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19 Manometric Squeeze Pressure Difference Parallels Functional Outcome After Overlapping Sphincter Reconstruction [2001년 5월 DCR] 2011-11-17 3216
 
Hannah T. Ha, M.D., James W. Fleshman, M.D., Mama Smith, M.D.,Thomas E. Read, M.D., Ira J. Kodner, M.D., Elisa H. Birnbaum, M.D.
 
From the Section of Colon and Rectal Surgery, Department of Surgery, Washington University School of
Medicine, St. Louis, Missouri
 
PURPOSE: This study was designed to evaluate the effectiveness of overlapping anal sphincter reconstruction and to determine the manometric parameters that correlate with a successful functional outcome.
METHODS: A retrospective review of patients who had undergone overlapping sphincter
reconstruction for anal incontinence from 1988 to 1999 was undertaken. Only patients with preoperative and sixmonths-postoperative anal manometry were included in this study. Standard statistical tests were used to compare pre- and postoperative findings.
RESULTS: A total of 52 overlapping sphincter reconstructions were perfomaed on 49 patients (46 females). The mean age was 44 (-+ standard error, 15.8; range, 20-81) years, with follow-up at six
months. Forty-two patients had a history of complicated vaginal delivery (episiotomies, tears, forceps delivery); 36patients had a history of anal or perineal surgery; and two patients had perianal Crohia's disease. Nine patients (17 percent) had undergone prior sphincter repair. Incontinence grade improved in 37 patients (71 percent), and complete continence returned in 21 patients (40 percent). The presence of a rectovaginal fistula, postoperative complications, previous sphincter repair, and increase in pudendal nerve terminal motor latency did not affect functional outcome (P = not significant). Patients older than 50 years had a better functional outcome than their younger counterparts after sphincter repair (P = 0.02). Although mean maximal squeeze pressure and mean anal sphincter length increased significantly after sphincter reconstrtmtion (P = 0.0006 and 0.004, respectively), only squeeze pressure difference correlated with functional outcome (r = 0.37; P = 0.007).
CONCLUSIONS: Overlapping sphincter reconstruction improved anal ftmction in the majority of patients. The most important factor in the return to normal sphincter function is an increase in squeeze pressure.
 
Fecal incontinence is a condition frequently encountered in surgical practice) Although the majority of patients with anal incontinence are elderly females with a remote history of obstetric injury, patient
profiles and etiologic factors can be variable. Anal sphincter reconstruction can restore continence
in the majority of affected patients, significantly enhancing their quality of life. The use of objective tests including anal manometry, pudendal nerve terminal motor latency (PNTML), and endoanal ultrasound (EAUS) to predict those patients who will benefit from sphincter reconstruction has been reported. The exact relationship between anal manometric data and symptoms of incontinence is difficult to establish, and the utility of routine manomett T in patients with anal incontinence has been questioned. We undertook the current study to better understand the role of pre- and postoperative anal manometry in predicting the functional outcome of patients undergoing overlapping anal sphincter reconstruction (OASR).
 
DISCUSSION
We demonstrated that overlapping sphincter reconstruction improves fecal incontinence in the majority
of patients. Our success rate of 71 percent compares favorably to the results reported by 0thers. Complete continence was achieved in 40 percent of the patients at the six-month follow-up. In a previous study, we evaluated 28 patients with anal incontinence caused by obstetric injury. Anal function was improved in 96 percent of patients relative to their preoperative symptoms, and complete control of continence was observed in 54 percent of patients. We then analyzed patients in our present study who had anal incontinence caused only by obstetric injury and found that functional improvement was achieved in 74 percent of patients with a complete continence rate of 38 percent. The discrepancy between the two studies may be explained by the follow-up interval of patients' anal function. In our present study, we reviewed the office and hospital charts for patients' grade of incontinence at six months after sphincter repair, whereas, in the previous study, grade of incontinence was obtained by patient contact at the time of the study. Therefore, patients' follow-up in our previous study may have been longer than six months, and anal sphincter function may continue to improve with longer foUow-up. Although deteriorating results after overlapping sphincter repair for obstetric injury with longer follow-up has been reported, a follow-up of our study is warranted to evaluate the long-term effect of sphincter reconstruction.
 
