[Interrater reliability and clinical impact of the Post-Ureteroscopic Lesion Scale (PULS) grading system for ureteral lesions after ureteroscopy : Results of the German prospective multicenter BUSTER project]

Abstract

Background: The Post-ureteroscopic Lesion Scale (PULS) was designed as a standardized classification system for ureteral lesions after uretero(reno)scopy (URS). This study evaluates its routine use and a possible clinical impact based on a representative patient cohort.

Materials and methods: Data of 307 patients in 14 German centers within the BUSTER project were used to test 3 hypotheses (H): PULS score shows a high interrater reliability (IRR) after independent assessment by urologic surgeon and assistance personnel (H1); PULS score is correlated with the frequency of postoperative complications during hospital stay (H2); post-URS stenting of the ureter is associated with higher PULS scores (H3).

Results: Median age of patients was 54.4 years (interquartile range [IQR] 44.4-65.8; 65.5% male). Median diameter of index stones was 6 mm (IQR 4-8) with 117 (38.4%) pyelo-caliceal and 188 (61.6%) ureteral stones. Overall, 70 and 82.4% of patients had pre-stenting and post-URS stenting, respectively. Stone-free status was achieved in 68.7% after one URS procedure with a complication rate of 10.8% (mostly grade 1-2 according to Clavien-Dindo). PULS scores 0, 1, 2 and 3 were assessed in 40%, 52.1%, 6.9% and 1% of patients, respectively, when estimated by urologic surgeons. PULS score showed a high IRR between the urologic surgeon and assistance personnel (κ = 0.883, p < 0.001), but was not significantly correlated with complications (ρ = 0.09, p = 0.881). In contrast, a significant positive correlation was found between PULS score and post-URS stenting (ρ = 0.287, p < 0.001). A PULS score of 1 multiplied the likelihood of post-URS stenting by 3.24 (95% confidence interval 1.43-7.34; p = 0.005) as opposed to PULS score 0.

Conclusions: Removal of upper urinary tract stones using URS is safe and efficacious. Real-world data provided by this study confirm a high IRR of the PULS score and its clinical impact on the indication for post-URS stenting. A future prospective randomized trial should evaluate a possible standardization of post-URS stenting based on PULS score assessment.

Keywords: Complications; Interobserver; Stents; Stone, urinary tract; Stone-free rate.