I regularly give ketamine and prop infusions with most of my ortho/LE spinal cases. I usually give 2 of versed for the spinal, when they lay down I give 0.2 of glyco with the FM on, start the prop infusion at around 70 mcg/kg/min, bolus 20-30 of propofol with some lido. Then give 10-20 of ketamine with that. I give around 10mg of ketamine every 45 minutes after that unless procedure is going to stop in less than 30 minutes. Works really well and patients are happy. I also don't use pillows during these MACs, I get a warm blanket instead and make sure their neck is extended properly. All of the pillows seem to flex the patient's neck a little bit.
I also do this regimen with a little touch of fentanyl here and there for cases where the surgeon is using local like carpal tunnel releases.