SHORT-SEGMENT PEDICLE SCREW FIXATION INCLUDING PEDICLE SCREW AT THE FRACTURED LEVEL FOR TREATMENT OF UNSTABLE THORACOLUMBAR FRACTURES - STABİL OLMAYAN TORAKOLOMBER VERTEBRA KIRIKLARINDA KIRIK SEVİYEYE PEDİKÜLER VİDA FIKSASYONU İLE KISA SEGMENT FIKSASYON SONUÇ