"stoma" is indeed used in the UK to cover various "ostomies" of the gastrointestinal and urinary tracts.
Patient information is provided on "stoma care"
http://hcd2.bupa.co.uk/fact_sheets/html/Stoma...http://www.kingsch.nhs.uk/clinical/clinical.a...and "stoma care nurses"/"stoma nurses" are specially qualified healthcare workers
http://www.cancerhelp.org.uk/help/default.asp..."UK Self Help
Stoma
British Colostomy Association, Tel 0118 939 1537/Helpline 0800 328 4257
Ileostomy & Internal Pouch Support Group, Helpline 0800 0184 724
NASPCS, Tel 01560 322 024
Urostomy Association, Tel 01245 224 294"
http://www.ukselfhelp.info/?"Oldham Stoma Support Group
Description: This group aims to provide mutual advice, support and information for existing and newly diagnosed ileostomy, colostomy and urostomy patients and their families."
http://www.aditus.nhs.uk/Aditus/Patients+and+..."artificial anus" serves only as a description and would be completely inappropriate for a self-help group
e.g.
"The stoma serves the purpose of an artificial anus, or less often urinary tract opening, after the original one has been removed surgically."
http://www.timesonline.co.uk/article/0,,8124-...