Motocross-associated head and spine injuries in adult patients evaluated in an emergency department

Accepted Manuscript Motocross-associated head and spine injuries in adult patients evaluated in an emergency department

Lucas Oliveira J. e Silva, M. Fernanda Bellolio, Elisa M. Smith, David J. Daniels, Christine M. Lohse, Ronna L. Campbell PII: DOI: Reference:

S0735-6757(17)30324-8 doi: 10.1016/j.ajem.2017.04.058 YAJEM 56653

To appear in: Received date: Revised date: Accepted date:

13 March 2017 25 April 2017 26 April 2017

Please cite this article as: Lucas Oliveira J. e Silva, M. Fernanda Bellolio, Elisa M. Smith, David J. Daniels, Christine M. Lohse, Ronna L. Campbell , Motocross-associated head and spine injuries in adult patients evaluated in an emergency department. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Yajem(2017), doi: 10.1016/j.ajem.2017.04.058

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[Category: Original Contribution] AJEM15361 Motocross-Associated Head and Spine Injuries in Adult Patients Evaluated in an Emergency Department

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Lucas Oliveira J. e Silva

Christine M. Lohse, MS

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David J. Daniels, MD, PhD

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Elisa M. Smith, MD

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M. Fernanda Bellolio, MD, MS

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Ronna L. Campbell, MD, PhD

Author Affiliations: Department of Emergency Medicine (Mr Silva and Drs

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Bellolio, Smith, and Campbell), Department of Neurologic Surgery (Dr Daniels), and Division of Biomedical Statistics and Informatics (Ms Lohse),

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Mayo Clinic, Rochester, Minnesota. Mr Silva is a medical student,

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Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Brazil. Reprints: Ronna L. Campbell, MD, PhD, Department of Emergency

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Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905 ([email protected]). Funding: This research did not receive any specific grant from

funding agencies in the public, commercial, or not-for-profit sectors. Conflict of interest: None. Text word count: 2,906 Abstract word count: 242 No. of tables: 1

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No. of figures: 1 Running title: Motocross-Associated Head and Spine Injuries Publisher: To expedite proof approval, send proof via email to [email protected].

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©2017 Mayo Foundation for Medical Education and Research

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Abstract Background: Motor vehicle−related injuries (including off-road) are the leading cause of traumatic brain injury (TBI) and acute traumatic spinal cord injury in the United States.

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Objectives: To describe motocross-related head and spine injuries of adult

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patients presenting to an academic emergency department (ED).

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Methods: We performed an observational cohort study of adult ED patients evaluated for motocross-related injuries from 2010 through 2015. Electronic

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health records were reviewed and data extracted using a standardized review process.

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Results: A total of 145 motocross-related ED visits (143 unique patients)

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were included. Overall, 95.2% of patients were men with a median age of 25 years. Sixty-seven visits (46.2%) were associated with head or spine injuries.

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Forty-three visits (29.7%) were associated with head injuries, and 46 (31.7%) were associated with spine injuries. Among the 43 head injuries, 36

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(83.7%) were concussions. Seven visits (16.3%) were associated with at

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least 1 head abnormality identified by computed tomography, including skull fracture (n=2), subdural hematoma (n=1), subarachnoid hemorrhage

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(n=4), intraparenchymal hemorrhage (n=3), and diffuse axonal injury (n=3). Among the 46 spine injuries, 32 (69.6%) were acute spinal fractures. Seven patients (4.9%) had clinically significant and persistent neurologic injuries. One patient (0.7%) died, and 3 patients had severe TBIs. Conclusion: Adult patients evaluated in the ED after motocross trauma had high rates of head and spine injuries with considerable morbidity and mortality. Almost half had head or spine injuries (or both), with permanent impairment for nearly 5% and death for 0.7%.

