Determining the angle and depth of puncture for fluoroscopy-guided percutaneous renal access in the prone position

Abstract

Introduction:Optimal renal access is necessary for ensuring a successful and complication-free percutaneous nephrolithotomy. We describe a technique to determine the angle and depth of puncture for fluoroscopy-guided percutaneous renal access in the prone position.Materials and Methods:Forty-two consecutive patients undergoing percutaneous nephrolithotomy from January 2014 had a fluoroscopy-guided access in the prone position. Using the bull's eye technique, the site of skin puncture and the angle of puncture were determined. These parameters were utilized to calculate, mathematically, the depth of the targeted calyx. These measurements were then utilized for puncture. The actual depth of puncture was then calculated. The number of attempts, time of fluoroscopy and difference between estimated and actual depth were noted and analyzed.Results and Limitations:There was a difference of 0-3 mm between the estimated and the actual depth at which puncture was made. Single-attempt puncture was possible in >95% cases. No complications related to access were observed.Conclusion:By estimating the angle and depth of puncture, the percutaneous renal access becomes technically less challenging.

Trigonometric Concept of Fluoroscopy-Guided Percutaneous Renal Access

“…Gyanendra et al describe a method of determining the angle and depth of puncture using the universal triangle solver software. However, this requires the bull’s eye technique to assess the angle of calyx and a smartphone to perform the calculations [ 11 ].…”

Techniques for fluoroscopy-guided percutaneous renal access: An analytical review

“…Now, whether the puncture is made at the point B or is from point B1, the same angle of the needle is determined using a protractor and the trajectory of the needle is defined. [32] Care should be taken that all measurements are taken in the same phase of respiration, usually end expiration. Often, it is difficult to maintain the angle of needle and look at the angle on the protractor.…”

Prone percutaneous nephrolithotomy: its advantages and our technique for puncture

“…Recently, Sharma et al ( 16 ) proposed a new technique, in which although some triangulation is used, they manage to mark on the skin the exact point where the target calyx is visualized under the C-arm at 0° and at 30°. They use these marks to calculate the deepness of the calyx and the needle inclination required for puncture.…”