Ureteral stents and their use in endourology

Management of 'forgotten' encrusted JJ stents using extracorporeal shockwave lithotripsy: A single-centre experience

Objective: To evaluate the role of extracorporeal shockwave lithotripsy (ESWL) for the management of ‘forgotten’ encrusted stents.

Patients and Method: This is a retrospective study of 133 patients with forgotten JJ stents, treated between January 2015 and January 2018. Encrustation was mainly found in the renal coil of the stent with distal concomitant encrustation in the vesical and/or ureteric segment. After laboratory and radiological assessment, treatment started with ESWL for the renal encrustation before successful extraction. Auxiliary endourological procedures were used for the encrusted vesical or ureteric segments. Failed cases underwent open surgery.

Results: The mean (SD; range) JJ stent indwelling time was 25.84 (10; 14–70) months. In all, 96 (72.2%) patients were seen after treatment for stone disease. In total, 94 patients (70.7%) were managed by ESWL monotherapy, whilst in 36 (27%) additional endourological procedures were required before successful extraction including: cystolithotripsy 19 patients (52.8%), ureteroscopic lithotripsy eight (22.2%), and percutaneous nephrolithotomy nine (25%). Open surgery was required in only three patients (2.3%). A mean of 0.28 procedures per patient was required before smooth stent extraction. The encrusted stents were removed after the first, second, third, and fourth ESWL sessions in 44 patients (33.1%), 43 (32.3%), 26 (19.5%), and 17 (12.8%), respectively. Patients with forgotten indwelling JJ stents for >2 years had significantly larger and harder encrustation at both JJ coils.

Conclusion: ESWL proved a feasible first-line treatment for forgotten encrusted JJ stents. The indwelling time of forgotten stents in the urinary tract is associated with greater encrustation burden, density and multiple sites of encrustation.

Abbreviations: CLT: cystolithotripsy; ESWL: extracorporeal shockwave lithotripsy; HU: Hounsfield unit; KUB: plain abdominal radiograph of the kidneys, ureters and bladder; PCNL: percutaneous nephrolithotomy; URL: ureteroscopic lithotripsy

Interventional Radiology and Interventional Endoscopy in Treatment of Nephroureteral Disease in the Dog and Cat

Interventional endoscopy and interventional radiology have led to the development of minimally invasive techniques for management of kidney and ureteral diseases in the dog and cat including idiopathic renal hematuria, ureteral obstruction, and ectopic ureters. Sclerotherapy is a renal-sparing chemical cauterization technique used in cases of idiopathic renal hematuria. Diagnosis of ureteral obstruction is challenging in some cases based on ultrasound alone and antegrade pyelography should be considered. Treatment options for obstructions include nephrostomy tubes, ureteral stents, and subcutaneous ureteral bypass devices. Treatment with cystoscopic-guided laser ablation provides similar outcomes to surgery in dogs with intramural ectopic ureters.

Flexible ureteroscopy: technique, tips and tricks

During the last decades, the surgical management of kidney stones benefited of many technological advances and one of them is the development of flexible ureteroscopy (fURS). This tool, ancillary equipment such as graspers and baskets, and lithotripsy technique with Holmium:YAG laser underwent many improvements leading to a widening of its indications with diagnostic and therapeutic management of upper urinary tract pathologies such as urolithiasis and urothelial tumors. The objective of this review is to describe the surgical technique for fURS as well as tips and tricks for the treatment of renal stones.

Safety and efficacy of silodosin and tadalafil in ease of negotiation of large ureteroscope in the management of ureteral stone: A prosective randomized trial

OBJECTIVE

To evaluate the safety and efficacy of silodosin and tadalafil in ease of negotiation of large size ureteroscope (8/9.8 Fr) in the management of ureteral stone.

MATERIAL AND METHODS

Between June 2015 and May 2016, 86 patients presented with ureteral stone of size 6-15 mm were on consent randomly assigned to 1 of 3 outpatient treatment arms: silodosin (Group A), tadalafil (Group B), and placebo (Group C). After two weeks of therapy 67 patients underwent ureteroscopy, and ureteral orifice configuration, ureteroscopic negotiation, ureteral dilatation, operating time, procedural complication and drug related side effects were noted in each group.