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Keywords: motocross; motorcycle; sports injury; trauma; traumatic brain

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injury; traumatic spinal cord injury

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Abbreviations CT, computed tomography ED, emergency department EHR, electronic health record

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IQR, interquartile range

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REDCap, research electronic data capture

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LOC, loss of consciousness

Epidemiology TBI, traumatic brain injury

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TSCI, traumatic spinal cord injury

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STROBE, Strengthening the Reporting of Observational studies in

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Introduction Motocross is a nationally organized sport that is usually set outdoors on a course that combines natural terrain with human-made obstacles (1). Few studies have described injuries associated with motocross

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participation in adults (2,3), and to date, motocross-related head and spine

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injuries have been specifically described only in pediatric patients (4,5).

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Athletes participating in high-impact sports are at risk of traumatic brain injury (TBI) and traumatic spinal cord injury (TSCI) that can result in

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marked disabilities and major socioeconomic burdens. In the United States, on- and off-road motor vehicle collisions are the leading cause of TBI (6)

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and TSCI (7). More than 90% of patients evaluated for TBI in the

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emergency department (ED) have mild TBI (eg, concussion) (8). It is estimated that as many as 3.8 million concussions occur per year during

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competitive sports and recreational activities in the United States, even though a considerable number of cases likely are unreported (9). Although

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the consequences of TBI vary with the severity of the injury, growing

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literature suggests that even mild TBI can cause significant long-term sequelae, and the threshold for a safe vs unsafe level of head trauma remains

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unknown (10).

The number of injuries associated with high-impact sports,

including motocross, has increased with increasing participation (11,12), and to our knowledge, no studies to date have specifically characterized head and spine injuries in adult patients after motocross trauma. The purpose of this study was to characterize motocross-related head and spine injuries in adult patients who presented to the ED. We further aimed to provide insights

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on rates of these injuries in the setting of advanced protective gear and contemporary motorcycles. Methods Study Design and Population

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After drafting the protocol and receiving approval from the

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Institutional Review Board, we performed an observational cohort study. All

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adult patients (age, ≥18 years) evaluated for motocross related injuries in the ED of [our hospital; city, state] from January 1, 2010, through December 31,

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2015, were identified. The ED at our tertiary care academic institution has a volume of approximately 73,000 annual patient visits. Patients were

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identified by searching the trauma registry (TraumaBase, v9; CDM) for all

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patients with a traumatic injury due to a motocross trauma. Trauma data are prospectively collected and meet criteria for the National Trauma Registry

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Database (13). In addition, to identify patients who may not have been included in the trauma database, the electronic health record (EHR)

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(PulseCheck, v5.4; Optum) was queried using an electronic tracking system

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that included natural language processing; search terms for ED diagnoses were “motocross,” “motorcross,” “motorbike,” and “dirt bike.” Patients with

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injuries that occurred while using a motorized bike outside of a motocross track were excluded. All patients evaluated at our institution were asked for permission to use their medical records for research, and those who declined were excluded from the study. Patient data from ED admission through hospital discharge were reviewed, as were the outpatient follow-up records, when available.

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Data Collection and Main Variables The current study adheres to the STROBE (Strengthening the Reporting of Observational studies in Epidemiology) guidelines for reporting observational studies (14). After all subjects were identified, data

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were abstracted from the trauma registry and EHR through a standardized

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chart review process. To ensure data accuracy, data from a sample of 23

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visits (15.9%) were extracted in duplicate to identify variables prone to misinterpretation. The overall concordance for the initial double extraction

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was 88%. All discrepancies were discussed, and specific instructions for data abstraction and coding were revised to ensure consistent and accurate

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abstraction. Throughout the abstraction process, all questions were discussed

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with the principle investigator (withheld), and additional abstraction instructions were developed as needed. Patients with ambiguous imaging

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reports were discussed with a neurosurgeon (withheld). Reviewers met frequently to discuss doubtful reports and to review all coding rules and

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abstraction guidelines.

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The following variables were collected from the EHRs: 1) demographic variables (age, sex); 2) injury-associated variables (practice or

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competition setting, use of protective equipment; 3) imaging studies performed on the head and spine; 4) types of head and spine injuries; 5) signs and symptoms of neurologic injuries (loss of consciousness [LOC], transient or persistent numbness or tingling, transient or persistent weakness, persistent cognitive deficit, any other persistent neurologic deficit); 6) Glasgow coma scale at the scene and at the ED; 7) ED disposition; 8) surgical interventions (spinal and cranial surgery, any other procedure involving the head or spine); and 9) hospital length of stay. Neurologic signs

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or symptoms were considered persistent if they were present at the time of hospital discharge. Study data were recorded through a standardized abstraction form and managed using REDCap (Research Electronic Data Capture) tools hosted on an institutional data server. REDCap is a secure

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web-based application designed to support data capture for research studies

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(15).

