A New Bag Of Innovations
What products are facilitating quicker wound healing? What are some of the cutting-edge devices that are generating interest among podiatrists? What antibiotics are getting results? Are there new innovations that can provide adjunctive relief in diabetic foot wounds? In an attempt to answer some of these questions, we talked to leading podiatrists in the field. Without further delay, here’s what they had to say.
1. Promogran Matrix Wound Dressing. This chronic wound dressing was recently granted FDA approval for the treatment of exuding wounds, including diabetic, venous and pressure ulcers. David Armstrong, DPM, says Promogran’s combination of 45 percent oxidized regenerated cellulose (ORC) and 55 percent collagen may help facilitate improved healing in difficult wounds.
“(Promogran) appears to have a strong affinity to bind excess proteases in the wound,” points out Dr. Armstrong, the Director of Research and Education within the Department of Surgery, Podiatry Section at the Southern Arizona Veterans Affairs Medical Center. “When you combine this with its capacity to ionically bind and preserve endogenous and potentially exogenous growth factors, (Promogran) may help us move out of that chronically destructive inflammatory phase that is so deleterious to wound healing.”
Dr. Armstrong has had clinical experience with Promogran in the United Kingdom and has been evaluating results of the product over the last year. He is “encouraged” by the adjunctive potential of Promogran, saying that it may be particularly impactful when you combine it with other advanced wound healing modalities.
“I think (Promogran) could potentially be a powerful combination with other products such as currently available growth factors, hyaluronan, bioengineered tissue and even VAC therapy,” claims Dr. Armstrong.
2. Dermagraft. This human fibroblast-derived dermal substitute received FDA approval late last year for treating chronic, full-thickness diabetic foot ulcers of greater than six weeks duration. According to the manufacturer Smith and Nephew, you should not use Dermagraft over exposed tendon, capsule or bone.
Dr. Armstrong says Dermagraft has a number of key benefits, including:
• easy application;
• a superstructure of healthy, normal collagen; and
• facilitates a rapid decrease in wound depth.
When the modality received FDA approval, Dr. Armstrong predicted that Dermagraft would be a major advance in wound healing (see pg. 12, “News And Trends,” November 2001 issue).
“I believe strongly that if this modality is used as an adjunct to aggressive debridement, offloading, infection control and vascular intervention, where warranted, we will see not only widespread acceptance, but faster healing and ultimately, a reduction in the prevalence of lower extremity amputation,” noted Dr. Armstrong, who is also a Visiting Senior Lecturer of Medicine within the Department of Medicine at the Manchester Royal Infirmary at the University of Manchester in the United Kingdom.
Exploring The Effectiveness And Potential Of Ertapenem
3. Invanz (ertapenem). Recently FDA-approved for treating complicated skin and skin structure infections (CSSSI), this penem-class antibiotic has “good gram-positive activity, excellent gram-negative activity and great anerobic activity,” notes Warren Joseph, DPM, an Adjunct Associate Professor of Internal Medicine at the Temple University School of Medicine.
According to the manufacturer Merck, Invanz is indicated for CSSSIs caused by Staphylococcus aureus (methicillin-susceptible strains only), Streptocococcus pyogenes, Escherichia coli or Peptostreptococcus species.
Dr. Joseph says the one drawback to the drug is that it doesn’t cover Pseudomonas aeruginosa. However, Dr. Joseph adds that while you may isolate Pseudomonas from superficial wound swabs, it is usually not a major problem in most severe diabetic foot infections.
Indeed, Invanz may show particular promise in treating the diabetic foot. A pivotal trial submitted to the FDA was comprised of 500 CSSSIs (including nearly 100 severe diabetic foot infections). In this trial, researchers compared 1 gram, once-a-day dosing of Invanz to a 3.375g dosage every six hours of Zosyn (piperacillin/tazobactam). According to Dr. Joseph, the trial showed equal results between the two drugs.
