title: Percutaneous management of calculi within horseshoe kidneys.
abstract: OBJECTIVE
  Percutaneous treatment of patients with calculi in a horseshoe kidney can be challenging due to the altered anatomical relationship in the retroperitoneum. Therefore, we performed a multi-institutional review to assess the safety and efficacy of this minimally invasive technique.
  
  
  METHODS
  Of 37 patients identified with calculi in a horseshoe kidney at 3 institutions 24 (65%) underwent percutaneous nephrolithotripsy as primary treatment. Average patient age was 48.4 years and 75% of the patients were male. In 3 patients with staghorn calculi mean stone size as measured by computed digitized stone surface area was 448 mm2. Mean followup was 5.8 months. The stone-free rate, complication rate, need for secondary intervention and stone composition were evaluated.
  
  
  RESULTS
  Renal access was obtained through an upper pole calix in 63% of the cases, a lower calix in 25% and a middle calix in 4%. Access location was not documented in 1 patient (4%). Of the 24 patients 21 (87.5%) were rendered stone-free after primary or second look procedures. Flexible nephroscopy was used in 84% of cases. Minor complications occurred in 4 patients (16.7%), whereas 3 (12.5%) experienced major complications, including significant bleeding necessitating early cessation, nephropleural fistula and pneumothorax. No deaths occurred as a result of this treatment choice. Stone analysis was available for 21 cases (87.5%). Calcium stones predominated (87.5%), followed by uric acid (9.5%) and struvite (4.8%).
  
  
  CONCLUSIONS
  Percutaneous treatment of patients with renal calculi in a horseshoe kidney is technically challenging, usually requiring upper pole access and flexible nephroscopy due to the altered anatomical relationships of the fused renal units. The success rate based on stone-free results and a relatively low incidence of major complications suggest that this minimally invasive management option is an effective means of stone management in this complex patient population.
authors.affiliation: Department of Urology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Ganesh V
authors.initials: GV
authors.lastname: Raj
authors.forename: Brian K
authors.initials: BK
authors.lastname: Auge
authors.forename: Alon Z
authors.initials: AZ
authors.lastname: Weizer
authors.forename: John D
authors.initials: JD
authors.lastname: Denstedt
authors.forename: James D
authors.initials: JD
authors.lastname: Watterson
authors.forename: Darren T
authors.initials: DT
authors.lastname: Beiko
authors.forename: Dean G
authors.initials: DG
authors.lastname: Assimos
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Preminger
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007668:Kidney / Q000002:abnormalities*; D007669:Kidney Calculi / Q000737:chemistry / Q000601:surgery*; D008096:Lithotripsy / Q000009:adverse effects / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies