Related Experiment Video
Updated: Jul 7, 2026
Urethral Stricture Induction Followed by Buccal Mucosa Graft Urethroplasty in a Rat Model
Published on: April 28, 2023
Effect of prolonged vaginal distention and sphincter transection on physiologic function of the external anal
Clifford Y Wai1, Rodney T Miller, R Ann Word
1Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9032, USA. Clifford.Wai@UTSouthwestern.edu
Objective:
To estimate the effect of prolonged vaginal distention and anal sphincter transection on contractile properties of the external anal sphincter.
Methods:
Young female virgin rats were randomly assigned to four treatment groups (sham, vaginal distention, transection of anal sphincter plus repair, or combined distention and transection plus repair). After 3 weeks, the anal sphincter complex was analyzed for twitch tension, maximal tetanic force, fatigue, and maximal responses to electrical field stimulation. Each sphincter was serially cross-sectioned and stained with hematoxylin and eosin to evaluate sphincter integrity. Statistical evaluation was performed using analysis of variance (Student-Newman-Keuls) and chi2 analysis.
Results:
The function of a transected and repaired anal sphincter is compromised significantly after 3 weeks. Vaginal distention alone did not alter function of the sphincter. Further, prolonged vaginal distention together with sphincter transection did not result in statistically significant differences in sphincter function compared with transection alone.
Conclusion:
In an animal model, there is a major effect on external anal sphincter function in vitro 3 weeks after laceration with repair. Although prolonged vaginal distention had no significant effect alone and minimal adverse effects on the lacerated anal sphincter, laceration of the sphincter has major adverse effects on its morphology and function.
Level Of Evidence:
II.
