This is best achieved using an upper midline incision or bilateral subcostal incision to enter the abdomen. For many conditions where it is likely the that tumour is malignant, such as gastrinoma or glucagonoma, a thorough search of the abdomen is then made for evidence of metastases. Biopsies may be taken from lymph nodes or the liver, both important sites of tumour spread.
The stomach is retracted superiorly and the transverse colon inferiorly. The gastrocolic omentum, connecting these two structures, is then divided, allowing entry into the lesser sac of the abdomen.
The peritoneum is then incised, granting access to the retroperitoneum, exposing the body and tail of the pancreas. This allows the surgeon to manually palpate these parts of the pancreas to locate tumours. Intraoperative ultrasound may also be employed to more accurately locate lesions.
This is done by a Kocher manoeuvre. This is where the duodenum and the head of the pancreas are lifted off the retroperitoneum, elevating them from the inferior vena cava and aorta below. This allows the head of the pancreas to be palpated by the surgeon or examined using ultrasound.