Systematic evaluation of a holmium:yttrium-aluminum-garnet laser lithotripsy device with variable pulse peak power and pulse duration

AbstractObjectiveThe Holmium:yttrium-aluminum-garnet (Ho:YAG) laser is the standard lithotrite for ureteroscopy. This paper is to evaluate a Ho:YAG laser with a novel effect function in vitro, which allows a real-time variation of pulse duration and pulse peak power.MethodsTwo types of phantom calculi with four degrees of hardness were made for fragmentation and retropulsion experiments. Fragmentation was analysed at 5 (0.5 J/10 Hz), 10 (1 J/10 Hz), and 20 (2 J/10 Hz) W in non-floating phantom calculi, retropulsion in an ureteral model at 10 (1 J/10 Hz) and 20 (2 J/10 Hz) W using floating phantom calculi. The effect function was set to 25%, 50%, 75%, and 100% of the maximum possible effect function at each power setting. Primary outcomes: fragmentation (mm3), the distance of retropulsion (cm); ≥5 measurements for each trial.ResultsAn increase of the effect feature (25% vs. 100%), i.e., an increase of pulse peak power and decrease of pulse duration, improved Ho:YAG laser fragmentation. This effect was remarkable in soft stone composition, while there was a trend for improved fragmentation with an increase of the effect feature in hard stone composition. Retropulsion increased with increasing effect function, independently of stone composition. The major limitations of the study are the use of artificial stones and the in vitro setup.ConclusionChanges in pulse duration and pulse peak power may lead to improved stone fragmentation, most prominently in soft stones, but also lead to increased retropulsion. This new effect function may enhance Ho:YAG laser fragmentation when maximum power output is limited or retropulsion is excluded

Circulating cell-free DNA assessment in biofluids from children with neuroblastoma demonstrates feasibility and potential for minimally invasive molecular diagnostics

Liquid biopsy strategies in pediatric patients are challenging due to low body weight. This study investigated cfDNA size distribution and concentration in blood, bone marrow, cerebrospinal fluid, and urine from 84 patients with neuroblastoma classified as low (n = 28), intermediate (n = 6), or high risk (n = 50) to provide key data for liquid biopsy biobanking strategies. The average volume of blood and bone marrow plasma provided ranged between 1 and 2 mL. Analysis of 637 DNA electropherograms obtained by Agilent TapeStation measurement revealed five different major profiles and characteristic DNA size distribution patterns for each of the biofluids. The proportion of samples containing primarily cfDNA was, at 85.5%, the highest for blood plasma. The median cfDNA concentration amounted to 6.28 ng/mL (blood plasma), 58.2 ng/mL (bone marrow plasma), 0.08 ng/mL (cerebrospinal fluid), and 0.49 ng/mL (urine) in samples. Meta-analysis of the dataset demonstrated that multiple cfDNA-based assays employing the same biofluid sample optimally require sampling volumes of 1 mL for blood and bone marrow plasma, 2 mL for cerebrospinal fluid, and as large as possible for urine samples. A favorable response to treatment was associated with a rapid decrease in blood-based cfDNA concentration in patients with high-risk neuroblastoma. Blood-based cfDNA concentration was not sufficient as a single parameter to indicate high-risk disease recurrence. We provide proof of concept that monitoring neuroblastoma-specific markers in very small blood volumes from infants is feasible

The Real Daily Need for Incontinence Aids and Appliances in Patients with Neurogenic Bladder Dysfunction in a Community Setting in Germany

PURPOSE: For successful long-term rehabilitation of patients with neurogenic lower urinary tract dysfunction (NLUTD), it is necessary to define the objective requirement for urological aids based on a scientifically validated basis. METHODS: This was a cross-sectional multicenter study, based on a questionnaire. Data concerning bladder management and daily consumption of urological appliances for patients with NLUTD in a community setting were collected through a standardized survey. RESULTS: Seven hundred and sixty-seven records were analyzed: 543 males, 221 females (N/A = 3). Patients using intermittent catheterization (n= 608) required 5.06 (mean) single-use catheters per day. Out of them, 94 (15.5%) required additional pads (mean: 2.29 per day), 34 patients (5.6%) additionally used pants (mean: 2.55 per day) and 46 patients (7.6%) utilized condom catheters (mean: 3.81 per day) between catheterizations. Among all, 126 patients (16.4%) used pads (mean: 5.03 per day), and 51 patients (6.6%) used pants (mean: 3.03 per day). Women needed both pads (p < 0.0001) and diapers (p = 0.0084) significantly more frequently than men. Eighty-two of the male patients (15.1%) applied condom catheters (mean: 2.8 per day). The target value of the objective daily requirement of incontinence aids for adult patients with NLUTD (based on the upper twofold standard deviation from the mean value) was defined as follows: up to nine single-use catheters, seven condom catheters, nine pads and/or seven pants. A “mixed supply” of different incontinence aids is part of the daily supply for many patients. CONCLUSION: For the first time, these results allow a reasonable regulation of urological aids and appliances based on scientific data for patients with neurogenic bladder