Podiatric Imaging - X-rays

With the exception of dermatology, most doctors are treating conditions that they cannot see with the naked eye.  In order to overcome this hurdle, many different types of imaging techniques and instruments have been developed in order to allow the doctor direct visualization of the problem area.  Let’s discuss the imaging most often used in podiatry.

The most commonly used imaging technique in podiatry is radiographs, or x-rays.  Although there are many exceptions to this rule, most people who walk into a podiatrist’s office will get x-rays.  X-rays are the best to order when a patient’s main complaint could potentially involve the bones or joints.  X-rays give only two dimensional images, so it is necessary to take x-rays from multiple angles so that the doctor can mentally put the images together to form a three dimensional picture.  X-rays give the doctor important clues in figuring out the pain a person is experiencing.  Fractures, foot mal-alignment, and arthritis can be diagnosed with simple x-rays.  If a person has stepped on a foreign object, x-rays can help to locate the position of it.  X-rays also can help to push the doctor to order additional tests or refer out to a different specialist if certain signs are present suggesting disease like rheumatoid arthritis, peripheral arterial disease, or other systemic disease.  It may even be necessary to get an x-ray with a severely infected ingrown toenail to see if the infection has gotten into the bone.

 

A concern that some patients have is the radiation associated with x-rays.  This was a problem in past decades with more primitive x-ray machines.  However, modern x-ray machines minimize the scatter of x-rays by directing the beams directly at the target object and having a very short exposure time.  Lead is worn to protect against the small amount of scatter.  X-rays are avoided if the patient is currently pregnant.  You can be assured the amount of radiation received by the foot is very small.  In fact, an x-ray exposes you to the same amount of radiation you would receive by spending about 5 minutes in the sun.  When compared to tanning, sun-bathing, or going without sunscreen in the sun, the radiation of an x-ray is insignificant.

Even though x-rays show bones and joints very nicely, they do not show much in terms of muscles, tendons, ligaments, or blood flow.  In some complicated fractures, it may be hard to determine the extent of the fracture with only an x-ray.  In these cases, ultrasound, Magnetic Resonance Imaging (MRI), computed tomography (CT or CAT Scan), or bone scans may be used.  We will discuss each of these imaging techniques in the upcoming weeks.

Wound Debridement Continued

Let’s finish our discussion on the different types of debridement.

Mechanical debridement is another method to remove non-viable tissue. This is accomplished by applying wet to dry dressings. Normal gauze is soaked in some type of antibacterial solution and packed into the wound. Solutions may be simple saline, Dakin’s (a diluted version of bleach), or other antibacterial solutions. This wet gauze once packed into the wound is covered by dry gauze then wrapped. This dressing is changed every day. As the packed gauze is removed, dead tissue is removed with it. This is a very inexpensive way to keep a wound clean, ward off infection and allows for evaluation every day during dressing change. This dressing may be used prior to application of a Negative Pressure Wound VAC. However, dressing changes may be a very painful as they rip superficial tissue off.

Autolysis is another option for debridement. Autolysis means to let the body digest or get rid of bad tissue by its own means. The body produces digestive enzymes called MMP’s. MMP’s at the wound’s surface liquefy the dead tissue. In order to allow the MMP’s to work, an occlusive dressing is placed over the wound. Occlusive dressings are not permeable to air and they keep the wound isolated from the outside environment. Occlusive dressings are relatively controversial. Some feel that occluding a wound keeps fluid and possibly unknown pus in a wound. However, studies show occluding a wound keeps its pH low, which inhibits bacterial growth and promotes oxygen unloading from red blood cells. Autolytic debridement is a more advanced way to debride a wound and requires frequent evaluation and inspection.

All in all, each method of debridement has its place in wound therapy. Different physicians prefer different dressings depending on their experience and training. If you are currently working to heal a wound, work with your doctor to know which type of debridement is best for your situation.

