A +20% adjustment in the CT measured ureteral length is an accurate predictor of true ureteral length prior to ureteral stent placement - Abstract

Purpose: Correct length of ureteral stent is important in minimizing post-placement discomfort and stent migration.

We describe and validate a method to accurately measure ureteral length.

Materials and Methods: Ureteral length in 48 patients undergoing ureteral stent placement for urolithiasis was measured by CT (total thickness of axial slices between UPJ and UVJ) and adjusted up by 20%. The adjusted CT Measurement of Ureteral length was compared with direct intraoperative measurement using Scatter plot and Pearson Correlation coefficient. Correlation coefficients were also calculated between intra-operative ureteral length and various body habitus measurements such as height, weight and waist circumference.

Results: Median patient age was 62 years. Median stone diameter was 7.5mm (1-20). The ratio of left to right sided stones was 2:1. Stone location was in the proximal ureter in 45.8%, distal ureter in 37.5%, kidney in 10.4% and mid ureter in 6.3%. Symptom included adnominal/flank pain (93.8%) followed by nausea/vomiting (39.6%) and gross hematuria (16.7%). Median creatinine was 1.4 (0.8-3.6 mg/dl) and median WBC was 8.6 (2.8-17.6). Median ureteral length was 25.8cm (19.2-29.4) on CT scan and 25.5cm (19.0-29.0) on intra-operative measurement (p=0.57). The Pearson correlation coefficient between the two measurements was 0.979. In contrast, height, weight and waist circumference correlated poorly with intra-operative ureteral length measurements (r = 0.34, 0.19 & 0.40, respectively).

Conclusion: CT-measured ureteral length adjusted up by 20% is a reliable method to accurately measure true ureteral length. This method is superior to traditional indirect methods that rely on body habitus measurements.

Written by:
Shrewsberry AB, Al-Qassab UA, Goodman M, Petros J, Ritenour CW, Issa MM.   Are you the author?
Atlanta Veterans Affairs Medical Center, Urology (112), 1670 Clairmont Road, NE, Decatur, Georgia, United States. Emory University School of Medicine, Department of Urology, Atlanta, Georgia, United States.

Reference: J Endourol. 2013 Mar 28. Epub ahead of print.
doi: 10.1089/end.2013.0041

PubMed Abstract
PMID: 23537290

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