Development and Current Status of the AMS 800 Artificial Urinary Sphincter

Development and future prospects of the artificial urinary sphincter

BACKGROUND

Urinary incontinence is a urinary disorder in which urine leaks out involuntarily. This disorder seriously affects the quality of life of patients. For patients with mild incontinence, conservative treatment and medication may be the ideal treatment modality, but for patients with severe incontinence, an artificial urinary sphincter is currently a better treatment option.

METHODS

In order to design an ideal artificial urinary sphincter, this article first searched and collected literature based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses searched strategy by selecting specific subject terms and reviewed the artificial urinary sphincters that are currently in the research stage based on different activation methods.

RESULTS

In response to the deficiencies of the existing artificial urinary sphincter, this article discusses the future optimization of the artificial urinary sphincter from three aspects: individual improvement of the artificial urinary sphincter, engineering design elements, and optimization of the artificial urinary sphincter manufacturing process.

CONCLUSIONS

The manufacture of an idealized artificial urinary sphincter capable of meeting clinical needs is of great importance to improve the quality of life of patients. However, this approach is a reasonable option to explore and should not be overestimated until further evidence is available.

A magnetic endourethral sphincter against stress urinary incontinence: preliminary pilot study in humans

BACKGROUND

Urinary incontinence (UI) is a common and frustrating condition that affects patients' quality of life as well as the Healthcare systems. Currently, the most severe cases of UI are treated using implanted, invasive artificial sphincters. We propose an innovative, minimally invasive magnetic endourethral sphincter for the treatment of stress UI (SUI) in patients for whom previous medical and surgical treatments have failed.

METHODS

Six patients with severe SUI were enrolled at a single center and underwent cystoscopic sphincter implantation. After 10 days, correct device position was confirmed by ultrasonography. The sphincter was explanted after 28 days.

RESULTS

In all patients, the sphincter was successfully implanted using an endoscopic approach. One patient reached the end of the pilot test (28 days) with the sphincter correctly placed. Patients' responses on the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form questionnaire improved from a score of 18 out of 21 at the screening visit (UI without reasons) to a score of 3 out of 21 (almost perfect continence). No major pain and discomfort were reported.

CONCLUSIONS

This study showed the feasibility of sphincter implantation, explantation, and overall tolerability, although a redesign of the sphincter distal part is needed.

Severe Complications of Artificial Urinary Sphincter Placement in a Young Woman With Neurogenic Urinary Incontinence: A Case Report

This article reports a case of a 40-year-old woman with a history of myelomeningocele and neurogenic urinary incontinence who developed erosion and fistula formation following the placement of an artificial urinary sphincter (AUS) when she was 18 years old. The patient had a long-standing history of urinary incontinence that was unresponsive to prior surgeries for meningomyelocele. She reported the loss of uro-fecal material from the vagina but did not seek further medical evaluation until the age of 40. Clinical examination revealed protruding tubes from the suprapubic region. The administration of a contrast agent through one of the two tubes led to the visualization of intestinal loops, and the administration of a contrast agent through the urethra confirmed the connection between the rectum, urinary bladder, and vagina. Due to the absence of reliable surgical history and in the absence of abdominal discomfort, bilateral nephrostomies were initially performed to prevent further uro-fecal material loss. The patient showed significant improvement, decided to not seek further evaluation and surgical treatment, and remained socially integrated during the follow-up period of 20 years. This case highlights the severe consequences of AUS placement in a young woman with neurogenic urinary incontinence and emphasizes the importance of proper patient selection and management in the presence of underlying neurological disorders.

A systematic review and meta-analysis of complications of artificial urinary sphincters in female patients with urinary incontinence due to internal sphincter insufficiency

BACKGROUND

Urinary incontinence (UI) is a common worldwide rising health issue among women with a prevalence of 5 to 70%. Stress urinary incontinence (SUI) is the most common subtype of UI. There are different treatments for UI, including AUS (artificial urinary sphincter) implantation, as one of the surgical options for treating SUI. The aim of this study was to determine the complication rate of AUS, exclusively in female patients with SUI, which resulted from ISD (intrinsic sphincter deficiency). We also compared the complication rate between minimally invasive (laparoscopic or robotic surgery) and open approaches.

