Surgical treatment of limb- and life-threatening infections in the feet of patients with diabetes and at least one palpable pedal pulse: successes and lessons learnt

Surgical Diabetic Foot Infections: Is Osteomyelitis Associated With a Worse Prognosis?

It has been reported that patients with diabetes and foot ulcers complicated with osteomyelitis (OM) have a worse prognosis than those complicated with soft tissue infections (STI). Our study aimed to determine whether OM is associated with a worse prognosis in cases of moderate and severe diabetic foot infections requiring surgery. A retrospective series consisted of 150 patients who underwent surgery for diabetic foot infections. We studied the differences between OM versus STI. Furthermore, diabetic foot infections were reclassified into four groups: moderate STI (M-STI), moderate OM (M-OM), severe STI (S-STI), and severe OM (S-OM). The variables associated with prognosis were limb loss, length of hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing (both the initial ulcer and the postoperative wound). No differences in limb salvage, hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing were found when comparing OM with STI. Patients with M-O had a higher rate of recurrences after initial treatment and a longer time to healing when comparing with M-STI. We didn't find any differences between severe infections with or without OM. In conclusion, we have found in our surgical series of diabetic foot infections that OM is not associated with worse prognosis when comparing with STI regarding limb loss rate, length of hospital stays, duration of antibiotic treatment, recurrence of the infection, and time to healing. The results of the present series should further be confirmed by other authors.

Meta-Analysis: Outcomes of Surgical and Medical Management of Diabetic Foot Osteomyelitis

BACKGROUND

The aim of this study was to evaluate clinical outcomes in the published literature on medical and surgical management of diabetic foot osteomyelitis (DFO).

METHODS

A PubMed and Google Scholar search of articles relating to DFO was performed over the dates of January 1931 to January 2020. Articles that involved Charcot arthropathy, case reports, small case series, review articles, commentaries, nonhuman studies, and non-English articles were excluded. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used to rate the bias of each study. A meta-analysis was performed using random-effects and inverse variance methods. The search yielded 1192 articles. After review and the removal of articles that did not meet inclusion criteria, 28 articles remained. Eighteen articles were related to the medical management of DFO and 13 articles were related to surgical management. Three articles looked at a combination of medical and surgical management and were included in both groups. Heterogeneity was evaluated using Cochran Q, I 2, τ2, and τ.

RESULTS

The average success rate was 68.2% (range, 17.0%-97.3%) for medical treatment and 85.7% (range, 65.0%-98.8%) for surgical and medical treatment. There were significant inconsistencies in accounting for peripheral arterial disease and peripheral neuropathy. There was significant heterogeneity in outcomes between studies. However, there was a high rate of successful treatment and a wide range between patients with medical treatment and combined surgical and medical treatment.

CONCLUSIONS

Additional properly designed prospective studies with gold-standard references for diagnosing osteomyelitis are needed to help determine whether medical management of DFO can be successful without surgical intervention.

Limb Salvage in Severe Diabetic Foot Infection

Severe diabetic foot infections (DFI) are both limb threatening and life threatening and associated with negative impact on health-related quality of life. Most severe DFIs require surgical intervention, and the goal of treatment should be preservation of limb function in addition to eradication of infection. Minor amputations are required in approximately 40% and major amputations in approximately 20% of patients. Significant risk factors for lower extremity amputation included male gender, smoking, previous amputation, osteomyelitis, peripheral artery disease, retinopathy, severe infections, gangrene, neuroischemic diabetic foot infections, leukocytosis, positive wound cultures, and isolation of gram-negative bacteria.

Are Surrogate Markers for Diabetic Foot Osteomyelitis Remission Reliable?

BACKGROUND

We aimed to evaluate surrogate markers commonly used in the literature for diabetic foot osteomyelitis remission after initial treatment for diabetic foot infections (DFIs).

METHODS

Thirty-five patients with DFIs were prospectively enrolled and followed for 12 months. Osteomyelitis was determined from bone culture and histologic analysis initially and for recurrence. Fisher exact and χ2 tests were used for dichotomous variables and Student t and Mann-Whitney U tests for continuous variables (α = .05).

