- Email: [email protected]
Sacral neuromodulation in the treatment of severe anal incontinence
© Masson, Paris, 2006.
Gastroenterol Clin Biol 2006;30:669-672
Sacral neuromodulation in the treatment of severe anal incontinence ORIGINAL ARTICLE
Forty consecutive cases treated in one institution Jean-Luc FAUCHERON (1), Richard BOST (2), Virginie DUFFOURNET (3), Simon DUPUY (1), Nicolas CARDIN (1), Bruno BONAZ (2)
(1) Unité de Chirurgie Colorectale, Département de Chirurgie Digestive et de l’Urgence, (2) Département d’Hépatogastroentérologie, Hôpital Albert Michallon, Grenoble ; (3) Service de Médecine, Centre Hospitalier d’Annecy.
SUMMARY
RÉSUMÉ
Introduction — Sacral neuromodulation is a recognized therapeutic option in severe anal incontinence from neurogenic origins, when medical treatment has failed.
La neuromodulation sacrée dans le traitement de l’incontinence anale sévère : à propos de 40 cas consécutifs traités dans une seule institution
Methods — We report the results of this procedure applied in 40 consecutive patients operated on by a single surgeon from August 2001 to June 2004. Mean duration of incontinence was 5 years. There were 33 women and 7 men of mean age 59 (range 29-89). All patients had had medical treatment, 26 had had physiotherapy and 9 had been previously operated on for that problem. Neuromodulation consisted in a temporary electrical stimulation test followed by implantation of a stimulator in case of efficacy.
Jean-Luc FAUCHERON, Richard BOST, Virginie DUFFOURNET, Simon DUPUY, Nicolas CARDIN, Bruno BONAZ
(Gastroenterol Clin Biol 2006;30:669-672)
Introduction — La neuromodulation peut être proposée dans le traitement d’une incontinence anale sévère d’origine neurogène ou idiopathique, lorsque le traitement médical a échoué. Méthodes — Nous rapportons les résultats de ce traitement chez 40 malades consécutifs traités par le même chirurgien entre août 2001 et juin 2004. La durée moyenne de l’incontinence était de 5 ans. Il s’agissait de 33 femmes et 7 hommes, d’une moyenne d’âge de 59 ans (29-89). Tous les malades avaient eu un traitement médical, 26 une rééducation et 9 une intervention chirurgicale. La neuromodulation consistait en un test temporaire de stimulation sacrée, suivi en cas d’efficacité par l’implantation définitive d’un neurostimulateur.
Results — Twenty nine patients had a positive test and were implanted. Ten had a negative test and one is waiting for implantation. From the 29 patients, 23 had uneventful postoperative course. Incontinence score varied from 17 before neuromodulation to 6 after in the 24 patients who were improved. Mean resting pressure, mean maximum squeeze pressure and mean duration of squeeze pressure did not change from pre to postoperative period.
Résultats — Vingt-neuf des 40 malades ont eu un test positif, qui a conduit à l’implantation définitive. Parmi les 11 autres malades, 10 ont eu un échec de la stimulation externe et le onzième attend l’implantation. Parmi les 29 malades, 23 ont eu des suites simples. L’incontinence anale, jugée sur le score de Vaizey, est passée de 17 à 6 après l’implantation chez les 24 malades ayant eu une amélioration. La pression moyenne de repos chez ces malades est passée de 57 à 46 cm d’eau (NS) et la pression moyenne de contraction de 92 à 84 cm d’eau (NS). La durée moyenne de contraction volontaire est passée de 19 à 18 secondes (NS).
Conclusion — Sacral neuromodulation is a safe and efficacious procedure in properly selected anal incontinent patients. However, we observed no correlation between clinical and manometric data.
Conclusions — La neuromodulation est une technique sûre et efficace chez les malades incontinents sélectionnés. Cependant, il ne semble pas y avoir de corrélation entre les résultats cliniques et les résultats manométriques.
types of effort induced urinary incontinence and certain dysurias [6]. The efficacy of this technique on anal incontinence was discovered nearly fortuitously in patients treated for urinary incontinence who showed improvement of their associated digestive symptoms [7]. As a result neuromodulation was proposed in 1995 in the treatment of anal incontinence alone [5]. We report the surgical and functional results of this treatment in 40 consecutive patients with severe anal incontinence who did not respond to other techniques.