METHODS

Scopus, PubMed, Web of Science, Embase, and Google Scholar were searched for studies regarding complications in AUS implantation surgery, from the beginning of the project to March 2022. After screening and reviewing of full text, the general characteristics of the study and study population including follow-up time, type of surgery, and the number of complications that occurred such as necrosis, atrophy, erosion, infection, mechanical failure, revision, and leak, were extracted.

RESULTS

We found that atrophy occurred in 1 of 188 (0.53%) patients treated with minimally invasive surgery and in 1 of 669 (0.15%) patients treated with open surgery. None of the 17 included studies reported the occurrence of necrosis in the patients under study. Erosion occurred in 9 of 188 (4.78%) patients treated with minimally invasive surgery and in 41 of 669 (6.12%) patients treated with open surgery. Infection occurred in 12 of 188 (6.38%) patients treated with minimally invasive surgery and in 22 of 669 (3.2%) patients treated with open surgery. The mechanical failure occurred in 1 of 188 (0.53%) patients treated with minimally invasive surgery and in 55 of 669 (8.22%) patients treated with open surgery. Reconstructive surgery occurred in 7 of 188 (3.72%) patients treated with minimally invasive surgery and in 95 of 669 (14.2%) patients treated with open surgery. Leaks occurred in 4 of 188 (2.12%) patients treated with minimally invasive surgery and in 6 of 669 (0.89%) patients treated with open surgery. The type of surgery was associated with a statistically significant increase in mechanical failure (p-value = 0.067) and infection (p-value = 0.021), and reconstructive surgery (p-value = 0.049). Out of the 857 participats in the study,469 were studied for less than five years and 388 were studied for more than five years.21 of 469 (4.4%) (p-value = 0.08) patients and 81 of 388 (20.8%) (p-value = 0.001) patients required reconstructive surgery. Erosion occurred in 23 of 469 (4.9%) (p-value = 0.01)patients with following time less than five years and in 27 of 388 (6.9%) (p-value = 0.001) patients with following time more than five years.

CONCLUSION

The use of artificial urinary sphincters in the treatment of UI causes complications such as atrophy, erosion, and infection; the amount of which is influenced by the surgical method and the duration of using the artificial urinary sphincter. It seems that the use of new surgical methods, such as laparoscopic surgery, is useful in reducing the incidence of complications.

Artificial Urinary Sphincter With Bilateral Atrophic Kidneys and Accessory Renal Arteries in a Male Cadaveric Subject: A Case Report and Clinicopathological Reconciliation of Urinary Abnormalities and Embryogenetic Correlation of Vascular Aberrations

A unique combination of triple abnormality in a willed male body donor dissection, with putative clinicopathological correlations during the subject's lifetime, is described in this case report. The subject had a three-piece artificial urinary sphincter surgically implanted around the proximal corpus spongiosum, left scrotal pouch and in the lower left abdominal wall, ostensibly for urinary incontinence during his lifetime, though the etiology of the latter was not immediately obvious. He also had a total of three accessory renal arteries involving both sides, complicated by bilateral diffuse renal atrophy from presumable glomerulosclerosis or nephrosclerosis-induced nephrotic syndrome. While each entity may not be so unique per se, each is not too common either. The combination of all three findings has not been described to date in the contemporary literature in a single male cadaver dissection. Only seven reports of artificial urinary sphincter studies on human cadaver subjects could be detected in contemporary literature, this being the eighth. Finally, there were no apparent etiopathological or pathogenetic mechanisms to explain the occurrence of each or the coexistence of all of them in a single male cadaveric subject. The artificial urinary sphincter was reviewed with respect to its characteristics, placement, and efficacy. An attempt was made to establish the cause-effect relationship between the artificial sphincter and urinary incontinence that necessitated the implant. Thereafter, a clinicopathological correlation was proposed in this case report to reconcile the concomitance of urinary incontinence, bilateral accessory renal arteries, and bilateral renal atrophy. An embryogenetic mechanism of the aberrant renal arteries was also suggested. Physician awareness from the standpoint of preoperative investigation of such cases was also highlighted.

