ELSEVIER Clinical Neurology and Neurosurgery 98 (1996) 281-285

Head injuries from bicycle accidents

Josef Zentner”, Heike Franken, Gregor LGbbecke

Department of Neurosurgery, University of Bonn, Bonn, Germany

Received 26 February 1996; revised 31 May 1996; accepted 31 May 1996

Clinical Neurology and Neurosurgery

Abstract

This study comprises a total of 159 victims from bicycle accidents treated as inpatients at the Department of Neurosurgery, University of Bonn between January 1987 and June 1995. It was our aim to define the severity and features of bicycle-related head injuries in a defined population. Our results show that 33% of admitted bicycle victims sustained severe head injuries (Glasgow Coma Score 3-S). Neurosurgical (operations were performed in 49% of patients and were mainly related to the evacuation of an extracerebral hematoma. Of the 159 bicycle victims, 112 (70%) made a good recovery, 11 (7%) remained moderately and 4 (3%) severely disabled, and 26 (16%) had died at follow-up (mean 2 years). In conclusion, our data indicate that bicycle-related trauma accounts for a substantial proportion of all head injuries requiring neurosurgical treatment. Active (e.g. traffic regulations, education of riders) and passive measures (e.g. safety helmets) can be expected to reduce both incidence and severity of head injuries among bicyclists.

Keywords: Head injury; Bicycle accident

1. Introduction

Both for recreation and transportation, bicycling en- joys increasing popularity. In consequence, bicycle-re- lated injuries are receiving more attention as a public health issue. One third of all victims of bicycling acci- dents treated in emergency rooms have head injuries, as have two thirds of all patients with bicycling accidents admitted to hospital [1,9,11,14]. Thus, bicycle-related trauma accounts for a substantial proportion of all head injuries [15], and actually, head injuries occur more frequently in accidents involving pedal cyclists than in those involving .motor cyclists [21]. Children are at higher risk than adults, and bicycle injuries are now the most common cause of hospitalization for head injuries in children [1,3,4,7,10,11,13,20]. In addi- tion, head injury is the primary or contributing cause in 70% to 85% of all bicycle-related fatalities [6,12,15,17]. In the light of these statistics this study was undertaken

*Corresponding author. Department of Neurosurgery, Sigmund- Freud-StraBe 25, 53105 Bonn, Giermany. Fax: (49) (228) 287-6573.

to define the severity and types of bicycle-related head injuries in a defined population.

2. Patients and Methods

From January 1987 to June 1995 a total of 1128 head-injured patients were treated as inpatients at the Department of Neurosurgery, University of Bonn. Among them 546 patients were victims of road acci- dents exclusive of bicycles, and 159 had bicycle crashes. There were 114 men (72%) and 45 women (28%), aged 3 to 81 years (mean age 34 years).

Medical charts were reviewed retrospectively. Data evaluated included details on the accident, severity of head injury, treatment modalities, and outcome. Data collection and evaluation were computerized (dBase+++). To standardize severity of head injury, the Glasgow Coma Scale was used [34]. The outcome was assessed according to the Glasgow Outcome Scale [S]. Long-term results were obtained by questionnaires. Observation time ranged from 6 to 96 months and aver- aged 24 months.

0303-8467/96/$15.00 Copyright Q 1996 Elsevier Science B.V. All rights reserved. Z’ZZSO303-8467(96)00036-4

282 J. Zentner et al. I Clinical Neurology and Neurosurgery 98 (1996) 281-285

Patients (N)

cl0 IO-19 20.29 30-39 40.49 50-59 50-59 270

??bicycle accidents other road accidents Age (years)

Fig. 1. Age distribution of patients with bicycle (n= 159) and other road accidents (n = 546).

3. Results

A significant percentage (26%) of bicycle accidents were sustained by children aged between 10 and 19 years, while other road accidents mainly affected young adults (Fig. 1). Most bicycle injuries occurred in the warm seasons between May and September (Fig. 2). Thirty-eight percent of bicycle traumas were caused by crashes with cars, while in 8% other bicyclists were involved. No other vehicles were involved in 26% of accidents (Fig. 3). Fifty-nine percent of bicycle acci- dents occurred during the day (Fig. 4). Only a minor proportion of bicycle riders (4%) wore helmets at the time of accident. Alcohol played a role in 10% of bi- cycle crashes.

