Reference to the "Hartmann operation" for diverticulitis of the sigmoid colon is found with increasing frequency in the current medical literature. In principle, this operation consists of the removal of a segment of colon containing an acutely inflamed area of diverticulitis, with or without perforation or fistula. The end of the proximal colon is brought out as a colostomy. The end of the distal colon is oversewn above the pelvic peritoneum and dropped back into the abdomen. The incision is then closed. Several months later, after reaction to the disease and the operation has subsided, anastomosis of the ends of healthy colon above and below is carried out as the second stage.
Proponents of this approach cite a mortality significantly lower than that after primary resection and anastomosis since the suture line made in the absence of acute inflammation is more secure than one made in the presence of peritonitis
Sanderson ER. Henri Hartmann and the Hartmann Operation. Arch Surg. 1980;115(6):792-793. doi:10.1001/archsurg.1980.01380060088026