Introduction Surgical treatment of anal incontinence includes direct repair of the sphincter in case of rupture [1, 2], substitution of the sphincter by muscle plasty which may be dynamic [3] implantation of an artificial sphincter when the sphincter cannot be repaired, [4] and for the last ten years or so, sacral neuromodulation, which is mainly indicated in anal incontinence from neurogenic causes [5]. The first implantations of a stimulator for sacral nerve neuromodulation were performed in 1981 for the treatment of certain
Patients and methods
Reprints: J.L. FAUCHERON, Unité de Chirurgie Colorectale, Département de Chirurgie Digestive et de l’Urgence, BP 217, 38043 Grenoble. E-mail : [email protected]
From August 2001 to June 2004, 40 patients including 33 women, an average of 59 years old (range 29-89) underwent a test period of sacral nerve stimulation for severe anal incontinence that had lasted for an average of at least 5 years (range 1-31 years). All patients had
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tocks using a 10 cm extension cord. The stimulator is programmed by the operator, thanks to a percutaneous telemetric programmer. The following parameters can be modified: amplitude (1-10 volts), frequency (around 15 Hz for this indication), duration of the impulse (approximately 210 microseconds for this indication) as well as the charge of the four contacts of the electrode and the case (neutral, positive or negative). The programmer also makes it possible to know the impedance of the system (in ohms), the percentage of use of the stimulator and the estimated life of the battery. The patient has a simple remote control case which allows him to change the amplitude within the range determined by the operator and to stop stimulation (which is not pertinent for an indication of sacral nerve stimulation). Each patient undergoes a check-up before the first intervention including a clinical examination and questions to determine the Vaizey score [8], pelvic examination, endoanal ultrasound, anorectal manometry and an electromyogram. Other examinations may be performed if necessary: dynamic colpocystodefecography (to eliminate the presence of a static or dynamic pelvis) [9], a colonoscopy (in case of rectal bleeding, transit problems or a family history of cancer), colon transit time (to differentiate transit constipation from dyschesia, for example), sacral X ray (if a traumatic, tumoral or other bone lesion is suspected), pelvic Tomodensitometry, MRI, or an MRI of the medullary canal (if a medullary lesion is suspected. These examinations can then lead to more sophisticated tests (EMG of the lower limbs, if neurological disease is suspected for example). After the second operation, all the patients were seen at 1, 3, 6, 12, 18 and 24 months. Besides a clinical examination to establish the Vaizey score, manometry was obtained during the 3rd and 6th months. If electrode displacement was suspected, three dimensional sacral TDM was performed.
already received medical treatment associated with a diet and 26 had received biofeedback training. Nine of the patients had already undergone surgery for anal incontinence: five had had direct reparation (two requiring more than one intervention) that had been effective from a morphological standpoint, and four underwent dynamic muscle plasty before neuromodulation came into use. The cause of anal incontinence is summarized in table I.
Methods Neuromodulation includes two surgical steps which can be performed under general or local anesthesia. The first step involves implantation of a finned electrode into the 3rd or 4th right or left sacral roots, with the patient in the decubitus ventral position, their feet off the table with the perianal region in the operating field. The correct positioning of the electrode is defined clinically and by an X-ray of the profile under a brilliance amplifier. Clinically, successive stimulation of the 4 contacts of the electrode by an external electric stimulator administering 1 to 10 volts should cause a sensation in the perinium which is difficult to describe (and which is obviously absent under general anesthesia), an anal contraction associating closure and ascension of the anus by stimulation of the external sphincter and the elevator muscles of the anus (under general anesthesia, curare should not be used) as well as irregular flexing of the toes. The X-ray helps confirm the exact position of the electrode; position, depth and direction. In practice the fins help prevent migration of the electrode, stimulation is first administered through a hollow needle, then replaced by the electrode thanks to a kit based on the Seldinger technique. The implanted electrode is then attached to an extension, connected to the external stimulator and emerging from the supero-external quadrant of the controlateral buttock. The patient is then rapidly and easily trained to use the external stimulator at home and during all normal activities. The patient must wear the stimulator night and day on his waist, increasing the voltage to maximum and leaving the frequency around 10 Hz. A detailed record of all stools must be noted, in the same way the patient did before the intervention: frequency of transit, frequency and importance of leaking, the level of urgency of stools; a space is left for comments, which can provide important information (it is not unusual to learn that transit has normalized, stools have become harder and any associated urinary leaking has disappeared, or that the sex drive increases). The patient is seen 8 to 15 days later (depending on the availability of the patient and the physician) and the record of stools is studied by the surgeon: if the number of leaks is reduced by at least 50%, and the patient has not modified his lifestyle, diet, or taken any medication that slows transit, the test is considered positive and permanent implantation of a stimulator is suggested (MEDTRONIC 3023) during a second intervention. The second surgical intervention is performed with the patient in the decubitus ventral position, but this time, the feet can be placed on the table and the anus isolated in the surgical field. The incision at the level of the electrode and the extension is enlarged and the electrode is attached to a MEDTRONIC 3023 neurostimulator, placed in a subcutaneous muscle chamber of the superoexternal quadrant of the homolateral but-
Statistical Analyses All the quantitative data were compared using the Wilcoxon test.