“This once daily dosing will offer a great advantage over current multi-dose therapies in both cost savings and convenience for the patient,” explains Dr. Joseph, a Fellow of the Infectious Diseases Society of America. “It also makes outpatient parenteral therapy much more attractive.”
Adjunctive Relief For Severe Infections?
4. OsteoSet Resorbable Mini-Bead Kit. Dr. Armstrong believes that non-traditional vectors of drug delivery, like the OsteoSet Resorbable Mini-Bead Kit, are “very exciting” for the future.
According to the manufacturer Wright Medical Technology, you can use these calcium sulfate resorbable beads to treat bone voids caused by osteomyelitis in the feet of patients with diabetes.
“In essence, we use (the OsteoSet) as an adjunct to the customary parenteral/oral antibiotic regime in treating some of complex wounds in high-risk patients who have severe infections,” notes Dr. Armstrong. “Other podiatrists (most notably Allen Jacobs, DPM) have worked with this product for some time and have pioneered efforts in this area.”
There is a mixing process with the OsteoSet that is involved in melding the antibiotic with the resorbable beads, but Dr. Armstrong says it only takes a few minutes to do. He says he usually mixes the beads with a glycopeptide antibiotic like Vancomycin or an aminoglycoside like Tobramycin. Then you have pellets, which range in size between 3 to 6mm, that elute antibiotic as they resorb in the wound space. He says the pellets are radioopaque within 28 to 35 days.
Dr. Armstrong says the shelf life of the pellets created with the OsteoSet is another key benefit.
“In a recent study we performed, we found the antimicrobial shelf life of these physician-mixed pellets is at least six months in normal ambient temperature and humidity,” notes Dr. Armstrong.
He does caution that a significant drawback of using the product is you may frequently see a moderate amount of clear (sterile) drainage, particularly when you’re treating soft tissue infections. However, Dr. Armstrong says he has found some solutions for this problem.
“We have found that limiting the number of pellets we leave in soft tissue spaces seems to obviate the problem,” explains Dr. Armstrong. “We are constantly working with different dressing materials to try to mitigate this and have, to this point, been successful. This drainage has not been as much of a problem when we use the product to pack bone.”
Taking A Closer Look At A Time-Tested Implant
5. Biopro hemi-implant. When it comes to treating hallux rigidus, Harold Schoenhaus, DPM, prefers to perform a joint arthroplasty and replace the base of the proximal phalanx of the hallux. To achieve this goal, he uses two implants and one of them is the Biopro implant.
In his article, “Are First MPJ Implants Worth The Hype?” (see pg. 32, January issue), Dr. Schoenhaus praised the stem of the implant for “providing excellent stability and preventing rotation.” Dr. Schoenhaus, the Chief of Foot And Ankle Surgery at the Graduate Hospital in Philadelphia, also noted that the cobalt chrome implant is “basically inert and does not cause proliferative or inflammatory changes.”
John Vanore, DPM, who is on the Faculty of the Podiatry Institute, has also used the Biopro implant to treat hallux rigidus and degenerative arthrosis of the first MTP joint.
When it comes to advantages the Biopro implant gives you over other implants or procedures, Dr. Vanore cites the implant’s durability as a key benefit. He also notes that there are no problems with potential implant debris or host reactions to particulate debris, and that you can easily revise the hemi-implant procedure to a Keller or a first MTP joint fusion if necessary.
Drs. Schoenhaus and Vanore agree that the hemi-implant procedure does require limited bone resection. However, Dr. Schoenhaus notes that the minimal base resection does facilitate “good propulsive force and decreases the tendency for transfer metatarsalgia.”
In his aforementioned article, Dr. Schoenhaus noted that the hemi-implant procedure has stood the test of time in treating degenerative joint disease of the first MPJ.
“I’ve been able to achieve my goals of decreasing pain, increasing motion, restoring mechanics and providing a cosmetically acceptable result,” wrote Dr. Schoenhaus, who is board-certified by the American Board of Podiatric Surgery and the American Board of Podiatric Orthopaedics.
