Diabetic Foot Ulcers and Osteomyelitis: Use of Biodegradable Calcium Sulfate Beads Impregnated With Antibiotics for Treatment of Multidrug-Resistant Organisms

Prashant Patil, MCh, FDFS; Rajeev Singh, MS; Apurva Agarwal, MS; Rajiv Wadhwa, MS; Aran Bal, MS, PhD; Sanjay Vaidya, MS, MCh

Disclosures

Wounds. 2021;33(3):70-76. 

In This Article

Materials and Methods

A combined prospective-retrospective review of 106 patients treated at a single tertiary referral center from January 2015 to July 2018 was performed. The average time to follow-up was 92 days (range, 48–158 days). Preoperatively, all patients underwent clinical and radiological evaluation for the presence of infection. Inflammatory markers, including complete blood counts and C-reactive protein levels, were used to provide indirect evidence for the presence of infection. Final confirmation was provided by a tissue biopsy taken during the surgical procedure.

Inclusion Criteria

All patients presenting with type 1 or type 2 diabetes (according to World Health Organization criteria) with DFUs of Wagner grades 2 to 5 were recruited into this study. Also recruited into this study were patients presenting with associated neuropathy or poor peripheral circulation as well as persistent high bacterial counts after debridement requiring prolonged antibiotic therapy. The patients were assessed by a multidisciplinary team, including a podiatrist and an orthopedic surgeon, as well as a vascular surgeon, microbiologist/infectious disease physician, and nephrologist if necessary. Vascular interventionalists and plastic surgeons were also part of the team. Exclusion criteria included patients with either a negative culture or positive cultures for a single bacterial species that was sensitive to oral antibiotics.

Surgical Management

Patients in this study underwent radical debridement. Thorough debridement of any devitalized or infected bone was performed until healthy cancellous and cortical bone was reached. Any infected soft tissue was removed as well, and the infection site irrigated with saline. Deep extracted tissue was sent for culture. Calcium sulfate beads were combined with appropriate antibiotics based on antibiotic susceptibility from microbiological cultures (Table 1). The calcium sulfate paste was prepared according to the instructions for use. The result was antibiotic-impregnated pellets measuring 6 mm in diameter. A total of 28 patients received supplementary oral antibiotics for a period of 2 weeks, as advised by the infectious disease specialist. Empiric, broad-spectrum antibiotics (cefoperazone and sulbactam) were administered until culture reports were obtained. Patients who presented with sepsis or septic shock were given meropenem and tigecycline, with the doses adjusted to the serum creatinine value. After obtaining culture reports, a combination of calcium sulfate beads mixed with the appropriate antibiotic was used. Patients were not given systemic antibiotics along with antibiotic beads after the 2-week postoperative window. Only regular dressing changes were done on follow-up visits. No patient in this study received intravenous (IV) antibiotics.

Data Collection

Patient demographics, comorbidities, etiology of infection, clinical features, diagnostic tests, and antibiotic treatment choice and duration were collected. White blood cell count as well as serum C-reactive protein levels were measured. Ulcer healing was defined as complete skin closure with a normal appearance of the skin without callus. The date at which this stage was reached was used as an end point. Healing time was expressed in days.

Clearance of infection was conducted by clinical assessment of the wound for classic signs and symptoms of infection (redness, heat, swelling). Clearance of infection was also confirmed by serially monitoring wound size, serum creatinine level, and clinical improvement in patient symptoms such as increased appetite or improvements in patients' blood sugar levels.

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