Nicely done! (technically, Skeletal Troll comes from Summon Undead, a Spell Compendium spell of the same level as Summon Monster, but if I were DM I could easily be convinced to amalgamate them into one spell—they’re pretty much identical except for the creature summoned, after all)
Shame about the monk, though. If it was a vampire that took him/her out instead, at least he/she’d maybe come back with a cool template. Honestly, monks have it pretty stacked against them, so I’m impressed they survived all the way to fight a CR 15 monster. Well done!