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27 Effect of Sacral Nerve Stimulation in Patients with Fecal and Urinary Incontinence [2001년 6월 DCR] 2011-11-17 3162
 
Anne-Marie Leroi, Ph.D., F. Michot, Ph.D., P. Grise, Ph.D.,J- P. Denis, Ph.D.
 
From the Groupe de Recherche de l'Appareil Digestif, Environnement et Nutrition, and Service 'Urologie,
Centre Hospitalier R~gional el Universitaire de Rouen, Rouen, France
 
PURPOSE: Preliminary studies have shown improvement in fecal incontinence in several patients who received temporary or permanent stimulation. The purpose of this study was to report our experience in sacral nerve stimulation in the treatment of fecal incontinence and to target patients who would benefit most fi'om stimulation.
METHODS: Patients with fecal incontinence were studied clinically and manometrically before, during, and after temporary nerve stimulation. If temporary nerve stimulation was clinically successful, the patient was implanted and followed up for six months.
RESULTS: Nine patients (6 female) with a mean age of 50.7 + 12.3 years underwent temporary nerve stimulation. Temporary nerve stimulation was successful in eight patients, six of whom were implanted. Of the patients who could be evaluated, three of five had improved at the six-month follow-up visit, particularly in relation to the number of urgency episodes and delay in postponing defecation. All implanted patients had urinary symptoms. Urinary urgency was also improved by stimulation. During
temporary nerve stimulation, the maximal squeeze pressure amplitude increased. After implantation, only the duration of maximal squeeze pressure seemed to improve.
CONCLUSION: Sacral nerve stimulation can be used in the management of fecal incontinence, particularly in cases of urge fecal incontinence associated with urinary urgency. This study seems to confirm the effect of sacral nerve stimulation on striated sphincter function.
 
Electrical stimulation of the sacral spinal nerves was first described as a treatment option for patients
with refractory urinary urge incontinence and detrusor instability. Sacral nerve stimulation might also be effective for fecal incontinence. Vaizey et al. showed that temporary sacral nerve stimulation improved
fecal incontinence in nine patients. However, only two preliminary studies reported the effectiveness
of permanent electrical stimulation of the sacral spinal nerves for the treatment of fecal incontinence.
Overall, only eight patients have been evaluated over a period of 64 to 16 months.
 
Because results concerning this new technique for the treatment of fecal incontinence are still limited, we report the effect of temporary and permanent nerve stimulation on pelvic floor function in nine patients
with fecal incontinence.
 
DISCUSSION
This study is a short trial of sacral nerve stimulation in nine patients with fecal incontinence, six of whom were implanted and five who were followed for six months. At three months, fecal incontinence had improved in the six implanted patients and five of six patients were satisfied with the results. Three of five patients had improved fecal continence and were satisfied with their results at six months. Despite the slight deterioration in the beneficial effect of sacral nerve stimulation over time, our results confirm previous studies showing that permanent sacral nerve stimulation is a promising treatment of fecal incontinence, tn these patients, the only remaining therapeutic alternative was an artificial anal sphincter or electrostimulated graciloplasty, both of which are more invasive than chronic neuromodulation.
 
The physiologic explanation for the effectiveness of sacral nerve stimulation in fecal incontinence is still
unclear. As in previous studies which have already emphasized the discrepancy between clinical results and urodynamic findings, the present study showed that symptomatic improvement did not always correspond to objective manometric parameters, Although this discrepancy could, suggest that
nerve stimulation is associated with a placebo effect, there are two arguments against this hypothesis: 1) the long-lasting effectiveness of the treatment (six months) in some patients and 2) the example of
Patient 4 who consulted again after the three-month visit because of recurrence of incontinence. The scan showed that the electrode was no longer in place, thus explaining the recurrence of symptoms. Another explanation for this discrepancy could be that anorectal manometry and the saline continence test are not the most reliable instruments to record the therapeutic effects of sacral nerve stimulation.
 
In confirmation of other studies, this study showed that stimulation had a significant effect on sphincter function. There was an increase in the maximum anal squeeze pressure during TNS. At the same
time, the average number of urgency episodes decreased and the delay for postponing defecation increased. However, after three months of permanent stimulation, the present study did not confirm the
results of Matzel et al. who observed an increase in squeeze pressure as stimulation increased. In our
study, the mean squeeze pressure was not different from that before stimulation, in contrast to a persistent improvement in delay to postpone defecation and in the number of urgency episodes. The deterioration over time of the amplitude of voluntary contractions may be because of muscle fatigue from continuous electrical stimulation. Another explanation is the transformation of fast-twitch type II to slow-twitch type I muscle fibers. After three months of stimulation, the duration of voluntary contractions seems to have improved compared with before stimulation. An increase in the duration of voluntary contractions has already been described after anal electrostimulation in patients with fecal incontinence.
An increase in the duration associated with a decrease in the amplitude of voluntary contractions of the anal sphincter could be because of a change in muscle phenotype. However, this controversial hypothesis needs to be confirmed by physiologic or histochemical data.
 
Until now, the only way to define suitable candidates for permanent sacral nerve stimulation has been
from the clinical results of TNS. However, more than 25 percent of the patients with lower urinary tract
dysfunction who respond well to the percutaneous trial fail to respond to the permanent implant. In our study, two of six of the implanted patients with good clinical response to TNS who were evaluated
were not satisfied after six months of permanent stimulation. One explanation of overestimation of improvement from TNS by the implantation candidates might be the placebo effect. However, the significant improvement in manometric parameters during TNS does not support this hypothesis. Short-term stimulation and long-term stimulation might improve fecal incontinence by different neuronal mechanisms.
 
Patients who could benefit from sacral nerve stimulation have not been clearly defined. We performed
TNS in a nonhomogeneous group of patients because it is recommended that new technologies be assessed in patients under different conditions to define possible uses. Urge incontinence is associated with the impairment of striated musculature of the anal sphincter comptex. Because sacral nerve stimulation improved external anal sphincter function, patients with urge fecal incontinence should be good candidates for this treatment. In the present study-, the number of fecal urgency episodes and the delay in postponing defecation improved during sacral nerve stimulation. However, the two patients who were not successfully treated by sacral nerve stimulation had urge fecal incontinence, and the patient with only passive fecal incontinence was cured by sacral nerve stimulation. Because of these results and the limited number of patients studied, no firm conclusions can be drawn from these results.
 
The association of fecal incontinence and urge urinary incontinence because of detrusor instability is far
from anecdotal. Because continuous stimulation of the sacral nerves has been used to treat patients with bladder dysfunction for several years, we evaluated the results of this technique in the treatment of
double fecal and urinary incontinence. Unlike previous studies, our results showed that stress urinary
incontinence relapsed in all patients after implantation. However, sacral nerve stimulation had a beneficial effect on urgency and urge urinary incontinence. Sacral nerve stimulation might be a good treatment option for patients with double incontinence, especially if they have urgency symptoms.
 
Although the mode of action of sacral nerve stimulation has not been clarified, marked results can be
obtained in patients with fecal incontinence who fail to respond to traditional treatment options, particularly in cases of urge fecal incontinence associated with urinary urgency. This new technology will certainly become a valuable addition to our treatment options in these difficult patients.