Cefuroxime concentrations in the anterior and posterior column of the lumbar spine - an experimental porcine study

BACKGROUND CONTEXT: Surgical site infection following spine surgery is associated with increased morbidity and mortality. Perioperative antibiotic prophylaxis is a key factor in lowering the risk of acquiring an infection. Previous studies have assessed perioperative cefuroxime concentrations in the anterior column of the cervical spine with an anterior surgical approach. However, the majority of surgeries are performed in the posterior column and many surgeries involve the lumbar spine. PURPOSE: The objective of this study was to compare the perioperative tissue concentrations of cefuroxime in the anterior and posterior column during lumbar spine surgery with a posterior surgical approach. STUDY DESIGN: In vivo experimental pharmacokinetic study of cefuroxime concentrations in an acute preclinical porcine model. METHODS: The lumbar vertebral column was exposed from L1 to L5 in 8 female pigs. Microdialysis catheters were placed for sampling in the anterior column (vertebral body) and posterior column (posterior arch) within the same vertebra (L5). Cefuroxime (1.5 g) was administered intravenously. Microdialysates and plasma samples were continuously obtained over 8 hours. Cefuroxime concentrations were quantified by Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry. The primary endpoint was the time above the cefuroxime clinical breakpoint minimal inhibitory concentration (T>MIC) for Staphylococcus aureus of 4 mu g/mL. The secondary endpoint was tissue penetration (AUC(tissue)/AUC(plasma)). RESULTS: Mean T> MIC 4 mu g/mL (95 was 123 min (105- 141) in plasma, 97 min (79- 115) in the anterior column and 93 min (75- 111) in the posterior column. Tissue penetration (95 was incomplete for both the anterior column 0.48 (0.40-0.56) and posterior column 0.40 (0.33- 0.48). CONCLUSIONS: T> MIC was comparable between the anterior and posterior column. Mean cefuroxime concentrations decreased below the clinical breakpoint minimal inhibitory concentration for S. aureus of 4 mu g/mL after 123 ...