Presented by: Mouneeb Choudry MD
Mayo Clinic Arizona

Introduction

The surgical management of large stone burdens is a challenge which often necessitates staged ureteroscopy or a more invasive percutaneous nephrolithotomy. The CVAC Aspiration System is a novel, steerable catheter using irrigation and aspiration to evacuate stone debris after laser lithotripsy. Our study aims to evaluate the effectiveness of CVAC for treating large renal stones and, in particular, the effectiveness of CVAC in treating complex patients.

Materials

A retrospective, multi-institutional review was performed on patients from 2 major urologic centers with stones larger than 10 mm who underwent ureteroscopy with laser lithotripsy and CVAC outside of an ongoing randomized clinical trial. A sub-analysis was performed on all patients on active anticoagulation at the time of surgery and patients with neurologic conditions significantly limiting mobility (cerebral palsy, muscular dystrophy, spina bifida, quadriplegia). Categorical variables were summarized using relative frequencies and percentages. Continuous variables were summarized using mean ± standard deviation, median, and minimum and maximum. 

Results

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43 patients underwent the procedure. Mean pre-operative stone burden was 29 ± 12 mm and mean stone volume 3092 ± 5002 mm³. 24 patients had CT imaging at follow-up, and of those, up 33.3% (8) had no residual stone, 91.7% (22) had > 90% stone volume removed, 95.8% (23) had > 80% removed and 100% (24) had > 60% removed.  Mean stone volume reduction based on baseline stone burden varied between 93.8% and 98.9%.  21 patients were anticipated pre-operatively to need a secondary procedure. Of those, only 2 (9.5%) required a secondary procedure. 22 patients were deemed high-risk, 12 on anticoagulation or antiplatelet therapy and 10 with neurologic conditions. There was a 97% stone volume reduction in the anticoagulated cohort with postoperative CT imaging and an 83% stone volume reduction in the neurologic condition cohort with CT imaging. There were no complications secondary to the device and no post-operative admissions.

Conclusion

CVAC is a safe and effective procedure for large stone burdens, especially in high-risk patients, and should be considered to avoid the morbidity associated with repeat ureteroscopy or PCNL.

Funding

Calyxo, inc.

Lead Authors

Victoria Edmonds, MD
Mayo Clinic Arizona

Daniel Heidenberg, MD
Mayo Clinic Arizona

Kevin Wymer, MD
Mayo Clinic Arizona

Benjamin Borgert, MD
Florida State University School of Medicine

Karen Stern, MD
Mayo Clinic Arizona

Stuart Wolf Jr., MD
The University of Texas at Austin