Role of STIMULAN in chronic osteomyelitis-A randomised blinded study on 95 patients comparing 3 antibiotic compositions, bead quality, forming & absorption time.

Introduction: Chronic Osteomyelitis is a well-known clinical entity affecting patients holistically and presents with multiple treatment challenges. Local antibiotic delivery with biodegradable drug carriers has shown promising results.

Materials And Methods: Prospective multicenter study performed at 2 centers from November 2021 to January 2023 on 95 osteomyelitis patients treated with surgical debridement & STIMULAN™ for local antibiotic delivery. Patients were randomized into 3 groups. Authors compared antibiotic combinations, bead quality, bead setting, and resorption time for calcium sulfate beads- STIMULAN™. Additionally, organisms isolated, WBC Turnover time, Hypersensitivity Reactions, Recurrence, and Revision Rates were documented.

Results: 95 patients underwent surgical debridement and STIMULAN™ bead application for chronic osteomyelitis. The proximal 1/3rd tibia was commonly affected. The most common symptoms were sinus and pus discharge in 96.84 % & 86.31 % of patients respectively (p < 0.001). & MRSA were isolated in 37.8 % & 29.4 % of the patient's wound culture respectively. Bead setting time in Descending order was Group 3 > Group 2 > Group 1 (p < 0.001). Bead setting first in Group 1 followed by Group 3 & 2. On compression, Group-1 beads withstood maximum compression forces & had smooth even bead surfaces. On radiographs, 1/3rd bead volume in ascending order was Group 3 > Group 2 > Group 1 (p < 0.001). 2/3rd reduction in ascending order was Group 3 > Group 2 > Group 1. Complete bead absorption was earliest seen in Group 3 followed by Group 2 & Group 1 (p < 0.001). Recurrence in 2 patients (Group 2) at 6 weeks. Revision rate: 2.10 %. There were no incidences of hypersensitivity. Suture removal was done at 16 ± 2 days.

Conclusion: STIMULAN™ combination with tobramycin, vancomycin, and gentamycin is stable, and forms uniform beads with predictable drug elution & bead resorption with negligible side effects. A mixture with higher liquid content sets later, forms softer beads, and resorbs earlier.