1. Field of the Invention
The invention is directed to a cervical spine protection apparatus and methods for use thereof. The invention may be useful for stabilizing the spine, particularly by facilitating the rehabilitation of or preventing and/or minimizing the occurrence and/or severity of spinal injuries, particularly cervical spine injuries.
2. Description of the Related Technology
High impact sports pose a substantial risk for head and spinal injuries. During a typical game of high school tackle football, about 40.5 head impacts occur per hour, and about 24.4 head impacts occur per hour during a typical game of high school hockey. Studies of helmet-to-helmet collisions in the National Football League (NFL) using hybrid III dummies found that during collision, an athlete's head experiences a change in velocity of about 7.2±18 m/s, a translational acceleration of about 94.3±27.5 g and a rotational acceleration of about 6432±1813 r/s2 during impact. Although helmets offer some degree of protection for the head, they do not adequately safeguard the wearer from traumatic spinal injuries, particularly cervical spine injuries. To the contrary, the National Football Head and Neck Injury Registry concluded that helmets can increase the risk of neck injuries when athletes use the helmet as a weapon. For example, practices such as “spearing” can induce axial load tear drop fracture that may cause a wide range of neurological disorders, including quadriplegia. During 1945-2004, 497 deaths were caused by playing tackle football in the United States, 16% of which were attributed to spinal cord injuries; the annual incidence rate of permanent cervical spinal cord injuries was about 0.55 per 100,000 among tackle football players.
In general, injuries to the cervical spine may occur when impact or inertial forces acting on the head are large enough to deform the underlying connective tissues beyond their tolerance limits. When placed under extreme loading and functional demands induced by high impact sports, contortions of the soft tissue allow the cervical spine to assume injurious positions. The primary factors that contribute to neck injury are high torque jolts, the proximity of the neck to the anatomical joint limits, muscular fatigue and insufficiency, and the properties of the head mounted load. For example, cervical cord neurapraxia, which causes temporary paralysis as well as a radiating burning pain, numbness or tingling in the arm, is a common cervical spine injury incurred during high impact sports. Caused by traction injury to the brachial plexus, percussive injury to the upper trunk and/or nerve compression when the neck undergoes a combination of hyperextension and ipsilateral lateral rotation, cervical cord neurapraxia has a high incidence rate of 7 per 10,000 football participants and a high recurrence rate of about 56%. About 65% of college football players sustain at least one cervical cord neurapraxia injury during their college careers.
The risk of traumatic cervical spine injuries, such as cervical cord neurapraxia, is even higher in children and adolescents than adults. Due to the slower development of the cervical spine and the surrounding musculature relative to the anatomical development of the head, children and adolescents are more prone to cervical spine injuries. Additionally, the specific biomechanical characteristics of pediatric cervical spines increase the likelihood of incurring severe neurological damage.
Despite the overwhelming documented epidemiological evidence of the high incidence rate of cervical spine injuries caused by high impact sports, no apparatus currently exists to protect a user from incurring such injuries. Conventional neck protection devices, such as the cowboy collar, bullock collar, kerr collar and neck roll, are generally ineffective in protecting the wearer from a wide range of loading situations and neck injuries experienced by different players, such as quarterbacks and linemen, during football. Notably, these devices do not meet the performance requirements nor mitigate the risks associated with the various different positions in football. Furthermore, there is no means for customizing the device to the preference, physiological dimensions and biomechanics, or intended use of a wearer. Of these devices, experiments have shown that the cowboy collar is the only apparatus that has been found to be partially effective against hyper-extension of the neck. None of these devices, however, were effective in preventing other forms of forced movement, such as lateral bending or axial rotation. Furthermore, these devices tend to be bulky, substantially limit the natural range of motion of an athlete's head and interfere with athletic performance.
Additionally, neck exercisers and protectors that include conventional spring elements, such as that disclosed in U.S. Pat. No. 4,219,193, and head stabilizing systems incorporating hydraulic pistons, such as that disclosed in U.S. Pat. No. 6,968,576, are also inadequate in protecting against, or rehabilitating cervical spine injuries. The conventional spring and hydraulic mechanism of these devices fails to provide adequate resistance at the extreme ranges of motion of the cervical spine to prevent injury and also substantially interfere with and inhibit the wearer's range of motion. Additionally, the arrangement of the springs and dampening mechanisms of these patents are inadequate for protecting a wearer from a wide range of cervical spine injuries.
Therefore there is a need to develop a suitable apparatus capable of reducing the risk of a wide variety of cervical spine injuries by dynamically limiting the motion of the cervical spine to a functional and non-injurious range of motion without substantially limiting the wearer's normal range of motion.