Reassessing artificial bowel sphincters

Challenges faced in the clinical application of artificial anal sphincters

Fecal incontinence is an unresolved problem, which has a serious effect on patients, both physically and psychologically. For patients with severe symptoms, treatment with an artificial anal sphincter could be a potential option to restore continence. Currently, the Acticon Neosphincter is the only device certified by the US Food and Drug Administration. In this paper, the clinical safety and efficacy of the Acticon Neosphincter are evaluated and discussed. Furthermore, some other key studies on artificial anal sphincters are presented and summarized. In particular, this paper highlights that the crucial problem in this technology is to maintain long-term biomechanical compatibility between implants and surrounding tissues. Compatibility is affected by changes in both the morphology and mechanical properties of the tissues surrounding the implants. A new approach for enhancing the long-term biomechanical compatibility of implantable artificial sphincters is proposed based on the use of smart materials.

Assessment and in vitro experiment of artificial anal sphincter system based on rebuilding the rectal sensation function

In this paper, a novel artificial anal sphincter (AAS) system based on rebuilding the rectal sensation function is proposed to treat human fecal incontinence. The executive mechanism of the traditional AAS system was redesigned and integrated for a simpler structure and better durability. The novel executive mechanism uses a sandwich structure to simulate the basic function of the natural human anal sphincter. To rebuild the lost rectal sensation function caused by fecal incontinence, we propose a novel method for rebuilding the rectal sensation function based on an Optimal Wavelet Packet Basis (OWPB) using the Davies-Bouldin (DB) index and a support vector machine (SVM). OWPB using a DB index is used for feature vector extraction, while a SVM is adopted for pattern recognition.Furthermore, an in vitro experiment with the AAS system based on rectal sensation function rebuilding was carried out. Experimental results indicate that the novel executive mechanism can simulate the basic function of the natural human anal sphincter, and the proposed method is quite effective for rebuilding rectal sensation in patients.

Infection rates in a large investigational trial of sacral nerve stimulation for fecal incontinence

INTRODUCTION

Treatment options for patients with fecal incontinence (FI) are limited, and surgical treatments can be associated with high rates of infection and other complications. One treatment, sacral nerve stimulation (SNS), is approved for FI in Europe. A large multicenter trial was conducted in North America and Australia to assess the efficacy of SNS in patients with chronic fecal incontinence. The aim of this report was to analyze the infectious complication rates in that trial.

METHODS

Adult patients with a history of chronic fecal incontinence were enrolled into this study. Those patients who fulfilled study inclusion/exclusion criteria and demonstrated greater than two FI episodes per week underwent a 2-week test phase of SNS. Patients who showed a > or = 50% reduction in incontinent episodes and/or days per week underwent chronic stimulator implantation. Adverse events were reported to the sponsor by investigators at each study site and then coded. All events coded as implant site infection were included in this analysis.

RESULTS

One hundred twenty subjects (92% female, 60.5 +/- 12.5 years old) received a chronically implanted InterStim Therapy device (Medtronic, Minneapolis, MN, USA). Patients were followed for an average of 28 months (range 2.2-69.5). Thirteen of the 120 implanted subjects (10.8%) reported infection after the chronic system implant. One infection spontaneously resolved and five were successfully treated with antibiotics. Seven infections (5.8%) required surgical intervention, with infections in six patients requiring full permanent device explantation. The duration of the test stimulation implant procedure was similar between the infected group (74 min) and the non-infected group (74 min). The average duration of the chronic neurostimulator implant procedure was also similar between the infected (39 min) and non-infected group (37 min). Nine infections occurred within a month of chronic system implant and the remaining four infections occurred more than a year from implantation. While the majority (7/9) of the early infections was successfully treated with observation, antibiotics, or system replacement, all four of the late infections resulted in permanent system explantation.

CONCLUSION

SNS for FI resulted in a relatively low infection rate. This finding is especially important because the only other Food and Drug Administration-approved treatment for end-stage FI, the artificial bowel sphincter, reports a much higher rate. Combined with its published high therapeutic success rate, this treatment has a positive risk/benefit profile.

Is the Quality of Life Better in Patients with Colostomy than Patients with Fecal Incontience?

BACKGROUND

A colostomy offers definitive treatment for individuals with fecal incontinence (FI). Patients and physicians remain apprehensive regarding this option because the quality of life (QOL) with a colostomy is presumably worse than living with FI. The aim of this study, therefore, was to compare the QOL of colostomy patients to patients with FI.

METHODS

A cross-sectional postal survey of patients with FI or an end colostomy was undertaken. QOL measures used included the Short Form 36 General Quality of Life Assessment (SF-36) and the Fecal Incontinence Quality of Life score (FIQOL).

