Introduction : Intraductal papillary mucinous neoplasm (IPMN) has malignant potential and needs surgical resection if necessary. Main pancreatic duct (MPD) size in IPMN is key risk factor to determine the surgery, but preoperative studies have many limitations to evaluate ductal systems. As direct visualization, the intraoperative pancreatoscopy (IOP) can help the surgeon to perform a complete resection in treating IPMN with inconclusive main pancreatic duct involvement

Methods : 35 pancreaticoduodenectomy underwent for IPMN patients between January 2014 and December 2017. IOP was done for selected 12 patients who have inconclusive preoperative imaging finding of MPD involvement. Patients were divided into two groups depending on whether using IOP or not. The clinicopathologic features and oncologic outcomes are retrospectively reviewed between two groups.

Results : Minimally invasive surgical resection was performed 6 cases (50%) in the IOP group. IOP group had a significantly larger main duct size (10.9?.2 vs 5.8?.8, p=0.021) and higher main and mixed type rates (Branch/Main+Mixed, 3/9 vs 16/7, p=0.017). Disease free survival rates did not differ significantly between two groups (p=0.684). During the follow up period, there was a 1 recurrence in each group; 1 patient who died of carcinomatosis in the without IOP group and 1 patient who still alive at last follow up in the IOP group.

Conclusions : IOP is feasible and safe modality to applicable in even minimally invasive approach. The selective use of IOP can optimize the surgical outcome in providing the additional findings of main pancreatic duct status of remnant pancreas and correlating with margin status.