a b s t r a c t

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

Objectives: To describe motocross-related head and spine injuries of adult patients presenting to an academic emergency department (ED).

Methods: We performed an observational cohort study of adult ED patients evaluated for motocross-related in- juries from 2010 through 2015. electronic health records were reviewed and data extracted using a standardized Review process.

Results: A total of 145 motocross-related ED visits (143 unique patients) 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. 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 (83.7%) were concussions. Seven visits (16.3%) were associated with at least 1 head abnormality identified by computed tomography, including Skull fracture (n = 2), subdural hematoma (n = 1), subarachnoid hemorrhage (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 im- pairment for nearly 5% and death for 0.7%.

(C) 2017

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 par- ticipation in adults [2,3], and to date, motocross-related head and spine injuries have been specifically described only in pediatric patients [4,5].

Abbreviations: CT, computed tomography; ED, emergency department; EHR, electronic health record; IQR, interquartile range; LOC, loss of consciousness; REDCap, research electronic data capture; STROBE, Strengthening the Reporting of Observational studies in Epidemiology; TBI, traumatic brain injury; TSCI, traumatic spinal cord injury.

? Conflict of interest: None.

?? Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

* Corresponding author at: Department of Emergency Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905, United States.

E-mail address: [email protected] (R.L. Campbell).

¹ Mr. Silva is a medical student, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Brazil.

Athletes participating in high-impact sports are at risk of traumatic brain injury and traumatic spinal cord injury (TSCI) that can result in marked disabilities and major socioEconomic burdens. In the United States, on- and off-road Motor vehicle collisions are the leading cause of TBI [6] and TSCI [7]. More than 90% of patients evaluated for TBI in the emergency department (ED) have mild TBI (e.g., concussion) [8]. It is estimated that as many as 3.8 million concussions occur per year during competitive sports and recreational activities in the United States, even though a considerable number of cases likely are unreport- ed [9]. Although the consequences of TBI vary with the severity of the injury, growing literature suggests that even mild TBI can cause signifi- cant long-term sequelae, and the threshold for a safe vs unsafe level of head trauma remains unknown [10].

The number of injuries associated with high-impact sports, includ- ing 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

http://dx.doi.org/10.1016/j.ajem.2017.04.058 0735-6757/(C) 2017

spine injuries in adult patients who presented to the ED. We further aimed to provide insights on rates of these injuries in the setting of ad- vanced protective gear and contemporary motorcycles.

Methods

Study design and population

After drafting the protocol and receiving approval from the Mayo Clinic Institutional Review Board, we performed an observational cohort study. All adult patients (age, >=18 years) evaluated for motocross relat- ed injuries in the ED of Mayo Clinic Hospital, Saint Marys Campus (Rochester, Minnesota) from January 1, 2010, through December 31, 2015, were identified. The ED at our tertiary care academic institution has a volume of approximately 73,000 annual patient visits. Patients were identified by searching the trauma registry (TraumaBase, v9; CDM) for all patients with a traumatic injury due to motocross trauma. Trauma data are prospectively collected and meet criteria for the Na- tional Trauma Registry Database [13]. In addition, to identify patients who may not have been included in the trauma database, the electronic health record (PulseCheck, v5.4; Optum) was queried using an electronic Tracking system that included natural language processing; search terms for ED diagnoses were “motocross,” “motorcross,” “motor- bike,” and “dirt bike.” Patients with 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 med- ical 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.

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 were abstracted from the trauma registry and EHR through a stan- dardized chart review process. To ensure data accuracy, data from a sample of 23 visits (15.9%) were extracted in duplicate to identify vari- ables prone to misinterpretation. The overall concordance for the initial double extraction was 88%. All discrepancies were discussed, and specif- ic instructions for data abstraction and coding were revised to ensure consistent and accurate abstraction. Throughout the abstraction pro- cess, all questions were discussed with the principle investigator (R.L.C.), and additional abstraction instructions were developed as needed. Patients with ambiguous imaging reports were discussed with a neurosurgeon (D.J.D.). Reviewers met frequently to discuss doubtful reports and to review all coding rules and abstraction guidelines.

The following variables were collected from the EHRs: 1) demo- graphic variables (age, sex); 2) injury-associated variables (practice or 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 persis- tent weakness, persistent cognitive deficit, any other persistent neuro- logic 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 or symptoms were considered persistent if they were present at the time of hospital discharge. Study data were re- corded through a standardized abstraction form and managed using REDCap (Research Electronic Data Capture) tools hosted on an institu- tional data server. REDCap is a secure web-based application designed to support data capture for research studies [15].

