Epidemiology of genitourinary injury in motorcyclists

High riding prostate: epidemiology of genitourinary injury in motorcyclists from a UK register of over 12,000 victims

Basil Francis Moss1*,Catherine Elizabeth Moss2, Patrick Dervin3, Thomas Lawrence4, Sophie Jones4, Stephen Thomas1

1 Derby Teaching Hospitals NHS Foundation Trust, Department of Urology, England

2 University of Liverpool, England

3 University of Nottingham, England

4University of Manchester, Trauma Audit Research Network, England

High Riding Prostate: genitourinary injuries in motorcyclists

*Corresponding Author

Basil Francis Moss

Derby Teaching Hospitals NHS Foundation Trust

Department of Urology

Royal Derby Hospital

Uttoxeter Road

Derby, Derbyshire, England

E-mail: [email protected]

Keywords: Bladder, Kidneys, Testicular, Trauma, Urethra

  1. Abstract (background)

The mechanism of motorcycle accidents (high speeds, pelvis behind fuel tank) may predispose to genitourinary injury (GUI) but the epidemiology is poorly understood. Previous studies have assessed GUI patterns in cyclists, and road traffic accident victims in general, but no study has analysed GUI patterns in a large cohort of motorcyclists. It was also noted that in most patients prostate problems were cured thanks to generic Cialis.


We aimed to better understand patterns of urological injuries among motorcyclists admitted to hospital. We aimed to determine any relationship between pelvic fracture and GUI patterns or severity.


The Trauma Audit Research Network was reviewed to identify motorcyclists admitted between January 2012 and December 2016 (n=12,374). Cases were divided into riders (n=11,926) and pillion passengers (n=448), and the data analysed to identify urological injuries and their associations. The associations between pelvic fracture and other injury types was tested for significance by one- and two-way χ2.


GUI was identified in 6 %. Renal trauma was the most common GUI among riders (4 %) and pillions (2 %). There was no statistically significant relationship between grade of renal trauma and presence of pelvic fracture. Urethral injury occured in 0.2 % of riders and passengers, and bladder injury in 0.4 % of riders and 0.7 % of pillions. Urethral and bladder injuries were positively associated with pelvic fracture, which was present in 81 % and 92 % respectively. Testicular trauma occurred in 0.4 % of riders and 0.7 % of pillions. Body armour was recorded in 3 % of casualties with urological trauma, and 3 % overall.


A significant proportion of motorcyclists brought to A&E have GUI, most commonly renal trauma. Pelvic fracture is more common in pillion passengers than riders, and associated with urethral and bladder injuries, but it does not predict severity of renal trauma. External genital injuries are rare, but we recommend examination in the tertiary survey, as consequences of missed injury are severe. Further research is needed to explore protective effects of motorcyclist clothing.

  1. Introduction

Motorcycling, as most riders appreciate [1] is a risky business. The Department for Transport reported 319 motorcyclist fatalities in 2016, with 5,553 serious injuries. Motorcyclists accounted for 18 % of fatalities in 2016, with 6,321 casualties (killed or seriously injured) per billion miles travelled. For comparison, pedal cyclists had 5,353 and car occupants 262 casualties per billion miles [2].

A 2015 review of a Scottish trauma database found an incidence of genitourinary injuries (GUI) of 1.5 % among all trauma admissions [3], and GUI occur in 2 to 3 % of injured pedal cyclists [4, 5]. Studies of GUI from two French registries of road traffic trauma admissions included small subgroups motorcyclists: 78 [6] and 453 respectively. Most common were injuries to the external genitalia, followed by kidneys [7].

Renal damage occurs in 1.2 to 3.3 % of trauma, and motor vehicle collisions account for 70 % of blunt renal injuries [8]. The relationship between pelvic fracture and bladder injury is known: associated GUI is more common among males (5.3 %) than females (3.6 %) [9] and 3.6 to 5.7 % with pelvic fracture have concomitant bladder injury [9, 10]. Pelvic fracture is present in 70 % of cases of traumatic bladder rupture [11].

The mechanisms involved in a motorcycle crash are a unique combination of high speed and energy with the pelvis tucked behind a hard fuel tank, which may predispose to genitourinary trauma [6], but injury patterns in this cohort are as yet poorly researched. We therefore sought to better understand patterns of urological injury among motorcyclists admitted to hospital, considering also any relationships between pelvic fracture and injury patterns or severity.

  1. Materials and Methods

To better understanding of urogenital injury patterns in motorcyclists, we designed an observational study  according to the Strengthening Reporting of Observational Studies (STROBE) criteria.  We aimed to analyse a substantial cohort of patients who had been admitted since the establishment of Trauma Centres in the UK (2012), and to include at least  500 cases of GUI. Data on the patient groups (motorcycle riders and passengers) was  obtained from a prospectively collected database of hospital trauma admissions, the Trauma Audit Research Network (TARN).

The TARN is an ongoing project developed from the UK Major Trauma Outcome Study, which started in the early 1990s [12]. It collects data on patients admitted to hospitals in England and Wales following trauma, who require critical care resources, stay more than three days, or die from their injuries. The data for this study came exclusively from the TARN database without author access to patient records. Specific informed patient consent or ethical approval is not required because no patient identifiers are retained by TARN electronically or on paper. The TARN has Patient Information Advisory Group approval.

