Suppression of Uninhibited Rectal Detrusor by Functional Magnetic Stimulation of Sacral Root

Abstract

Purpose. To demonstrate the effect of sacral magnetic stimulation (MS) on the uninhibited rectal detrusor aiming at suppression of unstable rectal contractions.Methods. The study was comprised of 6 patients (3 women, 3 men, ages between 32 and 49 years) with supracanal spinal cord injury who complained of fecal incontinence. Rectal sensation for defecation was felt after the onset of involuntary detrusor contraction in 4 patients and not perceived in 2. Rectal and rectal neck pressures were normal. Rectal hyperreflexia was provoked by rapid saline infusion into the rectum (1 00 to 150 ml; 15 ml/s). Sacral MS was effected by a magnetic coil and a stimulator. The coil was applied to the back between L-4 and L-5.Results. During the provocative saline test, the rectal pressure showed a significant increase (p < .001) and the subjects evacuated the infused saline involuntarily; the rectal neck pressure showed no significant change (p > .05). Intermittent MS during the induced rectal pressure rise using 70% of maximal intensity (i.e., 175 Joules per pulse, 40 Hz frequency, and 2 second burst length with 2 seconds off) affected rectal pressure decline (p < .01) and no saline evacuation.Conclusions. Sacral MS produced inhibition of provoked rectal hyperreflex contractions in patients with supraconal cord injuries. The method is simple, easy, noninvasive, and with no adverse effects.