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Head injuries and TBI were defined as head impact noted in the EHR or based on mechanism, including any of the following: concussion,

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skull fracture, or any intracranial injury identified by head CT (epidural and subdural hematoma, subarachnoid hemorrhage, intraparenchymal

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hemorrhage, diffuse axonal injury). Concussion was assumed for patients

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with a trauma-induced alteration in mental status, in the absence of any intracranial imaging abnormalities, and for patients with early symptoms

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such as headache, dizziness, nausea, vomiting, or lack of awareness of surroundings after head impact (9,16,17). Superficial head injuries (eg,

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lacerations), isolated nasal fracture, and facial or forehead abrasions were

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not included as head injuries. Spine injuries were defined as any acute injury related to the spine

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after the trauma, including all those based on spine CT (acute spinal fractures, epidural hematoma, acute disc herniation, ligamentous injury) and those based on signs and symptoms of cervical strain or thoracolumbar strain. All patients with back or cervical pain, without injuries detected in the imaging evaluation, were defined as having thoracolumbar strain and cervical strain, respectively. All preexisting spine injuries were excluded.

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Statistical Analysis Descriptive statistics are reported. Continuous features are summarized as median and interquartile range (IQR). Categorical features are summarized as frequency counts and percentages based on number of

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ED visits (N=145).

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Results

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Of 165 motocross injury−related ED visits, 145 visits, representing 143 unique patients, met study inclusion criteria and were

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included in our cohort (Figure). Of the 145 visits, 138 (95.2%) were from men. The median age was 25 years (IQR, 21-38 years). Sixty-seven ED

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visits (46.2%) from 66 unique patients were associated with head or spine

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injuries. Overall, 43 ED visits (29.7%) were associated with head injuries, 46 (31.7%) with spine injuries, and 22 (15.2%) with both head and spine

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injuries. Of the 67 visits with head or spine injuries, 62 patients (92.5%) were wearing a helmet at the time of injury; information regarding the use of

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chest protectors or cervical stabilization equipment at the time of the injury

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typically was not recorded. Imaging Studies

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Eighty-three visits (57.2%) included head CT in the evaluation,

and 106 (73.1%) had at least 1 CT of the spine (cervical, thoracic, or lumbar imaging). CT of the head was performed for 41/43 patients (95.3%) with head injuries and 42/102 (41.2%) without. At least 1 CT of the spine was performed for all 46 patients (100%) with spine injuries and 60/99 (60.6%) without. All imaging evaluations occurred during the hospital stay, with most performed during the ED evaluation.

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Head Injuries Among the 43 ED visits associated with head injury, 36 (83.7%) were concussions, of which 27 (75.0%) occurred with LOC. Seven visits (16.3%) were associated with 1 or more abnormalities identified by head CT

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imaging, including skull fracture (n=2), subdural hematoma (n=1),

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subarachnoid hemorrhage (n=4), intraparenchymal hemorrhage (n=3), and

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diffuse axonal injury (n=3). Patients with head injuries were most frequently admitted to the general surgical floor (n=18 [41.9%]) and the intensive care

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unit (n=12 [27.9%]). Spine Injuries

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Forty-six ED visits were associated with spine injuries, including

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32 acute spinal fractures (69.6%; transverse process fractures, n=16; vertebral compression or burst, n=16; and other types of vertebral fractures,

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n=17). Four patients (8.7%) had an epidural hematoma. Ten patients (21.7%) had a thoracolumbar strain and 3 (6.5%) had a cervical strain.

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Twelve patients (26.1%) with spine injuries were admitted to the intensive

ED.

