Experience with a new prosthetic anal sphincter in three coloproctological centres

Treatment of fecal incontinence-is there a light in the end of the tunnel?

Fecal incontinence (FI) is a common disease with higher incidence rates in the elderly population. Treatment of affected patients remains challenging and ranges from conservative management to surgical techniques. Despite all efforts patients often undergo several therapeutic measurements to achieve reasonable functional improvements.Although sacral neuromodulation still remains a key therapy with success rates up to 80%, a significant number of patients do not respond sufficiently and require further treatment.Several artificial bowel sphincter devices exist, which can lead to better functional control in selected patients. Notably, complications after these surgeries do occur frequently and the need for implant replacement is still considerable high.A novel anal band, developed by Agency for Medical Innovations (A.M.I., Austria) is currently under evaluation. This device, composed of silicone and polyester, is placed around the anus outside the external sphincter muscle complex aiming to improve stool continence via mechanical pressure. Early results of this new operation are eagerly awaited.

Simulation of artificial anal sphincter motion and interaction with intestinal environment using SOFA

BACKGROUND

Artificial anal sphincter is an implantable medical device for treating fecal incontinence. Reasonable simulation facilitates the advancement of research and reduces experiments on biological tissue. However, the device's clamping motion and sensor interaction with the intestine in the simulation still require further exploration. This article presents a simulation of the artificial anal sphincter's clamping and sensing and its interaction with the intestinal environment using the Simulation Open Framework Architecture (SOFA).

METHODS

Firstly, the proposed simulation algorithm and its principles in SOFA are analyzed. Secondly, the clamping motion and sensor system of the artificial anal sphincter are simulated. Thirdly, a finite element model of intestine is established based on the properties of intestinal soft tissue. Finally, the in vitro experiments are performed.

RESULTS

The simulation results indicate that the sensor system of the artificial anal sphincter has good sensing performance during the clamping motion and fecal accumulation process. Experiments have shown that optimal sensory capabilities can be achieved as the posture of the artificial anal sphincter with a roll angle between 20° and 40°. The comparison demonstrates a mean absolute error of 10%-20% between simulation and in vitro experimental results for sensor forces, which verifies the effectiveness of the simulation.

CONCLUSION

The proposed novel simulation achieves a more comprehensive interaction between the artificial anal sphincter motion and intestinal environment. This study may provide more effective simulation data for guidance in improving the performance of sensor perception of artificial anal sphincter for further research.

Soft robotics in wearable and implantable medical applications: Translational challenges and future outlooks

This work explores the recent research conducted towards the development of novel classes of devices in wearable and implantable medical applications allowed by the introduction of the soft robotics approach. In the medical field, the need for materials with mechanical properties similar to biological tissues is one of the first considerations that arises to improve comfort and safety in the physical interaction with the human body. Thus, soft robotic devices are expected to be able of accomplishing tasks no traditional rigid systems can do. In this paper, we describe future perspectives and possible routes to address scientific and clinical issues still hampering the accomplishment of ideal solutions in clinical practice.

A Novel Sensor System for In Vivo Perception Reconstruction Based on Long Short-Term Memory Networks

Monitoring bodily pressure could provide valuable medical information for both doctors and patients. Long-term implantation of in vivo sensors is highly desirable in situations where perception reconstruction is needed. In particular, for fecal incontinence, artificial anal sphincters without perceptions could not remind patients when to defecate and even cause ischemic tissue necrosis due to uncontrolled clamping pressure. To address these issues, a novel self-packaging strain gauge sensor system is designed for in vivo perception reconstruction. In addition, long short-term memory (LSTM) networks, which show excellent performance in processing time series-related features and fitting properties, are used in this article to improve the prediction accuracy of the perception model. The proposed system has been tested and compared with the traditional linear regression (LR) approach using data from in vitro experiments. The results show that the Root-Mean-Square Error (RMSE) is reduced by more than 69%, which demonstrates that the prediction accuracy of the proposed LSTM model is higher than that of the LR model to reach a more accurate prediction of the amount of intestinal content. Furthermore, outcomes of in vivo experiments show that the robustness of the novel sensor system based on long short-term memory networks is verified through experiments with limited data.

