Methods can vary, but compression is still best treatment

All techniques based on same principles

Compression therapy is recognized as the most effective treatment for venous ulcers. The simplest compression therapy options are elastic bandages or support stockings. Elastic bandages are typically wrapped around legs with ulcers that have been dressed, while stockings are usually used as a preventive measure against swelling or after an ulcer has healed.

These are also the cheapest options, but not necessarily the most effective for decreasing edema. Yet for some patients, particularly those covered by managed care plans or those on a fixed income, elastic wraps and stockings may be the only practical and affordable alternatives, says Tamara Fishman, DPM, a practicing podiatrist and president of the Wound Care Institute in North Miami Beach, FL. Medicare and private reimbursement policies for the various compression bandages vary from state to state and from plan to plan.

Fishman acknowledges that the basic elastic bandage may not be the best choice from a clinical standpoint. Maintaining adequate tension can be difficult as the bandage loosens or slips, and most patients and family caregivers are unable to rewrap them properly. But some type of compression is better than none at all. Clearly, the most desirable combination is a reliable bandaging system and a compliant patient who gets the bandage changed or rewrapped as prescribed.

Unna boot in use for 100+ years

Successful compression bandaging has a long history. Probably the best-known system is the Unna boot, which was invented in the late 1800s by the German dermatologist Paul Unna. It has been used with measurable success ever since. Medicare even has a separate code for the Unna boot, though the term is now used to describe various gauze bandages that have been modified from the original. Several companies sell Unna boots.

An Unna boot is a soft cast consisting of gauze that has been impregnated with various combinations of calamine, glycerin, zinc and other compounds. After being tightly wrapped around the leg, the impregnated gauze stiffens somewhat. Many clinicians who have used this simple compression wrap say it can be remarkably effective for decreasing edema and aiding wound closure, so it's not surprising that several imitators have become commercially available.

"The vast majority of venous stasis ulcers will heal with the use of a simple Unna boot," says John Macdonald, MD, medical director of the Wound Healing & Lymphedema Center in Ft. Lauderdale, FL. "We still haven't found anything that solves the problem like this basic system."

Then why not use them for every patient with venous ulcers? Several reasons, say experts. Esthetically, Unna boots are not particularly attractive, and they're messy. In between dressing changes (usually done weekly), the boot often becomes dirty and emits a foul odor, explains Morris Kerstein, MD, professor of surgery at Allegheny University of the Health Sciences in Philadelphia "Most people who work for a living can't use it," he says. The long interval between boot changes means microbial control of the wound must be achieved from the start because visualization is difficult.

Another drawback is that changing the Unna boot is a rather involved process that requires a health care professional and cannot be done at home by patients or family caregivers. In addition, the inelastic nature of the Unna boot may not, some clinicians argue, maintain constant pressure as swelling diminishes.

A product similar to the Unna boot is a simple wet-to-dry compression, which makes use of a gauze wrap that has been impregnated with either normal saline or, if the wound is infected, 3% boric acid solution. A compression liner is applied over the wet-to dry dressing, and a compression stocking designed to increase the venous pressure to 30 or 40 mm Hg at the ankle goes on last.

Charing Cross utilizes 4 layers

In 1988, clinicians at a London hospital developed a multilayered compression dressing that caught the attention of wound care professionals. It's called the Charing Cross high compression four-layer bandage system, named for the institution where it came into being. The inventors came up with the multilayered design because they believed it would address the primary reason why venous ulcers fail to heal: Simple elastic bandages apply adequate compression at first, but they cannot sustain tension as limb circumference diminishes.

The Charing Cross bandage system was designed to deliver 40 mm Hg pressure at the ankle, graduated to 17 mm Hg at the knee. It incorporates both absorbent dressings and elastic compression wraps. The first layer consists of orthopedic wool to absorb exudate, redistribute pressure around the ankle, and protect bony prominences. This layer is applied without tension in a loose spiral. Layer two is crepe, the function of which is to increase absorbency and to smooth the wool layer. It is also applied in a spiral. The developers of the Charing Cross system state that the crepe is "arguably the least effective layer in the combination."1

The third layer is Elset (Seton), described as a highly elastic, conformable compression bandage. This layer is applied at mid-stretch in a figure eight with a 50% overlap.

According to the Charing Cross developers, this layer results in a mean pressure of 17 mm Hg on average-size ankles. Finally, Coban (3M) is wrapped around the assembly to increase the pressure to its final level and keep the other layers firmly in place. The bandage is disposed of at every dressing change, usually every seven to 10 days.

When the Charing Cross bandage was used in a study involving 126 patients with chronic venous ulcers that had resisted treatment for a mean of 27 months, complete healing was achieved in three-quarters of the ulcers at 12 weeks follow-up. This compares to reports of 45% healing rates with simple elasticized bandages over wound dressings.2

Successful imitators

Two manufacturers, Johnson & Johnson and Smith & Nephew, took notice of the Charing Cross bandage and developed similar mutlilayer compression bandages of their own. Johnson & Johnson opted for a three-layer system called Dyna-Flex. The first layer is a proprietary padding and absorption wrap consisting of 100% cotton bonded to foam. The second layer is an elasticized cotton-based bandage, and the outside layer is a cohesive wrap designed to apply additional compression.

Smith & Nephew offers Profore, which is essentially the components of the Charing Cross bandage packaged in a kit. Members of the Charing Cross team aided in the product's development. Each kit costs about $18. Both Dyna-Flex and Profore are disposable products.

These bandages, like the Unna boot, generally remain in place for a week, and applying them properly requires a health care professional.

The length of time that any multilayered elastic bandage continues to apply the necessary pressure levels varies from patient to patient and according to the speed with which swelling decreases.

Once edema is completely eliminated and any venous ulcers have healed, elastic wraps should be replaced by measured compression garments, such as stockings, to keep down swelling. Below-the-knee stockings are the most practical, says Kerstein, because they should deliver from 30 to 40 mm Hg of pressure at the ankle. Compression stockings are also used as a preventive step for patients who do not yet have an open ulcer but have documented venous disease, and they have the advantage of being easily removed and replaced by the patient or a caregiver. They are usually washable (but shouldn't be put in a dryer) and some come with zippers. Patients should put on stockings before they get out of bed in the morning. A stocking's fit is based on limb circumference, so the garments cannot be purchased "off the shelf" by patients.

The products mentioned here are not the only elastic bandages that will yield adequate compression for venous ulcers and the medical conditions that lead to them. But for any type of compression bandage, clinicians must always keep one crucial point in mind, say Fishman and others: Before any compression therapy is applied, patients must be assessed for arterial circulation. Compression given to patients with arterial insufficiency can lead to disastrous results. (See story, p. 78.)

References

1. Moffatt CJ, Dickson D. The Charing Cross high compression four-layer bandage system. J Wound Care 1993; 2:91-94.

2. Blair SD, Wright DD, Backhouse CM, et al. Sustained compression and healing of chronic venous ulcers. Br Med J 1988; 297:1,159-1,161.