RESULTS

Twenty-four patients were diagnosed as having osteomyelitis and 11 as having soft-tissue infections. Four patients (16.7%) with osteomyelitis had reinfection based on bone biopsy. The success of osteomyelitis treatment varied based on the surrogate marker used to define remission: osteomyelitis infection (16.7%), failed wound healing (8.3%), reulceration (20.8%), readmission (16.7%), amputation (12.5%). There was no difference in outcomes among patients who were initially diagnosed as having osteomyelitis versus soft-tissue infections. There were no differences in osteomyelitis reinfection (16.7% versus 45.5%; P = .07), wounds that failed to heal (8.3% versus 9.1%; P = .94), reulceration (20.8% versus 27.3%; P = .67), readmission for DFIs at the same site (16.7% versus 36.4%; P = .20), amputation at the same site after discharge (12.5% versus 36.4%; P = .10). Osteomyelitis at the index site based on bone biopsy indicated that failed therapy was 16.7%. Indirect markers demonstrated a failure rate of 8.3% to 20.8%.

CONCLUSIONS

Most osteomyelitis markers were similar to markers in soft-tissue infection. Commonly reported surrogate markers were not shown to be specific to identify patients who failed osteomyelitis treatment compared with patients with soft-tissue infections. Given this, these surrogate markers are not reliable for use in practice to identify osteomyelitis treatment failure.

Long-term Mortality of a Cohort of Patients Undergoing Surgical Treatment for Diabetic Foot Infections. An 8-year Follow-up Study

We analyzed a retrospective cohort of 150 patients with diabetic foot infections (DFIs) who underwent surgical treatment to determine long-term outcomes. The median follow-up of the series was 7.6 years. Cox's proportional hazards model for survival time was performed and hazard ratios (HRs) were estimated. Survival times were plotted using the Kaplan-Meier method. Fifteen patients (10%) required readmission after discharge from the hospital for a recurrence of the infection. Ninety patients (60%) had re-ulcerations. Forty-nine (54.4% of those re-ulcerated) required new admission and 24 of them (26.6% of those re-ulcerated) finally required a new amputation. Overall cumulative survival rates at 1, 5, and 8 years were 95%, 78%, and 64%, respectively. Predictive variables of long-term mortality were insulin treatment (HR: 2.0, 95% CI: 1.1-3.6, P = .01), female sex (HR: 3.1, 95% CI: 1.7-5.3, P<.01) and estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m² (HR: 2.2, 95% CI: 1.1-4.2, P = .01). In conclusion, patients undergoing surgical treatment for DFIs had a high rate of recurrences and mortality. Women, patients who underwent treatment with insulin, and those with eGFR <60 ml/min/1.73 m² had a higher risk of long-term mortality.

Meta-analysis of risk factors for amputation in diabetic foot infections

BACKGROUND

Knowledge of risk factors is crucial to develop management and treatment protocols for the prevention of lower extremity amputation for patients with diabetic foot infections (DFIs).

METHODS

We searched the research literature for studies reporting risk factors for lower extremity amputation in patients with DFI. The main outcome variables included both minor and major amputations. This study was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, and the protocol was registered in PROSPERO (CRD42018118543).

RESULTS

A total of 2471 potential articles from the database search met the inclusion criteria. After reviewing the titles, abstracts, and full texts, remaining 25 articles were included in the final analysis. We identified 6132 patients with DFI in the 25 included articles. Of these, 1873 patients who underwent amputation were investigated. Male gender (odds ratio [OR]: 1.31), smoking (OR: 1.38), history of amputation (OR: 1.47), history of osteomyelitis (OR: 1.94), peripheral arterial disease (OR: 2.35), retinopathy (OR: 1.32), International Working Group on the Diabetic Foot (IWGDF) grades 3 and 4 (OR: 1.7 and 2.5), Wagner grades 4 and 5 (OR: 4.3 and 6.4), gangrene/necrosis (OR: 9.9), osteomyelitis (OR: 4.5), neuroischaemic DFI (OR: 3.06), severe infection (OR: 3.12), length of hospitalization (standardized mean difference [SMD]: 0.7), leukocytosis (OR: 1.76), mean erythrocyte sedimentation rate (ESR) (SMD: 0.5), mean C-reactive protein (CRP) (SMD: 0.8), tissue culture positivity (OR: 1.61), and isolation of Gram-negative bacteria from tissue culture (OR: 1.5) were found as predictors of amputation in DFI.

