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Occult infection in pseudarthrosis revision after spinal fusion
Marco D Burkhard1, Ruben Loretz1, Ilker Uçkay2
1Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Switzerland.
Background Context:
Pseudarthrosis after attempted spinal fusion is yet not sufficiently understood and presents a surgical challenge. Occult infections are sometimes observed in patients with pseudarthrosis and no inflammatory signs of infection. The prevalence of such occult infection and its association with patient demographics and inflammatory markers are largely unknown.
Purpose:
To determine the prevalence of unexpected low-grade infection in spinal pseudarthrosis revision surgery, and to evaluate whether such infection is associated with patient demographics and inflammatory markers.
Study Design:
Retrospective observational study.
Patient Sample:
One-hundred-and-twenty-eight patients who underwent thoracolumbar revision surgery due to presumed aseptic pseudarthrosis after spinal instrumentation.
Outcome Measures:
Culture-positive infections or noninfectious pseudarthrosis.
Methods:
Samples were routinely taken for microbiological examination from all adults (n=152) who underwent revision surgery for presumed aseptic thoracolumbar pseudarthrosis between 2014 and 2019. A full intraoperative microbiological workup (at least three intraoperative tissue samples) was done for 128 (84%) patients, and these patients were included in further analyses. Patient characteristics, medical history, inflammatory markers, and perioperative data were compared between those with and without microbiologically-confirmed infection based on samples obtained during pseudarthrosis revision.
Results:
The microbiological workup confirmed infection in 13 of 128 cases (10.2%). The predominant pathogen was Cutibacterium acnes (46.2%), followed by coagulase-negative staphylococci (38.5%). The presence of infection was associated with the body mass index (30.9±4.7 kg/m2 [infected] vs. 28.2±5.6 kg/m2 [controls], p=.049), surgery in the thoracolumbar region (46% vs. 18%, p=.019), and a slightly higher serum C-reactive protein level on admission (9.4±8.0 mg/L vs. 5.7±7.1 mg/L, p=.031). Occult infection was not associated with age, sex, prior lumbar surgeries, number of fused lumbar levels, American Society of Anesthesiologist score, Charlson Comorbidity Index, presence of diabetes mellitus, and smoking status.
Conclusions:
Occult infections were found in 10% of patients undergoing pseudarthrosis revision after spinal fusion, even without preoperative clinical suspicion. Occult infection was associated with higher body mass index, fusions including the thoracolumbar junction, and slightly higher C-reactive protein levels. Intraoperative microbiological samples should be routinely obtained to exclude or identify occult infection in all revision surgeries for symptomatic pseudarthrosis of the spine, as this information can be used to guide postoperative antibiotic treatment.
Insights
Occult infections are present in 10% of spinal pseudarthrosis revision surgeries. Higher body mass index and thoracolumbar fusion were associated with infection, necessitating routine intraoperative cultures for accurate diagnosis and treatment.
Area of Science:
- Spine surgery
- Infectious disease
- Orthopedics
Background:
- Pseudarthrosis after spinal fusion presents a surgical challenge, with occult infections sometimes present without clear inflammatory signs.
- The prevalence and patient-associated factors of occult infections in spinal pseudarthrosis remain largely unknown.
Purpose of the Study:
- To determine the prevalence of unexpected low-grade infections in spinal pseudarthrosis revision surgery.
- To evaluate associations between such infections and patient demographics or inflammatory markers.
Main Methods:
- Retrospective observational study of 128 patients undergoing thoracolumbar revision surgery for presumed aseptic pseudarthrosis.
- Intraoperative tissue samples were collected for microbiological examination.
- Patient characteristics, medical history, and inflammatory markers were compared between infected and non-infected groups.
Main Results:
- Infection was confirmed in 10.2% of cases, with Cutibacterium acnes and coagulase-negative staphylococci as predominant pathogens.
- Infection was associated with higher body mass index (p=.049), thoracolumbar region surgery (p=.019), and elevated C-reactive protein levels (p=.031).
- No significant association was found with age, sex, prior surgeries, or other comorbidities.
Conclusions:
- Occult infections are present in approximately 10% of spinal pseudarthrosis revision surgeries, often without preoperative suspicion.
- Higher body mass index, thoracolumbar fusion, and elevated CRP are associated with occult infection.
- Routine intraoperative microbiological sampling is recommended for all revision surgeries for symptomatic pseudarthrosis to guide treatment.
