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| 번호 | 제목 | 등록일 | 조회수 |
|---|---|---|---|
| 110 | Direct Repair vs. Overlapping Sphincter Repair [2003년 7월 DCR] | 2011-11-17 | 3448 |
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A Randomized, Controlled Trial
J. J. Tjandra, M.D., F.R.A.C.S.,* W. R. Han, M.D.,* J. Goh, F.R.A.C.O.G.,†M. Carey, F.R.A.C.O.G.,† P. Dwyer, F.R.A.C.O.G.†
From the Departments of Colorectal Surgery, *Royal Melbourne Hospital, and †Royal Women’s Hospital,
Melbourne, Australia PURPOSE: The aim of this study was to compare the results of two surgical techniques (direct end-to-end vs. overlapping) of delayed repair of a localized anterior defect of external anal sphincter after an obstetric trauma.
METHODS: During a five-year period, 23 patients were randomly assigned to direct end-to-end repair (n = 12) or overlapping sphincter repair (n = 11), using 2-0 PDS™ sutures. Two patients from each group had an internal anal sphincter defect that also was repaired. All patients had a normal pudendal nerve terminal motor latency preoperatively. Evaluations included endoanal ultrasound, anorectal manometry,
and neurophysiologic evaluation. Continence was assessed by the Cleveland Clinic Continence Score (0–20; 0, perfect continence; 20, complete incontinence). RESULTS: The two groups were comparable with regard to age (median, 45 years), past history of sphincter repair (n = 2), and posterior vaginal repair. There was no major morbidity. The wound-healing rate was identical between the two groups. However, of the patients undergoing overlapping repair, two had fecal impaction, and one had a urinary retention. Median preoperative continence score was 17 in both the direct-repair group (score, 8–20) and the overlap group (score, 7–20). At a median follow-up of 18 months, the improvement in continence was similar between the two surgical groups, with a median continence score of 3, respectively. In both surgical groups there was a significant and similar improvement in maximum squeeze pressure and in the functional anal canal length postoperatively (P< 0.05), but the mean resting pressure was relatively unchanged. In the overlap group, one patient developed a unilaterally prolonged pudendal nerve terminal motor latency that was persistent 22 months after surgery, and two patients had impaired fecal evacuation postoperatively.
CONCLUSIONS: This randomized, controlled study suggests that the outcome is similar whether
direct end-to-end or overlapping repair of a sphincter defect is performed. Overlapping repair might be associated with more difficulties with fecal evacuation and a prolonged pudendal nerve terminal motor latency postoperatively. Most published series are about patients with a sphincter defect secondary to obstetric trauma, using an overlapping techniques to repair the divided anal sphincters. In 1940, the collective results of the American Proctological Society using a direct end-to-end sphincter repair technique were reported and failure rate as high as 40 percent was reported. Overlapping sphincteroplasty, as described by Parks and McPartlin in 1971 and later modified by Slade et al. is thought to be better and has been the predominant technique used during the last three decades by colon and rectal surgeons. However, a more recent review has indicated that results from overlapping anal sphincter repair for obstetric trauma are rarely perfect; often there are residual symptoms and some patients might develop new evacuation disorders.
There has been improved understanding of the anatomy and physiology of the pelvic floor, and, with
the advent of endoanal ultrasound and anorectal physiologic testing, a better selection of patients with a defined anal sphincter defect for surgical repair. Surgical techniques have improved, with better sutures and improved prophylaxis against sepsis. The purpose of this randomized, controlled trial is to compare the outcome of delayed anal sphincter repair using an end-to-end direct repair or an overlapping technique. DISCUSSION
Endoanal ultrasound and anorectal physiology testing have increased the diagnostic accuracy and
guided the management of patients with fecal incontinence. Endoanal ultrasound accurately defines the presence and extent of a sphincter defect. A prolonged PNTML indicates pudendal neuropathy and is suggested to be an important prognostic factor of poor outcome after sphincter repair. A prolonged PNTML is common in women with fecal incontinence and thus might cause a reporting bias in the outcome of a sphincter repair. Thus modern, colorectal practice with adjunctive investigative tools allows better case selection for a sphincter repair. This also will ensure a more meaningful comparison of results from different centers. Earlier descriptions of sphincter repair involved direct end-to-end repair. The high failure rate reported
in the 1940s was thought to be caused by sutures cutting out from the retracted muscle ends. Overlapping sphincter repair was considered better because the surface area in contact is increased, and the sutures are less likely to cut out. Since that time, most sphincter repair has used an overlapping technique, which has had a success rate of 47 to 100 percent in patients with sphincter defects. In addition, the longer-term outcome of an overlapping repair seems to deteriorate with time and some patients develop new evacuation disorders. In a study from St. Mark’s Hospital, the initial success rate of 76 percent after overlapping sphincter repair deteriorated drastically with time. After five years, no patient was fully continent to flatus and <10 percent were fully continent to solid and liquid stool.
