Laparoscopic surgery for solitary insulinoma in the absence of IOUS

Insulinomas are the most common pancreatic neuroendocrine neoplasms. In spite of adequate pre-operative localisation, conventional surgical methods rely on intraoperative palpation. Intraoperative ultrasonography (IOUS) is said to aid in accurate localisation, decreases morbidity. Laparoscopic removal of pancreatic endocrine neoplasms is beneficial due to magnification and minimal invasion; however, in the absence of IOUS, error of judgement may lead to conversion to open surgery, thereby relying on 'palpation method' to localise the tumour. We combined laparoscopic surgical removal of insulinomas using an innovative method of 'laparoscopic finger palpation' with intraoperative blood glucose monitoring and frozen section for surgical cure.

Patients were evaluated and investigated by the department of endocrinology and referred for surgical management of insulinoma. Pre-operative localisation of insulinoma was done by either contrast-enhanced computerised tomography angiogram - arterial and venous phase, or endoscopic ultrasound (EUS) or DOTATATE scan. Intraoperative localisation was done by laparoscopic dissection and 'laparoscopic finger palpation'. After enucleation, the specimen was sent for frozen section, and in the interim period, serial monitoring of blood glucose was done by the anaesthetist. Maintenance of glucose levels for more than 45 min after enucleation and confirmation of neuroendocrine tumour on frozen section was the end point of surgical procedure.

A total of 19 patients were subjected to laparoscopic removal of solitary insulinomas. Enucleation was performed in 16 patients successfully. In three patients, laparoscopic distal pancreatectomy was performed. Three patients had pancreatic duct leak, of which two patients responded to conservative approach and the third patient required drainage by USG-guided pigtail catheter. All patients are cured of their disease and no patient has had recurrence so far.

Multidisciplinary approach involving laparoscopic palpation, frozen sections and intraoperative blood sugar monitoring helps laparoscopic management of solitary insulinomas without IOUS.