Emerging therapies for acute traumatic spinal cord injury

There are currently about 85 000 Canadians living with spinal cord injuries, more than half of which are secondary to trauma.1 As the population ages, the incidence and prevalence of traumatic spinal cord injury are expected to increase, primarily as a result of fall-related injuries among older adults2. Therefore, treating spinal cord injuries is relevant not only to spine surgeons and physiatrists, but also to the general clinician who will increasingly encounter such patients in the emergency department or family practice. The initial trauma, or primary injury to the spinal cord, starts a sequence of pathological events collectively referred to as secondary injury. These secondary mechanisms begin within seconds of the primary injury and continue for several weeks thereafter, leading to an expanded region of tissue destruction (Figure 1). The initial disruption of the spinal cord vasculature leads to the development of microhemorrhages in the grey and white matter, interstitial edema and the release of coagulation factors and vasoactive amines.3 These events promote thrombosis and vasospasm of the microvasculature of the spinal cord causing tissue hypoxia and impaired neuronal homeostasis. At the cellular level, impairments include ionic imbalance, peroxidation of membrane lipids, formation of free radicals and release of toxic levels of the excitatory neurotransmitter glutamate.4 Neuroprotective agents act to mitigate secondary injury mechanisms to reduce the extent of neural damage. We performed a comprehensive literature search of MEDLINE for the key words "spinal cord injury" and the medical subheading "treatment." We limited the search to clinical articles published between 1980 and 2012 in English journals. We excluded studies involving animals, review articles and case reports. We supplemented this strategy by searching the Cochrane Database of Systematic Reviews for the term "spinal cord injury." We identified and reviewed 401 abstracts for relevance to the topic. We selected 45 abstracts for which we obtained the full-text version to use as the basis for this review. In addition, we reviewed the 2002 American Association of Neurological Surgeons/Congress of Neurological Surgeons cervical spinal cord injury consensus guidelines, as well as the Consortium for Spinal Cord Medicine 2008 spinal cord injury early acute management clinical practice guidelines.