Memokath® stents for the treatment of detrusor sphincter dyssynergia (DSD) in men with spinal cord injury: The Princess Royal Spinal Injuries Unit 10-year experience

Detrusor Sphincter Dyssynergia

Detrusor sphincter dyssynergia (DSD) is defined as a detrusor contraction concurrent with an involuntary contraction of the urethral and/or periurethral striated muscles typically occurring in a patient with a spinal cord lesion above the sacral cord. Consequently, high urethral closure pressures during the detrusor contraction leads to high intravesical voiding pressure and large postvoid residuals, which can lead to significant complications in up to 50% of patients if DSD is not treated and followed-up regularly. DSD treatment options are centered around symptomatic management rather that addressing the underlying causative mechanisms.

Prostatic stents: a narrative review of current evidence

Benign prostatic hyperplasia (BPH) is a common chronic urologic condition affecting approximately 50% of men above the age of 60. As per European Association of Urology Guidelines, BPH can be treated according to a stepwise approach starting from a conservative management, a pharmacologic approach, and finally surgery. Both medical and surgical therapies have side effects, impacting on ejaculation and sexual function and patients with multiple comorbidities might not be considered surgically suitable candidates. Prostatic stents offer a minimally invasive procedures in an out-patient setting, possibly under local anaesthesia. Utilized since the 1980s, the past stents encompassed permanent (epithelializing) or temporary (non-epithelializing) devices, like the Uro-Lume (American Medical Systems, Minnetonka, MN, USA) and the Memokath, or Memotherm (Engineers & Doctors A/S, Denmark), and the biodegradable stents made of self-reinforced poly-L-lactide or braided poly lactic-co-glycolic acid. Previous stents however showed a quite high rate of complications among which pain, incontinence, infections, stent migration or blockage, and incomplete degradation that might lead to premature removal of stent. The stents currently available on the market instead are the temporary device Allium Triangular Prostatic Urethral Stent (Allium Urological Solutions, Caesarea, Israel) and the temporary stent SPANNER (AbbeyMoor Medical, Inc., Parkers Prairie, MN, USA), which might be used in case of bladder outflow obstruction, post-operatively, or for acute urinary retention. Studies showed encouraging results, in terms of effectiveness and safety improving patients' quality of life and International Prostate Symptom Score, but longer-term studies are needed to identify the most suitable patients who might benefit from their use. Newer stents and nitinol devices are currently investigated, and we are waiting for the results of the ongoing clinical trials.

The accumulation of particles in ureteric stents is mediated by flow dynamics: Full-scale computational and experimental modeling of the occluded and unoccluded ureter

Ureteric stents are clinically deployed to restore urinary drainage in the presence of ureteric occlusions. They consist of a hollow tube with multiple side-holes that enhance urinary drainage. The stent surface is often subject to encrustation (induced by crystals-forming bacteria such as Proteus mirabilis) or particle accumulation, which may compromise stent's drainage performance. Limited research has, however, been conducted to evaluate the relationship between flow dynamics and accumulation of crystals in stents. Here, we employed a full-scale architecture of the urinary system to computationally investigate the flow performance of a ureteric stent and experimentally determine the level of particle accumulation over the stent surface. Particular attention was given to side-holes, as they play a pivotal role in enhancing urinary drainage. Results demonstrated that there exists an inverse correlation between wall shear stress (WSS) and crystal accumulation at side-holes. Specifically, side-holes with greater WSS levels were those characterized by inter-compartmental fluid exchange between the stent and ureter. These "active" side-holes were located either nearby ureteric obstructions or at regions characterized by a physiological constriction of the ureter. Results also revealed that the majority of side-holes (>60%) suffer from low WSS levels and are, thus, prone to crystals accumulation. Moreover, side-holes located toward the proximal region of the ureter presented lower WSS levels compared to more distal ones, thus suffering from greater particle accumulation. Overall, findings corroborate the role of WSS in modulating the localization and extent of particle accumulation in ureteric stents.