The manometric changes after sphincter reconstruction appear variable by report. We found that squeeze pressures and sphincter length increased significantly after sphincter reconstruction whereas resting pressures did not. In the previous study, we reported increases in resting and squeeze pressures and sphincter length after sphincter repair; however, squeeze pressure and anterior sphincter length increased by a greater degree. Ternent et al found no significant changes in anal manometry after sphincter repair, whereas Londono-Schimmer and colleagues found a significant improvement in squeeze pressures but not resting pressures. Anal sphincter length was not evaluated in that study. Whether the differences in manometric findings reported by various groups are the result of differences in technical aspects of surgery or manometry is unclear.
 
Although squeeze pressures and sphincter length increased significantly after surgery in our study, only
the squeeze pressure difference correlated with functional outcome as measured by changes in grade of incontinence. In an OASR, the external anal sphincter, which is responsible for squeeze pressures, the internal anal sphincter, which is responsible for resting pressures, and scar tissue are reapproximated to restore and lengthen the anal sphincter complex. Therefore, squeeze pressures, resting pressures, and sphincter len~h should increase with this procedure. Only increases in squeeze pressure and sphincter length were achieved in our study. We also found that the only manometric parameter that correlated with changes in grade of incontinence after an OASR was the squeeze pressure difference. In contrast, Wexner et al showed that an increase in resting pressures, squeeze pressures, and sphincter length correlated well with functional improvement. Likewise, Fleshman et al showed that complete control of continence was associated with restoration of normal resting pressure, squeeze pressure, and anal sphincter length. However, the most important manometric parameter
in the restoration of incontinence appeared to be squeeze pressure. A recent study showed that
postoperative sphincter length was the most significant predictor of postoperative continence, a The technique that was used in that study was more stringent, defining the anal canal where the resting pressure was greater than 20 mmHg in all quadrants, and may explain the level of significance found. Although the external anal sphincter also contributes to 20 percent of the resting pressures, the lack of increase in resting pressures and the correlation with anal functional outcome after sphincter repair in our study suggest that other factors may contribute to the restoration of resting pressure.
 
Patients' age at the time of sphincter repair correlated with functional outcome in our study. Patients
older than 50 years were more likely to have an improvement in continence status than younger patients,
despite comparable preoperative grades of continence. However, improvement in continence status was not observed in patients older than 60 or 70 years and may be explained by the small number of patients over those ages (11 patients and six patients, respectively). The effect of age on functional outcome
reported by others has been mixed. Although some reports found no correlation between age and postoperative function, others conclude that failure rates are higher with increasing age.Simmang et al
found that functional outcome after sphincter reconstruction in the elderly, as defined by age over 55
years, was comparable to that in younger patients. We evaluated various parameters including a history of prior anorectal surgery, delivery complications, and manometric results (resting pressure, squeeze pressure, and sphincter length before and after repair) and found no differences between the two age groups. The significant improvement in functional outcome in the older group may be explained by factors that were not measured in our study, such as hormonal replacement, fatigue rate index, and rectal adaptation. Our findings suggest that advanced age should not be an exclusion criterion in evaluating patients for sphincter reconstruction.
 
Prolonged pudendal nerve latency did not affect functional outcome in our study. However, only four
patients were found to have prolonged nerve latency preoperatively, and statistical significance may not be reached with the small number of patients. In addition, patients may be preselected to undergo a
sphincter reconstruction based on preoperative nerve studies. A relationship between neuropathy and
functional outcome has been extensively reported. Patients with pudendal neuropathy were more
likely to fail after an overlapping sphincter repair in some studies, whereas others argue that the presence of neuropathy was not predictive of a poor outcome. A trend toward less improvement in fecal
continence was noted with bilateral pudendal neuropathy] Although our study is limited, our findings
suggest that the presence of prolonged pudendal nerve latency should not preclude the patient from a
sphincter reconstruction.