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| 번호 | 제목 | 등록일 | 조회수 |
|---|---|---|---|
| 39 | Clinical Rather than Laboratory Assessment Predicts Continence After Anterior Sphincteroplasty [2001년 9월 DCR] | 2011-11-17 | 3476 |
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W. Donald Buie, M.D., Ann C. Lowry, M.D.,David A. Rothenberger, M.D., Robert D. Madoff, M.D.
From the Deparlment of Surgery, Division of Surgical Oncology, University of Calgary, Calgary, Alberta,
Canada, and the Department of Surgery, Division of Colon and Rectal Sugery, University of Minnesota, St. Paul, Minnesota PURPOSE: Preoperative anorectal physiology studies have become part of' the standard evaluation of fecal incontinence. This study was undertaken to see whether anorectal physiology results predicted surgical outcome after anterior sphincteroplasty.
METHODS: Between 1985 and 1994, 191 females with a mean age of 37 (range, 20-74) years underwent
anterior sphincteroplasty for anal sphincter disruption. A follow-up questionnaire was sent to all patients, and there were 158 respondents (83 percent). Mean follow-up was 43 (range, 6-120) months. Obstetric injuries accounted for incontinence in 91 percent of the 158 patients who responded to the questionnaire. Mean duration of incontinence was 4.2 years (range, 3 months-51 years) before surgeD,. Preoperatively, patients were incontinent to solid stool (53 percent), liquid stool (33 percent), gas (3 percent), and unspecified (11 percent). RESULTS: Subjectively, the results were as follows: 129 patients (82 percent) improved, 17 (11 percent) were initially improved but subsequently deterioratcd, 7 (4 percent) were unchanged, and 5 (3 percent) were worse. Objectively, postoperative continence was classffied as follows: excellent (normal) in 23
percent, good (incontinent to gas or minor stain) in 39 percent, fair (incontinent to stool an average of less than once per month) in 26 percent, and poor (incontinent to stool an average of greater than once per month) in 12 percent. Preoperative continence level (incontinent to solid vs. liquid stool) was predictive of postoperative continence classification. Preoperative anorectal manometry was not predictive of clinical outcome (n = 128). There was no significant difference in postoperative continence classification among patients with normal, unilaterally abnormal, and bilaterally abnormal pudendal latency (n = 89). CONCLUSIONS: Clinical rather than manometric assessment predicts continence after anterior sphincteroplasty.
Anterior sphincteroplasty is the primary method for late repair of traumatic sphincter defects. It provides good to excellent results in most patients with a well-defined sphincter disruption and adequate
residual muscle mass. Patients with an anterior sphincter defect from obstetric or operative trauma or accidental impalement injuries are best suited for this type of repair. There is some evidence that patients with obstetric trauma can expect better results. 3'4 On examination the sphincter mechanism should be anatomical]y intact except for the area of injury, and there should be palpable contraction of the remaining muscle mass. All suppuration should be quiescent, and there should be no evidence of inflammatory bowel disease in the anorectum. Many patients undergo anorectal physiology studies before repair to assess pudendal nerve function
and residual muscle function in an effort to predict the results of surgical repair. The predictive value of these tests, however, remains in question. The aim of this study was to evaluate the ability of anorectal physiology studies to predict clinical outcome after anterior sphincteroplasty. DISCUSSION
Of the numerous studies published recently, most are small with variable lengths of follow-up. Comparison is difficult because of the lack of a universally accepted continence score and the variable interpretation of what constitutes a good result. There is no difficulty in identifying patients who are completely incontinent to liquid and solid stool; nor is there difficulty identifying patients who are completely continent. However, most patients can expect results that are between these two extremes. A validated quality of life questionnaire for patients with fecal incontinence has now been developed
by- The American Society of Colon and Rectal Surgeons, and its adoption, along with a validated scoring system for incontinence severity, may permit a more reliable assessment of patient outcome. Patients in this study were asked to rate their level of satisfaction with their results subjectively. Table 6
