| Purpose:1.Establish a model of intervertebral space infection in New Zealand white rabbits,and inoculate Staphylococcus aureus into the intervertebral disc under the percutaneous puncture of the rabbit disc under the assisted guidance of the C-arm machine.2.Different interventions were used to treat the model of intervertebral space infection in New Zealand white rabbits,and the treatment effects of conservative treatment and minimally invasive surgery were compared.Method:1.A model of intervertebral space infection in New Zealand white rabbits was established:From May to December 2022,9 New Zealand white rabbits were selected from the Animal Experiment Center of China Medical City,and 3 experimental rabbits were randomly vaccinated with 10~3cfu/ml,10~4cfu/ml and 10~5cfu/ml suspension of Staphylococcus aureus for pre-experiments,so as to determine the concentration of bacteria that could successfully establish an infection model.The results of the pre-experimental experiment showed that the successful infection of the rabbit intervertebral space with the bacterial suspension concentration of 10~5cfu/ml did not cause death.The remaining 6 experimental rabbits were inoculated with 10~5 CFU/m L bacterial suspension according to the results of the pre-experiment to establish a model of intervertebral space infection.The experimental animal was placed in a prone position,and a 5 ml syringe needle was used to percutaneously puncture into the L5/6 intervertebral space of the animal under the guidance of a C-arm machine,and the prepared 0.1 ml Staphylococcus aureus suspension was injected into the intervertebral disc.After inoculation with the bacteria,the animals were continuously observed,blood tests were drawn,and lumbar spine MRI was performed 1 week later to assess the infection.2.Comparison of the efficacy of the two treatment modalities:Six infected New Zealand white rabbits were randomly divided into two groups:minimally invasive surgery(3)and conservative treatment(3).The minimally invasive surgery group used a small incision in the posterolateral approach of the right decubitus position to expose the intervertebral disc,and the abscess was completely removed by local drilling,and vancomycin hydrochloride+levofloxacin hydrochloride was given antibiotic therapy after surgery;The conservative treatment group was only treated with vancomycin hydrochloride+levofloxacin hydrochloride intramuscular injection daily,and no special treatment was given to the rest.Before and after treatment,the general performance of animals,blood sampling routine and CRP laboratory and lumbar MRI examination were regularly observed to compare the efficacy of the two groups.Results:1.In the early experiment,10~5 cfu/ml suspension of Staphylococcus aureus was used to successfully induce intervertebral space infection in the target intervertebral disc,and the inoculation concentration of 6 experimental rabbits was finally determined to be 10~5cfu/ml.After inoculation with bacterial solution,the weight of each experimental rabbit decreased significantly,compared with the third day after puncture,there was no significant P>0.05,and on the 5th and 7th days after puncture,compared with before puncture,the weight loss was statistically significant P<0.05,the body temperature gradually decreased and returned to normal after the peak of fever on the 3rd day of infection,the increase in body temperature on the 3rd day after puncture compared with before puncture was statistically significant P<0.05,and the rest of the time points were not statistically significant P>0.05.The white blood cell count rises gradually after inoculation of bacteria;neutrophils are briefly elevated on day 5 of infection;CRP levels reached the highest value on the third day,and the increase in CRP on the third day after puncture compared with pre-puncture P<0.05 was statistically significant,and there was no significant significance at the rest of the time points.Cellular and neutrophil changes were not statistically significant.On the 7th day after infection,lumbar spine MRI was performed,and T2 images showed that the intervertebral discs of the six experimental rabbits inoculated with bacteria had signal changes.Several indicators prove successful infection.2.The results before and after treatment of the two groups were compared:1 patient in the minimally invasive surgery group had postoperative blood in the stool,and 1 had left lower limb claudication after awakening from anesthesia,which was not treated and improved over time,and the experimental rabbits in the remaining minimally invasive surgery group all developed obvious postoperative complications and good incision healing.Weight gain was more significant in the minimally invasive treatment group before and after treatment than in the conservative treatment group,and the weight change between the two groups was statistically significant from day 5 to 2 weeks after treatment,P<0.05.Only 2 in the minimally invasive surgery group developed fever on the second day after surgery,and then their body temperature gradually returned to normal.There was no significant change in body temperature fluctuation in the conservative treatment group,and the temperature change on the second day after treatment in the two groups was statistically significant P<0.05,and the temperature change at the rest of the time points was not statistically significant.Laboratory tests:the white blood cell count of the two groups of rabbits gradually decreased after treatment;CRP gradually increased in the early stages of treatment.The overall trend of neutrophil count was similar,and there were no significant significance before and after white blood cell count,neutrophil count,and CRP treatment in the two groups.MRI of the lumbar spine showed that the adjacent endplate and bone mass were destroyed in the conservative treatment group,but no obvious spinal cord compression,no obvious spinal deformity,and the area of vertebral body signal change increased compared with before.In the minimally invasive treatment group,the surgical segment showed obvious signal increase,and the upper and lower vertebral bodies and surrounding soft tissues of the intervertebral disc were severely edematous,and the intervertebral space signal was not clear.Conclusion:In this study,a model of intervertebral space infection in rabbits was successfully established.Through the treatment of different interventions,it has been preliminarily proved that minimally invasive surgery combined with antibiotic treatment is more effective than conservative treatment. |
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