Hmm. One more time without using 'urlexp':
  related discussion:Urostoma
  related discussion:Stoma-Selbsthilfegruppe

Pons-Collins, Oxford-Duden:
colostomy - (Med) Kolostomie

NOAD:
stoma - ... • [Medicine] an artificial opening made into a hollow organ, esp. one on the surface of the body leading to the gut or trachea.
colostomy - a surgical operation in which a piece of the colon is diverted to an artificial opening in the abdominal wall so as to bypass a damaged part of the colon.
• an opening so formed: [as adj.] 'a colostomy bag.'
ileostomy - a surgical operation in which a piece of the ileum is diverted to an artificial opening in the abdominal wall.
• an opening so formed.

AHD:
ostomy - Surgical construction of an artificial excretory opening, as a colostomy or ileostomy.
ostomate - One who has undergone an ostomy.

M-W:
stoma - ... 3 : an artificial permanent opening especially in the abdominal wall made in surgical procedures
ostomy - : an operation (as a colostomy) to create an artificial passage for bodily elimination

Technically (as far as I can tell) an ostomy is the surgical procedure and/or the opening it creates leading into or out of the body, and the stoma is the mouth of the opening on the surface of the body.

In practice the two terms are often used interchangeably, perhaps especially in AE.

I don't know if [coll.] is the best way to convey this, but I strongly recommend including the senses actually used, not just those that may seem most technically correct.

The specific ostomies currently in LEO are not those most commonly encountered. I would suggest adding at least the rest of the abdominal ones individually. In addition to 'colostomy' above, more or less as follows:

colostomy [coll.] [med.] - das Kolostoma
ileostomy [med.] - die Ileostomie
ileostomy [coll.] [med.] - das Ileostoma
ileostomy [coll.] [med.] - künstlicher Dünndarmausgang
urostomy [med.] - die Urostomie
urostomy [coll.] [med.] - das Urostoma
urostomy [coll.] [med.] - künstlicher Harnleiterausgang

Of course there are other kinds; anyone wanting a sample can go to http://wortschatz.uni-leipzig.de/ and do a wildcard search, e.g. *ostomy in English or *ostomie/*stoma in German. For example, I'm not very clear on the difference between a nephrostomy and a urostomy, and I didn't even attempt to consider tracheostomy, much less how it differs from tracheotomy.

And there are apparently also other ostomies that involve tubes leading *into* the abdomen, often for feeding, such as enterostomy, gastrostomy or percutaneous endoscopic gastrostomy (PEG), or jejunostomy or percutaneous endoscopic jejunostomy (PEJ).

And I have no idea what the translation for 'ostomate' (person having undergone an ostomy) is.

Obviously I'm already at (or beyond) the limit of my medical knowledge. Perhaps other users with more experience in this area could help out, or at least confirm and/or correct this much. Thanks in advance. <waving to Marianne et al.> (-:

• Menschen, die einen künstlichen Darm- oder Harnleiterausgang (Stoma) haben, stehen oft vor Problemen, mit denen sie sich von einer verständnislosen Umgebung alleingelassen fühlen. (Quelle: Frankfurter Rundschau 1991)
• In Deutschland gibt es 257 Selbsthilfegruppen "Ich habe ein Loch im Bauch" - mit dieser Erkenntnis müssen Menschen leben lernen, die einen künstlichen Darmausgang oder eine künstliche Harnableitung, ein sogenanntes Stoma, erhalten. (Quelle: Stuttgarter Zeitung 1996)
• Der Begriff Stoma kommt aus dem Griechischen und bezeichnet den künstlich angelegten Ausgang von Dünn- und Dickdarm oder die künstliche Ableitung aus der Blase. (Quelle: Stuttgarter Zeitung 1996)
• Ähnlich geht es älteren Patienten, die meist wegen einer Darm- oder Blasenkrebserkrankung ein Stoma erhalten. (Quelle: Stuttgarter Zeitung 1996)
• Viele, vor allem die älteren Betroffenen, ziehen sich zurück, wenn sie mit dem Stoma aus dem Krankenhaus entlassen werden, erzählt Werner Knoll vom Landesverband der ILCO (Ileostomie-Colostomie-Urostomie-Vereinigung). (Quelle: Stuttgarter Zeitung 1996)

