AS A TECHNIQUE FOR LOCALIZING SPORADIC INSULINOMAS
Grover, Skarulis MC, Alexander HR, Pingpank J, Bartlett DL, Javor ED, Chang R, Shawker T, Gorden P, Cochran C and Libutti SK
National Institutes of Health, Bethesda, MD

Description: Localization of an insulinoma is important for a successful surgical resection. Conventional pre-operative imaging studies such as computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) localize these lesions in < 50% of patients. Studies such as arteriography with calcium stimulation and venous sampling (ASVS) localize > 90% of insulinomas but require specialized expertise and an invasive procedure. This prospective study evaluated the utility of laparoscopic exploration with IOUS as the sole localization procedure in patients with biochemically confirmed sporadic insulinoma.
Methods: Between March 2001 and October 2004, 14 patients (F: 7, M: 7; mean age: 53y) with hypoglycemia and a biochemical diagnosis of insulinoma were enrolled on an IRB approved protocol. Patients with previous pancreatic surgery, MENI or suspected malignancy were excluded. CT, MRI, US and ASVS were performed pre-operatively in all patients. A surgeon, blinded to the Results: of the localizing studies, performed a laparoscopic exploration with IOUS. At the completion of the exploration, the success of laparoscopy for localization was scored and the blind broken. Resection of the tumor was then performed.
Results: Eleven of 14 tumors were successfully localized prior to laparoscopy with a combination of non-invasive and invasive studies (non-invasive - 7/14, invasive - 11/14). Exploratory laparoscopy with IOUS successfully localized 12 of 14 tumors. For the 2 lesions not localized intraoperatively, invasive imaging pre-operatively localized one and both invasive imaging and CT localized the other. All lesions were resected and laparoscopic resection was possible in 2 of 14 patients. At a median follow up of 36 months all patients demonstrated a biochemical cure.
Conclusions: Laparoscopic exploration using IOUS identified 85% of tumors. We recommend that once a biochemical diagnosis of insulinoma is made, patients undergo a CT scan and then a laparoscopic exploration with IOUS. Such a strategy would have localized 93% of lesions in our study. Invasive localization should be reserved for those patients who cannot be successfully localized by this approach.