Nice article.  If I did not have a full face helmet during my accident, I would not have a right face or ear, which would make me uglier, not to mention possibly dumber then I already am (a truely scary thought). 

Good luck and ride safe,

Mike

Thanks for writing this article.  I ditto Mike's response.  I think when enough of us get together to accomplish a common goal, we can make it happen.  We have many hurdles to climb, but with persistence, we may see it happen. 

Thanks again.

Ride Safe,

 M. Wiggins  CA 
 

Excellent article.  I do like to see freedom of choice.  After all its your head but you should be able to foot the bill if you injure it.  I started riding with a full face helmet and still always wear one on every ride.  The protection from flying debri, weather and comfort is worth it even if you never crash.  I have ridden with many that don't wear a helmet and have heard many complaints of discomfort.  I also have ridden with some that raz me to no end for wearing one, what happened to freedom of choice there?  Why do those who decide not to wear one try to discourage others who choose to? 

Maggie

Maggie:

Why do those who decide not to wear one try to discourage others who choose to? 

 Because they are so clueless about how effective a helmet is.They hear from others that helmets can cause injuries despite all the proof that they dont and just go along with the crowd. To say a helmet causes injuries is like saying a bullet proof vest does too. I am all for an adults right to pick what they wear but it is truly sad to see someone ride without based on false information. Any rider who would discourage you from wearing proper gear just needs to find another hobby where they cant get someone killed from their ignorance.

RODNEY D. COOTER MB, BS, (Adel)
Registrar
The Australian Craniofacial Unit
Adelaide Children's Hospital and Royal Adelaide Hospital
Australia

DAVID J. DAVID AC, MBBS (Adel), FRCS, FRCSE,
FRACS
Head of Unit
The Australian Craniofacial Unit
Adelaide Children's Hospital and Royal Adelaide Hospital
Australia

ABSTRACT

Craniofacial fracture patterns were investigated in hospitalized patients and fatally injured subjects to determine the influence of helmets, spectacles, and dentures. Standardized clinical and radiographic assessment techniques were developed and fracture patterns were recorded at operation or necropsy. All fracture data were encoded into an alpha-numerical system for analysis.

From the hospitalized group interesting associations emerged of naso-ethmoidal fracturing with spectacle wearing and maxillary fracturing with denture wearing. Hospitalized motorcyclists who had worn open-face helmets, or full-face helmets with flexible face-bars, had sustained facial fracturing but minimal brain injury. In contrast, motorcyclists killed from anterior craniofacial impact whilst wearing full-face helmets with rigid face-bars had sustained fatal skull base fracturing in the absence of significant facial trauma.

It was therefore postulated that impacts to the face-bar of a full-face helmet may be transmitted through the mandibular rami and mandibular condyles to the skull base with subsequent fracturing of the middle cranial fossa, the integrity of the mid-facial skeleton being preserved.

Helmet deformation patterns, as delineated by computed tomography, provided support for the proposed mechanism of energy transfer to the skull base. Independent neuropathological examinations of the brains of the fatally injured motorcyclists revealed a high incidence of ponto-medullary disruption. This further strengthened the postulate because separation of the robust pons from the slender medulla may result from axial traction imparted to the brainstem by an upward fracturing middle cranial fossa shelf. Furthermore the skull base fractures traversed the mid-line through, or near to, the spheno-occipital synchondrosis which has an heterogenous morphology and is part of a potential 'fault line' across the skull base. That such a skull base fracture can occur from upward impaction of the skull base by column loading of the mandibular ramus has been noted in reports of judicial hangings in which the knot was placed beneath the mandibular angle.

From this study it was concluded that objects worn at impact on the craniofacial region may influence significantly the final craniofacial fracture pattern and this may be detrimental for some motorcyclists wearing full-face helmets.

