The T-Tilt Position: A Novel Modified Patient Position to Improve Stone-Free Rates in Retrograde Intrarenal Surgery
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Residual fragments following retrograde intrarenal surgery can lead to future stone episodes. The lower pole of the kidney presents a unique challenge as it is the most difficult location for retrograde intrarenal surgery. We investigated a modified patient position to increase stone-free rate by analyzing presence of residual fragments. We randomized patients into standard position and the T-Tilt position (15° Trendelenburg and 15° airplane away from the surgical side kidney).
Materials and Methods:
In this prospective, randomized study, patients were randomized into the standard or T-Tilt position. Demographics, comorbidities and operative parameters were collected. Stone-free rate was determined with renal ultrasound and x-ray at 1-month followup. Postoperative complications were recorded up to 1 month. Variables were compared using Kruskal-Wallis test for continuous variables and chi-square test for categorical variables.
A total of 138 patients were analyzed: 75 standard patients and 63 T-Tilt patients. The groups had similar patient and stone factors. The most common stone position was the lower pole (68.0% standard, 74.6% T-Tilt). Stone-free rates were significantly different: standard position was 76.7% and T-Tilt position was 92.1% (p=0.015). Stone-free rates for isolated lower pole stones were significantly different as well: standard position was 68.2% and T-Tilt position was 95.6% (p <0.001). Clavien-Dindo scores did not differ significantly (p=0.262).
The T-Tilt patient position was associated with higher stone-free rates. It is an atraumatic, cost-effective technique. These results suggest that modifying patient positioning during retrograde intrarenal surgery improves stone-free rates.
- 1. : Surgical management of stones: American Urological Association/Endourological Society Guideline. J Urol 2016; 196: 1153. Link, Google Scholar
- 2. : Steep infundibulopelvic angle as a new risk factor for flexible ureteroscope damage and complicated postoperative course. J Endourol 2018; 32: 597. Google Scholar
- 3. : Flexible ureterorenoscopy for lower pole stones: influence of the collecting system's anatomy. J Endourol 2017; 28: 146. Google Scholar
- 4. : Stone-free outcomes of flexible ureteroscopy for renal calculi utilizing computed tomography imaging. J Urol 2019; 124: 52. Google Scholar
- 5. : What is the stone-free rate following flexible ureteroscopy for kidney stones?Nat Rev Urol 2015; 12: 281. Google Scholar
- 6. : Treatment outcomes of retrograde intrarenal surgery for renal stones and predictive factors of stone-free. Korean J Urol 2010; 51: 777. Google Scholar
- 7. : Prediction of stone-free status after single-session retrograde intrarenal surgery for renal stones. Turk J Urol 2018; 44: 473. Google Scholar
- 8. : Working tools in flexible ureterorenoscopy—influence on flow and deflection: what does matter?J Endourol 2008; 22: 1639. Google Scholar
- 9. : Role of pelvicalyceal anatomy in the outcomes of retrograde intrarenal surgery (RIRS) for lower pole stones: outcomes with a systematic review of literature. Urolithiasis 2019; 48: 263. Google Scholar
- 10. : Ureteroscopic lithotripsy in the Trendelenburg position for extracting obstructive upper ureteral obstruction stones: a prospective, randomized, comparative trial. Scand J Urol 2019; 4: 291. Google Scholar
- 11. : Ureteroscopic treatment of lower pole calculi: comparison of lithotripsy in situ and after displacement. J Urol 2002; 168: 43. Link, Google Scholar
- 12. : Effect of positioning on ureteric stone retropulsion: 'gravity works.'BJU Int 2019; 123: 113. Google Scholar
- 13. : The effect of patient position on intrarenal anatomy. J Endourol 1999; 13: 257. Google Scholar
- 14. : Optimizing stone-free rates with ureteroscopy. Rev Urol 2015; 17: 160. Google Scholar
- 15. : The natural history of renal stone fragments following ureteroscopy. Urology 2011; 77: 564. Google Scholar
- 16. : A decision analysis of observation vs immediate reintervention for asymptomatic residual fragments less than 4 mm following ureteroscopic lithotripsy. Urol Pract 2019; 6: 294. Link, Google Scholar
- 17. : Complications of ureteroscopy: analysis of predictive factors. J Urol 2001; 166: 538. Link, Google Scholar
- 18. : Complications in robotic urological surgeries and how to avoid them: a systematic review. Arab J Urol 2018; 16: 285. Google Scholar
- 19. CONSORT: The CONSORT Flow Diagram. Available at http://www.consort-statement.org/consort-statement/flow-diagram. Google Scholar
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