Diabetic foot infections: stepwise medical and surgical management

Impact of diabetes and comorbidities on split-thickness skin grafts for foot wounds

BACKGROUND

Split-thickness skin grafts can be used for foot wound closure in diabetic and nondiabetic patients. It is unknown whether this procedure is reliable for all diabetic patients, with or without comorbidities of diabetes, including cardiovascular disease, neuropathy, retinopathy, and nephropathy.

METHODS

We retrospectively reviewed 203 patients who underwent this procedure to determine significant differences in healing time, postoperative infection, and need for revisional surgery and to create a predictive model to identify diabetic patients who are likely to have a successful outcome.

RESULTS

Overall, compared with nondiabetic patients, diabetic patients experienced a significantly higher risk of delayed healing time and postoperative complication/infection and, hence, are more likely to require revisional surgery after undergoing the initial split-thickness skin graft procedure. These differences seemed to be related more to the presence of comorbidities than to diabetic status itself. Diabetic patients with preexisting comorbidities experienced a significantly increased risk of delayed healing time and postoperative infection and a higher need for revisional surgery compared with nondiabetic patients or diabetic patients without comorbidities. However, there were no significant differences in outcome between diabetic patients without comorbidities and nondiabetic patients.

CONCLUSIONS

For individuals with diabetes but without exclusionary comorbidities, split-thickness skin grafting may be considered an effective surgical alternative to other prolonged treatment options currently used in this patient population.

Swab versus biopsy for the diagnosis of chronic infected wounds

OBJECTIVE

The goal of this review was to investigate the usefulness of a wound swab (using the Levine or Z technique) in comparison with a biopsy as a reliable method for the diagnosis of a chronic wound infection.

METHOD

A literature review using the electronic databases PubMed, CINAHL, and MEDLINE were searched by strategy. A total of 6 articles fulfilled the inclusion criteria.

MAIN RESULTS

The Levine technique detects more organisms in acute wounds, as well as in chronic wounds, than the Z technique. Comparing both with the biopsy as criterion standard, the diagnostic accuracy to diagnose a chronic wound infection by the Levine technique was higher in comparison to the Z technique. At a threshold of 3.7 × 10(4) microorganisms per swab, the Levine technique had a sensitivity of 0.90, a specificity of 57%, and a positive predictive value and negative predictive value of 0.77 and 0.91, respectively. Description of the method of swab taking was diverse and not uniform.

DISCUSSION

Only a few studies in the literature compare wound swabs with biopsies for the diagnosis of chronic infected wounds. Until now, the Levine technique has been considered as the most reliable and valid method, but there is an urgent need for a well-designed study with a sufficient number of patients to optimize the diagnostic accuracy of chronic infected wounds.

CONCLUSION

The best sampling technique for taking a swab has not yet been identified and validated. Until then, the authors recommend the Levine technique.

Using color to guide debridement

Chronic wounds are typically halted in the inflammatory stage of wound healing secondary to a prolonged inflammatory response of the body to bacterial colonization, as planktonic bacteria and biofilm and senescent cells present at the wound's edges. Surgical debridement of these wounds is a critical step taken by the treating physician to attain complete healing. In order for debridement to successfully reset the stages of wound healing, residual biofilm and senescent cells must be removed. Despite the importance of complete and thorough debridement, few methods exist, and even fewer articles have been written describing techniques to ensure that all portions of a wound are equally addressed with each procedure. Using methylene blue dye to color the wound allows the surgeon to address and debride all portions of the wound adequately. In addition, the surgeon must be very familiar with what the normal tissue colors are following removal of the methylene blue-dyed tissue. Getting to tissue with those colors provides an end point to the debridement and helps prevent removal of excess healthy tissue. This article describes the primary author's technique for staining tissues with methylene blue dye prior to wound debridement, as well as the colors to look for to signal completion of surgery. In addition, a review of biofilm and senescent cells is presented as both are targeted but frequently missed when wounds are incompletely debrided.

Quality assessment of tissue specimens for studies of diabetic foot ulcers

Diabetic foot ulcers (DFUs) represent an important clinical problem resulting in significant morbidity and mortality. Ongoing translational research studies strive to better understand molecular/cellular basis of DFU pathology that may lead to identification of novel treatment protocols. Tissue at the non-healing wound edge has been identified as one of major contributors to the DFU pathophysiology that provides important tool for translational and clinical investigations. To evaluate quality of tissue specimens and their potential use, we obtained 81 DFU specimens from 25 patients and performed histological analyses, immunohistochemistry and RNA quality assessments. We found that depth of the collected specimen is important determinant of research utility, and only specimens containing a full-thickness epidermis could be utilized for immunohistochemistry and RNA isolation. We showed that only two-thirds of collected specimens could be utilized in translational studies. This attrition rate is important for designs of future studies involving tissue specimen collection from DFU.

Vascular surgery, microsurgery and supramicrosurgery for treatment of chronic diabetic foot ulcers to prevent amputations

INTRODUCTION

Diabetic foot ulcers occur in approximately 2,5% of patients suffering from diabetes and may lead to major infections and amputation. Such ulcers are responsible for a prolonged period of hospitalization and co- morbidities caused by infected diabetic foot ulcers. Small, superficial ulcers can be treated by special conservative means. However, exposed bones or tendons require surgical intervention in order to prevent osteomyelitis. In many cases reconstructive surgery is necessary, sometimes in combination with revascularization of the foot. There are studies on non surgical treatment of the diabetic foot ulcer. Most of them include patients, classified Wagner 1-2 without infection. Patients presenting Wagner 3D and 4D however are at a higher risk of amputation. The evolution of microsurgery has extended the possibilities of limb salvage. Perforator based flaps can minimize the donorsite morbidity.

PATIENTS AND METHODS

41 patients were treated with free tissue transfer for diabetic foot syndrome and chronic defects. 44 microvascular flaps were needed. The average age of patients was 64.3 years. 18 patients needed revascularization. 3 patients needed 2 microvascular flaps. In 6 cases supramicrosurgical technique was used.