CONCLUSIONS

The present study highlighted some differences in diabetic foot ulcers and DFIs in terms of risk factors for lower extremity amputation. These data provide detailed information about risk factors for amputations among patients with DFI, thus contributing to the creation of new classification systems for assessment of high-risk patients.

Lower Extremity Necrotizing Fasciitis in Diabetic and Nondiabetic Patients: Mortality and Amputation

Lower extremity necrotizing fasciitis (NF) is a severe infection requiring immediate surgery. The aim of this study was to assess patient factors predictive of amputation and mortality in diabetes mellitus (DM) and non-DM patients with lower extremity NF. The American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database was reviewed retrospectively. Out of 674 patients with lower extremity NF, 387 had DM (57.4%). Patients with DM had lower mortality ( P = .004). Increased mortality was independently associated with age >60 years (adjusted odds ratio [aOR] = 3.96, 95% confidence interval [CI] = 1.69-9.77), partial thromboplastin time >38 seconds (aOR = 2.66, 95% CI = 1.09-6.62), albumin <2.0 mg/dL (aOR = 2.84, 95% CI = 1.13-7.37), coagulopathy (aOR = 3.29, 95% CI = 1.24-9.19), higher anesthesia risk category (aOR = 3.08, 95% CI = 1.18, 8.59), chronic obstructive pulmonary disease (aOR = 3.46, 95% CI = 1.13-10.9), postoperative acute respiratory distress syndrome (aOR = 5.24, 95% CI = 2.04-14.4), and postoperative septic shock (aOR = 5.14, 95% CI = 1.94-14.1). Amputation was independently associated with DM (aOR = 4.35, 95% CI = 2.63-7.35) but not mortality. Although DM was associated with more amputations for lower extremity NF, patients with DM had lower mortality than non-DM patients in the bivariate analysis. Further research is needed to investigate outcomes among DM and non-DM patients in the context of lower extremity NF.

Evidence based review of literature on detriments to healing of diabetic foot ulcers

BACKGROUND

Diabetes mellitus places a substantial burden on society worldwide. Diabetic foot ulcers are a challenging problem for clinicians. Seven generally accepted detriments to healing of diabetic foot ulcers were identified: infection, glycaemic control, vascular supply, smoking, nutrition, deformity and offloading. The aim of this paper is to present a comprehensive evidence based review of the literature available on detriments to healing of diabetic foot ulcers.

METHOD

A research question was generated for each of the detriments to healing and a comprehensive review of the literature was performed using the Pubmed database in July 2014. All articles were assessed for relevancy and a level of evidence was assigned. An analysis of the total body of literature was used to assign a grade of recommendation to each detriment.

RESULTS

Grade A recommendation was assigned to offloading as there was good evidence supporting this intervention. Grade B recommendation was assigned to deformity as there was fair evidence consistent with the hypothesis. Infection and vascular supply had poor quality evidence supporting the research question and grade C recommendation was assigned. Grade I recommendation was assigned to glycaemic control, smoking and nutrition as there was insufficient and conflicting evidence available.

CONCLUSION

Our literature review revealed good evidence for some factors and insufficient literature on others. Further studies are needed to provide quality evidence regarding detriments to healing of diabetic ulcers.

