and Reinhart T. Grundmann2
(1)
Department of Vascular Medicine, University Heart and Vascular Center at University Clinics Hamburg–Eppendorf, Hamburg, Germany
(2)
Former Medical Director, Community Hospital Altoetting-Burghausen, Burghausen, Germany
13.1 Guidelines
13.1.1 Society for Vascular Surgery (SVS)
The Society for Vascular Surgery in collaboration with the American Podiatric Medical Association and the Society for Vascular Medicine developed a clinical practice guideline for the management of diabetic foot (Hingorani et al. 2016). Specific areas of focus included (1) prevention of diabetic foot ulceration, (2) off-loading, (3) diagnosis of osteomyelitis, (4) wound care, and (5) peripheral arterial disease.
- 1.
Prevention of diabetic foot ulceration
Recommendation 1: We recommend that patients with diabetes undergo annual interval foot inspections by physicians or advanced practice providers with training in foot care (Grade 1C).
Recommendation 2: We recommend that foot examination include testing for peripheral neuropathy using the Semmes-Weinstein test (Grade 1B).
Recommendation 3: We recommend education of the patients and their families about preventive foot care (Grade 1C).
Recommendation 4:
- (a)
We suggest against the routine use of specialized therapeutic footwear in average-risk diabetic patients (Grade 2C).
- (b)
We recommend using custom therapeutic footwear in high-risk diabetic patients, including those with significant neuropathy, foot deformities, or previous amputation (Grade 1B).
- (a)
Recommendation 5: We suggest adequate glycemic control (hemoglobin A1c < 7% with strategies to minimize hypoglycemia) to reduce the incidence of diabetic foot ulcers (DFUs) and infections, with subsequent risk of amputation (Grade 2B).
Recommendation 6: We recommend against prophylactic arterial revascularization to prevent diabetic foot ulcer (DFU) (Grade 1C).
- 2.
Off-loading DFUs
Recommendation 1: In patients with plantar DFU, we recommend offloading with a total contact cast (TCC) or irremovable fixed ankle walking boot (Grade 1B).
Recommendation 2: In patients with DFU requiring frequent dressing changes, we suggest off-loading using a removable cast walker as an alternative to TCC and irremovable fixed ankle walking boot (Grade 2C). We suggest against using postoperative shoes or standard or customary footwear for off-loading plantar DFUs (Grade 2C).
Recommendation 3: In patients with nonplantar wounds, we recommend using any modality that relieves pressure at the site of the ulcer, such as a surgical sandal or heel relief shoe (Grade 1C).
Recommendation 4: In high-risk patients with healed DFU (including those with a prior history of DFU, partial foot amputation, or Charcot foot), we recommend wearing specific therapeutic footwear with pressure-relieving insoles to aid in prevention of new or recurrent foot ulcers (Grade 1C).
- 3.
Diagnosis of diabetic foot osteomyelitis (DFO)
Recommendation 1: In patients with a diabetic foot infection (DFI) with an open wound, we suggest doing a probe to bone (PTB) test to aid in diagnosis (Grade 2C).
Recommendation 2: In all patients presenting with a new DFI, we suggest that serial plain radiographs of the affected foot be obtained to identify bone abnormalities (deformity, destruction) as well as soft tissue gas and radiopaque foreign bodies (Grade 2C).
Recommendation 3: For those patients who require additional (ie, more sensitive or specific) imaging, particularly when soft tissue abscess is suspected or the diagnosis of osteomyelitis remains uncertain, we recommend using magnetic resonance imaging (MRI) as the study of choice. MRI is a valuable tool for diagnosis of osteomyelitis if the PTB test is inconclusive of if the plain film is not useful (Grade 1B).
Recommendation 4: In patients with suspected DFO for whom MRI is contraindicated or unavailable, we suggest a leukocyte or antigranulocyte scan, preferably combined with a bone scan as the best alternative (Grade 2B).
Recommendation 5: In patients at high risk for DFO, we recommend that the diagnosis is most definitively established by the combined findings on bone culture and histology (Grade 1C). When bone is débrided to treat osteomyelitis, we recommend sending a sample for culture and histology (Grade 1C).
