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102 Artificial Bowel Sphincter [2003년 6월 DCR] 2011-11-17 3334
 
Long-Term Experience at a Single Institution
 
Susan C. Parker, M.D.,* Michael P. Spencer, M.D.,* Robert D. Madoff, M.D.,*Linda L. Jensen, R.N.,* W. Douglas Wong, M.D.,† David A. Rothenberger, M.D.*
 
From the Departments of Surgery, *University of Minnesota, St. Paul, Minnesota, and the †Memorial
Sloan-Kettering Cancer Center, New York, New York
 
PURPOSE: This study was undertaken to evaluate a singleinstitution experience with the Acticon® artificial bowel sphincter for the treatment of intractable fecal incontinence.
METHODS: At the University of Minnesota, 45 consecutive patients underwent artificial bowel sphincter
placement (Group I, 1989–1992, n = 10; Group II, 1997–2001, n = 35). Group I was reviewed retrospectively and Group II prospectively.
RESULTS: The outcome for Group I patients was initially reported in 1995 (mean age, 32; range, 15–52 years; 7 males). Of these 10 patients, 4 required explantation (2 required stomas), and 6 have a functional artificial bowel sphincter; 2 patients had devices successfully replaced for fluid leaks (at 6 and 10 years). In Group II, artificial bowel sphincter placement was attempted in 37 patients and was successful in 35 (mean age, 47; range, 18–72 years; 11 males). A total of 14 patients required
explantation, 12 (34 percent) for infection and 2 (6 percent) for pain. In total, 13 patients have required 21 revisions, including 7 complete device replacements. The infection rate for revisions was 19 percent; four patients required explantation after revisions. Of 18 patients whose artificial bowel sphincter failed, 9 required a stoma. In all, 17 (49 percent) patients have a functional artificial bowel sphincter. In Group II fecal incontinence severity scores decreased from a mean of 103 preimplant to 59 at one year and to 23 at two or more years (P < 0.001) in patients who retained their devices. Quality of life scores improved in all patients at six months and at one year (P < 0.01).
CONCLUSION: Artificial bowel sphincter therapy leads to longterm improved continence and quality of life in patients whose implantation is successful. Success rates have not improved in the two patient groups, with infection remaining a major challenge. However, once successfully established,artificial bowel sphincter function remains stable for many years.
 
Fecal incontinence, a distressing condition that often leads to social isolation, affects a surprisingly
high percentage of adults. A U.S. study of ambulatory patients found an overall prevalence of 18.4 percent. The prevalence was doubled for patients visiting a gastroenterologist (26 percent) vs. those
seeing a primary care physician (13.4 percent). The U.S. data, when stratified by frequency of episodes,
showed that 2.7 percent of patients had incontinence daily, 4.5 percent weekly, and 7.1 percent monthly.
The prevalence of fecal incontinence among Canadian and U.S. nursing home patients is at least 46
percent.
 
The level of treatment must be appropriate for the severity of symptoms. Nonsurgical techniques (such
as biofeedback, bulking agents, and constipating medications) are appropriate for patients with minor
degrees of incontinence. Patients with recognizable predisposing conditions (such as sphincter disruption or rectal prolapse) benefit from the appropriate surgical therapy. Patients with intractable, clinically significant fecal incontinence, caused by the failure of recognized therapies or the severity of anatomic abnormalities (traumatic or congenital), should be considered for an innovative technique or a stoma.
 
Innovative techniques include the artificial bowel sphincter (ABS; Acticon®, American Medical Systems,
Minneapolis, Minnesota), sacral nerve stimulation, and dynamic graciloplasty
. Christiansen et al. first
reported successful implantation of an ABS for fecal incontinence in 1987. Subsequently, Lehur et al. and Wong et al. also reported successful use of the modified urinary sphincter (AMS800, American Medical Systems) for fecal incontinence. All three reports cited significant infection rates and technical problems; however, with revisions, ultimate success was achieved in more than one-half of the patients.
 
