Pressure ulcers are a common affliction in two clinical situations: when people are immobilized, as in paralysis, coma, dementia, and forced bed rest; and when they must wear artificial devices, such as casts, splints, braces and prostheses. It is not surprising, therefore, that pressure ulcers frequently occur after spinal cord injury. In such cases they usually involve the ischial areas, or, less often, the Sacral and trochanteric regions.
The etiology of pressure ulceration is multifactorial. Blood pressure at the arterial end of the capillary loop is approximately 30 mm of mercury. Since pressures over bony prominences have been measured at between 40-150 mm of mercury, it seems clear that ischemic necrosis is the probable pathologic event. But there are other contributory causes as well: shearing injuries and other trauma; increased temperature, as with fever; moisture, including sweat and urine; poor nutrition; denervation and infection all increase the skin’s sensitivity to Ischemia.
The length of time necessary for ischemia to produce ulceration varies with each person and situation, but is not long in any case. Generally, it is believed that two hours of pressure-induced ischemia is sufficient to begin the process of skin ulceration.
Most pressure ulcers begin as a red area of skin. Given the magnitude of the problems that arise when such areas are allowed to progress to ulceration, this early stage should be considered a medical emergency. The pressure on the area should be relieved quickly and should not be re-applied until the skin has recovered, even if this requires hospitalization. A hospital stay of a few days, to heal this type of pressure problem, is preferable to the longer stay required after the skin and underlying tissues are actually destroyed.
Without proper care, the early stage proceeds to actual ulceration. If this ulceration involves only a small area of skin or a partial thickness skin loss, the sore may still be treated nonsurgically. Again, it is a medical emergency requiring relief of pressure, and if hospitalization is necessary to accomplish this, it should be done. If not treated successfully, the sore develops into a grade 3 or 4 pressure ulcer, involving breakdown of fat or bone tissue (see the pamphlet Taking Care of Pressure Sores for information on the stages of pressure ulcer development). These rarely heal without operative closure unless the area of skin loss and the zone of undermining are both very small.
The management of these deep ulcers cannot stop with skin flap closure by the plastic surgeon. It must also include additional training in skin care, transfers, etc. by the Physiatrist or primary care physician. Skin flaps are never as durable as the original skin cover. If the patient’s skin care habits permitted his original skin to break down, flaps have little to no chance without a change in behavior. Once the physiatrist or primary care physician is convinced that the patient is better able to care for his skin, ulcer closure, usually with flap tissue, is indicated. If the patient or his support system cannot be educated in skin care, then closure of the ulcer is not possible, and open wound care must be provided for the remainder of the patient’s life.
Care of deep ulcers at the University of Washington is provided on the Rehabilitation Service, as for other problems related to spinal cord injury. The first step is evaluation by the physiatrist. If it is decided that the patient and/or his family can learn and execute adequate skin care, further training is instituted and plans are made for surgical closure of the wound.
Preoperative care includes sharp debridement, hydrotherapy, and wet to dry dressing changes. Actual osteomyelitis is not common, so a workup for this diagnosis is rarely indicated. Spasms must be relieved with oral Dantrium, Valium or baclofen, or Intrathecal Baclofen, or with surgery. Bladder infections are controlled. Bowel control is achieved, although enemas are not used, since they may produce intraoperative evacuation. The postoperative immobilization plan is made and rehearsed.
Operative closure nearly always involves removal of the ulcer, trimming of the underlying bony prominence, and coverage with local flap tissue. Perioperative broad-spectrum antibiotics are administered. These operations commonly last 3 to 4 hours, and require one or two units of blood.
The postoperative plan involves three weeks of immobilization on some type of air bed. There should be no motion of the operative site. The surgical wounds are quite large, and involve large areas of undermining, and therefore will not tolerate motion too early. Two weeks may be adequate; one of the ongoing studies at the University of Washington is designed to test this possibility.
This treatment is lengthy and expensive, sometimes involving six or more weeks of inpatient care. Prevention should therefore be a primary goal in skin care. Turning the patient every two hours is fundamental, but proper hygiene and nutrition are also required. Proper pads for sitting are essential. Foam cushions and sheepskin are effective in the prevention of shearing and maceration, and are also inexpensive. Most importantly, quick and thorough treatment is vital in the early stages of redness, before actual ulceration occurs.