Antibiotic Resistance in Diabetic Foot Soft Tissue Infections: A Series From Greece

Diabetic foot infections are a common and serious problem for all health systems worldwide. The aim of this study was to examine the resistance to antibiotics of microorganisms isolated from infected soft tissues of diabetic foot ulcers, using tissue cultures. We included 113 consecutive patients (70 men, 43 women) with a mean age of 66.4 ± 11.2 years and a mean diabetes duration of 14.4 ± 7.6 years presenting with diabetic foot soft tissue infections. Generally, no high antibiotic resistance was observed. Piperacillin-tazobactam exhibited the lowest resistance in Pseudomonas, as well as in the other Gram-negative pathogens. In methicillin-resistant Staphylococcus aureus isolates, there was no resistance to anti-Staphylococcus agents. Of note, clindamycin, erythromycin, and amoxycillin/clavulanic acid exhibited high resistance in Gram-positive cocci. These results suggest that antibiotic resistance in infected diabetic foot ulcers in our area is not high and they are anticipated to prove potentially useful in the initial choice of antibiotic regimen.

Outcomes after foot surgery in people with a diabetic foot ulcer and a 12-month follow-up

OBJECTIVE

The aim of this study was to retrospectively measure the outcomes of foot-sparing surgery at one year follow-up for patients with diabetic foot ulcers (DFUs). We assessed wound healing and the need for further surgery in relation to the variables that influence healing.

METHOD

Data were retrospectively collected by reviewing the electronic files of patients attending the Wound Expert Clinic (WEC). Outcomes of surgical debridement, toe, ray and transmetatarsal amputations were assessed.

RESULTS

A total of 129 cases in 121 patients were identified for inclusion. The results demonstrated that complete wound healing was reached in 52% (61/117) of the patients within 12 months. The need for additional surgery or for major amputation was 56% (n=72/129) and 30% (n=39/129) respectively. The need for an additional procedure was particularly high after surgical debridement (75%, 33/44) and transmetatarsal amputation (64%, 7/11). Risk factors for non-healing or for a major amputation were: infection (p=0.01), ischaemia (p=0.01), a history of peripheral arterial occlusive disease (p<0.01) and smoking (p=0.01). Additional findings were that not all patients underwent vascular assessment and in half of the patients there was a delay in undergoing revascularisation.

CONCLUSION

The results of the study reveal some areas for improvement including timely revascularisation and performance of multiple debridement procedures if needed in order to save a limb.

Efficacy of a New Heparan Sulfate Mimetic Dressing in the Healing of Foot and Lower Extremity Ulcerations in Type 2 Diabetes: A Case Series

A novel heparan sulfate glycosaminoglycan mimetic product for local application to promote wound healing (CACIPLIQ) has recently become available. It is a biophysical therapeutic product comprising a polysaccharide as an innovative biomaterial to accomplish mechanical tissue engineering and skin regeneration in the site of ulceration. We present a series of 12 patients with type 2 diabetes (4 men and 8 women; age 53-87 years; diabetes duration 8-25 years) having chronic resistance to therapy for foot and lower extremity ulcerations. CACIPLIQ was locally applied twice per week after careful debridement. Complete ulcer healing was accomplished in all patients after a mean treatment duration of 4.92 months (range = 2-12 months). The product was very well tolerated. In conclusion, these results, although preliminary, are encouraging and suggest adequate efficacy and safety of the new product in difficult-to-heal foot and lower extremity ulcerations in type 2 diabetes.

Safety and Effectiveness of Therapeutic Magnetic Resonance in the Management of Postsurgical Lesion of the Diabetic Foot

To evaluate the safety and effectiveness of therapeutic magnetic resonance (TMR) in the management of the diabetic foot (DF), we treated a group of consecutive type 2 diabetic inpatients with wide postsurgical lesions (Group A: N = 10; age 67.7 ± 18.9 years, duration of diabetes 22.3 ± 6.6 years, 8.1 ± 1.1%, body mass index 29.4 ± 2.1 kg/m2), for 2 consecutive weeks, while admitted, with a low-intensity magnetic resonance equipment, in addition to standard treatment. Patients, compared with a matched control group with the same clinical characteristics (Group B), were then followed monthly for 6 months to evaluate healing rate (HR), healing time (HT), rate of granulation tissue (GT) at 3 months, and adverse events. HR was of 90% in Group A and 30% in Group B ( P < .05); GT was 73.7 ± 13.2% in Group A versus 51.84 ± 18.77% in Group B ( P < .05). HT in Group A was 84.46 ± 54.38 days versus 148.54 ± 78.96 days in Group B ( P < .01). No difference in adverse events (5 in Group A and 6 in Group B) was observed throughout the study period. In this pilot study, the use of TMR at this dose and duration was safe. The results also permit the observation that TMR plus standard care offered a faster healing rate compared with standard care alone.

