A colostomy may be formed from any section of the large bowel. Its position along the colon will dictate the output and consistency of the faeces. Therefore, an understanding of the relevant anatomy and physiology is essential to fully care for stoma patients.

The most common site for a colostomy is on the sigmoid colon. This will produce a semi‐solid or formed stool and is generally positioned in the left iliac fossa and is flush to the skin (Boyles and Hunt [33]). Stomas formed higher up along the colon will produce a slightly more liquid stool. A colostomy tends to be active on average two or three times per day, but this can vary between individuals.

Colostomies can either be permanent or temporary (Figure 6.26). Permanent (end) (Figure 6.27) colostomies are often formed following removal of rectal cancers, as in abdominoperineal resections of the rectum, whereas temporary (loop) colostomies (Figure 6.28) may be formed to divert the faecal output, to allow healing of a surgical join (anastomosis) or repair, or to relieve an obstruction or bowel injury (Rostas [218]). Temporary stomas have increased in prevalence over the years and now there are more temporary ileostomies and colostomies than permanent ones (Lim et al. [131]).

As is evident from Figures 6.27 and 6.34, end and loop colostomies are very different in appearance. An end colostomy tends to be flush to the skin and sutured to the abdominal wall and consists of an end‐section of bowel, whereas a loop colostomy is larger. During the perioperative period, a loop colostomy is supported by a stoma bridge or rod (see Figure 6.28). This is placed under the section of bowel and generally left in place for approximately 5 days following surgery and then removed (Whiteley et al. [245]).

Ileostomies are formed when a section of ileum is brought out onto the abdominal wall. This is generally positioned at the terminal end of the ileum on the right iliac fossa, but it can be anywhere along the ileum (Black [28]). Consequently, the output tends to be a looser, more liquid stool, as waste is eliminated before the water is absorbed from the large bowel (colon). Due to the more alkaline, abrasive nature of the stool at this stage, a spout is formed with this type of stoma. The ileum is everted to form a spout, which allows the effluent to drain into an appliance without coming into contact with the peristomal skin (Figure 6.29). This prevents skin breakdown and allows for better management (Burch [39]). The average output from an ileostomy is 200–600 mL per day.

Ileostomies can also be either permanent (end) (Figure 6.29) or temporary (loop). Permanent ileostomies are often formed following total colectomies (removal of the entire colon). Loop ileostomies are increasingly common and are often formed to allow healing of a surgical join (anastomosis) or an ileoanal pouch (Black [27]). These are sometimes held in place by a stoma bridge or rod. See Procedure guideline 6.28: Stoma bridge or rod removal for more information on bridge and rod care and removal.

An ileal conduit is the most common form of urostomy; the colon (colonic conduit) may also be used. Urostomy comes from the Greek words uros, meaning urine, and stoma, meaning mouth or opening (Nazarko [156]).

A section of bowel is isolated, along with its mesentery vessels, and the remaining ends of the bowel are anastomosed to restore continuity. The isolated section is mobilized, the proximal end is closed and the ureters, once resected from the bladder, are implanted at this end. The distal end is brought out onto the surface of the abdominal wall and everted to form a spout (Figure 6.29), as in an ileostomy (Leach [124]). Urine from a urostomy will contain mucus from the bowel used in its construction (Geng et al. [84], Leach [124]).

Some patients who are obese may have a Turnbull's loop ileal conduit formed. The distal and proximal ends of the loop can expel urine. There is an improved blood supply to the distal portion of the conduit by delivering mesenteric blood supply to this area. Selected obese patients and those in which the tension to the distal end of the stoma may contribute to ischaemia and stomal stenosis are given this type of ileal conduit. These patients may have a stoma rod in addition to ureteric stents in situ.

Stents are removed following advice from the urological surgeon. This can be done after 7 days; however, the timing of removal is dependent on whether the patient has undergone previous radiotherapy, or has one kidney or other underlying renal issues, in which case the amount of time the stents are in situ may be longer. The stoma bridge is removed after approximately 5 days.

Ureteric stents protect the anastomosis at the ureteroileal junction by allowing healing, and preventing strictures and leakage (Leach [124]). They also ensure the kidneys can drain urine freely and prevent upper urinary tract obstruction caused by compression due to post‐operative oedema. The stents need to be monitored; although they facilitate the flow of urine, they may become obstructed due to bleeding, calculi or sediment (for example). Obstruction can result in hydronephrosis and kidney damage. The stent is a foreign body in the urinary tract and can increase the risk of a urinary tract infection. A two‐piece bag system aids stoma management immediately post‐operatively, while the stents are in situ, and allows the healthcare professional to check the stents. The stents should be checked daily for drainage. If they are not draining, the urology team should be informed as they may need to be flushed (refer to Procedure guideline 6.15: Flushing externalized ureteric stents) (Leach [124]). The patient should have adaptors for the stents from the time of surgery to assist with flushing.

The Carter double‐barrelled wet colostomy – commonly known as a Carter stoma or DBWC – is a specialist technique offered to patients having a total pelvic exenteration in some institutions. The procedure involves performing bipolar colostomy, with the section and sutured closure of the distal end of the colon at about 10–15 cm distal to the stoma, and implantation of ureters into the formed colon conduit. After the intervention, a urine reservoir, which is formed distal to the stoma, empties out freely without faecal contact (Pavlov et al. [191]) (Figure 6.30). The main advantage to the patient is managing just one stoma. A specialist bag is required to manage the mixed output (Figure 6.31).