Results Surgical results None of the patients were lost to follow up. Twenty nine of the 40 patients tested for severe anal incontinence had implantation of a neurostimulator. There were no deaths. After the first intervention, there was no morbidity in any of the 40 patients. Most complications occurred after the second intervention. Infection at the remote control site resulted in removal of the implant in two cases; in one obese patient with diabetes that had not been stabilized; despite the infection, the patient insisted on keeping the stimulator for 9 months because it was effective. The surgeon convinced her to remove the implant, and a new implant was successfully put in place 11 months later. In the second patient there was a simple erythema at the exit spot of the extension cord at the time of implantation, while a bacteriological skin sample was negative for any aggressive germ and the dermatologist was not against the procedure. The site became infected several days later, the muscle chamber of the remote control case was washed and eventually the implant was removed. In a third patient, due to a persistent seroma a simple needle aspiration was performed with sterile results during the first month follow up visit. A fourth patient experienced pain at the remote control site. This patient was a high level sportsman, who was very muscular, so the location of the stimulator was changed. In the fifth case, sudden worsening of the functional results (recurrence of anal incontinence) associated with a sensation of electrical discharge and burning in the buttocks when the amplitude was increased, confirmed diagnosis of a displaced electrode. This complication was confirmed by TDM and a new electrode was successfully implanted under general anesthesia. The cause of displacement was not identified. The last complication in a sixth patient occurred when the neurostimulator lost its charge prematurely, so that it had to be replaced along with a
Table I. – Causes of anal incontinence. Etiologie de l’incontinence anale. Cause
N
Pudendal neuropathy
16
Idiopathic incontinence *
7
Cauda equina syndrome
5
Peripheral neuropathy
3
Sphincter repair
3
Other **
6
Total
40
* Incontinence was considered idiopathic when there was no identified organic cause and the EMG did not show any increase in the distal latency of the pudendal nerve. ** Radiation and postoperative fibrosis: 2; rectopexy: 1; stroke: 1; sacral resection : 1 and traumatic medullary lesion : 1.
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new electrode, 3 years and five months after the first implantation. This may be because the configuration of the parameters of the four electrode contacts were not optimal — the electrode was not in a good position — so that an elevated amplitude (more than 3 volts at all times, and up to 8 volts) was necessary for effective neurostimulation.
when the electrode was functioning and correctly placed. The eleventh patient is waiting for implantation. The alleged clinical improvement of 24 patients based on the Vaizey score was not accompanied by improvement in manometric paramenters (table II). The average resting pressure, the average pressure during voluntary squeezing and the average duration of this contraction were even lower after implantation of the stimulator than before the test.
Functional results Anal incontinence improved in twenty four of the 29 implanted patients at the sixth month of follow up. In these patients, the Vaisey score went from an average of 17/24 before the test to 6/24, six months after implantation of the stimulator. Details for each patient are found in figure 1. Of the 11 patients who underwent the test but who were not implanted, the indication was considered inappropriate in 5 cases a posteriori. The first patient had become incontinent after undergoing radiotherapy and a proctetomy followed by a coloanal anastomosis complicated by suppuration. The second patient presented with moderate anal incontinence from a pudendal neuropathy associated with perineoanal-buttocks pain which was not relieved. The third patient was 89 years old, with anal soiling cause by severe dyschezia with the development of scatomas requiring laxatives. Besides anal incontinence, the fourth patient had numerous sequellae from a rectopexy by laparotomy for rectal prolapsus, performed in another institution. The fifth patient had anal incontinence with radiation induced rectitis. These five cases were among the first 20 patients. Five other patients who underwent an external neurostimulation test were considered to be real failures, because there was no reduction in the number of anal leakages or less than 50% reduction in the number of anal leaks
Discussion The indications for neuromodulation were recently described in a review of the literature performed by Jarret et al. [10]. In this same paper the authors identified 106 articles on the subject of sacral neuromodulation for the treatment of anal incontinence. When only those articles that responded to strict, well defined criteria were taken into account, 29 series were studied including 266 patents. All of these patients received all possible medical treatments. One hundred nine of them (56%) had a permanent stimulator, and the rate of implantation of the different teams varied from 55% [11] to 80% [12]. Our series confirms these data with a rate of implantation of 72.5%. The average age of patients in our series was similar to that in published series. The percentage of women in our study (82.5%) was also similar to rates reported in the literature (70 to 88%). Incontinence improved in eighty three percent of the patients implanted in our study, but the Vaizey score did not reach zero in any of them. Our results were not as good as those in the literature, since certain teams showed a return to normal continence in
