Factors prolonging antibiotic duration and impact of early surgery in thoracolumbar pyogenic spondylitis treated with minimally invasive posterior fixation

Purpose: A standard 6-12-week course of antibiotics is recommended for pyogenic spondylitis. Recent evidence supports early minimally invasive posterior fixation surgery; however, its effect on antibiotic treatment duration is unclear. This study aims to identify factors associated with prolonged antibiotic treatment in thoracolumbar pyogenic spondylitis patients resistant to conservative treatment and assess whether early surgery can reduce treatment duration.

Methods: We retrospectively reviewed 74 patients with thoracolumbar pyogenic spondylitis undergoing minimally invasive posterior fixation at nine facilities. Patients were grouped based on antibiotic duration (≥ 6 or < 6 weeks) and timing of surgery (≤ 3 weeks or > 3 weeks of starting antibiotics). Univariable and multivariable logistic regression analyses were used to identify factors associated with prolonged antibiotic treatment and study the outcomes of patients undergoing early surgery.

Results: Forty-nine patients (66%) required prolonged antibiotic treatment. The presence of an iliopsoas abscess (p = 0.0006) and elevated C-reactive protein (CRP) levels (≥ 10 mg/dL, p = 0.015) were independently associated with prolonged antibiotic treatment. Early surgery significantly reduced total antibiotic duration (5.3 weeks vs. 9.9 weeks, p < 0.0001) without increasing the incidence of postoperative infection recurrences and unplanned additional surgeries. Despite factors associated with prolonged antibiotic treatment, early surgery consistently shortened the treatment duration compared to late surgery.

Conclusions: Early surgery (within three weeks) with minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis is associated with reduced antibiotic duration and overall treatment duration regardless of the presence of prolonging factors like iliopsoas abscess and elevated CRP levels.