["Flowsecure" artificial urinary sphincter: a new adjustable artificial urinary sphincter concept with conditional occlusion for stress urinary incontinence]

Urethral pressure profile assessment after artificial urinary sphincter implantation (FlowSecure™ and AMS-800™): A case series

The AMS-800^™ artificial urinary sphincter has become the 'gold standard' in the treatment of male stress urinary incontinence. In 2006, the novel artificial urinary sphincter FlowSecure^™ containing a stress relief balloon providing low cuff pressures at rest with conditional pressure elevation during periods of stress has been launched. We assessed the intraurethral pressure in the cuff area of the AMS-800 and the FlowSecure by urethral pressure profile in four patients each. Urethral pressure profile was performed at rest and during coughing. In addition, continence situation and patient satisfaction after artificial urinary sphincter implantation was assessed. At rest, median pressure in the cuff region was 74 (38-117, FlowSecure) cm H₂O and 102 (95-110, AMS-800) cm H₂O. During coughing, pressure peaks rose to 135 (54-162, FlowSecure) cm H₂O and 202 (128-216, AMS-800) cm H₂O. Median pad usage before artificial urinary sphincter implantation in the FlowSecure and the AMS-800 group was 4 (3-4) and 4.5 (2-6) pads/24 h, respectively. At the time of urodynamic investigation, median pad usage declined to 1.5 (0-4) pads/24 h in the FlowSecure and to 1 (1-2) pads/24 h in the AMS-800 group. Seven of eight patients reported on a satisfactory quality of life, and one patient remained unhappy after FlowSecure implantation. It remains unclear if the trade-off in favour of lower cuff pressures, and consecutively lower intraurethral pressures, holds truly long-term benefits regarding device revision, explantation and patient satisfaction.

A PASSIVE STATE SIMULATION OF AN ANAL SPHINCTER USING SIMMECHANICS

Nowadays, different mechanical artificial sphincters can be found implanted in human beings, trying to overcome a deficiency in the performance of the natural one. However, they do not take into account the natural anal sphincter’s (AS) dimensions, and autonomous response; they also lack in basic contraction and relaxation properties. In this paper, by addressing the AS behavior, an AS model designed with Matlab/SimMechanics is shown. The model comprises bodies of concentrated mass interconnected by springs. The mass–spring system is arranged in concentric rings where every concentrated mass is interconnected by a spring. Each spring takes specific stiffness, which varies with length, in accordance to an experimental curve. The system described can be loaded or unloaded, describing then the muscle behavior.

Each element that forms the model of rings is subject to displacements caused by forces of traction and compression, when a radial force is applied from the center towards the inner ring. The springs of the inner ring experience forces of traction, whereas the springs that connect the body of the inner ring with the outer ring perpendicularly are submitted to compression forces.The data used in the proposed model corresponded to dimensions of the humanAS: width, height, rigidity, stress, tension, basically obtaining an initial deformation behavior according to the sphincter in the passive state. The model remained stable with some mechanical oscillations due to the elastic elements; by modifying one of the parameters, the behavior became unstable and unmanageable. It was verified that it is a sensitive model when modifying the initial conditions that the concrete data requires in case of reproducing the sphincter muscle with particular dimensions.

Surgery for stress urinary incontinence due to presumed sphincter deficiency after prostate surgery

BACKGROUND

Incontinence after prostatectomy for benign or malignant disease is a well-known and often a feared outcome. Although small degrees of incidental incontinence may go virtually unnoticed, larger degrees of incontinence can have a major impact on a man's quality of life.Conceptually, post-prostatectomy incontinence may be caused by sphincter malfunction or bladder dysfunction, or both. Most men with post-prostatectomy incontinence (60% to 100%) have stress urinary incontinence, which is involuntary urinary leakage on effort or exertion, or on sneezing or coughing. This may be due to intrinsic sphincter deficiency and may be treated with surgery for optimal management of incontinence. Detrusor dysfunction is more common after surgery for benign prostatic disease.

