Technical and Biomechanical Data Regarding the L.E.X.BRACE
There are many organizations in the U.S. concerned about safety in sports. One such organization, The National Youth Sports Safety Foundation (NYSSF) in Boston, Massachusetts is an excellent example. In their Spring 2000 newsletter (Volume 9, No. 3) is an article entitled "Safety in Youth Sports - The Role of Standards, Personal Protective Equipment and Common Sense," authored by P. David Halstead. He is the technical director of the University of Tennessee Sports Biomechanics Impact Research Lab, College of Engineering, Department of Industrial Research Lab, Engineering Institute for Injury and Trauma Prevention, Knoxville, TN. The article points out that there are both governmental standards such as recommendations from the Consumer Product Safety Commission as well as voluntary or industry standards. Such standards have resulted in better and more protective helmets for both hockey and football as well as a requirement that they be used.
While not specifically mentioning the neck, the article makes some pertinent statements on head injury. It points out that there are at least two major causes of closed head injuries suffered by an athlete.
One is linear acceleration, defined as deceleration along a line as in when your head hits the ground at the end of a fall (this is another way of describing axial loading or vertical forces going along or down the straightened spine.)
Another type of closed head injury is described as rotational or angular acceleration (this is like the whiplash injury to the neck a football or hockey player gets when hit from behind unexpectedly or checked forcefully.)
A paragraph in the article states:"In the many serious head injuries it is the author's opinion that it is likely for both mechanisms to be present. From the protective equipment standpoint this is a potential quandary. In the rotational mode of injury a helmet may be of little or no value. In fact, having the added mass of a helmet on your head may be a bad thing depending on a variety of factors. But say, in the case of football, not having the helmet represents such a known and obvious risk that you must wear one."This statement is consistent with the fact that the added mass of a protective helmet on the head will concentrate and increase forces going through the neck, compared to the unhelmeted head.
The article concludes with a section on common sense, namely, instructing coaches and trainers to learn when a player should be taken out of a game for his/her own safety even if the player or a parent insists on further play.
The latest and most comprehensive textbook about this subject has just been published by W. B. Saunders Company. It is authored by Dr. Robert C. Cantu entitled "Neurologic Athletic Head and Spine Injuries". Dr. Cantu is Chief, Neurosurgery Service, Director, Service of Sports Medicine, Emerson Hospital, Concord, Massachusetts; Medical Director, National Center for Catastrophic Sports Injury Research, Chapel Hill, North Carolina. Many expert neurosurgeons, rehabilitation physicians, orthopedists, biomechanical physicians, and therapists from all over the U.S.A. have contributed to this authoritative textbook.
In his preface to the book, Dr. Cantu makes some very profound statements, two of which are quoted here:"Given the morbidity and the mortality associated with neurologic athletic head and spine injuries, it is obvious that prevention of these types of injuries is of paramount importance. Prevention starts with an understanding of the epidemiology of these injuries as well as with correct on-the-field evaluation. Prevention is also enhanced by an accurate diagnosis, prompt proper treatment, including rehabilitation, and correct return to play decisions.In Chapter 16 entitled Athletic Cervical Spinal Cord and Spine Injuries, a paragraph summarizes a very important theme that is repeated throughout the book. It states:
"A number of myths are discounted, such as that the football, baseball/softball, or lacrosse helmet protects the neck. These helmets are made to a NOCSAE standard to afford a significant degree of head protection, but they do not protect the neck (emphasis added)."
NOCSAE is the abbreviation for the National Operating Committee on Standards in Athletic Equipment."The pathomechanics of spine injuries in athletes appears to be similar regardless of the sport involved. Until the mid-1970s, hyperflexion of the cervical spine was thought to be the primary mechanism of spine injuries in athletes. However, careful analysis of these injuries by Torg and coworkers clearly established axial loading as the most common important biomechanical factor. Under normal circumstances, forces transmitted to the cervical spine are primarily dissipated by the cervical muscles, which allow for lateral bending, flexion, and extension. This force dissipation is most effective with the neck in an anatomic position - slightly extended because of normal cervical lordosis. However, when the neck is slightly flexed (approximately 30 degrees) and the normal lordosis is eliminated, the cervical spine becomes a single straight segmented column; thus any forces are transmitted directly to the bones, ligaments, and discs rather than to the muscles. When an athlete's head strikes another player, the ground, or the bottom of a pool, the cervical spine is compressed between the decelerated head and the force of the trunk. When sufficient force is applied, the bones, ligaments, or discs fail, resulting in various injuries."USA Hockey has been teaching the first and most important rule for safety is to keep your head up. The red schematic spine shown in these pictures demonstrates why. Namely, if the spine is straight, axial loading forces will cause greater injury. Dr. Alan Ashare (Director-at-Large USA Hockey; Chairman, Safety and Protective Equipment Committee USA Hockey), emphasizes this point in a widely distributed video called "Heads Up Hockey Challenge" produced by the USA Hockey Safety and Protective Equipment Committee. This concept is consistent with the description from Dr. Cantu's textbook.
The L.E.X.BRACE has been shown in initial biomechanical studies to be the only brace to reduce the severity index in both axial loading and frontal impact cases (To see Wayne State Biomechanical Observations click here).
P. David Halstead, during a telephone conversation with Dr. Hartunian, asked if the brace placed the neck in a position of potential danger. This led Dr. Hartunian to do some X-ray studies to evaluate this concern. A high school student, Ben Goodridge, who had been brought by his parents because of neck pain while playing football volunteered for this study.
Lateral spine films were taken of the player in a lineman-down stance without a brace and with the use of a L.E.X.BRACE, a "cowboy collar" and a "roll collar". The results are shown in the following sequence of pictures.
