Hebrew to English Medical Medical (general)

A patient underwent surgery (PCNL) to remove kidney stones

In the hospitalization report there are two comments. One says that after surgery he was weaned off of the nephrostom (נגמל מנפרוסטום).

In the second one it says that a few years later he had a hematuria in the שקית הסטומה

In the first comment, are they saying that he was weaned off of a nephrostomy bag, collecting fluid from the kidney? Is that something one weans off of? Or does נפרוסטום refer to something else?

And in the second one, does the שקית הסטומה also refer to a nephrostomy bag, or something else?

Thanks