Ano-vesical reflex: role in inducing micturition in paraplegic patients

The reflex relationship between the anal canal and the urinary bladder was investigated in 14 normal volunteers and in seven patients with spinal cord injury of more than 2 years duration. The latter induced urination by dilating the anal canal with the finger. The vesical pressure was measured by a balloon-tipped catheter introduced into the urinary bladder which was filled with 100 ml saline. The anal canal was inflated with a balloon catheter filled with 2 ml air; inflation was increased in increments of 2 ml up to 10 ml. The vesical pressure in response to both slow and rapid anal distension was recorded. The external and internal anal sphincters were blocked separately and the test was repeated. Rapid anal inflation elevated the vesical pressure. The greater the anal inflation, the higher the vesical pressure. Slow anal distension induced insignificant vesical pressure changes (p > 0.05). Rapid anal distension with internal sphincter block induced insignificant vesical pressure changes (p > 0.05) while the vesical pressure showed a significant increase with external sphincter block. In paraplegic subjects, the vesical pressure increased on rapid anal distension with 6 ml air but did not further increase with greater distension. Vesical pressure increase was recorded after external sphincter block but there was an insignificant change after internal sphincter paralysis. The aforementioned results were reproducible.(ABSTRACT TRUNCATED AT 250 WORDS)