Effect of Chewing Gum on Postoperative Bowel Function Following Upper GI Tract Cancer Surgery

Every surgical procedure results in a temporary paralysis of bowel function. This condition is named postoperative ileus (POI) and it is characterized by absence of intestine motility, accumulation of gas and fluid inside the intestines and absence of flatus and defecation. It results in nausea, vomiting, abdominal distension, pain and lowered tolerance towards intake of fluid and solid foods. POI is the organism's reaction to the surgical trauma and it is most often the single most important factor determining the length of patient admission. Prolonged POI can also result in medical complications.

The length of POI following elective abdominal surgery is most often 3 to 6 days. Gradually during this period the intestines regain their normal behavioral pattern. The colon is the last segment to regain its motility which decides the patient's wellbeing. Therefore most investigations of POI measure time from surgery to first flatus or defecation.

The cause of POI is found in the surgical trauma. When the abdominal wall and the peritoneum are penetrated and the intestines exposed and handled, the immune system is activated. The immune system creates an inflammatory response that inhibits the local neural pathways in the intestines. The size of the immune response is related to the size of the surgical procedure and the length of POI. Together with the overall hormonal surgical stress response the inflammatory response creates a shift in the autonomous nervous system towards sympathetic domination. This further inhibits bowel activity.

The intake of food activates parasympathetic activity and promotes bowel activity. Early food intake following abdominal surgery, however, is often ill received by the patients hence the above mentioned symptoms of POI. The early food intake can also worsen complications following surgery such as anastomotic leakage. This is most pronounced with anastomoses on the esophagus and stomach. Therefore abstinence from food intake is often recommended in the immediate postoperative period.

Chewing of chewing gum following surgery can be perceived as placebo intake of food because it also activates the parasympathetic nervous system and under normal conditions the cephalic part of the digestion. Gum chewing does not, however, result in worsening of potential surgical complications and it is generally well tolerated by the patients. Postoperative gum chewing has been investigated and found effect full in the shape of reduced POI following colorectal surgery, abdominal surgery on the aorta, bladder surgery, and caesarian section.