WCE 2017: In Patients with Obstructing Uteral Calculi, the Severity of Perinephric Stranding is Predictive of Creatinine Elevation

Vancouver, Canada (UroToday.com) Papagiannopoulos et al. present a retrospective single-institution study of 148 patients identified by reviewing their institution’s radiology dictation system for non-contrast CT (NCCT) scan reports with the words “ureteral stone.” NCCT scans were done on patients presenting to the emergency room and were read by a single radiologist who coded variables for stone size, stone location, and degree of perinephric fat stranding.

The mean stone size was 4.8 ± 3.0 mm. Stone location was distal in 85 patients (57%) and proximal in 63 patients (43%). Both the degree of hydronephrosis and the degree of perinephric fat stranding were predominantly mild. Severe hydronephrosis was noted in only three patients (2%). Severe perinephric fat stranding was noted in 14 patients (10%). Seventeen patients (22%) had a positive urine culture. Forty-eight patients (32%) were admitted for reasons including pain, infection, stone size, acute kidney injury, and anemia. 

The degree of perinephric fat stranding was not associated with stone location, degree of hydronephrosis, or urine culture results (p > 0.05). 

These authors are to be commended for such a creative use of their institution’s radiology dictation system, as well as for demonstrating the benefits of interdisciplinary collaboration. However, there are concerns about their statistical analysis. The authors state that patients with moderate-severe perinephric stranding had three-fold greater odds of elevated creatinine from baseline, when compared to those with absent or mild stranding. Was creatinine modeled here as a categorical or continuous variable? In addition, what other variables were included in the multivariate model? 

Presenter: Dimitri Papagiannopoulos, MD

Authors: Dimitri Papagiannopoulos, MD, John Ebersole, M. Ryan Farrell, MD, MPH, Gregory White, and Leslie A. Deane, MB.BS, MS, FRCSC, FACS
Affiliation: Department of Urology University of California San Diego, San Diego, California, Department of Radiology, Department of Urology, Rush University Medical Center, Chicago, IL, USA

Written by: Michael Owyong (@ohyoungmike), LIFT Fellow, Department of Urology, UC Irvine Medical Center, Orange, CA, USA at 35th World Congress of Endourology– September 12-16, 2017, Vancouver, Canada.