Debridement of Diabetic Wounds

In light of our recent discussions on maggot therapy, I thought it would be wise to discuss different ways to debride diabetic wounds and their associated pros and cons. Wound care is continually being assessed for effectiveness and continues to evolve. This is a short review of some of the many options available.

The most obvious way to debride a wound is manually with a curette or scalpel blade. This is the mainstay of wound debridement due to its practicality and ease. This type of debridement can be done quickly in an office visit or bedside without any major equipment. It is cheap and fast and allows for evaluation immediately after. In more recent times, debridement using a machine producing sound waves has been used bedside to remove dead tissue. However, there is no evidence showing that it is more effective than a scalpel blade.

Surgical methods are another way to debride wounds. This is usually reserved for unusually large or chronic wounds that need deeper or more radical debridement. Instruments like the VersaJet combine manual debridement with highly pressurized water to remove non-viable tissue. The benefit of surgical debridement is that the patient is sedated so the doctor can be more aggressive and insure all dead is tissue removed. However, taking the patient to the operating room, needing medical clearance and the assistance of an anesthesiologist makes surgical debridement less practical and is only used if medically necessary.

Another type of debridement is use of ointments that contain enzymes that breakdown dead tissue. This is especially useful in situations where a patient has full sensation to the wound. Manual debridement may prove to be too painful for the patient to go through. In contrast, enzymatic ointments slowly dissolve making it painless for the patient. The downside of enzyme ointments is that they take longer to work. In addition, enzymes are very sensitive to small changes in pH, making it possible for them to be inactivated if the wound is too acidic or basic.

We’ll discuss mechanical debridement, autolytic debridement, as well as how wound care dressings can effect debridement in our next post.

Medical Maggots continued

As more and more patients have difficult wounds to heal, we have looked to the past and brought back more primitive yet effective ways to clean and close wounds. One of these techniques is putting maggots into wounds.

Maggots are simply baby or immature flies. There are many species of flies, some of which are not beneficial for wounds. So it is not a good idea to go diving into dumpsters trying to find a nice batch of them. Special pharmacies have them available for wound care clinics and hospitals. Once ordered, they can be shipped overnight and ready the next day for application.

Once the maggots are placed in a wound, precautions need to be taken so that they do not escape. A mesh net is put over the wound, and the wound is surrounded by a very adherent material. This keeps them in the wound so that they can deliver maximum benefit. The maggots will then secrete enzymes that dissolve the dead and non-viable tissue at the wound’s surface over a couple days’ time. Once dissolved, the maggots consume the components of the dissolved material. After a couple days in the wound, the maggots can become much larger then when they were put in. They are removed from the wound to assess if they did their job well. It may take a couple of treatments of maggot therapy to remove all the dead tissue.

Another great benefit of maggot therapy is that it can be combined with other wound treatments without caution. Antibiotics, hyperbaric oxygen, and even wound VACs (vacuum assisted closure) can be used after maggots to increase the chance of healing.

Although putting eventual flies into a wound may not seem very cutting edge or fancy, some treatments stand the test of time. Maggot therapy can help wounds to heal and prevent amputations of the foot and leg. Ask your podiatrist if he feels that maggot therapy may be beneficial for the healing of your wound.

Medical Maggots

We have discussed extensively on this blog the devastating effects of diabetes on wound healing.  It can make sores that normally heal in days take months to heal.  The longer a wound stays unhealed and open, the greater chance of it getting infected and needing IV antibiotics at the hospital. 

Although the majority of wounds seen today are results of diseases like diabetes or venous insufficiency, that has not always been the case.  In past decades, the majority of wounds were related to war injuries.  In times of war, wounds were primarily results of bullets, explosions and shrapnel.  Back then, antibiotics has not been discovered and doctors were limited on how to clean wounds to prevent infection.  Most available treatments were harmful to both dead tissue and good tissue.  Many people lost limbs or even their lives from what would be considered today as minor wounds. 

