Determination of cephazolin, ceftazidime, and ceftriaxone distribution in nucleus pulposus

The intervertebral disc is the largest avascular structure in the adult body and minimal blood flow through capillary beds only supplying the outer regions of the disc, which relies on the passive diffusion as a major factor for nutrition and uptake of molecules, including antibiotics. This study is to detect the serum and nucleus pulposus (NP) levels of cephazolin, ceftazidime, and ceftriaxone and to assess this antibiotic permeability into the intervertebral disc. Forty-five consecutive patients undergoing lumbar interbody fusion surgery were divided into three groups to participate in the study. Approximately 30 min before the procedures, a bolus dose 2 g antibiotic of cephazolin, ceftazidime, and ceftriaxone was administered intravenously. The NP tissue and serum sample levels of antibiotic were assayed by high performance liquid chromatography. Three cases failed in the ceftriaxone group because the NP tissue contaminates the blood. Average time between antibiotic injection and tissue/blood collection was 41 min (range 27-57 min). The antibiotic concentration level of cephazolin, ceftazidime, and ceftriaxone was 144.26 +/- A 29.15, 127.19 +/- A 30.22, and 227.81 +/- A 51.48 mu g/ml in serum and 2.33 +/- A 0.45, 3.74 +/- A 1.91, and 2.23 +/- A 1.86 mu g/g in NP, respectively. The antibiotic penetration in to NP of cephazolin was 1.67 +/- A 0.44, 2.99 +/- A 1.99 of ceftazidime, and 1.08 +/- A 1.44 of ceftriaxone. The antibiotics of cephazolin, ceftazidime, and ceftriaxone had concentration in the NP tissue, which was higher than the stated MIC. Ceftazidime had highest penetration in to NP tissue, and ceftriaxone had the lowest penetration in to NP tissue.