Implant Microbial Colonization Detected by Sonication as a Cause for Spinal Device Failure: A Prospective Study

Area of Science:

• Spinal surgery
• Infectious diseases
• Diagnostic microbiology

Background:

• Spinal implant loosening is often attributed to mechanical factors, but implant colonization and biofilm formation are increasingly recognized.
• Diagnosing low-grade spinal implant infections is challenging due to nonspecific clinical presentations.
• Sonication fluid culture shows promise for detecting spinal instrumentation infections, yet data remain limited.

Purpose of the Study:

• To evaluate sonication's role in diagnosing low-grade spinal implant infections.
• To investigate the association between sonication results and pedicle screw (PS) loosening.
• To identify risk factors and radiological findings linked to spinal implant infection.

Main Methods:

• Prospective observational study including patients undergoing implant removal.
• Assessment of pedicle screw (PS) loosening using computed tomography (CT) scans.
• Analysis of clinical and radiological parameters as indicators of implant infection.

Main Results:

• A positive sonication result was observed in 29% of patients (11 out of 38).
• Spinal implant infection correlated significantly with screw loosening (P = 0.005).
• Independent risk factors for infection included screw loosening, absence of prophylactic cefazolin, ICU hospitalization, screw breakage, and L1-L3 spine level.

Conclusions:

• Sonication fluid analysis can aid in diagnosing spinal implant infections.
• Preoperative prediction and risk stratification of implant colonization are possible by considering identified factors.
• This approach assists in managing patients with potential implant-associated infections.