This is the first preclinical study in the literature performed in a large animal model in which a new design of chemotherapy eluting biodegradable ureteral stent for the adjuvant treatment of UTUC (upper tract urothelial carcinoma) is assessed. As is well known, currently one of the main limitations in patients with UTUC who are managed conservatively is the difficulty when it comes to instilling chemotherapy or immunotherapy in the upper urinary tract. As a result, adjuvant therapy is often not performed. The development of new drug delivery technologies promises to change this paradigm by favoring upper tract exposure to the drug, leading to greater treatment efficacy.

The experimental study assesses a silk fibroin-coated biodegradable ureteral stent for mitomycin delivery, the BraidStent-SF-MMC, in a porcine animal model. The ureteral stent was placed retrograde and released mitomycin during the first 12 h. The stents were completely degraded at 6-7 weeks and were excreted without obstructive fragments via the urinary tract. There were no stent-related systemic toxic effects. The success rate was 67.5% and the complication rate was 25.7%, related to urinary pH<7.0, which destabilized the stent coating. Authors consider that future patients should have dietary indications during the first 3 weeks post-stenting to maintain their urinary pH>7.0. It would also be useful to regularly measure urine pH with a portable electronic pH-meter like Lit-Control® pH Meter as recently suggested in patients with urolithiasis, for an exhaustive control of urinary pH.

For the first time, the authors of this work have demonstrated that a biodegradable cancer drug-eluting stent, BraidStent-SF-MMC, provides a controlled and well-tolerated release of mitomycin into the upper urinary tract in an animal model. Mitomycin release from a silk fibroin coating could be a compelling approach for adjuvant chemotherapy instillation in the treatment of upper tract urothelial carcinoma. This is an important first step on the way to finding new approaches to local instillation of chemotherapy for adjuvant UTUC.

Encrustation of ureteral stents may be a complex challenge to manage by endourology approach. Unfortunately, patients may require multiple procedures, as well as several surgical sessions to resolve the encrustation.

The authors of this study assess outcomes in a series of 58 patients. The majority of patients, 56.9%, had the ureteral stent for 6-12 months, while 22.4% and 20.7% had the ureteral stent for less than 6 months and more than 12 months, respectively.

As is usual, the authors find the encrustation mainly in the proximal pigtail, 29.3% of stents also showed bladder pigtail encrustation and, less commonly had encrustations in the whole length. All ureteral stents were successfully retrieved. In 89.7% of the cases, ureteral stents were removed in a single session by URS or fURS; 7% of the cases a two-stage procedures fURS followed by a PCNL in a second session and 3.4% encrustation was managed by ECIRS.

As the authors comment, in an area of poorly defined indications and techniques, sharing surgical knowledge is crucial to improve outcomes. The authors present their step-by-step approach to ureteral stent encrustations in this interesting manuscript, providing urologists with helpful information. The paper describes maneuvers such as cutting the stent with laser and retrieve the pieces if the proximal part cannot be released, introducing a safety and a working guidewire, and choosing different techniques depending on the location of the encrustation.

An interesting clinical study on the effects of ureteral stents with a clear patient’s perspective and above all showing the inability of current questionnaires to assess certain effects, mainly related to psychological aspects.

The authors conduct individual interviews with 39 patients in order to get them to share their symptoms with a post-ureteroscopy stent (range 7–30 days) and described symptom bother and impact on daily activities.

All participants reported experiencing pain, but they used a variety of attributes to describe their pain experience. Nearly all participants mentioned having blood in their urine, increased urinary frequency and urinary urgency. Participants’ narratives also reflected a significant decline in overall enjoyment of life while the stent was in place, including emotional distress caused by anxiety. Unfortunately, participants described this time as a continuation of their experience with developing kidney stones. It is noteworthy that in this study most patients report that during the time of stenting they remained on sick leave. Participants shared that having the stent in place affected more of their daily living activities than they had initially anticipated.

Thus, we have two significant findings in this study, firstly the weight of patient evidence of deterioration on their psychological health and the evidence that current questionnaires do not adequately assess this impact. Secondly, and already demonstrated previously, the importance of educating patients to understand the symptomatology associated with ureteral stents, to reduce the anxiety and pain associated.