An injured mesentery can bleed profusely after an open or a closed injury, and bleeding has little tendency to stop. The mesentery is usually injured near its relatively fixed top and bottom ends. When you examine it you may find a tear or a haematoma.
Short tears are not serious, especially if they are perpendicular to the patient’s gut, as in G, Fig. 66-15. The danger in sewing a tear is that you may include the vessels supplying the gut in your sutures, and so impair its blood supply. Vessels approach the gut from the mesentery. Because there is very little circulation along the length of the gut, tears close to its mesenteric border and parallel to it are particularly dangerous.
Some haematomas limit themselves, and don’t need treatment. Others expand, compress the vessels in the mesentery, and impair the blood supply to the gut. The difficulty is knowing what they are going to do. Opening a haematoma and trying to find the bleeding vessel increases blood loss, and risks damaging the vessel. Some surgeons leave haematomas alone. Others explore them to find the bleeding vessels, particularly if a haematoma is expanding. If the blood supply to a patient’s gut is impaired, you will have to explore the bleeding vessel and, if necessary, resect his gut.