Visceral adipose tissue loss and 24-hour urinary profile changes post-bariatric surgery.

INTRODUCTION: The relationship between obesity and nephrolithiasis is a well-documented phenomenon. Visceral adipose tissue (VAT) has been proposed to be an accurate indicator of metabolic derangement. We present a study that investigates the relationship between computed tomography (CT) delineated VAT measurements and 24-hour urine (24 HU) profiles in the context of profound weight loss. MATERIALS AND METHODS: A total of 86 patients with a history of nephrolithiasis who underwent bariatric surgery were reviewed. All patients had pre and postoperative 24 HU analysis and CT kidney and urinary bladder performed. CT-based fat delineation program, AnalyzePro, was used to measure VAT at levels L4-L5 (VAT 1) and L1-L2 (VAT2). Univariate and multivariate analysis was utilized to examine associations between VAT measurements and comorbidities, 24 HU values, and postoperative urinary changes. RESULTS: Preoperative VAT2 was correlated with preoperative serum creatinine and all 24 HU (R2: 0.23-0.43, p = < 0.001-0.030). Only VAT1 and VAT2 had relationships with hypertension, dyslipidemia, and metabolic syndrome (R2: 0.25-0.30, p = 0.004-0.015). The percent change in VAT1 and VAT2 was a significant predictor of change in 24 HU uric acid (respectively, R2: 0.14, beta: -0.03, p = 0.002 and R2: 0.13, beta: -0.03, p = 0.003). CONCLUSIONS: This study found VAT to have strong correlations with urinary outcomes in obese patients, especially in the excretion of uric acid. These findings support a potential use of CT delineated measurements of fat as a surrogate measure for urinary metabolites, and may be used as a marker for patient counseling in stone prevention.

A Randomized Comparison of 2 Robotic Virtual Reality Simulators and Evaluation of Trainees' Skills Transfer to a Simulated Robotic Urethrovesical Anastomosis Task.

OBJECTIVE: To determine, via a randomized comparison study, whether robotic simulator-acquired skills transfer to performance of a urethrovesical anastomosis (UVA) on a 3-dimensional-printed bladder model using the da Vinci Robot. MATERIALS AND METHODS: Medical students, surgical residents, and fellows were recruited and divided into 2 groups: Group 1 (G1) (junior trainees) and Group 2 (G2) (senior trainees). Participants were randomized to identical simulator training curricula on the dV-Trainer (dV-T) or da Vinci Surgical Skills Simulator (dVSSS). Participants then completed a UVA task on a 3-dimensional-printed bladder model using the da Vinci robot. Three blinded expert robotic surgeons rated videotaped performances of the UVA task using validated assessment tools, namely, the Global Evaluative Assessment of Robotic Skills (GEARS; overall procedure) and Robotic Anastomosis Competence Evaluation (RACE; specific to UVA). RESULTS: Thirty-nine participants (G1 = 23 and G2 = 16) completed the study. Participants in G2 had significantly more simulation and surgical experience compared with G1 (P <.05). UVA scores of the dVSSS group were higher compared with dV-T (GEARS: P = .09; RACE: P = .01). In the G1 cohort, dVSSS scores were significantly higher than dV-T (GEARS: P = .01; RACE: P <.01). In the G2 cohort, scores were statistically similar (GEARS: P = .32; RACE: P = .91). CONCLUSION: Compared with the dV-T, the dVSSS training led to superior GEARS and RACE scores for performance of the UVA task in junior trainees, but not in senior trainees. The dVSSS can be used to improve surgical skills acquisition in less experienced trainees in a safe and effective manner.

Unilateral Renal Agenesis: Necessity of Postnatal Evaluation in a Contemporary Series.

OBJECTIVE: To assess the need for postnatal evaluation and the long-term consequences in patients with prenatal diagnosis of unilateral renal agenesis (URA). MATERIALS AND METHODS: A retrospective review of the records of all patients with prenatal diagnosis of URA between 2004 and 2013 was done. We included all patients who underwent postnatal evaluation with renal bladder ultrasound (RBUS), dimercaptosuccinic acid scan, and a voiding cystourethrogram. Long-term follow-up included physical examination and assessment of contralateral renal growth. RESULTS: A total of 46 children (24 boys and 22 girls) with URA were identified. Ultrasounds showed associated hydronephrosis in 9 patients (19%). Dimercaptosuccinic acid scans confirmed the diagnosis of URA in all patients and showed renal scars in 2 solitary kidneys (4%). Vesicoureteral reflux was diagnosed in 4 patients (12%); all were of low grade and managed conservatively. After a mean follow up of 4 years, RBUS showed compensatory hypertrophy in 31 patients (67%), 3 patients (6%) developed chronic kidney disease, and 2 patients (4%) developed hypertension. CONCLUSION: Prenatally detected cases of URA should be promptly evaluated. RBUS is found to be sufficient for diagnosis. However, additional imaging may be indicated for confirming the diagnosis and detection of other associated urinary anomalies. Serial assessment of the contralateral solitary kidney growth and serum creatinine measurement will be helpful to assess kidney function on the long term.