To keep the muscle from falling back to its natural state, doctors also place an electrode on the nerve leading to the transplanted gracilis and attach it to a pacemaker-like stimulator in the patient's abdomen.
When activated, the stimulator sends electric impulses to keep the sphincter closed. When the stimulator is shut off via remote control, the muscle relaxes, allowing the bowels to open.
Galvin said he can actually relieve himself when the stimulator is still on but it's easier when it's off.
"There are lots of people in the same situation as me that potentially this operation can help," he said. "It changed my life again."
According to the U.K. charity, Bowel & Cancer Research, which Williams chairs and which funded Galvin's procedure, the technique has helped about 180 patients at the Royal London Hospital over the past 20 years.
American doctors say that though the operation has been studied in the United States, the technique is not widely practiced here.
Dr. Robert Cima, a colorectal surgeon with the Mayo Clinic in Rochester, Minn., estimated that about half a dozen centers in the United States have performed similar operations involving the gracilis and a stimulator since the late 1990s.
But though they found that it was a feasible treatment for fecal incontinence, it led to a number of post-operative downsides. It is estimated that about a third of patients will have some type of complication, he said.
Though 50 percent to 60 percent of the patients were able to remain continent while the stimulator was on, he said the main problem was keeping the muscle stimulated. Sometimes the wires connecting the stimulator the muscle would break, other times the muscle just wouldn't tolerate the constant stimulus, he said.
"Most of the patients who have incontinence are not like this gentleman," Cima said about Galvin, who said he was very fit at the time of his accident. "He was the ideal candidate."
Many patients with incontinence, he said, are older women who experienced fecal incontinence after childbirth. The lack of a strong gracilis muscle and other damaged nerves and muscles around the anus might compromise the technique's effectiveness, he added.
For most patients, he said, other treatments for incontinence suffice.
He also emphasized that many people in the United States have colostomy bags, like the one Galvin used to have, and enjoy a high quality of life.
"Their quality of life is similar to that of Americans in general," he said. "It all depends on your mindset."
Even though people don't talk about it, he said tens of thousands of Americans live with a colostomy bag or something similar.
"It's not like it was 20, 30 years ago. The technology and our understanding of how to construct a good ostomy have changed drastically," he said.
For his part, Galvin acknowledges that it's "a personal thing," but added," It just gave me my confidence back and basically gave me my life back."