Antibiotic-impregnated bone graft decreases time to CRP normalization in pyogenic discitis with vertebral osteomyelitis

Abstract Introduction Surgical treatment of pyogenic discitis with vertebral osteomyelitis (PDVO) is indicated for neurologic deficit, spinal instability, unknown pathogen, poorly controlled infection, or intractable pain. Although the posterior-only approach has been proved a safe, effective procedure that minimizes the risks and complications of anterior or staged surgery, parenteral antibiotic treatment for 4-6 weeks postoperatively is still necessary. We hypothesized that antibiotic-impregnated bone graft used in an all posterior approach could result in infection control and shorten the postoperative course of pyogenic discitis and vertebral osteomyelitis. Patients and Methods 21 consecutive patients with pyogenic discitis and vertebral osteomyelitis of the lumbar or thoracic spine were treated with transforaminal interbody debridement and fusion (TIDF) with antibiotic-impregnated bone graft (AIBG) between March 2014 and January 2017. Minimum follow up was 2 years. Outcomes included visual analog scale (VAS) back pain, ASIA scale for neurological status, kyphotic angle correction, fusion status, and functional outcome using Kirkaldy-Willis criteria, and c-reactive protein (CRP) levels. CRP levels from pre-op, immediately post-op, and 1, 2, 4 & 6 wks post operatively and the duration of treatment with postoperative IV antibiotics in our patients was compared to our previous case series in which TIDF was performed without AIBG. Results Surgical treatment for PDVO resulted in clinical improvement and adequate infection control. There was no difference in pre-op CRP levels between the two groups. Despite shorter post-op IV antibiotic duration (Mean 21.0 d vs 39.8 d), the AIBG group had a stable decline in CRP levels and continued to decrease at 1, 2, 4 & 6 wks, with significantly lower CRP levels at 6 weeks compared to bone graft without antibiotics. VAS scores improved from a mean of 7.2 to 2.3 one month postoperatively. Patients who had increased kyphotic angles had an average angle correction of 7.9° at last follow-up. Eighty-one percent of patients (17/21) had good to excellent functional outcomes. Conclusion TIDF combined with AIBG can achieve local infection control with faster reduction in CRP, leading to shorter antibiotic duration for pyogenic discitis and vertebral osteomyelitis