De or het bandletsel?

The correct Dutch article is:

het bandletsel

Rule Words ending in -sel: usually het. See the rule

How to use bandletsel

the bandletselhet bandletsel
this bandletseldit bandletsel
that bandletseldat bandletsel
our bandletselons bandletsel
your bandletseljouw bandletsel
every bandletselelk bandletsel
which bandletsel?welk bandletsel?
a big bandletsel / the big bandletseleen groot bandletsel, het grote bandletsel

Dutch words ending in bandletsel

kruisbandletsel

In compound words, the last part decides the article. See the rule