"Head Injuries"
HEAD INJURIES
by Dr. Ken
The change in football rules at all levels, and especially the mandated
provisos regarding contact in the high school and collegiate games, has led to
a marked reduction in both head related, and cervical spine injuries. Reading
the first five installments of Helmet News, Safety First articles may have
left the reader with the impression that the modern football helmet does an
excellent job of protecting the head. It does but the number of head injuries,
with what we term concussion as the primary one, are still frequent enough to
be considered a serious problem. Troy Aikman, Steve Young, and others,
especially those at the quarterback position, have been especially vulnerable
and made concussion injury a "must issue" among NFL owners, players, and
medical staffs.
Let's have a quick summary:
-internal head injuries were the primary cause of on-the-field death prior
to 1960.
-with the introduction of the "modern" hard plastic helmet and metal
facemask, coaching philosophies and teaching techniques changed so that
headfirst hitting became the desired manner in which to make initial contact
upon blocking or tackling.
-by the mid-1970s, the primary cause of catastrophic on-the-field injury
had shifted from head, to cervical spine (neck) injury.
-In 1976, due in large part to the efforts of Dr. Joseph Torg of
Philadelphia, the high school and collegiate rules were changed in order to
outlaw or at least reduce, headfirst contact on all plays.
-the three primary mechanisms of injury were noted as: Direct Impact
between two moving bodies or Direct Impact between a moving body and a
stationary body where axial loading produced a destruction of spinal elements;
Deceleration Injury where the cervical spine was crushed between the head and
the still moving torso; Rotational Acceleration where the head was "torqued"
upon contact, leading to head injury, cervical spine injury, or both.
The above statements still hold true and although injuries to the head and
cervical spine have been reduced significantly, there are still injuries with
one fatality for every 1.5 million participants per year. The change in the
rules and the continued improvement in the helmet itself, have proven to be a
positive series of steps. I do not have a background in plastics, but when
those of us interested in helmet history think "plastic," I believe we
visualize John T. Riddell and his staff making the first plastic helmet with
materials that are like the ones we are familiar with today. This of course,
was not the case. The first "plastic helmet" was plastic, but it might be more
accurate to envision a resin impregnated fabric type material. Remember too
that the "first plastic football helmet" is credited as being developed in
1939, at the cusp of the War effort. With a shortage of plastics and materials
needed to manufacture plastics, the first plastic helmets I'm sure, were
nothing that any of us could imagine, or compare to today's materials.
Helmet manufacturing has always been a series of compromises. Plastic was,
and remains, lightweight relative to its size and our discussion of head and
cervical spine injuries indicated that "the less weight, the better." A
lighter football helmet will not fatigue the muscles of the neck and upper
back area as quickly as a heavier one. The more fatigued the muscles become,
the greater the probability of losing a proper head position when applying
contact. A lighter helmet provides less mass or weight and we will recall our
equation for creating rotational acceleration forces that can be so damaging
to both the brain structures and the cervical spine. The heavier helmet has
more mass and thus, more potential damage can result from rotational
acceleration. The helmet materials and construction must be strong so that it
can stand up to repeated blows, repetitive and accumulative damage. This
differs from the needs of a motorcycle or bicycle helmet which are constructed
with the intent of preventing a single, major damaging blow. The helmet must
be constructed so that the wearer can in fact, play the game of football. In
the office of the top researcher in the helmet safety field, I was shown a
huge, metal diving bell. There was no doubt, that packed with protective foam,
I was viewing "the safest helmet possible" for the wearer. Of course, one
could never play football in it, could never even realistically walk out of
the locker room while wearing it and don't even think about the damage
inflicted by trying to play in such a contraption, especially one made of
metal. This however, is part of the compromise of helmet construction; light
enough not to tire the involved muscles during play, strong enough to stand up
to repetitive blows, maintains its shape and function after contact, can be
maintained and reused for a reasonable period of time, fits comfortably and in
a manner that allows adequate vision, fits so that the safety features of the
helmet are in fact available to the user, is ventilated well enough so that
heat related illness does not become a factor (think again about the diving
bell type of helmet!), and is affordable to both manufacture in quantity and
then be purchased by the consumer. Thus, in order to produce a helmet that
meets safety requirements, an awful lot of thought and work has been done and
continues to be done.
While the safety considerations remain paramount, no matter how good the
helmet is at force attenuation, no matter what "accessories" also serve to
attenuate force (the so-called "hard" mouth guard and "hard" chinstrap with
six point security), and no matter how diligent coaches and players are
regarding the use of "safe" or "proper" tackling techniques, the helmet cannot
protect against all injuries, especially those due to rotational acceleration
as it affects the brain. More on this issue next month.