Stomach and Small Bowel Injuries
These types of injuries are more common in penetrating than in blunt trauma to the abdomen. In gunshot wounds, the incidence of GI injury is 80 percent or more. This means that surgery should be done on every gunshot wound to the abdomen. Stab wounds result in fewer GI injuries but many still require surgical exploration. Blunt trauma injuries to the stomach and small bowel are the third most common type of injury in blunt trauma. The key to treating these types of injuries successfully is to do surgery as soon as possible, before infection has had a chance to spread inside the abdomen.
The stomach is located in the left upper quadrant of the abdomen and, when it is empty, is up inside the chest cavity some more so it is protected by the breastplate and ribs. There are two big arteries that supply the stomach, the right and left gastric arteries.
The stomach is relatively free of bacteria because of its acidity. With the use of antacids, however, there can be an increase in bacteria in the stomach, which can cause infection when the stomach is disrupted. The small intestine is not very protected and is at an increased increase of injury.
Most gastric injuries come from pedestrian/motor vehicle accidents or during high speed crashes. This is especially true if the person has a full stomach or has the wrong positioning of the seat belt. Most injuries from the front of the stomach and can involve cuts in the stomach or perforations of the stomach wall. There are often other injuries along with the stomach injury, which is why there is such a high mortality rate in stomach perforations.
Small bowel injuries come from blunt abdominal trauma and are uncommon. They come from motor vehicle accidents as well as falls and bicycle accidents. The bowel can be crushed against the spine or can be sheared from the rest of the connection points during rapid decoration injuries. Injuries to the small bowel are more common when the seat belt has not been used properly. Airbags somewhat protect a person from a seatbelt injury.
About twenty percent of people with small bowel injuries have no other injury in the abdomen but the remainder do. This means that, if a patient is having surgery for a rupture of the intestine, they should have a full investigation for other injuries to the abdomen.
Sometimes the blood vessels to the small bowel are damaged, causing a lack of circulation to the bowel so that, weeks later, the person has narrowing of the bowel and a bowel blockage.
Diagnosis of Bowel Trauma
An accurate history of the traumatic event can help tell if there is a likelihood of a stomach or bowel injury. Knife wounds or gunshot wounds have a high likelihood of having some kind of stomach or bowel rupture. A laparotomy should be done in situations such as handle bar injuries, blows to the abdomen, and kicks by a horse or a seatbelt sign (which is abrasions of the chest and abdomen as a result of the seatbelt acting against the abdomen and chest).
Patients with a stomach injury usually have signs of irritation because of the acid that is in the stomach. There can be air found outside the stomach on a plain film x-ray and a nasogastric tube usually comes back showing blood in the fluid. Injuries to the small bowel take longer to show up because the fluid content of the small bowel is not acidic. The surgeon can look for a seatbelt sign or abdominal tenderness as ways to suggest that a small bowel injury has occurred.
Laboratory testing such as a white blood cell count, hematocrit and amylase level can help identify small bowel injuries and gastric injuries. In patients who are being treated without surgery, changes in these lab values can help decide if surgery is necessary.
A peritoneal lavage can show elevated white blood cell counts in situations of bowel rupture. Blood can also be seen in the lavage fluid. The focused abdominal sonography for trauma or FAST test has been used to detect small bowel injuries and gastric injuries but it isn’t a very sensitive teste because there often isn’t a lot of bleeding. This makes the FAST test somewhat unreliable in testing for small bowel and stomach injuries.
The CT scan can be abnormal with rupture of the small bowel or stomach. There can be dye coming out of a hole or rupture of a hollow organ like the small bowel when the dye is swallowed. Air can be seen in the area outside of the gut on CT scan. Bleeding or blood clot in the bowel wall can be seen. There can be free fluid seen on CT scan in the absence of an injury to a solid organ that can help identify the possibility of a hollow organ injury. Sometimes the CT scan is negative but the patient with a high risk injury should be observed just in case the CT scan was wrong and further evidence of a ruptured bowel shows up.
Diagnostic laparoscopy can be helpful in avoiding opening up the patient altogether to look for injuries to the hollow organs. In some cases, small tears can be repaired using laparoscopy, thus avoiding open surgery. If a good laparoscopy is used, it can detect most hollow organ injuries without missing anything. If an in intestinal injury is noted, then the laparoscopy can be stopped and open surgery done to repair the injury.
Surgery to Repair a Hollow Organ Injury
A midline excision is the most often approach for repairing hollow organ injuries. The entire abdomen can be exposed and the gut can be removed from the abdominal cavity and thoroughly assessed for rupture or holes. After control of hemorrhage, the stomach and bowel can be fully assessed for injury.
The stomach can be more difficult to assess because of its attachment to other organized. It must be mobilized in order to see all parts of the stomach. If a hole in the front of the stomach is noted, exploration should be undertaken to look for another hole, such as with an exit wound. If such a wound is not found, the stomach can be submerged in saline and air bubbled into the stomach. If bubbles show up in the saline, a hole exists somewhere in the abdomen.
If the diaphragm is ruptured as well as the stomach, bacteria can get up inside the chest cavity, causing a chest cavity infection. The diaphragm must be closed after closure of the stomach injury. A chest tube may be required in order to drain the chest cavity of infection.
In small bowel injuries, the entire bowel is removed from the abdomen and carefully evaluated centimeter by centimeter for injuries. If there is active bleeding, the bleeding spots should be clamped off and the bleeding vessels secured by suturing them. Tears in the bowel are also closed carefully. Complete transection of the bowel is treated by removing injured bowel and reattaching the healthy ends of the bowel.
Patients who have significant bleeding in surgery can suffer from hypothermia, bleeding disorders and excessive acid in the bloodstream. In such cases, damage control with abdominal packing can be done to control bleeding before a definitive repair can be undertaken. If a large part of the bowel is damaged, this part of the bowel must be removed so that healthy ends can be reconnected.
Antibiotics are usually given for 24 hours after surgery to prevent surgical infection. A nasogastric tube is used to decompress the stomach contents during healing. It is continued until the bowel begins to be active again. Nutritional support with parenteral nutrition can be given to those people who were not very well nourished prior to the injury. Some patients can tolerate careful feeding through the nasogastric tube, while others need nutrition through an IV.
Complications after gastric or small bowel surgery include intra-abdominal infections and sepsis. An abscess can form inside the abdomen in some cases. These are more common if the colon is injured or if there is blunt trauma to the abdomen. A delay in repair can increase the risk of infection.
Bleeding complications can result in bleeding into the bowel itself or into the abdominal cavity. Bleeding can come from the area of repair that wasn’t seen at the time of surgery. CT scan can show areas of leakage at the site of injury. There can then be another surgery or a needle can be inserted through the skin to drain areas of infection or bleeding.
Small bowel obstruction can also occur after repairing a small bowel injury. This can be the result of scar tissue formation in the intestine that block the passage of stool.
Malabsorption can also happen if a large amount of small intestine needed to be removed. These patients can get B12 deficiency and deficiencies of other nutrients. These patients can suffer from short bowel syndrome. Changes in the remaining bowel can occur over months and years that can improve absorption of nutrients. At least three feet of small intestine are necessary to prevent diarrhea in patients who have had small bowel removed.