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Study: PVD Patients With TMA At Elevated Risk For Post-Op Limb Loss

A study presented as a poster at the American College of Foot and Ankle Surgeons Annual Scientific Conference found a significantly elevated risk of limb loss following transmetatarsal amputation (TMA) in patients with peripheral vascular disease (PVD).

The study, which won first place in the scientific poster category, was a retrospective cohort study of 153 patients with peripheral vascular disease who had a transmetatarsal amputation. The study found an overall limb loss incidence of 44 percent after TMA regardless of what type of vascular intervention patients had. The authors noted 87 percent of patients who had an open bypass procedure healed the TMA stump and avoided limb loss in comparison to 51 percent of patients who had endovascular intervention.

The presence of PVD is a pivotal factor in post-TMA limb loss along with extensive soft tissue loss and infection of bone or soft tissue, according to Paul Kim, DPM, FACFAS.

In addition to PVD, Andrew Elliott, DPM, JD, cites reulceration as a common factor in limb loss after TMA. Saying reulceration is often the result of failing to appreciate underlying biomechanical deformities such as equinus or a residual forefoot varus, surgeons should address these deformities as part of the TMA, according to Dr. Elliott, who is affiliated with Gundersen Health System in LaCrosse, Wis.

However, Naohiro Shibuya, DPM, MS, FACFAS, considers PVD as only one of many risk factors associated with TMA failures, saying endovascular intervention or open bypass may not be enough to prevent post-TMA limb loss. He conducted a study comparing TMA with below-knee amputation (BKA), finding that transmetatarsal amputations are not as definitive or as durable as once thought with re-amputation and revision rates significantly higher for TMA in comparison to BKA.

“We feel that a good proportion of the TMAs are futile and not effective,” says Dr. Shibuya, a Professor of Surgery at the Texas A&M University College of Medicine and the Chief of the Podiatry Section, Surgical Services with the Central Texas VA Health Care System. “We focus so much on macrovascular disease but those patients at the end spectrum of the diabetes natural disease process have way more issues than just macrovascular disease.”

Dr. Shibuya says other factors, such as neuropathy, endothelial dysfunction, renal disease, mental health (often overlooked), and socioeconomic state are as significant if not more significant than macrovascular disease in post-TMA limb loss.  

“This is probably why we see a lot of complications after TMA despite revascularization,” he notes.

Dr. Kim sees value in both endovascular intervention and open bypass in TMA patients. He emphasizes that the effect of endovascular procedures is temporary and the procedure needs to work long enough for a wound to heal whereas an open bypass has greater longevity. In addition, both open bypass and endovascular procedures work best when there is increased perfusion of the target angisome so a plantar ulcer is more likely to respond to revascularization if the posterior tibial artery is the target, explains Dr. Kim, an Associate Professor at the Georgetown University School of Medicine.  

The timing of vascular intervention is important, notes Dr. Kim. He says an open bypass will almost immediately provide increased and maximal perfusion while an endovascular procedure may require several days until the small arterial to arterial connections begin to open up.

Dr. Elliott cites evidence suggesting that the ideal timing for TMA is about 48 to 72 hours after revascularization. He notes the goal is to do the revascularization prior to definitive closure “but a few days here or there doesn’t seem to matter.” If the revascularization does not occur prior to definitive closure, he says it should happen within 30 days of closure.

Is Radiofrequency Ablation Effective For Achilles Tendinosis? 

By Brian McCurdy, Managing Editor

Radiofrequency ablation with endoscopic assistance shows positive results for Achilles tendinosis in comparison with extracorporeal shockwave therapy (ESWT) and eccentric exercises, according to a recent study in the Journal of the American Podiatric Medical Association.

Seventy-eight patients with unilateral insertional Achilles tendinosis participated in the study. Eighteen patients had endoscopic debridement with radiofrequency ablation, 30 had ESWT and 30 patients performed eccentric exercises. Visual Analogue Scale (VAS) scores were better at 18 months in patients receiving radiofrequency in comparison to those who had ESWT and eccentric exercises, according to researchers.  

Lowell Weil, Jr., DPM, FACFAS, has been using radiofrequency ablation in the Achilles tendon for almost 10 years, citing success in previous studies. He says the therapy works for most patients with any tendinosis as documented on magnetic resonance imaging (MRI). The more pathology that is present, the less likely radiofrequency ablation will be successful but Dr. Weil says increased pathology will not prevent success.

In the earliest stage of Achilles tendinosis, Dr. Weil notes the combination of shoe gear and activity modifications, physical therapy including eccentric loading and Astym (Performance Dynamics), and a night splint provide success. When the aforementioned therapies are not effective, he says extracorporeal pulse activation treatment (EPAT)/ESWT can be excellent. Dr. Weil adds that sometimes using these treatments earlier for the condition provides quicker success. When Achilles pathology is worse, the combination of EPAT/ESWT with amniotic injection or platelet rich plasma (PRP) injection works well, according to Dr. Weil, the President of the Weil Foot and Ankle Institute. For worst cases of Achilles tendinosis, he will use the combination of radiofrequency, ESWT, amniotic injection or PRP.

