<s>
Endoscopic	B-Algorithm
stenting	I-Algorithm
is	O
a	O
medical	O
procedure	O
by	O
which	O
a	O
stent	O
,	O
a	O
hollow	O
device	O
designed	O
to	O
prevent	O
constriction	O
or	O
collapse	O
of	O
a	O
tubular	O
organ	O
,	O
is	O
inserted	O
by	O
endoscopy	B-Application
.	O
</s>
<s>
There	O
are	O
various	O
types	O
of	O
endoscopic	B-Application
stents	O
:	O
plastic	O
stents	O
,	O
uncovered	O
self-expandable	O
metallic	O
stents	O
,	O
partially	O
covered	O
self-expandable	O
metallic	O
stents	O
,	O
and	O
fully	O
covered	O
self-expandable	O
metallic	O
stents	O
.	O
</s>
<s>
A	O
stent	O
may	O
be	O
inserted	O
into	O
the	O
common	O
bile	O
duct	O
during	O
an	O
endoscopic	B-Algorithm
retrograde	I-Algorithm
cholangiopancreatography	I-Algorithm
,	O
especially	O
if	O
gallstone	O
removal	O
is	O
deemed	O
too	O
risky	O
.	O
</s>