SIRS is valid in discriminating between severe and moderate diabetic foot infections

OBJECTIVE

This retrospective, single-center study was designed to distinguish severe diabetic foot infection (DFI) from moderate DFI based on the presence or absence of systemic inflammatory response syndrome (SIRS).

RESEARCH DESIGN AND METHODS

The database of a single academic foot and ankle program was reviewed and 119 patients were identified. Severe DFI was defined as local infection associated with manifestation of two or more objective findings of systemic toxicity using SIRS criteria.

RESULTS

Patients with severe DFI experienced a 2.55-fold higher risk of any amputation (95% CI 1.21-5.36) and a 7.12-fold higher risk of major amputation (1.83-41.05) than patients with moderate DFI. The risk of minor amputations was not significantly different between the two groups (odds ratio 1.02 [95% CI 0.51-2.28]). The odds of having a severe DFI was 7.82 times higher in patients who presented with gangrene (2.03-44.81) and five times higher in patients who reported symptoms of anorexia, chills, nausea, or vomiting (2.22-11.25). The mean hospital length of stay for patients with severe DFI was ∼4 days longer than for patients with moderate DFI, and this difference was statistically significant.

CONCLUSIONS

SIRS is valid in distinguishing severe from moderate DFI in hospitalized patients. Patients with severe DFI, as by manifesting two or more signs of systemic inflammation or toxicity, had higher rates of major amputation and longer hospital stays and required more surgery and more subsequent admissions than patients who did not manifest SIRS.

Influence of the Location of Nonischemic Diabetic Forefoot Osteomyelitis on Time to Healing After Undergoing Surgery

The forefoot has been reported as the most frequent location of osteomyelitis in the feet of patients with diabetes. The forefoot includes toes and metatarsal heads as common locations of bone infections, but the anatomy of these bones is quite different. As a result, such differences in anatomy may have an impact on the outcomes. The aim of the present study was to determine whether different locations of osteomyelitis in the forefoot have any influence on time to healing after undergoing surgery in a prospective series including 195 patients without peripheral arterial disease and osteomyelitis confirmed by histopathology. Location of the lesion was classified into 4 groups: hallux, first metatarsal head, lesser metatarsal heads, and lesser toes. The time required to achieve healing and the cumulative rate of wounds healed and likelihood of healing were analyzed at 4, 8, and 12 weeks after surgery. Time of healing (mean ± SD) in the whole series was 10.7 ± 8.4 weeks. Osteomyelitis located in the lesser toes has a higher probability of healing by the fourth week (odds ratio [OR] = 5.7, 95% confidence interval [CI] = 2.8-11.6, P < .001), eighth week (OR = 3.2, 95% CI = 1.6-6.4, P < .001), or twelfth week (OR = 3.1, 95% CI = 1.3-7.0, P = .008) than other osteomyelitis locations. Osteomyelitis located in the first metatarsal joint was less likely to heal by the eighth week (OR = 0.4, 95% CI = 0.2-0.9, P = .037) and 12th week (OR = 0.4, 95% CI = 0.2-1.0, P = .040). In conclusion, time to healing is significantly different according to the location of the bone infection in the forefoot.

Tissue and Swab Culture in Diabetic Foot Infections

We evaluated the diagnostic performance of swabs versus tissue cultures in 28 diabetic patients with neuropathic (group A) and 22 diabetic patients with neuroischemic foot ulcer (group B) and the differences in bacterial isolates between the 2 groups. In group A, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of swab cultures for the diagnosis of infection were 100%, 40%, 88.5%, and 100%, respectively. In group B, the corresponding values were 100%, 22.2%, 65%, and 100%. In group A, sensitivity, specificity, PPV, and NPV of swab cultures for the identification of pathogens were 100%, 14.3%, 53.8%, and 100%, respectively. In group B, the corresponding values were 100%, 18.2%, 55%, and 100%. In each group, Staphylococcus aureus and Pseudomonas aeruginosa were the most common isolates. The number of isolates was significantly higher on swab versus tissue cultures only in group A ( P = .033). No differences were observed between groups in number of isolates and colony forming units. In conclusion, swab cultures are highly sensitive but less specific and have an excellent NPV both in diabetic patients with neuropathic and in those with neuroischemic foot ulcer. There are no differences between the groups in microbial load.

