Transcutaneous Electrical Nerve Stimulation Increases Rectal Activity in Children.

Objectives: Neurostimulation is increasingly used in treating bladder and bowel dysfunction, but its effect on rectal motility is obscure. The aim of the study was to evaluate the acute effect of transcutaneous electrical nerve stimulation (TENS) on rectal motility in children with overactive bladder (OAB).
Methods: In this double-blind placebo-controlled study in 20 children with OAB (mean age 8.6 ± 1.8 years; 7 girls), 48-hour urodynamic monitoring including rectal manometry was performed. After 24-hours of baseline investigation without stimulation the children were randomised to either active TENS (n = 10) or placebo (n = 10). Surface electrodes were placed over the sacral bone. The exterior of active and placebo stimulators was identical. Starting in the morning, the children received either continuous TENS stimulation or placebo until bedtime. Rectal contractions were defined as pressure runs exceeding 5 cm H2O and lasting ≥3 minutes.
Results: At baseline there was no significant difference in proportion of time with rectal contractions in the 2 groups (TENS group median 31% [range 12%-66%] vs placebo group median 31% [range 10%-66%]; P = 0.75); however, on the day of stimulation there was more time with rectal contractions in the group receiving TENS (median 51% [range 25%-78%]) compared with placebo (median 32% [range 4%-68%]; P = 0.02). Also, there was an increase in time with rectal contractions in the TENS group (P = 0.007) but not in the placebo group (P = 0.39). The night after the TENS was disabled, rectal activity in both groups returned to baseline level.
Conclusions: TENS acutely increases time with rectal contractions in children undergoing urodynamic investigation. The effect disappears when the stimulator is turned off.