These obstetric findings have prompted a limited number of studies investigating airway changes in patients undergoing surgical procedures. This study will focus on surgeries in the prone and Trendelenburg positions, as they would intuitively predispose patients to edema and fluid retention in the head and neck. MMS increased in 78% of patients, with 29% increasing by two or more classes in patients undergoing lumbar spine surgery in the prone position. Furthermore, although laparoscopic surgery has been shown to increase lung and chest wall mechanical impedance, which leads to increases in abdominal and intrathoracic pressure, as well as an increase in central venous pressure with subsequent increases in intraocular pressure, no studies have been performed to specifically track resultant airway changes. Lastly, to investigators' knowledge no studies have investigated the postoperative resolution of airway changes after either type of procedure.