Head injuries and TBI were defined as head impact noted in the EHR or based on mechanism, including any of the following: concussion, skull fracture, or any Intracranial injury identified by head CT (epidural and subdural hematoma, subarachnoid hemorrhage, intraparenchymal hemorrhage, diffuse axonal injury). Concussion was assumed for pa- tients with a trauma-induced alteration in mental status, in the absence of any intracranial imaging abnormalities, and for patients with early symptoms such as headache, dizziness, nausea, vomiting, or lack of awareness of surroundings after head impact [9,16,17]. Superficial head injuries (eg, lacerations), isolated nasal fracture, and facial or fore- head abrasions were not included as head injuries.

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

Statistical analysis

Descriptive statistics are reported. Continuous features are summa- rized as median and interquartile range (IQR). Categorical features are summarized as frequency counts and percentages based on number of ED visits (N = 145).

Results

Of 165 motocross injury-related ED visits, 145 visits, representing 143 unique patients, met study inclusion criteria and were included in our cohort (Fig. 1). Of the 145 visits, 138 (95.2%) were from men. The median age was 25 years (IQR, 21-38 years). Sixty-seven ED visits (46.2%) from 66 unique patients were associated with head or spine in- juries. 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 injuries. Of the 67 visits with head or spine injuries, 62 patients (92.5%) were wearing a helmet at the time of injury; information re- garding the use of chest protectors or cervical stabilization equipment at the time of the injury typically was not recorded.

Fig. 1. Flowchart of patient enrollment. Emergency department (ED) diagnoses (cases in the trauma registry) included “motocross,” “motorcross,” “motorbike,” and “dirt bike.” Numbers indicate ED visits.

Imaging studies

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.

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 imaging, including skull fracture (n = 2), subdural hematoma (n = 1), subarachnoid hemorrhage (n = 4), intraparenchymal hemor- rhage (n = 3), and diffuse axonal injury (n = 3). Patients with head in- juries were most frequently admitted to the general surgical floor (n = 18 [41.9%]) and the intensive care unit (n = 12 [27.9%]).

Spine injuries

Forty-six ED visits were associated with spine injuries, including 32 acute spinal fractures (69.6%; transverse process fractures, n = 16; ver- tebral compression or burst, n = 16; and other types of vertebral frac- tures, 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. Twelve patients (26.1%) with spine injuries were admitted to the intensive care unit, and 11 (23.9%) were taken to the operating room di- rectly from the ED.

Head and spine interventions

Table 1

Emergency department visits-baseline characteristics and outcomes^a.

Variable ED visits

All (N = 145) Head injuries

(n = 43)

Age, y Male sex	25 (21-38) 138 (95.2)	27 (21-40) 41 (95.3)	25.5 (21-38.5) 43 (93.5)
ED Glasgow coma scaleb
3	3 (2.1)	3 (7)	2 (4.35)
4-8	2 (1.4)	2 (4.7)	0 (0)
9-14	3 (2.1)	3 (7)	2 (4.35)
15	135 (94.4)	35 (81.3)	42 (91.3)
Head injury (n = 43)
Loss of consciousness	…	33 (76.8)	…
Concussion	…	36 (83.7)	…
Skull fracture	…	2 (4.7)	…
Epidural hematoma	…	0 (0)	…
Subdural hematoma	…	1 (2.3)	…
Subarachnoid hemorrhage	…	4 (9.3)	…
Intraparenchymal hemorrhage	…	3 (7)	…
Diffuse axonal injury	…	3 (7)	…
Spine injury (n = 46) Acute spinal fracture	…	…	32 (69.6)
Epidural hematoma	…	…	4 (8.7)
Acute disc herniation	…	…	1 (2.2)
Ligamentous injury	…	…	5 (10.9)
Cervical strain	…	…	3 (6.5)
Thoracolumbar strain	…	…	10 (21.7)
CT imaging
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)
ED disposition
Home	40 (27.6)	7 (16.2)	4 (8.7)
General surgical floor	53 (36.5)	18 (41.9)	19 (41.3)
Intensive care unitc	21 (14.5)	12 (27.9)	12 (26)
Operating room	31 (21.4)	6 (14)	11 (24)
Head or spine intervention or	10 (6.9)	5 (11.6)	8 (17.4)

Spine injuries (n = 46)

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).

surgery

Persistent neurologic deficit at hospital discharge

7 (4.8) 5 (11.6) 4 (8.7)

Seven patients (4.8%) underwent specific interventions for the spine (spinal fusion, n = 5; placement of an extension cast, n = 2).

functional outcomes“>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 hospi- tal discharge. Among the patients with persistent neurologic deficits, 2 patients had paraplegia due to complete spinal cord injuries after 3 col- umn fractures of the thoracic spine, and 2 patients had a severe TBI with cognitive deficits, including impaired memory, orientation, and com- prehension. Another patient with severe TBI was in a persistent vegeta- tive state and was discharged to a nursing facility. Two patients were discharged home with less severe injuries; one had persistent numb- ness consistent with an injury to the mAxillary nerve division of the tri- geminal nerve (due to an orbital fracture) and one had persistent mild right upper-Extremity weakness due to an acute C7 superior facet frac- ture. All patients 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 cervical stabilization was not specifically recorded. Table 1 summarizes patient characteristics, injuries, and outcomes.

