Biomechanical Study on Segmental Compression of Rabbit Spine / 医用生物力学

Objective To investigate the pathological mechanism of spinal injury by axial compression experiment on animal spine, so as to provide references for the treatment, prevention and research of spinal injury. Methods The biomechanical study of rabbit spine segments was performed by axial segment compression experiment. The compression process was recorded and strain analysis was performed by digital image correlation (DIC) technology. Results From the top to the bottom of the spine, the ultimate load and bearing capacity of the segment increased continuously; the average limit load of the corresponding single vertebral body was significantly larger than the segment; the strain of the intervertebral disc in the horizontal and vertical directions was significantly larger than that of the upper and lower vertebral bodies. Conclusions In the process of spine compression, the bearing capacity of the intervertebral disc should be taken into account and the injury of spinal segments is mainly manifested as abnormality of the intervertebral disc. The research findings contribute to the prevention and treatment of spinal compression fractures, as well as the design of related therapeutic instruments and assistive devices.

Analysis of thoracic epidurography and correlating factors affecting the extent of contrast medium spread

BACKGROUND: Thoracic epidural anesthesia is frequently used to maintain intraoperative and postoperative analgesia. Frequently, 3 ml of local anesthetic is used as a test dose, or for intermittent epidural injection. We assessed the extent of the spread of 3 ml of contrast medium in the thoracic epidural space and attempted to identify any correlating factors affecting the epidurography. METHODS: A total of 70 patients were enrolled in the study, and thoracic epidural catheterizations were performed under fluoroscopic guidance. Using 3 ml of contrast medium, epidurography was evaluated to confirm the number of spinal segments covered by the contrast medium. Correlation analysis was performed between patient characteristics (sex, age, body mass index, weight, height, and location of catheter tip) and the extent of the contrast spread. RESULTS: The mean number of vertebral segments evaluated by contrast medium was 7.9 ± 2.2 using 3 ml of contrast medium. The contrast spread in the cranial direction showed more extensive distribution than that in the caudal direction, with statistical significance (P < 0.01). Patient height demonstrated a negative correlation with the extent of distribution of contrast medium (r = −0.311, P < 0.05). CONCLUSIONS: Thoracic epidurography using 3 ml of contrast medium results in coverage of a mean of 7.9 ± 2.2 spinal segments, with more extensive cranial spread, and patient height showed a weak negative correlation with the distribution of contrast medium.

Analysis of thoracic epidurography and correlating factors affecting the extent of contrast medium spread

BACKGROUND: Thoracic epidural anesthesia is frequently used to maintain intraoperative and postoperative analgesia. Frequently, 3 ml of local anesthetic is used as a test dose, or for intermittent epidural injection. We assessed the extent of the spread of 3 ml of contrast medium in the thoracic epidural space and attempted to identify any correlating factors affecting the epidurography. METHODS: A total of 70 patients were enrolled in the study, and thoracic epidural catheterizations were performed under fluoroscopic guidance. Using 3 ml of contrast medium, epidurography was evaluated to confirm the number of spinal segments covered by the contrast medium. Correlation analysis was performed between patient characteristics (sex, age, body mass index, weight, height, and location of catheter tip) and the extent of the contrast spread. RESULTS: The mean number of vertebral segments evaluated by contrast medium was 7.9 ± 2.2 using 3 ml of contrast medium. The contrast spread in the cranial direction showed more extensive distribution than that in the caudal direction, with statistical significance (P < 0.01). Patient height demonstrated a negative correlation with the extent of distribution of contrast medium (r = −0.311, P < 0.05). CONCLUSIONS: Thoracic epidurography using 3 ml of contrast medium results in coverage of a mean of 7.9 ± 2.2 spinal segments, with more extensive cranial spread, and patient height showed a weak negative correlation with the distribution of contrast medium.

Alterations of Glutamate and GABA Immunoreactivities in the Anterior Horn of the Ischemic Spinal Cord of the Rabbit / 대한정형외과학회잡지

PURPOSE: This study was carried out to investigate chronological changes of glutamate and gamma-aminobutyric acid (GABA) immunoreactivities in the anterior horn of the spinal cord after ischemia-reperfusion. MATERIALS AND METHODS: Spinal cord ischemia was induced by clamping the abdominal aorta for 15 minutes in New Zealand white rabbit, and then the spinal cord was reperfused. These animals were sacrificed at 0.5, 1, 3, 6, 12, 24 and 48 hours after ischemia-reperfusion. Spinal cord sections at the level of L7 were immunostained against glutamate and GABA. RESULTS: Glutamate immunoreactive neurons and fibers were first detected in the lamina IX at 30 minutes, but at 1 hour, the immunoreactivity returned to the control level. At 6 hour, glutamate immunoreactivity was observed around the blood vessels and its immunoreactivity increased between 6 and 12 hour. Thereafter the immunoreactivity decreased and eventually disappeared at 48 hours. GABA immunoreactivity increased in the anterior horn from 6 to 12 hours. Thereafter, GABA immunoreactivity decreased and eventually disappeared at 48 hours. CONCLUSION: These results suggest that the alteration of the glutamate immunoreactivity may occur much rapidly than that of GABA immunoreactivity in spinal anterior horn after ischemia-reperfusion.