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| 번호 | 제목 | 등록일 | 조회수 |
|---|---|---|---|
| 14 | Internal Anal Sphincter Augmentation for Fecal Incontinence Using Injectable Silicone Biomaterial [2001년 4월 DCR] | 2011-11-12 | 3240 |
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Andrew J. Malouf, F.R.A.C.S., Carolynne J. Vaizey, M.D., F.R.C.S.(Gen), F.C.S.(SA),
Christine S. Norton, M.A., R.G.N., Michael A. Kamm, M.D., F.R.C.P., F.R.A.C.P. From St. Mark's Hospital, London, United Kingdom
PURPOSE: A disrupted or weak internal anal sphincter can lead to passive fecal incontinence. This muscle is not amenable to direct surgical repair. Previous preliminary attempts to restore fimctional continuity have included a cutaneous flap to fill an anal canal defect, and injection therapy using polytetrafluoroethylene, collagen, or autologous fat. Urologists have also used injections of collagen or
silicone to enhance bladder neck function. This pilot study aimed to assess the efficacy of single or multiple injections of the silicone-based product Bioplastique TM for the symptoms of passive fecal incontinence caused by an anatomically disrupted or intact but weak internal anal sphincter. PATIENTS AND METHODS: Ten patients (6 females; median age, 64 ; range, 41-80 years) with passive incontinence secondary to a weak (n = 6) or disrupted (n = 4) internal anal sphincter were injected either circumferentially or at a single site, respectively. Patients were assessed before and six weeks after treatment by clinical assessment, two-week bowel diary card, anorectal physiologic testing, and endoanal ultrasound. Patients failing to show improvement after the first injection were offered a second injection six weeks after the first injection. Clinical assessment was further repeated at six months, and five patients had a further ultrasound examination. RESULTS: At six weeks, six of ten patients showed either marked improvement (n = 3) or complete cessation of leakage (n = 3). A further patient was greatly improved after a second injection. Three patients were not improved. At six months, two of the seven patients had maintained marked improvement, and one patient had maintained minor improvement; all of these three patients had circumferential multiple injections. Maximum resting and squeeze anal pressures did not differ significantly between before vs. six weeks after vs. six months after injection. At six weeks endoanal ultrasound (n = 9) confirmed the presence and correct position of the silicone in all but one patient who had experienced obvious external leakage of the product. At six months the silicone remained in the correct position in the five endosonographically assessed patients. Five of the initial patients experienced pain or minor ulceration at the injection site.
CONCLUSIONS: Although clinically effective immediately after injection, the benefit of an injectable biomaterial was maintained in only a minority of patients. This occurred despite the continued presence of material in the correct anatomical site. Patients with diffuse weakness treated by circumferential injection seemed to be the most responsive, but further studies are required to clarify this. DISCUSSION
This study has shown that it is technically possible to place biomateriaI accurately either at a single site of internal sphincter disruption or circumferentially to augment a weak or degenerate muscle. This treatment produced good results initially in a majority of patients. However, on longer follow-up the benefit was restricted to a small number of patients.
This was a pilot study designed to assess prospectively the feasibility of such a procedure, the technicaI requirements, and its short-term efficacy. It became clear from the first six patients treated that greater attention was required in relation to pain relief and prevention of infection. These issues were resolved by changes in technique applied to the last four patients. The use of extensive local anesthetic infiltration along the entire injection track and adequate analgesia after treatment resulted in elimination of pain as a problem. Laxative use in the last four patients also may have contributed to this effect.
Transsphincteric injection using a longer needle effectively prevented any signs of infection or leakage
of the injected material. Antibiotic treatment was also more intensive in the last four patients. Although more than one technique was used in this study, it should be appreciated that this was a pilot study intended to define the optimal practical aspects of administration of the biomaterial and to assess efficacy. Four patients had a single internal sphincter disruption. Such patients often have a normal maximum
anal resting pressure. However, an asymmetric pressure profile can be demonstrated on vector manometry, and the mechanism of leakage is presumed to be one of a gutter deformity, with inadequate circumferential closure of the anal canal. This forms the basis of treatment using a surgical skin flap. It also formed the theoretical basis of using a nonresorbable bulking agent at one injection site. Changes in the maximum recorded resting pressure were not expected and were not observed. A lack of significant manometric change was seen in a previous study of injectable collagen. At six months only two patients still had a marked, and one a slight, response to treatment. These were
three of the six patients with a diffusely weak sphincter. None of the four patients with a discrete disruption benefited. This may indicate that patients with diffuse weakness are more likely to respond to treatment. Alternatively, it may be that multiple injection sites are required to enhance anal canal occlusion and that patients with a single deficiency would benefit from multiple circumferential injections. Vascular filling of the anal cushions may contribute as much as 15 to 20 percent of the anal resting pressure and provide a compliant plug that forms a hermetic seal at the anal margin. These injections may act in a similar way to occlude the anal canal. Despite the endosonographic confirmation that the injected material was still present where injected, the
clinical effect wore off in some patients. This may relate to tissue accommodation to the injected material, with subsequent lack of compression of the anal canal. Animal studies have demonstrated that the carrier gel, polyvinylpyrrolidone, has been shown to be excreted over a three-day period. This is replaced by a fibrin and protocollagen matrix surrounding each microparticle. By six weeks there is replacement of the matrix with collagen fibrils with an overall stability of product bulk. At the time of the six-week review, there was good symptomatic relief in 70 percent of patients treated in the current study. The pattern of initial improvement and subsequent deterioration in some patients does not seem to correlate with the evidence from animal studies on maintenance of product bulk and the fact that the material was still palpably present. In summary, injection of a biomaterial that is nonresorbable or nonbiodegradable seems to offer shortterm benefit in a select minority of patients with fecal incontinence caused by internal sphincter pathology. The techniques for its administration have been defined. Further studies are required to define the longterm benefit in a wide range of sphincter pathologies. These results will also need to be compared with other sphincter-bulking therapies, which have so far only had their immediate and short-term results reported.
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