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care unit, and 11 (23.9%) were taken to the operating room directly from the

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Head and Spine Interventions Ten patients (6.9%) underwent a procedural or surgical

intervention involving the head or spine. Three patients (2.1%) underwent specific interventions for the head (all had intracranial pressure monitoring). Seven patients (4.8%) underwent specific interventions for the spine (spinal fusion, n=5; placement of an extension cast, n=2).

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Functional Outcomes One patient (0.7%) died after a C1 Jefferson fracture and anoxic brain injury. Seven patients (4.8%) had persistent neurologic deficits at hospital discharge. Among the patients with persistent neurologic deficits, 2

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patients had paraplegia due to complete spinal cord injuries after 3 column

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fractures of the thoracic spine, and 2 patients had a severe TBI with

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cognitive deficits, including impaired memory, orientation, and comprehension. Another patient with severe TBI was in a persistent

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vegetative state and was discharged to a nursing facility. Two patients were discharged home with less severe injuries; one had persistent numbness

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consistent with an injury to the maxillary nerve division of the trigeminal

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nerve (due to an orbital fracture) and one had persistent mild right upperextremity weakness due to an acute C7 superior facet fracture. All patients

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with persistent neurologic deficits at discharge, as well as the patient who died, were wearing a helmet at the time of injury, but information about

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cervical stabilization was not specifically recorded. The Table summarizes

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patient characteristics, injuries, and outcomes. Discussion

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In this study of consecutive adult patients presenting to the ED

with motocross-related injuries over a 6-year period, we found that patients were primarily young men and that almost one-half (46.2%) of visits were associated with head or spine injuries. Approximately one-third of visits (29.7%) were associated with head injuries and one-third (31.7%) were associated with spine injuries. Seven patients (16.3%) had at least one abnormal head CT finding. Among patients with spine injuries, most had acute spinal fractures (69.6%), and among those with head injuries, most had

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concussions (83.7%). One patient (0.7%) died and 7 patients (4.8%) had persistent neurologic deficits at the time of hospital discharge. Current data specifically regarding motocross participation in the United States are not available. The last report from the National Survey on

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Recreation and the Environment of off-highway vehicle recreation

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(including off-road motorcycles) estimated that an average of 18.6% of the

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population annually participated in off-highway vehicle recreational driving between late 1999 and 2007 (18). Motocross has one of the highest

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incidence rates for injuries compared with other high-impact sports (3); the average yearly percentage of injuries is around 10%, whereas in bicycling,

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car racing, motorboat, downhill ski, and equestrian sports, it is less than 2%.

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Data from the National Electronic Injury Surveillance System of the Consumer Product Safety Commission (2000-2011) showed that across 7

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extreme sports, motocross had the highest incidence of neck fractures and accounted for 27.67% of all reported neck fractures, but when compared

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with snowboarding, snow skiing, and skateboarding, motocross was

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associated with fewer concussions (11). The number of injuries associated with motocross has increased (11,12) with increasing participation.

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The majority (95%) of patients in our study were young men; this

finding was consistent with those of an observational study from Southern California (2) and a 12-year descriptive study (3). According to our findings and previous studies, adult patients with motocross-related injuries seem to be primarily in their early twenties. In a study of children and adults, Gorski et al (2) found similar injury rates after motocross trauma, with 33% of patients having head injuries and more than 80% having a concussion, despite all wearing a

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helmet at the time of injury. A large European study of professional athletes participating in off-road competition over 12 years reported a head trauma rate of 5.7%; however, head injury was not clearly defined in that report, and an update in current guidelines and definitions of concussion and TBI might

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have resulted in underdiagnosis (3). Our relatively higher rates of head

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injuries may be due to our inclusion criteria, which were restricted to injuries

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that occurred in a motocross track and in patients who presented to a tertiary hospital ED.

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Among those patients with head injuries, we observed a high rate of concussion (83.7%), with most associated with LOC. Our findings are

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similar to a study of pediatric patients with motocross injuries, which was

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performed in the same geographic region and also had high rates of head injuries, even with most patients wearing a helmet at the time of injury (4).