Recommendation 6: For patients not undergoing bone débridement, we suggest that clinicians consider obtaining a diagnostic bone biopsy when faced with diagnostic uncertainty, inadequate culture information, or failure of response to empirical treatment (Grade 2C).
- 4.
Wound care for DFUs
Recommendation 1: We recommend frequent evaluation at 1- to 4-week intervals with measurements of diabetic foot wounds to monitor reduction of wound size and healing progress (Grade 1C).
Recommendation 1.1: We recommend evaluation for infection on initial presentation of all diabetic foot wounds, with initial sharp débridement of all infected diabetic ulcers, and urgent surgical intervention for foot infections involving abscess, gas, or necrotizing fasciitis (Grade 1B).
Recommendation 1.2: We suggest that treatment of DFIs should follow the most current guidelines published by the Infectious Diseases Society of America (IDSA) (Ungraded).
Recommendation 2: We recommend use of dressing products that maintain a moist wound bed, control exudate, and avoid maceration of surrounding intact skin for diabetic foot wounds (Grade 1B).
Recommendation 3: We recommend sharp débridement of all devitalized tissue and surrounding callus material from diabetic foot ulcerations at 1- to 4-week intervals (Grade 1B).
Recommendation 4: Considering lack of evidence for superiority of any given débridement technique, we suggest initial sharp débridement with subsequent choice of débridement method based on clinical context, availability of expertise and supplies, patient tolerance and preference, and cost-effectiveness (Grade 2C).
Recommendation 5: For DFUs that fail to demonstrate improvement (>50% wound area reduction) after a minimum of 4 weeks of standard wound therapy, we recommend adjunctive wound therapy options. These include negative pressure therapy, biologics (platelet-derived growth factor [PDGF], living cellular therapy, extracellular matrix products, amnionic membrane products), and hyperbaric oxygen therapy. Choice of adjuvant therapy is based on clinical findings, availability of therapy, and cost-effectiveness; there is no recommendation on ordering of therapy choice. Re-evaluation of vascular status, infection control, and off-loading is recommended to ensure optimization before initiation of adjunctive wound therapy (Grade 1B).
Recommendation 6: We suggest the use of negative pressure wound therapy for chronic diabetic foot wounds that do not demonstrate expected healing progression with standard or advanced wound dressings after 4–8 weeks of therapy (Grade 2B).
Recommendation 7: We suggest consideration of the use of PDGF (becaplermin) for the treatment of DFUs that are recalcitrant to standard therapy (Grade 2B).
Recommendation 8: We suggest consideration of living cellular therapy using a bilayered keratinocyte/fibroblast construct or a fibroblast-seeded matrix for treatment of DFUs when recalcitrant to standard therapy (Grade 2B).
Recommendation 9: We suggest consideration of the use of extracellular matrix products employing acellular human dermis or porcine small intestinal submucosal tissue as an adjunctive therapy for DFUs when recalcitrant to standard therapy (Grade 2C).
Recommendation 10: In patients with DFU who have adequate perfusion that fails to respond to 4–6 weeks of conservative management, we suggest hyperbaric oxygen therapy (Grade 2B).
- 5.
Peripheral arterial disease (PAD) and the DFU
Recommendation 1.1: We suggest that patients with diabetes have ankle-brachial index (ABI) measurements performed when they reach 50 years of age (Grade 2C).
Recommendation 1.2: We suggest that patients with diabetes who have a prior history of DFU, prior abnormal vascular examination, prior intervention for peripheral vascular disease, or known atherosclerotic cardiovascular disease (eg, coronary, cerebral, or renal) have an annual vascular examination of the lower extremities and feet including ABI and toe pressures (Grade 2C).
Recommendation 2: We recommend that patients with DFU have pedal perfusion assessed by ABI, ankle and pedal Doppler arterial waveforms, and either toe systolic pressure or transcutaneous oxygen pressure (TcPO2) annually (Grade 1B).
