Norwich - The William W. Backus Hospital has begun offering gastric bypass surgery for obese patients seeking to lose weight, the hospital announced Monday.

Hospital spokesman Shawn Mawhiney said Dr. Mark Tousignant has already done a few of the procedures, and more are scheduled. The procedure is the second type of bariatric surgery offered by Backus, adding to the adjustable gastric banding done there since 2010.

The hospital expects to do about 100 gastric bypass procedures annually, in addition to about 100 of the banding surgeries each year, Mawhiney said.

In the gastric bypass surgery, the stomach is divided in two to create a small upper stomach pouch, limiting the amount of food and decreasing the nutrients that are digested and absorb. The stomach pouch holds about three tablespoons of food.

"Gastric bypass is the preferred method of bariatric surgery when patients have diabetes and are insulin dependent," Tousignant said in a news release. "Individuals who have metabolic disorders, such as diabetes, have the best outcomes with bypass."

In gastric banding surgery, the stomach is made smaller by wrapping a device with a thin tube around the upper part of the stomach. The band is tightened with injections of saline fluid.

Lawrence + Memorial Hospital in New London became the first hospital in southeastern Connecticut to offer gastric bypass surgery in 2010. Since then, however, two of the lead surgeons who had been performing the surgery left L+M.

L+M spokesman Mike O'Farrell said the hospital is evaluating whether to reintroduce bariatric surgery services. The decision will be based on market needs, physician resources and other factors, he said.

For those interested in learning about bariatric surgery, Backus will host an informational session from 6 to 7 p.m. today in the Backus Outpatient Care Center at 111 Salem Turnpike. To register, call (860) 425-8740.

j.benson@theday.com