Presently, selecting the most effective treatment for Ureteral Stenosis (US) in Kidney Transplant (KT) patients remains a topic of ongoing debate. While minimally invasive approaches have been employed for over 30 years [5], their significance has been revitalized with the advent of new technologies, particularly the utilization of various lasers in endourology [4].

Kristo et al. [2] reported a 100% success rate with a median follow-up of 24 months, but it's important to note that their study focused solely on short ureteral stenoses (US) with an average length of 2.8 mm. In our study, we extended the scope to include longer US with a median length of 10 mm

in contrast, previous studies have reported success rates for surgical reconstruction around 77% [6], which is comparable to the success achieved through endoscopic management.

However, surgical reconstruction tends to involve more intricate strictures and cases that have already proven resistant to endoscopic interventions—over half of the cases in our study had previously failed balloon dilation

A recent systematic review, encompassing 34 studies and 385 patients with distal ureteral strictures after kidney transplant, indicated success rates for surgical reconstruction reaching as high as 85.4% when utilized as the primary treatment and up to 93.1% as a secondary treatment following unsuccessful endoscopic interventions. In the same study, the endourological approach exhibited success rates of 64.3% and 75.5% for primary and secondary treatments, respectively. [7,8]

In 2017, Gil-Sousa et al. [5] presented a comprehensive 10-year experience at a single center regarding Ureteral Stenosis (US) after Kidney Transplantation (KT). Their study covered both reconstructive and endoscopic treatments, revealing no significant differences based on the length of stenosis, the duration between transplant and stenosis occurrence, or the location of the stenosis. However, a notable trend emerged, indicating a higher success rate for stenosis measuring less than 1.5 cm and early management within 3 months, particularly when utilizing balloon dilatation—findings consistent with our results.

Concurrently, He et al. [10], in line with considerations of stenosis length, proposed a classification system for US with three grades: (1) graft function deterioration and hydronephrosis on ultrasound without an obvious stricture on a pyelogram; (2) focal (< 1 cm) distal ureteral stenosis at the ureteral anastomotic site; and (3) long segment (> 1 cm) distal ureteral stenosis extending to the proximal ureter or pelvis.

Juaneda et al. [11] conducted a study that revealed a correlation between a short time to diagnosis after kidney transplantation (KT) and a previous acute rejection episode, predicting the success of endourological treatment for ureteral strictures. These findings align closely with our own results, where early-onset stenosis (within the first 3 months) was associated with the success of endoscopic management.

At present, the European Association of Urology (EAU) guidelines on Kidney Transplantation (KT) offer recommendations for ureteral stenosis (US) management, taking into account factors such as timing, stricture anatomy (including length and location), patient characteristics, and surgeon preferences [10]. However, the guidelines do not currently address the shape of the stenosis and its potential impact on the success rate of endoscopic treatment for US.

Notably, a study by Gaya et al. [13] in 2023 provides a rationale for considering stenosis shape. The study found that ureteroenteric anastomotic strictures were more likely to be successfully managed endoscopically when the strictures were less than 1 cm (16.8% vs. 4.4%, p < 0.001) and exhibited a duckbill-shaped configuration (16.7% vs. 3.1%, p < 0.001). This aspect of stenosis shape could be a valuable consideration in refining guidelines for optimizing the success of endoscopic management in US cases.