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Maxillofacial Injuries from Moose/Motor Vehicle Collisions

December 1, 2005
by Bruce R. Pynn, MSc, DDS, FRCDC; Tania P. Pynn, RN, BScN, MHS; George K.B. Sandor, MD, DDS, PhD, FRCD


ABSTRACT

The incidence of moose/motor vehicle collisions have been on the rise in Northwestern Ontario over the past several years. Collisions with these large, high animals, either directly or indirectly, produce several unique management challenges for physicians, surgeons and dentists. Moose/ motor vehicle collisions are associated with a significant morbidity and mortality. We describe a case of multiple facial injuries in a husband and wife associated with a moose/motor vehicle collisions and review the literature concerning this interspecies interaction.

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CASE REPORT

During a clear fall evening, a small pickup truck was traveling along Hwy. 11/17 in Northwestern On tario. A bull moose darted out of the bushes along the roadside into the path of the truck. The moose was hit in the legs, propelling it onto the hood and its body smashing into the windshield (Fig. 1). The moose died instantly. The shattered windshield perforated the moose’s abdomen, spraying contents everywhere. Both the driver and passenger (husband and wife) sustained major facial fractures, lacerations and minor orthopedic injuries.

The initial clinical examination in the emergency room revealed that the driver sustained a combination of LeFort II and III fractures and associated nasal fractures. The passenger incurred a complex nasomaxillary fracture with a laceration through the upper and lower eyelids (Figs. 2A & B). The laceration was littered with glass fragments, entrails, twigs and dirt. Both patients had emergency CT scans. The scan of the passenger confirmed the presence of numerous glass fragments that were embedded in the laceration (Figs. 3A & B) and an ophthalmologist was consulted. Ophthalmic examination revealed that the eye was intact with minimal orbital inflammation, although the lower lid was lacerated through the tarsal plate.

The driver was taken to the operating room first, where the LeFort fractures were repaired by open reduction and fixation through a combination of incisions in the eyebrow, on the lower eyelid and intraorally using an incision in the buccal vestibule. The nasal fracture was supported by an external splint. The passenger was then taken to the operating room, where the debris and glass was gently removed, and the fracture was repaired through the laceration.

Both patients were followed for more than two years and are both doing remarkably well. The passenger still has mild ectropion from the contracture of the laceration. This could be repaired with a Z-plasty but the patient declined further surgery for the time being.

DISCUSSION

The incidence and patterns of facial bone fractures vary according to the geographic locations where the patients have sustained their trauma.1-4 There are places in the world where such facial fractures are likely to result from motor vehicle collisions with larger wild animal species. The incidence of motor vehicle collisions that are caused by large animals affecting motorists appears to be increasing. Globally, the most common large animals involved in motor vehicle collisions depend on the geographic location.5 These large animals include: kangaroos in Australia; camels in Saudi Arabia; and moose, deer, reindeer and bear in parts of Europe, Japan, the United States, and Canada. Northwestern Ontario (NWO), an area the size of France, has a significant number of collisions with large wild animals each year. Likewise in Europe such accidents are particularly problematic in Sweden and Finland. In the Oulu region of Lapland in Finland there were an estimated 422 collisions involving moose species so far in 2005.6

By definition, a wildlife-motor vehicle collision (WMVC) is a result of a motor vehicle hitting an animal or hitting another object in an attempt to avoid the animal. Large animal (moose, reindeer, deer, bear) wildlife motor vehicle collisions account for the majority of reported animal collisions and cause the greatest damage to private property and human life. Collisions with smaller wildlife species may occur by the thousands, but as they cause less damage than large animals, they rarely appear in statistics.

A true calculation of WMVC is hard to document as not all collisions are reported. It is estimated that in North America, a collision with large animal wildlife happens every minute of each hour. Internationally, WMVCs are commonplace and the incidence tends to be higher in areas where the migration patterns of various wildlife populations meet with the extensions of highway networks, traffic volume, and speed increases. In Europe there are about 1 million animal-vehicle collisions a year. In the USA, there are approximately 730,000 deer-vehicle related collisions alone. In six Canadian provinces, 35,000 cases have been reported, which is a gross underestimate of the total incidence across the country. Provincially, approximately 18,500 wildlife-vehicle collisions are reported annually. In 2002, NWO experienced 3,500 motor vehicle collisions with one third of these collisions involving wildlife. Of these, approximately 600 deer, 400 moose, and the rest of varying species were involved in the wildlife-motor collisions. These WMVCs have shown a slow steady increase for each of the past five years in NWO.

