Brilliant Blue G Dye as a Spinal Cord Injury Treatment

Overview of the Spinal Cord

The spinal cord is a thick, elongated bundle of nervous tissue enclosed within the vertebral column, or spine, extending from the base of the brain to the rest of the body (Laberge 2010). Its chief function is to carry nerve impulses between the brain and the rest of the body. Together, the brain and spinal cord form the central nervous system (CNS). The spinal cord is a critical CNS component, serving as the link between the brain and the spinal nerves that connect to muscles and body organs. The motor and sensory nerves that make up the peripheral nervous system (PNS) also depend on this link. In addition to relaying voluntary commands, the spinal cord transmits messages to body organs that perform involuntary or automatic functions — including the regulation of chemical contents in the blood and body fluids, as well as the regulation of the heart, stomach, and intestines — through an automatic control system involving the spinal cord and its network (Laberge).

The spinal cord is subject to trauma, diseases, and disorders. Trauma to the vertebral column can injure the spinal cord, compressing nerves and leading to muscle weakness, abnormal sensations, or even a torn or severed cord and paralysis (Laberge 2010). Severe injuries can impair or destroy spinal cord functions entirely. A damaged spinal cord can cut off sensation, motor function, or both, below the level of injury. The higher the level of injury, the more severe — and potentially fatal — the consequence. Other disorders affecting the spinal cord include epidural abscesses, foraminal stenosis, pinched nerves, sciatica, and spinal stenosis (Laberge).

Spinal Cord Injuries: Classification and Statistics

Spinal cord injuries are often permanent and cause significant nerve deficiency and disability (Schreiber 2009). According to the National Institutes of Health, their economic and social costs are exceeded only by those of mental retardation. These injuries are classified as either primary or secondary. Primary spinal cord injuries involve mechanical disruption, transection, and distraction of neural elements; they occur with fracture, spinal dislocation, penetration by bullets or weapons, or extradural infections. Primary spinal injuries may, however, occur without spinal fracture or dislocation. Secondary spinal cord injuries are vascular in nature, typically caused by arterial disruption, arterial thrombosis, or hypoperfusion due to shock. Both primary and secondary injuries may be complete or incomplete. A complete injury involves total clinical loss of motor and sensory function below the level of injury; an incomplete injury involves only partial loss of sensory and/or motor function below that level (Schreiber).

Approximately 40 cases per million people — or roughly 12,000 patients per year — suffer spinal cord injuries, according to the National Spinal Cord Injury database (Schreiber 2009). The number of survivors continues to increase, though their life expectancy remains below that of the general population. The 2003 U.S. Life Tables show that a healthy 20-year-old can expect to live to 78.4 years, while a 20-year-old quadriplegic may live only to age 60. According to 2000 statistics, 63% of those who suffered spinal cord injuries were Caucasian, male at a 4:1 ratio, and approximately half were aged 16 to 30. The most common causes were motor vehicle accidents, falls, gunshot wounds, and sports injuries. Motor vehicle accidents were frequently linked to drunk driving or alcohol and drug abuse. These patients are best treated at a regional spinal cord injury center.

Patients with complete spinal cord injuries have only a 5% chance of recovery. Those whose paralysis persists at 72 hours have essentially zero chance. Outcomes are better for incomplete cord syndromes: recovery odds exceed 50% if some sensory function is preserved, and up to 90% of such patients will eventually regain independent walking. These figures are encouraging given that the mortality rate for complete injuries was nearly 100% in the early 1900s. The introduction of antibiotics to treat pneumonia and urinary tract infections deserves significant credit for improved survival. The five-year survival rate for traumatic quadriplegia is now 89%, and hospital mortality rates have reached historically low levels (Schreiber).