Incidence and Injury Types in Motorcycle Collisions Involving Deer in Western New York
Motorcycle popularity, urban sprawl, and large deer populations result in a significant number of deer–motorcycle collisions. This retrospective review of a level I trauma center in Buffalo, New York, revealed that 40 of 487 (8.2%) of patients admitted because of motorcycle crashes from May 2007 through June 2011 involved deer. There were 120 total injuries: the most common were orthopedic (39/120; 32.5%), chest (38/120; 31.7%), head (18/120; 15.0%), spine (10/120; 8.3%), facial (8/120; 6.7%), and abdominal (7/120; 5.8%). Thirty-five of 40 (87.5%) were men and were older (48.9 years, [SD, 8.9 years]) than the average for all motorcycle crashes during the study period (41.9 years, [SD, 13.9 years]). Mean (SD) injury severity score was 17.1 (9.8), reflecting the severity of encountered injuries. This study highlights the relatively common risk that deer pose to the motorcyclist and is comparable to published series in more rural Midwestern settings.
The combination of urban sprawl and a large deer population has caused deer–motor vehicle collisions to become a major concern over the past few decades. According to State Farm Insurance industry data, New York State drivers in 2010-2011 had a 1 in 149.5 likelihood of colliding with a deer over the year, compared with a national average of 1 in 183.4.1 Reports from the Midwest have highlighted the frequency and severity of this type of accident.2-4 Frequent performance of orthopedic procedures in this subset of trauma patients prompted a local review to determine the frequency and severity of injuries. This series differs from the Midwest studies in the existence of a universal helmet law for all motorcyclists and passengers in New York State. Other studies looking at this type of accident were performed in states, including Minnesota and Wisconsin, that require helmets only for riders younger than 18 years or persons with an instructional permit.5
The Erie County Medical Center (ECMC) is a level I trauma center located in Buffalo, New York, and serves much of western New York, as well as part of northwestern Pennsylvania and, occasionally, southern Ontario, Canada. Because the ECMC receives almost all major trauma cases in the region, we had sufficient records to explore the incidence and the severity of deer–motorcycle accidents in these regions. In addition to adding to the limited data analyzing crash outcomes, we also looked at the numbers and proportions of motorcycle accidents attributable to deer and compared these with results from studies from different geographical regions. Because the number of registered motorcycles in Erie Country is among the highest in New York State, and because of the increased severity of motorcycle–deer collisions relative to other motor vehicle–deer collisions, this issue has both safety and financial considerations.
Materials and Methods
A retrospective review of records from ECMC was performed to capture all records from motorcycle accidents from May 2007 through June 2011. The population was identified to include only motorcycle accidents that were caused by collision with deer.
Injury severity was standardized using the Injury Severity Score (ISS), and the level of consciousness on arrival was standardized using the Glasgow Coma Scale (GCS). Chart abstraction included patient age, identification of the patient as driver or passenger of the motorcycle, use of helmet, time of year, types of injuries, length of hospital stay, and whether the patient lost consciousness. Patient age was also abstracted for the entire initial screen of all motorcycle accidents regardless of mechanism.
Statistical analysis was done using SPSS (IBM SPSS Statistics for Windows, Version 19.0; IBM Corp., Armonk, New York). Continuous data were analyzed using the appropriate descriptive statistics. Comparisons were made using Student t test, and a 0.05 level of significance was accepted.
Results
The initial screening of the trauma database returned 487 patients who had been involved in a motorcycle accident; of these, 39 patients were in an accident that involved a deer. According to one medical record, the spouse of a patient was a passenger who was dead at the scene, although there was no separate medical record for this person; this person was included in our data. Therefore, our total study population numbered 40 patients involved in 36 accidents, with 36 drivers and 4 passengers; 35 were men and 5 were women, with the women accounting for all 4 passengers and 1 driver. The mean (SD) patient age for deer–motorcycle collisions was 48.9 (8.9) years (range, 21-64 years). This was significantly higher than the mean (SD) age for all motorcycle accidents from the ECMC trauma database, which was 41.9 (13.9) years (range, 17-79 years) (P < .002).
The majority of accidents (31; 86%) with deer occurred during the months of May through September, with the most occurring in June (11; 31%). There was only 1 (3%) in October, 3 (8%) in November, and 1 (3%) in January. The number of collisions per year averaged 9.75, with a range of 8 to 12 from 2007-2010. (The year 2011 was omitted because data were collected before the year was complete). The presence or absence of helmet use was recorded in 22 cases. Of these, 21 patients had been wearing a helmet (95%), and only 1 patient was unhelmeted. Among all riders involved in motorcycle accidents from the trauma database, the presence or absence of a helmet was recorded in 271 cases. Of these, 262 (97%) were wearing a helmet. The average length of hospital stay was 6 days, with 6 patients having stays that were 10 days or longer, and the longest stay was 31 days. Thirty-three medical records noted whether the patient described loss of consciousness after the accident; of these, 14 (42%) claimed loss of consciousness and the remaining 19 (58%) denied any loss of consciousness after the accident. The mean (SD) ISS for deer–motorcycle collisions was 17.1 (9.8), and the mean (SD) GCS was 14.3 (2.5).