Isolated head injury was noted in 37 bicycle crashes (23%), whereas 122 riders (77%) sustained a polytrau- ma. Severity of head injuries in bicycle accidents as compared to other road accidents and the total group of head-injured patients is shown in Fig. 5. As it is

collision with cars

H collision with cycles

??with no others involved

Cl unknown

Fig. 3. Reasons for bicycle accidents

4

Fig. 2. Distribution of bicycle accidents over the year.

demonstrated, the proportion of severe head injuries (GCS 3-8) in bicycle crashes was somewhat lower than in other accidents, and vice versa for mild injuries (GCS 13-15). Of 159 bicyclists, 82 (52%) were primarily treated in the intensive care unit (ICU). Duration of stay on ICU was up to 1 week in 55 patients, between 1 and 3 weeks in 15 cases, and more than 3 weeks in 12 cases. Neurosurgical operations were performed in 78 of 159 bicyclists (49%). Most of these operations were related to the evacuation of an extracerebral hematoma (Table 1).

Of the 159 bicycle victims, 112 (70%) made a good recovery (GOS 5), while 26 [16] had died (Table 2). The outcome of 159 bicycle victims divided into the cate- gories ‘unfavorable’ (GOS l-3) and ‘favorable’ (GOS 4-5) and related to the age is shown in Fig. 6. Children aged between 10 and 19 years had a favorable outcome in a high proportion. Fifty-three percent of bicyclists achieved Karnofsky Score of 100 on long-term follow- up (Fig. 7).

Table 1 Diseases of 78 bicycle victims requiring operative treatment

Disease/procedure Patients

n %

Epidural hematoma 31 40 Subdural hematoma 19 24 Intracerebral hematoma 2 3 Impression fracture 4 5 Rhinoliquorrhea 7 9 Ventriculostomy 15 19

Total 78 100

Ventriculostomy was performed in 15 patients for measurement and treatment (release of cerebrospinal fluid) of increased intracranial pressure.

J. Zentner et al. I Clinical Neurology and Neurosurgery 98 (1996) 281-285 283

Table 2 Outcome of 159 bicycle victims assessed by the Glasgow Outcome Scale (GOS)

Outcome (GOS) Patients

n %

1 Death 26 16 2 Vegetatitve status 0 0 3 Severe disability 4 3 4 Moderate disability 11 I 5 Good recovery 112 70 Unknown 6 4

Total 159 100

4. Discussion

Population-based rates, of head injuries from bicycle crashes requiring hospitalization account for 12.5 to 13.5 per 100 000 with the highest incidence in children under the age of 15 [20,22]. Thus, head injuries from bicycling are an important problem that grows as cy- cling continues to increase in popularity. Although most bicyclists sustained mild to moderate injuries, our results clearly indicate that bicycle victims requiring neurosurgical care suffer serious head trauma in a large percentage of cases. Obviously, our data do not reflect the true incidence of different bicycle-related head in- jury patterns, since there is an unknown number of patients who have been treated either as outpatients or in other emergency rooms. Assuming that victims primarily undergoing neurosurgical care as inpatients have probably experienced a major head trauma, our figures certainly overestimate the real situation. How- ever, the relation of patients who undergo neurosurgical

(2:)

7a.m.-noon ??noon-6p.m.

0 6p.m.-7a.m.

El unknown

Fig. 4. Distribution of bicycle accidents over the day.

care as inpatients can be supposed to be similar among the different injury groups studied. Thus, we can state that bicycling today considerably contributes to mor- bidity and mortality in all head injuries. In the present series, bicycle crashes accounted for 23% of all road accidents, and 16% of the bicycle victims had died.

A retrospective study in which the authors recorded the injuries and the use of helmets over the previous 5 years, suggested that helmets decrease the risk of head injury by 33 to 56% [5]. Similar data have been

All head Injuries

N=1128

Bicycle accidents

N=159

Road accidents without bicycles N=546

478 471 182

(33%)

179 281

(16%) (I& (52%)

GCS 3-6 ??GCS 9-12 ??GCS 13-15

Fig. 5. Severity of head injury in the total group of head-injured patients (n = 1128), in bicycle accidents (n = 159), as well as in road accidents without bicycles (n = 546) assessed by the Glasgow Coma Scale (GCS).