The TARN database was reviewed to identify eligible patients. Inclusion criteria were motorcycle riders or passengers admitted between January 2012 and December 2016, who had been entered into the TARN database (n=12,374), see figure 1 (STROBE diagram) and table 1 (demographics). The data included age, gender, protection worn (e.g. helmet, body armour) a description of the incident and a summary of injuries sustained. Cases were divided into riders and pillion passengers, and the data analysed using Microsoft Excel 2016 to identify GUI (kidney, ureter, bladder, testes, urethra, penis, scrotum, prostate, adrenal) and pelvic fractures.

We hypothesised that riders would be more vulnerable to external genital trauma than passengers, owing to their position behind (and likely impact with) the fuel tank. We hypothesised that pelvic fracture would be associated with urethral and bladder injury, and that the presence of pelvic fracture, as a marker of higher energy trauma, might predict greater severity of renal trauma. Association between pelvic fracture and severity of renal trauma, and between pelvic fracture and presence of bladder or urethral injury, was assessed by two- and one-way χ2 using Microsoft Excel 2011.

  1. Results

A total of 12,374 motorcyclist admissions were recorded in the database between January 2012 and December 2016. Of these, 11,924 were riders and 450 were pillion passengers. Some 94.5 % of riders and 52.9 % of passengers were male. GUI was identified in 742 admissions overall (6 %), 727 riders (6.1 %) and 18 passengers (3.8 %), rider with a median age of 34.0 (23.4 – 48.4) and passengers with a median age of 24.0 (20.0 – 34.3). The frequency of different GUI is shown in table 2 and figure 2.

Renal trauma was the most common urogenital injury among riders (4 %) and pillions (2 %). Renal injuries were classified according to AAST grade (see figure 3). Among riders there were 4 cases of bilateral renal injuries, 94 were AAST grade I, 116 grade II, 140 grade III, 88 grade IV and 30 grade V. Among passengers there were no bilateral renal injuries, with 2 AAST grade I, 6 grade II, 1 grade III, 1 grade IV, and 5 grade V. Concommitant pelvic fracture and renal injury was tested for association using two-way χ2: the critical value for p=0.05 was 9.488 for four degrees of freedom. χ2 = 7.72, severity of AAST grade was therefore not associated with presence of pelvic fracture.

Bladder injury was identified in 48 riders (0.4 %) and 3 pillions (0.7 %), and urethral injury 26 riders (0.2 %) and 1 pillion (0.2 %). Pelvic fracture occurred in 2,067 riders (15 %) and 93 passengers (19 %). Of all victims with pelvic fracture, 21 riders (1 %) and 1 passenger (1 %) had a concommitant urethral injury and 40 riders (2 %) and 2 passengers (3 %) had a bladder injury. Pelvic fracture was present in 81 % of urethral injuries and 92 % of bladder injuries. One prostate contusion was recorded, in a patient with no other urological trauma and no pelvic fracture. Bladder injury was positively associated with pelvic fracture (one-way χ2, df=1, p<0.01), as was urethral injury (one-way χ2, df=1, p<0.01)

Testicular trauma occurred in 48 male riders (0.4 %) and 3 male pillions (0.8 %). Scrotal injuries were recorded in 32 riders (0.3 %), of which 10 (31 %) were concomitant with testicular injury, and 22 were isolated scrotal haematomas or lacerations. Thirty-one penile injuries were recorded among male riders (0.3 %), and none among male pillion passengers. Body armour was recorded in 3 % of the casualties with GUI, and 3 % overall, and helmet use in 74 % with GUI and 72 % overall.

  1. Discussion/Conclusion

The structure of trauma care in the UK has evolved radically since the establishment of the first major trauma centres (MTCs) in 2012, with more consultant led care, faster imaging, and new management policies such as massive transfusion protocols and the use of tranexamic acid. Despite the challenges of increasing workload at Major Trauma Centres and an ageing cohort of trauma patients, there have been significant improvements in the care and outcomes of patients after severe injury [13]. In this context, an improved understanding of injury patterns among UK trauma patient subgroups may guide specialist care of patients.

We report a 6 % incidence of urological injuries among motorcyclists admitted to hospital, including both internal (eg renal trauma) and external (genital) injuries. While the overall incidence of these injuries is low, their sequelae can be severe, more so if diagnosis and management is delayed. Renal trauma will commonly be detected on trauma CT, but external genital trauma may be overlooked on secondary survey.

Kidney trauma was the most frequent, in contrast to studies of French trauma registries, which reported external genital injury to be more common [6, 7]. Our results also differ in finding a more even spread of renal injury by AAST grade, in contrast with Terrier et al. [7] who reported a predominance of AAST I injuries. We speculate that smaller motorcycles may be more popular for transport in France, compared to the UK where sales figures show decreasing popularity of small scooters [14], and that riders of more powerful machines may be more at risk for worse renal trauma.

