Effect of aging on anorectal and pelvic floor functions in females

PURPOSE: In females, fecal incontinence often is attributed to birth trauma; however, symptoms sometimes begin decades after delivery, suggesting that anorectal sensorimotor functions decline with aging. METHODS: In 61 asymptomatic females (age, 44 ± 2 years, mean ± standard error of the mean) without risk factors for anorectal trauma, anal pressures, rectal compliance, and sensation were assessed by manometry, staircase balloon distention, and a visual analog scale during phasic distentions respectively. Anal sphincter appearance and pelvic floor motion also were assessed by static and dynamic magnetic resonance imaging respectively in 38 of 61 females. RESULTS: Aging was associated with lower anal resting (r = -0.44, P < 0.001) and squeeze pressures (r = -0.32, P = 0.01), reduced rectal compliance (i.e., r for pressure at half-maximum volume vs. age = 0.4, P = 0.001), and lower (P ≤ 0.002) visual analog scale scores during phasic distentions at 16 (r = -0.5) and 24 mmHg (r = -0.4). Magnetic resonance imaging revealed normal anal sphincters in 29 females and significant sphincter injury, not associated with aging, in 9 females. The location of the anorectal junction at rest (r = 0.52, P < 0.001), squeeze (r = 0.62, P < 0.001), and Valsalva maneuver (r = 0.35, P = 0.03), but not anorectal motion (e.g., from resting to squeeze) was associated with age. CONCLUSIONS: In asymptomatic females, aging is associated with reduced anal resting and squeeze pressures, reduced rectal compliance, reduced rectal sensation, and perineal laxity. Together, these changes may predispose to fecal incontinence in elderly females.