Basic testing of an artificial pacemaker in the normal and incontinent anorectum

The role of an artificial pacemaker (AP) in the control of idiopathic fecal incontinence was studied in 15 healthy volunteers (mean age 49.6 years) and 11 patients with idiopathic fecal incontinence (mean age 45.9 years). In the latter, EMG activity of the external anal sphincter (EAS) was diminished, and that of the internal sphincter (IAS) was normal. The pacemaker consisted of a needle, a flat metal piece, a battery and a telegrapher's key. The needle was applied to the IAS and EAS. The rectal and rectal neck pressures were measured by water-perfused tubes, and rectal distension was achieved by a condom-ended catheter. In normal subjects, electric pulsing of either the IAS or EAS caused a significant rectal neck pressure increase (p < 0.01), but insignificant changes in rectal pressure (p > 0.05). Rectal distension with 100 ml of air effected a rectal neck pressure decrease (p < 0.01) and balloon expulsion. IAS pulsing with the rectum distended led to a rectal neck pressure increase (p < 0.001) and rectal pressure decrease (p < 0.0001), but not to balloon expulsion. The rectal neck pressure increased more with EAS pulsing than with IAS pulsing (p < 0.01). In incontinent subjects, IAS pulsing produced a significant rectal neck pressure increase (p < 0.001), while EAS pulsing resulted in an insignificant one (p > 0.05). In the same subjects, IAS pulsing with rectal distension (50 ml air) caused a significant rectal neck pressure increase (p < 0.001) and a significant rectal pressure decrease (p < 0.0001); the rectal balloon was not expelled.(ABSTRACT TRUNCATED AT 250 WORDS)