The role of transcorporal cuff placement in high-risk and ultra-high-risk patients: are they actually helpful?

PURPOSE

To assess the incidence of artificial urinary sphincter (AUS) explant in high-risk patients and to evaluate the relationship between transcorporal cuff (TCC) placement and explant risk in this population.

METHODS

We retrospectively reviewed all AUS insertions performed on high-risk patients by a single surgeon from 2010 to 2020. "High-risk" was defined as having ≥ 1 urethral risk factor: pelvic radiation, urethroplasty, recalcitrant urethral/bladder neck stenosis, urethral stenting, or previous AUS erosion/infection. Patients with ≥ 2 factors were "ultra-high-risk." Time-to-event analyses were used to assess all-cause-, infection/erosion-related-, and mechanical failure-related explant-free survival. Subgroup analyses were performed for patients with a history of radiation and urethral dissection.

RESULTS

The final cohort included 68 men, mean age of 67 years (SD 11), and 77 AUS cuffs. Mean follow-up was 32 months (IQR 6-50). 29% of cuffs (n = 22) were transcorporal. 32 cuffs (42%) were explanted. All-cause explant-free survival was 64% at 1 year and 52% at 2 years. Classification as "ultra-high-risk" was not associated with explant risk (all p-values > 0.05). TCC placement was associated with an increased risk of explant for infection/erosion across all patients (HR 2.74, p = 0.03) and in radiated patients (n = 50; HR 4.1, p = 0.04), but not in patients with prior urethral dissection (n = 52; HR 1.98, p = 0.21).

CONCLUSION

High-risk patients have a high rate of AUS explant and TCC placement may not be protective in this population. TCC placement was associated with an increased risk of infection/erosion in radiated patients, but not in those with a history of open urethral surgery.

Multicentered Assessment of Clinical Outcomes and Factors Associated With Failure of the Adjustable TransObturator Male System (ATOMS)

OBJECTIVE

To assess postoperative outcomes from the Adjustable TransObturator Male System (ATOMS) and identify factors influencing failure to achieve continence.

PATIENTS AND METHODS

A multicentered analysis was performed on all patients treated for postprostatectomy incontinence using the third-generation ATOMS at 9 Canadian tertiary referral centers. The primary outcome was continence (defined as requiring ≤1 pad postoperatively for patients requiring ≥2 pads preoperatively and 0 pads for those requiring 1 pad preoperatively). Secondary outcomes included improvement (>50% change in pad use), patient satisfaction, explantation, and postoperative complications.

RESULTS

Two hundred and eighty nine patients with a mean age of 68.9 years were analyzed. Pre-operatively mean pad per day use was 4.2 (1-12), 31.5% of patients reported severe incontinence (≥5 pads/day), 33.9% had concurrent radiotherapy and 19.4% had failed previous incontinence surgery. Overall continence rate was 73.3% (n = 212) at a mean follow-up of 19.6 months. More than eighty nine percent (89.3%) (n = 258) of patients experienced >50% improvement, 84.4% (n = 244) of patients were satisfied with the results of surgery. More than seven percent (7.9%) (n = 23) required device explantation. On multivariate Cox regression analysis, concurrent radiotherapy (hazard ratio [H.R.] 2.3, P < .001), diabetes (H.R. 2.2, P = .007) and increased pre-operative pad usage (H.R. 1.1, P = .02) were each associated with failure to achieve continence, while patient age (P = .60), obesity (P = .08), prior urethral stenosis (P = .56), and prior incontinence surgery (P = .13) were not. Radiation therapy was also associated with device explantation (H.R. 2.7, P = .02).

CONCLUSION

ATOMS is a safe and efficacious for treatment of postprostatectomy incontinence. However, patients with prior radiation, increased pre-operative pad use, or diabetes are less likely to achieve continence.

The History of Nontraditional or Ectopic Placement of Reservoirs in Prosthetic Urology

INTRODUCTION

Reservoir placement during implantation of prosthetic urology devices has been problematic throughout the history of the surgical treatment of erectile dysfunction and urinary incontinence. We thought it would be interesting to review the history of reservoir placement leading up to current surgical techniques.