RESULTS

Ureteral negotiation was significantly better in Groups A (73.9%) and B (69.6%) as compared to Group C (38.1%) (p<0.01). Statistically significant difference was noted in the requirement for dilatation in Group C (71.4%) as compared to Groups A (26.1%) and B (39.1%) (p<0.01). Ureteral orifice was found to be more dilated in Groups A (69.6%) and B (60.9%) as compared to Group C (28.6%). Mean operating time was statistically lower in Groups A (35.2 min) and B (34.91 min) as compared to Group C (41.14 min) (p<0.01).

CONCLUSION

Both silodosin and tadalafil not only relax ureteral smooth muscle but also help in forward propagation of large size ureteroscope (8/9.8 Fr) without any significant risk of adverse events.

Extraction Strings for Ureteric Stents: Is There an Increased Risk for Urinary Tract Infections?

BACKGROUND

To evaluate urinary tract infections associated with placement of ureteric stents, we performed a retrospective study and compared rates between patients with and patients without an extraction string attached to the ureteric stent. Indwelling ureteric stents are routinely removed by cystoscopy. If an extraction string has been connected to the stent at the time of placement, however, the removal can be performed without an invasive procedure. Concerns exist regarding the risk for an unintentional dislocation, increased stent-related discomfort, or an increase of the post-operative urinary tract infection rate.

METHODS

All elective transurethral ureteric stent placements performed between November 2011 and December 2012 in our department were included for this investigation. Urinary tract infection was defined according to the Centers for Disease Control and Prevention (CDC)/National Healthcare Safety Network (NHSN) surveillance definition of health-care-associated infections. Patients with an existing urinary tract infection at the time of admission were excluded from the analysis.

RESULTS

A total of 342 patients receiving ureteric stents were evaluated regarding post-operative urinary tract infections. Of these patients, 127 (37.1%) had an extraction string and 215 (62.9%) a stent without a string. The total urinary tract infection rate was 6.4% with no significant difference between the two groups (7.9% vs. 5.6%, p = 0.49).

CONCLUSION

In the present study, we did not observe an increased rate of post-operative urinary tract infections in patients with an extraction string attached to the ureteral stent. Extraction string is a good option for patients to avoid cystoscopic stent removal.

PRISMA-combined α-blockers and antimuscarinics for ureteral stent-related symptoms: A meta-analysis

BACKGROUND

As a monotherpay, a-blockers and anti-muscarinics are both efficacy for ureteral stent-related symptoms (SRS). The aim of the study was to systematically evaluate their efficacy of a combination therapy for SRS.

METHODS

Relevant studies investigating α-blockers and/or anti-muscarinics for SRS were identified though searching online databases including PubMed, EMBASE, Cochrane Library, and other sources up to March 2016. The RevMan software was used for data analysis, and senesitivity analysis and inverted funnel plot were also adopted.

RESULTS

Seven randomized controlled trials (RCTs) and 1 prospective controlled trial including 545 patients were selected. Compared with α-blockers, the combination group achieved significant improvements in total International Prostate Symptom Score (IPSS) [-3.93 (2.89, 4.96), P < 0.00001], obstructive subscore [-1.29 (0.68, 1.89), P < 0.0001], irritative subscore [-2.93 (2.18, 3.68), P < 0.00001], and quality of life score [-0.99 (0.42, 1.55), P < 0.001]. Compared with antimuscarinics, there were also significant differences in total IPSS [-3.49 (2.43, 4.55), P < 0.00001], obstructive subscore [-1.40 (0.78, 2.01), P < 0.00001], irritative subscore [-2.10 (1.30, 2.90), P < 0.00001], and quality of life score [-1.18 (0.58, 1.80), P < 0.001] in favor of combination group. No significant difference was found in the visual analog pain score and the urinary symptoms score in Ureteral Stent Symptom Questionnaire (USSQ). No significant difference in complications was found.

CONCLUSIONS

Current analysis shows significant advantages of combination therapy compared with monotherapy of α-blockers or antimuscarinics alone mainly based on IPSS. More RCTs adopting validated USSQ as outcome measures are warranted to support the finding.