RESULTS

There were 2 flap losses leading to amputation. 4 other patients required amputation within 6 months postoperatively due to severe infection or bypass failure. Another 4 patients died within one year after reconstruction. The remaining patients were ambulated.

DISCUSSION

Large defects of the foot can be treated by free microvascular myocutaneous or fasciocutaneous tissue transfer. If however, small defects, exposing bones or tendons, are not eligible for local flaps, small free microvascular flaps can be applied. These flaps cause a very low donor site morbidity. Arterialized venous flaps are another option for defect closure. Amputation means reduction of quality of life and can lead to an increased mortality postoperatively.

Conservative management of diabetic foot osteomyelitis

In this retrospective study, 130 patients with diabetic foot osteomyelitis were analysed. 66.9% of these healed with antibiotic treatment alone and 13.9% needed amputation, of which 1.5% were major. Presence of MRSA was associated with adverse outcome (53.3% vs 21.1%, p=0.04) which was defined as death, amputation and failure to heal.

Concordance in diabetic foot ulcer infection

INTRODUCTION

Accurate identification of pathogens, rather than colonising bacteria, is a prerequisite for targeted antibiotic therapy to ensure optimal patient outcome in wounds, such as diabetic foot ulcers. Wound swabs are the easiest and most commonly used sampling technique but most published guidelines recommend instead removal of a tissue sample from the wound bed, which is a more complex process. The aim of this study was to assess the concordance between culture results from wound swabs and tissue samples in patients with suspected diabetic foot infection.

METHODS AND ANALYSIS

Patients with a diabetic foot ulcer that is thought to be infected are being recruited from 25 sites across England in a cross-sectional study. The coprimary endpoints for the study are agreement between the two sampling techniques for three microbiological parameters: reported presence of likely isolates identified by the UK Health Protection Agency; resistance of isolates to usual antibiotic agents; and, the number of isolates reported per specimen. Secondary endpoints include appropriateness of the empiric antibiotic therapy prescribed and adverse events. Enrolling 400 patients will provide 80% power to detect a difference of 3% in the reported presence of an organism, assuming organism prevalence of 10%, discordance of 5% and a two-sided test at the 5% level of significance. Assumed overall prevalence is based on relatively uncommon organisms such as Pseudomonas. We will define acceptable agreement as κ>0.6.

ETHICS AND DISSEMINATION

Concordance in diabetic foot ulcer infection (CODIFI) will produce robust data to evaluate the two most commonly used sampling techniques employed for patients with a diabetic foot infection. This will help determine whether or not it is important that clinicians take tissue samples rather than swabs in infected ulcers. This study has been approved by the Sheffield NRES Committee (Ref: 11/YH/0078) and all sites have obtained local approvals prior starting recruitment.

STUDY REGISTRATION

NRES Ref: 11/YH/0078, UKCRN ID: 10440, ISRCTN: 52608451.

2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections

Foot infections are a common and serious problem in persons with diabetes. Diabetic foot infections (DFIs) typically begin in a wound, most often a neuropathic ulceration. While all wounds are colonized with microorganisms, the presence of infection is defined by ≥2 classic findings of inflammation or purulence. Infections are then classified into mild (superficial and limited in size and depth), moderate (deeper or more extensive), or severe (accompanied by systemic signs or metabolic perturbations). This classification system, along with a vascular assessment, helps determine which patients should be hospitalized, which may require special imaging procedures or surgical interventions, and which will require amputation. Most DFIs are polymicrobial, with aerobic gram-positive cocci (GPC), and especially staphylococci, the most common causative organisms. Aerobic gram-negative bacilli are frequently copathogens in infections that are chronic or follow antibiotic treatment, and obligate anaerobes may be copathogens in ischemic or necrotic wounds. Wounds without evidence of soft tissue or bone infection do not require antibiotic therapy. For infected wounds, obtain a post-debridement specimen (preferably of tissue) for aerobic and anaerobic culture. Empiric antibiotic therapy can be narrowly targeted at GPC in many acutely infected patients, but those at risk for infection with antibiotic-resistant organisms or with chronic, previously treated, or severe infections usually require broader spectrum regimens. Imaging is helpful in most DFIs; plain radiographs may be sufficient, but magnetic resonance imaging is far more sensitive and specific. Osteomyelitis occurs in many diabetic patients with a foot wound and can be difficult to diagnose (optimally defined by bone culture and histology) and treat (often requiring surgical debridement or resection, and/or prolonged antibiotic therapy). Most DFIs require some surgical intervention, ranging from minor (debridement) to major (resection, amputation). Wounds must also be properly dressed and off-loaded of pressure, and patients need regular follow-up. An ischemic foot may require revascularization, and some nonresponding patients may benefit from selected adjunctive measures. Employing multidisciplinary foot teams improves outcomes. Clinicians and healthcare organizations should attempt to monitor, and thereby improve, their outcomes and processes in caring for DFIs.

Preoperative medical treatment in patients undergoing diabetic foot surgery with a Wagner Grade-3 or higher ulcer: a retrospective analysis of 52 patients

Diabetic foot ulcers (DFU) are one of the most important complications in people with diabetes mellitus. The present study was aimed to retrospectively review the efficacy of at least 1-week medical treatment before any surgical intervention in patients with Grade-3 and higher DFU according to Wagner's classification. A total of 52 patients (36 males and 16 females) hospitalized and treated between June 2006 and February 2009 and had initially received therapeutic treatment (local wound care, antibiotic therapy and blood glucose regulation) for a period of at least 1 week were included in the study. The level of amputation, rates of reulceration and mortality in both groups were recorded in the following period of 2 years. Group 1 (did not respond to preoperative medical intervention) included 16 patients where a surgical debridement, flap or skin graft surgery was performed in 2 (12.5%) patients, major amputation was performed in another 2 (12.5%) patients and minor amputation was performed in the remaining 12 (75%) patients. Of 36 patients in Group 2 (did respond to preoperative medical intervention), 5 (13.9%) patients underwent the surgical debridement, flap or skin graft surgery, 8 (22.2%) patients had a major amputation and the remaining 23 (63.9%) patients lead to a minor amputation. The ulcer recurrence and mortality rates were obtained as 2 (12.5%) and 2 (12.5%) in Group 1 and 2 (5.6%) and 1 (2.8%) in Group 2, respectively. Despite the lower rates of ulcer recurrence and mortality in patients having adequate responses to initial treatment before surgical procedures were performed, no statistically significant difference was observed between the 2 groups. In addition, there was no statistically significant difference between the levels of amputation in both groups.