ACG Clinical Guidelines: Management of Benign Anorectal Disorders

Benign anorectal disorders of structure and function are common in clinical practice. These guidelines summarize the preferred approach to the evaluation and management of defecation disorders, proctalgia syndromes, hemorrhoids, anal fissures, and fecal incontinence in adults and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence for these guidelines was assessed using the Grading of Recommendations Assessment, Development and Evaluation process. When the evidence was not appropriate for Grading of Recommendations Assessment, Development and Evaluation, we used expert consensus to develop key concept statements. These guidelines should be considered as preferred but are not the only approaches to these conditions.

[Anal incontinence]

Anal incontinence describes the uncontrolled transanal passage of gaseous, solid or liquid intestinal contents. It can be a considerable psychosocial burden and impairment of the quality of life for those affected. The cause can be primary damage to the continence organ or incontinence can be a secondary symptom of other diseases. The detailed patient history and clinical examination document the severity of incontinence, impairment of quality of life and pathomorphological changes. The treatment is primarily conservative. A combination of conservative therapeutic approaches can often achieve satisfactory symptom relief. If conservative treatment remains insufficient, surgical measures can be considered. Sphincteroplasty and sacral neuromodulation are the preferred surgical interventions.

An artificial anal sphincter based on a novel clamping mechanism: Design, analysis, and testing

An artificial anal sphincter is a device to help patients with fecal incontinence rebuild the ability to control the excrement through the anus. In this article, an artificial anal sphincter based on a novel clamping mechanism (AASNCM) is proposed to improve the safety and reliability. The AASNCM, which is powered by a transcutaneous energy transfer system, consists of a novel clamping mechanism, a receiving coil and a control unit. According to design requirements, the novel clamping mechanism model was established. After that, its kinematics and dynamics were analyzed. The results of force tests on the prototype AASNCM show that the maximum values of clamping force and expanding force are 15.859 and 31.029 N, respectively. Comparing the experimental results with theoretical analysis, a good match can be concluded. Finally, in vitro experiments were conducted, and have verified the safety and reliability of the proposed AASNCM.

What Is Fecal Incontinence That Urologists Need to Know?

Fecal incontinence (FI) undoubtedly reduces quality of life and adversely affects the social life of the affected individual. FI has a higher prevalence with age and has an equivalent prevalence to urinary incontinence in patients with genitourinary disease, but is often not confirmed in these cases. A thorough investigation is needed to diagnose FI, with the common etiology of this condition in mind, and several questionnaires can be used to identify symptoms. The physical examination contains digital rectal examination carries out to identify the patient's condition. Ultrasound, colonoscopy, and rectum pressure test can be performed. Patients educated in diet-related issues, bowel movements, and defecation mechanism. Nonoperative options such as diet control and Kegel exercise should be performed at first. Surgical treatment of FI is considered when conservative management and oral medications produce no improvement. Surgical options include less invasive procedures like bulking agent injections, and more involved approaches from sacral nerve stimulation to invasive direct sphincter repair and artificial bowel sphincter insertion. Good outcomes in FI cases have also recently been reported for barrier devices.

Short-, long-, and very long-term results of secondary anterior sphincteroplasty in 20 patients with obstetric injury

PURPOSE

More long-term follow-up studies beyond 10 years after secondary sphincteroplasty for obstetric damage are warranted. This prospective study aimed to compare reported data on incontinence and satisfaction in a cohort of such patients examined at short-, long-, and very long-term follow-up.

METHODS

Twenty out of 33 obstetric patients (61%) operated with secondary anterior overlapping sphincteroplasty during February 1996 to April 2004 were evaluated preoperatively and at short-, long-, and very long-term follow-up. Anal incontinence was scored by a combination of Wexner's and St. Mark's incontinence scores. The patients also reported degree of treatment satisfaction.