Score 25 20 15 10 5 0
F56 F45 F53 F67 F55 M90 F68 F48 F55 M59 F44 F69 F72 F59 F54 F72 M80 F72 F41 M64 F63 F73 F53 F52
Before sacral neuromodulation
6 months
Fig. 1 – Functional results according to Vaizey’s score before and 6 months after sacral neuromodulation in 24 patients with clinical improvement. Résultat fonctionnel clinique selon le score de Vaizey (axe vertical) avant et 6 mois après neuromodulation chez 24 patients (Sexe, âge en axe horizontal) ayant eu une amélioration clinique. Table II. – Results of anorectal manometry before and 6 months after sacral neuromodulation (mean and range). Résultats de la manométrie ano-rectale avant et 6 mois après neuromodulation des racines sacrées (moyenne et extrêmes). Before neuromodulation
After neuromodulation
P
Resting pressure (cm of water)
57 (27-90)
46 (25-70)
NS
Contraction pressure (cm of water)
92 (19-190)
84 (8-208)
NS
19 (4-39)
18 (11-25)
NS
Perception threshold volume (mL)
29 (10-100)
40 (10-100)
NS
Maximum tolerable volume (mL)
285 (200-400)
280 (150-450)
NS
Volume triggering the RRAI (mL)
20 (10-30)
17 (10-50)
NS
Duration of contraction (sec)
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41 to 75% of cases [10]. The first explanation is that incontinence for gas persisted in some of the patients in our study resulting in significant discomfort, especially socially. The second reason could be because many of our patients continued to use protection, either out of habit or unfounded fear (which they admitted to) or because of persistent urinary incontinence, although there was no anal soiling in any of these cases. The third explanation is that we used a very sensitive score of anal incontinence and although patients often noted a reduction in the number of stool leaks, and an improvement in their well-being, this was not true for incontinence for gas and the use of protection. The improvement would have been considered more significant (but perhaps less real?) if we had simply considered the reduction in the number of loss of stools during the study period, like for example Rosen [12] or Vaizey [13]. In this study the clinical improvement was not associated with a manometric improvement. Stimulation of the sacral nerve, in particular during the test electrode implantation acted directly on the pudendal nerve resulting in a contraction of the anal sphincter apparatus. But chronic stimulation at a low frequency (around 15Hz) probably acts on several levels and on both the efferent and afferent nerves [14]. In fact, the physiological explanation for the efficacy of neuromodulation on anal incontinence is not clear [11]. Considering the great variations in manometric results found in the major published studies: 5 studies show an increase in resting pressure and voluntary contraction pressure [12,15-18], 6 studies show an increase in the contraction pressure alone [5, 11, 13, 19-21] and two studies do not show any significant modification in resting or contraction pressures [14, 22], like our series. Neuromodulation probably acts by a complex mechanism associated with stimulations and inhibitions in varying degrees; actions on the anal sphincter as well as the upper colon, modifications in rectal motricity, but also of its sensitivity and of compliance [14]. Other studies on should be performed to investigated physiological criteria with more patients and more in depth comparison of clinical-manometric and clinco-electromyographic data. In conclusion, neuromodulation of the sacral nerves seems to be a safe and effective technique for the treatment of anal incontinence in selected patients. However, there does not seem to be any correlation between clinical and manometric results. Other physiological studies should be performed for a better understanding of the mechanism of action.
Report of 14 consecutive implantations. Dis Colon Rectum 1996; 39:1352-5.
5. Matzel KE, Stadelmaier U, Hohenfellner M, Gall FP. Electrical stimulation of sacral spinal nerves for treatment of faecal incontinence. Lancet 1995;346:1124-7.
6. Tanagho EA, Schmidt RA. Bladder pacemaker: scientific basis and clinical future. Urology 1982;20:614-9.
7. Pettit PD, Thompson JR, Chen AH. Sacral neuromodulation: new applications in the treatment of female pelvic floor dysfunction. Curr Opin Obstet Gynecol 2002;14:521-5.
8. Vaizey CJ, Carapeti E, Cahill JA, Kamm MA. Prospective comparison of faecal incontinence grading systems. Gut 1999;44:77-80.
9. Faucheron JL, Dubreuil A. Rectal akinesia as a new cause of impaired defecation. Dis Colon Rectum 2000;43:1545-9.
10. Jarrett ME, Mowatt G, Glazener CM, Fraser C, Nicholls RJ, Grant AM, et al. Systematic review of sacral nerve stimulation for faecal incontinence and constipation. Br J Surg 2004;91:1559-69.
11. Leroi AM, Michot F, Grise P, Denis P. Effect of sacral nerve stimulation in patients with fecal and urinary incontinence. Dis Colon Rectum 2001;44:779-89.
12. Rosen HR, Urbarz C, Holzer B, Novi G, Schiessel R. Sacral nerve stimulation as a treatment for fecal incontinence. Gastroenterology 2001;121:536-41.
13. Vaizey CJ, Kamm MA, Roy AJ, Nicholls RJ. Double-blind crossover study of sacral nerve stimulation for fecal incontinence. Dis Colon Rectum 2000;43:298-302.
14. Uludag O, Koch SM, van Gemert WG, Dejong CH, Baeten CG. Sacral neuromodulation in patients with fecal incontinence: a singlecenter study. Dis Colon Rectum 2004;47:1350-7.
15. Ganio E, Luc AR, Clerico G, Trompetto M. Sacral nerve stimulation for treatment of fecal incontinence: a novel approach for intractable fecal incontinence. Dis Colon Rectum 2001;44:619-29.