Dermal substitute template use in diabetic foot ulcers: case reports

Diabetic foot ulcers are a source of significant morbidity. Maximizing limb salvage is an important long-term objective. The use of dermal substitutes to aid limb salvage and reduce amputation rates has been described recently in the literature. Dermal substitutes were initially described in burns and have been demonstrated to be useful adjuncts in the management of these wounds. In diabetic foot ulcer management, the outcomes of the use of the dermal substitutes are limited. The authors describe their experience of the use of INTEGRA®, a collagen-glycosaminoglycan dermal substitute, in 2 patients who presented with diabetic foot ulcers with exposed tendons.

Expert opinion on the management of infections in the diabetic foot

This update of the International Working Group on the Diabetic Foot incorporates some information from a related review of diabetic foot osteomyelitis (DFO) and a systematic review of the management of infection of the diabetic foot. The pathophysiology of these infections is now well understood, and there is a validated system for classifying the severity of infections based on their clinical findings. Diagnosing osteomyelitis remains difficult, but several recent publications have clarified the role of clinical, laboratory and imaging tests. Magnetic resonance imaging has emerged as the most accurate means of diagnosing bone infection, but bone biopsy for culture and histopathology remains the criterion standard. Determining the organisms responsible for a diabetic foot infection via culture of appropriately collected tissue specimens enables clinicians to make optimal antibiotic choices based on culture and sensitivity results. In addition to culture-directed antibiotic therapy, most infections require some surgical intervention, ranging from minor debridement to major resection, amputation or revascularization. Clinicians must also provide proper wound care to ensure healing of the wound. Various adjunctive therapies may benefit some patients, but the data supporting them are weak. If properly treated, most diabetic foot infections can be cured. Providers practising in developing countries, and their patients, face especially challenging situations.

Prognostic difference between soft tissue abscess and osteomyelitis of the foot in patients with diabetes: data from a consecutive series of 452 hospitalized patients

From January 2008 to December 2010, 452 patients with diabetes were admitted to our diabetic foot unit because of deep soft tissue abscess (group A: n = 210) or chronic osteomyelitis (group B: n = 242). Patients from group A underwent emergency debridement in the operating room. Patients from group B underwent elective surgery. Twenty-six (5.8%) major amputations were performed: of these, 18 (8.57%) were performed in patients from group A and 8 (3.31%) were performed in patients from group B (p = .024). Multivariate analysis showed the independent role on amputation outcome of the abscess (odds ratio, 2.64; p = .029; confidence interval [CI] 1.11 to 6.28), dialysis treatment (odds ratio, 3.17; p = .039, CI 1.06-9.51), and C-reactive protein > 0.5 mg/dL (odds ratio, 3.75; p = .022, CI 1.21-11.64). In group A, 43 (22.6%) patients healed only with drainage, and 147 (70.0%) minor amputations were performed: 53 (36.1%) at the level of the forefoot and 94 (63.9%) at the level of the midfoot. In group B, 234 (96.7%) minor amputations were performed, 208 (88.9%) at the forefoot and 26 (11.1%) at the midfoot level (p < .001). Fourteen postoperative complications occurred in patients from group A and 2 in patients from group B (p < .001). In group A, 3 patients died during hospitalization, 1 from septic shock and 2 from sudden death. None of the group B patients died. This study demonstrates that the severity of a foot soft tissue abscess is not comparable with that of a chronic osteomyelitis not only because of a higher rate of major amputation, but also because of a much more proximal level of minor amputation.

Diabetic lower extremity wounds: the rationale for growth factors-based infiltration treatment

Repair machinery and local infection control failure contribute to wound chronicity and lower extremity amputation in diabetic patients. In these wounds, inflammation is a proximal condition which disrupts wound matrix turnover and the local redox balance. Contemporary therapeutic interventions are relatively broad including drugs, devices and surgical procedures. However, clinical efficacy remains modest and recurrences are frequent. Recombinant growth factors advent was followed by their premature and empiric introduction in the clinical practice. Its topical administration is still challenged by local kinetic and pharmacodynamic limitations related to the hostile microenvironment of chronic wounds. The rationale of infiltrating epidermal growth factor (EGF) down inside complex diabetic wounds as an alternative treatment modality is described here. The concept emerged from two experimental evidences: (a) locally infiltrated EGF prevented trophic ulcers and limb necrosis upon denervation, (b) acute, controlled experimental wounds' exudate exhibited proteolytic activity. Depositing EGF in deep cells' responsive strata allows for two main pharmacological actions indispensable for chronic wounds healing: cyto-protection and proliferation of fibroblasts and endothelial cells, thus inducing progressive granulation. Ten years of clinical experience have validated laboratory and theoretical concepts, while most importantly have improved quality-of-life to thousands of diabetic patients.

An overview of foot infections in diabetes

Patients with diabetes are prone to ulcerations of the lower extremities, frequently complicated by infection, and are then reliant upon their caregivers for preservation of their limbs without the dreaded outcome of amputation. The enormous tolls of foot infections in diabetes, in terms of both health-related quality of life issues and associated economic burdens, have only been fully realized within the last few decades, and it is anticipated that these burdens will only increase over time. Early and appropriate antibiotic treatment targeting the most likely etiologic pathogens is a cornerstone of management of foot infections in diabetes, but these decisions are now complicated by the emergence of resistant organisms, particularly methicillin-resistant Staphylococcus aureus and multidrug-resistant Gram-negative species. This review will examine the impact of foot infections in diabetes and the overall care and management of the diabetes patient with foot infection, including the potential value of emerging antibiotic therapies within the milieu of antibiotic resistance.