Dr. Weil says for the Achilles, EPAT/ESWT “has continuously proved successful.” He will use EPAT for less substantial pathology and ESWT for more extensive pathology, noting that ESWT has been the subject of more studies and “proven in peer-reviewed literature (more) than all other treatments combined.”

Can A Portable OR Cart Make Surgery More Efficient? 

By Brian McCurdy, Managing Editor

An innovative surgical system may help surgeons improve instrument inventory management as well as efficiency in the OR.

Peter Blume, DPM, FACFAS, notes the GEO Cart (Gramercy Extremity Orthopedics) is a portable warehouse that facilitates remote, cloud-based tracking of products used in surgery along with continuous monitoring of all remaining inventory in the GEO Cart. Through the cloud, he notes the company receives this information and automatically ships sterile-packaged replenishment inventory to the OR.

The configuration of each GEO Cart system is customized to provide the full array of products that the facility and surgeon require, says Dr. Blume, an Assistant Clinical Professor of Surgery in the Department of Surgery and an Assistant Clinical Professor of Orthopaedics and Rehabilitation in the Department of Orthopaedics, Section of Podiatric Surgery at the Yale University School of Medicine in New Haven, Ct.

Dr. Blume says the GEO Cart eliminates delays in surgery due to receiving the wrong implants or instruments, bioburden issues, and lost time to due back table complexity. He says the system solves the problems of tracking and recording the use of implants, and confusion in determining what product one used in the OR.

Dr. Blume, who is an investor in Gramercy Extremity Orthopedics, says the packaging and label system are very simple and easy to understand while the GEO Cart’s instrument kits are sized to the correct implant to help eliminate confusion and delays during surgery. Additionally, the system provides electronic preference cards, which he says helps the OR staff pull the correct equipment and supplies.

The GEO Cart may also reduce OR costs. Dr. Blume says if his OR team has an issue with implants, instruments or trays, it will delay the case, sometimes while the patient is on the table, creating confusion, risk to the patient and higher costs. Having everything necessary in a sterile package, Dr. Blume says he and his team can react to changes in the surgery quicker.

“The GEO system provides single-use sterilized implants and instruments, thus eliminating the cost of sterilization of instrument and implant trays to the facility,” says Dr. Blume.

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With regard to the dismal outcome of TMA treatment, the authors surmise: “We feel that a good proportion of the TMAs are futile and not effective,” says Dr. Shibuya, a Professor of Surgery at the Texas A&M University College of Medicine and the Chief of the Podiatry Section, Surgical Services with the Central Texas VA Health Care System. “We focus so much on macrovascular disease but those patients at the end spectrum of the diabetes natural disease process have way more issues than just macrovascular disease.” Dr. Shibuya says other factors, such as neuropathy, endothelial dysfunction, renal disease, mental health (often overlooked), and socioeconomic state are as significant if not more significant than macrovascular disease in post-TMA limb loss. “This is probably why we see a lot of complications after TMA despite revascularization,” he notes. What about other factors? I recently wrote in my blog (see http://www.podiatrytoday.com/blogged/how-can-we-reduce-alarming-re-amputation-rate-patients-who-have-tma-procedures ) about the failure to address the significant mechanical effects on the patient who has undergone a TMA. Regardless of the vascular and metabolic issues which these authors propose, what about the significant pressure and shear forces which cause the inevitable ulceration in these patients which leads to further amputation? Here is the key section of my blog: "With few predictors of failure yet unpredictable outcome, there must be some skepticism when it comes to selecting TMA as a treatment option for patients with serious foot ulceration and infection. Perhaps it is time to re-evaluate the way we manage these patients postoperatively and realize that biomechanical factors may come into play, something we clearly overlook as a causative factor for failure of the TMA procedure. "There are several reasons for the high ulceration rate in patients who have undergone a TMA procedure. Studies have documented high plantar pressures in the residual foot in comparison to the contralateral foot in patients who have had TMA procedures.8,9 This may be related to the substantial gait disturbances that researchers have observed in this patient population.10 Mueller and coworkers studied patients with diabetes and TMA, and found less range of motion, lower peak moments and diminished power at the ankle in comparison to age-matched controls.11 "The standard of care for the patient with a TMA is protecting the residual foot with therapeutic footwear including a total contact foot orthosis with a toe filler.12,13 Given the high incidence of failure with this preventive intervention, is it not time for us to investigate other options to prevent re-amputation in patients who have undergone a TMA procedure?"
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