In reading about for more information on Bingley's post regarding diaetetic, I came across this largely unrelated term:

atretic

"Having an abnormal closure or absence of a body opening or tubular organ (for example, a child born without an oesophagus would have an atretic birthdefect). "

*Note the spelling of oesophagus; I would spell it 'esophagus,' but perhaps this is a regional difference.