Post Lumbar Fixation Spondylodiscitis: Prevalence and Microbiological Profile

Background: Spondylodiscitis refers to spinal infections, including vertebral osteomyelitis, spondylitis, and discitis. Its incidence is rising due to invasive spinal interventions among other reasons. Postoperative spondylodiscitis (POSD) often results from poor aseptic techniques or hematogenous dissemination, with incidence rates varying widely. Culture negativity in spondylodiscitis complicates diagnosis and treatment plans. This study evaluates culture-positive versus culture-negative cases and reflects on the prevalence of POSD among patients underwent spinal surgery. Methods: This retrospective cohort study, conducted at Beni Suef University Hospital (2022-2024), included 20 postoperative spondylodiscitis (POSD) patients divided into culture-positive and culture-negative groups. Data extracted included demographics, clinical symptoms, surgical details, and microbiological, laboratory, and radiological findings. Outcomes such as recovery, hospital stay, and treatment were analyzed. Statistical methods included chi-square, Fisher’s exact test, t-tests, logistic regression, and survival analysis to compare groups and identify factors associated with culture positivity. Ethical approval was obtained, and patient confidentiality was ensured through anonymized data. The primary goal was to assess the prevalence of POSD among spine surgical patients and draw comparisons between culture-positive and culture-negative cases. Results: This study analyzed 20 cases of POSD among 288 lumbar fixation surgeries (6.94% prevalence). The average patient age was 45.4 years, with a male to female ratio of 1:1.5. Nearly half had diabetes, and 80% had multiple spinal levels affected. Symptoms typically began 16 days post-surgery and included wound discharge (70%) and back pain (45%). Elevated CRP and ESR levels were observed. Half of the cultures showed no growth; others revealed pathogens like S. aureus (15%) and MRSA (15%). BMI was the sole significant factor associated with culture positivity, doubling the odds of culture-positive POSD (OR = 2.003). Culture-positive cases required earlier second surgeries than culture-negative ones, highlighting the role of obesity and microbial culture results in treatment outcomes. Conclusion: Our study revealed a 6.94% prevalence of POSD in lumbar fixation surgery patients, with BMI as the only identified predictor for culture-positive cases. Culture-negative POSD showed better surgical outcomes, highlighting diagnostic challenges and the need for methods to improve microbiological detection and evidence-based management strategies.