Ash. Chen et al., PUDENDAL NERVE LATENCY - DOES IT PREDICT OUTCOME OF ANAL-SPHINCTER REPAIR, Diseases of the colon & rectum, 41(8), 1998, pp. 1005-1009
PURPOSE: Electrophysiologic evaluation has been suggested as a means o
f identifying prognostic factors for patients with fecal incontinence
who undergo anal sphincter repair. The purpose of this study was to ev
aluate the results of anal sphincter repair in patients with documente
d pudendal neuropathy and to determine the usefulness of electrophysio
logic studies for prognostication of sphincteroplasty. METHODS: A retr
ospective review of a series of patients undergoing electrophysiologic
studies and anterior anal sphincteroplasty was performed. Data collec
ted included age, standardized incontinence scores (preoperative, imme
diately postoperative, and current follow-up), and results of pudendal
nerve terminal motor latency and monopolar electromyography. Outcomes
of sphinctero plasty were designated as excellent, good, fair, or poo
r based on incontinence scores. Prolonged pudendal nerve terminal moto
r latency was defined as longer than 2.2 ms and evaluated as unilatera
l of bilateral. RESULTS: During the time period of the study (1991-199
6), 15 patients had electrophysiologic studies and underwent sphincter
oplasty. Twelve patients (80 percent) were available for follow-up and
form the basis for this study. All patients were women, with a mean a
ge of 45 +/- 18.6 (27-75) pears and a mean follow-up of 49.7 +/- 18.6
(20.4-72.6) months. Mean duration of incontinence preoperatively was 1
3 +/- 16.1 (range, 1-58) years. The incontinence score was 15.8 +/- 3.
5 preoperatively, 5.4 +/- 4.5 postoperatively, and 5 + 5.1 currently f
or all 12 patients. There was one patient with normal pudendal nerve t
erminal motor latency. In the four patients with bilateral prolonged p
udendal nerve terminal motor latency, the incontinence scores were 15
+/- 4.2 preoperatively, 8.5 +/- 5.3 postoperatively, and 6 +/- 6.1 (st
atistically significant compared with preoperation) currently. Seven p
atients were found to have unilateral prolonged pudendal nerve termina
l motor latency with incontinence scores of 16.3 +/- 3.5 preoperativel
y, 4.4 +/- 3.2 (statistically significant compared with preoperation)
postoperatively, and 5.1 +/- 4.9 (statistically significant compared w
ith preoperation) currently. Based on incontinence scores, results of
the sphincteroplasty at the most current followup were as follows: no
neuropathy, excellent in one patient; unilateral neuropathy, five with
good/excellent results, two with fair/poor results; bilateral neuropa
thy, two with good/excellent results, two with fair/poor results (P >
0.05 bilateral vs. unilateral). By monopolar electromyographic examina
tion, external anal sphincter denervation was noted in 11 patients; th
eir incontinence scores were 15.5 +/- 3.5 preoper atively, 5.9 +/- 4.3
(statistically significant compared with preoperation) postoperativel
y, and 5.5 +/- 5.0 (statistically significant compared with preoperati
on) currently. Monopolar electromyographic results in the puborectalis
included four normal examinations and six that were unobtainable. In
the two patients with puborectalis denervation, the incontinence score
s were 19.5 +/- 0.7 preoperatively, 8.5 +/- 4.9 postoperatively, and 2
.5 +/- 3.5 (statistically significant compared with preoperation) curr
ently. CONCLUSIONS: Anterior anal sphincteroplasty in patients with un
ilateral or bilateral prolonged pudendal nerve terminal motor latency
can provide significant improvement in continence with minimum morbidi
ty. Therefore, correction of the anatomic sphincter defect should stil
l be considered, even in patients with documented pudendal neuropathy.