Stimulation of the spinal cord in the treatment of traumatic injuries of cervical spine

Since 1974, clinical experiments have been conducted at the Rehabilitation Clinic in Konstancin (Poland) on the effects of electrostimulation on the damaged spinal cord. 30 patients with stimulation after injury to the cervical spinal cord are reported. Patients with complete and incomplete cervical cord injury were compared. The patients were treated by surgical decompression with simultaneous implantation of stimulating electrodes in contact with the spinal cord. The control group of patients were operated upon in the same period for similar injuries, but had no stimulators implanted. Neurological improvement was better in the stimulated compared to the nonstimulated patients, both as regards number of neurological improvements as well as quality of neurological function. The comparison also confirmed a favorable effect of spinal cord stimulation on the development of bladder automatism.     

Missed injuries of the spinal cord.

Damage to the spinal cord had not been recognised initially in 15 patients out of a consecutive series of 353 admitted over a decade to the National Spinal Injuries Centre with paralysis due to trauma to the cord. In some patients the missed diagnosis led to mismanagement and a greater neurological deficit. Missed injuries of the spinal cord are seen in patients with multiple injuries and head injuries and in those without any paralysis. Various radiological errors contribute to the failure to recognise the vertebral injury. In addition to causing severe disability to the victim these missed and mismanaged injuries of the spinal cord cost the National Health Service large sums in compensation. A careful evaluation of the history of each accident, with greater awareness of the potential of certain types of accidents to cause spinal cord injury, should reduce the incidence of missed injuries of the spinal cord.     

Regeneration-based therapies for spinal cord injuries

Although it has been long believed that the damaged central nervous system does not regenerate upon injury, there is an emerging hope for regeneration-based therapy of the damaged central nervous system (CNS) due to the progress of developmental biology and regenerative medicine including stem cell biology. In this review, we have summarized recent studies aimed at the development of regeneration-based therapeutic approaches for spinal cord injuries, including therapy with anti-inflammatory cytokines, transplantation of neural stem/precursor cells and induction of axonal regeneration.     

Somatostatinergic nerves in the cervical spinal cord of the monkey

Somatostatinergic nerves in the spinal cord of the monkey were investigated utilizing immunohistochemistry with various antibodies against synthetic somatostatin. In contrast to earlier investigations, it is shown that somatostatinergic nerve endings occur in most of the areas of the grey matter of the spinal cord. The somatostatinergic axons are, however, characteristically distributed in three main regions: (1) Densely-packed endings are seen in lamina II of the substantia gelatinosa, forming a crescent-shaped pattern in the columna dorsalis. Somatostatin immunoreactivity is also seen in lamina I and in the Lissauer tract. (2) A fine network of fibers is observed around the central canal; the endings are concentrated on special cell bodies. Some single perikarya are also stained in this region. (3) A loose network of single fibers is found ending on perikarya of the columna lateralis or ventralis. The perikarya of the nerve axons, with the exception of those terminating in the columna dorsalis, have as yet not been identified. In order to better understand the somatostatinergic system of the spinal cord, these newly-detected somatostatinergic nerves must be studied and their exact pathways analyzed.     

Animal models of spinal cord contusion injuries.

BACKGROUND AND PURPOSE: Traumatic spinal cord injury causes initial mechanical disruption of tissue, leading to a complex secondary sequence of pathophysiologic changes and neurologic impairment. These sequelae depend on the impact force delivered to the spinal cord at the time of injury. Successful clinical evaluation of the efficacy of any therapeutic regimen depends on the reliability and reproducibility of an experimental animal model. We describe a trauma device and the biomechanical parameters required to induce severe or moderate spinal cord contusion injury in cats and rats. METHODS: Recovery after injury was determined by behavioral, electrophysiologic, and histologic evaluations. RESULTS: Behavioral and electrophysiologic tests after injury clearly identified the experimental groups. A stable severe paraplegic state (defined as 6 months for cats and 8 weeks for rats), without evidence of behavioral or electrophysiologic recovery, was induced by a 65-Newton (N) load for cats and a 35-N load for rats. Moderate spinal cord contusion injury, from which cats and rats partially recovered after approximately 3 months and 4 weeks, respectively, was induced by a 45- and 25-N load, respectively. CONCLUSION: Use of these injury conditions provides reliable animal models for studies designed to evaluate potential therapeutic regimens for spinal cord injury.     

Phrenic nerve afferents elicited cord dorsum potential in the cat cervical spinal cord

Background  

The diaphragm has sensory innervation from mechanoreceptors with myelinated axons entering the spinal cord via the phrenic nerve that project to the thalamus and somatosensory cortex. It was hypothesized that phrenic nerve afferent (PnA) projection to the central nervous system is via the spinal dorsal column pathway.     

Existence of respiratory interneurons in the cervical spinal cord of the rabbit

A spinal "respiration" generator has been shown to fire phrenic motoneurones in rhythmic bursts. It is very likely driven through bulbo-spinal inspiratory neurones in intact preparations. Although no direct evidence for respiratory interneurones at the C4-C5 spinal levels has been obtained so far (except for Renshaw cells ), it is currently believed that only few inspiratory inputs to the phrenic motoneurones are transmitted monosynaptically from the medulla. We have tried here to record spinal interneuronal respiratory activities in decorticate, unanaesthetized, vagotomized and curarized rabbit preparations. Different functional categories of interneurones could be identified at the C4-C5 spinal levels: inspiratory and expiratory interneurons with various discharge patterns which rather well correspond to the functional categories of inspiratory and expiratory bulbo-spinal neurones described by Bianchi and Richter. In addition, multiunit inspiratory bursting could be followed over several 100 microns during each electrode penetration. The different categories of interneurones were encountered laterally from 700 to 1,000 microns, at depths ranging from 300 to 500 microns dorsally to the phrenic nucleus, down to the nucleus itself. These results indicate that part of the medullary inspiratory drive is channelled via spinal cord interneurones; they also suggest that an inhibition of phrenic motoneurones from the bulbo-spinal expiratory drive takes place via interneurones.     

Current concepts in the immediate management of acute spinal cord injuries.

The management of acute spinal cord injuries has changed considerably during the past 10 years owing to new information about the pathophysiology of cord trauma and new diagnostic and treatment methods. It is now known that the cord suffers not only from the immediate physical effects of trauma, but also from secondary pathologic processes, such as ischemia and edema, which are treatable in the first few hours after injury. New neuroradiologic and neurophysiological techniques, such as the recording of the somatosensory evoked potential, increase the accuracy of diagnosis and prognosis in the acute phase. Current immediate treatment includes the administration of steroids and mannitol, with careful attention to respiratory and cardiovascular homeostasis, to overcome post-traumatic ischemia and edema, and immobilization of the spine with devices such as the halo. New surgical procedures are used in selected cases to improve neurologic recovery, to provide rigid immobilization of the spine or to allow earlier mobilization of the patient. The care of spinal cord injuries in the acute phase is facilitated by multidisciplinary units.