196. Clinical characteristics of 98 patients presenting with hematogenous spinal osteomyelitis: An observational study

Abstract

<h3>BACKGROUND CONTEXT</h3> Most spinal infection occurs in the wake of invasive procedures, wherein flora have been directly inoculated into the spine and its surrounding soft tissues. Hematogenous infections, on the other hand, result from bacterial spread from a distant site. Staphylococcus aureus is the most common cause of hematogenous spinal infections, and most cases resolve with a 6-week course of antibiotics. However, some patients, especially those that present with concurrent epidural abscess and neurological embarrassment, require debridement of the site and potential structural stabilization. Since very few studies report the clinical characteristics of patients requiring surgery or succumbing to this disease state, this study aims to detail our series of patients with hematogenous spinal osteomyelitis. <h3>PURPOSE</h3> To report clinical characteristics of patients with hematogenous spinal osteomyelitis <h3>STUDY DESIGN/SETTING</h3> Retrospective study. <h3>PATIENT SAMPLE</h3> A total of 98 patients with hematogenous vertebral osteomyelitis. <h3>OUTCOME MEASURES</h3> Preoperative (preop) and postoperative (postop) courses of antibiotics, surgery, reoperation, length of hospital stay, postop sequelae and death. <h3>METHODS</h3> The medical records of patients presenting to two tertiary care centers from January 2014 to January 2021 with hematogenous spinal osteomyelitis were abstracted using ICD-10 codes M46.20 to M46.59. We collected age, sex, body mass index (BMI), comorbidities, affected spinal region, microbiological details, type and duration of pre- and postop antibiotics, length of hospital stay (LOS), reoperation and mortality. Long-term antibiotics were those in use > 6 months. <h3>RESULTS</h3> A total of 98 consecutive patients presenting with hematogenous vertebral osteomyelitis were included. Demographically, the mean age was 62±10 years; 61.2% (n-=60) were male; mean BMI was 29.2±10.4. Most of the infections occurred in the lumbar region (44.2%), followed by the thoracic spine (37.9%), more than two spinal regions (9.5%) and cervical spine (8.4%). Biopsy was performed in 94.1% and returned positive cultures in 93.4%. Of the cultures taken, gram positive bacteria accounted for 69.2%, gram negative in 16.7%, and fungus in 2.6%. 11.5% of cultures returned no growth. 76 (77.6%) patients underwent surgery while 22 (22.4%) were treated with antibiotics only. Of the 76 undergoing surgery, 34.2% underwent secondary surgeries due to a heavy wound burden of necrotic tissue and pus or the failure of multimodal care including antibiotics and debridement. 51.6% of the patients had been prescribed antibiotics preoperatively, with a mean course of 37.2±25.7 days. Postoperative antibiotics were prescribed to all patients, with a mean length of 70.2 days. Mean LOS was 17.9±15.3 days. Additionally, 51.6% of the patients were prescribed long-term antibiotic therapy. The overall death rate was 3.1% (n=3). All 3 patients underwent surgery. Demographic and clinical characteristics of the deceased patients include a mean age of 64 years, majority male (66.7%), who had major comorbidities such as diabetes, anemia, obstructive lung disease and hypertension. Major cause of death was septic shock. Major post-infection sequelae occurred in 24.5% (n=24) of patients. Patients suffering sequelae had a mean age of 69.3 years, were mostly male (83%) and carried major comorbidities including diabetes, anemia, hypertension and renal disease. The most common sequelae were major motor weakness, wound dehiscence and meningitis. <h3>CONCLUSIONS</h3> This study describes the clinical characteristics of patients presenting with hematogenous spinal osteomyelitis, their treatment course and outcomes. As in other sites of infection, the presence of major comorbidities (diabetes, hypertension and renal failure) appear to increase the risk of developing post infection sequalae and death. Our population included patients hospitalized in a tertiary care center with spinal osteomyelitis. They were therefore more likely to carry concomitant diagnoses such as epidural abscess, resulting in a high rate of surgical intervention. A future study with a larger sample size utilizing logistic regression would be able to identify significant risk factors both for hematogenous infection itself and for failure of non-operative and initial operative care. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.