66.15 Injuries of the rectum

A patient’s rectum can be harmed by injuries which reach it from his abdomen or from his buttock. An abdominal wound of the rectum inevitably involves the peritoneum. A buttock wound may involve only his perirectal tissues, or it may enter his peritoneal cavity. His bladder, his urethra, his pelvis, his sacrum, and sometimes even the lower end of his subarachnoid space can be injured at the same time. The main danger is that faeces will leak into the tissue round his rectum and infect it, perhaps fatally.

You cannot bring wounds of a patient’s rectum and rectosigmoid outside his abdominal wall as you can elsewhere in his colon. So aim to: (1) Divert faeces from his rectum by doing a diversionary colostomy above it. This is much safer than merely inserting a large rectal tube. (2) Empty his gut beyond the colostomy. (3) Drain the wound.

The main distinction is between wounds which involve his peritoneum, and those which do not.

Figure 66.22: MORE METHODS for injuries of the colon. A, a wound of the transverse colon has been exteriorized on a loop colostomy. B, the vascular supply of the colon.

Intraperitoneal wounds should be managed like wounds of the distal colon. Make a left iliac colostomy, close the rectal wound, and drain it.

Extraperitoneal wounds make an opening from a patient’s rectum into the tissues round it below the reflection of the peritoneum. There are problems: (1) Diagnosis can be difficult, as in the patient JANE described below. (2) Other structures, especially the bladder and the pelvis, are often injured too. (3) The rectum is difficult to expose from below, so expose it from above, and make a drainage incision down from above, into the peritoneum.

JANE (5) fell from a tree on to a dead branch. Later, she complained of vague tower abdominal pain. There was a little blood in her rectum. She was examined under anaesthesia. A probe entered a wound in her rectal wall and tracked far upwards. Exploration showed that a twig had passed behind her peritoneum lateral to her rectum, in front of her right common iliac vessels, avoiding her right ureter, and up alongside her inferior vena cava as high as her right kidney. Fortunately, no vital organs were damaged. A temporary defunctioning colostomy was done and she recovered. JAKE (24), a performer in a disco bar, jumped in the air and fell on his microphone stand, injuring his perineum. Accompanied by much singing, he was brought irr laughing by his friends. His fresh minor looking perineal wound was toileted and closed by immediate rimary suture. Although he had no abdominal signs, the cautious house officer admitted him. The next morning his pulse rate had a risen (a very important sign). Later in the day he became very ill with a high fever and signs suggesting peritonitis in his lower abdomen. Laparotomy showed a 10 cm wound in his perineum. This led to an area of severe cellulitis, but had not injured any viscera. Large doses of broad spectrum antibiotics cured him. LESSONS: (1) Wounds in some parts of the body can be closed, if you see them early enough. In other areas, including the perineum, this is very dangerous. (2) Wounds may be deeper than they seem, and need radical toileting.