Sufentanil Infusion vs Intravenous Methadone for Postoperative Analgesia Following Head and Neck Dissection With Free Flap or Rotational Reconstruction

1\. Intravenous sufentanil starting at a dose of 0.5 mcg/kg/min hr ideal body weight (IBW) at the beginning of the case, prior to surgical incision, with a discontinuation of the infusion when the surgical microscope is removed from the patient field and the closure of the incision(s) begins. (n=64)

2\. Intravenous methadone of 0.2 mg/kg IBW up to a maximum dose of 20mg, rounded to the nearest milligram. The methadone will be given at the beginning of the case, prior to surgical incision. n=64)