INTRODUCTION

The labyrinthine architecture of human facial bones provides a propensity for their collapse at impact and they may thereby act as an effective energy absorber by preventing injury to the brain.⁽¹⁾ This concept is frequently reinforced by clinical observations of patients who have severe facial fracturing but only minimal overt brain injury. The cushioning potential of facial fracturing was recorded by Le Fort in 1901⁽²⁾ whilst reporting on his experiments to delineate the lines of mechanical weakness in facial bones. In a similar way, in the 1940's, Cairns and Holbourn⁽³⁾ noted the sparing of brain injury in helmeted motorcyclists who had sustained facial fractures. In contrast to the present-day surgical enthusiasm to devise new reparative techniques for facial fractures, only scant attention has been given to an analysis of observed fracture patterns and their potential mechanisms of production. One area that has remained void of investigation has been the influence on subsequent craniofacial fracture patterns of objects fitted to the craniofacial region ; in particular, objects such as helmets, spectacles, and dentures. This is surprising because these are commonly worn by people sustaining facial trauma. Whilst considering that facial fractures may actually play a protective role for the brain by absorbing impact energy, it is interesting to note that motorcycle helmet manufacturers have determined to produce helmets that incorporate a face-bar which is designed to prevent facial trauma. So popular have full-face helmets become that over 80% of motorcyclists wear them.⁽⁴⁾ However, disturbing international reports are now emerging of inexplicable skull base fracturing in fatally injured motorcyclists wearing full-face helmets. ^(5-9)

OBJECTIVE

With the foregoing in mind, one objective of the present study was to compare and contrast the patterns of fracturing within the craniofacial region of surviving motorcyclists with those of fatally injured motorcyclists in an endeavour to elucidate a mechanism responsible for the fatal skull base fracturing that has been reported in full- face helmet wearers.

METHODOLOGY

To effect an analysis of fracture patterns with due regard for the complex anatomy of the craniofacial region required the formulation of an accurate method to code numerically the bony disruption. An alpha-numerical coding system was devised⁽¹⁰⁾ and this was employed to analyse fracture data obtained from a variety of sources including clinical examination, radiographs, and operative, as well as post-mortem examinations.

A systematic method was developed for the clinical examination of the traumatized craniofacial. region of 50 hospitalized patients. Furthermore an optimal combination of radiographic imaging was ascertained and computed tomography (CT) was found to be the single most informative mode of imaging. Using the clinicoradiographic methods so devised, the fracture information of clinical patients was then coded into the alpha- numerical system. Road accident details were also collected and the influence assessed of objects fitted to the craniofacial region. Interesting associations emerged. High numerical scores of fracturing in the naso-ethmoidal region were associated with the wearing of heavy framed spectacles by four patients who had sustained lateral or oblique impacts. High numerical scores of fracturing in the maxillary region were associated with the wearing of upper dentures by six patients who had received impacts to the upper lip region. These preliminary studies demonstrated that the alphanumerical coding system was an effective method for the analysis of a wide range of fracture variants and also that the chosen clinical and radiographic techniques were providing accurate data efficiently, and that road traffic details could be incorporated with clinical details to generate meaningful associations about simple objects fitted to the craniofacial region.

Equipped with these techniques it was then considered appropriate to examine a series of 24 fatally-injured subjects, with particular reference to motorcyclists. With permission from the State Coroner, road traffic accident victims were examined with the palpation sequence of the systematic clinical examination method developed for clinical patients. If the clinical examination suggested the presence of craniofacial fracturing and other selection criteria were met, then the cadaver was transferred to a CT scanning facility and scanned according to the protocol devised for clinical patients. The cadavers then underwent a routine postmortem examination after which a formal facial dissection was performed using standard surgical approaches. Anthropomorphic landmarks were measured on the skull-base and the physical distances to fracture lines ascertained. In addition, the helmets worn by motorcyclists were uniquely examined with a CT scanning sequence that was developed for this project⁽¹¹⁾.