[The infected diabetic foot]

Infections in the diabetic foot are regularly the consequence of neuropathic, ischemic, or combined neuropathic-ischemic ulcerations which cause substantial morbidity including a high rate of major amputations. Diabetic foot infections are responsible for substantially high costs of diabetic treatment and induce an increased rate of mortality. An early diagnosis on the basis of clinical presentation, laboratory results, and radiologic imaging together with an adequate classification of the severity of infection represents the key for a successful intervention strategy. Severe infections in diabetic feet have a poorer prognosis than mild or moderate infections. A guideline which includes a multifaceted approach to infection control by débridement, antibiotic therapy, and revascularization before definitive reconstruction of the defect may aid in reducing the risk of amputation and improving the quality of life and mobility of the patient. This can be realized by multidisciplinary cooperation. Additional preventive measures such as osseous and soft tissue reconstructions during the infection-free period to establish a plantigrade and ulcer-free foot together with education and routine follow-up controls provide the basis for a long-term reduction of ulcer and infection recurrence with progressive deterioration of the prognosis.

The use of superoxidized aqueous solution versus saline as a replacement solution in the versajet lavage system in chronic diabetic foot ulcers: a pilot study

BACKGROUND

The removal of necrotic tissue from chronic wounds is required for wound healing to occur. Hydrodebridement (jet lavage) and superoxidized aqueous solution have been independently used for debriding wounds. We sought to investigate the use of superoxidized aqueous solution with a jet lavage system.

METHODS

Twenty patients with diabetic foot ulcers were randomly assigned in a 1:1 ratio to receive jet lavage debridement with either superoxidized aqueous solution or standard saline weekly.

RESULTS

There was no significant difference between the two treatments in the reduction of bacterial load or wound size in 4 weeks. No adverse reactions were reported for either treatment.

CONCLUSIONS

The use of superoxidized aqueous solution for jet lavage debridement seemed to be as safe and effective as saline. Future investigations should concentrate on whether superoxidized aqueous solution may reduce the bacterial air contamination associated with hydrodebridement.

Seminar Review: A Review of the Basis of Surgical Treatment of Diabetic Foot Infections

Infection is an extremely challenging complication of foot ulcers in patients with diabetes. Surgery as part of a multidisciplinary approach is key in the management of many types of diabetic foot infections (DFIs). Unfortunately, the surgical treatment of DFIs is based more on clinical judgment and less on structured evidence, which leaves unresolved doubts. The clinical presentation of DFIs is varied. This review examines the basis of nonvascular surgical treatment of DFIs, emphasizing the importance of the anatomic concepts of the foot, the variety of its clinical presentations, and the concepts of timing surgery. Recent evidence and case reports based on the author’s experience are presented in 2 parts. The first part examines clinical presentation of infections, whereas the second part deals with imaging, foot anatomy, and some case reports.

A reliable surgical approach for the two-staged amputation in unsalvageable limb and life threatening acute progressive diabetic foot infections: tibiotalar disarticulation with vertical crural incisions and secondary transtibial amputation

BACKGROUND

If all efforts to treat acute progressive diabetic foot infection remain insufficient, the decision of major amputation should be undertaken. For this purpose, guillotine amputation is usually performed first. However, guillotine amputation below the knee level may cause the corresponding infection to spread to preserved anatomical spaces.

METHOD

First stage of our procedure consists of tibiotalar disarticulation and vertical incisions performed throughout the lower leg to remove the septic foot and drain the compartments. During the interval period, appropriate antibiotherapy and wound care are applied. After the interval period, definitive transtibial amputation is performed in the second stage.

RESULTS

Fifty-nine percent of the 62 transtibial amputations were healed completely. Failure developed in 3 cases which required opening of the amputation stump. In one patient, revision amputation at a higher transtibial level was done. Infection and necrosis reached to the knee joint in the other two patients and transfemoral amputation became the only treatment option for these 2 cases.

CONCLUSION

Tibiotalar disarticulation with vertical lower leg incisions as a first stage of two-stage transtibial amputation is a safe and reliable method. It reduces the risk of unnecessary tissue sacrifice and failure rate of the secondary transtibial amputation.

A step-wise approach for surgical management of diabetic foot infections

Diabetic foot disease frequently leads to substantial long-term complications, imposing a huge socioeconomic burden on available resources and health care systems. Peripheral neuropathy, repetitive trauma, and peripheral vascular disease are common underlying pathways that lead to skin breakdown, often setting the stage for limb-threatening infection. Individuals with diabetes presenting with foot infection warrant optimal surgical management to effect limb salvage and prevent amputation; aggressive short-term and meticulous long-term care plans are required. In addition, the initial surgical intervention or series of interventions must be coupled with appropriate systemic metabolic management as part of an integrated, multidisciplinary team. Such teams typically include multiple medical, surgical, and nursing specialties across a variety of public and private health care systems. This article presents a stepwise approach to the diagnosis and treatment of diabetic foot infections with special emphasis on the appropriate use of surgical interventions and includes the following key elements: incision, wound investigation, debridement, wound irrigation and lavage, and definitive wound closure.

