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| 번호 | 제목 | 등록일 | 조회수 |
|---|---|---|---|
| 22 | The Cutting Seton [2001년 5월 DCR] | 2011-11-17 | 3332 |
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An Experience at King Faisal Specialist Hospital
William H. Isbister, M.D., Ch.B., Nasser A1 Sanea, M.B., Ch.B.
From the Colorectal Unit, Department of Surgery, King Faisal Specialist Hospital, Riyadh, Kingdom of
Saudi Arabia PURPOSE: A 30-percent gas incontinence rate has been reported after the use of the cutting seton in complex anal fistulas. This study was undertaken to determine the morbidity and efficacy of the cutting seton in the management of complex anal fistulas at the King Falsal Specialist Hospital.
METHODS: All patients who had a cutting seton inserted in the colorectal unit at King Faisal Specialist Hospital between 1990 and 1998 were identified from a colorectaI data base. The charts of these patients were examined and form the basis of this report. Setons were inserted and tied under general anesthesia after the fistula tract had been identified. All fistulas were transsphincteric, and if it seemed that more than 30 percent of the internal sphincter would need to be divided to "lay open" the tract, a seton was used. Fistulas were designated "high" if the internal opening was above the level of the anal crypts. Setons were tightened under general anesthesia at intervals of three to four weeks until cutting was complete. Patients were followed up until wounds had healed and fistula symptoms had resolved. RESULTS: Data from 47 patients were analyzed. The mean duration of disease before surgery was 39.1 months. Twenty-five patients had had previous anorectal abscess drainage. The mean number of previous fistula operations was 2.2. Before seton insertion five patients were incontinent to gas, two to liquid stool, and none to solid stool. Continence status before seton surgery was unknown in 11 patients. There were 16 "high." fistulas. Methylene blue dye was used to identify the internal opening in 14 patients when simple probing failed. Setons were tightened on three or more occasions in 12 patients, twice in 19 patients, and once in 16 patients. Mean perineal wound healing time was six months. The mean length of follow-up was 1.1 years, and during this time one fistula recurred. After treatment a total of 17 patients (36.2 percent) were incontinent to gas, 4 to liquid feces (8.5 percenO, and 1 to solid feces (2.3 percent). Four patients complained of soiling. Of previously continent patients, 9.5 percent were significantly incontinent to gas, but in addition 21.4 percent were "occasionally" incontinent for gas. CONCLUSION: The use of the cutting seton resulted in a significant gas incontinence, rate of 9.5 percent after a mean follow-up of 1.1 years. Only 1 fistula recurred.
The first use of the "cutting seton" in patients with fistula-in-ano is attributed to Hippocrates, although
the use of a medicated noncutting seton was described several centuries earlier. Since these first descriptions there have been many variations in technique and at the King Faisal Specialist Hospital we
have used the cutting seton in selected patients with anal fistula since 1990. It has been suggested that although the cutting seton yields fairly good results in regard to cure of the fistula, the risk of incontinence, despite its minor degree, seems to be too high to recommend its use for all high fistulas. A 0 to 63 percent gas incontinence rate has been reported after the use of the cutting seton in complex anal fistulas. This study was undertaken to determine the morbidity and efficacy of the cutting seton in the management of anal fismtas at the King Faisal Specialist Hospital. DISCUSSION
Any surgical procedure involving the anal canal has the potential to cause damage to the anal sphincters and thus result in some degree of anal incontinence. The aim of surgery in this region is thus to ensure minimal sphincter damage while at the same time producing maximum resolution of symptoms. Patients with simple anal fistulas can undergo laying open of their fistulas with the expectation that the fistula will be cured and that they will have few postoperative problems in relation to continence. If a patient has already had many abscess or fistula operations, on the other hand, it is likely that he or she will have a complex and often high transsphincteric or suprasphincteric fistula and this will prove to be much more difficult to manage. One of the ways of managing such a complex fistula is with a cutting seton, and this article describes our experience with this technique with particular reference to resolution of symptoms and continence. It was not our aim to discuss the different ways of managing complex fistulas, because we have no data relating to the other methods suggested. There have been several techniques described for tightening the cutting seton, but we have only used the method described above in this article.