AIM

To provide an overview of the past and present techniques for reservoir placement and discuss the evolutionary process leading to safe and effective placement of prosthetic reservoirs.

METHODS

We reviewed data pertaining to inflatable penile prosthesis (IPP) reservoirs and pressure-regulating balloons (PRB) in a chronological fashion, spanning 25 years.

MAIN OUTCOME MEASURES

Main outcomes included a historical review of techniques for IPP reservoir and PRB placement leading to the subsequent incremental improvements in safety and efficacy when performing penile implants and artificial urinary sphincters.

RESULTS

Prosthetic urologic reservoirs have traditionally been placed in the retropubic space. Over the years, urologists have attempted use of alternative spaces including peritoneal, epigastric, "ectopic," posterior to transversalis, and high submuscular.

CONCLUSION

Current advances in prosthetic urologic reservoir placement allow safe and effective abdominal wall placement of reservoirs. These novel approaches appear to be so effective that urologists may now be able to cease using the traditional retropubic space for reservoir placement, even in the case of virgin pelves.

Urethral lumen occlusion by artificial sphincteric device: Evaluation of degraded tissues effects

Urinary incontinence can be surgically treated by means of artificial sphincters, based on a cuff that provides a pressure around the urethra to occlude the lumen. Considering the frequent access of elderly patients to this surgical practice, tissue degradation phenomena must be investigated, since they could affect treatment reliability and durability. The potential degradation can be interpreted considering a variation within soft tissue constitutive formulation, by means of a correlation between mechanical properties and tissues ageing. The overall compressibility varies, as characteristics aspect of soft tissue mechanical response with age, as well as the stiffness. The investigation is performed by means of a three dimensional numerical model of the urethral duct. The effects of the interaction phenomenon with a cuff is interpreted considering the changes, within the constitutive models, of the basic parameters that define the potential degradation process. The deformation related to compressibility is recalled, ranging between ten and fifty percent in dependence on the degradation level considered. This parameter, reported mostly as representative of the aging effect, shows a large variation that confirms the relevance of the investigation performed toward a sensitivity of the mechanical response of the urethral duct referred to the lumen occlusion.

Implantable Systems for Stress Urinary Incontinence

Stress urinary incontinence (SUI), the involuntary urine leakage due to failure of the urethral closure mechanism, is a global health challenge with substantial human suffering and socioeconomic costs. Approximately 167 million male and female patients are predicted to suffer from SUI in 2018, worldwide. A wide range of surgical interventions are available for the treatment of SUI. Severe cases, however, usually require the implantation of artificial urinary sphincter devices. This review comparatively presents and analyzes the working principles, as well as the challenges, associated with the current implantable SUI systems in clinical use. These include slings, urethral bulking agents, artificial urinary sphincters, and adjustable continence devices. It further reports on recent research progress and state-of-the-art in the field of SUI implants, including an original approach proposed by the authors with a pressure feedback sensory mechanism. The new emerging field of artificial muscle devices, including electroactive polymers, provides a promising innovative solution for replacing the weakened urethral sphincter in SUI patients.

Genitourinary Prosthetics: A Primer for the Non-urologic Surgeon

Genitourinary prosthetics are used for correction of functional deficits and to improve the quality of lives of affected patients. General surgeons must evaluate patients scheduled for nonurologic surgery with urologic devices that can impact their perioperative management. Lack of recognition of these prosthetics preoperatively can lead to unnecessary morbidity for the patient and have legal implications for the surgeon. Close consultation with a urologist may avoid common complications associated with these devices and allows for surgical assistance when operative misadventures do occur. This article reviews 3 common urologic prosthetics: testicular prosthesis, artificial urinary sphincter, and penile prosthesis.

Evaluation of percutaneously adjustable hydraulic urethral sphincters with and without induced mechanical failure

OBJECTIVE

To describe (1) the radiographic appearance of intact hydraulic urethral sphincters (HUS) and (2) the success of leak detection using clinically feasible methods.