Discussion

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

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)

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.

(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 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 Recreation and the Environment of off-highway vehicle recreation (including off-road motorcycles) estimated that an average of 18.6% of the population annually participated in off-highway vehicle recreation- al driving between late 1999 and 2007 [18]. Motocross has one of the highest Incidence rates for injuries compared with other high-impact sports [3]; the average yearly percentage of injuries is around 10%, whereas in bicycling, car racing, motorboat, downhill ski, and equestri- an sports, it is b 2%. Data from the National Electronic Injury surveillance System of the Consumer Product Safety Commission (2000 - 2011) showed that across 7 extreme sports, motocross had the highest inci- dence of neck fractures and accounted for 27.67% of all reported neck fractures, but when compared with snowboarding, snow skiing, and skateboarding, motocross was associated with fewer concussions [11].

The number of injuries associated with motocross has increased [11,12] with increasing participation.

The majority (95%) of patients in our study were young men; this finding was consistent with those of an observational study from South- ern California [2] and a 12-year descriptive study [3]. According to our findings and previous studies, adult patients with motocross-related in- juries 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 N 80% having a concussion, despite all wearing a 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 up- date in current guidelines and definitions of concussion and TBI might have resulted in underdiagnosis [3]. Our relatively higher rates of head injuries may be due to our inclusion criteria, which were restricted to in- juries that occurred in a motocross track and in patients who presented to a tertiary hospital ED.

Among those patients with head injuries, we observed a high rate of concussion (83.7%), with most associated with LOC. Our findings are similar to a study of pediatric patients with motocross injuries, which was 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]. More than 90% of those head injuries were concussions, and almost all children had LOC. Together, these findings suggest more severe injuries and potentially worse long-term outcomes in pa- tients with motocross-related head injuries because sports-related con- cussions generally occur without LOC [17]. LOC in patients with concussion has been associated with early 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 inju- ries. Luo et al. [5] reported that N 60% of young motocross riders who re- ported Concussion symptoms continued riding on the same day.

In a North American observational study of motocross injuries con-

ducted from 2000 through 2001 [2], 14% of patients had spine injuries, 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 co- hort (70% had at least one CT of the spine) and possible variation in def- initions across studies (we included sprains of the spine in our definition).

A large Cochrane systematic review of on-road traumatic injuries re-

ported a 42% decreased incidence of death and 69% decreased incidence 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 mo- tocross riding. Even though our state does not require helmets for off- road riders older than 18 years [22], helmet usage is possibly the reason why patients did not have worse injuries.

Emergency providers need to be aware of the high rates of head and spine injuries in this population, despite the use of protective equip- ment, to facilitate early recognition and management of these patients. It is important to determine whether patients have an improvement or deterioration in neurologic status since the time of injury and determine the need for emergent neuroimaging to exclude severe injuries [17]. The high usage of head and spine CT during the ED evaluation could repre- sent a good 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 pedi- atric 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 operating room from the ED. The National Electronic Injury Sys- tem-All Injury Program data from 2001 to 2004 showed that for pa- tients 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 5.6%) [24]. Motocross areas were de- fined as a motocross park, race track, motorcycle park, or unspecified off-road location if the activity involved racing or jumping with motor- cycles; off-road areas were defined as woods, field, trail, backyard of home, and other specific off-road locations. The 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 neurologic in- jury, which affected almost 5% of our cohort. These injuries are poten- tially fatal, and the mortality rate was 1% in a mixed population of adults and children [2], similar to our mortality rate of 0.7%.

Limitations

This study has several limitations. We conducted a retrospective ob- servational (descriptive) study using data extracted from EHRs. No comparison cohort was used. Data were not captured for research pur- poses and thus are only as accurate as the record itself. Use of safety equipment (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.

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

Conclusion

Adult patients evaluated in the ED after motocross trauma had high rates of head and spine injuries and marked levels of morbidity and mortality. An increased awareness of the dangers associated with moto- cross and increased development of safer equipment are needed. Pro- spective research that identifies characteristics specifically predictive of these injuries might help focus on a target population and facilitate development of new state or national policies to decrease the consider- able morbidity and mortality resultant from these injuries.

Disclosures

None.

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