The Guarding Reflex Anal, Study of the Modulation Function of Rectal Distension

Difference in curve slope between empty rectum and maximal tolerable volume at cough

The term Guarding Reflex refers to a progressive, involuntary increase in the external
 urethral sphincter activity during bladder filling.This is a mechanism of continence,
 preventing from unwanted urine leakage in situation of stress.
 
 Anal continence is essential, and any impairment of this function can have a severe impact on
 quality of life. Anal continence at rest is mainly insured by the tone of the internal anal
 sphincter. The external anal sphincter activity during gradually rectal filling is continuous
 and varies according to the volume of rectal distension.
 
 During an effort, or a cough, the increasing intra-abdominal pressure is transmitted to the
 rectum. Increased intra-abdominal pressure during an expiratory against resistance effort
 proportionally increases the response of the external anal sphincter. The reflex contraction
 of the EAS is an active mechanism under spinal control, and result in a stronger contraction
 than a voluntary one. This reflex contraction is the equivalent of Guarding Reflex and
 provides part of the continence in situation of stress.
 
 The main purpose of this study is to research a correlation between the ano rectal distension
 volume and the external anal sphincter response to a stress.
 
 Patient over eighteen years old, consulting for anorectal manometry examination in order to
 explore anorectal disorders are included.
 
 Age, sex, ano rectal symptoms, treatments, past history, manometrics data, area under the
 curve for electromyography activity of the EAS and intercostal muscles during cough with a
 Valsalva effort are recorded. Slope curve representing the EAS response to stress according
 to the intercostal activity reflecting cough (intensity response curve) effort are
 calculated.
 
 The protocol consists in distending the rectum at four different volumes. For each volume,
 the patient is asked to cough three times gradually, and perform a Valsalva effort three
 times gradually.
 
 Primary outcome is the difference in curve slope (intensity response curves) between empty
 rectum and maximal tolerable volume at cough Secondary outcomes are the differences in curve
 slope between each volume of distension at cough, and Valsalva type effort.