PD55-12: Ultra-low Dose Intraoperative CT Confirms Stone-free Status During PCNL Using Robotic Fluoroscopy Platform: A Prospective Quality Improvement Study

Xavier Glover*, Eric Ballon-Landa, Mark Sawyer, Denver, CO

Introduction: Stone-free status after percutaneous nephrolithotomy (PCNL) is a marker of treatment quality. Two groups described use of a robotic biplane fluoroscopy system (Artis Zeego, Siemens) for intraoperative CT during PCNL.  A series of 20 prone PCNLs was reported with median CT effective radiation dose (ERD) of 6.7 mSv.  We report initial results of an IRB approved QI study intended to reduce both need for further surgery and total radiation exposure.

Methods: Patients with kidney stones appropriate for PCNL are by default scheduled into a hybrid room containing an Artis Zeego system.  Supine PCNL is performed with access obtained by the urologist primarily using ultrasound guidance. CT imaging is obtained at the completion of stone treatment. To limit radiation, a low-resolution protocol with renal collimation is utilized. If residual calculi are identified, they are treated immediately, if possible. CT imaging can be repeated to verify complete treatment.

Results: From 8/21-10/21, four patients with kidney stones = 2cm had complete treatment verified with intraoperative CT. One patient was stone free after initial scan. Two had additional stone treatment performed after an initial scan found residual stone. One patient underwent imaging twice after an initial  non-diagnostic scana. A fifth patient with unusually complex stone disease had an intraoperative CT despite incomplete treatment to avoid a higher dose postoperative scan b. In all cases, excellent 3D imaging was achieved with a median ERD for CTs of 1.0 mSv. One patient’s combined ERD from standard fluoroscopy and two CTs was only 2.25 mSv (Table 1).

Conclusions: We report the first experience for intraoperative ultra-low dose CT imaging during PCNL.  Extremely low doses reasonably allow additional CT scans during an initial procedure, if further treatment is indicated.  Our facility is first in the world to establish intraoperative CT as a standard care for elective PCNL to reduce radiation for patients.

Source of Funding: None