Category: Clinical Stones: Ureteroscopy

MP24-22 - Modified Patient Positioning in Retrograde Intrarenal Surgery (RIRS): A Prospective Randomized Comparative Study

Sun, Sep 23
10:00 AM - 12:00 PM

Introduction & Objective : Recent studies indicate that CT analysis of the incidence of residual fragments (RF) following RIRS for renal stones is much worse than expected, even in expert hands.  Most of these fragments are in the lower pole of the kidney and can lead to future symptomatic stone episodes.  We investigated modifying the patient position during laser lithotripsy of renal stones to diminish the presence of RF on postoperative imaging.  We randomized patients into standard position (S) and a modified (M) position (15˚ Trendelenburg and 15˚ airplane) during RIRS.


Methods : In this IRB approved prospective, randomized study, patients were included if they were undergoing RIRS for intrarenal stone removal. Patients were excluded if they had kidney abnormalities, pre-existing ureteral stents, or a medical condition that precludes the use of Trendelenburg position (e.g. congestive heart failure) and were randomized into the S or M position. Demographics, comorbidities, and all relevant operative parameters were collected. We determined stone free rates using renal ultrasound and x-ray (KUB) by 1-month follow-up. Secondary aims include comparing operative times, post-operative pain levels, and pain medication usage.  One Way ANOVA, Chiand Fischer’s Exact tests were conducted.


Results : 64 patients have been enrolled and randomized. The 2 groups had similar patient and stone factors. Currently, 22 S group and 20 M group patients have completed the study with follow-up imaging. Operative time was greater in the M group, approaching statistical significance.  Of patients who completed the study, 77% (17/22) of S group patients and 95% (19/20) of M group patients were stone free  (p=0.05). Post-operative pain scores and pain medications required by each group were not different. Table 1shows our results.


Conclusions :

Tthe M position required more OR time, possibly due the fragments being able to be retrieved more completely by staying in a medial and superior location, and the benefit was greater stone free rates compared to the standard postion. These preliminary results suggest that changing patient position during laser lithotripsy of intrarenal stones improves stone free rates, and may prevent future stone episodes.

William M. Atallah

Assistant Professor of Urology, Icahn School of Medicine at Mount Sinai
Icahn School of Medicine at Mount Sinai
New York, New York

William Michael Atallah, MD, MPH
Assistant Professor of Urology, Icahn School of Medicine at Mount Sinai
Assistant Professor of Urology, Elmhurst Hospital

Stephanie Purnell

Research Fellow
Icahn School of Medicine at Mount Sinai
New York, New York

Blair Gallante

Research Coordinator
Icahn School of Medicine at Mount Sinai
New York, New York

Mantu Gupta

Chairman of Urology
Mount Sinai West and Mount Sinai St. Luke's
New York, New York

Ryan Chandhoke

Fellow
Mount Sinai West
New York, New York

Ryan Chandhoke, MD, MBA, completed MD at Tufts Univeristy School of Medicine. Completed Urology residency at UC Irvine School of Medicine. Current Endourology fellow at Mount Sinai West under the tutelage of Dr. Mantu Gupta.