OBJECTIVES

To determine the effects of surgical treatment for urinary incontinence related to presumed sphincter deficiency after prostate surgery for:- men with lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH) - transurethral resection of prostate (TURP), photo vaporisation of the prostate, laser enucleation of the prostate or open prostatectomy - and- men with prostate cancer - radical prostatectomy (retropubic, perineal, laparoscopic, or robotic).

SEARCH METHODS

We searched the Cochrane Incontinence Group Specialised Register, which contains trials identified from Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE in process, ClinicalTrials.gov, and handsearching of journals and conference proceedings (searched 31 March 2014); MEDLINE (January 1966 to April 2014); EMBASE (January 1988 to April 2014); and LILACS (January 1982 to April 2014). We handsearched the reference lists of relevant articles and conference proceedings. We contacted investigators to locate studies.

SELECTION CRITERIA

Randomised or quasi-randomised trials that include surgical treatments of urinary incontinence after prostate surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the trials identified, appraised quality of papers, and extracted data.

MAIN RESULTS

Only one study with 45 participants met the inclusion criteria. Men were divided in two sub-groups (minimal or total incontinence) and each group was randomised to artificial urethral sphincter (AUS) implantation or Macroplastique injection. Follow-up ranged from six to 120 months. In the trial as a whole, the men treated with AUS were more likely to be dry (18/20, 82%) than those who had the injectable treatment (11/23, 46%) (odds ratio (OR) 5.67, 95% confidence interval (CI) 1.28 to 25.10). However, this effect was only statistically significant for the men with more severe ('total') incontinence (OR 8.89, 95% CI 1.40 to 56.57) and the CIs were wide. There were more severe complications in the group undergoing AUS, and the costs were higher. AUS implantation was complicated in 5/22 (23%) men: the implant had to be removed from one man because of infection and in one man due to the erosion of the cuff, in one man the pump was changed due to mechanical failure, in one man there was migration to the intraperitoneal region, and one man experienced scrotal erosion. In the injectable group, 3/23 (13%) men had a complication: one man treated with Macroplastique injection had to be catheterised because of urinary retention and two men developed urinary tract infections.

AUTHORS' CONCLUSIONS

The evidence available at present was of very low quality because we identified only one small randomised clinical trial. Although the result was favourable for the implantation of AUS in the group with severe incontinence, this result should be considered with caution due to the small sample size and uncertain methodological quality of the study found.

Management of male urinary incontinence

The majority of male urinary incontinence seen is secondary to sphincter weakness following prostatic surgery. As there is a rising elderly population and increasing numbers of surgical interventions for prostate cancer, incidence of male incontinence is increasing. Hence, management of male incontinence has become a subject of increased interest for urologists. Various non-surgical and surgical approaches have been suggested for this devastating condition. Non-invasive therapies are suggested for early postoperative and mild incontinence. For surgical treatment the artificial urinary sphincter is still labeled the gold standard despite the introduction of several more minimally invasive treatments. However, as yet there is no consensus on the optimal timing and best modality for managing these men. Well designed, centrally funded clinical trials are required to establish which treatment modality to offer and when in the broad spectrum of male incontinence. This review focuses mainly on the management of post-prostatectomy incontinence since the management of other types varies little from the modalities of treatment in women.

[Follow-up of the FlowSecure artificial urinary sphincter]

The AMS-800 artificial urinary sphincter has been the only prosthesis available for treatment of stress urinary incontinence refractory to other therapeutic modalities for the past 25 years. The relatively high rate of complications occurring with the AMS-800 device during this time led to introduce a number of changes in its design that resulted in a new prostheses, the FlowSecure artificial sphincter. The FlowSecure artificial urinary sphincter is an adjustable prosthesis filled with normal saline without contrast. Plain X-rays cannot therefore be used for monitoring, and ultrasound is the most adequate radiographic technique for evaluation. In addition to calculating the post-void residue, ultrasound allows for verifying prosthesis status and for calculating the urethral occluding pressure. A detailed clinical history and flow rate measurement should be used together with the ultrasound scan to functionally assess patients with the FlowSecure device in order to determine the need for adjusting system pressure to the minimum pressure required for total continence.