RESULTS

The colostomy group included 39 patients and the FI group included 71 patients. The average FI score for FI group was 12 +/- 4.9 (0 = complete continence, 20 = severe incontinence). In the colostomy group the average colostomy function score was 12.9 +/- 3.8 (7 = good function, 35 = poor function). Analysis of the SF-36 revealed higher social function score in the colostomy group compared to the FI group. Analysis of the FIQOL revealed higher scores in the coping, embarrassment, lifestyle scales, and depression scales in the colostomy group compared to the FI group.

CONCLUSION

A colostomy is a viable option for patients who suffer from FI and offers a definitive cure with improved QOL.

Investigation and treatment of faecal incontinence

Faecal incontinence is a debilitating condition affecting people of all ages, and significantly impairs quality of life. Proper clinical assessment followed by conservative medical therapy leads to improvement in more than 50% of cases, including patients with severe symptoms. Patients with advanced incontinence or those resistant to initial treatment should be evaluated by anorectal physiology testing to establish the severity and type of incontinence. Several treatment options with promising results exist. Patients with gross sphincter defects should undergo surgical repair. Those who fail to respond to sphincteroplasty and those with no anatomical defects have the option of either sacral nerve stimulation or other advanced procedures. Stoma formation should be reserved for patients who do not respond to any of the above procedures.

A review of contemporary surgical alternatives to permanent colostomy

OBJECTIVES

To review the options available to patients with faecal incontinence with failed conservative treatment and/or failed anal sphincter repair and assessing the current indications and results of these options.

METHODS

A literature search of MEDLINE, EMBASE and Cochrane databases was performed using the relevant search terms.

RESULTS

Continent options for patients with severe or end stage faecal incontinence include the creation of a form of an anal neosphincter and more recently sacral nerve stimulation. Over half the patients, who are candidates, may benefit from these procedures, although long term results of sacral nerve stimulation are unknown. Dynamic graciloplasty improves the continence in 44-79% of the patients. The complications include frequent reoperations, high incidence of infection and obstructive defaecation. The success rates of artificial bowel sphincter vary between 24% and 79%. Once functional, the artificial bowel sphincter seems to improve the continence in the majority of the patients. Device removal due to infection, obstructive defaecation and pain is a frequent problem. Sacral nerve stimulation is claimed to result in improvement in continence in 35-100% of patients. The main risks in this procedure are infection, electrode displacement and pain.

CONCLUSIONS

All these procedures have high complication rates and have moderate success rates only. A major proportion of patients will need reoperations and hence high motivation is necessary for patients who undergo these procedures. A uniform standard for measurement of success is also necessary so that these procedures can be compared with each other.

Outcome after implantation of a novel prosthetic anal sphincter in humans

Background

A novel prosthetic anal sphincter (PAS) has been developed that aims to occlude by flattening and angulating the bowel, reproducing the action of the puborectalis muscle. The safety of the PAS has been confirmed in biomechanical, in vitro and long-term animal survival studies. The Medical Devices Agency approved implantation in 12 patients.

Methods

The PAS was placed in the pelvis around the anorectal junction via a transabdominal approach in 12 patients with severe faecal incontinence. The device was activated 6 weeks after surgery. Fibreoptic examination of the mucosa below the device was undertaken at various intervals during review.

Results

At a median follow-up of 59 (range 30–72) months nine of the 12 patients had a functioning PAS. There were no device-related infective complications after the initial operation but one patient developed pseudomembranous colitis and had the device removed. The PAS was effective in restoring continence in ten of 11 patients. Median (range) Cleveland Clinic continence scores improved from 16 (7–20) before to 3 (0–7) after surgery. In two patients the PAS was eventually removed owing to infection after revisional surgery. There was no clinical or histological evidence of gastrointestinal mucosal ischaemia.

Conclusion

The PAS was effective in restoring continence. There was no device-related infection after the initial operation, no device erosion and no clinical or histological evidence of gastrointestinal ischaemia.

Faecal incontinence in adults

Faecal incontinence can affect individuals of all ages and in many cases greatly impairs quality of life, but incontinent patients should not accept their debility as either inevitable or untreatable. Education of the general public and of health-care providers alike is important, because most cases are readily treatable. Many cases of mild incontinence respond to simple medical therapy, whereas patients with more advanced incontinence are best cared for after complete physiological assessment. Recent advances in therapy have led to promising results, even for patients with refractory incontinence. Health-care providers must make every effort to communicate fully with incontinent patients and to help restore their self-esteem, eliminate their self-imposed isolation, and allow them to resume an active and productive lifestyle.

