Renal Calyceal Anatomy Characterization with 3-Dimensional In Vivo Computerized Tomography Imaging

Abstract

Abbreviations and Acronyms 3DPurpose: Calyceal selection for percutaneous renal access is critical for safe, effective performance of percutaneous nephrolithotomy. Available anatomical evidence is contradictory and incomplete. We present detailed renal calyceal anatomy obtained from in vivo 3-dimentional computerized tomography renderings. Materials and Methods: A total of 60 computerized tomography urograms were randomly selected. The renal collecting system was isolated and 3-dimensional renderings were constructed. The primary plane of each calyceal group of 100 kidneys was determined. A coronal maximum intensity projection was used for simulated percutaneous access. The most inferior calyx was designated calyx 1. Moving superiorly, the subsequent calyces were designated calyx 2 and, when present, calyx 3. The surface rendering was rotated to assess the primary plane of the calyceal group and the orientation of the select calyx. Results: The primary plane of the upper pole calyceal group was mediolateral in 95% of kidneys and the primary plane of the lower pole calyceal group was anteroposterior in 95%. Calyx 2 was chosen in 90 of 97 simulations and it was appropriate in 92%. Calyx 3 was chosen in 7 simulations but it was appropriate in only 57%. Calyx 1 was not selected in any simulation and it was anteriorly oriented in 75% of kidneys. Conclusions: Appropriate lower pole calyceal access can be reliably accomplished with an understanding of the anatomical relationship between individual calyceal orientation and the primary plane of the calyceal group. Calyx 2 is most often appropriate for accessing the anteroposterior primary plane of the lower pole. Calyx 1 is most commonly oriented anterior.

Collecting System Percutaneous Access Using Real-Time Tracking Sensors: First Pig Model In Vivo Experience

“…Although surgeon's preferences determine the imaging method choice, fluoroscopy and ultrasounds are the most common imaging technologies for puncture guidance and planning 2,21 . X-ray exposure, 2D image, difficult visualization of small calculi, operator dependence and requirement of skill has been reported as the main limitations associated with these imaging techniques 2,7,8,22 .…”

“…Today, percutaneous nephrolithotomy (PCNL) is the established treatment for staghorn kidney stone removal and usually comprises three main steps: a) insertion of a ureteral catheter to perform a retrograde study; b) puncture of the kidney to establish a percutaneous path; and, c) disintegration with removal of stone fragments [2][3][4][5][6] . The puncture step remains the most challenging task for surgeons, since treatment outcomes are highly dependent on the accuracy of needle puncture in the desired calix 2,7,8 .…”

“…An inaccurate needle puncture can cause some complications such as injuries in the kidney and contiguous organs, difficulty in handling surgical instruments and eventually, prejudice the overall surgical procedure and patient outcome 8 .…”

Kidney Targeting and Puncturing During Percutaneous Nephrolithotomy: Recent Advances and Future Perspectives

“…10,13 CT, however, is the method of choice for the diagnosis and preoperative planning of PCNL, because it has a number of advantages over IVU-namely the detection of renal calculi with a sensitivity and specificity of 97% and 100%, respectively, identification of renal lesions and blood vessels, and three-dimensional (3D) visualization of the urinary system and surrounding structures. 10,13,[24][25][26] On the other hand, CT can also be used with radiopaque contrast dye (angiographic CT) to produce detailed images of blood vessels, ureters, kidney calices, and surrounding tissues. 10 Imaging without X-ray.…”

“…Because patient reposition increases surgery time of about 30 to 40 minutes, however, some practitioners opt to perform the entire procedure with the patient in the supine position. 25,45 The prone position in PCNL is frequently associated with patient discomfort, especially for those with severe musculoskeletal deformities, cardiovascular and respiratory problems. 11 Despite its shortcomings, the prone position facilitates the puncture stage by avoiding abdominal visceral injuries and allowing posterior access to the collecting system, with no limits for instrument excursion and multiple accesses.…”