Evaluation of the sacroanal motor pathway by magnetic and electric stimulation in patients with fecal incontinence.
OBJECTIVE
The aim of this controlled study was to examine whether it was feasible to use magnetic stimulation as a new diagnostic tool to evaluate the motor function of the sacral roots and the pudendal nerves in patients with fecal incontinence.


METHODS
Nineteen consecutive patients (17 females) with a median age of 67 (range, 36-78) years referred for fecal incontinence and 14 healthy volunteers (six females) with a median age of 42 (range, 23-69) years were examined. Latency times of the motor response of the external anal sphincter were measured after electric transrectal stimulation of the pudendal nerve and magnetic stimulation of the sacral roots.


RESULTS
The success rates of pudendal nerve terminal motor latency and sacral root terminal motor latency measurements were 100 and 85 percent, respectively, in the control group and 94 and 81 percent, respectively, in the fecal incontinence group. Median left pudendal nerve terminal motor latency was 1.88 (range, 1.4-2.9) milliseconds in the control group and 2.3 (range, 1.8-4) milliseconds in the fecal incontinence group (P < 0.006). Median right pudendal nerve terminal motor latency was 1.7 (range, 1.3-3.4) milliseconds in the control group and 2.5 (range, 1.7-6) milliseconds in the fecal incontinence group (P < 0.003). Median left sacral root terminal motor latency was 3.3 (range, 2.1-6) milliseconds in the control group and 3.7 (range, 2.8-4.8) milliseconds in the fecal incontinence group (P < 0.03). Median right sacral root terminal motor latency was 3 (range, 2.6-5.8) milliseconds in the control group and 3.9 (range, 2.5-7.2) milliseconds in the fecal incontinence group (P = 0.15).


CONCLUSIONS
Combined pudendal nerve terminal motor latency and sacral root terminal motor latency measurements may allow us to study both proximal and distal pudendal nerve motor function in patients with fecal incontinence. Values of sacral root terminal motor latency have to be interpreted cautiously because of the uncertainty about the exact site of magnetic stimulation and the limited magnetic field strength.
Department of Colorectal Surgery, University Hospital Linköping, Sweden.
G L
GL
Morren
S
S
Walter
H
H
Lindehammar
O
O
Hallböök
R
R
Sjödahl
D000328:Adult; D000368:Aged; D001003:Anal Canal / Q000294:innervation*; D004558:Electric Stimulation; D005240:Feasibility Studies; D005242:Fecal Incontinence / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008160:Lumbosacral Plexus / Q000503:physiopathology*; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction; D011930:Reaction Time; D013126:Spinal Nerve Roots / Q000503:physiopathology*