Outcome groups and a practical tool to predict success of shock wave lithotripsy in daily clinical routine.

PURPOSE: To improve outcome prediction of extracorporeal shock wave lithotripsy (SWL) by development of a model based on easily available clinical and radiographical predictors and suitable for daily clinical use. MATERIALS AND METHODS: We evaluated predictive factors for SWL success in 517 consecutive patients suffering from urinary calculi who underwent SWL between 2010 and 2018. Analyses included descriptive statistics, receiver operating characteristic statistics and logistic regression. Predictive value was improved by combining parameters using model selection and recursive partitioning. RESULTS: Of the 517 patients, 310 (60.0%) had a successful SWL. Best individual predictor of SWL success was mean attenuation (MAV), with an area under the curve (AUC) of 0.668, and an optimal cutpoint (OC) of 987.5 HU. The best multivariable model, including MAV, stone size, skin to stone distance (SSD), presence of an indwelling stent, and four interaction effects, yielded an AUC of 0.736. Recursive partitioning would categorize patients into three outcome groups with high (76.9%), intermediate (41%) and low (10%) success probability. High probability of SWL success (76.9%) was found for patients with a stone with MAV ≤ 987 HU or with MAV > 987 HU but stone size ≤ 11 mm and SSD (45°) ≤ 88 mm. CONCLUSION: A model based on four established predictors, and provided as an Excel®-Tool, can clearly improve prediction of SWL success. In addition, patients can be classified into three defined outcome groups based on simple cutpoint combinations. Both tools improve informed decision-making in daily clinical practice and might reduce failure rates.

Transurethral resection of bladder cancer on the lateral bladder wall without obturator nerve block: extent of adductor spasms using the monopolar versus bipolar technique-a prospective randomised study.

PURPOSE: To establish whether bipolar transurethral resection of tumours (bTURB) on the lateral bladder wall is superior to monopolar transurethral resection (mTURB) of such tumours. To our knowledge, this is the first prospective randomised study, which defines complete resection depending on obturator jerk as primary endpoint. METHODS: In a prospective, randomised, single centre study, 52 patients with newly diagnosed or recurrent bladder tumour on the lateral bladder wall were enrolled and randomised to undergo mTURB or bTURB; 44 patients were eligible for analysis, of whom 21 underwent mTURB and 23 bTURB. Any differences between the two techniques related to the incidence of unwanted stimulation of the obturator nerve and subsequent adductor spasms were evaluated. All procedures were carried out under laryngeal mask anaesthesia without obturator nerve block (ONB) and without drug-induced relaxation. RESULTS: Baseline characteristics of the two study groups did not differ statistically significantly. The success rate defined as complete resection of the bladder tumour without any clinically relevant adductor spasm was 61.9% in the monopolar group and 82.6% in the bipolar group (p = 0.18). CONCLUSIONS: Complete, undisturbed resection of tumours of the lateral bladder wall is feasible with mTURB and bTURB. Adductor spasms due to obturator jerk can occur suddenly with the risk of bladder perforation. We therefore support ONB when using spinal anaesthesia and drug-induced relaxation when using general anaesthesia when performing TURB on the lateral bladder wall.

Advanced non-contrasted computed tomography post-processing by CT-Calculometry (CT-CM) outperforms established predictors for the outcome of shock wave lithotripsy.

OBJECTIVES: To evaluate the predictive value of advanced non-contrasted computed tomography (NCCT) post-processing using novel CT-calculometry (CT-CM) parameters compared to established predictors of success of shock wave lithotripsy (SWL) for urinary calculi. MATERIALS AND METHODS: NCCT post-processing was retrospectively performed in 312 patients suffering from upper tract urinary calculi who were treated by SWL. Established predictors such as skin to stone distance, body mass index, stone diameter or mean stone attenuation values were assessed. Precise stone size and shape metrics, 3-D greyscale measurements and homogeneity parameters such as skewness and kurtosis, were analysed using CT-CM. Predictive values for SWL outcome were analysed using logistic regression and receiver operating characteristics (ROC) statistics. RESULTS: Overall success rate (stone disintegration and no re-intervention needed) of SWL was 59% (184 patients). CT-CM metrics mainly outperformed established predictors. According to ROC analyses, stone volume and surface area performed better than established stone diameter, mean 3D attenuation value was a stronger predictor than established mean attenuation value, and parameters skewness and kurtosis performed better than recently emerged variation coefficient of stone density. Moreover, prediction of SWL outcome with 80% probability to be correct would be possible in a clearly higher number of patients (up to fivefold) using CT-CM-derived parameters. CONCLUSIONS: Advanced NCCT post-processing by CT-CM provides novel parameters that seem to outperform established predictors of SWL response. Implementation of these parameters into clinical routine might reduce SWL failure rates.