Hello and welcome to the Stone News, a newsletter where we discuss every two months the most recent and relevant studies in stone disease.

Suscribe now

In this ninth newsletter, I would like to share with you three recent manuscripts that update us and provide new evidence on the adverse effects of ureteral stents. 

The selection includes an extraordinary study evaluating the use of antibiotics associated with ureteral stents, as prophylaxis, during stenting and after removal. 

This links perfectly with the clear need to define protocols and avoid bacterial resistance. 

I hope you enjoy this information and its applications in patients.

3'

In this new paper related to ureteral stents the authors carry out a prospective clinical study to assess the adverse effects in patients with ureteral stents on sexual function. It is clear that this issue has already been assessed in previous scientific manuscripts, and we already know that there is a clear adverse effect on sexual function.

The innovative and interesting point of this paper is related to the inclusion of both men and women, with confirmed sexual activity. Also, the aim of the study is not exclusively to assess sexual dysfunction associated with ureteral stents, but also when there is a recovery of sexual function similar to that prior to ureteral stenting. 

In addition, the authors assessed men (IIEF-5, International index of erectile function questionnaire) and women (FSFI, Female sexual function index) with different validated questionnaires. The inclusion criteria are strict and promote scientific evidence in this study: sexually active patients aged 20-55 years; unilateral indwelling ureteral stents placed postoperatively with stent removal within 1 month; the preoperative IIEF-5 score of ≥ 22 for male patients, and FSFI score of ≥ 26.55 for female patients.

The first striking finding is that 73% male patients and 71% female patients attempted sexual contact and the remaining patients avoided sexual intercourse because of fear. Statistically significant differences were found between male and female patients with respect to baseline score values versus the ureteral stenting period and a clear recovery to baseline values 4 weeks after ureteral stent removal, and 6-8 weeks after stent removal if their personal recovery was poor.

However, 7% of the women denied any sexual activity for 4 weeks after removing their ureteral stents because of the psychological stress. No scabbing, infections, or stent dislodgement were observed in any of the patients, which allows us to rule out such causes and reduce bias in this study. After assessment of the results, the authors discuss an important fact that differentiates men from women, namely that the primary factors affecting sexual function in male patients are pain and lower urinary tract symptoms, while in female patients, psychological factors play a major role.

So the conclusions of this manuscript are important for clinical application: Patients need a lot of detailed education to understand their possible stent-associated symptomatology; it is important to alleviate psychological stress, and of course reduce postoperative discomfort. All associated with shortening the stenting time for patients. 

2'

This second selected paper is a superb literature review focused on evaluating the available literature on stent-related infections, the use of antibiotics and bacterial colonisation to identify the current incidence of symptomatic stent-related infections, unveil knowledge gaps, and generate potential hypotheses for future stent-related infection research. 

It therefore addresses an issue of great interest, as there is a clear lack of scientific evidence in decision-making regarding the use of antibiotics in patients with ureteral stents, which leads to major clinical problems and also to unjustified health care costs. The study focuses mainly on answering the following questions: the use of antibiotics at time of stent placement, during indwelling time, at stent removal or exchange, and best practice during a UTI with a ureteral stent in situ.

The use of antibiotics at time of stent placement:

Authors still advocate to have a urine culture before any urological procedure, a positive urine sample does not seem to increase the risk of UTI for the procedure of stent placement or exchange. With a very low risk of UTI with or without antibiotic prophylaxis regardless of the outcome of a preoperative urine culture, antibiotic prophylaxis may thus be obviated for this procedure. This urine culture may help guide antibiotic therapy if postoperative UTI is encountered.

Despite the lack of good quality data and the fact that it does not seem to influence postoperative UTI rate, antibiotic prophylaxis is still recommended by the guidelines prior to URS. In case of a preoperative negative urine culture, it may be considered to only give antibiotic prophylaxis in the presence of risk factors (e.g., Diabetes Mellitus, prolonged procedure, etc.).

Antibiotic prophylaxis during indwell time does not show any advantage and its use for this indication cannot be supported. 

Antibiotic Prophylaxis at Time of Stent Removal:

The value of routine antibiotic prophylaxis should be questioned. There is no strong evidence to support the use of antibiotics in this setting and even in high-risk patients (kidney transplant patients) no significant difference was found. Most urologists who do give antibiotic prophylaxis at time of stent removal provide only a single dose, which has been shown not to be effective.

Management of UTI and stents during a stent-related infection with the stent in situ. No clear evidence is available and hence no guidelines exist on how to manage UTI in patients with indwelling stents. To remove the biofilm as a potential source of bacteria in frequently recurring infections, a stent exchange during antibiotic therapy could be considered.

The value of stent culture and urine culture in patients with ureteral stents:

In pre-stented patients, a preoperative urine culture is important to guide antibiotic prophylaxis. An additional stent culture can be considered in patients with risk factors, such as diabetes mellitus, chronic renal failure, and dwell time, when removing the stent. As urine culture and stent culture can differ, this stent culture can help to guide future antibiotic treatment if the patient develops a UTI. 

2'

I consider this recent paper to be of great interest as it is outside the point of view of the urologist and even ureteral stent researchers, which provides a different view that is of great interest for the understanding of the adverse effects of stents. 

The aim of this study is to summarize medical device reports (MDRs) between 2012 and 2022 relating to stents within the Manufacturer and User Facility Device Experience (MAUDE) database maintained by FDA.

The MAUDE database represents the most widely utilized reporting system for medical device-related side events. Each year, the FDA receives medical device reports detailing associated side events, including deaths, injuries, and malfunctions. These reports are submitted by manufacturers, device user facilities, and voluntary reports from healthcare providers, patients, and consumers. 

The number of reports identified was 2.652 with the number of reports considerably increasing every year between 2019 and 2021. Among these reports, 31% were related to injury, 68% to device malfunctions (68%), and there were 0.1% events of death. The most frequently reported specific adverse events included stent breakage in 23% cases, material problems in 14% reports, calcification in 8% reports, and difficulty in inserting, advancing, or removing the device in 6% reports. Analysis of these reports indicates a higher risk of breakage when the indwelling period is extended or when performing procedures like ESWL.

The pity of these results and this database is that it does not allow contextualisation of the overall adverse effects, as it would be necessary to know the worldwide number of annual ureteral stents that are placed. Although estimates from 2 years ago are that annually, over 1.5 million ureteral stents are used worldwide. 

Thus, the values of associated adverse effects reported in this database are very low, although of course, the manufacturers' reports are voluntary.