title: What happens to asymptomatic lower pole kidney stones smaller than 10 mm in children during watchful waiting?
abstract: The optimal management of lower pole kidney (LPK) stones in children is controversial. The aim of this study was to determine the outcomes of children with asymptomatic isolated LPK stones smaller than 10 mm during follow-up.
  
  
  
  A total of 242 patients with 284 stones presenting at our institution between June 2004 and December 2014 with an asymptomatic, single LPK stone with a diameter of <10 mm were enrolled in the study. All children were assigned to receive first-line therapy and then categorized according to the need for medical intervention. Age, gender, stone laterality, stone size and type, associated urinary tract problems, and uncontrolled metabolic status were assessed as predictive factors of medical treatment for small (<10 mm) asymptomatic LPK stones. Stone-free rates were compared between interventions.
  
  
  
  The mean age and mean stone size were 9.4 ± 1.9 years and 7.4 ± 0.6 mm at admission, respectively. Stone progression rate was 61.2%, and the mean time for intervention was 19.2 ± 4.6 months. Flexible ureterorenoscopy (n = 68) or micro-percutaneous nephrolithotomy (n = 4) were performed for 72 stones (25.4%; group 1), and extracorporeal shock wave lithotripsy was performed for 102 stones (35.9%; group 2). The stone-free rates were 81.8 and 79.3% in group 1 and 2, respectively (p > 0.05). The remaining asymptomatic stones (110, 38.8%; group 3) were managed by continued observation, and at the end of the observation time (mean 40.8 ± 20.8 months) the spontaneous passage rate was 9.1% in this group. In the multivariate analysis, stone size of >7 mm, concurrent renal anomalies, and stones composed of magnesium ammonium phosphate (struvite) and cystine were statistically significant predictors of the need for intervention.
  
  
  
  Children with stones larger than 7 mm, renal anomalies, or stones composed of metabolically active cystine or struvite are more likely to require intervention, and those with asymptomatic LPK stones smaller than 10 mm can be managed by continued observation.
authors.affiliation: Department of Pediatric Urology, School of Medicine, Ankara University, Sihhiye, Ankara, 06100, Turkey. onurtelli@yahoo.com.
authors.forename: Onur
authors.identifier: 0000-0002-7454-7661
authors.initials: O
authors.lastname: Telli
authors.affiliation: Department of Urology, School of Medicine, Ankara University, Ankara, Turkey.
authors.forename: Nurullah
authors.initials: N
authors.lastname: Hamidi
authors.affiliation: Department of Urology, School of Medicine, Ankara University, Ankara, Turkey.
authors.forename: Uygar
authors.initials: U
authors.lastname: Bagci
authors.affiliation: Urology Clinic, Ankara Training and Research Hospital, Ankara, Turkey.
authors.forename: Arif
authors.initials: A
authors.lastname: Demirbas
authors.affiliation: Urology Clinic, Ankara Training and Research Hospital, Ankara, Turkey.
authors.forename: Ahmet Metin
authors.initials: AM
authors.lastname: Hascicek
authors.affiliation: Department of Pediatric Urology, School of Medicine, Ankara University, Sihhiye, Ankara, 06100, Turkey.
authors.forename: Tarkan
authors.initials: T
authors.lastname: Soygur
authors.affiliation: Department of Pediatric Urology, School of Medicine, Ankara University, Sihhiye, Ankara, 06100, Turkey.
authors.forename: Berk
authors.initials: B
authors.lastname: Burgu
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003553:Cystine / Q000737:chemistry; D005260:Female; D006801:Humans; D007223:Infant; D007669:Kidney Calculi / Q000737:chemistry / Q000473:pathology* / Q000628:therapy*; D008096:Lithotripsy; D008297:Male; D000074642:Nephrolithotomy, Percutaneous; D012737:Sex Factors; D000069877:Struvite / Q000737:chemistry; D016896:Treatment Outcome; D014570:Urologic Diseases / Q000150:complications; D057832:Watchful Waiting
chemical_list: D003553:Cystine; D000069877:Struvite
keywords: Asymptomatic; Children; Kidney; Kidney stones; Lower pole kidney stone