The most frequent types of animal involved in collisions are generally large, long-limbed ungulates or hoofed mammals. A moose for example can weigh up to 1,600 pounds and can stand eight feet tall. Large species are more vulnerable to motorists because they tend not to be afraid of oncoming headlights, are less agile than small wildlife, and have unpredictable movements. Headlights have limited reflection from the eyes of these ungulates and their dark fur camouflages them at night. There are more than 100,000 moose in the Province of Ontario.

Approximately 70 percent of WMVCs occur over the summer and fall, between June and October. For moose and deer, this corresponds to their “rutting” season. The mating season increases their activity and thus their travel across roadways. Moose and deer are also attracted to areas near highways to avoid flies, lick road salt, feed on vegetation, and travel the roads in winter to avoid deep snow. Seventy-five percent of WMVCs occur between dusk and dawn as this is the time when driver visibility is limited by darkness, and when many of the wildlife are most active. These collisions also occur when driving conditions are good, with dry straight sections of roads, and clear nights. Under such ideal conditions, the attention of the driver may be decreased, increasing their risk of a collision.

While almost always fatal to the wildlife species, WMVCs result in up to three deaths per year in NWO. These collisions cost insurance companies more than $20 million per year in claims. The injuries are dependent on the speed of which the automobile was traveling and animal species hit. The mechanism and pattern of injuries varies as a result of direct or primary and indirect or secondary collisions.

In a direct collision, the moose is struck at its relatively skinny legs, causing the massive body of the moose to roll onto the hood of the vehicle and collapse into the windshield and roof (Fig. 4). The animal’s carcass is left lying in the driver’s or passenger’s lap. Direct collisions with large animals tend to produce characteristic injury patterns. The injuries are caused by the contact between the animal and the victim’s head and upper torso for which seat belts are not protective. Midface fractures including LeFort I, II and III fractures, dento-alveolar fractures, multiple facial lacerations, significant closed head injuries, cervical spinal injuries, and minor orthopedic injuries generally in the upper limbs have been reported.5,7

An indirect collision is caused by a driver trying to swerve to miss the large animal, colliding with other vehicles or stationary objects. In some cases, the animal may be hit by one car then is thrust into oncoming traffic. Indirect collisions are
similar to other types of motor vehicle collisions. The patterns of injury are less predictable.

The maxillofacial and ocular injuries associated with large animals and motor vehicle collisions are usually complex and require a multidisciplinary approach, with the involvement of trauma teams consisting of general surgeons, orthopedic surgeons, oral and maxillofacial surgeons, ophthalmologists and dentists. Treatment consists of management using the acute trauma life support protocol developed by the American College of Surgeons. There are then wound management issues as the practitioner must be aware of the significant risk of infection with gram negative, gram positive and clostridial organisms from the animal fur and feces, entrails, glass and other foreign bodies. The facial fractures are repaired with open reductions where appropriate using rigid fixation techniques to promote a faster recovery. The dental injuries are treated emergently and then dealt with definitively once the patient’s condition permits.

Road safety and public education are important steps in primary prevention of WMVCs.8 The formation of numerous prevention coalitions across the world has shown how effective collaborative efforts of community partners can be to help eliminate preventable injuries such as those caused by WMVCs. The Highway Safety Education Committee in NWO is one example of a coalition that promotes the message of safe driving on the highways through various forms of education such as radio, newspapers, placemats, presentations and posters. A campaign entitled: “Moose on the Loose” has resulted in the erection of several 8 foot wide x 12 foot high signs in areas statistically shown to have the highest number of animal strikes in NWO (Fig. 5). The coalition has also used these methods of education to increase the public’s awareness of animals mating seasons, evasive driving techniques, and the use of seat belts. This new approach was designed to remind residents of the dangers of WMVCs and to enhance initiatives already in place.