X-Ray set-up used to demonstrate cervical spine position in a lineman-down stance. Note that cervical curvature (lordosis) is maintained within red lines.
The L.E.X.BRACE allowed the most extension and maintained the cervical curvature (lordosis) as seen within the red lines. This is the safest position to withstand impact forces as demonstrated in the USA Hockey flier image encouraging "Heads-Up" play.
The cowboy collar blocks extension, straightening the cervical curvature (lordosis) as seen within the red lines. This places the spine in a position of the greatest danger from impact forces as demonstrated in the USA Hockey flier encouraging "Heads-Up" play.
The roll collar blocks extension, straightening the cervical curvature (lordosis) as seen within the red lines. This places the spine in a position of the greatest danger from impact forces as demonstrated in the USA Hockey flier encouraging "Heads-Up" play.
Dr. Hartunian has also measured an angle described as the B-H angle. The B-H angle is defined as the angle between the back of the player and the verticle to the helmet. This vertical point is where a plumb line perpendicular to the ground intersects the highest point of the helmet. For different players the B-H angle varied considerably from 35 degrees (Ben Goodridge - no brace) to 60 degrees in a player with greater neck mobility. For Ben Goodridge, the B-H angles were as follows:
Neck Device Used B-H Angle None 35 degrees Large L.E.X.BRACE 30 degrees Regular "cowboy collar" 15 degrees 1" "roll collar" with a 4" posterior roll 10 degrees
Evaluation of the lateral cervical spine X-rays with a radiologist supports the theory that a lower B-H angle is consistent with a straightening of the normal spinal lordosis. This places the cervical spine in a position of greater risk for the most dangerous injury-producing axial loading forces when applied to the helmet. This study is also completely consistent with the recommendations of USA Hockey which teaches the players to keep their heads up, maintaining the safer position of spinal lordosis, if they hit the boards.
When comparing the L.E.X.BRACE, "cowboy collar" and "roll collar" for a lineman-down stance, the L.E.X.BRACE allows enough extension to maintain the lordosis. The other braces, by blocking extension, straighten the lordosis, placing the neck in a position of inherent danger from an axial loading force.
Concussions in contact sports, especially football and hockey are becoming more frequent. The critical importance of recognizing signs and symptoms of this condition and limiting the athlete's play has been emphasized by many experts. A concussion can be thought of as a sudden disruption of brain activity affecting vision, clear thinking ability as well as consciousness. It is the result of a sudden great energy impact to the brain and brainstem.
This is understandable since the energy of tackles and hits is increasing in direct proportion to the mass or weight of a player and even more to the greater speed (square power of velocity) of the athletes. We all know that today's athletes are bigger and faster than ever. Two mechanisms have been described as the cause for concussions.
One mechanism is impact loading, essentially, a direct blow to the head resulting in a high energy input over a short period of time. A second mechanism is impulsive loading, which can be thought of as the whiplash-like motion to the head and neck during tackles or hits. Rapid acceleration/deceleration and rotational forces are involved.
While the helmet affords some protection to impact loading, it does not provide protection against impulsive loading. The sudden back and forth motion of the head, particularly in a lateral direction with rotation, is believed to cause the most significant injury.
The L.E.X.BRACE, by surrounding the neck for a full 360 degrees, will likely reduce impulsive loading in two ways. First, it will decrease the lateral back and forth motion of the head/neck as the helmet hits the inclined inner surface of the brace. Second, rotational forces will be reduced as the edge of the helmet compresses into the foam locking the helmet to the shoulder area resulting in a more diffuse distribution of energy through the body.
This is consistent with the concept that a player is less likely to incur a neck injury if he/she maintains a heads up position and is tensing the neck muscles in preparation for the hit. The muscular action makes the head rigidly fixed to the body for better distribution of energy. The concussion of impulsive loading usually occurs when the player is unexpectedly hit and the neck muscles are relatively relaxed. In a contact or compressive state, the L.E.X.BRACE can fill the gap between the helmet and shoulders minimizing this type of concussion.
It is clear that better neck protection is needed in high speed and contact sports requiring helmets. Fortunately, the tragic cases of paralysis are low in numbers. However, 50% of athletes, such as football and hockey players, get nerve impingement symptoms called "stingers" in their years of play, making the long term effects of arthritis and chronic nerve injury much greater. Costs to society in pain/suffering can be reduced with better neck protection.
The US Product safety Commission has recommended that all downhill skiers and snowboarders wear helmets to reduce head injury. Provided the helmets are designed properly, the L.E.X.BRACE would be beneficial in minimizing neck injury while participating in these recreational sports. The fact is, any sport where a helmet is recommended for head protection would benefit from the use of the L.E.X.BRACE as long as the helmet is shaped like a football helmet. This would allow the necessary close fit between the firm bottom edge of the helmet and the L.E.X.BRACE.
If "freedom" from the use of proper protective equipment or if "stylish" but ineffective equipment is allowed to be used in high speed and contact sports, greater neck injuries and concussions will result.
There are some who believe that the use of more protective equipment results in more reckless play by the athlete, perhaps increasing injury. Many professionals, including Dr. Hartunian, strongly disagree with this sentiment. They believe an athlete will play more effectively while feeling more secure, knowing he/she is using the best protective equipment. It is the responsibility of the coaches to continually teach safe play and the referees to enforce rules of safe play, penalizing an athlete who performs recklessly.
The L.E.X.BRACE is the best designed sports neck brace to accomplish a reduction in neck injuries and concussions in contact and high speed sports requiring helmets. Through this web site, Dr. Hartunian hopes to make more people aware of this growing problem. Additional testing still needs to be done, and hopefully, funding will be obtained to prove that the L.E.X.BRACE should become a standard part of required safety athletic equipment.