Spinal implant-associated infections: a prospective multicentre cohort study

Area of Science:

• Orthopedics
• Infectious Diseases
• Surgical Infections

Background:

• Spinal implant-associated infections (SIAIs) pose significant challenges.
• Differentiating early-onset and late-onset SIAIs is crucial for management.
• Standardized treatment algorithms are essential for optimal patient outcomes.

Purpose of the Study:

• To evaluate clinical, laboratory, microbiological, radiological, and treatment characteristics of early-onset versus late-onset spinal implant-associated infections.
• To compare diagnostic methods, particularly sonication fluid versus peri-implant tissue samples.
• To analyze surgical approaches and antibiotic strategies based on infection timing.

Main Methods:

• Prospective study of 250 patients with spinal implant-associated infections (2015-2019).
• Classification of infections into early-onset (≤6 weeks) and late-onset (>6 weeks).
• Evaluation of clinical signs, microbiological findings (including sonication fluid analysis), surgical interventions, and antibiotic treatments.

Main Results:

• Early-onset infections (61%) typically presented with local inflammatory signs, while late-onset infections (39%) showed persistent pain.
• Sonication fluid demonstrated higher positivity rates (90%) than peri-implant tissue (79%), especially in late-onset cases (92%).
• Coagulase-negative staphylococci, Staphylococcus aureus, and Cutibacterium spp. were predominant pathogens. Debridement and implant retention was common for early-onset infections, while implant exchange was preferred for late-onset infections.

Conclusions:

• Spinal implant-associated infections are often acquired intraoperatively and manifest early.
• Clinical presentation differs significantly between early-onset (inflammatory signs) and late-onset (pain) infections.
• Sonication is a highly sensitive diagnostic tool, and treatment strategies should be tailored to infection timing and implant status.