The cuff size, cuff design, and reservoir balloon size of the early ABS version were modified to address
technical problems particular to use of an occlusive cuff around the anal canal. The modified ABS was
reintroduced to the market in 1996 (Acticon® Neosphincter, American Medical Systems). Recently,
the results of a multicenter, prospective, clinical trial (IDE G960116) conducted from 1997 through 2001 were published. In that trial, the device was implanted in 112 patients at 19 sites in the United States,
Europe, and Canada. Despite a high morbidity rate and the need for revisional surgery in 51 (46 percent)
of the patients, 85 percent of the patients with a functioning device had a successful outcome.
 
In the Division of Colon and Rectal Surgery, Department of Surgery, at the University of Minnesota,
we have treated patients with intractable fecal incontinence with dynamic graciloplasty, sacral stimulation, and the ABS. In 1989, we began implanting the early version (AMS800) of the ABS; that experience was reported by Wong and colleagues in 1997.9 In 1996, we began using the modified version (Acticon®Neosphincter). We here present our long-term experience with the use of the ABS for intractable fecal incontinence.
 
DISCUSSION
As with the multicenter clinical trial of the Acticon®Neosphincter, which included early results on 26 of
our patients, we experienced a high infection and erosion rate (34 percent) after initial device placement.
Revisional surgery was necessary for an additional 37 percent of our patients. Our success rate was
similar to that of other studies with long-term followup. 8 Although our success rate was only 49 percent
(intention-to-treat success rate 47 percent) for Group II, our functional success rate in patients who retained their device was 88 percent at one year and 100 percent at two years or more. The criterion of at least a 24-point drop in the FISS used for the multicenter trial to define functional success was easily met by an average drop in our implanted patients of 54 points at one year and 90 points at 24 months or more. Such patients may then experience unaltered function, as evidenced by Group I patients whose devices have functioned for more than ten years. This is further illustrated by the two patients presenting at six and ten years after implantation with recurrent incontinence because of fluid leaks. They subsequently underwent successful reimplantation, and had restored continence.
 
We attempted placement of an Acticon® Neosphincter in five extremely challenging patients: two with hemipelvectomies and three who first required gluteal rotational skin advancement flaps for perineal
reconstruction. We successfully placed devices in two of the three patients with gluteal flaps. This technique may be preferable for patients with severe perineal trauma because it restores soft tissue to the area and allows high placement of the perianal cuff. Both of our patients with hemipelvectomies experienced device failure because of erosion.
 
It is unlikely that revisional surgery can be avoided completely, but several measures may decrease the
need. Pump revisions require placement of a new pump in a new subcutaneous pocket, usually on the
opposite side. We placed a new pump into the original subcutaneous location in three patients. Despite
attempts to secure the new pump in the old location with sutures, pump migration occurred, necessitating a second operation to place a new pump on the opposite side. An unbuttoned cuff is an indication that a smaller cuff size is needed. When we first encountered a patient with incontinence and an unbuttoned cuff, we assumed the problem was caused by a technical error, so we rebuttoned the cuff. Subsequent cases of loose or unbuttoned cuffs were successfully treated with cuff replacements, using a smaller-size cuff. The manufacturer also altered the tab design of the cuff to further decrease the possibility of cuff unbuttoning. Tissue shrinkage, noted in patients with loose cuffs and incontinence, will inevitably require cuff replacement.
 
Compared with dynamic graciloplasty, the ABS is technically easier to place, carries a similarly high
reoperation rate, and avoids substantial morbidity. It may also provide a better functional result. A multicenter trial of the dynamic graciloplasty found a 63 percent success rate (defined as a 50 percent improvement in incontinent events). Dynamic graciloplasty is available in Canada and Europe but
not in the United States, because Food and Drug Administration approval was not sought in this country.
In our study and in the multicenter ABS trial, an 85 to 88 percent functional success rate in patients with
an operational device was defined as a drop of at least 24 points in the continence score. In our study the average drop was more than 50 points at one year and 90 points at two years. Thus, patients previously incontinent daily are now continent to liquids and solids. Dynamic graciloplasty remains an option, particularly for patients without sufficient perineal soft tissue; perineal reconstruction, however, is also possible in conjunction with ABS placement.