shows the results as they relate to continence classification. Not surprisingly, satisfaction correlates inversely with a poor result. What is surprising is that 32 percent of patients with what we defined as a poor result are satisfied. This implies either that the scoring system does not accurately categorize patient outcome or that patients and physicians have different expectations after surgery for incontinence. It is also possible that patients sought to minimize their symptoms in hopes of not clisappointing or antagonizing their surgeon. All of these factors contribute to the observed discrepancies. Thus, expressed patient satisfaction after incontinence surgew is not solely dependent
on the level of postoperative continence. A review of the largest series of anterior sphincteroplasties (greater than 30 patients) published since
1985 is compiled in Table 7. These combined results closely parallel our own results. Most authors attempt to identify retrospectively the clinical and laboratoi T criteria that will reliably predict
postoperative results. In previous studies, older patients and patients with longer duration of incontinence have been associated with poorer results. Neither of these associations were seen in. the present study. Many authors feel that age is not a specific contraindication for repair although a recent study by Rasmussen et el. suggested improved results in patients under 40 years of age. Preoperative incontinence level has been previously identified as predictive of postoperative continence level, which was confirmed in the present study. Although the level of preoperative incontinence does not identify the exact physiologic abnormality, it may serve to give a global assessment of previous sphincter and pelvic floor damage. Previous repairs are also thought to be a predictor of poor results. Surgical mobilization inevitably
causes some devascularization and further scarring of the sphincter muscle. Although anatomic reconstruction is possible, an improvement in function may not follow because of loss of muscle tissue. On the other hand, several studies have shown that inadequate muscle overlap with a residual gap is a major cause of failure after overlapping sphincteroplasty. Investigation with ultrasound and reoperation with successful anatomic reconstruction will give a good functional result in most cases. It is impossible to draw any definitive conclusions about patients with a previously failed sphincteroplasty in this study because very few patients had a preoperative ultrasound. More objective criteria have been sought in the anorectal physiology laboratory because clinical parameters are variable in their predictive ability. Anorectal manometry has been performed in all of the
large studies. Although some studies suggest that manometry is predictive of postoperative results, the majority including the present study have not found this to be the case. A documented increase in squeeze pressure and sphincter length seems to be correlated with an improvement in continence. The exact measurement of the latter is very subjective and difficult to reproduce. The relationship between pudendal neuropathy and outcome of sphincteroplasty is controversial (Table 8). Pudendal neuropathy has correlated with poor result, s in some studies but not in others. Gilliland and colleagues recently found bilateral normal PNTML to be the only factor predictive of long-term success after overlapping sphincteroplasty. Of the remaining studies in which association is reported, two are small and four pre.sent conflicting data from the same institution. Two small studies have also indicated that bilaterally prolonged pudendal nerve conduction may be more important than a unilateral abnormality. In the present study, PNTML did not predict clinical outcome. Excellent and good results occurred in 60 percent of patients with normal PNTML and in 68 percent of patients with unilaterally prolonged PNTML.
Although it makes intuitive sense that abnormal innervation of the external sphincter complex would
lead to compromised function, there are several reasons why clinically measured PNTML may not correlate with functional outcomes of surgery. First, normal pudendal nerve latencies do not exclude nerve damage. PNTML measures the conduction time of the fastest remaining nerve fibers and thus does not quantify the amount of nerve damage. In addition, there is evidence of anatomic overlap in pudendal nerve innervation for both sides of the external anal sphincter. The two nerves may not innervate the sphincter symmetrically, and thus unilateral damage may cause a greater deficit in certain patients. Finally, normal values for PNTML are not clearly established. Many laboratories have not established their own range of normal based on testing a control population, and they rely on the initial criteria set out by the St. Mark's group. Inexplicably, the cutoff for this group of patients was set at one rather than two standard deviations from the mean. It remains possible that, above a certain value, PNTML becomes predictive of a poor surgical outcome. Two patients in our series had a bilaterally unrecordable PNTML, and both of these had poor results. |
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