16. Ganio E, Ratto C, Masin A, Luc AR, Doglietto GB, Dodi G, et al. Neuromodulation for fecal incontinence: outcome in 16 patients with definitive implant. The initial Italian Sacral Neurostimulation Group (GINS) experience. Dis Colon Rectum 2001;44:965-70.
17. Kenefick NJ, Vaizey CJ, Cohen RC, Nicholls RJ, Kamm MA. Medium-term results of permanent sacral nerve stimulation for faecal incontinence. Br J Surg 2002;89:896-901.
18. Kenefick NJ, Vaizey CJ, Nicholls RJ, Cohen R, Kamm MA. Sacral nerve stimulation for faecal incontinence due to systemic sclerosis. Gut 2002;51:881-3.
19. Matzel KE, Stadelmaier U, Hohenfellner M, Hohenberger W. Chronic sacral spinal nerve stimulation for fecal incontinence: long-term results with foramen and cuff electrodes. Dis Colon Rectum 2001;44: 59-66.
REFERENCES
1. Faucheron JL, Risse O, Desroches E. Réparation sphinctérienne anale. J Chir (Paris) 2002;139:156-9.
20. Ripetti V, Caputo D, Ausania F, Esposito E, Bruni R, Arullani A.
2. Baig MK, Wexner SD. Factors predictive of outcome after surgery for
Sacral nerve neuromodulation improves physical, psychological and social quality of life in patients with fecal incontinence. Tech Coloproctol 2002;6:147-52.
faecal incontinence. Br J Surg 2000;87:1316-30.
3. Madoff RD, Rosen HR, Baeten CG, LaFontaine LJ, Cavina E, Devesa M, et al. Safety and efficacy of dynamic muscle plasty for anal incontinence: lessons from a prospective, multicenter trial. Gastroenterology 1999;116:549-56.
21. Vaizey CJ, Kamm MA, Turner IC, Nicholls RJ, Woloszko J. Effects
4. Lehur PA, Michot F, Denis P, Grise P, Leborgne J, Teniere P,
22. Malouf AJ, Vaizey CJ, Nicholls RJ, Kamm MA. Permanent sacral
of short term sacral nerve stimulation on anal and rectal function in patients with anal incontinence. Gut 1999;44:407-12. nerve stimulation for fecal incontinence. Ann Surg 2000;232:143-8.
et al. Results of artificial sphincter in severe anal incontinence.
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Gastroenterol Clin Biol 2006;30:669-672
Sacral neuromodulation in the treatment of severe anal incontinence ORIGINAL ARTICLE
Forty consecutive cases treated in one institution Jean-Luc FAUCHERON (1), Richard BOST (2), Virginie DUFFOURNET (3), Simon DUPUY (1), Nicolas CARDIN (1), Bruno BONAZ (2)
(1) Unité de Chirurgie Colorectale, Département de Chirurgie Digestive et de l’Urgence, (2) Département d’Hépatogastroentérologie, Hôpital Albert Michallon, Grenoble ; (3) Service de Médecine, Centre Hospitalier d’Annecy.
SUMMARY
RÉSUMÉ
Introduction — Sacral neuromodulation is a recognized therapeutic option in severe anal incontinence from neurogenic origins, when medical treatment has failed.
La neuromodulation sacrée dans le traitement de l’incontinence anale sévère : à propos de 40 cas consécutifs traités dans une seule institution
Methods — We report the results of this procedure applied in 40 consecutive patients operated on by a single surgeon from August 2001 to June 2004. Mean duration of incontinence was 5 years. There were 33 women and 7 men of mean age 59 (range 29-89). All patients had had medical treatment, 26 had had physiotherapy and 9 had been previously operated on for that problem. Neuromodulation consisted in a temporary electrical stimulation test followed by implantation of a stimulator in case of efficacy.
Jean-Luc FAUCHERON, Richard BOST, Virginie DUFFOURNET, Simon DUPUY, Nicolas CARDIN, Bruno BONAZ
(Gastroenterol Clin Biol 2006;30:669-672)
Introduction — La neuromodulation peut être proposée dans le traitement d’une incontinence anale sévère d’origine neurogène ou idiopathique, lorsque le traitement médical a échoué. Méthodes — Nous rapportons les résultats de ce traitement chez 40 malades consécutifs traités par le même chirurgien entre août 2001 et juin 2004. La durée moyenne de l’incontinence était de 5 ans. Il s’agissait de 33 femmes et 7 hommes, d’une moyenne d’âge de 59 ans (29-89). Tous les malades avaient eu un traitement médical, 26 une rééducation et 9 une intervention chirurgicale. La neuromodulation consistait en un test temporaire de stimulation sacrée, suivi en cas d’efficacité par l’implantation définitive d’un neurostimulateur.
Results — Twenty nine patients had a positive test and were implanted. Ten had a negative test and one is waiting for implantation. From the 29 patients, 23 had uneventful postoperative course. Incontinence score varied from 17 before neuromodulation to 6 after in the 24 patients who were improved. Mean resting pressure, mean maximum squeeze pressure and mean duration of squeeze pressure did not change from pre to postoperative period.
