Subtherapeutic levels of cefuroxime inside a cannulated pedicle screw used in spine surgery: results from a porcine microdialysis study

Abstract

Background and purpose: Minimally invasive spine surgery has continuously evolved for specific surgical procedures and patient populations to lower morbidity and the risk of postoperative bacterial infection. Perioperative antibiotic prophylaxis is an important preventive measure and local tissue concentrations can be quantified with microdialysis. Insertion of spinal implants induces tissue trauma and inflammation, which may affect antibiotic proximate implant concentrations. We compared perioperative cefuroxime concentrations inside a cannulated pedicle screw used in minimally invasive spine surgery with the opposite non-instrumented vertebral pedicle.Materials and methods: Microdialysis catheters were placed inside a cannulated pedicle screw and in the opposite non-instrumented vertebral pedicle of the same vertebra (L1) in 8 female pigs through a posterior lumbar surgical approach. Following a single-dose intravenous cefuroxime administration (1.5 g), dialysates and plasma were dynamically sampled over 8 hours. The primary endpoint was time above the cefuroxime clinical breakpoint minimal inhibitory concentration for Staphylococcus aureus of 4 μg/mL (T>MIC4).Results: Median T>MIC4 was 0 h (range 0–0) inside the cannulated pedicle screw, 1.6 h (range 1.1–2.4) in non-instrumented vertebral pedicle, and 1.9 h (range 1.9–2.9) in plasma.Conclusion: A single-dose intravenous cefuroxime administration provided low and subtherapeutic concentrations for prevention of infection inside a cannulated pedicle screw in the lumbar spine. Therapeutic concentrations were achieved in the opposite non-instrumented vertebral pedicle up to 1.5–2 h. Therefore, additional prophylactic strategies may be considered in cannulated instrumented spine surgery, especially in high-risk patients. Alternative dosing regimens seem relevant in lumbar spine surgery lasting longer than 1.5 h.

Evaluation of cefuroxime concentration in the intrathecal and extrathecal compartments of the lumbar spine—an experimental study in pigs

“…The study was reported in compliance with the ARRIVE guidelines (Percie du Sert et al, 2020) and with the recommendations made by the British Journal of Pharmacology (Lilley et al, 2020). With reference to reduction, refinement and replacement (the 3Rs) (Tannenbaum & Bennett, 2015), the pigs used in this study were also included in studies assessing cefuroxime concentrations in the anterior and posterior vertebral column of the spine and inside a cannulated pedicle screw (Hvistendahl, Bue, et al, 2022; Hvistendahl, Hanberg, et al, 2022).…”