Only the Nose Knows: Penile Hemodynamic Study of the Perineum–Saddle Interface in Men with Erectile Dysfunction Utilizing Bicycle Saddles and Seats with and without Nose Extensions

ABSTRACT

Purpose

To investigate the differential impact of straddles (A_ns and B_ns) and noseless two‐cheek seats (A_ntcs and B_ntcs) on penile hemodynamics and perineal compressive forces in subjects who cycle in a stationary bicycle.

Materials and Methods

Subjects underwent cavernosal artery peak systolic velocity (CAPSV) measurements after intracavernosal injection of vasoactive agents while supine, sitting upright on an examination table, straddling a saddle, sitting on a seat, and again supine. Mean perineal compression pressures recorded while straddling the saddles were compared with those while sitting upright.

Results

No differences were found in right and left CAPSV values while supine, sitting upright on an examination table, sitting on a seat, and supine again. Right/left CAPSV (cm/second) values straddling A_ns and saddle B_ns (0.7 ± 2.9/1.5 ± 6.2 and 0/0, respectively) were significantly lower than values obtained while sitting on A_ntcs and B_ntcs (25.6 ± 13.4/23.8 ± 12.0 and 17.3 ± 6.4/18.3 ± 6.5, respectively) (P < 0.001). Mean perineal compression pressures (mm Hg) on A_ns and saddle B_ns (315.2 ± 39 and 387.9 ± 64.3, respectively) were significantly higher than values obtained while sitting upright on an examination table (47.6 ± 5.2 and 46.0 ± 8.1, respectively) (P < 0.001).

Conclusions

e have identified an objective test to assess if an individual bicycle rider, sitting on a certain shape of bicycle saddle or seat generates sufficient compressive forces at the perineal–saddle interface to obstruct cavernosal arterial inflow. This study also demonstrated that straddling bicycle saddles with nose extensions is associated with perineum–saddle interface compressive pressures that exceed systolic perfusion pressures, significantly diminishing penile hemodynamics. Munarriz R, Huang V, Uberoi J, Maitland S, Payton T, and Goldstein I. Only the nose knows: Penile hemodynamic study of the perineum–saddle interface in men with erectile dysfunction utilizing bicycle saddles and seats with and without nose extensions. J Sex Med 2005;2:612–619.

Introduction

Bicycle riding is a widespread, environmentally friendly, and popular mode of transportation used by 53.7 million people in the United States in 2003, according to Sporting Goods Manufacturers Association [1]. Health benefits include cardiovascular health, weight loss, relaxation, and improved quality of life. Aerobic exercise (energy expenditure of 7.5 kcal/minute) from cycling can halve the risk of coronary heart disease when compared with men who lack cardiovascular exercise [2]. On the other hand, bicycle riding is also associated with health risks, including neurologic and orthopedic disorders of the neck, back, hand, and knee as well as erectile dysfunction (ED) [3, 4].

The relationship between the health risk of bicycle riding and ED has been described in case reports [5, 6, 7], observational series [4, 8], case control studies [9], and population‐based epidemiologic investigations [10]. A recent population‐based epidemiologic study examined 1,706 free‐living men, including various types of bicyclists and men who rode for a broad range of activities. Bicycle riding more than 3 hours per week was an independent risk factor (odds ratio 1.72) for ED [10].

To better understand the association between riding on a bicycle saddle and ED, several investigations have examined the role of compression at the perineal–saddle interface. A saddle is defined here as a narrow device with a nose, which the rider straddles, thereby bearing body weight on the ischio‐pubic rami [11, 12, 13]. Kerstein et al. reported that after straddling a saddle, the flaccid‐based penile brachial index value declined to 0.62 in the supine position [14]. Other studies have also shown a reduction of 40–50 mm Hg in penile blood pressure when bicycling in a straddling position compared with bicycling in a standing position [11, 14]. Several researchers have suggested that different bicycle saddles or seats have varying abilities to adversely influence penile hemodynamics. A seat is defined here as a wide device with or without a nose, on which the rider sits, thereby bearing body weight on the ischial tuberosities. Schwarzer et al. reported a 70% average reduction in penile artery blood flow when subjects cycled on a bike saddle, while only 22% reduction in blood flow measured with a bicycle seat [13]. Schrader et al. concluded that prolonged bicycle riding had negatively impacted nocturnal erectile function of bicycle‐riding policemen compared with nonbicycle riders and that the abnormal perineal pressures exerted by bicycle saddles indicated an occupational safety concern [15].

In summary, data are accumulating that excessive perineal pressure adversely affects penile blood flow and erectile function. As a result, new ergonometric bicycle saddles or seats are being developed to protect the rider from compression injury to critical perineal structures that could result in ED. One of the newest bicycle seat designs is the split, two‐cheek seat without a nose extension (Figure 1B,D), in which, the rider is forced to bear body weight on the ischial tuberosities instead of the perineum. For the purpose of this study, the nose of a bicycle saddle is defined by the pointed, rounded front‐end extension of varying length, width, and shape. In general, the nose of a bicycle saddle is thought to provide the rider with control, support, balance, and steering efficiency. The aim of this study was to investigate the differential impact of straddles (A_ns and B_ns) and noseless two‐cheek seats (A_ntcs and B_ntcs) on penile hemodynamics and perineal compressive forces in subjects who cycle in a stationary bicycle.