Many areas in Canada and Finland have suggested more stringent interventions, such as dedicated wildlife under- and overpasses in areas where animals frequently cross. Fencing of hundreds of miles of highway to prevent wildlife from crossing roadways has been one solution employed in Sweden and Finland. These solutions may not be practical in large open places like Western Australia and NWO. Several small-scale preventative measures such as reflectors, ultrasonic whistles, vegetation management to improve visibility, and warning signage may also help decrease these collisions. However, the relative effectiveness, and cost of different methods is poorly understood. Evaluations regarding the effectiveness are lacking and based mainly on opinion, which leaves skepticism on specific implementation strategies.

Another solution to reduce injuries is improving the structure of vehicles. Many drivers in Western Australian add ‘roo-bars’ to the front of their vehicles for added protection. Large haul drivers in Canada have added similar protective frames to the front of their rigs. Car manufacturers like Volvo and Saab have developed high penetration resistant windshields as well as improved their windshield struts to prevent collapse of the roof. These strategies aside, the mainstay of improving road safety is by reducing speed, improving driver awareness while driving during dusk to dawn, and obeying signage when entering wildlife habitat or crossings. These basic actions coupled with public education awareness campaigns surrounding the incidence, implications, and prevention of WMVCs are key steps in abolishing this problem.

It should be noted that these collisions occur at any time and are a real threat to all the motoring public. Caution should be taken when driving in rural areas. The reduction of speed is one’s best defense against serious injury or loss of life. Drive Safe Stay Alert!!

Acknowledgements

We would like to thank retired OPP Staff Sargent Bob Beatty for the traffic statistics and Diane Scott of the University of Toronto for her illustration.

Bruce R. Pynn is an Oral and Maxillofacial Surgeon, Thunder Bay Regional Health Science Centre, Thunder Bay, ON.

Tania P. Pynn is a Public Health Nurse, Thunder Bay District Health Unit, Thunder Bay, ON.

George K.B. Sandor is Professor, Oral and Maxillofacial Surgery and Anaesthesia, University of Toronto; Coordinator of Pediatric Oral and Maxillofacial Surgery, The Hospital for Sick Children and Bloorview MacMillan Children’s Centre. Dosent, University of Oulu, Oulu, Finland.

Oral Health welcomes this original article.

REFERENCES

1.Pynn, BR, Green RA, Dowhos WW. Responding to trauma. Ontario Dentist 2003; 9:23-28.

2.Sojat AJ, Meisami T, Sandor GKB, Clokie CML. The Epidemiology of Mandibular Fractures: A Review of 246 cases. Journal of the Canadian Dental Association 2001; 67(11): 640-644.

3.Oikarinen K, Schutz P, Sandor GKB, Safar S, Sojat AJ, Clokie CML, Meisami T, Moilanen M, Perheentupa U, Belal MS. Differences in the etiology of mandibular fractures in Kuwait, Canada and Finland. Dental Traumatology 2004; 20(5): 241-245.

4.Oikarinen K, Schutz P, Thalib L, Sandor GKB, Schutz P, Clokie CML, Safar S, Meisami T, Perheentupa U. Differences in the location and multiplicity of mandibular fractures in the 1990’s in Kuwait, Canada and Finland. Medical Principles and Practice 2005; 14(1): 10-15.

5.Pynn BR, Dowhos WW, Affleck A. Maxillofacial injuries from moose/motor vehicle collisions in Northwesten Ontario, Canada. Int J Oral Maxfac Surg 2003; 32: (Suppl) 55.

6.Personal communication Finnish Police Oulu, Finland.

7.Sit, M, Pynn, B Webb M, Schoales B, Hurwitz M, Hurwitz JJ. Ocular injuries in a victim of motor vehicle collision with a moose. Canadian Journal of Ophthalmology 2005; 40:200-203.

8.Pynn TP, Pynn, BR. Moose and other larger animal wildlife vehicle collisions: Implications for prevention and emergency care. Journal of Emergency Nursing 2004; 30: 542-547.


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