Colonic diverticulitis refers to a condition where a small part of the colon wall pouches outward (diverticulum) and gets infected. If the infection is localised (simple diverticulitis), you can be treated with antibiotics alone. The colon can heal well in most cases of simple diverticulitis.
However, if the diverticulitis is left untreated or if it does not heal with antibiotics, you may form an abscess around the colon. The abscess can burst and spill colonic content into the abdomen if left untreated. The abscess can also erode into the surrounding tissue. If that happens, an abnormal connection can form between the colon and the surrounding tissue. One example is when the abscess erodes into the urinary bladder causing the patient to notice gas or faeces when he/she passes urine. These patterns of diverticulitis are called complex/complicated diverticulitis. Complicated diverticulitis requires more aggressive antibiotics and surgery is inevitable.
In complicated diverticulitis, the aim of surgery is to remove the infection and prevent further infection. The segment of infected colon is excised and the colon is usually joined back together whenever possible. You may need to wear a stoma bag but that will usually be temporary.