Clinical guidelines for the diagnosis and treatment of lower urinary tract dysfunction in patients with spinal cord injury

The present article is an abridged English translation of the Japanese clinical guidelines for the diagnosis and treatment of lower urinary tract dysfunction in patients with spinal cord injury updated as of July 2019. The patients are adult spinal cord injured patients with lower urinary tract dysfunction; special consideration of pediatric and elderly populations is presented separately. The target audience is healthcare providers who are engaged in the medical care of patients with spinal cord injury. The mandatory assessment includes medical history, physical examination, frequency-volume chart, urinalysis, blood chemistry, transabdominal ultrasonography, measurement of post-void residual urine, uroflowmetry and video-urodynamic study. Optional assessments include questionnaires on the quality of life, renal scintigraphy and cystourethroscopy. The presence or absence of risk factors for renal damage and symptomatic urinary tract infection affects urinary management, as well as pharmacological treatments. Further treatment is recommended if the maximum conservative treatment fails to improve or prevent renal damage and symptomatic urinary tract infection. In addition, management of urinary incontinence should be considered individually in patients with risk factors for urinary incontinence and decreased quality of life.

[Temporary urethral stents changes as an alternative treatment for neurological bladder]

BACKGROUND

Patients with detrusor-sphincter dysynergia (DSD) who are unable to perform self-catheterisation can benefit from an endoscopic treatment. We chose regular urethral stent changes as an alternative to sphincterotomy in this kind of patients. The purpose of this study is to show that temporary urethral stents changes represent a treatment option with a reasonable morbidity for patients with DSD.

METHODS

We retrospectively reviewed patients in our center who had been treated with urethral stents from April 2005 to September 2017. The stent changes were performed every 12 to 18 months depending on urethrovesical fibroscopy findings. The primary endpoint was treatment continuation.

RESULTS

A total of 44 patients were enrolled in our study and the average follow-up duration was 46 months [18.5-53.25]. Primary treatment failure was seen in 14 (32%) patients mainly due to problems related to equipment (n=3) and urinary retention (n=2). Four patients died before their first stent change. The treatment was successful in 30 (68%) patients, of whom 10 (33%) subsequently adopted a voiding mode change. We lost sight of 5 patients (11%) during follow-up. The main complications were urinary retention (29%), urinary tract infections (27%) and stent migration (18%). Fifteen (34%) experienced grade III-IV complications.

CONCLUSIONS

Regular urethral stent changes represent an alternative treatment option for patients with DSD but with a significant morbidity.

LEVEL OF EVIDENCE

4.

Urethral Stenting for Obstructive Uropathy Utilizing Digital Radiography for Guidance: Feasibility and Clinical Outcome in 26 Dogs

Background

Urethral stent placement is an interventional treatment option to alleviate urethral outflow obstruction. It has been described utilizing fluoroscopy, but fluoroscopy is not as readily available in private practice as digital radiography.

Objectives

To describe the use of digital radiography for urethral stent placement in dogs with obstructive uropathy.

Animals

Twenty‐six client‐owned dogs presented for dysuria associated with benign and malignant causes of obstructive uropathy that underwent urethral stent placement.

Methods

Retrospective study.

Results

Causes of obstructive uropathy included transitional cell carcinoma, prostatic carcinoma, hemangiosarcoma, obstructive proliferative urethritis, compressive vaginal leiomyosarcoma, and detrusor‐sphincter dyssynergia. Survival time range was 1–48 months (median, 5 months). All dogs were discharged from the hospital with urine outflow restored. Intraprocedural complications included guide wire penetration of the urethral wall in 1 dog and improper stent placement in a second dog. Both complications were successfully managed at the time of the procedure with no follow‐up problems noted in either patient.

Conclusion and Clinical Importance

Urethral stent placement can be successfully performed utilizing digital radiography. The complications experienced can be avoided by more cautious progression with each step through the procedure and serial radiography. The application of digital radiography may allow treatment of urethral obstruction to become more readily available.