• The terms ostomy and stoma are general descriptive terms that are often used interchangeably though they have different meanings. An ostomy refers to the surgically created opening in the body for the discharge of body wastes. A stoma is the actual end of the ureter or small or large bowel that can be seen protruding through the abdominal wall. (http://www.uoa.org/ostomy_main.htm)
• If the cancer is more extensive, larger parts of the colon and rectum may need to be removed. Doctors have to create an opening in the skin of the abdomen so that stool can be eliminated from the body. This opening is called a stoma or an ostomy. Because the colon is involved, the opening is called a colostomy....
If kidney function is deteriorating or if drainage of urine through a permanent catheter is not feasible, surgery may be needed to divert the urine to an external opening (ostomy) made in the abdominal wall. (Merck Manual)
• This may involve creation of an artificial opening in the abdomen called an ostomy
• An ostomy is a surgical procedure that creates an artificial opening in the body. This opening is called a stoma (from the Greek word for ‘mouth’).... Children who have ostomies since infancy accept their ostomies as normal.
• the negative body image associated with an external ostomy appliance
• an ostomy, or opening, into the intestine through the abdominal wall
• Ostomy: A surgical procedure in which a new body opening is created. ... Stoma: An artificial opening.
• Ostomy Support Groups are organised all over the country ... you can chat to fellow Ostomates on alt.support.ostomy. ... Yahoo! hosts the UK Ostomy Support chat room
• The Venice, Florida Ostomy Support Group is a support group for people with ostomies, ie, colostomies, ileostomies and urostomies.

Oops, forgot the web examples.

Hope that's all.

AHD4
“u•ros•to•my (yʊ-rŏs'tə-mē)
n., pl. -mies.
Surgical construction of an artificial excretory opening from the urinary tract.”
http://www.answers.com/urostomy&r=67
"Urostomy" does not appear in any of the medical dictionaries that I possess but reference to e.g. “any type urostomy” can be found at the American Urological Association:
http://www.auanet.org/eforms/search.cfm?searc...
“Urostomy Association of Great Britain & Ireland
The Association was formed in 1971 as the Urinary Conduit Association to help people who are about to undergo or have undergone surgery resulting in diversion of the urinary stream. In 1984 the name was changed to the Urostomy Association (UA)”
http://www.uagbi.org/
“Fact Sheet - Urostomy”
http://www.uoa.org/ostomy_facts_urostomy.htm
Roche Leximed:
“Urostoma
künstlich angelegte Öffnung in der Bauchdecke zur Ableitung des Harns entweder über ein Darmstück (z.B. Ileum) oder einen Ureterstumpf, der in die Bauchwand eingenäht wird; v.a. nach operativer Entfernung der Harnblase.”
http://www.tk-online.de/rochelexikon

Dorlands Medical Dictionary:
“nephrostomy (ne•phros•to•my) [nephro- + -stomy] the creation of a fistula leading directly into the pelvis of the kidney.”
http://www.mercksource.com/pp/us/cns/cns_hl_d...
Roche Leximed:
“Nephro|stomie
E: nephrostomy
Fach: Chirurgie
Anlegen einer äußeren Nierenfistel (nach Freilegung u. Inzision, evtl. Punktion), meist am unteren Pol; v.a. bei Harnstauung, infizierter Hydronephrose (vor op. Korrektur), nach Steinentfernung oder Harnleiterresektion. Harnableitung über N.-Katheter (für langfristige oder ständige Nierenfistel T-Rohr oder Ballonkatheter, für kurzfrist. Drainage Gummirohr mit eingeschnittenen Augen); bei Ureterenge zusätzlich Schienenkatheter.”
http://www.tk-online.de/rochelexikon/
Thieme Leximed Medizinisches Wörterbuch, Thieme Verlag 1996:
“Nephrostomie f.urol – nephrostomy”

Fully support sorting out and expanding these entries, especially in view of the recent repeated suggestions of "artificial anus" for various sorts of “ostomy”.

@hm--us: What a great piece of research, many thanks <waving enthusiastically back>.

