This is a randomized double blinded non-inferiority study comparing the duration of pain
relief when patients receive one of three doses of spinal morphine. Enrolled patients will be
randomly assigned to receive either 50 mcg, 150 mcg, or 250 mcg. All patients will receive
standardized postoperative care, including multimodal analgesia. The primary outcome will be
the time until the patient requests additional opioid pain medications.