Although there is documentation of maggots being used throughout history to help heal wounds, the first modern day use of them came during the American Civil War in the 1860s.  Doctors noticed that fly larvae seemed to leave good tissue alone and clean out only the bad.  Wounds treated with maggots seemed to heal faster and allow soldiers to keep their injured limbs.  Once antibiotics were discovered around the time of World War II, the combination of these two therapies proved to be a huge advancement in wound care.

In recent decades, maggot therapy has been used less and less as it seemed to be a very primitive form of treatment.  Obviously, the suggestion of using maggots to heal a wound has not been openly accepted by patients.   But when we remember that a diabetic’s immune system isn’t functioning properly, something has to be done to heal their wounds.  Maggots are now being used more and more to heal chronic wounds.  We’ll discuss how exactly maggots clean wounds in the next post.

Antibiotics Revisited

Several months ago we discussed on this blog the proper use of antibiotics for infections in the foot and leg. I wanted to revisit that subject somewhat by talking about three important points your doctor considers when deciding to give or not to give an antibiotic to you.

1. Antibiotics have not been shown to be beneficial for non-infected wounds.

The signs of infection are pain, swelling, redness, and warmth. If no signs or only one sign is present, the wound is probably not infected. In this scenario, neither oral or topical antibiotics have not been shown to help heal the wound. It has been thought that it would be good to preemptively treat the wound with antibiotics to ward off infection. However, this increases the chance of antibiotic resistant bacteria infecting the wound.

2. Mis-using antibiotics will decrease their effectiveness and increase their price

When antibiotics are used when no infection is present, the bacteria are given the opportunity to develop resistance to that antibiotic. Over time, as more and more bacteria develop resistance, a previously effective antibiotic may become useless. This will decrease the number of available effective antibiotics, thus driving up their price. New antibiotics take years to develop and will be slow to replace the ineffective ones.

3. When given antibiotics, make sure to take the entire dosage even if the infection is gone.

Even when the infection looks to be resolved, it is important to finish off the entire course of antibiotics your doctor has given you. They are dosed in a fashion to kill all harmful bacteria. If you stop taking them once things to be getter better, it gives the bacteria a chance to reproduce and develop resistance.

If your doctor decides against giving you antibiotics, trust in his/her judgment. However, if all the signs of infection or pus presents later, be sure to let your podiatrist know so that appropriate action can be taken.

3 things to heal a Diabetic Ulcer

Diabetic ulcers are becoming one of the major causes of amputation of a toe or limb.  A small sore can turn into a large wound in a very small amount of time.  If you are diabetic, it is important to seek proper care and precautions need to be taken in order to prevent ulcers and to stop an existing ulcers from progressing into uncontrollable wounds.  These precautions can be summarized into offloading, decreasing bacterial load, and insuring adequate blood flow.

Offloading simply means to not put weight on the ulcer.  Offloading is accomplished by wearing special shoes that allow you to walk, but decrease pressure on the ulcer site.  Excess walking will put pressure and friction on the wound site.  These forces prevent the skin cells from healing the wound.  If a diabetic with a history of diabetic wounds goes barefoot just once, an ulcer can open up in a short amount of time.

Moist, dead skin is a perfect environment for bacteria to multiply and potentially infect a wound.  By seeing your podiatrist regularly, this dead skin can be “debrided” or removed from around the ulcer.  This decreases the amount of bacteria threatening the wound so as to decrease the chance of the ulcer becoming infected.

Blood is the substance that contains all the growth factors and oxygen needed for the body to heal itself.  You may be confused to why you leave your podiatrist with your wound bleeding.  Debriding the wound not only removes dead skin, but it removes any dead material actually inside the wound to insure the base of the ulcer is receiving blood to its surface.

When these three precautions are met, ulcers tend to heal without complication.  With proper vigilance, a diabetic can avoid ulcerations and amputations altogether.