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

Results

Of the 106 patients included in this study, 42 presented within 3 days of wound development, 20 patients presented within 3 to 7 days after wound development, and 44 patients presented 7 days after wound development. All patients were reviewed at 2 weeks, 4 weeks, 6 weeks, and 8 weeks, and thereafter as necessary.

The average patient age was 62 years (range, 49–77 years), with 78 males and 28 females. A total of 21 patients required minor debridement, and 18 required major debridement. Of those who required toe amputation, 35 patients required single toe amputation and 19 patients required multiple toe amputations. Forefoot amputation was required in 7 patients, and 2 patients underwent below-knee amputation. Of note, 4 patients were treated for necrotizing fasciitis (Table 2). Patients were managed postoperatively by means of skin grafting, regular dressing changes, delayed wound closure, or negative pressure wound therapy followed by skin grafting (Table 3). All patients were given calcium sulfate beads mixed with antibiotics as part of the treatment pathway. The beads were mixed with meropenem in 64 cases, colistin in 35 cases, and vancomycin in 7 cases. The volume of implanted beads ranged from 5 cc to 20 cc depending on the size of the wound cavity. The beads were packed into the wound and around any remaining bone to ensure thorough coverage and mitigate any dead space. No systemic adverse reactions to the local delivery of antibiotics were observed in this study.

In patients with positive culture, a total of 7 major organisms were isolated (Table 4). The most common of these organisms were Pseudomonas aeruginosa (n = 72) and Klebsiella pneumoniae (n = 70). Cultures from 78 patients indicated the presence of multiple organisms. At final follow-up, 92% of the patients (98/106) had no recurrence of infection (mean follow-up, 10 weeks [range, 6–16 weeks]). A total of 8 patients required repeat outpatient minor debridement of the same wound for clearance of slough. Of the 18 patients who required skin grafting for wound closure, small ulcers developed at the junction of normal skin and graft in 5 patients. However, these were "clean" ulcers that were managed with regular dressing changes.

A summary of average healing times by procedure is noted in Table 5. Patients who underwent minor or major debridement followed by the application of calcium sulfate beads mixed with antibiotics healed on average in 47 days and 64 days, respectively. The average duration of wound healing following a single toe amputation or multiple toe amputations was 50 days and 65 days, respectively. Patients who were treated for wounds associated with necrotizing fasciitis had the longest time to wound healing, with an average of 90 days (Table 5). This investigation demonstrates that a wide range of antibiotics can be incorporated into calcium sulfate beads and retain their potency against many common pathogens, including Pseudomonas and Staphylococcus (Figures 1–4).

Figure 1.

Case 1. A 64-year-old male with a history of type 2 diabetes mellitus presented with gangrene of the great toe of the left foot. Gangrene had persisted for 5 days. (A) Clinical photograph of the gangrenous great toe. Deep tissue sent for culture sensitivity exhibited growth of Pseudomonas aeruginosa. (B) Prior to closure, calcium sulfate was mixed with 500 mg meropenem and the resulting beads were embedded in the wound. (C) The wound was closed with silk sutures. (D) Follow-up photograph obtained at 2 months showing wound healing.

Figure 2.

Case 2. A 48-year-old male with a history of diabetes presented with a wound over the first metatarsophalangeal joint of the right foot. (A) Clinical photograph showing visible discharge from the wound. Deep tissue sent for culture sensitivity showed growth of Staphylococcus aureus and Klebsiella pneumoniae, which were sensitive to co-trimoxazole and colistin, respectively. (B) A deep cavity at the first metatarsophalangeal joint was identified intraoperatively. Calcium sulfate was mixed with 3 MU colistin, and the resulting beads were placed into the wound site. (C) Follow-up photograph obtained 6 weeks postoperatively showing complete wound healing.

Figure 3.

Case 3. A 61-year-old male with a history of type 2 diabetes mellitus presented with abscess of the plantar aspect of the left foot. The abscess had persisted for 4 days. (A) Abscess of the left foot was debrided, and the cavity was shown. Culture sensitivity showed growth of methicillin-resistant Staphylococcus aureus, which was sensitive to vancomycin. (B) Calcium sulfate was mixed with 1 g vancomycin, and the resulting beads were embedded in the wound. (C) Follow-up photograph obtained at 7 weeks showing healed wound. (D) Radiograph showing wound healing at the 7-week follow-up.

Figure 4.

Case 4. A 71-year-old male with a history of type 2 diabetes mellitus presented with abscess of the plantar aspect of the right foot. The abscess had persisted for 3 days. Culture sensitivity showed growth of Escherichia coli, which was sensitive to meropenem. (A) The abscess was debrided, calcium sulfate was mixed with 1 g meropenem, and the resulting beads were embedded in the wound. (B) Good granulation tissue was visible after 8 weeks. (C) Split-thickness skin grafting. (D) Appearance of healing 4 weeks after skin grafting.

processing....