Definition & Overview

An ischial pressure ulcer is a wound that develops on the lower part of the buttocks due to prolonged pressure. The affected area is called the ischium, the curved portion of the pelvic bone, or the bone that is usually felt while sitting down.

The condition usually affects people who are bedridden or wheelchair-bound and do not have the ability to turn themselves over in bed. A pressure ulcer starts as a small wound on the skin, but can later affect the underlying tissue and even the bone.

In severe cases wherein the ulcer has reached the bone, surgeons recommend its surgical excision with ostectomy. Ostectomy is the surgical removal of a part of a bone. Also, because a good amount of tissue is lost in the process, the affected area is closed by transplanting tissue from other parts of the body in a procedure called flap or skin graft surgery.

Pressure ulcers develop in 4 stages. In stages 1 and 2, surgery is not usually required. In fact, the ulcer can be treated by debridement, which is the removal of dead tissue from a wound, such as a pressure ulcer or burn. However, stages 3 and 4 ischial pressure ulcers are more difficult to treat and will require surgery.

Who Should Undergo & Expected Results

The surgical excision of an ischial pressure ulcer is recommended for people with stages 3 or 4 of the condition. Those with early stages do not require surgery but are still closely monitored to prevent the condition from progressing.

Several factors contribute to the development of an ischial pressure ulcer. These include:

  • Shear - Shear is the result of stress created by the movement of different body tissues (bone, muscle, fat, and skin) on a moving or steady plane. To understand how shear works, imagine sitting down on a chair and moving your body sideways. The weight of the body on the buttocks deforms the tissue between the pelvic bone and skin as the body moves.
  • Friction - Friction occurs when the skin is rubbed against the surface of an object, such as a chair or bed.
  • Moisture - Moisture develops when the skin produces a small amount of liquids, such as sweat.
  • Pressure- Pressure occurs due to the weight of the body pressing down on an object.


A combination of the above components will lead to a skin injury, which usually starts small. However, as the break in the skin grows larger and becomes infected, a pressure ulcer develops. If the condition is not treated in the early stages, the pressure ulcer will continue to grow and affect the bone.

To treat the condition, the surgeon will remove dead tissue as well as a part of the affected bone. After removing the affected parts, the wound is closed. To do so, the surgeon will perform graft or flap surgery. Skin grafts can be performed when only a small amount of tissue has been affected by the pressure ulcer. If a larger amount of tissue and bone needs to be removed, the surgeon will perform myocutaneous flap surgery.

The procedure involves removing a sizeable amount of tissue and blood vessels from another portion of the body and transplanting it into the area where the pressure ulcer was removed.

Patients can expect a relatively good chance of recovery. However, treatment should continue until the wound has fully healed. After that, the patient’s nutrition should be closely monitored to ensure optimal health to prevent the condition from recurring.

How Does the Procedure Work?

The procedure begins by having the patient lie face down on an operating table. After the anaesthetic has taken effect, the surgeon will make an incision around the pressure ulcer. The pressure ulcer is then removed while ensuring that only a minimal amount of healthy tissue is removed in the process. The surgeon will then perform an ostectomy on the affected bone.

To close the gap, the surgeon will harvest tissue from other parts of the body, such as the thigh. The harvested tissue is then transplanted into the wound. In most cases, the harvested tissue will also include muscle.

The flap will then be stitched into the surrounding area, and the wound is left to heal. Recovery time will depend on the health condition of the patient, but it will usually take several months to fully recover.

Possible risks and complications

There are quite a number of risks and possibilities of complications associated with the excision of an ischial pressure ulcer with ostectomy. These include:

  • Skin graft or flap necrosis
  • Infections
  • Recurrence of pressure ulcer


The possibility of recurrence is high if the patient is left in a condition similar to when the initial pressure ulcer developed. To prevent this from happening, patients will need to learn how to relieve pressure, stress, and shear on the area. Most patients who undergo this procedure will require therapy after surgery to help them cope with their condition and to prevent recurrence.

References:

  • M. Marchi, S. Battaglia, S. Marchese, E. Intagliata, C. Spataro, R. Vecchio; “Surgical reconstructive procedures for treatment of ischial, sacral and trochanteric pressure ulcers”; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4511039/

  • Ricardo Goes Figueiras; “Surgical treatment of pressure ulcers: a two-year experience”; http://www.scielo.br/pdf/rbcp/v26n3/v26n3a10.pdf

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