Nephroureteral Obstructions: The Use of Stents and Ureteral Bypass Systems for Renal Decompression

Canine and feline nephroureteral obstruction is a complex disease process that can be challenging to treat. Although the availability of various imaging modalities allows for a straightforward diagnosis to be made in most cases, the decision-making process for when a case should be taken to surgery and the optimal treatment modality that should be used for renal decompression remains controversial. In the following discussion, an overview of the perioperative management of cases with nephroureterolithiasis and nephroureteral obstruction is reviewed, with particular focus on the use of renal decompressive procedures, such as ureteral stenting and subcutaneous ureteral bypass system placement.

Extracorporeal shock wave lithotripsy in the primary treatment of encrusted ureteral stents

Double pigtail (JJ) ureteral stents, are the most commonly used method of urinary diversion in the ureteral obstructions. Encrustations may occur as a result of prolonged exposure due to forgetting these stents in the body. Removing these materials might be an annoyance. Forty-four patients from three tertiary referral centres with forgotten JJ stents left in them between the years 2007 and 2014 were included in the study. Stents could not be removed by attempted cystoscopy. As an alternative approach, extracorporeal shock wave lithotripsy (ESWL) was the first choice since it is minimally invasive. The results of that treatment are presented along with the relevant demographic data. JJ stenting for urolithiasis was performed in 36 patients, after open surgery in five patients, and for oncological reasons in three patients. ESWL was applied to stents or to any suspicious region adjacent to the stent. In 29 of 44 patients, the stents were easily removed under cystoscopic procedures while in one patient the fragmented residual stent was spontaneously excreted. In eight patients, ureteroscopy was required; in five patients, percutaneous nephrolithotripsy was required; and in one patient, open surgery was required in order to remove stents. ESWL can be considered as a first-line treatment when a forgotten JJ stent is detected despite all precautions after any kind of urological intervention involving insertion of ureteral stents.

"Bilateral Double J Stent Removal: The way to do it!"

There are many urological and non-urological indications which require bilateral double J stenting. We describe a point of technique for simultaneous removal of both the Double J stents. Both the stents are held by stent removing forceps at a point where they cross each other and then removed in one go with the help of cystoscope. Medline search did not reveal any techniques of removing two DJ stents in one go.

A preliminary study of the variability in location of the ureteral orifices with bladder filling by fluoroscopic guidance: the gender difference

BACKGROUND AND PURPOSE

To determine landmarks for stent positioning in both ureteral orifices (UOs) and the gender differences in their location in men and women.

PATIENTS AND METHODS

The location of the UO and the bladder neck (BN) was measured fluoroscopically by the intravesical distal location of an open-ended catheter marked with radiopaque materials. We compared the location in men (n = 12) and women (n = 12) with a full bladder (hydrostatic pressure of 50 cmH2O) or an empty bladder.

RESULTS

The mean distances from BN to UO in men and women were significantly different both in an empty bladder (2.5 ± 0.4 and 2.1 ± 0.3 cm, respectively) and in a full bladder (2.9 ± 1.0 and 2.3 ± 0.6 cm, respectively). The location of UO was changed by bladder filling in women but not in men. In women, most UOs were found superior to the symphysis pubis (SP) in empty bladder (66.6 %). Most of this location was observed at behind the upper boarder of SP in full bladder of women (75 %). The BN of women was located at the lower level in basal state compared to men. Also, the location of BN was markedly changed by bladder fulling in women (p = 0.04) but not in men.

CONCLUSIONS

Significant gender differences were observed in the location of UO and BN. Clinicians should keep in mind the anatomical differences between men and women during fluoroscopic-guided procedure.

