Craniocaudal bull's eye technique for superior calyceal access during percutaneous nephrolithotomy: Determination of angle, efficacy, and outcomes.

INTRODUCTION: The classical lateromedial "bull's eye" technique for fluoroscopy-guided access for percutaneous nephrolithotomy (PCNL) may be inappropriate for a superior calyx puncture since its infundibulum has a craniocaudal (CC) orientation. We evaluated a modified bull's eye technique in a CC orientation (craniocaudal bull's eye [CCBE]) for superior calyceal access during PCNL.

METHODS: In an Institutional Review Board-approved, two-phase study, we evaluated the ideal angle for CC puncture in 24 patients who underwent CT scans for unrelated indications. Subsequently, patients planned for superior pole access PCNL were prospectively enrolled for the study. The maximum CC angle allowing puncture below the 11th rib, time to puncture, number of attempts required for successful punctures, and outcomes, including complications, were recorded.

RESULTS: CT scans of 24 patients were reviewed, and the ideal angle for CC rotation for the left and right kidney was 68.6° ± 4.5° and 68.1° ± 7.3°, respectively. All these would have resulted in access above the 10th rib. The CCBE technique was then used in 24 other subjects and was successful in 23, requiring a single attempt in 21 of them. The median angles of CC rotation, puncture time, and fluoroscopy screening time were 15°, 205 s, and 36 s, respectively. There were no postoperative complications.

CONCLUSIONS: Superior calyceal access can be achieved using a 15° CCBE technique. This is safe and successful in most patients with a single attempt and short fluoroscopy time.