Subclinical microtraumatisation of the scrotal contents in extreme mountain biking

Mountain bikers had a high frequency of extratesticular and testicular disorders, which were associated with clinical symptoms in half the bikers. Hence a high rate of repeated microtraumatisation of the scrotal contents must be assumed.

Since their introduction in the late 1970s, off-road bicycles--commonly known as mountain bikes--have been increasingly popular worldwide. Cyclists are in contact with their bicycles at the pedals, seats, and handlebars, each being associated with particular injuries.[1] Shocks from the rough terrain and vibrations of the saddle cause repeated microtrauma to the perineum, resulting in chafing, perineal folliculitis, furuncles, and subcutaneous perineal nodules.[2] A correlation between biking and alterations of scrotal contents has not yet been reported.

We used high-resolution ultrasonography, which is the method of choice for imaging the scrotal contents,[3] to investigate whether mountain bikers have a higher frequency of extratesticular and testicular disorders. 45 amateur mountain bikers aged between 16 and 44 years (mean 26 years [SD 9.3]) who did a minimum of 2 h per day, 6 days a week of off-road biking were entered into this study. Furthermore, they had covered a distance of more than 5000 km with their mountain bikes annually. All bikers underwent clinical assessment, including a history of pain, discomfort, and scrotal trauma, or inflammation, as well as scrotal inspection and palpation for swelling, tenderness, induration, or other abnormalities. 31 healthy medical students between 15 and 42 years (mean 24 years [SD 8.3]) who had no history of bicycling were also examined. Written informed consent was obtained from the mountain bikers and the healthy volunteers. High-resolution ultrasonography, with an 8.0 MHz linear-array transducer, was undertaken by two radiologists with extensive experience in genitourinary ultrasonography (FF, AK).

43 of 45 bikers (96%) presented with pathological abnormalities of the scrotal contents compared with five of 31 controls (16%; table). On physical examination, 22 bikers (49%), who had pathological findings on ultrasonography, had scrotal tenderness, discomfort, or suspicious findings on palpation, but had no history of severe scrotal trauma or inflammation. One biker presenting with testicular microlithiasis was suspected to have testicular cancer, but testicular biopsy revealed no evidence of cancer. On clinical examination the healthy controls were all without symptoms.

On scrotal ultrasonography, the frequency of scrotal abnormalities in mountain bikers was 43 of 45 (96%) which is unexpectedly high. By comparison, scrotal abnormalities were seen in 29% of men without symptoms and in 40% of andrological patients undergoing routine scrotal ultrasonography.[3] The most common sonographic findings were scrotoliths--ie, non-neoplastic benign calcified masses which can result from haematomas, inflammation of the tunica vaginalis, or from torsion of the appendix testis or epididymis (figure). Such benign extratesticular calcifications often present as painful free-floating or dependent scrotal masses.[4] They could be detected on palpation by the bikers themselves and might raise concerns about testicular cancer, because the frequency of this malignancy between the ages of 20 and 35 years is high. In this clinical setting, ultrasonography allows for accurate diagnosis.

Longitudinal ultrasonogram showing a scrotolith (arrow) in the area of the upper pole of the right testicle in a 28-year-old mountain biker

Testicular microlithiasis has been reported to be a sign of testicular cancer. We found testicular microlithiasis in one biker, but the reported incidence of testicular microlithiasis is similar, hence, extreme mountain biking does not seem to increase the risk of developing testicular microlithiasis.

Spermatoceles were found in about three times as many bikers as controls. Seven of 22 (32%) of these bikers had symptoms whereas there were no symptoms of spermatoceles in the controls. A higher frequency (29%) of spermatoceles was reported in men without symptoms.[3] The high rate of spermatoceles in bikers could also be attributable to repeated microtraumatisation of the epididymis.

Bilateral pudendal nerve injury secondary to excessive biking has been reported to be a saddle-related condition, and if blood supply to the penis is compromised, male erectile dysfunction may develop.[5] We assume that the abnormalities of scrotal contents detected in our study are essentially a saddle-related problem as well, resulting from a higher rate of microtrauma (ie, subclinical traumatisation) to the scrotal contents than previously assumed. The mechanical component responsible for these changes can be reduced by improving the padding of the seat or shorts, adjusting the saddle angle to either horizontal or upward in front, adjusting the saddle height, using an ergonomically designed saddle, and by taking frequent rests during each ride. Furthermore, new shock-absorbent saddles and full suspension bikes might help reduce saddle vibration and microtraumatisation so that mountain biking remains a relatively safe and healthy sport.

Correspondence to: Dr Ferdinand Frauscher (e-mail: ferdinand.frauscher@uibk.ac.at)

Ultrasonographic findings      Controls   Mountain bikers
                               (n=31)     (n=45)

Scrotolith                     0          38 (84%)
Spermatocele                   5 (16%)    22 (49%)
Epididymal calcification       0          20 (44%)
Testicular calcification       0          17 (38%)
Hydrocele                      0          17 (38%)
Varicocele                     0           4 (9%)
Testicular microlithiasis      0           1 (2%)

1 Mellion MB. Common cycling injuries: management and prevention. Sports Med 1991; 11: 52-70.

• 2 Vuong PN Camuzard P, Schoonaert MF. Perineal nodular indurations ("accessory testicles") in cyclists: fine needle aspiration and pathological findings in two cases. Acta Cytol 1988; 32: 86-90.
• 3 Leung ML, Gooding GAW, Williams RD. High-resolution sonography of scrotal contents in asymptomatic subjects. AJR Am J Roentgenol 1984; 143: 161-64.
• 4 Lindowski GD, Avellone A, Gooding GA. Scrotal calculi: sonographic detection. Radiology 1985; 156: 484.
• 5 Ricchiuti VS, Haas CA, Seftel AD, Chelimsky T, Goldstein I. Pudendal nerve injury associated with avid bicycling. J Urol 1999; 162: 2099-100.

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By Ferdinand Frauscher, MD, Department of Radiology II, University Hospital Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria; Andrea Klauser, MD, Department of Radiology II, University Hospital Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria; Alfred Hobisch, MD, Department of Urology, University Hospital Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria; Leo Pallwein, MD, Department of Radiology II, University Hospital Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria and Arnulf Stenzl, MD, Department of Urology, University Hospital Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria

Adapted by MD , MD , MD , MD and MD

This article is copyrighted. All rights reserved. Source: Lancet