[clamboat]

I remember reading that leeches are still used in some eye surgeries, some plastic surgeries. The Brits stuck in prison work camps in Burma used them to eat away gangrene.

I don't think that is technically correct. They may have used leeches, but not because the leeches would remove dead gangrenous tissue, but because the leeches would aid blood circulation, thus preventing gangrene (with a lot of luck). Leeches, like mosquitoes, can locally disable clotting and ensure a continuous trickle of blood from a wound.

[free me]

Correct. It is maggots that are/were used to treat gangrene.

[blackdog]

When reattatching a limb, leaches are used to keep blood flowing. Leaches also produce a natural localized anti-clotting agent at the attatchment site.

[StJulian Perlmutter]

...remove dead gangrenous tissue,...

They use maggots to eat away dead flesh (no, really)....

[bvw]

Yes ... that helps recollection, I was partially right -- they would have men with the gangrene affected legs stand in the river where fish would nibble the gangrene away and then they used leeches to help restore the circulation. History Channel show is where I saw it.