RESULTS

Twenty patients were examined preoperatively and after a median (range) of 5 (2-62), 102 (64-162), and 220 (183-278) months. Corresponding incontinence scores were 11.5 (5-18), 5.5 (1-17) (p < 0.01), 10.0 (0-18) (p > 0.05), and 12.0. (1-18) (p > 0.05). With increasing follow-up times, patients reporting a better outcome were 75%, 65%, and 45%. At very long-term follow-up patients, reports were more dismal than expected in those also reporting improved incontinence cores. Incontinence scores did not improve in patients with neuropathy (n = 5) or patients (n = 5) with more than 10 years of symptoms.

CONCLUSION

Initial improvement of anal incontinence attenuated with time, in particular from short- to long-term follow-up. Patients with neuropathy experienced no improvement of incontinence. Beyond stoma formation, in compliant patients, one should consider other treatment options like sacral nerve stimulation and neosphincter formation.

Design and evaluation of puborectalis-like artificial anal sphincter that replicates rectal perception

While fecal incontinence (FI) is not fatal, it can dramatically decrease the patient's quality of life. An artificial anal sphincter (AAS) is an implantable device that treats FI by replacing a diseased or damaged anal sphincter, thus allowing the patient's continence to be maintained. Here, we report a novel implantable puborectalis-like artificial anal sphincter (PAAS) that replicates rectal perception and has a low risk of ischemia necrosis. Using the pressure sensors embedded in the PAAS, the relationship between the mass of feces and the pressure was determined, and a feces mass estimation model was developed based on in vitro studies. Rectal perception is provided through the real-time monitoring of rectal feces, and the feeling of defecation is quantified based on a comparison between the feces mass and a preset threshold mass. In vivo studies were performed for validation, and the accuracy of the model was determined to be as high as 90%. The performance of the PAAS in the real-time monitoring of rectal feces and its in vivo biocompatibility were also evaluated. The device should further the functionality of existing AAS systems while improving their biosafety and thus expand the applicability of implantable AAS systems in the treatment of FI.

Artificial Muscle Devices: Innovations and Prospects for Fecal Incontinence Treatment

Fecal incontinence describes the involuntary loss of bowel content, which is responsible for stigmatization and social exclusion. It affects about 45% of retirement home residents and overall more than 12% of the adult population. Severe fecal incontinence can be treated by the implantation of an artificial sphincter. Currently available implants, however, are not part of everyday surgery due to long-term re-operation rates of 95% and definitive explantation rates of 40%. Such figures suggest that the implants fail to reproduce the capabilities of the natural sphincter. This article reviews the artificial sphincters on the market and under development, presents their physical principles of operation and critically analyzes their performance. We highlight the geometrical and mechanical parameters crucial for the design of an artificial fecal sphincter and propose more advanced mechanisms of action for a biomimetic device with sensory feedback. Dielectric electro-active polymer actuators are especially attractive because of their versatility, response time, reaction forces, and energy consumption. The availability of such technology will enable fast pressure adaption comparable to the natural feedback mechanism, so that tissue atrophy and erosion can be avoided while maintaining continence during daily activities.

Power flow control of TET system for a novel artificial anal sphincter system

This paper presents an adaptive transcutaneous energy transfer system (TETS) integrated with a novel elastic scaling artificial anal sphincter system (ES-AASS) for treating severe faecal incontinence (FI). The ES-AASS is based on a novel executive mechanism that uses a spring scalable structure to clamp the rectum. To deliver the correct amount of power (i.e. to match the load demand under variable coupling conditions or different operation stages of the implanted device) for internal battery charging and ensure safety for the human body, theoretical analysis was conducted as a control rule with respect to the relationship between the phase of driver signals and output voltage. An easy regulating procedure to stabilize output voltage with a phase shift controller is also presented. To validate the phase control rules, a prototype of the TETS was constructed and its performance was validated across the whole coupling coefficient range (0.09 ∼ 0.29) as well as load resistance (50 ∼ 120 Ω). The results show that the output voltage of the secondary side can be maintained at a constant 7 V with a phase regulation range of 78.7-178.2° and the proposed controller has reached a maximal end-to-end power efficiency of 74.2% at 1 W.