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Pre-Cut Ostomy Systems

Pre-Cut Ostomy Systems

A pre-cut ostomy system refers to a pouch with a cut-out opening already in place, designed to fit the size of the stoma. This system is ideal for patients with a round stoma shape and are available in two types. The flat pouching system is convenient for patients with stomas that protrude outwards at least an inch. The convex pouching system projects towards the stoma and is ideal for smaller, flatter or inverted stoma shapes.

Comparison Between Diverse Ostomy Systems

“To understand how a pre-cut works and its advantages, one must first understand the existent variety of ostomy systems. “A flat pouching system lies flat on the skin around the stoma. A convex pouching system is different because a skin barrier, faceplate, or ring curves outward against the skin. The outward curve presses down on the skin and causes a person’s stoma to stick out more and better empty into the pouching system. […]

What are the different types of convex products?

  • Cut-to-fit convex: This is a one- or two-piece pouching system that allows you to cut the opening in the skin barrier to fit your stoma. This is especially recommended if your stoma is not round.
  • Precut convex: This is a one- or two-piece pouching system that has various-sized openings in the skin barrier.
  • Convex insert: These presized plastic rings are for use in the flange of a flat two-piece pouching system.
  • Barrier strips/rings: These products can be molded to different shapes or sizes.
  • Custom-made convex product: A product with built-in convexity that is made for you by a special company.
  • Faceplate: This is a reusable product with built-in convexity.
  • Ostomy belts and binders: These products may be used to give you extra support.”1

Precut Convex is one of the most fitting ostomy systems to avoid leakage. “One of the guiding principles of ostomy care is to establish and maintain a secure and predictable seal. Products that incorporate convexity are often considered an important tool for achieving this goal. Convexity is defined as a curvature on the skin side of the barrier or accessory. Convex products are frequently cited as the preferred means to manage flat or retracted stomas and to compensate for irregular peristomal planes such as creases or folds. Although a variety of convex products are available with different depths and shapes, there is little supporting evidence to guide their selection and use. The origins of convex product development are not known. Limitations in early ostomy product availability and the need to cope with poorly constructed stomas or irregular body contours were historically addressed by creative use of pastes, belts, rings, and medical adhesives.”2

Measuring the Stoma

“The appropriate pouch system must be selected and fitted to the stoma. Patients with flat, firm abdomens may use wither flexible (bordered with paper tape) or non-flexible (full skin barrier wafer) pouch systems. A firm abdomen with lateral creases or folds requires a flexible system. Patients with deep creases, flabby abdomens, a retracted stoma, or a stoma that is flush or concave to the abdominal surface benefit from a convex appliance with a stoma belt. This type of system presses into the skin around the stoma, causing the stoma to protrude. This protrusion helps tighten the skin and prevents leaks around the stoma opening onto the peristomal skin.

Measurement of the stoma is necessary to determine the correct size of the stomal opening on the appliance. The opening should be large enough not only to cover the peristomal skin but also to avoid stomal trauma. The stoma will shrink within 6 to 8 weeks after surgery. Therefore, it needs to be measured at least once weekly during this time and as needed if the patient gains or loses weight.”3

The caregiver measures the size of a pre-cut ostomy system at the flange opening. Various sizes are available depending on the size of the stoma, brand and pouch system type. The ideal size for each stoma is slightly wider (about 3-4mm) than the edge of the stoma to allow comfort while maintaining a snug fit. A flange opening of the same size or smaller would cause trauma to the stoma during removal.

Convex flanges have a higher risk of causing injury if you wear an exact or compressing size. Pre-cut convex flanges are useful where flat pre-cut types are ineffective. Such situations include:

  • Flat or retracted stomas. A standard flat flange placed on such a stoma runs the risk of leaking.
  • Loop ostomy surgical procedures. These types of surgery often result in a retracted stoma. “A loop stoma is formed by pulling a loop of the colon to the surface and cutting an opening by creating a reverse fold in the intestine. Many times, this stoma may be reversed at a later date; therefore it is referred to as a temporary ostomy.”4

A loop ostomy can cause stoma prolapse. “Prolapse is especially common in the temporary loop stoma, and conservative management is recommended until the ostomy is reversed. If the prolapsed stoma is not at risk for obstruction or ischemia, it may be managed with manual reduction and a support binder or belt with a prolapse flap to stabilize the stoma. Unfortunately, a support belt may provide insufficient pressure to contain the prolapsed stoma. In this case, the size of the prolapse may be reduced by applying a cold compress or sprinkling table sugar on the exposed mucosa. The sugar creates an osmotic gradient that safely reduces the size of the prolapse.”5