284 J. Zentner et al. I Clinical Neurology and Neurosurgery 98 (1996) 281-285

Patients (N) 40 40

35

30

25

20

15

10

5

0

Fig. 6. Outcome (GOS) of 159 bicyclists related to age.

reported by others [5,16,19]. From the analysis of 235 cases of head injuries to bicyclists, Thompson [15] con- cluded that safety helmets reduce the risks of head in- jury by 80% and of brain injury by 88%. In other words, riders who do not wear helmets appear to be at 6.6-fold greater risk of head injury and an 8.3-fold greater risk of brain injury than riders who do [15]. Although the literature provides convincing evidence of the effectiveness of bicycle helmets to reduce severity of head injury, the acceptance of helmets is still limited. Only 4% of our bicycle victims wore helmets at the time of accident. Legislation mandating helmet use has been introduced in some communities [26,27], but it has been suggested that legislation without education is unlikely to be successful [28]. Community-wide campaigns in- cluding public announcements, distribution of educa- tion material, and discount coupons have proven to be useful tools for increasing the proportion of helmet wearers [20,22-25,27,29-321.

On the other hand, propagation of passive security, such as helmet-wearing may distract attention from the

PIid) 26

”

//

.

x

KS 0

KS 20-50

KS 60-90

KS 100

unknown

Fig. 7. Long-term outcome of 159 bicycle victims assessed by the Karnofsky Score (KS).

primary source of cyclists’ problems, namely the expo- sure to high volumes of motorized traffic moving at relatively high speeds [18,33]. Collision with cars was the cause of head injury in 38% of our bicycle riders. As Hillman [33] stated it seems unjust to pass respon- sibility for the safety of cyclists on the road to the cy- clists themselves as they are the far more vulnerable road users and are unable to control many potentially dangerous situations. An effective approach in making cycling safer lies in the provision of exclusive networks for cyclists. Where this is not possible, steps need to be taken to lower the speed of motor vehicles by traffic calming [15]. Resources are almost certainly better di- rected towards prevention of accidents rather than the limitation of the damage caused by them [15,33].

In conclusion, our data indicate that bicycle-related trauma accounts for a substantial proportion of all head injuries. Various recommendations have been made to reduce both the risks of accidents and the risks of injury. Active measures to prevent accidents include enforcement of traffic regulations, education of riders, the creation of bicycle lanes, and improved visibility of riders at night by reflectors. It may be years before all towns and cities have safe, uninterrupted, and ade- quately designed cycle networks where the risk of in- volvement in a collision of motor vehicle is minimized. Until then, good quality helmets may be a preventative short-term measure to reduce the severity of some head injury among cyclists.

References

[l] Armson, C.J. and Pollard, C.W. (1986) Child cyclist injuries: a prospective study. Med. _I., Aust. 144: 144146.

[3] Brown, B., Farley, C. (1989) The pertinence of promoting the use

[41

PI

WI

171

PI

191

VOI

[ill

of bicycle helmets for 8 to 12 year old children. Chron. Dis. Can., 10: 92-95. Cushman, R.A., Down, J., MacMillan, N. and Waclawik, H. (1990) Bicycle helmets use in Ottawa. Can. Fam. Phys., 36: 6977700. Dorsch, M.M., Woodward, A.J. and Somers, R.L. (1987) Do bicycle safety helmets reduce severity of head injury in real crashes? Accid. Anal. Prev., 19: 183-190. Friede, A.M., Azzara, C.V., Gallagher, S.S. and Guyer, B. (1985) The epidemiology of injuries to bicycle riders. Pediatr. Clin. North. Am., 32: 141l151. Ivan, L.P., Choo, S.H. and Ventureyra, E.C. (1983) Head injuries in childhood: a 2-year survey. Can. Med. Assoc. J., 128: 281- 284. Jennet, B., Bond, M. (1975) Assessment of outcome after severe brain damage, a practical scale. Lancet, 1: 48&484. Kruse, D.L. and McBeath, A.A. (1980) Bicycle accidents and injuries. A random survey of a college population. Am. J. Sports Med., 8: 342-344. Lapner, M. and Leslie, PI. (1981) Bicycle injuries in children. Can. Med. Assoc. J., 125: 132. O’Rourke, N.A., Costello, F., Yelland, J.D. and Stuart, G.G. (1987) Head injuries to children riding bicycles. Med. J. Aust., 146: 619-621.