Encrustation of urologic double pigtail catheters-an ex vivo optical coherence tomography (OCT) study

This study aims to evaluate whether optical coherence tomography (OCT) using both the surface and the endoluminal technique is feasible to investigate the locations and degree of encrustation process in clinically used ureteral stents. After removal from patients, 14 polyurethane JJ stents were investigated. A fresh JJ served as a control. The external surfaces were examined using an endoscopic surface OCT whereas the intraluminal surfaces were investigated by an endoluminal radial OCT device. The focus was on detection of encrustation or crystalline sedimentation. In 12 female and two male patients, the median indwelling time of the ureteral catheter was 100 days (range, 19-217). Using the endoluminal OCT, the size and grade of intraluminal encrustation could be expressed as a percentage relating to the open lumen of the reference stent. The maximum encrustation observed resulted in a remaining unrestricted lumen of 15-35 % compared to the reference. The luminal reduction caused by encrustation was significantly higher at the proximal end of the ureteral stent as compared to its distal part. The extraluminal OCT investigations facilitated the characterization of extraluminal encrustation. OCT techniques were feasible and facilitated the detection of encrustation of double pigtail catheters on both the extra and intra luminal surface. Quantitative expression of the degree of intraluminal encrustation could be achieved, with the most dense and thickened occurrence of intraluminal incrustation in the upper curl of the JJ stent.

Endoscopic placement of ureteral stents for treatment of congenital bilateral ureteral stenosis in a dog

CASE DESCRIPTION

A 5-year-old 8.6-kg (18.9-lb) spayed female Pug was evaluated because of chronic hematuria and recurrent urinary tract infections.

CLINICAL FINDINGS

Excretory urography, ultrasonography, and excretory CT urography were performed. Results indicated that the dog had bilateral hydronephrosis and hydroureter and suspected proximal ureteral stenosis. Retrograde ureteropyelography confirmed the presence of stenosis at the ureteropelvic junction of each ureter, along with a large amount of endoluminal ureteral debris. Clinical findings suggested that the dog had a congenital bilateral anomaly of the upper urinary tract.

TREATMENT AND OUTCOME

The dog was anesthetized, and 2 double-pigtail ureteral stents were placed cystoscopically with fluoroscopic guidance for immediate relief of the ureteropelvic junction obstructions. Each stent extended from the left or right renal pelvis to the urinary bladder. The procedures and the patient's recovery from anesthesia were uncomplicated. Continuing improvements in severity of hydronephrosis, hydroureter, and dysuria were evident during routine follow-up examinations at 2, 4, 12, 16, and 45 weeks after stent placement. Over the subsequent 12 months, all clinical signs remained resolved other than a urinary tract infection that was successfully treated with antimicrobials.

CLINICAL RELEVANCE

Ureteral stenosis should be considered as a differential diagnosis for hydronephrosis in dogs, particularly when urinary tract calculi or neoplasia is not present. Chronic hematuria and recurrent urinary tract infections can be associated with this condition. Placement of ureteral stents may be a successful treatment option for ameliorization of congenital ureteral obstructions.

Is stent placement necessary after uncomplicated ureteroscopy for removal of impacted ureteral stones?

BACKGROUND AND PURPOSE

Ureteral stent placement after ureteroscopic lithotripsy has some advantages and disadvantages. In this randomized study, the necessity of ureteral stent placement after uncomplicated ureteroscopy for impacted ureteral stones was assessed.

MATERIALS AND METHODS

Between 2005 and 2007, 60 evaluable patients were equally randomized to groups with and without stents. Patients underwent ureteroscopic pneumatic lithotripsy for ureteral stones. The operation was completed with or without stent placement according to the randomization order. Excretory urography was performed 3 months after the procedure. All stents were cystoscopically removed at the third postoperative week. Sociodemographic and clinical variables (age, sex, stone location, stone size, operative time, hospital stay, narcotic and nonnarcotic analgesic use), and postoperative complications (fever, pain delaying discharge, emergency department visit, urinary retention, stent-related irritative symptoms) were evaluated.

RESULTS

Mean stone size was not significantly different in both groups. Mean operative time was significantly longer in the stent group: 30.5 +/- 9.6 vs 43.7 +/- 11.6 minutes. On the operation day and until postoperative day (POD) 5, narcotic (P = 0.004) and nonnarcotic analgesic (P = not significant) use was more frequent in the no-stent group. At POD 5 and later, although narcotic and nonnarcotic analgesic use were frequently necessary in the stent group, both were almost unnecessary in the no-stent patients. Stent-related irritative symptoms were overwhelmingly higher (10% vs 93%) in the stent group. Discharge was delayed (23% vs 10%) and unplanned emergency department visits (20% vs 10%) were exercised almost two times more commonly in the no-stent group. Stone-free rates were identical (n = 29/30; 97%) in both groups.

