We have shown that a simple algorithm, based on time-frequency analysis of bladder pressure, may be a promising tool in the clinical setting. The algorithm can provide quantitative data on non-voiding bladder activity in patients and quantify the changes according to phenotype. Moreover the algorithm can detect DO, showing potential for triggering conditional bladder stimulation.

Purpose This study aimed at evaluating whether removal of the ureteral stent the day before scheduled secondary intervention facilitates spontaneous ureteral stone passage and thus can spare the pre-stented patient this surgery. Methods Retrospective analysis of a single-centre consecutive series of 216 patients after previous stenting due to a symptomatic ureteral stone from 01/2013 to 01/2018. Indwelling stents were removed under local anaesthesia. Patients were told to filter their urine overnight. Multivariate analysis was performed to assess predictive factors for spontaneous stone passage. Results 34% (74/216) of patients had spontaneous stone passage while the stent was indwelling. Of the remaining 142 patients, 41% (58/142) had spontaneous stone passage within 24 h after stent removal. Only 84/216 (39%) patients needed secondary intervention. Multivariate logistic regression analysis of all 216 patients showed a significant association between spontaneous stone passage and smaller stone size (p < 0.001), distal stone location (p = 0.046) and stent dwell time (p = 0.02). Predictive factors for spontaneous stone passage after stent removal were smaller size (p < 0.001), distal location (p = 0.001), and stone movement while the stent was indwelling (p = 0.016). A treatment strategy was established that helps select patients suitable for conservative management. Conclusions The majority (61%) of ureteral stones passed spontaneously after pre-stenting; 34% while the stent was indwelling, 27% within 24 h after stent removal. Besides distal stone location, stone size (< 6 mm) and stone movement (≥ 5 cm) while the stent is indwelling indicate patients who are likely to pass their ureteral stone spontaneously after stent removal. The treatment strategy (decision tree) presented here helps identify those patients. Trial registration https ://doi.org/10.1186/ISRCT N1211 2914. KeywordsDouble J • Pre-stenting • Spontaneous stone passage • Ureteral stone • Urolithiasis * Beat Roth