Journal of neurotrauma
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In the clinical setting, skin temperature is both easily evaluated and useful in assessments of sympathetic dysfunction. The present study purposed to observe the serial skin temperature changes of both hindlimbs following several types of sciatic nerve injury (complete transection and ligation model [CTL], crush injury model [CRI], and chronic constriction injury model [CCI]) in Sprague-Dawley rats and, further, to delineate the possible mechanisms through various evaluation methods. The temperature differences between the intact and injured areas (ΔT) on the plantar surface and toes varied among the CTL, CRI, and CCI injury models during the acute stage (7 days post-injury). ⋯ The latency and amplitude of the compound muscle action potential (CMAP) in the involved plantar muscle was not found in the CTL group 4 weeks post-injury, but showed gradual restoration in the CRI and CCI models. Regression analysis revealed that the ΔT in the plantar area and toes were affected only by the CMAP amplitude in the involved plantar muscle; therefore, it can be said that the skin temperature on the injured area after sciatic nerve injury was influenced by the functional status of the involved muscle. Measurement of skin temperature can differentiate mild peripheral nerve injury from moderate-to-severe injuries, although its clinical significance might be limited.
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Journal of neurotrauma · Dec 2012
Degeneration of phrenic motor neurons induces long-term diaphragm deficits following mid-cervical spinal contusion in mice.
A primary cause of morbidity and mortality following cervical spinal cord injury (SCI) is respiratory compromise, regardless of the level of trauma. In particular, SCI at mid-cervical regions targets degeneration of both descending bulbospinal respiratory axons and cell bodies of phrenic motor neurons, resulting in deficits in the function of the diaphragm, the primary muscle of inspiration. Contusion-type trauma to the cervical spinal cord is one of the most common forms of human SCI; however, few studies have evaluated mid-cervical contusion in animal models or characterized consequent histopathological and functional effects of degeneration of phrenic motor neuron-diaphragm circuitry. ⋯ We report that phrenic motor neuron loss in cervical spinal cord, phrenic nerve axonal degeneration, and denervation at diaphragm neuromuscular junctions (NMJ) resulted in compromised ipsilateral diaphragm function, as demonstrated by persistent reduction in diaphragm compound muscle action potential amplitudes following phrenic nerve stimulation and abnormalities in spontaneous diaphragm electromyography (EMG) recordings. This injury paradigm is reproducible, does not require ventilatory assistance, and provides proof-of-principle that generation of unilateral cervical contusion is a feasible strategy for modeling diaphragmatic/respiratory deficits in mice. This study and its accompanying analyses pave the way for using transgenic mouse technology to explore the function of specific genes in the pathophysiology of phrenic motor neuron degeneration and respiratory dysfunction following cervical SCI.
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Journal of neurotrauma · Dec 2012
Influence of breaching the connective sheaths of the donor nerve on its myelinated sensory axons and on their sprouting into the end-to-side coapted nerve in the rat.
The influence of breaching the connective sheaths of the donor sural nerve on axonal sprouting into the end-to-side coapted peroneal nerve was examined in the rat. In parallel, the effect of these procedures on the donor nerve was assessed. The sheaths of the donor nerve at the coaptation site were either left completely intact (group A) or they were breached by epineurial sutures (group B), an epineurial window (group C), or a perineurial window (group D). ⋯ The average CAP area and the total number of myelinated axons in the donor nerves were not different among the experimental groups. In conclusion, myelinated sensory axons are able to penetrate the epiperineurium of donor nerves after end-to-side nerve coaption; however, their ingrowth into recipient nerves is significantly enhanced by breaching the epiperineurial sheets at the coaptation site. Breaching does not cause permanent injury to the donor nerve.
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Journal of neurotrauma · Dec 2012
Do traumatic brain contusions increase in size after decompressive craniectomy?
Hemorrhagic contusions (HC) represent a common consequence of traumatic brain injury (TBI) and usually evolve during the first 12 h after trauma. The relationship between decompressive craniectomy (DC) and evolution of the post-traumatic HC is still unclear. The aim of the present study was to evaluate the impact of DC on HC evolution. ⋯ A significant increase (≥2 cc) of any HC during the observation period was detected in 8 patients (14%): 4/25 patients (16%) of Group 1 and 4/32 patients (12.5%) of Group 2 (Fisher exact test two-sided p=0.72). Univariate and multivariate analyses showed that none of the analyzed factors was associated with increased or de novo appearance of any HC. DC does not seem to constitute a risk factor for the evolution of HC.
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Journal of neurotrauma · Dec 2012
Motor vehicle crash-related subdural hematoma from real-world head impact data.
Abstract Approximately 1,700,000 people sustain a traumatic brain injury (TBI) each year and motor vehicle crashes (MVCs) are a leading cause of hospitalization from TBI. Acute subdural hematoma (SDH) is a common intracranial injury that occurs in MVCs associated with high mortality and morbidity rates. In this study, SDH volume and midline shift have been analyzed in order to better understand occupant injury by correlating them to crash and occupant parameters. ⋯ Age and fracture type were found to be significant contributors to SDH volume. This study is a volumetric analysis of real world brain injuries and known MVC impacts. The results of this study demonstrate a relationship among SDH volume, crash mechanics, and occupant characteristics that provide a better understanding of the injury mechanisms of MVC-associated TBI.