In
the past 30 years, limb salvage and wound care has changed so dramatically that
even the most advanced foot and leg ulcerations rarely lead to amputation.
The blood circulation so critical to saving limbs and healing ounds can be improved with a variety of techniques including balloon angioplasty, stents and bypasses, which allow skin grafts and a host of new wound care products to heal the newly perfused wound. Still, the earlier treatment begins, the better the
outcome. “It’s critical for doctors on the front line to either assess their patients’ circulation and wound healing capabilities or refer them to a specialized center like UCLA’s where we ‘bring the team to the patient’ to diagnose and treat circulatory issues,” notes Peter Lawrence, M.D., director of UCLA’s Gonda (Goldschmied) Vascular Center. Patients with vascular conditions
requiring assessment may have symptoms ranging from leg pain when walking or forefoot pain at rest to sores or ulcers that won’t heal. Gangrene is rarely the first sign of poor circulation.
Diagnostic
Tools
Avariety of diagnostic tools can help precisely pinpoint narrowing
or blockage in blood vessels that may be causing leg pain or hindering wound
healing:
- Physiologic tests,
such as sophisticated blood pressure devices designed for the legs, can assess
blood flow
- Specialized
ultrasound can determine the location of the blockage
- Magnetic resonance
imaging (MRI) can determine wound depth
- Magnetic resonance
angiography (MRA) creates a picture of the arteries and the site of the
blockage
- Contrast computed tomography (CTA) can
determine whether plaque exists in the wall of a blood vessel or aneurysm
“In many ways, our diagnostic abilities have improved 99 percent with all these tools, but there is no substitute for a careful physical examination. Vascular disease is one of the few remaining areas in medicine where, after a careful physical exam and blood flow studies, the patient can leave their first
office visit with an accurate determination of the problem and all of the potential treatments,” Dr. Lawrence notes, “However, we know that these imaging studies in many people without symptoms can reveal blockages that are not associated with the problem the patient is having and therefore do not need to
be treated. So the careful exam is critical to determining whether treatment of the blood vessels is necessary.” Developing a treatment plan for these patients requires input from a variety of specialists: vascular surgeons, podiatrists, interventional radiologists, plastic surgeons, and wound care and risk factor
specialists. Dr. Lawrence is convinced that this collaboration improves a patient’s chance of saving his or her limb.
Podiatry Techniques
Experts predict that 20 percent of all diabetic patients will develop a serious foot infection, some requiring lower extremity amputation, notes Robert K. Lee, D.P.M., UCLA podiatrist. A diabetic foot wound may form due to poor biomechanics, poor blood flow, poor sensation, or more commonly, from a combination of these factors.
When a diabetic patient develops neuropathy and gradually loses sensation in the foot, irritated areas can progress to wounds, ulceration and serious infection without the patient feeling any pain or discomfort, Dr. Lee explains. Often times, chronic diabetic foot wounds are healed by simple modification to shoes,
insoles, or with special shoes or casts, in conjunction with good local wound care. In some cases, surgical intervention is required to address biomechanical abnormalities and/or deformity in the foot. One method frequently used in
diabetics is lengthening the Achilles’ tendon. “Chronically elevated sugar levels can decrease collagen elasticity. As a result, the Achilles’ tendon contracts, causing the person to walk more on the balls of the feet,” says Dr. Lee. “By lengthening the Achilles’ tendon through a minimally invasive percutaneous technique, we can better distribute the weight-bearing forces
across the foot.” Fixed bony deformities such as bunions, hammertoes, or Charcot osteoarthropathy often induce the formation of pressure wounds and require surgical reconstruction. New techniques such as external fixation, bone
stimulators, and orthobiologics (e.g. autologous platelet concentrates) have helped to significantly advance foot reconstruction and limb salvage in diabetics. Even in the presence of osteomyelitis, more and more limbs are being
preserved with selective bone resections, partial foot amputations, vacuum assisted closure devices, and aggressive antibiotic therapy. Coupled with appropriate custom braces/anklefoot-orthoses, partial foot prostheses, and
diabetic shoes, many of these patients return to fairly normal levels of ambulation.
Endovascular
Therapy
Endovascular techniques work from inside the blood vessel to
improve circulation, explains Thomas McNamara, M.D., UCLA interventional
radiologist. In the past, a patient with an occluded artery in the lower abdomen
affecting wound healing in one leg would receive a surgical bypass. Today,
modified balloons and stents provide tools to open up vessels with minimal
trauma. Some tools being used and studied at UCLA include:
- Cutting balloons use blades the thickness of a hair to dilate vessels
- Atherectomy cuts and removes plaque from blood vessels
- Cryoballoons use liquid nitrogen to dilate vessels
- Drug-eluting stents impede renarrowing
- Cold laser excimers open blocked blood vessels
- Stent grafts incorporate a stent into a bypass graft
Dr. McNamara says, “Amputation is
not an answer; it’s an area of ignorance. We can improve blood flow in 85 to 90
percent of patients and, if necessary, repeat treatment to give an ulcer time to
heal.”
