Ureteroscopy vs laparoscopic ureterolithotomy: equal treatments?

In this issue of the BJUI, Torricelli et al. [1] report results from a randomised trial of participants who underwent treatment for large proximal ureteric stones with flexible ureteroscopy (URS) and holmium:yttrium-aluminium-garnet (Ho:YAG) lithotripsy or retroperitoneal laparoscopic ureterolithotomy (RLU). In total, 64 patients were included and randomised. Stone-free rates (SFRs) were 84.3% for URS and 93.7% for RLU (P = 0.23). There were no differences in complication rates, operative time or hospital stay. The authors conclude that both URS and RLU demonstrate high efficiency and low morbidity in the treatment of large proximal ureteric stones.

Since the reporting of the first experiences in the early 1980s, the evolution in URS has been extraordinary. High SFRs and few minor complications have made URS for ureteric stones the preferred treatment option [2]. SFRs of 100% after day-case surgery procedures have been reported in randomised trials using either Ho:YAG or thulium fibre lasers [3, 4]. In special circumstances with large, impacted stones or challenging anatomy, other treatment options may still be an alternative. However, European Association of Urology guidelines state laparoscopic or open stone surgery to be a valid option in complicated cases only when multiple endourological approaches have failed [2].

Torricelli et al. [1] should be commended for performing a randomised trial comparing URS and RLU treating large proximal stones. However, a randomised design alone is no guarantee for scientific quality, and the authors are correct in their suspicion of the study being underpowered. The power analysis made prior to study start returned a sample size of 49 patients in each group to detect a significant difference between the treatment arms. Despite this, only 64 patients were included in total. The authors advocate a lower sample size than calculated pointing out the SFR for RLU may be higher than anticipated. On the other hand, the authors’ assumption of SFR for URS being 75% is probably too low and in contrast to reports in other randomised studies [3, 4]. A higher and more realistic estimate for SFR in the URS group would in fact return a need for an even larger sample size. Lack of patients prevent detection of potential differences between the treatment groups as demonstrated in the present study. It is therefore still not known which treatment is better. On the other hand, given the reported results in the Torricelli et al. study [1], the differences between the two treatments may not be as large as anticipated after all.

Interesting to note, one in three of the patients had persistent hydronephrosis on CT scan at 3 months after surgery, and ureteric stricture was detected in one. The authors suggest longstanding obstruction prior to surgery as an explanation. This might well be true, but the significant number of patients with persistent dilatation may also hide undetected ureteric strictures. In the present study, dynamic scintigraphy was performed to exclude obstruction in these patients. However, the ability to detect significant obstruction on isotopic renography may be unreliable [5]. As impaction of a large ureteric stone is a known risk factor for stricture formation, it may be suggested that all patients with persistent hydronephrosis after treatment are best assessed with a second URS [6].

The Torricelli et al. [1] study represents one of very few randomised trials comparing URS and laparoscopy in the treatment of ureteric stones. However, larger studies are needed to highlight the differences between these treatments. Contrary to the authors’ conclusion that RLU is an appealing alternative to URS for urologists without access to lasers or flexible ureteroscopes, I would rather recommend sending these patients to a referral centre with the required expertise. However, I do agree that retrograde URS remains the preferred choice even for large, impacted stones in the proximal ureter.

Øyvind Ulvik is a consultant for Olympus.