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More than 90% of those head injuries were concussions, and almost all children had LOC. Together, these findings suggest more severe injuries and

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potentially worse long-term outcomes in patients with motocross-related

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head injuries because sports-related concussions generally occur without LOC (17). LOC in patients with concussion has been associated with early

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cognitive deficits, but long-term implications remain unknown (17,19,20). The real incidence of mild TBI associated with motocross is likely higher than that reported here because most patients do not pursue medical care after minor injuries. Luo et al (5) reported that more than 60% of young motocross riders who reported concussion symptoms continued riding on the same day. In a North American observational study of motocross injuries conducted from 2000 through 2001 (2), 14% of patients had spine injuries,

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with 65% of these injuries being acute spinal fractures. Our higher rate of spine injuries could be due to the high rate of CT imaging in our cohort (70% had at least one CT of the spine) and possible variation in definitions across studies (we included sprains of the spine in our definition).

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A large Cochrane systematic review of on-road traumatic injuries

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reported a 42% decreased incidence of death and 69% decreased incidence

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of head injury with motorcycle helmet use (21). Our high rates of head injuries in the setting of high helmet usage highlight the dangers of

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motocross riding. Even though our state does not require helmets for offroad riders older than 18 years (22), helmet usage is possibly the reason why

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patients did not have worse injuries.

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Emergency providers need to be aware of the high rates of head and spine injuries in this population, despite the use of protective equipment,

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to facilitate early recognition and management of these patients. It is important to determine whether patients have an improvement or

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deterioration in neurologic status since the time of injury and determine the

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need for emergent neuroimaging to exclude severe injuries (17). The high usage of head and spine CT during the ED evaluation could represent a good

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level of awareness by emergency providers that was complemented by our strict protocols as a level 1 trauma center. Head CT should not be deferred when an intracranial injury is suspected (17). Motocross-related injuries in adult and pediatric patients frequently require hospital admission and surgical procedures. Nearly half of pediatric patients treated at a level 1 trauma center required hospitalization and one-third required surgery (23), whereas in our study, nearly 80% required hospitalization and one-quarter were directly transferred to the

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operating room from the ED. The National Electronic Injury System−All Injury Program data from 2001-2004 showed that for patients younger than 20 years, injuries in motocross areas (compared with other off-road areas) were more severe and patients were more likely to be hospitalized (14.9% vs

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5.6%) (24). Motocross areas were defined as a motocross park, race track,

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motorcycle park, or unspecified off-road location if the activity involved

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racing or jumping with motorcycles; off-road areas were defined as woods, field, trail, backyard of home, and other specific off-road locations. The

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long-term functional and economic burden caused by these injuries in young males would be expected to be even greater in the setting of persistent

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neurologic injury, which affected almost 5% of our cohort. These injuries

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are potentially fatal, and the mortality rate was 1% in a mixed population of adults and children (2), similar to our mortality rate of 0.7%.

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Limitations

This study has several limitations. We conducted a retrospective

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observational (descriptive) study using data extracted from EHRs. No

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comparison cohort was used. Data were not captured for research purposes and thus are only as accurate as the record itself. Use of safety equipment

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(eg, chest and neck protector) and the setting of the injury (competition vs practice) were poorly documented in the EHRs, which precluded our ability to draw any conclusions about their impact on safety. Another limitation includes our method of patient sampling. Our study may have missed patients with minor injuries who thus did not have a diagnosis of a motocross-related injury in the ED, did not meet criteria for trauma team activation, or did not get admitted to a trauma service.

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Our findings are the result of an observational study of patients presenting to an academic ED, level 1 trauma center, and tertiary (referral) hospital; as such, these findings may not be generalizable to other clinical settings.

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Conclusion

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Adult patients evaluated in the ED after motocross trauma had

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high rates of head and spine injuries and marked levels of morbidity and mortality. An increased awareness of the dangers associated with motocross

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and increased development of safer equipment are needed. Prospective research that identifies characteristics specifically predictive of these injuries

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might help focus on a target population and facilitate development of new

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state or national policies to decrease the considerable morbidity and

Disclosures

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None.

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mortality resultant from these injuries.

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References 1. Grange JT, Bodnar JA, Corbett SW. Motocross medicine. Curr Sports Med Rep. 2009 May-Jun;8(3):125-30. 2. Gorski TF, Gorski YC, McLeod G, Suh D, Cordero R, Essien F, et al.