FINDINGS

When compared with the hospitalized group of motorcyclists the alpha-numerical coding of the fatally injured group revealed a statistically significant difference between their craniofacial injury patterns. The hospitalized group had high scores of facial fracturing but low scores of cranial fracturing. In contrast, fatally injured motorcyclists who had received impacts to the facial region whilst wearing full face helmets had sustained unsurvivable skull base fracturing (Figure 1), but low scores of facial fracturing were recorded. Indeed their observed skull base fractures traversed the middle cranial fossa just posterior to the underlying temporo-mandibular joints (Figure 2). Post-mortem, anthropomorphic data and dissection information of the cranial base and computed tomographic reformats of the craniofacial skeleton distraction patterns provided a foundation for a postulated mechanism to explain the fatal skull base fracturing.

It was proposed that an impact to the face bar of a motorcyclists' helmet may load the chinstrap, which is mounted at the rear of the facebar, and that this would transmit the force to the mandibular condyles and such force - loading would be sufficient to cause fracturing of the skull base^{(l 2)} -(Figure 3).Helmet deformation patterns observed using computed tomography provided further support for the proposed mechanism.

These findings stimulated further investigations to test the validity of the proposed mechanism of injury production. Routine neuropathological reports were retrieved of examinations of the brains of the fatally injured. In the sample studied, a high incidence of tearing at the junction of the pons and medulla further strengthened the proposed sequence of face bar - chin strap - mandibular condyle - skull base force transmission because it was anticipated that fracturing of the clivus with upward distraction of fracture edges should cause brain stem damage. This became the catalyst for a thorough independent search (co-ordinated by Professor Simpson - Neurosurgeon, The University of Adelaide Road Accident Research Unit) for ponto-medullary trauma in fatally injured road accident victims⁽¹³⁾.

From a consecutive series of 988 brains from autopsies on road accident victims there were 36 cases of unequivocal gross brain stem tearing. The proportion of motorcyclists was double the expected figure and of the 15 motorcyclists, 13 were known to have been wearing helmets at impact and 11 of these wore full face helmets. Furthermore, the principal impact point was the face or helmet face bar in nine of the motorcyclists.

The possibility remained that these injuries could still have been the result of severe cervical hyperextension rather than an upward impacting force through the mandibular condyles to the skull base. From a review of the craniofacial fracture patterns of people who had sustained an upward impacting force to their mandible it was interesting to note that the victims of judicial hangings in which the knot was placed beneath the angle of the mandible (thus imparting to the skull base an upward impacting force) could sustain fatal skull base fracturing of a similar ipsilateral pattern to that observed in the motorcyclist series. This contrasted significantly with the judicial hanging injury pattern observed in those victims who were hanged with the knot placed beneath the chin (thus providing a severe cervical hyperextension force) as they sustained fractures of their axis⁽¹⁴⁾.

Another potential source of support for the postulated mechanism of skull base fracturing relates to the spheno-occipital synchondrosis as it was through, or near to, this zone that the fractures traversed the clivus. The motorcyclist group (and most victims of judicial hangings) are usually males in the age range of 17 to 25 years. In this age group the spheno-occipital synchondrosis may be a weak zone because it is undergoing ossification and often has heterogeneous morphology. Interestingly two children who were investigated in this study after receiving fatal injuries from facial impacts at the mandibular level had both disrupted their spheno-occipital synchondrosis.

CONCLUSIONS AND FUTURE IMPLICATIONS

So from this investigation a mechanism has been postulated for the generation of fatal skull base fracturing in motorcyclists who sustain impacts at face level whilst wearing full-face helmets. To arrive at this postulate a new method has been developed for the coding of fractures in the craniofacial region, a systematic clinical examination process has been formulated, and an optimal sequence was derived for the radiographic imaging of craniofacial trauma. These techniques have been applied to a sample of clinical patients with fracturing and by incorporating road accident information, associations were then made between the wearing of simple objects (such as dentures and spectacles) and the final fracture patterns. From the application of these methods to a group of fatally injured motorcyclists a postulated mechanism has been advanced to explain the disturbingly high incidence of skull base fractures observed internationally in motorcyclists killed whilst wearing full-face helmets. Support for the postulate has been drawn from the CT scanning of helmets and also from an independent study of ponto-medullary injuries as well as reported observations of the injuries sustained by judicial hanging victims.