CONCLUSION

Routine placement of a ureteral stent is not mandatory in patients without complications after ureteroscopic lithotripsy for impacted ureteral stones. Stent placement can be argued and agreed with the patients preoperatively in the light of the data presented above.

[Diagnostic and therapeutic ureteroscopy: is dilatation of ureteral meatus always necessary?]

OBJECTIVE

To assess the feasibility and safety of diagnostic or therapeutic semirigid ureteroscopy without ureteral meatus dilatation.

MATERIALS AND METHODS

A comparative, retrospective study was conducted of patients undergoing ureteroscopy from January 2000 to May 2008. For data analysis purposes, the population was divided into two groups based on whether ureteroscopy had been performed with (Group 1) or without (Group 2) ureteral meatus dilatation. Variables recorded included age, sex, type of procedure, surgical diagnosis, passive or active dilatation, number of stones, stone location, stone diameter, peroperative and postoperative complications, internal urinary diversion after the procedure, therapeutic success rate, operating time, and hospital stay duration. A 8-9.8 Fr Wolf semirigid ureteroscope was used. Descriptive statistics of the population and cohorts were performed, providing medians, quartiles, and limit values for non-normally distributed interval variables, and absolute and relative frequencies for categorical variables. Shapiro-Wilk's, Mann-Whitney's U, Chi-square, and Fisher's exact tests were used for statistical analysis. A value of p 2 alpha < or = 0.005 was considered statistically significant. Arcus Quickstat Biomedical 1.0 software was used.

RESULTS

Among the 306 ureteroscopies studied, 286 performed in 256 patients were analyzed. Median age was 50 years (16-83), 59% of patients were male, and elective ureteroscopy was performed in 183 patients (64%). Group 1: 191 ureteroscopies, Group 2: 95 ureteroscopies. Stone location: 149 in distal ureter, 60 in middle ureter, and 35 in proximal ureter. Sixty-nine percent of stones had sizes ranging from 5 and 10 mm. The overall success rate was 86.5%. There were 5 peroperative and 22 postoperative complications, with no statistically significant differences between the groups.

CONCLUSIONS

In selected cases, ureteroscopy may be performed without ureteral meatus dilatation with success and morbidity rates similar to when the procedure is performed with meatal dilatation.

[Plasma-deposited carbon coating on urological indwelling catheters: Preventing formation of encrustations and consecutive complications]

BACKGROUND

Any material placed in the urinary tract is susceptible to the formation of encrustations of crystalline bacterial biofilms. These biofilms cause severe complications in some cases. The strategies used so far for reduction of these complications by surface modifications of the implant material failed to show the expected results.

PATIENTS AND METHODS

In this study, we investigated amorphous carbon coatings (a-C:H) for their ability to effectively reduce or to repress the progressive formation of infection-enhancing crystalline biofilms as new functional surface coatings. In nine patients suffering for several years from stenting, a-C:H-coated ureteral stents were tested in treatment attempts. The current replacement intervals amounted to a mean of 77 days; the principle cause for early replacement was massive stent encrustations associated with symptomatic urinary tract infections.

RESULTS

In total, 20 coated ureteral stents were tested spanning indwelling times between 3 and 4 months. No stent-related complications occurred. In all cases extraordinarily facile handling, less pain during replacement, and markedly increased tolerance were observed. Symptomatic urinary tract infections were reduced by more than 50%. The stents remained virtually free of encrustations.

CONCLUSION

a-C:H coatings are a novel strategy leading to an enhancement of long-term applicability of ureteral stents and catheters and to improved patient comfort.

Novel dual-lumen ureteral stents provide better ureteral flow than single ureteral stent in ex vivo porcine kidney model of extrinsic ureteral obstruction

OBJECTIVES

In the instance of extrinsic ureteral obstruction, indwelling ureteral stents have a high failure rate. Although technically challenging, simultaneous insertion of two ipsilateral stents can achieve better flow rates with time. A novel dual-lumen stent, composed of two adhered ureteral stents, offers the additional benefit of easier placement than a single guidewire. Using a novel ex vivo porcine model, the flow rates within an extrinsically obstructed renal unit were evaluated using two internal ipsilateral stents and two prototype double-lumen stents.

