Surgical Innovations

Insulinomas
Creative adaptation enables one patient to avoid major pancreatic resection.

Endocrine surgeons have excellent views of anatomical structures during laparoscopic surgery like the adrenalectomy performed here.

Insulinomas are rare tumors of the pancreas that produce too much insulin. Usually less than two centimeters in size, insulinomas are benign (noncancerous) in 90% of cases. Without treatment, however, the extra insulin causes patients' blood sugar to drop, and can cause symptoms such as weakness, tremors, anxiety, hunger, headache, and in severe cases, coma or even death.

Surgical removal of insulinomas can be performed laparoscopically depending on the size and location of the tumor. The preferred approach, enucleation, involves excising the tumor without removing (resecting) adjacent pancreatic tissue.

Yet if a tumor is located very close to the main pancreatic duct, it may be necessary to resect normal pancreatic tissue with the tumor in order to avoid an injury to the pancreatic duct. When tumors are located in the head of the pancreas, occasionally an operation called the Whipple procedure is necessary. This is a major operation involving removal of tissue from both the pancreas and the duodenum. "This is a complex reconstruction involving weeks of recovery," explains William B. Inabnet, MD, Chief, Section of Endocrine Surgery.

William B. Inabnet, MD, Chief, Section of Endocrine Surgery

In a recent case, Dr. Inabnet was able to spare a patient from having to undergo the Whipple procedure by devising a completely novel solution. The patient's tumor was located directly over the pancreatic duct, which carries pancreatic juices into the duodenum. Performing a routine enucleation would have presented a high risk of injuring this duct, potentially causing leakage and requiring additional surgery. But Dr. Inabnet believed that it might be possible to take steps to protect the duct and perform laparoscopic surgery safely. The case was discussed at the Pancreas Center's weekly clinical conference to gain a consensus for the treatment plan. After the treatment plan was finalized, Peter Stevens, MD, of the Division of Interventional Gastroenterology, placed a temporary stent into the pancreatic duct to protect it from injury during the planned operation. "The stent was placed into the main pancreatic duct without difficulty four days prior to surgery," Dr. Inabnet explains.

The solution worked beautifully. The insulinoma was successfully enucleated, and the patient did not have to undergo a major pancreatic resection. The patient experienced no complications and went home two days after surgery.

The success of this procedure was also enhanced by the use of intraoperative insulin assay — a blood test to measure insulin levels — to confirm that the tumor was completely removed. Providing real-time information to the surgeon, such monitoring provides clear measurements of the level of insulin in the blood during surgery. Once an insulinoma is removed, a patient's insulin returns to a normal level and the surgeon knows that the tumor has been completely removed.

Intraoperative hormone monitoring is particularly useful in helping surgeons rule out the possibility that multiple tumors may be present. While most insulinomas are solitary, some patients have multiple tumors that are too small to be detected through imaging. In the past, if additional tumors remained undetected after surgery, symptoms would continue and a patient would have had to return for more surgeries until all the tumors were found. Today, the ability to monitor hormones during surgery immediately confirms whether the surgeons have successfully completed the operation, or if more tumors may be present — so they can complete the operation in one sitting. "Despite the clear advantages of intraoperative hormone monitoring during pancreatic surgery, NewYork-Presbyterian Hospital/Columbia University Medical Center is one of only a handful of U.S. Centers to routinely use the technique. In addition to measuring insulin during surgery for insulinoma, Dr. Inabnet uses the equipment to measure parathyroid hormone during thyroid and parathyroid surgeries.