[Temporary urethral stents ALLIUM BUS "BULBAR URETHRAL STENT" for the treatment of detrusor sphincter dyssynergia]

INTRODUCTION

The temporary prosthetic sphincterotomy is a possible treatment for neurologic detrusor sphincter dyssynergia (DSD). The purpose of the study was to verify the feasibility and effectiveness of the urethral stent (US) Temporary ALLIUM BUS "BULBAR URETHRAL STENT".

PATIENTS AND METHODS

A prospective, non-comparative, single-center starting in 2015 was conducted. Were included patients over 18 years, with a neurologic DSD proved urodynamically for which medical treatment was not indicated or failed. The primary endpoint was the percentage of patients who had a voiding method considered as improved or much improved at 1 month and the feasibility of the procedure.

RESULTS

From January to June 2015, 7 patients, (mean age 47.9 years [24-76 years]) were prospectively enrolled. One patient was lost to sight at one month and therefore excluded. The median follow-up was 8.1 months (1-10 months). All procedures were technically successful. At 1 month, there were 57% of grade 2 complications (Clavien-Dindo), 1 of 6 patients had a migration of the US. At one month, quality of life and the urologic situation was considered good in 3 patients, unchanged in 2 patients and decreased in 1 patient. The study was stopped after the inclusion of seven patients. At the date of the latest news, 5 of 6 patients had a migrated or an explanted US.

CONCLUSION

The temporary urethral stent ALLIUM BUS does not seem to be a possible surgical alternative for the treatment of detrusor sphincter dyssynergia.

LEVEL OF EVIDENCE

4.

Detrusor sphincter dyssynergia: a review of physiology, diagnosis, and treatment strategies

Detrusor sphincter dyssynergia (DSD) is the urodynamic description of bladder outlet obstruction from detrusor muscle contraction with concomitant involuntary urethral sphincter activation. DSD is associated with neurologic conditions such as spinal cord injury, multiple sclerosis, and spina bifida and some of these neurogenic bladder patients with DSD may be at risk for autonomic dysreflexia, recurrent urinary tract infections, or upper tract compromise if the condition is not followed and treated appropriately. It is diagnosed most commonly during the voiding phase of urodynamic studies using EMG recordings and voiding cystourethrograms, although urethral pressure monitoring could also potentially be used. DSD can be sub-classified as either continuous or intermittent, although adoption of this terminology is not widespread. There are few validated oral pharmacologic treatment options for this condition but transurethral botulinum toxin injection have shown temporary efficacy in reducing bladder outlet obstruction. Urinary sphincterotomy has also demonstrated reproducible long term benefits in several studies, but the morbidity associated with this procedure can be high.

Neurogenic bladder in spinal cord injury patients

Neurogenic bladder dysfunction due to spinal cord injury poses a significant threat to the well-being of patients. Incontinence, renal impairment, urinary tract infection, stones, and poor quality of life are some complications of this condition. The majority of patients will require management to ensure low pressure reservoir function of the bladder, complete emptying, and dryness. Management typically begins with anticholinergic medications and clean intermittent catheterization. Patients who fail this treatment because of inefficacy or intolerability are candidates for a spectrum of more invasive procedures. Endoscopic managements to relieve the bladder outlet resistance include sphincterotomy, botulinum toxin injection, and stent insertion. In contrast, patients with incompetent sphincters are candidates for transobturator tape insertion, sling surgery, or artificial sphincter implantation. Coordinated bladder emptying is possible with neuromodulation in selected patients. Bladder augmentation, usually with an intestinal segment, and urinary diversion are the last resort. Tissue engineering is promising in experimental settings; however, its role in clinical bladder management is still evolving. In this review, we summarize the current literature pertaining to the pathology and management of neurogenic bladder dysfunction in patients with spinal cord injury.