In answer to one question, “urostomy” covers all ostomies of the urinary tract (“nephrostomy” “ureterostomy” “cystosomy” and “urethrostomy” etc.), while a “nephrostomy" involves the kidney directly.

urostomy [med] – die Urostomie
urostomy [med] – das Urostoma
nephrostomy [med] – die Nephrostomie
ureterostomy [med] – die Ureterostomie
cystostomy [med] – die Zystostomie
cystostomy [med] – das Zystostoma
urethrostomy [med] – die Urethrostomie

Dorlands Medical Dictionary:
“ureterostomy (ure•ter•os•to•my) [uretero- + -stomy] surgical formation of a fistula through which a ureter may discharge its contents.”
http://www.mercksource.com/pp/us/cns/cns_hl_d...
Roche Leximed:
“Uretero|stomie
En: ureterostomy
operative Harnleiter-Haut-Fistel bzw. – i.w.S. – die sie herbeiführende Operation, Ureterokutaneostomie.”
http://www.tk-online.de/rochelexikon/
Thieme Leximed Medizinisches Wörterbuch, Thieme Verlag 1996:
“Ureterostomie f urol ureterostomy”

Dorlands Medical Dictionary:
cystostomy (cys•tos•to•my) [cysto- + -stomy] the formation of an opening into the bladder. Called also vesicostomy
http://www.mercksource.com/pp/us/cns/cns_hl_d...
Zysto|stoma
Syn.: -stomie
En: cystostomy
künstliche Blasenfistel.
http://www.tk-online.de/rochelexikon/
Thieme Leximed Medizinisches Wörterbuch, Thieme Verlag 1996:
Zystostoma nt urol – cystostomy
Zystostomie f urol – cystostomy

Dorlands Medical Dictionary:
“urethrostomy (ure•thros•to•my) [urethro- + -stomy] surgical formation of a permanent opening of the urethra at the perineal surface”
http://www.mercksource.com/pp/us/cns/cns_hl_d...
Roche Leximed:
“Urethro|stomie
En: urethrostomy
auf Zeit oder für Dauer operativ (Urethrotomie) angelegte Harnröhren-Darm-Fistel beim Mann zur Harnableitung; meist Katheterfistel (= „Boutonniere“); v.a. bei angeborenen Harnröhrenfehlbildungen, bei Verletzung des penilen Harnröhrenabschnitts.”
http://www.tk-online.de/rochelexikon/
Thieme Leximed Medizinisches Wörterbuch, Thieme Verlag 1996:
“Urethrostomie f urol urethrostomy"

Continuing down the urinary tract.

urostomy [med] – die Urostomie
urostomy [med] – das Urostoma
nephrostomy [med] – die Nephrostomie
ureterostomy [med] – die Ureterostomie
cystostomy [med] – die Zystostomie
cystostomy [med] – das Zystostoma
urethrostomy [med] – die Urethrostomie

tracheotomy [med] die Tracheotomie - already in LEO
tracheotomy [med] die Tracheotomia

tracheostomy [med] die Tracheostomie
tracheostomy [med] das Tracheostoma

And your question about the difference between tracheotomy and tracheostomy…
(as a basic rule, -otomy means cutting into and -ostomy means fashioning an opening)

"What is a Tracheostomy?
Tracheotomy is a surgical procedure that is usually done in the operating room under general anesthesia. A tracheotomy is an incision into the trachea (windpipe) that forms a temporary or permanent opening which is called a tracheostomy. Sometimes the terms "tracheotomy" and "tracheostomy" are used interchangeably. The opening, or hole, is called a stoma.”
http://www.tracheostomy.com/what.htm

"Tracheostomy is an operative procedure that creates a surgical airway in the cervical trachea. The traditional semantic difference between "-ostomy" and "-otomy" is blurred in this instance because the hole is variably permanent. If a cannula is in place, an unsutured opening heals into a patent stoma within a week. If decannulation is performed (ie, the tracheostomy cannula is removed), the hole closes in a similar amount of time. The cut edges of the tracheal opening can be sutured to the skin with a few absorbable sutures to facilitate cannulation and, if necessary, recannulation; alternatively, a permanent stoma can be created with circumferential sutures. The term tracheostomy is used, by convention, for all these procedures. It is considered synonymous with tracheotomy."
http://www.emedicine.com/ent/topic356.htm

“Tracheo|tomia
Syn.: -tomie
tracheotomy
Eröffnung der Luftröhrenvorderwand (Spaltung oder umschriebene Exzision) im oberen Drittel zwecks Einführung einer Kanüle („Tracheotomiekanüle“) bei Atemnot(gefahr), z.B. bei Larynx-, Trachealstenose oder -verletzung. Erfolgt ober- oder unterhalb des Schilddrüsenisthmus (T. superior oder T. inferior) oder, nach Isthmusspaltung, mit Einkerbung zwischen 3. u. 4. Trachealring (T. media, auch transisthmische T.; geringste Gefahr der Chondritis u. subglottischen Stenose). Kompl.: Druckulkus, Arrosionsblutung, Trachealstenose. S.a. Koniotomie.”