A New Answer In Healing Diabetic Ulcers?
6. Hyalofill. This wound dressing, a non-woven absorbent fleece dressing entirely comprised of Hyaff (an ester of hyaluronic acid), continues to earn raves from podiatrists.
In fact, a recent study of indolent diabetic foot ulcers found that using Hyalofill as part of a wound healing regimen resulted in an average healing time of 8.6 weeks. (See pg. 8, “News And Trends,” June issue.) When asked to comment on the study, which was co-authored by Dr. Armstrong, Alan J. Cantor, DPM, said these results are consistent with other studies published in Europe and his own experiences in using Hyalofill.
“We are finding a dramatic enhancement of granulation tissue where other previous therapies failed,” noted Dr. Cantor, who has authored a chapter on hyaluronic acid dressings in the Oxford University European Wound Healing Handbook. “We’re using (hyaluronan) on wounds of various etiologies and continually receiving positive responses.”
According to the manufacturer ConvaTec, Hyalofill has a number of indications, ranging from abrasions and superficial wounds to pressure ulcers and diabetic foot ulcers.
In his article, “What You Should Know About Wound Healing And Hyalofill” (see pg. 46, April issue), Dr. Cantor strongly emphasized the importance of appropriate wound bed preparation and offered other tips from his experience on how to maximize the effectiveness of Hyalofill.
In regard to dressing changes, he recommended doing them more frequently in heavily exuding wounds or wounds with a large amount of slough. Dr. Cantor noted that these environments would lead to more rapid hydrolysis and breakdown of hyaluronic acid. He also recommended moistening Hyalofill before applying it to extremely dry wounds.
Key Insights On The Potential Of Avelox
7. Avelox (moxifloxacin). This new quinolone antibiotic is approved for treating uncomplicated and complicated skin and skin structure infections caused by Staph and Strep, according to the manufacturer Bayer.
Dr. Joseph says Avelox is an exciting drug that is “very similar in spectrum and potential usage” to Trovan (trovafloxacin), a quinolone that was once heavily used by DPMs, but has since been severely restricted due to potential toxicities. In addition to working well against gram positives, gram negatives and anaerobes, Avelox also has the benefit of once-a-day oral dosing (400mg) without the side effects of Trovan, according to Dr. Joseph.
“It appears to be a significantly safer drug without the potential for all the toxicities seen with Trovan,” explains Dr. Joseph.
He cautions that the main drawback of using Avelox is the potential for QT interval lengthening, especially in patients who are on drugs that may cause the lengthening anyway.
Dr. Joseph also points out that Avelox is currently being studied in ongoing trials for potential use in moderate and severe diabetic foot infections.
Can The PSSD Enhance Diagnostic Skills?
8. Pressure Specified Sensory Device (PSSD). Using this device may help you arrive at more specific diagnoses for complex conditions, including multiple etiology heel pain.
Citing published studies by Weber and Dellon (the inventor of the device), Stephen Barrett, DPM, says the PSSD device gives you greater specificity and sensitivity than EMG testing and nerve conduction velocity (NCV) testing. Dr. Barrett, a Fellow of the American College of Foot and Ankle Surgeons, says this technology enables you to perform quantitative assessment of isolated peripheral nerves, which can be particularly beneficial in the tough heel pain cases.
“With better assessment available for evaluating isolated peripheral nerves like the medial calcaneal and the medial plantar nerve, you now have the ability to see the level (if any) of neurological pathology in the patient who has complex, recalcitrant heel pain,” points out Dr. Barrett in his article, “A Closer Look At Endoscopic Plantar Fasciotomy” (see pg. 38, May issue). “This is important because with clinical experience, many of the coexisting neural technologies you can now pick up with this technology were previously impossible to discern in some clinical situations.”
Dr. Barrett concedes that the device has a high learning curve. “The test is only as good as the technician,” he admits.