STUDY DESIGN

Prospective, blinded in vitro study.

SAMPLE POPULATION

Thirty HUS devices (10 each of 8, 10, and 12 mm diameter sizes).

MATERIALS AND METHODS

All devices were inflated with saline (0.9% NaCl) solution to complete occlusion, inspected, and weighed over a 24-hour period for manufacturing defects. HUS phantoms were created to mimic surrounding soft tissues. One randomly selected HUS of each size was evaluated radiographically at different inflation volumes and angles. All HUS systems were then evaluated in random order before and after puncture with volumetry, manometry, radiography, and contrast fluoroscopy. Volumetry was the total volume (mL) retrieved from each HUS system. Manometry was the pressure (cm H2 O) within each HUS system. The HUS devices were filled to a known volume before each measurement.

RESULTS

When all HUS sizes were considered, volumetry did not reveal significant differences before and after puncture, but manometry was significantly different (P < .001). Radiography was 63.8% sensitive and 88.3% specific for puncture diagnosis, with inter-observer agreement of 0.58. Contrast fluoroscopy was 78.4% sensitive and 100% specific, with inter-observer agreement of 0.97.

CONCLUSIONS

Of those methods tested, contrast fluoroscopy was the most sensitive, specific, and consistent method of leak detection. Manometry was also helpful, but may be difficult to use clinically. Volumetry and radiography were relatively poor indicators of leakage in this model.

The current role of the artificial urinary sphincter in male and female urinary incontinence

The evolution of the artificial urinary sphincter has affected the current surgical options for urinary incontinence. With its unique features, the artificial urinary sphincter (AUS) has been an attractive option for the treatment of urinary incontinence regardless of gender. The current paper discusses the indications, contraindications, types of devices, surgical approaches, outcomes, and complications of the AUS in the treatment of both male and female urinary incontinence. A PubMed review of the available literature was performed and articles reporting implantation of artificial urinary sphincters for urinary incontinence in both male and female patients were evaluated. There was a comparable satisfactory continence rate after the implantation of an AUS (59~97% in males vs. 60~92% in females). In comparison, there were some differences in the indications, contraindications, surgical approaches, outcomes, and complications of the AUS implanted for urinary incontinence in male and female patients. AUS implantation is a safe and effective surgical option for the treatment of urinary incontinence of various etiologies. Continuous evolution of the device has made it an attractive option for the treatment of both male and female urinary incontinence.

[Dysfunctions of artificial urinary sphincters (AMS 800) and their management via a transscrotal access. Optimum procedure illustrated by reference to clinical examples]

BACKGROUND

The introduction of a transscrotal access for implantation of an artificial urinary sphincter (AUS) offers an alternative to the perineal approach for dealing with post-prostatectomy incontinence. Should a revision be necessary, the entire implant can be explored via this access and only one incision is needed. The aim of our study was to present the advantage of the transscrotal approach in different malfunctions of AUSs (AMS 800).

MATERIALS AND METHODS

Surgical exploration was exemplary indicated in three male patients because of recurrent incontinence after artificial sphincter implantation. The reasons for malfunction were urethral atrophy, a mechanical defect of the device, and urethral erosion of the cuff, which led to explantation via the perineal approach of the entire artificial sphincter system. The patient whose sphincter system had a mechanical defect had the entire system substituted by the transscrotal route. In the case of perineal explantation a complete new AMS 800 system was implanted transscrotally at the unaffected bulbar ureter following complete healing. In the case of urethral atrophy a tandem-cuff was implanted by a transscrotal approach. Because of mechanical complications the whole system was exchanged, a completely new AUS (AMS 800) system being implanted by the transscrotal approach after perineal explantation.

RESULTS

There were no complications of any of the revision operations. The postoperative course was uneventful and after activation of the system all patients regained their former continence status. Three months after implantation all patients remained continent and their AMS 800 sphincter systems were fully functional.

CONCLUSION

When a revision operation is needed, the transscrotal access offers a quick and easy alternative to the perineal method. Our patients had no postoperative complications, and their continence rates were satisfactory. Further studies are needed to reveal whether this approach will prove superior to the perineal approach in the long term.