Abstract
Aim
Spinal implant-associated infections (SIAI) require combined surgical and antimicrobial treatment and prolonged hospital stay. We evaluated the clinical, laboratory, microbiological and radiological characteristics and treatment approaches in patients with SIAI.
Method
Consecutive adult patients with SIAI treated between 2015 and 2017 were prosepctively included. SIAI was defined by: (i) significant microbial growth from intraoperative tissue or sonication fluid, (ii) intraoperative purulence, secondary wound dehiscence or implant on view, (iii) radiographic evidence of infection and fever (>38°C) without other recognized cause, increasing back pain or neurologic impairment, (iv) peri-implant tissue inflammation in histopathology.
Results
A total of 60 patients were included, median age was 66 years (range, 28–91 years), 29 (48%) were males. The most common reason for spinal stabilization was spinal canal stenosis in 20 patients (33%) followed by vertebral degenerative disease in 14 (23%). 31 patients (52%) had one or more previous spine surgeries (range, 1–4 interventions). The anatomic site of spinal instrumentation was lumbar/sacral in 26 (43%), cervical in 23 patients (38%), thoracic in 11 (18%). The median number of fused segments was 5 (range, 1–14). Clinical manifestations included wound healing disturbance in 41 patients (68%), increasing back pain in 15 (25%), neurologic impairment in 12 patients (20%) and fever in 14 (23%). Serum CRP was abnormal (>10mg/l) in 46/59 patients (78%). Most (n=54) infections were postsurgical, 5 were hematogenous and 1 was contiguous. Imaging showed epidural, intraspinal or paravertebral abscess in 21/42 patients (50%), implant failure in 9 (21%) and implant loosening in 3 cases (7%). Monomicrobial infection was observed in 41 (68%), polymicrobial in 16 (27%) patients and culture-negative infection in 3 episodes (5%). Predominant causative pathogens were S. aureus (n=19), coagulase-negative staphylococci (n=18) and gram-negative rods (n=16). Surgery was performed in all patients including debridement and implant retention in 39 patients (65%), partial implant exchange in 10 (17%) and complete exchange in 11 (18%). Antimicrobial treatment included biofilm-active substances in 52 patients (87%). The median duration of antimicrobial therapy was 11,7 weeks (range, 6–12 weeks). 14 patients (23%) recieved suppressive therapy for a median duration of 9 months (range 3–12 months).
Conclusions
Most SIAI were seen in lumbar/sacral segments and wound healing disturbance and increasing back pain were the most common manifestations. In 95% the causative pathogen was isolated, predominantly staphylococci. In half of the episodes, abscesses were present. All patients underwent surgery and biofilm-active antibiotics were administered in 87%.