Résultats — Vingt-neuf des 40 malades ont eu un test positif, qui a conduit à l’implantation définitive. Parmi les 11 autres malades, 10 ont eu un échec de la stimulation externe et le onzième attend l’implantation. Parmi les 29 malades, 23 ont eu des suites simples. L’incontinence anale, jugée sur le score de Vaizey, est passée de 17 à 6 après l’implantation chez les 24 malades ayant eu une amélioration. La pression moyenne de repos chez ces malades est passée de 57 à 46 cm d’eau (NS) et la pression moyenne de contraction de 92 à 84 cm d’eau (NS). La durée moyenne de contraction volontaire est passée de 19 à 18 secondes (NS).
Conclusion — Sacral neuromodulation is a safe and efficacious procedure in properly selected anal incontinent patients. However, we observed no correlation between clinical and manometric data.
Conclusions — La neuromodulation est une technique sûre et efficace chez les malades incontinents sélectionnés. Cependant, il ne semble pas y avoir de corrélation entre les résultats cliniques et les résultats manométriques.
types of effort induced urinary incontinence and certain dysurias [6]. The efficacy of this technique on anal incontinence was discovered nearly fortuitously in patients treated for urinary incontinence who showed improvement of their associated digestive symptoms [7]. As a result neuromodulation was proposed in 1995 in the treatment of anal incontinence alone [5]. We report the surgical and functional results of this treatment in 40 consecutive patients with severe anal incontinence who did not respond to other techniques.
Introduction Surgical treatment of anal incontinence includes direct repair of the sphincter in case of rupture [1, 2], substitution of the sphincter by muscle plasty which may be dynamic [3] implantation of an artificial sphincter when the sphincter cannot be repaired, [4] and for the last ten years or so, sacral neuromodulation, which is mainly indicated in anal incontinence from neurogenic causes [5]. The first implantations of a stimulator for sacral nerve neuromodulation were performed in 1981 for the treatment of certain
Patients and methods
Reprints: J.L. FAUCHERON, Unité de Chirurgie Colorectale, Département de Chirurgie Digestive et de l’Urgence, BP 217, 38043 Grenoble. E-mail : [email protected]
From August 2001 to June 2004, 40 patients including 33 women, an average of 59 years old (range 29-89) underwent a test period of sacral nerve stimulation for severe anal incontinence that had lasted for an average of at least 5 years (range 1-31 years). All patients had
669
J.L. Faucheron et al.
tocks using a 10 cm extension cord. The stimulator is programmed by the operator, thanks to a percutaneous telemetric programmer. The following parameters can be modified: amplitude (1-10 volts), frequency (around 15 Hz for this indication), duration of the impulse (approximately 210 microseconds for this indication) as well as the charge of the four contacts of the electrode and the case (neutral, positive or negative). The programmer also makes it possible to know the impedance of the system (in ohms), the percentage of use of the stimulator and the estimated life of the battery. The patient has a simple remote control case which allows him to change the amplitude within the range determined by the operator and to stop stimulation (which is not pertinent for an indication of sacral nerve stimulation). Each patient undergoes a check-up before the first intervention including a clinical examination and questions to determine the Vaizey score [8], pelvic examination, endoanal ultrasound, anorectal manometry and an electromyogram. Other examinations may be performed if necessary: dynamic colpocystodefecography (to eliminate the presence of a static or dynamic pelvis) [9], a colonoscopy (in case of rectal bleeding, transit problems or a family history of cancer), colon transit time (to differentiate transit constipation from dyschesia, for example), sacral X ray (if a traumatic, tumoral or other bone lesion is suspected), pelvic Tomodensitometry, MRI, or an MRI of the medullary canal (if a medullary lesion is suspected. These examinations can then lead to more sophisticated tests (EMG of the lower limbs, if neurological disease is suspected for example). After the second operation, all the patients were seen at 1, 3, 6, 12, 18 and 24 months. Besides a clinical examination to establish the Vaizey score, manometry was obtained during the 3rd and 6th months. If electrode displacement was suspected, three dimensional sacral TDM was performed.
already received medical treatment associated with a diet and 26 had received biofeedback training. Nine of the patients had already undergone surgery for anal incontinence: five had had direct reparation (two requiring more than one intervention) that had been effective from a morphological standpoint, and four underwent dynamic muscle plasty before neuromodulation came into use. The cause of anal incontinence is summarized in table I.
