title: Laser-guided percutaneous kidney access with the Uro Dyna-CT: first experience of three-dimensional puncture planning with an ex vivo model.
abstract: OBJECTIVE
  Safe and successful puncture of the kidney's collecting system is essential for acute therapy of hydronephrosis or as part of percutaneous nephrolithotomy. The procedure is technically challenging and might lead to major complications. We describe the feasibility of a laser guidance system and three-dimensional puncture planning in the endourological operation room.
  
  
  METHODS
  An Uro Dyna-CT of the biological model was performed with the Artis Zee(®) Ceiling (Siemens Medical Solutions, Erlangen, Germany) to gain multiplanar reconstructions. 10 punctures were performed with the syngo iGuide(®) laser guidance system. Puncture success was depicted with antegrade contrast filling of the collecting system and fluoroscopic control. Puncture time, tract length, and fluoroscopy time was documented.
  
  
  RESULTS
  Data acquisition (8 s) and 3D rendering (48 s) was possible in approximately 1 min. Median time for planning the punctures was 7 [5-15] min. Median puncture time was 4.6 [2-10.2] min. Median tract length was 4.96 [4.33-6.5] cm. Median fluoroscopy time was 0.4 [0.2-1] min. 9 of 10 punctures were successful. A second puncture was needed to gain access to the collecting system in one case, and one puncture was broken up.
  
  
  CONCLUSIONS
  The tested laser guidance system was feasible to perform successful percutaneous punctures of the kidney in this ex vivo study. Handling was intuitive and time within acceptable limits. Due to the requirement of multiplanar reconstructions with higher radiation exposure to the patient than with standard fluoroscopy, this technique should be limited to complex cases.
authors.affiliation: Department of Urology, Medical Centre Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany, manuel.ritter@umm.de.
authors.forename: M
authors.initials: M
authors.lastname: Ritter
authors.forename: M-C
authors.initials: MC
authors.lastname: Rassweiler
authors.forename: A
authors.initials: A
authors.lastname: Häcker
authors.forename: M S
authors.initials: MS
authors.lastname: Michel
mesh_terms: D000818:Animals; D002645:Chickens; D005240:Feasibility Studies; D005471:Fluoroscopy / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007668:Kidney / Q000601:surgery*; D007834:Lasers; D023421:Models, Animal; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D011677:Punctures / Q000379:methods; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000379:methods*