Journal of neurotrauma
-
Journal of neurotrauma · Nov 2017
Spinal transection alters external urethral sphincter activity during spontaneous voiding in freely-moving rats.
The rat is a commonly used model for the study of lower urinary tract function before and after spinal cord injury. We have previously reported that in unanesthetized freely moving rats, although phasic external urethral sphincter (EUS) activity (bursting) is most common during micturition, productive voiding can occur in the absence of bursting, which differs from results seen in anesthetized or unanesthetized restrained animals. The purpose of the present study was to characterize EUS behavior in unanesthetized, freely moving rats before and after mid-thoracic (T8) or thoraco-lumbar (T13-L1) spinal transection to determine how EUS behavior after spinal cord injury differs from that seen in anesthetized or unanesthetized restrained rats. ⋯ These data suggest that transection-induced delayed initiation of EUS bursting allows co-contraction of the bladder and the EUS that prevents or limits urine evacuation, resulting in a detrusor-sphincter dyssynergia-like phenomenon. In addition, the higher-than-normal frequency at which EUS bursting occurs after transection is associated with shorter silent periods during which urine typically flows, which interferes with voiding by slowing the rate of urine evacuation. That results were comparable after either transection suggests that the central pattern generator responsible for EUS bursting is located caudal to the L1 spinal segment.
-
Journal of neurotrauma · Nov 2017
Diffusion Tensor Imaging Parameter Obtained During Acute Blunt Cervical Spinal Cord Injury in Predicting Long Term Outcome.
There are no reliable neuroimaging biomarkers to predict long-term outcome after spinal cord injury. This prospective longitudinal study evaluates diffusion tensor imaging (DTI) in predicting long-term outcome after cervical spinal cord injury (CSCI). We investigate the admission DTI parameters measured in 30 patients with CSCI, with 16 of them followed up to one year, and 15 volunteers serving as controls. ⋯ Further stepwise regression indicated that including AD (p = 0.0001) and presence of HC (p < 0.0001) in the regression model provided the best model fit for one year ISNCSCI (r2 = 0.93). The AD is a more specific parameter for axonal injury than radial diffusivity; this may indicate that axonal injury in the cord is the main factor affecting patient recovery. Our study demonstrates DTI measurement at the CSCI is a potential neuroimaging biomarker in predicting long-term neurological and functional outcome in blunt CSCI.
-
Journal of neurotrauma · Nov 2017
Clinical TrialContinuous monitoring and visualization of optimum spinal cord perfusion pressure in patients with acute cord injury.
The optimum spinal cord perfusion pressure (SCPP) after traumatic spinal cord injury (TSCI) is unknown. Here, we describe techniques to compute and display the optimum SCPP in real time. We recruited adults within 72 h of severe TSCI (American Spinal Injuries Association [ASIA] grades A-C). ⋯ Mean SCPP deviation from cSCPPopt correlated with worse neurological outcome at 9-12 months: ASIA grade improved in 30% of patients with <5 mm Hg deviation, 10% of patients with 5-15 mm Hg deviation, and no one with >15 mm Hg deviation. We conclude that real-time computation and visualization of cSCPPopt after TSCI are feasible. cSCPPopt appears to enhance glucose utilization at the injury site and varies widely between and within patients. Our data suggest that targeting cSCPPopt after TSCI might improve neurological outcome.
-
Journal of neurotrauma · Nov 2017
The relationship between trans-lesional conduction, motor neuron pool excitability and motor function in dogs with incomplete recovery from severe spinal cord injury.
Spontaneous, acute, complete thoracolumbar spinal cord injury (TL-SCI) in dogs frequently results in permanent deficits modeling chronic paralysis in people. Recovery of walking without recovery of sensation has been interpreted in dogs as reflexive spinal walking. To evaluate this assumption, this study characterized the electrophysiological status of motor and sensory long tracts and local reflex circuitry in dogs with absent recovery of sensation after acute TL-SCI and correlated findings to gait scores. ⋯ H threshold in cases (mean, 3.2mA ±2.5) was lower than controls (mean, 7.9mA ±3.1; pa = 0.011) and was inversely associated with treadmill-based scores, SS, and RI (pa = 0.042, 0.043, respectively). The association between pelvic limb MEPs and gait scores supports the importance of descending influence on regaining walking after severe TL-SCI in dogs rather than just activation of spinal walking. The inverse association between H-reflex threshold and gait scores implies that increases in motor neuron pool excitability might also contribute to motor recovery.
-
Journal of neurotrauma · Nov 2017
Application of the Rat Grimace Scale as a Marker of Supraspinal Pain Sensation after Cervical Spinal Cord Injury.
Experimental models of neuropathic pain (NP) typically rely on withdrawal responses to assess the presence of pain. Reflexive withdrawal responses to a stimulus are used to evaluate evoked pain and, as such, do not include the assessment of spontaneous NP nor evaluation of the affective and emotional consequences of pain in animal models. Additionally, withdrawal responses can be mediated by spinal cord reflexes and may not accurately indicate supraspinal pain sensation. ⋯ Rodents exhibited significantly higher RGS scores at week 5 post-injury as compared to baseline and laminectomy controls before the application of the stimulus, suggesting the presence of spontaneous NP. Additionally, there was a significant increase in RGS scores after the application of the acetone. These data suggest that the RGS can be used to assess spontaneous NP and determine the presence of evoked supraspinal pain sensation after experimental cervical SCI.