However, the time spent learning how to use the device may be time well spent when you consider the device’s diagnostic potential. Dr. Barrett says the PSSD device may also prove to be invaluable in determining the degree of peripheral neuropathy in patients with diabetes.
“Using the Pressure Specified Sensory Device is an excellent way to quantify and measure diabetic peripheral neuropathy,” says Dr. Barrett, the Research Director for the Houston Podiatric Foundation. “With the machine, we can assign a quantitative value on each particular patient’s neuropathy. We can then stage their disease process and we can tell when axonal degeneration starts to occur.”
Raising The Bar On Orthotic Flexibility And Durability
9. DBX6. It’s the materials that make the difference for the DBX6 orthotic and the people who wear the orthotic. According to the manufacturer Northwest Podiatric Laboratory, Inc., the DBX6 is a true composite device, comprised of fiberglass, graphite and resin, whereas many other orthotics are made out of thermoplastic material. While Northwest admits thermoplastics are better than they used to be, the company says orthotics made with that material are still susceptible to fatigue and cracking, slowly losing their shape and flattening out.
That’s not the case with the DBX6, according to Cleveland Smith, DPM, who has been using the DBX6 to help treat patients for the past year and a half. Dr. Smith says the DBX6 “gives you the best of flexibility and durability in the same compound.”
What’s particularly interesting about the orthotic is you can make one part more rigid while making another part more flexible. In terms of the flexibility, Dr. Smith says the orthotic has a “kind of spring-like rebound that imitates the spring ligament of the foot.” He says the DBX6 enables the foot to supinate easily and prevents the foot from staying pronated through the gait cycle. He has found the orthotic to be particularly helpful for athletic patients.
“They can really use the assistance in the resupination of the foot,” points out Dr. Smith. “(The DBX6) vastly improves foot function in that situation.”
The orthotic may not be well suited for all patients. For example, Dr. Smith says if he was treating a patient with a hypermobile foot and needed a really deep heel cup, he couldn’t use the DBX6.
Overall, however, given the lightweight device’s durability, flexible design and thin profile (1.5 mm thick), it should facilitate easy compliance for a fair number of patients.
Preventative Promise For Patients With Neuropathy?
10. FootScan. The FootScan is a portable device that uses infrared thermometry to monitor temperature increases in the foot caused by inflammation. While the device is not yet commercially available (perhaps a year or so away), a preliminary study of the device — presented at the American Diabetes Association (ADA) annual meeting in June — showed some early promise and potential.
According to a Reuters Health report, the study involved 85 diabetic patients, all of whom were given therapeutic shoes, insoles, basic education about foot care, and, if necessary, a scheduled DPM visit every ten weeks. Half of the patients were given the FootScan device and told to measure their foot temperature twice a day over a six-month period. Researchers instructed the patients that if they saw a four-degree increase in foot temperature, they should call a nurse and reduce pressure on the foot.
The preliminary study found that 16 percent of the non-FootScan group developed foot ulcers whereas only 2.4 percent of the group using the FootScan developed ulcers, according to the Reuters Health article.
Lawrence Lavery, DPM, who authored the study and presented it at the ADA meeting, says the device has preventative promise for patients with neuropathy.
“It gives patients who do not have any sensory feedback a mechanism to hear their feet talk to them again,” says Dr. Lavery, an Associate Professor in the Department of Orthopaedics Surgery and Rehabilitation at Loyola University Medical Center. “They have objective information to help them make decisions. Before they can see an area that is injured, they can detect a difference with the FootScan.”
When asked if the FootScan device would have an even greater effect if it was combined with activity monitoring via pedometers, Dr. Lavery says lack of access and comfortability in using computers may delay patient applicability in the short-term.
“In theory, activity monitoring is a great fit for the (FootScan),” notes Dr. Lavery. “The problem with the computerized systems is that many older Americans do not have computers or are uncomfortable using them even if their children buy them. In minority populations, computer access is worse. Obviously, this will change as Baby Boomers age and computer access is easier.”