Recommendation 3: In patients with DFU who have PAD, we recommend revascularization by either surgical bypass or endovascular therapy (Grade 1B).
Recommendation 3 (technical and implementation remarks)
Prediction of patients most likely to require and to benefit from revascularization can be based on the Society for Vascular Surgery (SVS) Wound, Ischemia, and foot Infection (WIfI) lower extremity threatened limb classification.
A combination of clinical judgment and careful interpretation of objective assessments of perfusion along with consideration of the wound and infection extent is required to select patients appropriately for revascularization.
In functional patients with long-segment occlusive disease and a good autologous conduit, bypass is likely to be preferable.
In the setting of tissue loss and diabetes, prosthetic bypass is inferior to bypass with vein conduit.
The choice of intervention depends on the degree of ischemia, the extent of arterial disease, the extent of the wound, the presence or absence of infection, and the available expertise.
13.1.2 International Working Group on the Diabetic Foot (IWGDF)
Recommendations (Lipsky et al. 2016) are:
Classification/diagnosis
- 1.
Diabetic foot infection must be diagnosed clinically, based on the presence of local or systemic signs or symptoms of inflammation (strength of recommendation strong; quality of evidence low).
- 2.
Assess the severity of any diabetic foot infection using the Infectious Diseases Society of America/International Working Group on the Diabetic Foot classification scheme (strength of recommendation strong; quality of evidence moderate).
Osteomyelitis
- 3.
For an infected open wound, perform a probe-to-bone test; in a patient at low risk for osteomyelitis, a negative test largely rules out the diagnosis, while in a high-risk patient, a positive test is largely diagnostic (strength of recommendation strong; quality of evidence high).
- 4.
Markedly elevated serum inflammatory markers, especially erythrocyte sedimentation rate, are suggestive of osteomyelitis in suspected cases (strength of recommendation weak; quality of evidence moderate).
- 5.
A definite diagnosis of bone infection usually requires positive results on microbiological (and, optimally, histological) examinations of an aseptically obtained bone sample, but this is usually required only when the diagnosis is in doubt or determining the causative pathogen’s antibiotic susceptibility is crucial (strength of recommendation strong; quality of evidence moderate).
- 6.
A probable diagnosis of bone infection is reasonable if there are positive results on a combination of diagnostic tests, such as probe-to-bone, serum inflammatory markers, plain X-ray, magnetic resonance imaging (MRI) or radionuclide scanning (strength of recommendation strong; quality of evidence weak).
- 7.
Avoid using results of soft tissue or sinus tract specimens for selecting antibiotic therapy for osteomyelitis as they do not accurately reflect bone culture results (strength of recommendation strong; quality of evidence moderate).
- 8.
Obtain plain X-rays of the foot in all cases of non-superficial diabetic foot infection (strength of recommendation strong; quality of evidence low).
- 9.
Use MRI when an advanced imaging test is needed for diagnosing diabetic foot osteomyelitis (strength of recommendation strong; quality of evidence moderate).
- 10.
When MRI is not available or contraindicated, consider a white blood cell-labelled radionuclide scan, or possibly single-photon emission computed tomography (CT) and CT (SPECT/CT) or fluorine-18-fluorodeoxyglucose positron emission tomography/CT scans (strength of recommendation weak; quality of evidence moderate).
Assessing severity
- 11.
At initial evaluation of any infected foot, obtain vital signs and appropriate blood tests, debride the wound and probe and assess the depth and extent of the infection to establish its severity (strength of recommendation strong; quality of evidence moderate).
- 12.
At initial evaluation, assess arterial perfusion and decide whether and when further vascular assessment or revascularization is needed (strength of recommendation strong; quality of evidence low).
Microbiological considerations
- 13.
Obtain cultures, preferably of a tissue specimen rather than a swab, of infected wounds to determine the causative microorganisms and their antibiotic sensitivity (strength of recommendation strong; quality of evidence high).
- 14.
Do not obtain repeat cultures unless the patient is not clinically responding to treatment, or occasionally for infection control surveillance of resistant pathogens (strength of recommendation strong; quality of evidence low).
- 15.