Methods Neuromodulation includes two surgical steps which can be performed under general or local anesthesia. The first step involves implantation of a finned electrode into the 3rd or 4th right or left sacral roots, with the patient in the decubitus ventral position, their feet off the table with the perianal region in the operating field. The correct positioning of the electrode is defined clinically and by an X-ray of the profile under a brilliance amplifier. Clinically, successive stimulation of the 4 contacts of the electrode by an external electric stimulator administering 1 to 10 volts should cause a sensation in the perinium which is difficult to describe (and which is obviously absent under general anesthesia), an anal contraction associating closure and ascension of the anus by stimulation of the external sphincter and the elevator muscles of the anus (under general anesthesia, curare should not be used) as well as irregular flexing of the toes. The X-ray helps confirm the exact position of the electrode; position, depth and direction. In practice the fins help prevent migration of the electrode, stimulation is first administered through a hollow needle, then replaced by the electrode thanks to a kit based on the Seldinger technique. The implanted electrode is then attached to an extension, connected to the external stimulator and emerging from the supero-external quadrant of the controlateral buttock. The patient is then rapidly and easily trained to use the external stimulator at home and during all normal activities. The patient must wear the stimulator night and day on his waist, increasing the voltage to maximum and leaving the frequency around 10 Hz. A detailed record of all stools must be noted, in the same way the patient did before the intervention: frequency of transit, frequency and importance of leaking, the level of urgency of stools; a space is left for comments, which can provide important information (it is not unusual to learn that transit has normalized, stools have become harder and any associated urinary leaking has disappeared, or that the sex drive increases). The patient is seen 8 to 15 days later (depending on the availability of the patient and the physician) and the record of stools is studied by the surgeon: if the number of leaks is reduced by at least 50%, and the patient has not modified his lifestyle, diet, or taken any medication that slows transit, the test is considered positive and permanent implantation of a stimulator is suggested (MEDTRONIC 3023) during a second intervention. The second surgical intervention is performed with the patient in the decubitus ventral position, but this time, the feet can be placed on the table and the anus isolated in the surgical field. The incision at the level of the electrode and the extension is enlarged and the electrode is attached to a MEDTRONIC 3023 neurostimulator, placed in a subcutaneous muscle chamber of the superoexternal quadrant of the homolateral but-
Statistical Analyses All the quantitative data were compared using the Wilcoxon test.
Results Surgical results None of the patients were lost to follow up. Twenty nine of the 40 patients tested for severe anal incontinence had implantation of a neurostimulator. There were no deaths. After the first intervention, there was no morbidity in any of the 40 patients. Most complications occurred after the second intervention. Infection at the remote control site resulted in removal of the implant in two cases; in one obese patient with diabetes that had not been stabilized; despite the infection, the patient insisted on keeping the stimulator for 9 months because it was effective. The surgeon convinced her to remove the implant, and a new implant was successfully put in place 11 months later. In the second patient there was a simple erythema at the exit spot of the extension cord at the time of implantation, while a bacteriological skin sample was negative for any aggressive germ and the dermatologist was not against the procedure. The site became infected several days later, the muscle chamber of the remote control case was washed and eventually the implant was removed. In a third patient, due to a persistent seroma a simple needle aspiration was performed with sterile results during the first month follow up visit. A fourth patient experienced pain at the remote control site. This patient was a high level sportsman, who was very muscular, so the location of the stimulator was changed. In the fifth case, sudden worsening of the functional results (recurrence of anal incontinence) associated with a sensation of electrical discharge and burning in the buttocks when the amplitude was increased, confirmed diagnosis of a displaced electrode. This complication was confirmed by TDM and a new electrode was successfully implanted under general anesthesia. The cause of displacement was not identified. The last complication in a sixth patient occurred when the neurostimulator lost its charge prematurely, so that it had to be replaced along with a
Table I. – Causes of anal incontinence. Etiologie de l’incontinence anale. Cause
N
Pudendal neuropathy
16
Idiopathic incontinence *
7
Cauda equina syndrome
5
Peripheral neuropathy
3
Sphincter repair
3
Other **
6
Total
40
* Incontinence was considered idiopathic when there was no identified organic cause and the EMG did not show any increase in the distal latency of the pudendal nerve. ** Radiation and postoperative fibrosis: 2; rectopexy: 1; stroke: 1; sacral resection : 1 and traumatic medullary lesion : 1.
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Sacral neuromodulation
new electrode, 3 years and five months after the first implantation. This may be because the configuration of the parameters of the four electrode contacts were not optimal — the electrode was not in a good position — so that an elevated amplitude (more than 3 volts at all times, and up to 8 volts) was necessary for effective neurostimulation.
when the electrode was functioning and correctly placed. The eleventh patient is waiting for implantation. The alleged clinical improvement of 24 patients based on the Vaizey score was not accompanied by improvement in manometric paramenters (table II). The average resting pressure, the average pressure during voluntary squeezing and the average duration of this contraction were even lower after implantation of the stimulator than before the test.