Dysfunction of lower urinary tract in patients with spinal cord injury

Over the past 50 years, the mortality for urorenal cause in patients with spinal cord injuries (SCI) has decreased from over 75% to 2.3%, as a result of dramatic improvements in the diagnosis and management of lower urinary tract dysfunction (LUTD). The aims of this chapter are to assess the physiopathology of upper and lower motor neuron lesion on bladder and sphincter function after SCI, to give an overview of required clinical and instrumental examination and to discuss treatment modalities. Videourodynamic examination plays a key role in the assessment and follow-up of LUTD in SCI patients, in conjunction with neurophysiological and radiological examinations. The cornerstone of bladder management in SCI is clean intermittent self-catheterization, but often other treatments are needed to achieve full continence, to reduce infections and stone formation, to protect the upper urinary tract from excessive bladder pressure, and to prevent chronic renal failure. Treatments may be pharmacologic (i.e., anticholinergic drugs and botulinum toxin) or surgical (by enterocystoplasty or urinary diversion). In selected cases, neuromodulation and sacral root stimulation can be used to reduce detrusor overactivity and empty the bladder. Management of LUTD in SCI patients requires a deep knowledge of spinal cord medicine and functioning of patients with neurologic disability.

Early experience with a thermo-expandable stent (memokath) for the management of recurrent urethral stricture

Purpose

To report our early experience with thermo-expandable urethral stents (Memokath) for the management of recurrent urethral stricture and to assess the efficacy of urethral stents.

Materials and Methods

Between March 2012 and February 2013, 13 patients with recurrent urethral stricture after several attempts with direct visual internal urethrotomy (DVIU) or failed urethroplasty underwent DVIU with thermally expandable, nickel-titanium alloy urethral stent (Memokath) insertion. Follow-up study time points were at 1, 3, 6, 9, and 12 months after stent insertion. Follow-up evaluation included uroflowmetry, retrograde urethrogram, plain radiography, and urinalysis.

Results

The mean patient age was 47.7 years (range, 18 to 74 years). The mean urethral stricture length was 5.54 cm (range, 1 to 12 cm). There were six patients with bulbar, four patients with proximal penile, one patient with distal penile, and two patients with whole penile urethral strictures, respectively. The overall success rate was 69% (9/13) and the mean postoperative peak flow rate was 17.7 mL/s (range, 6 to 28 mL/s). Major complications occurred in four patients including one patient (7.7%) with urethrocutaneous fistula induced by the stent and three patients with urethral hyperplasia. The mean follow-up duration was 8.4 months.

Conclusions

Our initial clinical experience indicates that thermo-expandable stents can be another temporary management option for recurrent urethral stricture patients who are unfit for or refuse urethroplasty. Distal or whole penile urethral stricture can be factors predicting poor results.

Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures: To use or not?

Objectives

To assess the role of temporary thermally expandable urethral stents in maintaining urethral patency in patients with a recurrent bulbar urethral stricture.

Patients and methods

Twenty-three men with a recurrent bulbar urethral stricture after several attempts at direct visual internal urethrotomy (DVIU) and/or failed urethroplasty were managed with a thermally expandable, biocompatible nickel–titanium alloy urethral stent (Memokath® MK044, Pnn Medical, Kvistgaard, Denmark). The stents were applied by a special mounting device via a rigid urethroscope after DVIU. All patients were followed using plain radiography, uroflowmetry and urine analysis every 3 months for 1 year, and then every 6 months.

Results

The mean (SD) age of the patients was 55.4 (7.3) years and the mean (SD) stricture length was 3.6 (1.2) cm. All patients tolerated the stent, with minimal discomfort in some patients. Four patients (17%) had urinary tract infections, three (13%) had haematuria, three (13%) had obstructed stents due to encrustation, in five (22%) the stent migrated, and two patients had no delayed complications. The mean (SD) follow-up was 17.4 (6.1) months.

Conclusion

Urethral stenting with nickel–titanium alloy thermally expandable stents can be an acceptable temporary procedure for patients with recurrent bulbar urethral strictures who are unfit for or who refuse urethroplasty. However, they have limitations; the search for an ideal urethral stent continues.

[Treatment of detrusor-striated sphincter dyssynergia with permanent nitinol urethral stent: results after a minimum follow-up of 2 years]

OBJECTIVES

The aim of this study was to assess the outcomes of nitinol permanent urethral stents used in detrusor-striated sphincter dyssynergia (DSD) treatment on male patients with a spinal cord injury.

