I read an article that researchers have grown the first artificial functional sphincter muscle from human cells in a laboratory. It has working nerves to control it, and they were able to transplant it into mice where it continued to function, and blood vessels formed to feed it like a normal body part. They are working on the lower digestive tract sphincters, but it seems like this technique could also be used to replace the lower esophageal sphincter to cure GERD.
I'm sure this is years away from being implantable into humans as a replacement valve, but it's encouraging that advances like this are being made. I for one would love to get a brand new working replacement LES valve someday. An advancement like that would make fundoplication obsolete.
Here's a link to the article:
www.sciencedaily.com/releases/2011/08/110809132220.htm