Super-oxidized solution (Dermacyn Wound Care) as adjuvant treatment in the postoperative management of complicated diabetic foot osteomyelitis: preliminary experience in a specialized department

Surgery is usually used to treat diabetic foot osteomyelitis (DFO), whether primarily or in cases in which antibiotics are not able to control infection. In many cases, the bone is only partially removed, which means that residual infection remains in the bone margins, and the wound is left open to heal by secondary intent. The use of culture-guided postoperative antibiotic treatment and adequate management of the wound must be addressed. No trials exist dealing with local treatment in the postoperative management of these cases of complicated DFO. We decided to test a super-oxidized solution, Dermacyn Wound Care (DWC; Oculus Innovative Sciences Netherlands BV, Sittard, Netherlands) to obtain preliminary experience in patients in whom infected bone remained in the surgical wounds. Our hypothesis was that DWC could be useful to control infection in the residual infected bone and surrounding soft tissues and would thus facilitate healing. Fourteen consecutive patients who underwent conservative surgery for DFO, in whom clean bone margins could not be assured, were treated in the postoperative period with DWC. Eleven cases were located in the forefoot, 6 on the first ray and the rest in lesser toes, 1 in the Lisfranc joint, and 2 on the calcaneus. No side effects appeared during treatment. Neither allergies nor skin dermatitis were found. Limb salvage was successfully achieved in 100% of the cases. Healing was achieved in a median period of 6.8 weeks.

Determinants of microbial load in infected diabetic foot ulcers: a pilot study

We examined the determinants of microbial load in infected diabetic foot ulcers in 62 patients (38 men and 24 women, mean age: 65.63 ± 12.71 years) with clinically infected diabetic foot ulcers. Tissue cultures were taken from ulcers by 4 mm punches. Ulcer grade (University of Texas classification), neuropathy disability score (NDS), neuropathy symptom score (NSS), ankle-brachial index (ABI), perfusion, extent, depth, infection, and sensation (PEDIS) grade of diabetic foot infection, and laboratory parameters were evaluated in all patients. Total microbial load was positively correlated with the number of isolates on tissue cultures (r s = 0.544, P < 0.001), white blood cell count (WBC) (r s = 0.273, P = 0.032), and platelet count (PLT) (r s = 0.306, P = 0.015). It also exhibited a borderline insignificant positive correlation with PEDIS infection grade (r s = 0.246, P = 0.053). In stepwise linear regression analysis, the number of isolates on tissue cultures and WBC were identified as the only two significant parameters accounting for 38% of the variation in the log of total microbial load (adjusted R (2) = 0.380, P < 0.001). In conclusion, patients with infected diabetic foot ulcer exhibit a positive correlation of total microbial load with the number of isolates on tissue cultures, WBC and PLT.

From the diabetic foot ulcer and beyond: how do foot infections spread in patients with diabetes?

A diabetic foot infection is usually the result of a pre-existing foot ulceration and is the leading cause of lower extremity amputation in patients with diabetes. It is widely accepted that diabetic foot infections may be challenging to treat for several reasons. The devastating effects of hyperglycemia on host defense, ischemia, multi-drug resistant bacteria and spreading of infection through the foot may complicate the course of diabetic foot infections. Understanding the ways in which infections spread through the diabetic foot is a pivotal factor in order to decide the best approach for the patient's treatment. The ways in which infections spread can be explained by the anatomical division of the foot into compartments, the tendons included in the compartments, the initial location of the point of entry of the infection and the type of infection that the patient has. The aim of this paper is to further comment on the existed and proposed anatomical principles of the spread of infection through the foot in patients with diabetes.