Functional results Anal incontinence improved in twenty four of the 29 implanted patients at the sixth month of follow up. In these patients, the Vaisey score went from an average of 17/24 before the test to 6/24, six months after implantation of the stimulator. Details for each patient are found in figure 1. Of the 11 patients who underwent the test but who were not implanted, the indication was considered inappropriate in 5 cases a posteriori. The first patient had become incontinent after undergoing radiotherapy and a proctetomy followed by a coloanal anastomosis complicated by suppuration. The second patient presented with moderate anal incontinence from a pudendal neuropathy associated with perineoanal-buttocks pain which was not relieved. The third patient was 89 years old, with anal soiling cause by severe dyschezia with the development of scatomas requiring laxatives. Besides anal incontinence, the fourth patient had numerous sequellae from a rectopexy by laparotomy for rectal prolapsus, performed in another institution. The fifth patient had anal incontinence with radiation induced rectitis. These five cases were among the first 20 patients. Five other patients who underwent an external neurostimulation test were considered to be real failures, because there was no reduction in the number of anal leakages or less than 50% reduction in the number of anal leaks
Discussion The indications for neuromodulation were recently described in a review of the literature performed by Jarret et al. [10]. In this same paper the authors identified 106 articles on the subject of sacral neuromodulation for the treatment of anal incontinence. When only those articles that responded to strict, well defined criteria were taken into account, 29 series were studied including 266 patents. All of these patients received all possible medical treatments. One hundred nine of them (56%) had a permanent stimulator, and the rate of implantation of the different teams varied from 55% [11] to 80% [12]. Our series confirms these data with a rate of implantation of 72.5%. The average age of patients in our series was similar to that in published series. The percentage of women in our study (82.5%) was also similar to rates reported in the literature (70 to 88%). Incontinence improved in eighty three percent of the patients implanted in our study, but the Vaizey score did not reach zero in any of them. Our results were not as good as those in the literature, since certain teams showed a return to normal continence in
Score 25 20 15 10 5 0
F56 F45 F53 F67 F55 M90 F68 F48 F55 M59 F44 F69 F72 F59 F54 F72 M80 F72 F41 M64 F63 F73 F53 F52
Before sacral neuromodulation
6 months
Fig. 1 – Functional results according to Vaizey’s score before and 6 months after sacral neuromodulation in 24 patients with clinical improvement. Résultat fonctionnel clinique selon le score de Vaizey (axe vertical) avant et 6 mois après neuromodulation chez 24 patients (Sexe, âge en axe horizontal) ayant eu une amélioration clinique. Table II. – Results of anorectal manometry before and 6 months after sacral neuromodulation (mean and range). Résultats de la manométrie ano-rectale avant et 6 mois après neuromodulation des racines sacrées (moyenne et extrêmes). Before neuromodulation
After neuromodulation
P
Resting pressure (cm of water)
57 (27-90)
46 (25-70)
NS
Contraction pressure (cm of water)
92 (19-190)
84 (8-208)
NS
19 (4-39)
18 (11-25)
NS
Perception threshold volume (mL)
29 (10-100)
40 (10-100)
NS
Maximum tolerable volume (mL)
285 (200-400)
280 (150-450)
NS
Volume triggering the RRAI (mL)
20 (10-30)
17 (10-50)
NS
Duration of contraction (sec)
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J.L. Faucheron et al.
41 to 75% of cases [10]. The first explanation is that incontinence for gas persisted in some of the patients in our study resulting in significant discomfort, especially socially. The second reason could be because many of our patients continued to use protection, either out of habit or unfounded fear (which they admitted to) or because of persistent urinary incontinence, although there was no anal soiling in any of these cases. The third explanation is that we used a very sensitive score of anal incontinence and although patients often noted a reduction in the number of stool leaks, and an improvement in their well-being, this was not true for incontinence for gas and the use of protection. The improvement would have been considered more significant (but perhaps less real?) if we had simply considered the reduction in the number of loss of stools during the study period, like for example Rosen [12] or Vaizey [13]. In this study the clinical improvement was not associated with a manometric improvement. Stimulation of the sacral nerve, in particular during the test electrode implantation acted directly on the pudendal nerve resulting in a contraction of the anal sphincter apparatus. But chronic stimulation at a low frequency (around 15Hz) probably acts on several levels and on both the efferent and afferent nerves [14]. In fact, the physiological explanation for the efficacy of neuromodulation on anal incontinence is not clear [11]. Considering the great variations in manometric results found in the major published studies: 5 studies show an increase in resting pressure and voluntary contraction pressure [12,15-18], 6 studies show an increase in the contraction pressure alone [5, 11, 13, 19-21] and two studies do not show any significant modification in resting or contraction pressures [14, 22], like our series. Neuromodulation probably acts by a complex mechanism associated with stimulations and inhibitions in varying degrees; actions on the anal sphincter as well as the upper colon, modifications in rectal motricity, but also of its sensitivity and of compliance [14]. Other studies on should be performed to investigated physiological criteria with more patients and more in depth comparison of clinical-manometric and clinco-electromyographic data. In conclusion, neuromodulation of the sacral nerves seems to be a safe and effective technique for the treatment of anal incontinence in selected patients. However, there does not seem to be any correlation between clinical and manometric results. Other physiological studies should be performed for a better understanding of the mechanism of action.
Report of 14 consecutive implantations. Dis Colon Rectum 1996; 39:1352-5.
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