“Tracheostomie
2)
En: tracheostomy
Tracheostoma.”
http://www.tk-online.de/rochelexikon/
“Tracheo|stoma
durch Tracheotomie herbeigeführte Öffnung der Luftröhre nach außen.”
http://www.tk-online.de/rochelexikon/

Thieme Leximed Medizinisches Wörterbuch:
“Tracheotomie f chir. HNO tracheotomy”
“Tracheotomia f. chir HNO tracheotomy”
“Tracheostomie f chir HNO tracheostomy”
“Tracheostoma nt chir HNO tracheostoma, tracheostomy”

I really feel "tracheostomy" should be added since it is used far more commonly than "tracheotomy".

Ich weiß nicht, ob mein Kommentar hier relevant ist, aber "Tracheotomie" und "Tracheostoma" haben ursprünglich und vom Wortstamm her unterschiedliche Bedeutungen.

"Tracheotomie" ist die Operation, d.h. das Aufschneiden der Luftröhre, von griechisch "tome..." = schneiden.

"Tracheostoma" ist die durch den Luftröhrenschnitt entstandene Öffnung, von griechisch "stoma" - Mund.

Bitte nagelt mich nicht auf Einzelheiten zu meinen kaum rudimentär vorhandenen Grischischkenntnissen fest.

Die Unterscheidung der Bedeutungen mag heute zum Teil verwischt werden, im Englischen vielleicht mehr als im Deutschen, aber der Unterschied ist vorhanden und sollte, falls man sich präzise ausdrücken möchte auch beibehalten werden.

tracheotomy [med] die Tracheotomie - already in LEO
tracheotomy [med] die Tracheotomia

tracheostomy [med] die Tracheostomie
tracheostomy [med] das Tracheostoma

tracheotomy [med] die Tracheotomie - already in LEO
tracheotomy [med] die Tracheotomia

tracheostomy [med] die Tracheostomie
tracheostomy [med] das Tracheostoma

@ Karsten
I agree.
The pairs I have suggested above do maintain the difference, even if the general usage today is blurred.

ostomy n. (pl. -ies) Med.
ostomy n. (pl. -ies) Med.

1
an operation that involves
making a permanent artificial
opening in the body.
2
an opening so made.
[The Canadian Oxford Dictionary]

cys·tos·to·my (si stosÆtà m"), n., pl. -mies. Surg.
1.the construction of an artificial opening from the bladder through the abdominal wall, permitting the drainage of urine.
2.the opening so constructed.
[Random House Webster's Unabridged]

Augehend von diesen beiden Quellen gehe ich davon aus, daß sämtliche Wörter auf "-ostomy" einmal den Vorgang (also die Operation) und einmal die gelegte Öffnung bezeichnen können. Im Deutschen mit -ostomie (Operation) und -ostoma (künstl. Öffnung) wiedergegeben. Habe ich das richtig erkannt? Sollte ich auch jeweils noch einen Eintrag "[-ostoma]" [med.] -- "*ostoma" hinzufügen?

Puh, bit daunting to read through all these suggestions. Anyway, I have tried my best, please comment. Maybe someone can even make my list sort of uniform.

tracheotomy [med.] -- die Tracheotomie {al Tracheotomia}

tracheostomy [med.] -- die Tracheostomie
tracheostomy [med.] -- das Tracheostoma

ostomy {i artificial opening, normally referred to as 'stoma'} -- das Stoma
ostomy {i artificial opening, normally referred to as 'stoma'}[med.] -- künstlicher Ausgang
ostomy {i artificial opening for the bowels, normally referred to as 'stoma'}[med.] -- künstlicher Darmausgang

stoma {i artificial opening}[med.] -- das Stoma

colostomy {i operation}[med.] -- die Kolostomie
colostomy {i artificial opening for the colon}[med.] -- das Kolostoma
colostomy {i artificial opening for the colon}[med.] -- künstlicher Dickdarmausgang

ileostomy {i artificial opening for the ileum}[med.] -- künstlicher Dünndarmausgang
ileostomy {i artificial opening for the ileum}[med.] -- das Ileostoma
ileostomy {i operation}[med.] -- die Ileostomie

