Authors: Johannes Huber Ingmar Wegner HansPeter Meinzer Peter Hallscheidt Boris Hadaschik Sascha Pahernik Markus Hohenfellner
Publish Date: 2010/09/11
Volume: 25, Issue: 4, Pages: 1307-1312
Abstract
Navigation systems are promising tools for improving efficacy and safety in surgical endoscopy and other minimally invasive techniques The aim of the current study is to investigate electromagnetic tracking EMT for navigated renal access in a porcine modelFor our proofofprinciple study we modified a recently established porcine ex vivo model Via a ureteral catheter which was placed into the desired puncture site a small sensor was introduced and located by EMT Then a tracked needle was navigated into the collecting system in a “rendezvous” approach A total of 90 renal tracts were obtained in six kidneys using EMT with a maximum of three punctures allowed per intervention For each puncture number of attempts to success final distance to probe puncture time and localization were assessed We compared absolute and relative frequencies using the chisquare test and applied the Mann–Whitney Utest for continuous variablesNo major problems were encountered performing the experiment Access to the collecting system was successfully obtained after a single puncture in 91 82/90 and within a second attempt in the remaining 9 8/90 Thus a 100 success rate was reached after a maximum of two punctures Location of the calyx did not have a significant effect on success rate p = 0637 After a learning phase of 30 punctures higher success rate 96 versus 83 p = 0041 was accomplished within shorter puncture time 14 versus 17 s p = 0049 and with higher precision 17 versus 28 mm p 0001With respect to other established techniques use of EMT seems to decrease the number of attempts and procedural time remarkably This might contribute to greater safety and efficacy when applied clinically The presented approach appears to be promising especially in difficult settings provided that in vivo data support these initial results
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