The use of a dermal substitute to preserve maximal foot length in diabetic foot wounds with tendon and bone exposure following urgent surgical debridement for acute infection

In this study, we evaluated the utility of a dermal substitute for preserving maximal foot length after urgent surgical debridement. Patients referred to our Diabetic Foot Center with foot lesions were assessed for sensory-motor neuropathy, infection and critical limb ischaemia. The presence of acute foot infection indicated the need for immediate surgical debridement. The degree of amputation, if necessary, was based on the amount of apparently non infected vital tissue. When vital tendon/bone tissue remained exposed, the lesion was covered with a dermal substitute. From January to December 2008, 393 patients underwent surgical treatment for diabetic foot syndrome; 30 patients underwent immediate surgical debridement resulting in exposed tendon and/or bone tissues. An average of 4.4 +/- 2.1 days following surgical debridement, all 30 patients underwent dermal regeneration template grafting to cover-exposed healthy tendon and bone tissues, instead of achieving primary wound closure with a proximal amputation. After 21 days, a skin graft was performed. Complete wound healing occurred in 26 patients (86.7%). In these patients, the amputation level was significantly more distal (P < 0.003) with respect to that potentially required for immediate wound closure. The average healing time was 74.1 +/- 28.9 days. Four patients underwent a more proximal amputation. No patients underwent major amputation. The use of the dermal substitute for treating exposed tendon and bone tissues allowed timely wound healing and preserved maximal foot length. Continued follow-up will allow assessment of long-term relapse and complication rates. Such treatment could constitute part of the comprehensive management of diabetic wounds.

Preoperative Doppler assessment for transmetatarsal amputation

A thorough preoperative vascular evaluation should be performed before the initiation of any lower extremity surgical intervention, but particularly in situations of diabetic foot reconstruction with compromised blood flow. The intended emphasis of this brief report is to provide the foot and ankle surgeon with an appreciation for the clinical vascular anatomy of the transmetatarsal amputation through a handheld Doppler examination.

Diabetic foot infections: a team-oriented review of medical and surgical management

As the domestic and international incidence of diabetes and metabolic syndrome continues to rise, health care providers need to continue improving management of the long-term complications of the disease. Emergency department visits and hospital admissions for diabetic foot infections are increasingly commonplace, and a like-minded multidisciplinary team approach is needed to optimize patient care. Early recognition of severe infections, medical stabilization, appropriate antibiotic selection, early surgical intervention, and strategic plans for delayed reconstruction are crucial components of managing diabetic foot infections. The authors review initial medical and surgical management and staged surgical reconstruction of diabetic foot infections in the inpatient setting.

Serial surgical debridement: a retrospective study on clinical outcomes in chronic lower extremity wounds

This investigation was conducted to determine if a correlation exists between wound healing outcomes and serial debridement in chronic venous leg ulcers (VLUs) and diabetic foot ulcers (DFUs). We retrospectively analyzed the results from two controlled, prospective, randomized pivotal trials of topical wound treatments on 366 VLUs and 310 DFUs over 12 weeks. Weekly wound surface area changes following debridement and 12-week wound closure rates between centers and patients were evaluated. VLUs had a significantly higher median wound surface area reduction following clinical visits with surgical debridement as compared with clinical visits with no surgical debridement (34%, p=0.019). Centers where patients were debrided more frequently were associated with higher rates of wound closure in both clinical studies (p=0.007 VLU, p=0.015 DFU). Debridement frequency per patient was not statistically correlated to higher rates of wound closure; however, there was some minor evidence of a positive benefit of serial debridement in DFUs (odds ratio-2.35, p=0.069). Our results suggest that frequent debridement of DFUs and VLUs may increase wound healing rates and rates of closure, though there is not enough evidence to definitively conclude a significant effect. Future clinical research in wound care should focus on the relationship between serial surgical wound debridement and improved wound healing outcomes as demonstrated in this study.

The treatment of diabetic foot infections: focus on ertapenem

Clinically, 3 distinct stages of diabetic foot infection may be recognized: localized infection, spreading infection and severe infection. Each of these presentations may be complicated by osteomyelitis. Infection can be caused by Gram-positive aerobic, and Gram-negative aerobic and anaerobic bacteria, singly or in combination. The underlying principles are to diagnose infection, culture the bacteria responsible and treat aggressively with antibiotic therapy. Localized infections with limited cellulitis can generally be treated with oral antibiotics on an outpatient basis. Spreading infection should be treated with systemic antibiotics. Severe deep infections need urgent admission to hospital for wide-spectrum intravenous antibiotics. Clinical and microbiological response rates have been similar in trials of various antibiotics and no single agent or combination has emerged as most effective. Recently, clinical and microbiological outcomes for patients treated with ertapenem were equivalent to those for patients treated with piperacillin/tazobactam. It is also important to judge the need for debridement and surgery, to assess the arterial supply to the foot and consider revascularization either by angioplasty or bypass if the foot is ischemic. It is also important to achieve metabolic control. Thus infection in the diabetic foot needs full multidisciplinary treatment.

Swab cultures for diagnosing wound infections: a literature review and clinical guideline

Infection is a major causative factor in delayed and nonhealing wounds. Indiscriminate and routine wound cultures are not recommended, but a culture is indicated to identify the causative organisms and to guide antibiotic therapy when clinical suspicion of an infection exists. Although tissue biopsy is considered the gold standard to diagnose infection, it is rarely used in clinical settings. Swab culture is the most frequently employed method of confirming wound infection in the United States, but a standardized procedure is lacking. Properly performed swab cultures provide useful data to augment diagnostic and therapeutic decision making. The specific aim of the review is to propose a research-based guideline to perform swab cultures as a basis to improve clinical practice and encourage research to establish the reliability and validity of the swab technique.

Wound infection-associated pain

Not only does wound infection and the release of pro-inflammatory modulators result in pain and delayed healing, but pain-related stress reduces the immune response to infection. Treatment of pain and infection should be equal priorites.

Use of a Nanoflex powder dressing for wound management following debridement for necrotising fasciitis in the diabetic foot

This paper discusses the application of Nanoflex powder dressing for management of complex soft tissue wounds. A case report is presented detailing the management of a 43-year-old Native American woman with diabetes mellitus who required serial debridements for necrotising fasciitis. Following debridement, the patient was left with a large dorsal foot wound and was transitioned through multiple advanced wound healing modalities. Negative pressure wound therapy (NPWT) was initially utilised in the early postoperative setting to control drainage and to promote granulation tissue; the patient was subsequently transitioned to a Nanoflex powder dressing on postoperative day 4. She reported a decrease in pain associated with dressing changes when transitioned from NPWT to the use of Nanoflex powder dressing. We hypothesise that this pain reduction is the result of a light cooling effect of the exudate-controlling dressing and subsequent reduction in inflammation as well as the total contact nature of the dressing. Nanoflex powder dressings are a recently developed advanced wound healing modality with promise in the management of complex soft tissue wounds, both as a primary wound dressing as well as a delivery platform for analgesics, antimicrobials and pro-angiogenic compounds.