Send collected specimens to the microbiology laboratory promptly, in sterile transport containers, accompanied by clinical information on the type of specimen and location of the wound (strength of recommendation strong; quality of evidence low).
Surgical treatment
- 16.
Consult a surgical specialist in selected cases of moderate, and all cases of severe, diabetic foot infection (strength of recommendation weak; quality of evidence low).
- 17.
Perform urgent surgical interventions in cases of deep abscesses, compartment syndrome and virtually all necrotizing soft tissue infections (strength of recommendation strong; quality of evidence low).
- 18.
Consider surgical intervention in cases of osteomyelitis accompanied by spreading soft tissue infection, destroyed soft tissue envelope, progressive bone destruction on X-ray or bone protruding through the ulcer (strength of recommendation strong; quality of evidence low).
Antimicrobial therapy
- 19.
While virtually all clinically infected diabetic foot wounds require antimicrobial therapy, do not treat clinically uninfected wounds with antimicrobial therapy (strength of recommendation strong; quality of evidence low)
- 20.
Select specific antibiotic agents for treatment based on the likely or proven causative pathogens, their antibiotic susceptibilities, the clinical severity of the infection, evidence of efficacy of the agent for diabetic foot infection and costs (strength of recommendation strong; quality of evidence moderate).
- 21.
A course of antibiotic therapy of 1–2 weeks is usually adequate for most mild and moderate infections (strength of recommendation strong; quality of evidence high).
- 22.
Administer parenteral therapy initially for most severe infections and some moderate infections, with a switch to oral therapy when the infection is responding (strength of recommendation strong; quality of evidence low).
- 23.
Do not select a specific type of dressing for a diabetic foot infection with the aim of preventing an infection or improving its outcome (strength of recommendation strong; quality of evidence high).
- 24.
For diabetic foot osteomyelitis, we recommend 6 weeks of antibiotic therapy for patients who do not undergo resection of infected bone and no more than a week of antibiotic treatment if all infected bone is resected (strength of recommendation strong; quality of evidence moderate).
- 25.
We suggest not using any adjunctive treatments for diabetic foot infection (strength of recommendation weak; quality of evidence low).
- 26.
When treating a diabetic foot infection, assess for use of traditional remedies and previous antibiotic use and consider local bacterial pathogens and their susceptibility profile (strength of recommendation strong; quality of evidence low).
13.2 WIfI-Classification-System
The Society for Vascular Surgery has created a new classification of the threatened lower extremity. Risk stratification is based on three major factors that impact amputation risk and clinical management: Wound, Ischemia, and foot Infection (WIfI) (Mills et al. 2014). The target population for this system includes any patient with
Ischemic rest pain, typically in the forefoot, with confirmatory, objective hemodynamic studies (Ankle-brachial index, ABI < 0.40; ankle pressure < 50 mm Hg; toe pressure < 30 mm Hg; Tissue-pO2 [TcPO2, transcutaneous oximetry] < 20 mm Hg)
A diabetic foot ulcer
Nonhealing lower limb or foot ulceration of at least 2 weeks duration
Gangrene involving any portion of foot or the lower limb.
Since each of the three categories (wound, ischemia, and foot infection) has four grades of severity, the system produces a grid with 64 theoretically possible clinical combinations (WIfI classes). The implementation of this classification system is intended to permit more meaningful analysis of outcomes for various forms of therapy in this heterogeneous population.
An early validation of the WIfI classification system has been published by Cull et al. (2014). Data were prospectively obtained in139 patients with foot wounds who presented for lower extremity revascularization. The WIfI clinical stage was predictive of 1-year limb amputation (stage 1, 3%; stage 2, 10%; stage 3, 23%; stage 4, 40%) and wound nonhealing (stage 1, 8%; stage 2, 10%; stage 3, 23%; stage 4, 40%). The data justify the validation of the WIfI classification system in further trials.