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Patterns of injury and outcomes associated with motocross accidents.

IP

Am Surg. 2003 Oct;69(10):895-8.

CR

3. Gobbi A, Tuy B, Panuncialman I. The incidence of motocross injuries: a 12-year investigation. Knee Surg Sports Traumatol

US

Arthrosc. 2004 Nov;12(6):574-80.

4. Reference withheld for anonymous review.

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5. Luo TD, Clarke MJ, Zimmerman AK, Quinn M, Daniels DJ,

M

McIntosh AL. Concussion symptoms in youth motocross riders: a prospective, observational study. J Neurosurg Pediatr. 2015

ED

Mar;15(3):255-60.

6. Centers for Disease Control and Prevention. Traumatic brain injury in

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the United States: emergency department visits, hospitalizations and

CE

deaths 2002-2006 (Blue Book). [Internet]. c2006. [cited 2017 Feb 13]. Available from:

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https://www.cdc.gov/traumaticbraininjury/tbi_ed.html/;%202006 7. Devivo MJ. Epidemiology of traumatic spinal cord injury: trends and future implications. Spinal Cord. 2012 May;50(5):365-72.

8. Korley FK, Kelen GD, Jones CM, Diaz-Arrastia R. Emergency department evaluation of traumatic brain injury in the United States, 2009-2010. J Head Trauma Rehabil. 2016 Nov/Dec;31(6):379-387. 9. Harmon KG, Drezner JA, Gammons M, Guskiewicz KM, Halstead M, Herring SA, et al. American Medical Society for Sports Medicine

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position statement: concussion in sport. Br J Sports Med. 2013 Jan;47(1):15-26. Erratum in: Br J Sports Med. 2013 Feb;47(3):184. 10. Young JS, Hobbs JG, Bailes JE. The impact of traumatic brain injury on the aging brain. Curr Psychiatry Rep. 2016 Sep;18(9):81.

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11. Sharma VK, Rango J, Connaughton AJ, Lombardo DJ, Sabesan VJ.

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The current state of head and neck injuries in extreme sports. Orthop J

CR

Sports Med. 2015 Jan 8;3(1):2325967114564358.

12. Singh R, Theobald P, Hamad AK, Hay S. Motocross biking for

US

competition and for recreation: a prospective analysis of 423 injured riders. BMJ Open Sport Exerc Med. 2015 Oct 14;1(1):e000019.

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13. National Trauma Databank. National trauma data standard: data

M

dictionary: 2017 admissions [Internet]. 2016 Jul 12 [cited 2017 Mar 9]; [214 p.]. Available from:

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http://www.ntdsdictionary.org/documents/NTDSDataDictionary2017Admissions.pdf

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14. Vandenbroucke JP, von Elm E, Altman DG, Gotzsche PC, Mulrow

CE

CD, Pocock SJ, et al; STROBE Initiative. STrengthening the Reporting of Observational studies in Epidemiology (STROBE):

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explanation and elaboration. Int J Surg. 2014 Dec;12(12):1500-24. 15. Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap): a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009 Apr;42(2):37781. 16. Kelly JP, Rosenberg JH. Diagnosis and management of concussion in sports. Neurology. 1997 Mar;48(3):575-80.

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17. McCrory P, Meeuwisse WH, Aubry M, Cantu RC, Dvorak J, Echemendia RJ, et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport, Zurich, November 2012. J Athl Train. 2013 Jul-Aug;48(4):554-75.

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18. Cordell Hk, Betz CJ, Green G, Stephens B. Off-highway vehicle

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recreation in the United States and its regions and states: a national

CR

report from the National Survey on Recreation and the Environment (NSRE). [Internet]. c2008. [cited 2017 Feb 13]. Available from:

US

http://archive.sharetrails.org/uploads/EconomicStudies/National%20S urvey%20on%20Rec%20&%20Env_NSRE_OHV_FINAL_FEBRUA

AN

RY_2008.pdf

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19. Leininger BE, Gramling SE, Farrell AD, Kreutzer JS, Peck EA 3rd. Neuropsychological deficits in symptomatic minor head injury

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patients after concussion and mild concussion. J Neurol Neurosurg Psychiatry. 1990 Apr;53(4):293-6.

