Stoma Site Selection
I have Crohn’s disease and need to have surgery. My surgeon says I will need to have a stoma. A friend said I should get the spot selected for the stoma before surgery. What does this mean?
Your friend is referring to stoma site marking, a process that occurs prior to surgery in which a specific location for the stoma is selected on your abdomen. Selecting the site prior to surgery, rather than exactly at the time of surgery, will help to ensure that is in a position that will facilitate self-care and secure pouching. Several factors are taken into consideration when the site is chosen; these will be discussed below. Stoma site selection should be done by an Enterostomal Therapy Nurse (ET) and/or by the surgeon responsible for your surgery.
Site selection is initially determined by the type of stoma that you are going to have; stomas tend to be placed in the lower half of the abdomen, generally below the level of the umbilicus, but above the level of the pubic hair. Usually, ileostomies (stomas made from the last portion of the small intestine) are placed in the right lower quadrant, while people who require colostomies (stomas made from part of the large intestine) have their stomas placed in the left lower quadrant of the abdomen. On occasion, stomas may be placed in atypical locations (such as the opposite side) due to old scars, hernias or other factors that may make their usual location impossible to use. Stomas tend not to be placed in the upper abdominal quadrants (above the level of the umbilicus, below the lower level of the ribs), but in certain circumstances it may be required. For patients who are having urinary diversions, such as an ileal conduit, the stoma should be sited in the right lower quadrant. Your ET and surgeon will discuss the placement with you.
Stomas should also be sited within the margins of a specific abdominal muscle called the rectus. This muscle runs vertically and is in the front of the abdomen. It is believed that placing the stoma within the margins of this muscle will help to prevent possible complications, such as parastomal hernias. While a recent review article1, questions if this notion is, in fact, accurate, stoma placement should remain within the rectus muscle until definitive studies demonstrate that placement outside of the rectus does not result in stomal problems.
Ideally, appliances for stomas require a flat surface on the abdomen to allow for appliance adhesion. At a minimum, a flat surface that extends approximately 2-3 inches (5-8 centimetres) circumferentially from the base of the stoma will help to ensure a secure seal. As a result, certain abdominal contours should be avoided to allow for this seal. Any deep creases, skin folds and old scars may interfere with both visualization of the stoma and appliance adhesion. Deep creases are best assessed when you are sitting, or bending forward, and these positions will accentuate any folds or creases that may be problematic.
Stomas should also be placed on the upper aspect of a skin fold. People who have obese abdomens, who have protuberant abdomens, or who have rounded skin folds should have the stoma placed on the upper aspect of the fold or protuberance as this will help to ensure that the stoma is visible for routine care. If the stoma is placed at the apex or the underside of a fold or protuberance, it may fall away from the field of vision, making self-care difficult. Regardless of whether you have an obese or protuberant abdomen, the stoma should be within your visual field: you must be able to see it when you are either sitting or standing to be able to do routine care.
Stomas should also be away from the belt line, either above or below the level at which you wear your belt. Stomas which are placed right on the belt line risk potential trauma (bruising, bleeding) from the pressure of the belt. Ideally, ETs would like to place all stomas below the belt line, as this would ensure concealment of the pouch under clothes. However, placement below this level is often not possible. Placement below the belt line is usually problematic for men, as men tend to wear pants/belts below the natural waist-line. In these situations, stomas placed below the belt line will often be too close to the bony prominences (pelvic bone) which may contribute to poor appliance seals, or may be away from the visual field. Equally, recent fashion styles of low rise pants and skirts also make concealment and placement below the belt-line difficult, if not impossible. Alternative options include higher rise pants or skirts, or the use of suspenders rather than belts to support trousers.
Other factors to consider include your activity level: individuals who are active may want to have the option of wearing a belt that attaches to the ostomy appliance. These belts can provide additional support to your appliance during activities, adding another level of security. Ostomy belts work best when they rest along your natural waist-line, rather than above or below your waist-line. If the belt pulls at your pouch from a dramatic angle, rather than directly perpendicular to the belt tabs, it may cause the pouch to ride or shift, making it less secure. If you are wheelchair dependent, you should have your stoma site marked while sitting in the chair, with all support devices such as seat belts in place. Your seating in the chair will often demonstrate ideal placement of the stoma, avoiding potential traumas from support devices. The stoma may also be placed higher on the abdomen to make self-care and appliance emptying easier.
When the stoma site is being marked, you will initially be asked to lie flat on your back on the examining table. Your abdomen will be inspected for any obvious scars or other contours that may need to be avoided. The ET will ask you to briefly raise your head; this allows him/her to identify the outer margin of your rectus muscle by feeling for a firm ridge on your abdomen. The ET will then identify an area with the appropriate abdominal quadrant where the stoma may be placed. Some ETs like to use an actual stoma flange for sitting, and may stick this onto your abdomen during the marking. The flange will be removed before you go home. Other ETs may use clear plastic rings to help with sitting. You will then be asked to sit; this helps to accentuate any creases and folds. The ET may then adjust the placement of the flange/ring based on identified contours. She/he may also ask you to lean forward, twist and raise your leg. All of these movements are to help identify the best location for your stoma, avoiding any areas of concern. You may also be asked to put your pants/skirt on, so that the placement can be seen in relation to your belt line. Again, further adjustments may be required for the site based on the belt line. Once the best location has been chosen, it will be marked with a surgical marker/felt pen, and covered with a plastic clear film dressing. The dressing is required to protect the marking and to prevent it from washing off during routine bathing. It is important that you ensure that the site remains visible, as it will be used by the surgeon to place your stoma.
Stoma site marking is a complex process, but is very important for ensuring safe and secure pouching for your stoma. You should contact your ET and/or surgeon to discuss this procedure prior to your surgery.
1. (Gray, M. et al. (2005) “What Treatments Are Effective for the Management of Peristomal Hernia?” Journal of Wound, Ostomy and Continence Nursing, 32:2, pp 87-92.