  • Skin wrinkles and creases on the peristomal skin. This hinders flat flange adhesive from remaining in place. Some areas may not adhere, producing the accumulation of stoma discharge, causing leakage and irritation. “Leakage can quickly trigger chemical irritation within of hours of exposure. Leakage-associated dermatitis is best prevented by creating a properly protruding stoma (1–2 cm for colostomy, 2–3 cm for ileostomy) located on a flat area of the abdomen with a properly fit pouching system. After identifying and correcting the leakage (typically with filler pastes and/or application of a convex pouching system), affected skin tends to heal rapidly. Topical hydrocolloid powder will help prevent peristomal skin loss. Rarely, operative resting may be indicated for cases of recalcitrant leakage dermatitis that prove refractory to pouching system modifications.”6
  • Uneven surgical scars. The irregular skin surface might leave some areas without adhesion when using an ordinary flat flange. Convex flanges cover such areas, reducing chances of leakage. “The peristomal skin should be in the same condition as the skin on other portions of the abdomen. People with ostomies experience some degree of skin irritation from time to time. The most common causes are leakage of effluent onto the skin, allergic reactions to the adhesive material in a skin barrier or improper hygiene. A few simple preventive measures will help keep the skin free from irritation.”7
  • Peristomal pressure wounds. “Peristomal pressure wounds may develop from pouching apparatus, typically due to use of a convex appliance or stoma belt. Pressure wounds are commonly associated with parastomal hernias, particularly when a hard-convex ring is used to pouch. Full- or partial-thickness skin wounds may develop where the firm portions of the appliance contacts the apex of the hernia bulge. If a convex appliance is required to sustain an adequate seal, a soft or flexible convex pouching system may be used. […] Partial-thickness pressure wounds can be treated with skin barrier powder, and thin foam or hydrocolloid dressings. As with most peristomal skin conditions, close follow-up and meticulous care is required to prevent progression.

Epidermal stripping and mechanical skin trauma can occur from repeated applications of the appliance and from overzealous removal of old paste or tape residue. Mechanical trauma is best treated with reinforcing WOC nurse education sessions focusing on careful observation of pouching technique and wear-time counseling.”8

  • Stomas that change with posture, such as telescoping stomas. These are usually protruding when the patient is upright or sitting but retract during sleep, which can cause leaking.
  • A flabby abdomen. A flat pre-cut ostomy system is rarely effective in protecting the stoma and surrounding skin properly.

These factors are contraindicated for pre-cut flat ostomy flanges. When the stoma is regular with a spout-like shape, specialists recommend a standard pre-cut flange.  An absolute contraindication of a convex flange is a peristomal hernia. The convex flange can exert pressure on such a hernia which increases the risk of strangulation; therefore, they indicate a precut convex flange when the stoma has contour issues.

“Peristomal hernia is an incisional hernia that develops at the site of a colostomy or ileostomy, and is among the more common complications o intestinal stomas. The hernia usually lies within the attenuated layers of the abdominal wall, but in some instances, may tract subcutaneously adjacent to the stoma.

Like many stomal complications, formation of a hernia often results from one or more technical errors, which underscores the importance of proper perioperative planning and close attention to detail in the operating room. Other factors that may contribute to the development of peristomal hernias include obesity, advanced age, malignancy, malnutrition, steroid use, and increased abdominal pressure from ascites, chronic pulmonary disease, or obstructive uropathy. […]

However, a peristomal hernia may become more than a slight inconvenience for a patient already trying to cope with basic stoma care, especially if it becomes painful or precludes the adherence of a collecting pouch around the ostomy, resulting in leakage. Furthermore, a hernia sac with a narrow neck may even precipitate obstruction or strangulation of an intestinal loop, necessitating urgent laparotomy.”9

Even with a convex flange, the difficult peristomal surface elevates the risk of leaking and skin damage. To reduce this risk, you can use ostomy belts along with a convex flange. Hernia belts, assist the flange to maintain an even pressure on the baseplate adhesive, even where the contours create creases as in an overweight or flaccid abdomen. For improved results, use a belt from the same manufacturer of the flange.

Pre-cut ostomy systems are that they are faster to apply and more user friendly to patients with insufficient hand dexterity or painful conditions such as arthritis. Unlike cut-to-fit systems, user errors can cause leakage and skin irritation due to incorrect cutting and handling diminish.



(1) Colwell, J. C., Goldberg, M. T., & Carmel, J. E. (2012). Fecal & Urinary Diversions-E-Book: Management Principles. Elsevier Health Sciences. Available online at

(2) Hoeflok, J., Salvadalena, G., Pridham, S., Droste, W., McNichol, L., & Gray, M. (2017). Use of convexity in ostomy care: Results of an International Consensus Meeting. Journal of Wound, Ostomy, and Continence Nursing, 44(1), 55. Available online at

(3) Ignatavicius, D. D., & Workman, M. L. (2015). Medical-Surgical Nursing-E-Book: Patient-Centered Collaborative Care, Single Volume. Elsevier health sciences. Available online at

(4) Berg, D. T. (Ed.). (2001). Contemporary Issues in Colorectal Cancer: A Nursing Perspective. Jones & Bartlett Learning. Available online at

(5) Butler, D. L. (2009). Early postoperative complications following ostomy surgery: a review. Journal of Wound Ostomy & Continence Nursing, 36(5), 513-519. Available online at

(6, 8) Steinhagen, E., Colwell, J., & Cannon, L. M. (2017). Intestinal stomas—postoperative stoma care and peristomal skin complications. Clinics in colon and rectal surgery, 30(03), 184-192. Available online at

(7) White, L., Duncan, G., & Baumle, W. (2012). Medical surgical nursing: an integrated approach. Cengage Learning. Available online at

 (9) Fitzgibbons, R. J., Greenburg, A. G., & Nyhus, L. M. (Eds.). (2002). Nyhus and Condon’s hernia. Lippincott Williams & Wilkins. Available online at


María Laura Márquez
13 October, 2018

Written by

María Laura Márquez, general doctor graduated from The University of Oriente in 2018, Venezuela. My interests in the world of medicine and science, are focused on surgery and its breakthroughs. Nowadays I practice my more:

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