Even patients with anatomic or physiologic abnormalities may benefit from maximizing medical therapy. Dietary counseling regarding diarrhea-producing foods, food intolerance, and fiber intake is virtually risk-free and may ameliorate symptoms during the workup process. We counsel most patients to maximize dietary fiber intake, including use of a bulking agent. The goal is eventual intake of 25 to 30 g of fiber daily; most patients start at levels substantially lower than this, and they should be counseled to increase their intake gradually to avoid excessive gassiness.
Selection of an antidiarrheal agent depends on the severity of incontinence. Adsorbing or coating agents are generally used for infrequent episodes. Medications that increase colonic transit time and adsorption are effective for moderate to severe symptoms. We prefer Imodium because of its combined effects on adsorption, transit time, and sphincter agonist activity. Diphenoxylate is a useful second line agent with a similar profile but more atropine-neutral side effects.
Topical sphincter agonists such as phenylephrine gel have been disappointing in randomized trials. However, novel medical therapies such as the L-erythro methoxamine isomer are in development and may prove more effective (Parker et al,2003).
For alternating diarrhea and constipation conditions, such as irritable bowel syndrome or overflow incontinence due to obstipation or spinal cord injury, we recommend a bowel management regimen. We start with rectal disim-paction and a whole bowel cathartic, such as polyethylene glycol, followed by regular laxatives combined with suppositories or enemas if necessary.
Biofeedback therapy confers the distinct advantage of a noninvasive intervention that is safe, that allows (requires) active patient participation, and that may enhance the effects of other treatments (Jensen and Lowry, 1997). Patients perform anal sphincter contraction exercises and receive computerized visual or auditory responses; thus, they learn muscle control by means of sensory feedback. Anorectal biofeedback therapy specifically aims (1) to augment external anal sphincter function, resulting in successful voluntary delay of defecation, (2) to improve rectal sensation, thereby alerting patients to the presence of stool in the vault and the need for voluntary sphincter contraction, and (3) to coordinate sensation and contraction, thereby overcoming reflexive relaxation in the presence of rectal contents (Loening-Baucke, 1990).
We use a two-channel electromyography electrode with one sensor placed in the anal canal and the other surface electrode placed on the gluteus muscles for strength and endurance training. Patients practice maximum squeeze and muscle isolation in the upright position, which facilitates coordination training and enhances feedback. When patients demonstrate adequate understanding and ability to perform exercises, they are assigned to continue strength training at home, using gradually increasing daily exercises. We have found that patients relearn sensitivity to smaller filling volumes and sensation improves without formalized training.
A trained, dedicated, and sensitive therapist is essential in biofeedback therapy. To qualify for biofeedback therapy, patients must be capable of the required cognitive function and have some degree of rectal sensation and of external anal sphincter function. Despite a lack of a standardized biofeedback method, outcomes have been highly encouraging. Pager and colleagues (2002) recently reported long term results for 83 incontinent patients who completed a 4-month biofeedback training program. At a median of 42 months, patients demonstrated ongoing significant improvements in all outcome measures; many improved further after completing the program. However, a recent randomized controlled trial of biofeedback versus standard conservative therapy failed to show a difference between these approaches (Norton et al, 2002). This finding calls into question the exact role of biofeedback itself and emphasizes the importance of ancillary therapy (such as dietary counseling and drug therapy) in the conservative management of incontinent patients. We have seen substantial clinical improvement in our biofeedback patients (Jensen and Lowry, 1997), but a decline in function may occur over time. We have found that performance may be bolstered by intermittent supplementary training sessions.
Traditionally, surgical intervention has been based on the following two simple underlying concepts: (1) introducing mechanical obstruction, via encirclement with native or prosthetic materials, or (2) decommissioning the anorec-tum, via creation of a diverting stoma. Sphincteroplasty, historical and novel encirclement methods, and interesting new techniques still under investigation are discussed below.
Sphincteroplasty For incontinent patients with a sphincter defect, our initial intervention is usually overlapping sphincteroplasty. With the patient in prone jackknife position, we sharply dissect the internal and external sphincters, mobilizing for an overlapping plication. An anterior leva-toroplasty can be performed to lengthen the anal canal at the discretion of the surgeon; some advise against leva-toroplasty because it may contribute to postoperative dys-pareunia. Significant improvement in continence with minimal morbidity is achieved in approximately 70% of patients who undergo sphincteroplasty. Recent data, however, suggest that the results of sphincteroplasty deterio-ratewith time.We reviewed our long term (median 10 years) results of overlapping sphincteroplasty in 191 consecutive patients and found that only 40% of patients maintained long-term continence (Baxter et al, 2003). Older patients were more likely to develop recurrent incontinence to solid stool. Surprisingly, despite the deterioration of continence with time, 74% of patients still stated that they were satisfied with their treatment at 10 years postoperation.
Encirclement Procedures The concept of circumferential anal sphincter support began in 1891 with the Thiersch wire, a silver wire tunneled subcutaneously around the external anal sphincter. Because of a high rate of local complications, this technique is now of historical interest only. Both dynamic graciloplasty and the artificial bowel sphincter work on the same principle as the Thiersch wire; in contrast, however, these newer techniques each work dynamically to permit both closure and relaxation of the anal canal.
