Husmann, Douglas A.

Bladder compliance is defined as bladder’s ability to expand in volume without a significant change in pressure. The bladder wall is a multi-layered structure including a muscular layer and fibrous connective tissue. As the percent of connective tissue in the bladder interstitium increases compared to smooth muscle, the bladder becomes more rigid and less capable of expanding during filling. Currently, urodynamic studies (UDS) are considered as the clinical gold standard for bladder compliance assessment. This procedure is invasive and is associated with patient discomfort and is expensive. Ultrasound bladder vibrometry (UBV) is a novel acoustic-radiation-forced-based method for noninvasive assessment of bladder compliance. In UBV, an impulsive acoustic radiation force is focused on the bladder wall (under B-mode ultrasound image guidance) to induce vibrations which may be modeled by as a Lamb wave. High frame rate ultrasound is then utilized to detect the induced waves. This wave motion is then used to estimate the viscoelastic properties and the compliance of the bladder wall. Our results reveal a remarkable agreement between UBV and UDS cystometry measures, suggesting the potential of UBV as a viable clinical tool for the assessment of bladder compliance.

Objective To describe the extent of use and in‐hospital outcomes of open and laparoscopic pyeloplasty for paediatric pelvi‐ureteric junction ( PUJ ) obstruction in the USA . Patients and Methods Using the 2004–2008 N ationwide I npatient S ample, we identified 4590 paediatric patients (≤18 years old) who underwent open or laparoscopic pyeloplasty for PUJ obstruction at 195 hospitals. Multivariable regression models were used to test the associations between hospital and patient covariates (age, gender, race, primary health insurance), type of admission (emergent vs elective), and hospital characteristics (teaching vs non‐teaching status; rural vs urban location) with complications, length of stay ( LOS ), and total hospitalization costs. Results During the 5‐year study interval, 4426 (96.4%) and 164 (3.6%) paediatric patients diagnosed with PUJ obstruction underwent open and laparoscopic pyeloplasty, respectively. The proportion of patients undergoing laparoscopic pyeloplasty gradually increased from 2.4% in 2004 to 4.4% in 2008, but this increase was not significant ( P = 0.22 for trend). On multivariable analysis, laparoscopic pyeloplasty was observed to have rates of postoperative complications (2.51 vs 5.00; P = 0.67), LOS (2.42 vs 2.75; P = 0.33) and total hospitalization cost ($9755 vs $8537; P = 0.24) similar to those of open pyeloplasty. Conclusions While laparoscopic pyeloplasty was generally an infrequent operation performed for paediatric PUJ obstruction during the period studied, this minimally invasive surgery provided similar outcomes in terms of in‐hospital complications, LOS and total hospitalization costs. The results of this study inform policymakers about the comparative effectiveness of laparoscopic and open pyeloplasty.