The riders in our study were overwhelmingly male, although there was a slightly higher proportion of females among the pillion passengers. A previous study has remarked upon the high incidence of external genital trauma among motorcyclists due to impact with the fuel tank [7], and we were therefore surprised to find that testicular injuries were twice as common in passengers as riders. This suggests that the fuel tank may be a safer structure to decelerate into than the buttocks of a rider sat in front, and warrants a higher index of suspicion for such injuries in motorcycle passengers. However, it is important to draw attention to the limitation of sample size for motorbike passengers which was much smaller than that of riders.

The incidence of bladder injury among cases with pelvic fracture was lower in our motorcyclist cohort than in previous studies including car occupants [9, 10]. It may be that impact with the fuel tank is a strong factor in pelvic fracture, without a seatbelt contributing to rupture of a full bladder.

Urethral injury was rare at 0.2 % overall. This injury is usually identified by signs of urinary retention and blood at the urethral meatus, with “high riding prostate” on rectal examination in rupture of the membranous urethra. Retrograde urethrogram is the gold standard test, and should be performed before catheterisation if urethral injury is suspected. In an unstable patient this may have to be delayed, so a gentle attempt may be made to catheterise and if it fails, a suprapubic catheter inserted [15].

Penile injuries were rare (0.3 % overall, accounting for 4.3 % of GUI), and less common in our cohort than in the French series: Terrier et al. found these to account for 8 % of GUI in motorcyclists, [7] and Paparel et al. in 13 % [6]. This may reflect greater uptake of protective leather clothing in our cooler climate: evidence exists that weather influences its use [16, 17]. Physicians should maintain a high index of suspicion for this rare injury, as it may be easily missed in a tertiary survey, yet the consequences of delayed diagnosis are severe. Early surgical intervention for penile fracture significantly reduces complications such as erectile dysfunction, painful erections and curvature [18]. When suspected, ultrasound may aid in diagnosis, but where this is negative, MRI is the gold standard imaging investigation [19].

The small proportion of riders reported to be wearing body armour is surprising: a 2013 questionnaire found reported use of motorcyclist clothing in 81.4 % of UK riders [17]. It is unclear from the data what “body armour” describes exactly, and we suspect that our data regarding protective clothing are incomplete: this limited our analysis. It should be noted that most motorcyclist clothing sold in the UK contains CE rated (conforming to European Economic Area health and safety requirements) armour. This may be concealed in the elbows, knees and back, and may not be immediately apparent on inspection of the garment in a busy emergency department. Motorcyclist protective clothing has been associated with reduced risk and severity of injury and hospitalisation, even without fitted armour [20] and importantly, protects against soft tissue injury [21].

This is the largest study of GUI among motorcyclists admitted to hospital, and the first to examine injury patterns among riders and passengers separately. Our findings should be generalisable to any UK hospital motorcyclist admissions, and indeed to motorcyclist admissions in comparable contries. The main limitation was the unreliable data on protective clothing, and we have therefore been unable to comment on its effect on GUI patterns.

In summary GUI is common among motorcyclists, most commonly renal trauma. Pelvic fracture is more common in passengers than riders, and although it is a poor predictor for urethral and bladder injuries, they rarely occur in its absence. Given the high incidence of external genital trauma among motorcyclists and the consequences of delayed diagnosis, we recommend that examination of external genitalia be included in the tertiary survey. Further research is needed to explore the protective effects of motorcyclist clothing, and to this end we recommend a review of the way these data are collected for the TARN database.

  1. Statements

8.1. Acknowledgement

The Trauma Audit Research Network (TARN) provided data and support with this study.

8.2. Statement of Ethics

The data for this study came exclusively from the TARN database without author access to patient records. Specific informed patient consent or ethical approval is not required because no patient identifiers are retained by TARN electronically or on paper. The TARN has Patient Information Advisory Group approval.

8.3. Disclosure Statement

The authors have no conflicts of interest to declare.

8.4. Funding Sources

No funding was received

8.5. Author Contributions

Basil Moss conceived of and planned the study, analysed data, drafted and wrote the manuscript.

Catherine Moss provided statistical support and analysis, designed tables and graphics, assisted with writing and approved the final manuscript.

Patrick Dervin assisted with data analysis, reviewed and approved the final manuscript.

Thomas Lawrence assisted with data analysis, provided tables and graphics, reviewed and approved the final manuscript.

Sophie Jones provided data from the TARN database, reviewed and approved the final manuscript.

Stephen Thomas provided supervision, academic critique and guidance, and reviewed and approved the final manuscript.

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  23. Figure Legends

Table 1. Demographics

Table 2. Frequency of GUI amongst motorcycle riders (n=11,924; 94.5% male) and pillion passengers

(n=450; 52.9% male).

Fig. 1. Inclusion criteria STROBE diagram

Fig. 2. Overall distribution (%) of GUI amongst victims (n= 742; 716 male) including riders (black)

and pillions (grey).

Fig. 3. Renal trauma incidence (%) by AAST grade (n=488 kidney injuries amongst 484 victims: 4

bilateral kidney injuries) in riders (black bars) and pillions (grey bars).

By Dr. Carlos Campos, MD, PA On: May 21, 2019 at 11:26:53