Dynamic Graciloplasty. Encirclement using native muscle has been a trial-and-error process. Both gracilis and gluteus maximus wraps have been used. From the technical perspective, the gracilis is well suited for transposition because of its proximal neurovascular bundle, superficial location, and lack of important function in humans. The muscle is mobilized, tunneled subcutaneously in the upper thigh, and wrapped around the external sphincter. The muscle works largely as a passive barrier, though some contraction is possible by adduction of the leg. In an effort to improve the functional results of graciloplasty, electrical stimulation is applied to convert from fast-twitch, fatigue-prone fibers to slow-twitch, fatigue-resistant fibers over an 8-week period. After 8 weeks, the neosphincter muscle is maintained in tonic contraction, except when the implanted pulse generator is magnetically deactivated.
Outcomes of dynamic graciloplasty are mixed. Although approximately two thirds of patients who undergo the procedure achieve successful results (Madoff et al, 1999), complication rates have been prohibitively high. Accordingly, the technique remains available in a small number of highly specialized centers worldwide, but is not approved by the Food and Drug Administration for use in the United States.
Artificial Anal Sphincter. The artificial anal sphincter (Acticon Neosphincter, American Medical Systems, Minnetonka, MN) consists of a silicone elastomer cuff tunneled around the external anal sphincter. The cuff is connected to a pump in the labia or scrotum, with a reservoir balloon placed in the preperitoneal space (Figure 88-1).
Repetitive compression of the pump causes fluid efflux from the cuff to the balloon, allowing rectal evacuation, followed by slow return of fluid from the balloon to the cuff.
A multicenter trial of the artificial anal sphincter ended recently, with results somewhat similar to those for dynamic graciloplasty (Wong et al, 2002). Success was defined as a decrease of at least 24 points on the Fecal Incontinence Scoring System designed for that trial (range 0 to 120 points). In all, 46% of patients required reoperation, primarily because of infection; 37% required device explantation, 20% of whom were reimplanted with a new device. In patients with a functioning device, 85% achieved continence; the success rate was only 53%, however, if all treated patients were included in the calculation. The artificial anal sphincter has now been approved by the Food and Drug Administration in the United States.
Although neosphincter outcomes may appear less than encouraging at first glance, one must remain mindful that these are patients with substantial incontinence who have failed or are not candidates for standard therapy such as sphincteroplasty or biofeedback. For either neosphincter procedure (ie, dynamic graciloplasty or the artificial anal sphincter), patient selection should be based on the presence of severe incontinence refractory to other therapy, otherwise good performance status, adequate cognitive ability, and psychological stability. Trained practitioners who reserve these treatments for appropriate patients under rigorously controlled conditions can have an extremely positive impact on their patients' quality of life (Madoff et al, 2000). Furthermore, among our patients at the University of Minnesota with established artificial sphincters, full functioning has been ongoing for several years postimplantation (Parker et al, 2003).
Neuromodulation Sacral nerve stimulation (SNS), initially developed for urinary incontinence, represents a departure from previous models of fecal incontinence therapy. Instead of correcting or replacing defective morphology, this treatment aims to augment physiologic function by recruiting and stimulating S2, S3, or S4 nerves as they exit the sacral foramina. The three-part procedure begins with placement of a subcutaneous electrode in the sacral foramina to identify the site of maximal pelvic floor and minimal lower extremity stimulation. Next, the lead is connected to an external pulse generator for a 3-week test period. After 3 weeks, if functional improvement is adequate, we implant a permanent pulse generator (Figure 88-2).
Initially, the consistent reduction in incontinent episodes was attributed to electrical recruitment of striated muscle fibers in the pelvic floor and external sphincter (Matzel et al, 1995). More recent data suggest other possible mechanisms of action, including improved rectal sensation, enhanced resting anal tone, alteration in local reflexes, and dampening of rectal activity. Kenefick and colleagues (2002)
FIGURE 88-2 Radiograph of an implanted sacral nerve stimulator device. Courtesy of Robert D. Madoff, MD.
recently reported excellent results; at a median of 2 years, 73% of previously incapacitated patients achieved full continence; symptoms markedly improved for the others. Unlike the neosphincter procedures, SNS has been associated with minimal morbidity. This fact suggests that indications for the procedure might reasonably be broadened, at least on an investigational basis, in the future.
Radiofrequency Energy Delivery Submucosal radiofre-quency energy delivery to the anal canal (also known as the Secca procedure) is a thermal technique currently under investigation in a multicenter trial. The procedure consists of anal insertion of a heat-controlled probe. The probe then deploys electrodes that pierce the mucosa and heat the muscularis, resulting in collagen contraction. However, the exact mechanism of action using this technique is unknown. Early results have shown modest improvement in incontinence severity.
Anal Canal Bulking and Obstructing Agents In contrast to stool bulking agents, anal canal bulking agents are made of implanted natural or synthetic materials, such as collagen, silicone, or carbon coated beads, that are injected into the intersphincteric space to bolster function of the internal anal sphincter. We do not perform this procedure, although good outcomes in very small series have been reported. Obstructing agents, such as pliable rubber balloons, are placed in the anus; they can be removed by the patient for controlled defecation (Norton and Kamm,
2001; Mortensen and Humphreys, 1991). Such an intervention might be useful for patients who are at very poor risk for surgery.
Stoma For patients with refractory incontinence, a properly placed and well-constructed stoma offers restoration of bowel control (if not true continence) with minimal associated morbidity. Although the presence of a stoma admittedly distorts an individual's body image, this disadvantage is usually outweighed by the patient's enhanced ability to function normally (or nearly so) in social, work, and sexual situations without fear of loss of bowel control.
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