MATERIALS

We investigated retrospectively all patients treated from 2004 to 2012. A total of 22 patients were included, with an age ranging from 22 to 76 years old. The DSD syndrome was due to spinal cord injury (18) or various spinal cord diseases (four) and treated with a nitinol urethral stent (11 Ultraflex(®) and 11 Mémotherm(®)). Every patient had an urodynamical study. The follow-up reached at least 2 years.

RESULTS

The mean follow-up was 56 months (± 14). Complementary procedures after stenting included: five stent prolongation or displacement (mean interval 7.6 months), six bladder neck incisions (12.2 months), three urethrotomy (42 months), ten obstruction treated by laser (47.3 months). Eight patients had a change of their urinary pattern: four underwent ileal conduit diversion, one had a continent urinary diversion, one chose self intermittent catheterization, two were under indwelling catheterization waiting for another treatment. Stent retrieval was either harmful or impossible for four of them. Three patients were free of complementary procedures.

CONCLUSIONS

Nitinol urethral stent was an effective treatment initially. However, by the third year, urethral stenosis and hypertrophic growth of the urethral mucosa usually require iterative endoscopic procedures (0.31 per patient per year). Patients treated with permanent uretral stent deserve a yearly endoscopic follow-up. Safety and effectiveness of permanent uretral stent compared to surgical sphincterotomy to treat DSD are discussed.

Spinal cord/brain injury and the neurogenic bladder

This article reviews neurogenic bladder related to traumatic injury as well as vascular lesion of brain/spinal cord. Because urological manifestations of traumatic or vascular brain/spinal cord injury are highly diversified and complex, the approaches to achieve accurate diagnosis and administer proper treatment can be complicated. The goal of primary treatment is preservation of renal function and attainment of social continence. Maintaining low intravesical pressure and adequate bladder emptying are central to the treatment strategy. Diagnosis and appropriate urological management of these disease entities should depend on urodynamic studies because of poor correlation between clinical symptoms or somatic neurologic signs and urodynamic findings.

Clinical usefulness of the memokath stent as a second-line procedure after sphincterotomy failure

PURPOSE

To assess the clinical usefulness of Memokath® stent placement in the external sphincter region in men with neurogenic bladder dysfunction from spinal cord injury after failed sphincterotomy.

PATIENTS AND METHODS

Twenty-two men with elevated (> 100 mL) residual urine and/or voiding difficulties/autonomic dysreflexia were treated with a Memokath stent. Follow-up examinations comprised residual urine, video-urodynamics, renal sonography, and assessment of subjective outcome.

RESULTS

No intraoperative complications were observed. Transient autonomic dysreflexia developed in one patient. Stent repositioning from dislocation was necessary in four (18.2%) patients. After a median follow-up of 10.3 months, 18 (81.8%) patients still had a stent in place. In two men, the stents were removed because of newly diagnosed urothelial bladder cancer; in another two patients, they were removed because of lack of success. At follow-up, residual urine was significantly reduced from 229 to 105 mL. Residual urine was < 100 mL in 14 of 18 (77.8%) patients. Changes in bladder capacity, detrusor leak point pressure, bladder compliance, and maximum detrusor pressure were not statistically significant. Renal sonography did not reveal any pathologic findings.

CONCLUSIONS

According to our data, the Memokath stent is not only an alternative treatment option to sphincterotomy, but it is a safe and successful second-line treatment after sphincterotomy failure.

Managing the urinary tract in spinal cord injury

This review sets out to provide an overview of the author's approach to the management of the urinary tract in the patient who has suffered from an injury to their spinal cord. Emphasis is given to the need to understand the fundamental pathophysiological patterns that are seen with injuries that involve the sacral segments of the cord (the conus) and those that spare the conus but interrupt communication between the sacral parasympathetic and somatic centers and the brain (supraconal lesions). The importance of patient participation in management decisions is highlighted by considering the different ways in which the urinary tract can be managed and how the clinician needs to try to meet patient expectations and requirements while establishing safe urological management. Finally, consideration is given to the importance of establishing an appropriate follow up regime and managing urinary tract complications effectively.