"Opening" the mesenchymal stem cell tool box

Adult mesenchymal stem cells (MSCs) are adherent stromal cells able to self-renew and differentiate into a wide variety of cells and tissues. MSCs can be obtained from distinct tissue sources and have turned out to be successfully manipulated in vitro. As adult stem cells, MSCs are less tumorigenic than their embryonic correlatives and posses another unique characteristic which is their almost null immunogenicity. Moreover, these cells seem to be immunosuppressive in vitro. These facts together with others became MSCs a promising subject of study for future approaches in bioengineering and cell-based therapy. On the other hand, new strategies to achieve long-term integration as well as efficient differentiation of these cells at the area of the lesion are still challenging, and the signalling pathways ruling these processes are not completely well characterized. In this review, we are going summarize the general landscape and current status of the MSC tool as well as their wide potential in tissue engineering, from neuronal to tooth replacement. Highlights and pitfalls for further clinical applications will be discussed.

Hydrodebridement of wounds: effectiveness in reducing wound bacterial contamination and potential for air bacterial contamination

BACKGROUND

The purpose of this study was to assess the level of air contamination with bacteria after surgical hydrodebridement and to determine the effectiveness of hydro surgery on bacterial reduction of a simulated infected wound.

METHODS

Four porcine samples were scored then infected with a broth culture containing a variety of organisms and incubated at 37 degrees C for 24 hours. The infected samples were then debrided with the hydro surgery tool (Versajet, Smith and Nephew, Largo, Florida, USA). Samples were taken for microbiology, histology and scanning electron microscopy pre-infection, post infection and post debridement. Air bacterial contamination was evaluated before, during and after debridement by using active and passive methods; for active sampling the SAS-Super 90 air sampler was used, for passive sampling settle plates were located at set distances around the clinic room.

RESULTS

There was no statistically significant reduction in bacterial contamination of the porcine samples post hydrodebridement. Analysis of the passive sampling showed a significant (p < 0.001) increase in microbial counts post hydrodebridement. Levels ranging from 950 colony forming units per meter cubed (CFUs/m3) to 16780 CFUs/m3 were observed with active sampling of the air whilst using hydro surgery equipment compared with a basal count of 582 CFUs/m3. During removal of the wound dressing, a significant increase was observed relative to basal counts (p < 0.05). Microbial load of the air samples was still significantly raised 1 hour post-therapy.

CONCLUSION

The results suggest a significant increase in bacterial air contamination both by active sampling and passive sampling. We believe that action might be taken to mitigate fallout in the settings in which this technique is used.

The diabetic rapid response acute foot team: 7 essential skills for targeted limb salvage

OBJECTIVE

People with diabetes are prone to develop lower-extremity ulcerations and infections, both of which serve as major risk factors for limb amputation. The development of lower-extremity complications of diabetes is associated with increased morbidity and mortality. Recently, there has been increasing interest in the development of interdisciplinary teams to manage the myriad factors that complicate the treatment of high-risk patients, particularly in the perihospitalization period.

METHODS

This article presents 7 essential skills that necessarily allow the limb salvage team to appropriately manage the most common presenting comorbidities in patients with diabetes, including vasculopathy, infection, and deformity.

RESULTS

Seven essentials skills have been demonstrated to promote the greatest salvage outcomes, and these are the ability to (1) perform hemodynamic and anatomic vascular assessment with revascularization, as necessary; (2) perform neurologic workup; (3) perform site-appropriate culture technique; (4) perform wound assessment and staging/grading of infection and ischemia; (5) perform site-specific bedside and intraoperative incision and debridement; (6) initiate and modify culture-specific and patient-appropriate antibiotic therapy; and (7) perform appropriate postoperative monitoring to reduce risk of reulceration and infection.

CONCLUSIONS

Utilization of these 7 essential skills as the core basis for interdisciplinary limb salvage team models will provide clinicians guidance when establishing such teams. Interdisciplinary teams have been demonstrated to improve quality and efficiency of patient care, thus improving overall outcomes and reducing amputation rates.

Current concepts in imaging diabetic pedal osteomyelitis

Diabetic pedal osteomyelitis is primarily a manifestation of vascular insufficiency with resultant tissue ischemia, neuropathy, and infection. Nearly all cases of pedal osteomyelitis arise from a contiguous ulcer and soft tissue infection. MR imaging is the modality of choice to assess for the presence of osteomyelitis and associated soft tissue complications, to guide patient management, and to aid in limited limb resection.

Implementation of diabetic foot ulcer classification system for research purposes to predict lower extremity amputation

BACKGROUND

Patients with diabetic foot ulcers are at a high risk of having both minor or major lower extremity amputations.

AIM

To identify the extent of risk factors for major and minor amputations in patients with diabetic foot ulcers.

MATERIALS AND METHODS

This prospective study was conducted from 2003 to 2005. Using the guidelines for wound classification developed by the International Consensus of the Diabetic Foot, patients were assessed for ischemia, neuropathy, linear measurement of wound diameters, depth of wound, and infection. In addition, end stage renal failure was added as a criterion to assess the association of all these criteria with both toe and lower extremity amputation.

RESULTS

2,321 patients were studied and their mean age was 55 +/- 12 years. Most (83.5%) of the patients presented with foot ulcers (n = 1394). Plantar ulcers were the most common (42.6%) followed by ulcers of the big toe (39%). Some (28.5%) of the patients had different types of amputations: 10% had major lower extreme amputation (MLEA) with 8.7% amputations being below the knee and minor (toe) amputations accounting for 18.5%. The most commonly amputated (9.9%) toe was the first toe.