All of the fistulas included in our analysis were transsphincteric, and we chose to classify all fistulas
as "high" or "low" depending on the anatomic relationship of the internal openings to the anal crypts and the opening of the anal glands. We were not able to classify the fistulas in a more detailed way, because 41 of our patients had had previous surgery for anorectal abscess or anal fistula or both before referral. The overall average number of operations per patient before referral was 2.8, and some patients had had as many as eight previous surgeries. "The different parts of the sphincter are difficult to identify at operation in normal conditions, to say nothing of when they are infiltrated by an inflammatory process. '' In patients who have had previous surgeries, this problem is compounded and "it must be remembered that the fibrosis of previous operations sometimes so obscures the anatomy that it is impossible to be sure of the exact position of the puborectalis" even. Relatively few studies that document the use of the cutting seton and its complications in patients with
complex anal fistula were found on searching MEDLINE (1966-1999). Considerable discrepancy existed in relation to the development of incontinence after the use of the cutting seton, and rates as low- as 0 or as high as 63 percent were found. In one study, in which a cutting seton was used in 28 patients with high recurrent fistulas, there were no patients who reported anal incontinence at follow-up. 13 In another study 7 of 13 patients (54 percent), in which high anal fistulas were treated with a cutting seton over a sixyear period, developed minor incontinence. In a further study 22 of 35 patients (63 percent) who attended for follow-up reported symptoms of minor anal incontinence. Finally, 3 of 16 patients (19 percen), who were available for long-term follow-up (>12 months after discharge), reported deterioration in continence after seton treatment. 18 Of these, three had minor incontinence before seton treatment, and all patients had had rectovaginal fistulas. It was clear from the above studies that the definition of "continence" itself played a major part in determining the reported incontinence rate. In addition, the time at which continence was assessed and the presence or absence of previous problems consequent on previous surgery were also important determining factors in relation to the final outcome, has previously been suggested that such discrepant results could most likely be explained by the methodology used to determine the functional outcomes, and because these varied so widely, it was probably impossible to accurately compare any two studies. More importantly, it seems that "minor transient incontinence to gas and liquid" occurs in many individuals after almost any type of anorectal surgery, including lateral internal sphincterotomy, hemorrhoidectomy, and simple fistulotomy. It is important therefore, when tempted to discount a technique based on a high reported "minor" incontinence rate, to remember that most procedures carry similar rates and that the primary determinant for the use or abandonment of such a technique should perhaps be the technique's success inneradicating the primary disease problem, i.e., the recurrence
rate. The confusion, however, does not stop here. In an article addressing the factors affecting continence after surgery for anal fistula, it was concluded that incontinence was related to low resting pressure, reflecting intemal sphincter integrity and to local epithelial electrosensitivity (reflecting scaring) but not to squeeze pressure, fistula type, or surgical treatment. It thus seemed that minimal damage to the anoderm and internal sphincter was paramount in retaining continence. In another study from the same institution, it was stated that when division of the external sphincter was used in treating transsphincteric fistulas, a low- anal pressure was found in the distal 3 cm of the anal canal, and a higher number of patients with impaired continence to flatus and liquid stool could be expected. Preservation of the external sphincter muscle masses was suggested in treating transspbincteric and suprasphincteric fistulas. In patients in whom the external sphincter was preserved by excising the tract as much as possible and draining the secondary tracts, both resting and voluntary contraction pressures were not significantly reduced, and fewer patients had disturbed control. It thus seems that the external sphincter is also important in maintaining continence. The goal in fistula surgery, therefore, must be to divide as little as possible of either sphincter commensurate with a resolution of symptoms. The cutting seton, by slowly cutting through the muscle mass over a period of several weeks as opposed to the rapid cutting reported in one study with high incontinence rates, may be one of the better methods of obtaining this goal. Postoperative continence did not seem to be greatly dependent on internal sphincter function in 83
