Aug. 13--A long-used surgical technique to treat cranial nerve disorders proved successful in easing diabetes symptoms in a small group of patients, according to a study published Thursday by a leading neurosurgeon at Allegheny General Hospital.
Seven of 10 patients with type 2 diabetes showed significant improvement in their blood sugar levels following surgery to relieve arterial pressure on the lower half of the brain. That part of the brain controls the function of the pancreas, the organ that regulates insulin.
"This is something that we can use to help people live better," said Dr. Peter Jannetta, the pioneer neurosurgeon who has used the technique to treat face pain and vertigo. He cautioned that the surgery needs to be done by experienced surgeons, and patients with diabetes should understand how to control type 2 diabetes, an illness in which the pancreas does not produce enough insulin. "The main thing is going to be prevention."
One patient, John Horrell of Fairfield, said prior to the surgery doctors warned him he would have to go on insulin to control blood sugar readings of 250. He couldn't see well, and he was constantly tired. Doctors put him on maximum doses of metformin, an anti-diabetic drug. After the surgery, his symptoms nearly vanished, and he stopped taking the medication.
"Without the surgery, I'd be on insulin, there's no question about it," said Horrell, 72, who owns a hardware and building supplies business in Ligonier. He blames his inactive lifestyle for having to go back on metformin and another diabetes drug since the surgery, but his sugar levels have stabilized under 120. "I think the operation helped a lot."
During the surgery, known as microvascular decompression, doctors drill a hole the size of a nickel just behind the ear. They place a tiny implant made of silicon rubber and Teflon to hold the artery away from the brain and the 10th cranial nerve, called the vagus.
Jannetta has used this technique in about 6,000 surgeries, dating to his days at the University of Pittsburgh Medical Center. There, he performed the surgeries for this study, which took years to finalize.
In a previous study, Jannetta found that arterial compression of the medulla oblongata, the base of the brain, affected the pancreas and its ability to produce insulin. That discovery led him to propose that surgery could help regulate blood sugar.
Researchers followed patients in the study for 12 months and did not permit them to change their diets or activity levels. Jannetta said the next step is to study more people in different locations to corroborate the findings.
Dr. Sunil Patel, chair of the department of neurosciences at the Medical University of North Carolina, said more investigation is needed before a conclusive link can be established between the brain stem's compression and type 2 diabetes.
"The observations presented are valuable starting points for questions related to the exact location of arterial compression relevant to type 2 diabetes mellitus, the best experimental measure of response, and the subset of patients most likely to benefit from microvascular decompression surgery," Patel said in an accompanying editorial in the journal Surgical Neurology International, where the study was published.
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