CONCLUSION

The guidelines for wound classification proposed by the International Consensus of the Diabetic Foot are reliable predictive factors and can determine the outcome of diabetic foot management. Significant factors associated with MLEA were ischemia, neuropathy, and end-stage renal disease and those associated with toe amputation were neuropathy, depth of wound, and grade of infection.

Negative pressure therapy (vacuum) for wound bed preparation among diabetic patients: case series

CONTEXT

Complications from diabetes mellitus affecting the lower limbs occur in 40 to 70% of such patients. Neuropathy is the main cause of ulceration and may be associated with vascular impairment. The wound evolves with necrosis and infection, and if not properly treated, amputation may be the end result. Surgical treatment is preferred in complex wounds without spontaneous healing. After debridement of the necrotic tissue, the wound bed needs to be prepared to receive a transplant of either a graft or a flap. Dressings can be used to prepare the wound bed, but this usually leads to longer duration of hospitalization. Negative pressure using a vacuum system has been proposed for speeding up the treatment. This paper had the objective of analyzing the effects of this therapy on wound bed preparation among diabetic patients.

CASE SERIES

Eighty-four diabetic patients with wounds in their lower limbs were studied. A commercially available vacuum system was used for all patients after adequate debridement of necrotic tissues. For 65 patients, skin grafts completed the treatment and for the other 19, skin flaps were used. Wound bed preparation was achieved over an average time of 7.51 days for 65 patients and 10 days for 12 patients, and in only one case was not achieved.

CONCLUSIONS

This experience suggests that negative pressure therapy may have an important role in wound bed preparation and as part of the treatment for wounds in the lower limbs of diabetic patients.

Novel antibiotics for the management of diabetic foot infections

Foot infections are a major cause of morbidity in diabetic patients. Staphylococcus aureus is the most important pathogen in mild infections; moderate to severe infections are frequently polymicrobial. Multidrug resistance is an increasing problem in isolates from diabetic feet. Worldwide, up to 30% of patients with diabetic foot infection (DFI) are colonised with methicillin-resistant S. aureus (MRSA), whilst extended-spectrum beta-lactamase-producing Gram-negative bacteria are also common in some countries. This emergence of drug resistance has coincided with the launch or imminent availability of many new antibiotics. Most of these were developed to target multidrug-resistant Gram-positive bacteria, although some have a spectrum of activity that includes Gram-negative bacteria and anaerobes. There is a variable amount of experience with these agents in treating skin and skin-structure infections (SSSIs), especially for DFI. However, at least some have a spectrum of activity and/or pharmacological properties that suggest that they may be of value in managing DFIs. The aim of this paper is to review evidence for the efficacy of new antibiotics in the management of SSSIs, including any data relating specifically to the diabetic foot, and to consider where they might fit into the therapeutic armory against DFI.

Phagocytic activity of neutrophils improves over the course of therapy of diabetic foot infections

AIMS

The aim of this study was to investigate changes in phagocytic activity of neutrophils of type 2 diabetic patients with foot infections over short treatment courses. The potential utility of the phagocytic index in determining the efficacy of treatment modalities and it's relationship with metabolic control parameters were evaluated.

METHODS

The phagocytic activity of neutrophils was determined in blood samples of 38 type 2 diabetic patients with foot infections (14 women and 24 men). Mean age and mean duration of diabetes were 66.3+/-9.4 and 19.1+/-11.2 (yrs), respectively. All patients received standard treatment (intensive insulin therapy, antibiotherapy, hyperbaric oxygen therapy and surgical debridement). Phagocytic activity of neutrophils was determined by a standard method. Phagocytic activity of neutrophils, acute phase proteins (C-reactive protein) and glycosylated haemoglobin was determined before therapy and two weeks later.

RESULTS

The phagocytic index before and after therapy were 47.7+/-11.4 and 62.5+/-15.6, respectively (p<0.05). There was a significant correlation between phagocytic index and both CRP and HbA1c (r=0.52, p<0.05 and r=-0.41, p<0.05, respectively).

CONCLUSIONS

Derangement of carbohydrate metabolism may underlie the impairment of bactericidal activity of neutrophils of poorly controlled diabetic patients. These data reveal that phagocytic activity improves during short-course standard therapy and might enable monitoring of efficacy of treatment modalities in diabetic patients with foot infections.

Surgical management of diabetic foot infections and osteomyelitis

Foot ulceration and subsequent infection are a major complication of diabetes mellitus. Without proper diagnosis and treatment, these infections often lead to amputation. A multidisciplinary team approach is essential to maximize outcomes in the attempt to limit amputation and decrease patient morbidity. Mild to moderate diabetic foot infections often respond favorably to local wound care, offloading, and antibiotic therapy. When conservative measures fail or when faced with limb- or life-threatening infection, surgical intervention, whether it be incision and drainage or possible amputation, is warranted. The authors review underlying pathophysiology of diabetic foot infections and an evidenced-based approach to surgical management, with additional emphasis on treatment of osteomyelitis.

Émergence des infections monomicrobiennes à staphylocoque doré méticilline-résistant dans les ostéites du pied diabétique

OBJECTIVE

Describe the clinical appearance, microorganisms involved, and prognosis of diabetic foot osteomyelitis.

METHOD

Retrospective study of 48 patients seen in 2004 for presumed osteomyelitis (exposed bone or suggestive radiographic or clinical picture). Specimens for culture came from swabs of wound discharge, needle aspiration and bone biopsy.

RESULTS

Forty-eight patients with diabetes and contiguous osteomyelitis of the foot were followed for a year. The principal microorganisms isolated were Staphylococcus aureus (58%) and Gram-negative bacilli (29%); 58% of the infections were monomicrobial, 31% of the microorganisms multidrug-resistant, and 85% of the patients were hospitalized, for a median duration of 30 days. Healing occurred in 40 patients, although 15 required amputation first, and 18 had a new infection at a different site (11 involving osteomyelitis) in the year after antibiotic treatment ended.