patients undergoing a manometric examination both preoperatively and postoperatively, despite the finding of a significant decrease in resting tone in the postoperative period. By assessing the preoperative tone, it was suggested that surgery for anal fistulas performed with awareness of an individual patient's anal sphincter function allowed the surgeon to decrease the risk of postoperative incontinence by using setons in patients with poor tone more liberally, whereas patients with good preoperative tone would be more likely to have a satisfactory result after fistulotomy. Greater use of the seton was recommended to avoid division of striated muscle in patients with high fistulas. Multivariate analysis has suggested that horseshoe extension, fistula type, surgeon, location of the internal opening, and previous fistula surgery were factors considered to be strongly associated with recurrence, in general, after the surgical treatment of fistula-inano. Thus, transsphincteric and suprasphincteric fistulas with anterior internal openings in patients after previous fistula surgery, all factors commonly associated with complex fistulas managed in a tertiary referral hospital, represent the features of fistulas which have a high predictive value for recurrence. Variations in the case mix of patients may thus be an important factor in determining the different rates of recurrence and incontinence reported in the literature after the use of the cutting seton for complex fistulas.
A two-staged cutting technique has been described, but we have no experience of this. In one description the internal and external sphincter muscles were divided up to the level of the dentate line and a seton was placed through the fistula tract and tied loosely. After a minimum of three months, the seton was gradually tightened and the remainder of the sphincter musculature was divided. Five patients, managed in this way, maintained their anal sphincter pressures and had unchanged anal continence without recurrence. All patients had either suprasphincteric or extrasphincteric fistulas. All patients had defunctioning colostomies. In an alternative technique, after passing a nonabsorbable seton through the fistula tract, the skin and the subcutaneous tissues underlying the seton were incised, and sometimes parts of the internal and external sphincter were included. The seton was tied snugly
around the remaining part of the external sphincter, the wound was left open ,and if after fore" weeks scar tissue remained at the site of the seton, the scar was divided surgically. In 29 patients managed in this way with high transsphincteric fistulas, incontinence was evaluated by questionnaire at a mean of 46 months after surgery. The recurrence rate was 8 percent, and after exclusion of 4 patients with inflammatory bowel disease, 11 (44 percent) complained of incontinence. The two-stage seton technique has been compared with the simple cutting seton technique, and it was found that both techniques were equally effective in eradicating fistulas, but both were associated with similarly rather high incontinence and recurrence rates (50 and 9 percent). There seems to be little in any of these studies to warrant a change from the simpler and original cutting seton technique. In addition, the recurrence rate of 2 percent found in the present study compared favorably with other rates reported in the literature (0-6 percent) in which the same technique has been used. All patients with "high" fistulas had had previous fistula or anorectal abscess surgery and this strongly supports the hypothesis that all high fistulas of cryptoglandular origin are iatrogenically created by inappropriate instrumentation during surgery for either the fistula itself or the related abscess.
Four fistulas failed to obey Goodsall's rule, and all four patients had had previous surgery. It has been suggested previously that the ruIe seems to be more accurate when applied to posterior external anal openings than when applied to anteriorly situated external openings, but we were unable to confirm or refute this suggestion.
Fistulography was not found to be very helpful in determining the site of the internal communication of
the tract, and endoanal ultrasound was not available. Injection of hydrogen peroxide was not used because of reports of near-fatal air embolism after its use for irrigating in closed spaces. Patients with complex anal fistulas who have had multiple surgeries constitute a real challenge for the
surgeon. Recurrence rates may be high if inadequate operations are performed, and incontinence rates may be high if too aggressive an attitude is adopted toward the sphincter musculature. It would seem that the use of the cutting seton, a technique now many hundreds of years old, is a technique that can be used in this difficult group of patients who have frequently become disenchanted with surgery. The use of the cutting seton in our patients has resulted in a good resolution of symptoms and a significant gas incontinence rate of 9.3 percent.
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