EXPERIMENTAL RADIOLOGICAL EVALUATION OF THE SPINAL MOTION SEGMENT STRUCTURAL ELEMENTS AFTER VARIOUS METHODS OF POSTERIOR SPINAL FIXATION

Abstract

The study goal was to experimentally evaluate the condition of the structural elements of the spinal motion segments after different rear fixing methods. The study object were mongrel dogs with weigh of 12±1,5 kg at the age of 21±3 months. Experimental animals were divided into 2 groups. Animals in group 1 (n=5) underwent transpedicular fixation of the spine using rigid rods. Animals of group 2 (n=5) underwent transpedicular fixation of the spine with dynamic rod made of nitinol. All animals were studied by x-ray in functional positions and multispiral computed tomography (MSCT). Range of motion in the tested segment prior to surgery for functional study in both groups was 18±1,2 degree. In group 1 after 24 months range of motion after surgery was 0±0,03 degrees. In group 2 all animals had range of movement 15±1,3°, which was 78,9% of the original. MSCT study showed no degenerative changes of the articular surfaces in group 2 in 24 months after surgery and the movement range still was 78,9% of the original.