Clinical Test Of Pedicle Screw System For Thoracol-Umbar Fixation In Dogs

In the past ten years,with the development of the economy,the small animal veterinary has developed rapidly.In particular,the popularity of X-ray examination,computer tomography and magnetic resonance imaging has greatly enriched the means of neurological disease examination.It has made it possible to diagnose and treat some cases that were difficult in the past.Neurosurgery is becoming more and more important as the best treatment for many spinal diseases such as spinal fractures and disc herniation.Spinal disease is a relatively common disease which is most common in cervical,thoracolumbar and lumbar sacral abnormalities caused by trauma and dysplasia.Vertebral column realignment/stabilization is a commonly used surgery for spinal dislocation and unstable diseases caused by traumatic vertebral fractures,dislocations or subluxations,and dysplasia.There are many methods of spinal fixation.The most commonly methods are needle and polymethyl methacrylate(PMMA),screws and bone plates(pearl bone plates,locking bone plates).As an excellent spinal fixation system,the pedicle screw system has been reported in human medical neurosurgery.The results show that the pedicle screw greatly facilitates the surgical operation and significantly improves the clinical prognosis of spinal diseases.In human medicine,the anatomical structure of the human pedicle had been studied in detail in people of different races,ages and genders.Many in vitro experiments and clinical observation had been made.Due to the differences spine anatomical structure between canine and human,the small size of canine vertebral column and there are important anatomical structures nearby such as the spinal cord,azygos veins,aorta and caudal vena cava,the allowable operation space is limited.Improper implantation or improper implant size selection can cause serious complications such as spinal cord injury,pneumothorax,blood vessel injury in the chest cavity or abdominal cavity.However,in the veterinary field,there are few researches on pedicle screw systems.The neurosurgery direction requires pedicle screw systems to improve the clinical prognosis.First,studied the local anatomical structure of canine’s thoracic and lumbar spine.Secondly,used computer tomography to study the appropriate implantation pathway of the pedicle screw system in the canine thoracolumbar vertebrae.Thirdly,made external spinal fixation models.After euthanasia,the T12 to L4 spinal column of the dog was immediately taken.The spinal column in control group was untreated.In the test group,the ligaments,joints,and intervertebral discs of the spinal column were destroyed to make the spinal instability model.Then the pedicle screws were used to fix the spine column between T13 and L1.Measuring the canine’s thoracolumbar spine in vitro stability after the pedicle screw system is fixed.Finally,selected three appropriate clinical cases(2 cases of intervertebral disc.prolapse,1 case of spinal chondrosarcoma)to use the pedicle screw system to fix after removal of prolapsed disc material or removal of tumor,continuous tracking,observing its recovery,and evaluating the tolerance level and prognosis of the pedicle screw system in vivo,providing a certain reference for the application of pedicle screw system to the thoracolumbar spine fixation in canines.The result shows that the animals recovered well after the operation,the pain and weakness of the hind limbs disappeared,and no symptoms of spinal instability occurred.The pedicle screw has the advantages of simple operation,firm fixation and good effect,can be popularized in pet clinic.