Musculoskeletal Infection Managements | Lecture Note

University:
The University Of Western Ontario
Course:
Biology 2290F | Scientific Method in Biology
Academic year:

2022
Views:

407

Pages:

3
Author:

Kyuwon J.

Musculoskeletal infection managements ● Indication ○ primarily on osteomyelitis either acute or chronic ○ infected orthopedic implants ■ post-ORIF ■ prosthetic joint infections ○ need to eradicate the infection ■ mean while we must also prepare for bone and soft tissue for reconstruction ■ must be done independently ○ with aggressive surgical debridement, beads are now replacing the dead space ■ will give higher local antibiotic concentrations ● materials ○ polymethylmethacrylate (PMMA) beads ■ non-resorbable ■ acrylic cement mixed with antibiotics ■ needs second surgery for removal ○ Antibiotics ■ healing and stability ● Gentamicin ● tobramycin ● vancomycin ■ antibiotic is chosen through culture and sensitivity results ● New resorbable alternatives ○ calcium sulfates beads ■ are able to be resorbed within weeks ■ one surgery is enough for implant ■ mixed with broader range of antibiotics Surgical techniques ● Debridement ○ removal of whole infected and necrotic bones ■ sequestrectomy ○ Excised Sinus tract ○ Scarring and contamination of soft tissues ○ implant removal is needed if infected or unstable ● Dead space managements ○ Placing antibiotic beads into the bone ○ pack beads loosely ■ maximizes surface area exposures ○ Beads are strung on surgical wires ■ easier removal ● Wound closures ○ primary closure is encouraged ○ may use flap coverage if needed Mechanism of actions ● Beads release high local antibiotic concentrations ○ 100-1000x higher compared to systemic level ● bactericidal concentration in bone tissues ○ IV alone fails ○ poor vascular penetrations ○ Elution kinetics ■ withing first 24-72 hours ○ gradual tapering ■ last up to weeks ■ PMMA porosity ■ bead size Advantages Limitations High local drug level PMMA beads need removal Low systemic toxicity Only ~10% drug released Fills bone dead space Can become bacteria nidus Prevents recolonization No structural support Customizable to cultures Extra cost (esp. resorbables) Helps prep site for graft/fixation May cause sterile drainage (resorbables)