Vascular Surgery
We also have the expertise to bypass
veins to or near the foot to help heal wounds,” Dr. Lawrence says. “We can now
make a one-inch incision below the knee and harvest the vein from the groin to
the ankle. And that can be done in less than half an hour, significantly
improving postoperative recovery. We can also bypass to small arteries in the
foot, which are the size of a pencil lead, using a special microscope.” These
techniques are the same as are used for coronary artery bypass grafts.
One out of five patients who have
bypass or a balloon angiogram require a revision of his or her graft. Therefore,
surgeons tunnel grafts right below the skin so they are easily accessible, Dr.
Lawrence says. Unlike the heart, which is hard to monitor for renarrowing
because it is constantly beating, vascular disease elsewhere in the body can be
closely watched using ultrasound so that when grafts begin to narrow,
interventions can be effectively employed.
In addition to ultrasound
surveillance, patients need to control risk factors. “In most patients,
peripheral arterial occlusive disease is a manifestation of atherosclerosis. If
disease exists in the leg, chances are the carotid and coronary arteries are
also affected,” says Deborah Kass, the nurse practitioner who runs the risk
modification program for the UCLA Gonda (Goldschmied) Vascular Center. She works
with patients on their diet and exercise and, when indicated, starts
medications, such as statins, beta blockers and blood thinners, to help control
peripheral arterial occlusive disease. Wound Care Once circulation is improved,
wound care begins in earnest. “If you put patients in a wheelchair after a
bypass for three months to heal a wound, the odds of them walking are much lower
than if you can get the wound healed and get them in a special orthotic shoe so
they can walk right away. If we can cut down the length of time it takes to heal
by at least 50 percent, patients will be back to normal so much quicker and
their survival will be higher,” Dr. Lawrence explains. Patients with a wound
that fails to show improvement after three to four weeks of treatment, or that
is showing any signs of gangrene, should see a wound specialist. Debbie Caswell,
the nurse practitioner who runs the Wound Center at UCLA’s Gonda (Goldschmied)
Vascular Center, considers all causes that may be impeding wound healing— from
poor circulation and venous insufficiency to medications that a patient may be
taking. “The wound heals from the inside out. We work on nutrition (the body
needs protein to heal), and I put them on vitamin supplements, check nutritional
status and use short-term anabolic steroids when necessary to beef up the
ability to heal,” she says.
In addition, she discusses lifestyle
and family support with each patient. Patients with chronic wounds— especially
those who have had several courses of antibiotics—often harbor resistant
organisms that impede wound healing. Oral antibiotics and antimicrobial topical
solutions (including the currently popular silver) can help eliminate the
bioburden, Caswell observes. “When wounds heal, even at their strongest, the
scar is still only 80 percent as strong as normal tissue. Therefore, a lot of
the focus in our clinic is on taking care of the wound and preventing
recurrence,” Caswell notes. “Venous ulcers—most often around the ankles—are
particularly tenacious. From day one we educate these patients about how to
prevent recurrence and the surgeons do their part to repair faulty circulation
that is causing the wound.” A proliferation of new wound-care products exists,
and knowing the pros and cons of each product becomes more critical, both for
healing benefits and the expense of some of these treatments. Research currently
focuses on biophysical and cellular aspects of wound healing. “We’ve found that
chronic wounds are very different than acute wounds. The fluid in a chronic
wound contains very few growth factors but many inflammatory cytokines. There
are now dressings that control those inflammatory factors, which actually block
the effects on the growth factors. There are also biologic dressings that act as
skin substitutes,” Caswell says.
Hyperbaric oxygen provides another
option for wound healing for appropriate patients who can use a boost in oxygen
to aid in healing, to improve skin grafts, and to treat chronic osteomyelitis.
Surgical Wound Care
The first line of therapy for limb salvage is wound care and
then we add to that simpler surgeries such as skin grafts, VAC therapy and
flaps,” says James Watson, M.D., UCLA plastic surgeon. “Vacuum assisted closure
(VAC) therapy provides negative pressure wound care with a sponge, plastic
occlusive covering, and suction tubing that connects to a low-pressure suction
system.” VAC therapy is used to immobilize skin grafts, and is a procedure
patients can do themselves at home. In some cases, flap procedures transfer
tissue from another part of the body to the wound to cover exposed bone, close
blood vessels, and help heal large wounds. “Success rates for flaps at UCLA run
about 96 percent, compared to 70 percent around the country. Our success is due
to our team approach, patient selection, working with vascular surgeons, and
getting patients in optimal condition before attempting surgery,” says Dr.
Watson, who notes that he is starting to use arterial grafts from the forearm
and armpit for small bypass grafts in the foot.
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