Ureteral stones in children: Are measurements in a longitudinal or transverse plan predictive of stone passage?
Campbell Grant, MD, William R. DeFoor, Jr., MD, MPH, Andrew Angel, BS, Marion Schulte, RN, MHSA, Christopher Anton, MD, Michael Nasser, MD, Thomas Fitzgibbon, MD, Michael Daugherty, MD, Andrew Strine, MD, Brian VanderBrink, MD, Eugene Minevich, MD, Pramod Reddy, MD, Andrew Trout, MD.
Cincinnati Children's Hospital, Cincinnati, OH, USA.
BACKGROUND: The size of an obstructing ureteral stone on imaging is often used to counsel patients on their probability of successful passage. Some studies in adults have shown that the shape of the stone and the difference between longitudinal and transverse lengths can impact stone passage rates. However, no such studies have been reported in children. Additionally, the length of the stone in one plane is often reported without the plane being specified. We sought to evaluate if stone passage rates in children differed based on the plane of imaging.
METHODS: We conducted a retrospective cohort study of children less than 18 years of age presenting to a single institution from 2010 to 2020. Inclusion criteria included an obstructing ureteral stone diagnosed by computed tomography (CT). Patients with bilateral stones and multiple stones in one ureter were excluded. Patients with resolution of symptoms but no follow up imaging or those lost to follow up were also excluded. Images were independently reviewed by two Pediatric Radiologists. Successful stone passage was defined if follow up CT or ultrasound imaging within six weeks confirmed the absence of the stone. Univariate and multivariable logistic regression analysis was performed using MedCalc® Statistical Software.
RESULTS: A total of 123 patients with ureteral stones were identified during the study period. 68 patients met inclusion criteria. Of the excluded patients, 13 were lost to follow-up and 5 had symptom resolution without imaging confirmation. The median age at presentation was 14 years old. 33 were male and 35 were female. 33 stones were located in the proximal or mid-ureter, and 35 were at the ureterovesical junction. The median stone size was 3.5 mm in both transverse and longitudinal dimensions. 76% of patients were started on medical expulsive therapy at the time of presentation. 29 of 68 (43%) patients had spontaneous stone passage within six weeks. 23 of the 39 requiring surgery underwent intervention within 48 hours of presentation. On univariate analysis, stones less than 3.5 mm in both planes were more likely to pass spontaneously. On logistic regression modeling, stone diameter less than 3.5 mm in the transverse axis remained significant with an OR of 6.1 (95% CI 1.4-25, p=0.01). Gender, age, and use of medical expulsive therapy were not significant predictors of stone passage.
CONCLUSIONS: A ureteral stone measuring less than 3.5 mm in the transverse axis has a higher likelihood of passing spontaneously. The transverse length of a stone should be reported on imaging findings if available. This may be a better determinate for counseling patients on their odds of successful stone passage.
Back to 2021 Posters