Category: Clinical Stones: Outcomes

MP13-16 - Spontaneous stone passage: crystalline composition predicts stone size

Fri, Sep 21
2:00 PM - 4:00 PM

Introduction & Objective : Sparse data regarding spontaneous stone passage establish current recommendations based on stone size. The present study evaluated whether size of spontaneously passed stones (SPS) may vary according to their major crystalline constituent.

Methods : A search for SPS was conducted in a large database that was built over the last 33 years at the Necker Hospital (1985 – 2010) and at our institution (2010 – 2018) in Paris. Eligible major constituents were: calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD), anhydrous uric acid (UA0), dehydrated uric acid (UA2) carbapatite (CA), brushite (BRU), struvite (STR) and cystine (CYS). Cases with documented stenotic urinary tract disease or with past history of anastomotic urinary tract surgery were excluded. Stone volume was calculated by the formula of an ellipsoid: 4/3*π*a*b*c, where a, b and c correspond to maximal stone radii in three dimensions, respectively. Continuous data were compared using one-way ANOVA. Proportions were compared by Chi-square test. Logistic regression analysis was performed to identify predictors of maximal stone diameter ≥6 mm.

Results : A total of 17983 SPS originating from 13498 males and 4485 females were eligible for analysis. Mean age was 46 years (range 18 – 100). Mean maximal diameter and mean volume significantly differed between major constituent groups (p3, 95%CI 17-18) and largest for STR (7.4 mm, 95%CI 6.3-8.4; 131 mm3, 95%CI 87-175). Only 6% of COM stones had maximal diameter ≥6 mm, whereas more than one quarter of BRU, STR and CYS stones were above this cutoff (31%, 59% and 35%, respectively; p<0.001). In a model adjusting for sexes and age, crystalline composition revealed as an independent predictor for maximal diameter ≥6 mm (p<0.001; Table 1).

Conclusions : Size of SPS significantly differs depending on their crystalline composition. This may impact on size-related treatment recommendations whenever stone composition can be predicted from past history.

Etienne X. Keller

Fellow of the ES
Sorbonne Université, GRC n°20, Groupe de Recherche Clinique sur la Lithiase Urinaire, AP-HP, Hôpital Tenon, F-75020 Paris, France
Paris, Ile-de-France, France

Vincent De Coninck

AZ Klina
Brasschaat, Antwerpen, Belgium

Vincent De Coninck graduated as a medical doctor from the Free University of Brussels, Belgium (VUB) in 2011. He became a certified urologist in 2017 after a training at the University Hospital of Brussels (Prof. Dr. Dirk Michielsen) and OLV Aalst (Prof. Dr. Alex Mottrie), where he developed a special interest in the minimal invasive treatment of benign and malignant pathologies. In the same year, he became Fellow of the European Board of Urology.
In 2018, he completed a one-year fellowship program of the Endourological Society in Paris, France under the supervision of Prof. Dr. Olivier Traxer. During that fellowship, he also obtained a diploma in urolithiasis, organized by Dr. Michel Daudon at the Sorbonne University in Paris, France. Afterwards, he was trained in HoLEP by Dr. Karin Lehrich in Berlin, Germany.
Currently, he is completing a three-month fellowship under the supervision of Dr. Guido Giusti in Milan, Italy. In December 2018, he will start working as an endourologist in AZ Klina, Brasschaat, Belgium. He will focus on the medical and surgical treatment of kidney stones and benign prostatic obstruction (HoLEP) and he will continue publishing articles relating to the management of patients with renal stone disease.

Steeve S. Doizi

Sorbonne Université, GRC n°20, Groupe de Recherche Clinique sur la Lithiase Urinaire, AP-HP, Hôpital Tenon, F-75020 Paris, France
Paris, Ile-de-France, France

Michel Daudon

CRISTAL Laboratory, Laboratoire des Lithiases, Service des Explorations Fonctionnelles Multidisciplinaires, INSERM, UMRS 1155 UPMC, Tenon Hospital, Paris, France
Paris, Ile-de-France, France

Olivier O. Traxer

Sorbonne Universite, GRC n020 Lithiase Renale, AP-HP, Hospital Tenon, F-75020 Paris, France
Paris, Ile-de-France, France