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20. Lovell MR, Iverson GL, Collins MW, McKeag D, Maroon JC. Does

CE

loss of consciousness predict neuropsychological decrements after concussion? Clin J Sport Med. 1999 Oct;9(4):193-8.

AC

21. Liu BC, Ivers R, Norton R, Boufous S, Blows S, Lo SK. Helmets for preventing injury in motorcycle riders. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD004333.

22. Reference withheld for anonymous review. 23. Reference withheld for anonymous review. 24. Centers for Disease Control and Prevention (CDC). Nonfatal injuries from off-road motorcycle riding among children and teens: United

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States, 2001-2004. MMWR Morb Mortal Wkly Rep. 2006 Jun

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9;55(22):621-4.

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Legend Figure. Flowchart of Patient Enrollment. Emergency department (ED) diagnoses (cases in the trauma registry) included “motocross,” “motorcross,”

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“motorbike,” and “dirt bike.” Numbers indicate ED visits.

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Table. Emergency Department Visits—Baseline Characteristics and Outcomesa ED Visits Head Injuries

Spine Injuries

(N=145)

(n=43)

(n=46)

Age, y

25 (21-38)

27 (21-40)

25.5 (21-38.5)

Male sex

138 (95.2)

41 (95.3)

43 (93.5)

3 (7)

2 (4.35)

2 (4.7)

0 (0)

3 (2.1)

3 (7)

2 (4.35)

135 (94.4)

35 (81.3)

42 (91.3)

3 (2.1)

4-8

2 (1.4)

9-14

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3

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ED Glasgow coma scaleb

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Variable

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All

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15

…

33 (76.8)

…

Concussion

…

36 (83.7)

…

…

2 (4.7)

…

…

0 (0)

…

Subdural hematoma

…

1 (2.3)

…

Subarachnoid

…

4 (9.3)

…

…

3 (7)

…

…

3 (7)

…

Acute spinal fracture

…

…

32 (69.6)

Epidural hematoma

…

…

4 (8.7)

PT

Skull fracture

ED

Loss of consciousness

AC

Head injury (n=43)

CE

Epidural hematoma

hemorrhage

Intraparenchymal hemorrhage Diffuse axonal injury Spine injury (n=46)

ACCEPTED MANUSCRIPT

Acute disc herniation

…

…

1 (2.2)

Ligamentous injury

…

…

5 (10.9)

Cervical strain

…

…

3 (6.5)

Thoracolumbar strain

…

…

10 (21.7)

Head

83 (57.2)

41 (95.3)

36 (78.3)

Any spine

106 (73.1)

41 (95.3)

46 (100)

Cervical spine

105 (72.4)

40 (93)

46 (100)

Lumbar spine

85 (58.6)

33 (76.7)

41 (89.1)

Thoracic spine

61 (42.1)

32 (74.4)

42 (91.3)

7 (16.2)

4 (8.7)

53 (36.5)

18 (41.9)

19 (41.3)

21 (14.5)

12 (27.9)

12 (26)

31 (21.4)

6 (14)

11 (24)

10 (6.9)

5 (11.6)

8 (17.4)

7 (4.8)

5 (11.6)

4 (8.7)

AC

-24-

Hospital length of stay, d

2 (0-4)

2 (1-5)

3 (1-5)

In-hospital death

1 (0.7)

1 (2.3)

1 (2.2)

40 (27.6)

General surgical floor

PT

ED

Intensive care unitc

M

Home

Head or spine

IP

CR

US

AN

ED disposition

Operating room

T

CT imaging

CE

intervention or surgery Persistent neurologic deficit at hospital discharge

Abbreviations: CT, computed tomography; ED, emergency department. a

Data are summarized as number (%) or median (interquartile range).

b

Data not available for 2 patients.

c

Includes all types of intensive care units at our institution.

ACCEPTED MANUSCRIPT -25-

AC

CE

PT

ED

M

AN

US

CR

IP

T

Fig. 1