In the acute setting, direct apposition of the anal sphincters as end-to-end repair is commonly used and
has been reported to have satisfactory results if performed adequately. Much of the poor results associated with a primary end-to-end repair occurred in the acute obstetric setting in which a sphincter repair was performed by physicians with variable expertise. In the acute setting, the tissues often are swollen, bleeding, and contaminated with liquor and feces. By contrast, most published reports of overlapping delayed sphincter repair were performed in a specialized colorectal unit in an elective setting. There are recent encouraging reports of good outcome using a direct end-to-end technique to repair the external sphincter. Poor outcome seems to be related to persistent sphincteric defects that have not been adequately repaired. This is most likely because of a failure to identify the full width of the external anal sphincter, resulting in approximation of only part of the muscle. Thus for a successful direct repair, clear visualization of the ends of the external sphincter in its entirety, as is required in overlapping repair, is essential. In addition, surgical and aseptic techniques have changed vastly in recent times and longerlasting absorbable sutures are now available, which might further favor a simpler, direct end-to-end repair. Earlier studies often used subjective assessment by surgeons without any objective data. Different clinical grading systems of fecal incontinence have made comparison of postoperative results among studies difficult. The Cleveland Clinic Continence Score used in our study assesses not only the type (solid, liquid, and flatus) and frequency of incontinence but also the impact of incontinence on the patient’s lifestyle. Some studies include patients of both genders and with both obstetric and nonobstetric causes of fecal incontinence, using a variety of surgical techniques. This unique study includes only female patients with a defined anterior defect of the external anal sphincter and evaluates the outcome after direct or overlapping repair performed by a single surgeon. In addition, patients with pudendal neuropathy as shown by a prolonged PNTML have been excluded from the study. In addition, both surgical groups were comparable with regard to age, presence of internal sphincter defect,previous sphincter repair, and the duration of follow-up. Indeed, this is the only randomized trial that directly
compares the two surgical techniques: direct end-to-end vs. overlapping repair of anal sphincters. In this study, the outcome after direct or overlapping sphincter repair was comparable clinically and
by anorectal physiologic testing. After a median follow-up of 18 months, approximately three-quarters of patients reported a persistently improved continence, although more than one-half of patients took a bulking agent at least intermittently. The continence score was substantially improved after either technique of sphincter repair. Our results are comparable with other published results on sphincter repair. We concur with others that repair of the ends of the scarred external sphincter without any excision of the scar, avoidance of hematoma, and wound infection are important aspects of a successful sphincter repair. Bowel confinement, dietary restriction, and use of a diverting stoma have not been necessary in any of our patients. As shown by others and our earlier study, the functional improvement of continence after a sphincter
repair was accompanied by an improvement of maximum squeeze anal canal pressure. The functional anal canal length also was significantly increased postoperatively in patients operated by either surgical technique. By contrast, the mean resting anal canal pressure remained largely unchanged and did not correlate with functional improvement of fecal continence after sphincter repair. Others have found that an improvement of the functional anal canal length after sphincter repair does not correspond to any improvement in resting anal canal pressure. This is in keeping with the clinical observation that control of flatus remained problematic in most patients despite good postoperative continence to solid and liquid stools. We routinely repair any defect of the internal anal sphincter within the field of surgery, en mass with the external anal sphincter. However, the role of imbricating the internal anal sphincter on restoring the anal resting pressure is not well defined. In another nonrandomized study, the outcome after a sphincter repair was similar among different
surgical techniques (end-to-end, overlapping, and plication). Failure after sphincter repair might be related to persistence or recurrence of the external anal sphincter defect as shown by endoanal ultrasound and not caused by the surgical techniques used. Endoanal sonography was not performed routinely after surgery in this study to address this issue. Impaired fecal evacuation developed in two patients after overlapping sphincter repair but was not noted in any of the patients after direct sphincter repair. Similar findings have been recently reported. This might result from the excessive mobilization of the external anal sphincter and possibly greater tension as is often required of overlapping repair. A prolonged PNTML as noted in one of our patients also might result from this excessive posterolateral mobilization of the external anal sphincter. This is particularly important because severe denervation and pudendal nerve damage often are found in patients who remained incontinent after a sphincter repair. In addition, presence of other concomitant pelvic floor dysfunction is common in this group of patients and might further complicate the results of a sphincter repair.
This study has demonstrated that anterior sphincter repair can acceptably improve fecal incontinence
when a defined anal sphincter defect is identified, as shown by patients’ assessment and by improvements in continence scores. With either surgical technique, from the median postoperative continence score of three in our study, most patients still have difficulty with control of flatus. This might reflect injury and occult muscle fragmentation of internal sphincter that is often poorly documented. Our randomized study has not shown any benefit of overlapping repair over a simpler direct repair.
After overlapping sphincter repair, there is a small, but disturbing, incidence of newly developed difficulties with fecal evacuation and a prolonged PNTML that developed postoperatively. Because these findings were not noted after direct end-to-end sphincter repair, we hypothesized that they might be related to the more extensive posterolateral dissection and mobilization as is often required in overlapping repair. If the ends of the external sphincter were not adequately mobilized, excessive tension on the overlap repair might result in evacuation difficulties. We believe that a larger multicenter, randomized, controlled trial should be conducted to further evaluate the dogma of an overlapping technique for sphincter repair. The longer-term follow-up is important and is currently in progress in our patients. |
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