PERSPECTIVES

Diabetic foot osteomyelitis is a serious disease in view of its site and the microorganisms involved, which are often multidrug-resistant. There is a clear predominance of S. aureus. Medical treatment has an increasingly important role in its management and requires that samples be properly collected for bacteriological testing. The prognosis for these infections, which remains grim in view of the amputation rate and the high risk of new infection, could be improved by reinforcing prevention measures.

Probe-to-bone test for diagnosing diabetic foot osteomyelitis: reliable or relic?

OBJECTIVE

We sought to assess the accuracy of the probe-to-bone (PTB) test in diagnosing foot osteomyelitis in a cohort of diabetic patients with bone culture proven disease.

RESEARCH DESIGN AND METHODS

In this 2-year longitudinal cohort study, we enrolled 1,666 consecutive diabetic individuals who underwent an initial standardized detailed foot assessment, followed by examinations at regular intervals. Patients were instructed to immediately come to the foot clinic if they developed a lower-extremity complication. For all patients with a lower-extremity wound, we compared the results of the PTB test with those of a culture of the affected bone. We called PTB positive if the bone or joint was palpable and defined osteomyelitis as a positive bone culture.

RESULTS

Over a mean of 27.2 months of follow-up, 247 patients developed a foot wound and 151 developed 199 foot infections. Osteomyelitis was found in 30 patients: 12% of those with a foot wound and 20% in those with a foot infection. When all wounds were considered, the PTB test was highly sensitive (0.87) and specific (0.91); the positive predictive value was only 0.57, but the negative predictive value was 0.98.

CONCLUSIONS

The PTB test, when used in a population of diabetic patients with a foot wound among whom the prevalence of osteomyelitis was 12%, had a relatively low positive predictive value, but a negative test may exclude the diagnosis.

Emergency Management of Chronic Wounds

As America's emergency departments witness an increase in care provided to an aging population, the emergency physician increasingly evaluates and treats manifestations of chronic disease. Nonhealing wounds are often a presenting manifestation of chronic disease. They are a source of pain and disability for this population. Emergency physicians should possess a fundamental knowledge in the management of chronic wounds. This article familiarizes the emergency physician with the epidemiology of chronic wounds, the physiology of tissue repair, the pathophysiology involved in wound healing failure, the common types of chronic wounds, and specific management strategies.

Complex wounds

Complex wound is the term used more recently to group those well-known difficult wounds, either chronic or acute, that challenge medical and nursing teams. They defy cure using conventional and simple "dressings" therapy and currently have a major socioeconomic impact. The purpose of this review is to bring these wounds to the attention of the health-care community, suggesting that they should be treated by multidisciplinary teams in specialized hospital centers. In most cases, surgical treatment is unavoidable, because the extent of skin and subcutaneous tissue loss requires reconstruction with grafts and flaps. New technologies, such as the negative pressure device, should be introduced. A brief review is provided of the major groups of complex wounds--diabetic wounds, pressure sores, chronic venous ulcers, post-infection soft-tissue gangrenes, and ulcers resulting from vasculitis.

Diabetic foot disorders. A clinical practice guideline (2006 revision)

The prevalence of diabetes mellitus is growing at epidemic proportions in the United States and worldwide. Most alarming is the steady increase in type 2 diabetes, especially among young and obese people. An estimated 7% of the US population has diabetes, and because of the increased longevity of this population, diabetes-associated complications are expected to rise in prevalence. Foot ulcerations, infections, Charcot neuroarthropathy, and peripheral arterial disease frequently result in gangrene and lower limb amputation. Consequently, foot disorders are leading causes of hospitalization for persons with diabetes and account for billion-dollar expenditures annually in the US. Although not all foot complications can be prevented, dramatic reductions in frequency have been achieved by taking a multidisciplinary approach to patient management. Using this concept, the authors present a clinical practice guideline for diabetic foot disorders based on currently available evidence, committee consensus, and current clinical practice. The pathophysiology and treatment of diabetic foot ulcers, infections, and the diabetic Charcot foot are reviewed. While these guidelines cannot and should not dictate the care of all affected patients, they provide evidence-based guidance for general patterns of practice. If these concepts are embraced and incorporated into patient management protocols, a major reduction in diabetic limb amputations is certainly an attainable goal.

The role of early surgical debridement and revascularization in patients with diabetes and deep foot space abscess: retrospective review of 106 patients with diabetes

One hundred-six patients underwent emergency debridement of a deep foot space abscess. While 43 patients were admitted after an outpatient visit with immediate surgical debridement (group A), 63 patients were transferred from other hospitals after a mean stay of 6.2+/-7.5 days without debridement (group B). No significant differences were observed in the demographic and clinical features between the 2 groups, except for the following differences in group B: higher blood glucose level on admission (P=.015), lower serum albumin level (P=.005), and a more frequent extension of the infection to the heel (P=.005). Eradication of the infection was obtained in group A without amputation in 9 patients, with an amputation of 1 or more rays in 21, with metatarsal amputations in 12, and with a Chopart amputation in 1. In group B, incision and drainage alone were performed in 4 patients, amputation of 1 or more rays in 21, metatarsal amputations in 10, Chopart amputations in 23, and an above-the-ankle amputation in 5. The amputation level was significantly more proximal in group B (chi2=24.4, P<.001). There was no significant difference in the presence of peripheral arterial occlusive disease between the 2 groups (P=.841). Regression logistic analysis showed a significant relationship between the amputation level and the number of days elapsed before debridement (odds ratio, 1.61; P=.015; confidence interval, 1.10-2.36), but not with the presence of peripheral occlusive disease (odds ratio, 1.73; P=.376; confidence interval, 0.29-15.3). These data show that a delay in the surgical debridement of a deep space abscess increases the amputation level. Accuracy in the diagnosis of peripheral occlusive disease and immediate revascularization yield similar outcomes in patients with or without peripheral occlusive disease.