Documentation:FIB book/Head Injuries in Skateboarding

Introduction

With a growing population of 10 million skateboarders in the United States alone, there are approximately 66,000 skateboard related injuries reported each year. This increase in participation has led to higher rates of head injuries resulting from skateboarding. Recent studies have shown that injuries to the head make up 75% of all hospital admitted skateboarding related injuries Because of its high speeds and inherent danger in many of the maneuvers performed by skateboarders, the understanding of the biomechanics behind these injuries is an important step in increasing overall participant safety.

Background

Reported skateboard related head injuries include skull fractures, concussion and intracranial hemorrhage. Studies have shown that skateboarders who suffer a head injury will likely have multiple diagnoses from the single injury event, with an average of 2.4 diagnoses per patient. In addition to this, patients who suffered a skull fracture are 19 times more likely to be diagnosed with intracranial hemorrhage.

Traumatic brain injury (TBI) resulting from a blow to the head is a frequent cause of head injuries that range from milder concussion to diffuse axonal injuries. In addition to the blunt force of the impact, the associated rotational accelerations in the event have been widely studied to cause these mild to severe TBI. Many of these more severe cases occur as a result of the skateboarder losing control of their board, thus making it more difficult for the person to use injury avoidance maneuvers commonly taught in the sport, such as attempting to roll on their back to spread out impact force.

Illustration of a contrecoup brain injury

Loss of control injuries can result in impacts to the occipital region of the skull, which in turn can cause contrecoup brain injury. Contrecoup brain injuries describe traumatic brain lesions that are located opposite the impact site, as a result of high forces sustained on impact. A contrecoup brain injury resulting in frontal lobe damage could present itself with long term impacts including paralysis, behavioral changes and trouble with speech or language.

Previous Work

In 1965, the study on the hazards associated with skateboarding started.  Until 2010, in almost all past reports, information on head trauma was not deeply researched and clinical details were missing. The percentage of head injuries from total injuries by skateboarding in the past reports was from 3-67%, with many reporting from 3-10%. The head injuries identified in these earlier reports were most often of the soft tissue variety. Four accounts reported head injuries of 25-67% but findings on the nature, extent, and outcomes from these injuries are generally incomplete.

Most of the papers related to skateboarding injuries were covering the epidemiology of injuries. Some reports covered types of injuries during skateboarding. In 2012, there was a study about experimental biomechanical study of head injuries in lateral falls with skateboard helmet. Kumar and his team especially focused on traumatic brain injuries (TBI) because there was limited research effort to the study of biomechanics of TBI in side impact conditions with the skateboard helmet. Also, in 2014, there was an article covering boarding injuries related to longboarding because of the increasing population enjoying longboarding compared to standard skateboarding. Some studies approach it with an etiological perspective. Benjamin used the last 10 years of the national hospital database to figure out the anatomic distribution of head and facial fractures.

Recently, there was an article focused on one of the most dangerous fundamental skills called the Ollie movement. Xinyao measured the inertia and the force during the movement with IMU sensors. Also, there is a study about managing head injury risks by using a helmet. McIntosh reviewed head injury risks and preliminary biomechanical data from skateboarding events. Also, McIntosh and Patton checked the standards for skateboard style helmets with testing impacting performance of commonly used helmets in skateboarding.

Problems and Controversies

A significant problem that defined the research done was the lack of consistency in the data. For example, the articles that Tominaga and his team wrote "Head injuries in hospital-admitted adolescents and adults with skateboard-related trauma" and " Epidemiological and clinical features of an older high-risk population of skateboarders" even though were analytical regarding the type and the severity of injury their sampling size was not sufficient for making an epidemiological case surrounding skateboard accidents. It should be mentioned that the data for the second paper were collected from Level II trauma Center and National Trauma Data Bank, for the first one only Level II trauma Center was used. By comparing the sample size of these two cases with the data retrieved from other articles such as Glenn Keays and Alex Dumas "Longboard and skateboard injuries" where over 4000 cases, in 4 years time, were examined it can be deduced that the samples used Tominaga's papers are not sufficient thus the derived results must be questioned. More specifically in "Epidemiological and clinical features of an older high-risk population of skateboarders" where both pre-mentioned databases were used, a sample size of 83 people was retrieved from Level II Trauma Bank, while 349 cases were taken into consideration from National Trauma Data Bank, it must be mentioned that these data were collected for 6 consecutive years (2000-2006). Even though the sample size of the latter database is much greater than the first one, it still lacks in comparison to the thousands cases of skateboard injuries that occur yearly, thus it was concluded that it was impossible to observe a specific injury pattern or tendencies by using these data.

On the other hand the articles that provided vast volume of samples such as "Longboard and skateboard injuries" and "Boarding Injuries: The Long and the Short of It" were proven to be great sources of information regarding the injury profiles of skateboarders, but unfortunately they failed to provide a severity profile for each region . These two articles were used in order to understand the chances of injury depending on the body region. Even though these articles were characterized by their great sampling size they only focused on the injury statistics without taking injury severity into consideration. All these differences and research deviations from article to article had a great impact in this epidemiological study.

Additionally, it must be noted that most of the statistical data that were presented in the articles mentioned before involved 20 year old studies. Thus, translating those samples into today's standards, by generalizing behavioral patterns and unshifted characteristics of skateboarders, was a big gamble. Is it safe to assume that the skateboarding community is unchanged? Do less people use skateboards nowadays due to Covid-19? Finally it should be mentioned that "Skateboard-Related Injuries: Not to be Taken Lightly. A National Trauma Databank Analysis" had a very important role in this epidemiological study. Since the authors were able to examine 2270 cases of injured skateboarders within a 5 year period, including all ages, types of injuries and their severity, solid results can be extracted and a solidified discussion could be made regarding injury tendencies and severity patterns.

Future Research

While reviewing the research work of risk of injury in skateboarding there was prominent issue of shortage of head injury specific data, among the head injury data too less usage of safety helmets was observed. Since currently no specific guideline is present on design and safety standards for skateboarding helmets, any helmet used for various wheeled recreational device activities is used for skate boarding. Peak linear acceleration (PLA) values were tested for different types of helmets and difference in values became prominent as the direction of impact was changed. Skateboarding can have impacts across different head sections, leading to different types of head injuries and further research has shown that age also plays a vital role in the anatomic division of injuries, injury severity and outcomes . Some numerical modelling and experimental studies at different impacts have been done to understand dynamics and stability for the movement of the skateboard but the studies did not provide the injury severity data, further studies need to be done to understand head kinematics, type of injury and their severity during different falls. Combination of mathematical and experimental analysis on different skateboarding impacts encompassing parameters such as velocity, angle, age, and weight of impact will be helpful in developing computational models for simulating head injury and further developing a customized standard for skateboarding helmet instead of having a one fit for all or a common standard for helmets across different sports.