From this study it was concluded that objects worn. at impact on the craniofacial region may influence significantly the final craniofacial fracture pattern and this may be detrimental for some motorcyclists wearing full-face helmets. The positive correlation of full-face helmet wearing with fatal middle cranial fossa

fractures and ponto-medullary injuries, in the absence of facial fractures, raised questions about the efficacy of rigid face-bars. Conversely, the lack of significant neurotrauma in cases suffering facial fractures provides support for the beneficial energy absorbing role of facial fracturing. It is therefore recommended that energy absorption properties be incorporated into the face-bar Of a full-face helmet to overcome the paradox of facial injury prevention at the expense of fatal skull base injury propagation.

REFERENCES

1. Lee KF, LK Wagner, YE Lee, JH Suh, SR Lee
The impact-absorbing effects of facial fractures in closed-head
injuries: An analysis of 210 patients.
J Neurosurg 1987; 66: 542-547

2. Le Fort R
Etude expérementale sur les fractures del la mâchoire
superieure.
Rev Chir de Paris 1901; 23: 208-227; 360-379; 479-507

3. Cairns H, H Holbourn
Head injuries in motorcyclists: With special reference to
crash -helmets.
Br Med J 1943; 1: 591-598

4. Dowdell B, GL Lon& J Ward, M Griffiths
A study of helmet damage and rider head/neck injuries for
crash involved motorcyclists.
Road Safety Bureau Crashlab Research Note 5/88 1988; 1-33

5. Pedder JB, SB Hagues, GM Mackay
A study of 93 fatal two-wheeled motor vehicle accidents.
IRCOBI 1979; 24-38

6. Carr WP, D Brandt, K Swanson
Injury patterns and helmet effectiveness among hospitalized
motorgyclists.
Minn Med 1981; Sept- 521-527

7. Harms FL
A study of motorcyclist casualties with particular reference to
head injuries.
IRCOBI 1984; 91-97

8. Björnstig UL, PO Bylund, T Lekander, B Brorsson
Motorcycle fatalities in Sweden.
Acta Chir Scand 1985; 151: 577-581

9.Krantz KPG
Head and neck injuries to motorcycle and moped riders -
with special regard to the effect of protective helmets.
Injury 1985; 16: 253-258

10.Cooter RD, DJ David
Computer-based coding of fractures in the craniofacial region
Br J Plast Surg 1989; 42: 17-26

11.Cooter RD
Computed tomography in the assessment of protective
helmet deformation.
J Trauma 1990; 30: 55-68

12.Cooter RD, DJ David, AJ McLean, DA Simpson
Helmet-induced skull base fracture in a motorcyclist
Lancet 1988; 1: 84-85

13.Simpson DA, PC Blumbergs, RD Cooter, M Kilminster,
AJ McLean, G Scott
Pontomedullary tears and other Voss brain stem injuries
after vehicular accidents.
J Trauma 1989; 29: 1519-1525

14.Wood-Jones F
The ideal lesion produced by judicial hanging
Lancet1913; Jan 4. 53

So everyone who wears a helmet should stop? Race car drivers, football players, downhill skiers, constructions workers, HD bike testers. Sorry, I dont buy that crap. I know better.

 My mother rides with a cruiser group. She is the only one who wears a helmet despite the others messing with her about it. So far this year two of the group are dead from minor head impacts.

Very interesting study.  I hope this leads to better made helmets.  For now I'll still wear my full face and try not to land on my face.

  Maggie

Good article.  Thanks for taking the time to share it with us.  I have had two good friends go down this past year pretty bad.  Neither of them would be alive if they hadn't had their helmets on.  One of them hit a light pole head on with her helmet.  She only suffered a mild concussion and some bruising on her face.  Thats it. 

 I've always worn my helmet since I first started riding several years back.  I will put my helmet on, even for a quick trip to the store. It's not worth the risk.  I know many more riders who are here today because of a helmet. 