METHODS

Sixteen renal units were harvested from eight adult Yorkshire female pigs. To quantify flow, the kidneys were infused at a constant pressure, and the corresponding ureteral drainage was measured for a defined interval. The flow was measured with a standard 7F double-pigtail stent, two ipsilateral 7F double-pigtail stents, a 7F novel double-lumen stent designed with both distal lumens open, and a 7F novel double-lumen stent with one distal lumen closed. The intraluminal and extraluminal flow in obstructed and nonobstructed systems was measured.

RESULTS

The two ipsilateral standard stents or prototype double stents achieved better flow down the ureter than did one standard stent (P <0.05). The intraluminal and extraluminal flow in the novel stents was statistically greater than the corresponding flow in the standard double-pigtail stent (P <0.01). The extraluminal and obstructed flow was lowest for the standard double-pigtail stent.

CONCLUSIONS

Novel dual-lumen prototype ureteral stents provided better flow than a single stent in extrinsically obstructed ureters with the proposed added benefit of easier retrograde insertion compared with a single guidewire.

Comparative study of ureteral stents following endoureterotomy in the porcine model: 3 vs 6 weeks and 7F vs 14F

The aim of the study was to determine the optimal stent size and stenting duration following retrograde endoureterotomy of experimental ureteral strictures. Twenty healthy Large White female pigs were randomly divided into four groups, depending on stent size (7F vs 14F) and stenting duration (3 weeks vs 6 weeks). Three additional pigs were used as the control group. The internal ureteral diameter was measured 2 cm below the lower pole of the right kidney. Histopathological changes of the urinary tract, ultrasonographic and fluoroscopic studies, urine culture, and serum urea and creatine levels were analyzed during the different phases of the study. The study was divided into three phases. Phase I included premodel documentation of the normal urinary tract and laparoscopic ureteral stricture creation. During the second phase 1 month later, the diagnosis and endourologic treatment of strictures were performed. Phase III began 4 weeks after stent removal; follow-up imaging studies and postmortem evaluation of all animals were performed. Ureteral strictures developed in all animals 4 weeks after model creation. Results from ureteral diameter measurements and pathological studies revealed no statistically significant intergroup differences. However, prevalence of urinary infection proved to be directly related to stent size (14F) and permanence (6 weeks). The chi square results suggest a statistically significant relationship between the urinary tract infection and recurrent strictures (alpha = 0.046). We recommend the use of 7F stents for a period of 3 weeks or less, as these are more easily positioned and result in the reduction of secondary side effects (lower infection rate, less intramural ureteral lesions). A significant relationship between urinary tract infection and stricture recurrence was found in this experimental study.

Clinical features determining the fate of a long-term, indwelling, forgotten double J stents

We review our experiences with forgotten stents and investigate the potential factors determining the degree of encrustation. Our series consists of nine cases of forgotten stent that had remained indwelling for more than 1 year (mean 36.1 months). We describe and compare their various clinical parameters in terms of encrustation. In addition, we briefly summarize our management schemes. All patients showed few stent related irritative symptoms. Six cases showing minimal or no encrustation shared the common feature of urine hypotonicity. Cystoscopic pullout was possible in these cases. The remaining three cases showed moderate to severe encrustation around the stent which required multiple procedures. Pyuria was observed in all cases and two patients had a history of urolithiasis. Finally, all cases were rendered stent and stone free. The fate of forgotten stents was dependent on the amount of encrustation around the stent. In our study, lithogenic history and presence of pyuria were associated with moderate to severe encrustation. Interestingly, patients showing urine hypotonicity tended to have a minimal encrustation on their stents and the stents were easily removed. Therefore, in patients with an impaired renal concentrating ability and a poor medical condition, the duration of indwelling stents might be safely prolonged if the patient has no risk factor for encrustation. As patients with forgotten stents are less likely to complain of stent related symptoms, thorough education of patients is important to prevent stent related complications.