Causey et al. (2016) undertook a retrospective analysis of prospectively gathered registry data of consecutive patients with limb-threatening conditions admitted to a fully integrated vascular/podiatry service over a 16-month period. Upon admission, limb risk was stratified using the WIfI system and patient risk was categorized using PIII classification (PREVENT III (PIII) critical limb ischemia (CLI) risk score (Schanzer et al. 2009)). There were 174 threatened limbs (143 hospitalized patients). PIII risk correlated with mortality whereas WIfI stage strongly predicted initial hospital duration of stay, and key mid-term limb outcomes. Surgical revascularization performed best in the limbs at greatest risk (WIfI stage 4), and autogenous vein bypass was the preferred conduit for open bypass. These data supported the use of WIfI and PIII as complementary staging tools in the management of chronic limb-threatening ischemia.
Measurement of toe pressure is an important part of the WIfI classification system and is usually performed on the first toe. However, measurement in diabetics is sometimes impossible due to painful ulceration or tissue loss. In a prospective study, Bhamidipaty et al. (2015) found that second toe systolic pressure measurements were interchangeable with those of the first toe within acceptable limits of 5–10 mmHg. Therefore, it seems reasonable to use the second toe pressure, when first toe pressure cannot be obtained.
Zhan et al. (2015) analyzed a total of 201 consecutive patients with threatened limbs. Ninety-three percent of patients had diabetes mellitus. These patients were stratified into clinical stages 1–4 on the basis of the SVS WIfI classification. Among the 201 patients, 42 patients required major amputation. The classification system correlated with important clinical outcomes for limb salvage and wound healing. As the clinical stages progressed, the risk of major amputation increased, 1-year AFS declined, and wound healing time was prolonged. Overall, 90% of major amputations fell into the stage 4 group, and only 10% fell into the stage 3 group. One-year AFS rates were 100% (stage 1–2), 92% (stage 3), and 63% (stage 4), respectively.
13.3 Results
13.3.1 Revascularization
The guidelines of the Wound Healing Society (WHS) (Lavery et al. 2016) recommend that patients with ischemia should be considered for a revascularization procedure. Infrainguinal angioplasty and in situ bypass are associated with a significant improvement in ulcer healing (Level ll). Whether one of the two methods should be preferred to the other, is not stated. The International Working Group on the Diabetic Foot established a multidisciplinary working group to evaluate the effectiveness of revascularization of the ulcerated foot in patients with diabetes and PAD (Hinchliffe et al. 2016). There were no randomized controlled trials, but there were four nonrandomized studies with a control group. The major outcomes following endovascular or open bypass surgery were broadly similar among the studies. Following open surgery, the 1-year limb salvage rates were a median of 85%, and following endovascular revascularization, these rates were 78%. At 1-year follow-up, 60% or more of ulcers had healed following revascularization with either open bypass surgery or endovascular revascularization. There were insufficient data to recommend one method of revascularization over another.
Söderström et al. (2013) evaluated the benefit of infrapopliteal endovascular revascularization guided by an angiosome model of perfusion in the healing process of diabetic foot ulcers. A total of 250 consecutive legs with diabetic foot ulcers in 226 patients who had undergone infrapopliteal endovascular revascularization were evaluated. Direct flow to the foot ulcer based on the angiosome principle was achieved in 121 legs (48%) compared with 129 legs (52%) in which direct perfusion was not achieved. The ulcer healing rates were mean 48% at 6 months and 72% at 12 months for the direct group compared with 26 and 46% for the indirect group. The authors concluded that providing direct blood flow to the specific area of a diabetic foot ulcer has a favorable effect on ulcer healing and should be preferred to indirect revascularization. Fossaceca et al. (2013) also used the angiosome model to compare outcomes in patients treated by direct revascularization (DR) with patients treated with indirect revascularization (IR) technique. PTA was performed in 201 diabetic patients with below the knee disease. In 34 patients (16.9%), the treatment was performed via the IR technique. In this study, IR was similarly effective as compared to DR. Follow-up was 17.5 months. Major amputation rate was 9.6% in the DR group and 8.8% IR group, respectively. In both groups, there was a statistically significant increase of TcPO2 values at follow-up compared to baseline, without statistically significant differences in therapeutic efficacy.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
