For much of the surgery sequence, Michael Dorn's stunt double Al Foster stood in as the Klingon exo-backbone was glimpsed for the first time.
	The motor assist bands and the drugs inoprovaline ("Transfigurations") and cordrazine ("Shades of Gray") were all nods to continuity.
	A gravitic mine left over from the Cardassian War that destroys the U.S.S. Denver was referred to earlier in the Kobayashi Maru scene in Star Trek II.
	The producers allowed LeVar Burton to try out the beard look but felt it didn't work.

If you have some more behind the scenes information, send it in.