J Zentner et al. I Clinical Neurology and Neurosurgery 98 (1996) 281-285 285

[12] Reynolds, R. and Cohen, D. (1987) Children, bicycles and head injuries. Med. J. Aust., 146: 615.

[13] Scaglione, N.A., Suljaga-l’etchel, K. and Frankel, V.H. (1983) Bicycle-related accidents and injuries in a population of urban cyclists. Bull. Hosp. Joint Dis., 2: 80-89.

[14] Simpson, W., Unwin, P.S. and Nelson, I.W.C. (1988) Head in- juries, helmets, cycle lanes, and cyclists. Br. Med. J., 296: 1161- 1162.

[15] Thompson, R.S., Rivara, F.P. and Thompson, D.C. (1989) A case-control study of the ~effectiveness of bicycle safety helmets. N. Engl. J. Med., 320: 13~51-1367.

[16] Wassermann, R.C., Waller, J.A., Monty, M.J., Emery, A.B. and Robinson, D.R. (1988) Bicyclists, helmets and head injuries: a rider-based study of helmet use and effectiveness. Am. J. Public Health, 78: 112t%ll21.

[17] Weiss, B.D. (1987) Childhood bicycle injuries, what can we do? Am. J. Dis. Child, 141: l:l5-136.

[18] Williams, A.F. (1976) Factors in the initiation of bicycle-motor vehicle collisions. Am. J. Dis. Child, 130: 37&377.

[19] Worrell, J. (1987) Head injuries in pedal cyclists: how much will protection help? Injury, 18: 556.

[20] Thompson, D.C., Thompson, R.S. and Rivara, F.P. (1990) In- cidence of bicycle-related injuries in a defined population. Am. J. Publ. Health, 80: 138881390.

[21] McDermott, F.T. and Klug, G.L. (1982) Differences in head injuries of pedal cyclist and motorcyclist casualities in Victoria. Med. J. Aust., 2: 30-32.

[22] Kraus, J.F., Five, D. and Conroy, C. (1987) Incidence, severity, and outcomes of brain injury involving bicycles. Am. J. Public Health, 77: 7678.

[23] Dannenberg, A.L., Cot& T.R., Kresnow, M.J., Sacks, J.J., Lip-

sitz, C.M. and Schmidt, E.R. (1993) Bicycle helmet use by adults: the impact of companionship. Public Health Rep., 108: 212-217.

[24] McDermott, F.T. (1984) Why pedal cyclists should wear safety helmets. Aust. Fam. Phys., 13: 284285.

[25] Bergman, A.B., Rivara, F.P., Richards, D.D. and Rogers, L.W. (1990) The Seattle Children’s bicycle helmet campaign. AJDC, 144: 727-731.

[26] Cote, T.R., Sacks, J.J. and Lambert-Huber, D.A. (1992) Bicycle helmet use among Maryland children: effect of legislation and education. Pediatrics, 89: 12161220.

[27] McDermott, F.T. (1991) Helmets for bicyclists: another first for Victoria. Med. J. Aust., 154: 156157.

[28] Parkin, P.C., Spence, L.J., Hu, X., Kranz, K.E., Shortt, L.G. and Wesson, D.E. (1993) Evaluation of a promotional strategy to increase bicycle helmet use by children. Pediatrics, 91: 772-777.

[29] Ozanne-Smith, J. and Sherry, K. (1990) Bicycle related injuries: head injuries since helmet legislation. Hazard, 6: l-8.

[30] DiGiuseppe, C.G., Rivara, F.P., Koepsell, T.D. and Polissar, L. (1989) Bicycle helmet use by children: evaluation of a commu- nity-wide helmet campaign. J. Am. Med. Assoc., 262: 22562261.

[31] Morris, B.A.P. and Trimble, N.E. (1991) Promotion of bicycle helmet use among school children: a randomized clinical trial. Can. J. Publ. Health, 82: 92-94.

[32] Hu, X., Wesson, D.E., Parkin, P.C. and Chipman, M.L. (1994) Current bicycle helmet ownership: use and related factors among school-aged children in Metropolitan Toronto. Can. J. Publ. Health, 85: 121-124.

[33] Hillman, M. (1992) Cycling: Towards Health and Safety. British Medical Association Report, University Press, Oxford.

[34] Teasdale, G. and Jennett, B. (1974). Assessment of coma and impaired consciousness. A practical scale. Lancet, II: 81-84.