In my years of taking care of athletes from grade school to the professional ranks, few injuries can be more worrisome than those involving the cervical spine. Given the possibility of devastating consequences associated with cervical injuries, such problems require careful evaluation to assess the extent of damage done and the safety to continue to participate in the sporting activity. Spinal cord injuries may be divided between complete, or permanent injuries and those termed temporary. Injuries to the spinal cord which are temporary are called neuropraxic, or essentially bruising, type injuries. The phenomenon of transient neurapraxia was first described by Joseph S. Torg, M.D., in 1986, based on the information gathered from the National Football Head and Neck Injury Registry established in 1975. Transient cervical neurapraxia is characterized by paresthesias (tingling) or weakness in the arms or legs. Episodes typically improve within a minute or so of the initial injury and generally resolve completely.

Most cases seem to be related to high velocity, high impact sports such as football or hockey. Elite or professional athletes are prone to such injuries given the greater forces associated with such collisions, however, athletes at all levels may be at risk. The common causative position occurs when the athlete makes contact with the head down or in the flexed position. Such a position, reminiscent of the speartackling technique popularized in the professional football ranks, causes the forces to be distributed to the neck as an axial load. This is similar to pressing directly down upon the head. Unfortunately, the neck is poorly equipped to handle such forces. Good technique may avert disasters, but no player is immune. The problem most commonly affects defensive backs in football and defensemen in hockey as a result of the type of collisions they incur.

As a result of Dr. Torg’s findings, “spearing,” or lowering the head and hitting an opponent with the crown of the helmet, has been outlawed by the National Football League and throughout most levels of football. Lowering the head reverses the normal curvature of the cervical spine, resulting in a straightening of the neck so that it is unable to adequately absorb the impact, often resulting in an injury to the spinal cord.

“Most cases occur on the football field, following a severe collision in which the athlete’s neck is either axially loaded or forcefully extended.” -Dr. Brian R. Subach, The Virginia Spine Institute

Unfortunately neuropraxia often occurs in a structurally normal spine. It may also be associated with conditions which result in a functional narrowing of the spinal canal, such as disc herniations, congenital spinal stenosis, acquired stenosis due to degenerative changes, or instability due to laxity in the ligaments. In contrast to a neuropraxic cord injury, the common “stinger” is characterized by numbness, burning, or electrical shock-like sensations in one arm after an impact. This is thought to be caused by either a stretch or compression of the brachial plexus. Since it is typically temporary and resolves without intervention, most stingers are treated conservatively and simply observed.

When a player is down on the field the team physician must determine the presence of head or spine injuries. If there is any concern about a spinal cord injury, immediate action must be taken to immobilize the head and neck, then ensure safe transport off the field and to the hospital for evaluation. In cases of spinal cord injury, neuropraxic or more severe, emergency interventions with medications and imaging studies may be necessary. If the symptoms resolve quickly, the athlete should be restricted from play until an appropriate evaluation can be carried out by a neurosurgeon or qualified orthopaedic spinal specialist.

The evaluation generally includes a complete neurological evaluation and a radiographic assessment for structural abnormalities in the cervical spine. Routine cervical X-rays and a magnetic resonance image (MRI) are often necessary to identify injury or damage.

Those of us treating sport-related injuries and neuropraxic damage do not belive that such episodes of bruising actually lead to paralysis, since no player with neurapraxia from the National Football Head and Neck Registry has subsequently gone on to permanently lose function. In addition, none of the players sustaining a permanent spinal cord injury could ever recall a prior warning episode of neuropraxia.

Left: T2-weighted sagittal MRI of a professional football player who sustained an episode of transient cervical neurapraxia following a collision as wide receiver. Note the relative lack of high-signal-intensity spinal fluid surrounding the spinal cord.

Right: Sagittal MRI of a rugby player with an os odontoideum who sustained an episode of cervical neurapraxia during a game. T2-weighted  sagittal MRI of thesame player shows an area of increased signal intensity opposite the os odontoideum, representing edema from a spinal cord contusion.

In counseling athletes, they should be informed that after a single episode of transient cervical neurapraxia, they face an approximate 50 percent chance of a repeat episode if they choose to continue playing. Should any structural abnormalities be identified, the Virginia Spine Institute generally recommends that the athlete not return to a collision sport. In the absence of structural abnormalities, many high-school and recreational athletes will give up the sport rather than risk the possibility of injury. At the collegiate and professional levels, players must contend with scholarships, careers, and financial futures. In these cases, Dr. Torg’s 1997 study identified a return to play rate of 60% for athletes sustaining a neuropraxic injury in a contact sport.

Some players explore surgical options in order to continue playing, with a reduced risk of neurapraxia or permanent cord injury. If a patient has a disc herniation, for instance, diskectomy and fusion may be considered. It should be emphasized that no surgery will completely eliminate such risks. Rather, surgery may destabilize the spine or limit essential flexibility, thereby possibly placing the athlete at even greater risk.