Effect of stress on the rehabilitation performance of rats with repetitive mild fluid percussion-induced traumatic brain injuries.

Animal models of traumatic brain injury (TBI) have shown that impaired motor and cognitive function can be improved by physical exercise. However, not each animal with TBI can be well rehabilitated at the same training intensity due to a high inter-subject variability. Hence, this paper presents a two-stage wheel-based mixed-mode rehabilitation mechanism by which the effect of stress on the rehabilitation performance was investigated. The mixed-mode rehabilitation mechanism consists of a two-week adaptive and a one-week voluntary rehabilitation program as Stages 1 and 2, respectively. In Stage 1, the common over and undertraining problem were completely resolved due to the adaptive design, and rats ran voluntarily over a 30-min duration in Stage 2. The training intensity adapted to the physical condition of all the TBI rats at all times in Stage 1, and then the self-motivated running rats were further rehabilitated under the lowest level of stress in Stage 2. For comparison purposes, another group of rats took a 3-week adaptive rehabilitation program. During the 3-week program, the rehabilitation performance of the rats were assessed using modified neurologic severity score (mNSS) and an 8-arm radial maze. Surprisingly, the group taking the mixed mode program turned out to outperform its counterpart in terms of mNSS. The mixed-mode rehabilitation mechanism was validated as an effective and efficient way to help rats restore motor, neurological and cognitive function after TBI. It was validated that the rehabilitation performance can be optimized under the lowest level of stress.

Relationship between Neural Canal Impingement and Neurologic Status after Thoracolumber Burst Fractures / 대한정형외과학회잡지

In the assessment of thoracolumbar fractures, computed tomography (CT) is superior to other imaging modalities especially when a more definitive assessment of the posterior elements of the spine or the neural canal is desired. We evaluated 55 patients with acute thoracolumbar burst fractures, and correlated the amount of neural canal impingement (NCI), demonstrated on computed tomographic scans, with each patients neurologic status, level of injury and extent of recovery when neural deficit was present. The results were as follows ; l. Average NCI was significantly higher in cases with neurologic deficits (57.3%) than in cases with no deficit (29.8%). But the range of NCI was much overlapped between the two groups (32-100% with deficits vs. 8-69% with no deficit). 2. In cases with neurologic deficits, average NCI was significantly higher in lumbar spine (75.0%, range; 61-100%) than in thoracolumbar spine (49.2%, range; 32-87%). 3. There was no neurologic deficit in cases with NCI less than 30% in thoracolumbar spine and less than 60% in lumbar spine. 4. In thoracolumbar spine, there was more significant relationship between NCI and patient's neurologic status in T12 than in Ll. 5. The NCI did not directly correlate with the extent of recovery of neurologic deficits when present.