Outcome after treatment of detrusor–sphincter dyssynergia by temporary stent

OBJECTIVES

To evaluate follow-up treatments used after treatment of detrusor-sphincter dyssynergia (DSD) by a temporary urethral sphincter stent.

MATERIALS AND METHODS

Between February 1994 and June 2003, 147 men with a mean age of 41.3+/-14.4 years were treated by temporary urethral stent inserted across the external sphincter for DSD. The underlying neurologic disease was quadriplegia in 85 cases, multiple sclerosis in 24 cases and paraplegia in 21 cases. A Nissenkorn (Bard) stent was used in 130 cases and a Diabolo (Porgès) stent was used in 17 cases. All patients were either unable to or they refused to perform intermittent self-catheterization. DSD was demonstrated by urodynamic studies in every case.

RESULTS

The mean duration of temporary stenting was 10.15+/-16.07 months. After temporary stenting, 92 patients were treated by permanent stent (Ultraflex, Boston Scientifics), 7 started intermittent self-catheterization, 12 had repeated changes of the temporary stent, 4 had an indwelling catheter, 3 underwent cystectomy with non-continent diversion, 2 were treated by endoscopic sphincterotomy, 1 was treated by bladder neck incision, 1 was treated by neuromodulation and 1 was treated by cystostomy. Fifteen patients were lost to follow-up. Two patients died during follow-up (not related to DSD).

CONCLUSION

After treatment of DSD by a temporary urethral sphincter stent, 70.7% of patients subsequently require a permanent urethral sphincter stent. This period allows selection of patients unlikely to benefit from permanent urethral sphincter stent.

Long-term follow-up study of intraurethral stents in spinal cord injured patients with detrusor-sphincter dyssynergia

STUDY DESIGN

Retrospective study.

OBJECTIVES

To assess in the long-term clinical and urodynamic results of intraurethral stents in a group of patients with spinal cord injury.

SETTING

Spinal Cord Injury Unit, Juan Canalejo Hospital, A Coruña, Spain.

METHODS

Forty-seven consecutive male patients were studied from 1993 to 2002. All of them suffered from hyperreflexia with detrusor-sphincter dyssynergia (DSD) owing to spinal cord injury, and were treated by means of the placement of an intraurethral stent at the external sphincter.

RESULTS

After surgery, significant decreases in all the parameters studied were observed. The number of patients with symptoms of urinary tract infection decreased by 25% (P<0.031). Post-void residual urine volume experienced an average decrease of 224.3 cm(3) (P=0.001). Episodes of dysreflexia decreased from 35.1 to 16.2% (P=0.039). The urodynamic study showed an average reduction of 44.36 cm H(2)O in the maximum detrusor pressure (P<0.0001). Complications in the upper urinary tract descended from 46.8 to 23.4% after placing the stent (P=0.013). The most frequent stent complication was displacement, followed by stenosis, lithiasis and intraprosthetic calcification. In all, 8.5% required the stent removal.

CONCLUSIONS

Intraurethral stent is a good choice for the long-term management of DSD in spinal cord-injured patients, even in those who had been previously submitted to prior sphincterotomy. It has the advantage of being a potentially reversible procedure, so patients prefer it to more invasive therapies such as sphincterotomy.

Management of detrusor-external sphincter dyssynergia

Detrusor-external sphincter dyssynergia (DSD) is a debilitating problem in patients with spinal cord injury. DSD carries a high risk of complications, and even life expectancy can be affected. The mainstay of treatment is the use of antimuscarinic medication and catheterization, but in those for whom this is not possible external sphincterotomy has been the traditional management route. External sphincterotomy, however, is associated with significant risks, including hemorrhage, erectile dysfunction and the need for repeat procedures, and over the last decade alternatives have been investigated, such as urethral stents and botulinum toxin injection. We present a review of DSD, including the current management strategies and prospects for future treatment.