  Most of the people who complain about them being too hot or too heavy, haven't tried on the right helmet.  Helmet technology has came along ways over the years.  I have an HJC AC-12 carbon fiber helmet.  The ventilation in it is awseome.  It feels like I have two ac vents blowing on me when i'm riding. 

I understand everyone wanting to have the right to choose to wear a helmet or not.  However to me, it's kind of like wearing a seatbelt.  Most people don't argue with the fact that most states require you to wear a seatbelt.  Most everyone knows that wearing a seatbelt can be the difference between life and death or serious injury in a car accident.  Whats the difference between wearing a seatbelt and wearing a helmet?  Both can and will save your life.  Why do people wear a seatbelt without questioning it, but will question wearing a helmet?

It is therefore recommended that energy absorption properties be incorporated into the face-bar Of a full-face helmet to overcome the paradox of facial injury prevention at the expense of fatal skull base injury propagation.

Actually, what I find interesting is this - while I believe that nightbreed is using this article to advocate against the wearing of helmets, the doctors come to the conclusion that energy absorption properties need to be incorporated into the helmet, which makes more sense. I'm all about improving helmets to protect me better.

I also would tend to believe that since the newest data used to create this study is 1990, helmets have improved since then.

Abstract of a 1995 study on the same topic:

Johnson RM, McCarthy MC, Miller SF, Peoples JB.

Department of Surgery, Southern Illinois University, Springfield.

Helmets are effective in decreasing maxillofacial trauma in motorcycle crashes. The impact, however, of motorcycle crashes on the location and patterns of craniofacial injuries among helmeted versus unhelmeted patients has not been examined. In the present study, 331 injured motorcyclists were evaluated to compare the incidence of craniofacial and spinal injury in 77 (23%) helmeted and 254 (77%) nonhelmeted patients. Nonhelmeted motorcyclists were three times more likely to suffer facial fractures (5.2% vs. 16.1%) than those wearing helmets (p < 0.01). Skull fracture occurred in only one helmeted patient (1.2%), compared with 36 (12.3%) of nonhelmeted patients (p < or = 0.01). The incidence of spinal injury was not significantly different between the two groups. Blood alcohol levels demonstrated that 12% of the helmeted group were legally intoxicated (blood alcohol level > 100 mg/dL), in contrast to 37.9% of the nonhelmeted motorcyclists (p < or = 0.01). Failure to wear a helmet resulted in a significantly higher incidence of craniofacial injury among patients involved in motorcycle crashes, but did not affect spinal injury or mortality. Alcohol usage seemed to correlate with failure to use helmets. Helmet use should be legally mandated on a national level for all motorcyclists.

While I don't agree with the last statement in the abstract, I think the message between these two studies is clear: while helmets aren't a perfect solution, they are the best current solution to the problem.

Some head impacts simply aren't survivable. In a crash that severe, a helmet only alters the type of injury that causes death. This study is analogous to those that "prove" helmets break necks. In fact, the helmet prevented one kind of fatal injury only to re-route the forces involved to produce another kind of fatal injury.

By focusing on injuries severe enough to kill the victim, this study leaves out a far greater number of impacts in which injury is either reduced to make it survivable or prevented completely. A complete accounting of the costs and benefits of helmets must include all impacts.

Motorcyclist Magazine article: Motorcycle Helmet Performance: Blowing the Lid Off

http://www.motorcyclistonline.com/gearbox/motorcycle_helmet_review/

Can you cite a source for that?

Because a helmet decreases the peak deceleration of the skull as the foam absorbs impact energy, it would seem that the deceleration of the brain would necessarily be decreased as well. And even if brain injury isn't prevented, a helmet still provides valuable protection if injury severity is reduced.

When a person receives an impact to the head from an outside force, it can injure the skin, skull, and the brain. Skin covers the skull. Skin injuries can include cuts, burns, and bruising.

A person with skin injuries may or may not have a brain injury.
       
Conversely, persons with a traumatic brain injury may or may not have visible skin injuries on their head.
       
The skull is hard and composed of bone. The skull covers the brain.

The skull is hard and protects the soft brain inside it.

