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Adrian K. Dixon, David J. Bowden, Harold Ellis, Bari M. Logan in Human Sectional Anatomy, 2015
This section lies at the level of the intervertebral disc between the seventh and eighth thoracic vertebrae (17) and passes through the body of the sternum (2) at the level of the fourth costal cartilage (3). All four cardiac chambers can be seen and their relationships to each other appreciated. Note that the right atrium (36) forms the right border of the heart. The left atrium (28) is the major contribution to the base of the heart and lies immediately anterior to the oesophagus (22), separated by the pericardium. The left ventricle (32) forms the bulk of the left border of the heart, and the right ventricle (38) constitutes the major component of the anterior cardiac surface.
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Adrian K. Dixon, David J. Bowden, Harold Ellis, Bari M. Logan in Human Sectional Anatomy, 2015
The kidneys (15, 33) are embedded in a mass of fatty connective tissue termed the perirenal (perinephric) fat, which is thickest at their medial and lateral borders. The fibro-areolar tissue surrounding the kidney and perirenal fat condenses to form a sheath termed the renal fascia (35). At the lateral border of the kidney, the two layers of the renal fascia are fused. The anterior layer is carried medially anterior to the kidney and its vessels and merges with the connective tissue anterior to the aorta and inferior vena cava. The posterior layer extends medially in front of the fascia covering quadratus lumborum (14) and psoas major (17) and to the vertebrae and intervertebral discs. The perirenal fat and renal fascia (35) are surrounded by further retroperitoneal (pararenal) fatty connective tissue. The amount varies with the relative obesity of the subject.
Intervertebral Disc
Manoj Ramachandran, Tom Nunn in Basic Orthopaedic Sciences, 2018
This chapter outlines the structure and function of the intervertebral disc, its biomechanical function and relevance in clinical practice. The developed intervertebral disc consists of a tough outer layer (annulus fibrosus) and a soft inner core (nucleus pulposus). The nucleus pulposus represents the inner layer encased by the annulus fibrosus. The vertebral end plate consists of hyaline cartilage in children and is highly vascularized. Herniation of the nucleus pulposus through a defect in the annulus fibrosus most often occurs at the insertion of the outer annulus into the vertebral body, where the stresses and motion are greatest. Disc degeneration occurs due to pathological and non-pathological processes in the disc. Recent advances in the understanding of intervertebral disc biology have led to increasing interests in the development of biological treatments aimed at disc regeneration. Growth factors, gene therapy, stem cell transplantation and biomaterials-based tissue engineering may allow for intervertebral disc regeneration by overcoming the limitations of the self-renewal mechanisms.
Gene therapy for disc degeneration
Published in Expert Opinion on Biological Therapy, 2007
Gianluca Vadalà, Gwendolyn A Sowa, James D Kang
Recent advances in our understanding of the biology of the intervertebral disc have led to increased interest in the development of novel treatments of intervertebral disc degeneration. With the ability to provide sustained delivery of a potentially therapeutic agent, gene therapy has shown much promise in regard to the treatment of disc degeneration. Many new targets for gene therapy have been identified and new vectors are being investigated for use in intervertebral disc applications. Multiple studies have demonstrated the feasibility of intradiscal gene therapy, and recent studies have shown proof of efficacy of vector-mediated gene transfer in the reproducible animal model, as well as the potential to control transgene expression, improving safety. With continued efforts, gene therapy may prove to be an extremely powerful tool in the future treatment of intervertebral disc degeneration.
Vancomycin concentrations in the cervical spine after intravenous administration: results from an experimental pig study
Published in Acta Orthopaedica, 2018
Mats Bue, Pelle Hanberg, Mikkel Tøttrup, Maja B Thomassen, Hanne Birke-Sørensen, Theis M Thillemann, Torben L Andersson, Kjeld Søballe
Background and purpose — Vancomycin may be an important drug for intravenous perioperative antimicrobial prophylaxis in spine surgery. We assessed single-dose vancomycin intervertebral disc, vertebral cancellous bone, and subcutaneous adipose tissue concentrations using microdialysis in a pig model. Material and methods — 8 female pigs received 1,000 mg of vancomycin intravenously as a single dose over 100 minutes. Microdialysis probes were placed in the C3–C4 intervertebral disc, C3 vertebral cancellous bone, and subcutaneous adipose tissue, and vancomycin concentrations were obtained over 8 hours. Venous blood samples were obtained as reference. Results — Ranging from 0.24 to 0.60, vancomycin tissue penetration, expressed as the ratio of tissue to plasma area under the concentration-time curve from 0 to the last measured value, was incomplete for all compartments. The lowest penetration was found in the intervertebral disc. The time to a mean clinically relevant minimal inhibitory concentration (MIC) of 4 µg/mL was 3, 17, 25, and 156 min for plasma, subcutaneous adipose tissue, vertebral cancellous bone, and the intervertebral disc, respectively. In contrast to the other compartments, a mean MIC of 8 µg/mL was not reached in the intervertebral disc. An approximately 3-times longer elimination rate was observed in the intervertebral disc in comparison with all the other compartments (p < 0.001), and the time to peak drug concentration was higher for all tissues compared with plasma Interpretation — Preoperative administration of 1,000 mg of vancomycin may provide adequate vancomycin tissue concentrations with a considerable delay, though tissue penetration was incomplete. However, in order also to achieve adequate intervertebral disc concentrations in all individuals and accommodating a potentially higher MIC target, supplemental application of vancomycin may be necessary.
Evaluation of a rabbit model of adjacent intervertebral disc degeneration after fixation and fusion and maintenance in an upright feeding cage
Published in Neurological Research, 2021
Long Hei, Zhaohui Ge, Wenqi Yuan, Ling Suo, Zhigang Suo, Leilei Lin, Huiqiang Ding, Yusheng Qiu
ABSTRACT Purpose: To establish an animal model of adjacent intervertebral disc degeneration by performing spinal fixation and fusion after percutaneous needle puncture and removal of the intervertebral disc or percutaneous needling of the vertebral body without removal of the intervertebral disc. Methods: We established a model of adjacent intervertebral disc degeneration after spinal fixation and fusion of rabbits maintained in upright feeding cages. Twenty-five healthy New Zealand rabbits were used. In the experimental group, the L3-4 intervertebral disc was percutaneously punctured with an 18-G needle under fluoroscopic guidance. Once degeneration occurred, the L3-4 disc was excised, and interbody fusion was performed. The changes in the adjacent intervertebral discs were observed periodically via X-ray and MRI. In the control group, the L3 vertebral body was percutaneously needled with an 18-G needle under fluoroscopic guidance. The changes in the adjacent intervertebral discs were observed on X-ray and MRI at 4, 8, and 12 weeks after puncture in both groups. At 12 weeks postoperatively, the animals were euthanized, and the histopathologic changes of the adjacent intervertebral discs were assessed using hematoxylin-eosin and TdT-mediated dUTP nick end labeling (TUNEL) staining. The mRNA and protein expressions of aggrecanase-1 were measured by real-time quantitative PCR and Western blot analysis. The product of aggrecan degradation, Aggrecan ARGxx, was measured by Western blot analysis. Results: The degeneration of the intervertebral discs in the adjacent segments in the experimental group increased over time. The mRNA and protein expressions of aggrecanase-1 and the expression of Aggrecan ARGxx in the experimental group were significantly increased after puncture, fixation, and fusion (P