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7 Rectal Augmentation and Stimulated Gracilis Anal Neosphincter [2001년 2월 DCR] 2011-11-12 3235
 
A New Approach in the Management of Fecal Urgency and Incontinence
Norman S. Williams, M.S., F.R.C.S., Olagunju A. Ogunbiyi, M.D., F.R.C.S.,
S. Mark Scott, P h . D . , Olu F a j o b i , M.Sc., F.R.C.S., Peter J. Lunniss, M.S., F.R.C.S.
From the Academic Department of Surgery, St. Bartholomew's and The Royal London School of Medicine and Dentistry, The Royal London Hospital, London, United Kingdom
 
PURPOSE: The aim of this study was the development of a procedure which would successfully treat selected patients presenting with incapacitating urgency and fecal incontinence. Some patients presenting with urgency and fecal incontinence, with an intact anorectum but deficient sphincter mechanism, have low rectal compliance. Management is problematic, because correction of the sphincter defect does not abolish the incapacitating urgency caused by rectal hypersensitivity. METHODS: This was a prospective study of three female patients with urgency and fecal incontinence who underwent combined rectal augmentation using a segment of distal ileum and stimulated gracilis
anal neosphincter. All patients had low rectal volumes and two exhibited a temporal relationship between high-amplitude (>60 mmHg) rectal pressure waves and urgency on prolonged ambulatory anorectal manometry.
RESULTS: Urgency was abolished and continence restored in all individuals. When the level of stimulation was not optimal or had been discontinued, patients experienced only passive incontinence
with no urgency. Postoperative physiology revealed elevated thresholds to rectal distention and a reduction in the number of high-amplitude rectal pressure waves in all cases.
CONCLUSIONS: Combined rectal augmentation with stimulated gracilis anal neosphincter may be of benefit to some patients with distressing urgency and fecal incontinence not previously helped by current techniques.
 
DISCUSSION
Augmentation of rectal capacity using a segment of ileum was first described by Kock et al. when they
devised the modified rectal bladder (the augmented and valved rectum) as a viable alternative to the urinary bladder in cystectomized individuals. Studies in dogs and humans produced a compliant low-pressure reservoir in which the rectal capacity was increased four-fold to five-fold. We have used this novel technique in three selected patients with urgency of defecation and fecal incontinence in an attempt to abolish the sensation of urgency. This is the first time to our knowledge that the technique has been used for this problem.
 
The cause of severe urgency of defecation is often muhifactorial and in some cases is unknown. In this
study all patients had evidence on physiologic testing of reduced thresholds to rectal distention. In two
patients, high-amplitude rectal pressure waves were also present on ambulatory manometry, coincident
with their symptoms of urgency. These abnormalities may have been caused by direct operative damage to the rectum in one case (Patient A). The second patient (Patient C) had developed symptoms after a laminectomy for a prolapsed intervertebral disc, and presumably her symptoms were neurogenic in origin. All patients also had severe sphincter deficiency. The operation was therefore tailored to the physiologic abnormalities. Thus the side-to-side anastomosis of the ileal segment increased rectal capacity, and the graciloplasty augmented the anal sphincter. The postoperative investigations demonstrated that the operation had achieved these objectives: rectal distention thresholds were elevated to within normal limits, squeeze pressures were raised in all patients, and high-amplitude rectal waves and other parameters of rectal motility were attenuated. To achieve augmentation of the rectum it was necessary to divide the circular and longitudinal muscle layers in a vertical direction. This may have abolished the propagation of the high-pressure, propulsive waves detected preoperatively
in two patients. However, it is too early to advocate patient selection solely on this physiologic finding, because one of the three patients had normal ambulatory physiology.
 
It could be argued that correction of the sphincter deficiency by construction of the neosphincter alone
might have eliminated the sense of severe urgency experienced by these patients. However, urgency of
defecation was completely abolished in all patients after stoma closure, even when the neosphincter was not stimulated. Furthermore, one patient (A) complained of severe urgency despite having a
neosphincter constructed; this was only relieved after subsequent rectal augmentation. It might also be considered that neosphincter formation was not required in such patients and that rectal augmentation alone would have been sufficient. This is unlikely, because although urgency was abolished postoperatively, the patients experienced passive incontinence when the neosphincter was not stimulated.
The operation of rectal augmentation is akin to clam cystoplasty or bladder augmentation by enterocystoplasty performed by urologic surgeons for patients with severe detrusor instability or small-capacity bladders. The aim for such patients is to increase bladder volume and reduce the dysmotility of the vesical smooth muscle. Numerous publications attest to the effectiveness of this procedure. 25 One complication that may occur after cystoplasty is an inability to void urine postoperatively. This problem is, however, relatively easy to surmount by self-catheterization. If a similar difficulty arose after rectal augmenration, patients would have to resort to aperients and enemas. This occurred in one patient, although it is difficult to ascribe this to augmentation alone, because rectal evacuatory problems of varying degrees occur in up to 40 percent of neosphincter patients.
Augmentation could have been achieved by use of a segment of colon. We elected to use small intestine because of technical ease and because we did not wish to interfere with motility patterns in the large bowel, which might have resulted from transection, anastomosis, and autonomic denervation as a result of mobilization.
The new operation of rectal augmentation addresses the rectal hypersensitivity component of fecal
incontinence not previously considered. The results in this small group of patients are encouraging.
Clearly this new approach needs further study. One important aspect of future study will be to determine
whether the procedure is indicated in patients without concomitant neosphincter construction. As in all
preliminary reports, we recognize that a larger study with longer follow-up is needed and might bring to
light unanticipated complications. Nevertheless, we are cautiously optimistic that rectal augmentation will benefit some patients with distressing rectal urgency not previously helped by current techniques.