4. Common types of Spinal Cord Injury
The spinal cord itself is an extension of the brain, a long bundle of nerve cells and fibers wrapped together (like high-speed internet, fiber-optic cable) that runs through the bony center of the vertebral column, extending down from the brain stem to the lower back. The cord acts as a communication conduit for the brain to send bio-electrical signals through, giving instructions to the arms, legs, feet, hands and all other areas of the body.
5. Levels of Spinal Cord Injury
Understanding the mechanisms involved, testing the effectiveness in animals, running clinical trials in humans – the development of a treatment is a slow and complicated process. For now at least, transplantation therapy holds the greatest promise for the treatment of spinal cord injury with stem cells. In 2010, the Californian company based on this approach, although it was halted at an early stage for financial reasons. Currently, using cells derived from human brain tissue. The hope is that when transplanted into the injured spinal cord, these cells may re-establish some of the circuitry important for the network of nerves that carry information around the body.
Spinal cord injury is a very common and devastating disease process that can occur as a consequence of motor vehicle collisions, falls or other traumatic injuries. Cardiac disorders are common consequences following SCI. Cardiovascular disturbances are the leading causes of morbidity and mortality in both acute and chronic phases of SCI. Disruption of descendent pathways from superior centers to spinal sympathetic neurons, originating into the intermediolateral nuclei of T1- L2 spinal cord segments results in a reduced overall sympathetic activity and unopposed parasympathetic activity. As a result, the most common cardiac dysrrhythmia is bradycardia. There are a few well established therapeutic modalities (Table 1) for the treatment of bradycardia associated with cervical SCI. All therapeutic options are based on anecdotal reports and small retrospective reviews. Atropine should be kept readily available at the bedside at all times. Based on recent evidence with methylxanthines, we recommend further studies to establish the role of these agents as a first line therapy in this specific patient population. Optimal dose and duration of therapy need to be established. Theophylline’s use via entral route as a first line therapy for spinal cord injury-related bradycardia can help avoid the long term use of inotropic and chronotropic infusions and their associated risks and complications, as well as prevent and/or decrease the use of cardiac pacemaker placement and its associated procedural risks and complications. We further recommend the study of xanthine derivates as prophylactic treatment for the first 2-6 weeks of the injury based on the frequency of bradycardia in patients with cervical SCI which is reported to be 100%. Currently, there are no established guidelines regarding permanent pacemaker placement in this patient population. Permanent pacemaker should still be considered in patients with refractory or recurrent bradycardia more than two weeks after the injury. In addition, the incidence of bradycardia after cervical SCI may be decreased by proper prophylactic measures, cardiac exercises and appropriate rehabilitation.
9. Causes of Spinal Cord Injury
Non-neural adult stem cells are extracted from various tissues, such as bone marrow, adipose tissue and the placenta. It is thought that these stem cells help repair the injured spinal cord indirectly. Many studies show that animals are able to better move and feel after transplantation of these cells ().
Traumatic injury or Spinal cord stem cell research
Neural stem cells are extracted from certain parts of the nervous systems of embryos or adults. Many studies have shown that the transplanted cells differentiate into astrocytes that help new neural cells to grow (; ). Research published last year suggests that neural stem cells can re-programme the local inflammatory response to injury, reducing the proportion of harmful immune cells (such as macrophages), while promoting healing of the injured spinal cord (). In most studies that have looked at recovery after neural stem cell transplantation, the animals were better able to move their legs.
The incidence and prevalence of spinal cord injury in Canada.
Given the multifaceted nature of spinal cord injury, it is unlikely that any one treatment will provide a cure, but even small improvements would make a big difference to patients’ lives. Imagine if, like Christopher Reeve, you were paralysed from the neck downwards: being able to move your arms and grip with your hands could make the difference between living a dependent or independent life.
Overview of the Prevalence of Spinal Cord Injury in Canada.
Cardiovascular instability is a frequent complication of SCI, especially when the upper thoracic or cervical cord is involved (Figure 1). Peripheral sympathetic denervation results in arteriolar dilation and pooling of blood in the venous compartment, while interruption of cardiac sympathetic innervation (T1- T4) promotes bradycardia (Figure 2) and reduces myocardial contractility. The autonomic nervous system modulates cardiac electrophysiology, and, consequently, autonomic dysfunction can lead to ventricular arrhythmias. Concomitantly, parasympathetic input to the heart (from the vagus nerve, cranial nerve [CN] X) remains intact and may frequently result in bradycardia, especially with cervical SCI. Less commonly, cardiac arrest has been documented. Bradycardia is often precipitated by tracheal stimulation (for example, during suctioning) and hypoxia (Mathias et al, 1976; Piepmeier et al, 1985). Reflex bradycardia and cardiac arrest occur due to a vago-vagal reflex. Under normal circumstances, this reflex is opposed by sympathetic activity. As a compensatory response to hypoxia, a pulmonary-vagal reflex occurs, designed to increase respiratory rate and pulmonary inflation. However, in patients with SCI, compensatory sympathetic activity is eliminated, leaving parasympathetic activity unopposed, leading to severe bradycardia and potentially cardiac arrest. Studies of cardiovascular abnormalities after SCI show that as many as 100% of patients with motor complete cervical injuries (American Spinal Injury Association [ASIA] grades A and B) develop bradycardia, 68% are hypotensive, 35% require pressors, and 16% have primary cardiac arrest. Of persons with motor incomplete cervical injuries (ASIA grades C and D), 35-71% develop bradycardia, but few have hypotension or require pressors. Among patients with thoracolumbar injuries, 13-35% have bradycardia (Lehmann et al, 1987; Wirth et al, 2007). Bradycardia is more frequently encountered in the acute phase, and is more severe in the first 2-6 weeks after trauma (Krassioukov et al, 2007; McKinley et al, 2006). Cardiovascular dysfunctions improve in time. The reasons are not well understood, but synaptic reorganization or hyperresponsiveness of alpha receptors may play a role (Gondim et al, 2004).