Open AccessDifferences in fatigability of muscles involved in fecal continence: Potential clinical ramifications
Author(s) -
Patel Krupa,
Mei Ling,
Yu Elliot,
Kern Mark,
Lehal Navjit,
Edeani Francis,
Sanvanson Patrick,
Davidson Emily R. W.,
Shaker Reza
Publication year - 2021
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.15144
Subject(s) - anorectal manometry , medicine , fecal incontinence , external anal sphincter , anal canal , urology , high resolution manometry , resistive touchscreen , contraction (grammar) , sphincter , cardiology , anatomy , surgery , defecation , rectum , disease , reflux , electrical engineering , engineering
Fatigue of the anal sphincter complex has been demonstrated using high‐resolution anorectal manometry (HRAM). However, the fatigability of individual muscles such as the external anal sphincter (EAS) and puborectalis muscles (PRM) has not been described. Vaginal manometry has been used to study contractile activity of the PRM. By applying both modalities, we attempted to differentiate the fatigability between the PRM and the EAS under different exercise conditions. Methods We studied two groups: group 1, 12 healthy women (21 ± 2.7 years) with HRAM and group 2, 10 healthy (20 ± 3 years) women with vaginal manometry. All subjects performed 40 repetitive contractions with and without an intra‐anal resistive load. In group 1, areas under the curve (AUC) of the anal canal high‐pressure zone (HPZ) including the caudal and rostral halves were compared. In group 2, the maximum and mean pressures of the vaginal HPZ were compared. Results The AUC decreased significantly only after repetitive contractions against a resistive load (462 ± 129 vs. 390 ± 131 mmHg‐cm, p = 0.02), indicating fatigue. The caudal half (EAS) decreased significantly after contractions against a load (288 ± 75 vs. 239 ± 82 mmHg‐cm, p = 0.02), while the rostral half (PRM) did not. The vaginal pressures (PRM) also decreased only after repetitive contractions against a load (maximum pressures, 358 ± 171 vs. 239 ± 109 mmHg, p = 0.02). Conclusions The EAS and PRM both exhibit fatigue with contractions only against a resistive load. These findings may guide the development of appropriate exercise regimens to target specific muscles involved in fecal continence.