The inside of a skull is rough.

The inside of the skull can contribute to brain injury if an outside force causes the brain to move from its normal position and rub across the rough skull.            

Coup-Contrecoup Injury describes contusions that are both at the site of the impact and on the complete opposite side of the brain.
       
This occurs when the force impacting the head is not only great enough to cause a contusion at the site of impact, but also is able to move the brain and cause it to slam into the opposite side of the skull, which causes the additional contusion.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

When a person receives an impact to the head from an outside force, but the skull does not fracture or displace this condition is termed a "closed head injury". Again, separate terminology is added to describe the brain injury. For example, a person may have a closed head injury with a severe traumatic brain injury.      
With a closed head injury, when the brain swells, the brain has no place to expand. This can cause an increase in intracranial pressure (the pressure within the skull).
             
If the brain swells and has no place to expand, this can cause brain tissues to compress, causing further injury.
       
As the brain swells, it may expand through any available opening in the skull, including the eye sockets. When the brain expands through the eye sockets, it can compress and impair the functions of the eye nerves. For instance, if an eye nerve, Cranial Nerve III, is compressed, a person's pupil (the dark center part of the eye) will appear dilated (big). This is one reason why medical personal may monitor a person's pupil size and intracranial pressure.

             

             
This diagram shows a neuron functioning normally with the electrical impulses flowing from one neuron through the axon and onto the dendrites of the next neuron.

When the head moves, the brain also moves. The different layers of the brain move at different times because each layer has a different density. The illustration shows this movement and how it can result in stress and strain being placed on the neurons and the axons that run though the brain. The axons can end up being stretched, sheared, twisted, or compressed. The next four sketches show a detailed view of what happens to an axon when it is stretched, sheared, twisted, and compressed.

               
             
The flow of ions and fluid into the axon causes it to swell, which in turn leads to the destruction of the neurolema.

             
             

If your car is rear-ended, the movements and forces are reversed. The brain first impacts the front of the skull instead of the rear of the skull. The illustrations shows what can happen if your car is rear-ended or if you take a direct blow to the face.

As the head accelerates rapidly backward, the brain lags behind the skull, and the front of the brain strikes the front of the skull. An area of extremely low pressure develops in the space between the brain and the rear of the skull. Bubbles form inside the oxygen-laden blood in the microvascular system that supplies the back of the brain. The brain, which initially had struck the front of the skull, starts moving backward. The low pressure area that had been created in the space between the brain and the rear of the skull is suddenly changed into a high pressure area. This causes the bubbles to collapse. The sudden growth and collapse of these vapor bubbles puts tremendous pressure on the microscopic blood vessels in the brain. Often these blood vessels are badly damaged. Areas of the brain fed by these vessels are suddenly deprived of oxygen, and death to the brain cells in the rear of the brain occurs.

An                epidural hematoma forms between the skull and the dura mater, the tough outer membrane that covers the brain. Epidural hematomas are most commonly seen in conjunction with a skull fracture. If the hematoma is not removed it can cause brain damage by putting pressure on the brain.

A                subdural hematoma forms between the dura mater and the underlying membranes that cover the brain. These hematomas are seen most often in association with direct damage to the brain. Symptoms from hematomas may appear immediately or gradually as blood seeps out of torn blood vessels.

             
              Intracerebral hematomas result from accumulation of blood within                the brain caused by bleeding in and around the brain.

Squid Killer:

So everyone who wears a helmet should stop? Race car drivers, football players, downhill skiers, constructions workers, HD bike testers. Sorry, I dont buy that crap. I know better.

Where on any of my posts have I told someone not to wear a helmet? If a motorcyclist feels safer riding with a helmet, then by all means they should ride with a helmet. Peer pressure or vanity should not influence the decision. Feeling safe on a motorcycle is one of the first steps to riding safer.

I presented the informational study because there are those of us who advocate freedom of choice that aren't (in your words) clueless about the pros and cons of motorcycle helmets. My position within a SMRO requires that I digest all information available on the helmet debate.