Surgical treatment options for fecal incontinence

Although surgical therapy has been shown to be an effective treatment of anal incontinence, few properly controlled randomized studies have confirmed its efficacy or compared it with biofeedback or other less invasive forms of treatment. Overlapping sphincteroplasty, the most common procedure, seems to confer substantial benefits on patients with sphincter disruptions. However, recent data suggest that results following sphincteroplasty deteriorate with time. There is also disagreement about whether pudendal nerve conduction studies can be used to predict outcome after surgical repair. Salvage options for patients with refractory fecal incontinence include passive or electrically stimulated muscle transfer procedures, implantation of an inflatable artificial anal sphincter, and sacral nerve stimulation. Stimulated graciloplasty is the most commonly used muscle transfer procedure; good to excellent results are reported from a small number of high-volume centers, but multicenter trials with less experienced surgeons have shown a high morbidity rate associated with the procedure. The artificial anal sphincter provides good restoration of continence for most patients who retain the device, but a significant explantation rate due to infection or local complications remains problematic. Sacral nerve stimulation has shown promising early results with minimal associated morbidity. There is a critical need for controlled long-term studies that use objective data collection methods, standardized outcome measures, and validated quality-of-life assessment instruments.

Prospective study of artificial anal sphincter and dynamic graciloplasty for severe anal incontinence

BACKGROUND AND AIMS

Dynamic graciloplasty and artificial anal sphincter are two options for refractory incontinence, the efficacy of which was compared in a prospective study.

PATIENTS AND METHODS

Between November 1966 and June 1998, 16 patients were operated on (artificial anal sphincter 8, dynamic graciloplasty 8). Four consecutive operations with each technique were performed by two colorectal surgeons (one initiated the study with the neosphincter and the other with dynamic graciloplasty). Two independent observers assessed postoperative results at 4-month intervals. Patients were followed up to January 2001, with a median (interquartile range) of 44 (13) months and 39 (15) months for the nesophincter and the dynamic graciloplasty, respectively.

RESULTS

Fourteen patients had complications. In the immediate postoperative period; there were eight cases of wound healing-related problems (four in the graciloplasty group). Perineal infection occurred in one patient in the graciloplasty group. At follow-up there were 11 complications (6 in the neosphincter group). Four patients undergoing neosphincter implantation had erosion or pain at the cuff site and had the implant removed (a new device was reimplanted in one). Four patients undergoing dynamic graciloplasty had the stimulator removed. Postoperatively the neosphincter was associated with a significantly lower score on the continence grading scale of the Cleveland Clinic Florida than graciloplasty.

CONCLUSION

The artificial anal sphincter is a more convenient technique than dynamic graciloplasty for institutions treating small number of patients. However, technical failures and complications during follow-up that require reoperation are very high in both types of treatments.

[Surgical treatment of anal incontinence]

Surgery is mandatory for fecal incontinence when medical treatments and reeducation by biofeedback are ineffective. Sphincter disruption is the most frequent cause. Sphincter repair with or without overlapping is indicated in the large majority of cases. Short-term results are good but result is not ever maintained with time. In case of failure, or when the defect concerns more than 180 degrees, it is necessary to use a substitutive technique. Artificial anal sphincter is often first proposed because of its apparent technical simplicity and because it is cheaper than dynamic graciloplasty. Results are excellent. Failures are due to local infection or device disfunction. Dynamic graciloplastie may be proposed in patients with severe perineal lesions, or failure of the other methods. Its results are also excellent, except for the patients having disordered rectal perception. Sacral nerve stimulation is limited to patients with idiopathic or neurologic incontinence. Because definitive implantation is done only following positive preoperative stimulation test, short-term results are very good.

Complications and functional outcome following artificial anal sphincter implantation

BACKGROUND

The postoperative complications and functional outcome following 24 consecutive implantations of an artificial anal sphincter were assessed prospectively.

METHODS

A total of 24 artificial anal sphincters (Acticon Neosphincter) were implanted in 22 patients (mean age 47 years). The mean follow-up period was 28 (range 6-48) months. Results were assessed prospectively by two independent observers at 4-month intervals. The cumulative probability of artificial anal sphincter removal was analysed by the Kaplan-Meier method.

RESULTS

Five patients were free of complications. During the postoperative period, complications occurred in nine patients, two of whom required reoperation. During follow-up, complications developed in ten patients, nine of whom were reoperated. Definitive device explantation was necessary in seven patients. The cumulative probability of device explantation was 44 per cent at 48 months. The 15 patients with functioning implants were followed up for a mean of 26 (range 7-48) months. Continence grading improved from a mean of 18 (range 14-20) in the preoperative period to 4 (range 0-14) after operation (P < 0.001). Resting anal canal pressure in patients with a functioning implant increased from a mean of 35 (range 8-87) mmHg before operation to 54 (range 34-70) mmHg after implantation (P < 0.01).

CONCLUSION

An artificial anal sphincter is a useful alternative for refractory faecal incontinence but the incidence of late postoperative complications is high.

Recent innovations in the management of fecal incontinence

The importance of having a reproducible scoring system to objectively assess the severity of fecal incontinence and its response to treatment is stressed, and a number of methods are described. The approach to conservative treatment and investigation is outlined. Recent advances in the surgical management of fecal incontinence including the electrically stimulated gracilis neosphincter, sacral nerve stimulation, the artificial anal sphincter, internal anal sphincter augmentation, rectal augmentation, and antegrade colonic irrigation are described in detail.