urostomy {i operation}[med.] -- die Urostomie
urostomy {i artificial opening for the ureter}[med.] -- das Urostoma
urostomy {i artificial opening for the ureter}[med.] -- künstlicher Harnleiterausgang

nephrostomy {i operation}[med.] -- die Nephrostomie
urethrostomy [med.] -- die Urethrostomie
urethrotomy [med.] -- die Urethrotomie {al Urethrotomia}

cystostomy {i operation}[med.] -- die Zystostomie
cystostomy {i artificial opening for the bladder}[med.] -- das Zystostoma

P.S.: statt der Auszeichnung mit {coll.}, wie von hm -- us vorgeschlagen, würde ich einen Kommentar in Klammer bevorzugen, ich weiß nur nicht, ob mein Versuch (s. ostomy) besonders gelungen ist.

@Doris (LEO-Team) >>Im Deutschen mit -ostomie (Operation) und -ostoma (künstl. Öffnung) wiedergegeben. Habe ich das richtig erkannt?<<

Radio Eriwan sagt: Im Prinzip ja, aber...

"-stoma" oder "-stom-" - von griechisch "Stoma" = "der Mund"

"-tom-" - von griechisch "tome" = "der Schnitt"

"-ia" (dt.) und "-ie" (lat.) - die Suffixe bezeichnen beim Substantiv entweder wie hier eine Tätigkeit oder einen krankhaften Zustand.

Also hier zum Beispiel:

Trache-o-stoma =
Luftröhre-(Bindevokal)-Mund =
künstliche Atemöffnung in der Luftröhre

Trache-o-stom-ie =
Luftröhre-(Bindevokal)-Mund-Tätigkeit =
das chirurgische Anlegen eines Tracheostomas

Trache-o-tom-ie =
Luftröhre-(Bindevokal)-Schnitt-Tätigkeit =
Luftröhrenschnitt (auch zur Anlage eines Tracheostomas)

I can't go back through all this again right at the moment, but I'm afraid I really don't like 'normally referred to as' at all. The whole point is that in English it's NOT normally referred to as a stoma, but as an ostomy. Stoma is an unusual, uncommon, technical word, used only by doctors if then; ostomy is the normal word, used AFAIK by both patients and doctors.

In general, I think over-explaining is unnecessary (the old LEO-is-not-an-encyclopedia thing), and in fact, it's distinctly unsafe if you're not sure you're giving the right explanation. As long as you know that there are some contexts in which the pair is right, you can leave it to the user to decide which translation is better for which context. Just knowing that there are several choices should be tip-off enough.

Ich kenne es so wie Mark beschrieben hat: -tomie bezeichnet die chirugische Öffnung (Laparotomie, Thorakotomie, Tracheotomie, Tympanotomie etc.), das Stoma ist die künstliche Öffnung die dann entsteht, und die im einzelnen z.B. als Tracheostoma, Kolostoma, (oder -stomie) bezeichnet wird.

Also need some time to read, mark, learn and inwardly digest this lot :-)
Immediate responses
Agree with hm' s comment about NOT 'normally referred to as stoma' ...

Also your suggestions
urostomy {i artificial opening for the ureter}[med.] -- das Urostoma
urostomy {i artificial opening for the ureter}[med.] -- künstlicher Harnleiterausgang
are not quite right - "urostomy" is an "ostomy" of anywhere in the urinary tract, not just the ureter

urostomy {i artificial opening for the urinary tract}[med.] -- das Urostoma
urostomy {i artificial opening for the urinary tract}[med.] -- künstliche Harnableitung ??
ureterostomy {i artificial opening for the ureter}[med.] -- das Ureterostoma
ureterostomy {i artificial opening for the ureter}[med.] -- künstlicher Harnleiterausgang

I will also have a go at pulling it all together if you like ...

Thanks all for your replies.
I didn't feel confident about my explanation in brackets so let's just forget it.
What I would like to add, however, is the distinction between "operation" and the "result of the operation" so as to limit the confusion for the person that needs to choose the right German translation.

@Marianne: it would be great if you could "pull it all together" but I'm going away for two weeks on Sunday so won't work on these entries again before I come back :-)

@Doris
That gives me some breathing space to get my act in order then :-)

Have a great holiday, if holiday it be ...