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External validation of the T.O.HO. score and derivation of the modified T.O.HO. score for predicting stone-free status after flexible ureteroscopy in ureteral and renal stones
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  • Salih Polat,
  • Yavuz Onur Danacioglu,
  • Mustafa Soytas,
  • Serkan Yarımoğlu,
  • Omer Koras,
  • Ali Emre Fakir,
  • Kamil Gokhan Seker,
  • Tansu Degirmenci
Salih Polat
Amasya University Faculty of Medicine
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Yavuz Onur Danacioglu
Istanbul Bakirkoy Dr Sadi Konuk Training and Research Hospital
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Mustafa Soytas
Istanbul Medipol University Faculty of Medicine
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Serkan Yarımoğlu
Izmir Bozyaka Training and Research Hospital
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Omer Koras
Mustafa Kemal University Faculty of Medicine
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Ali Emre Fakir
Istanbul Bakirkoy Dr Sadi Konuk Training and Research Hospital
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Kamil Gokhan Seker
Mus State Hospital
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Tansu Degirmenci
Izmir Bozyaka Training and Research Hospital
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Abstract

Abstract The T.O.HO. scoring system was developed to predict stone-free status after flexible ureterenoscopy (fURS) lithotripsy applied for ureter and renal stones. This study aimed to perform the external validation of the T.O.HO. score in the Turkish population and propose a modification for this system. Material Methods Patients who underwent fURS for kidney and ureteral stones between January 2017 and January 2020 were retrospectively analyzed. The patient and stone characteristics and perioperative findings were noted. The T.O.HO. score was externally validated and compared with the STONE score. Stone-free parameters were evaluated with the multivariate analysis. Based on the results of this analysis, the T.O.HO. score was modified and internally validated. Results A total of 621 patients were included in the study. The stone-free rate was determined as 79.8% (496/621) after fURS. The regression analysis showed that stone area had better predictive power than stone diameter (p=0.025). Lower pole (reference), middle pole [odds ratio (OR)=0.492 p=0.016] and middle ureteral (OR=0.227, p=0.024) localizations, stone density (OR=1.001, p<0.001), and stone volume (OR = 1.008, p <0.001) were determined as independent predictive markers for stone-free status. Based on the effect size of the stone surface area in the nomogram, stone volume was divided into five categories, at 1-point intervals. The AUC values of the T.O.HO., STONE, and modified T.O.HO. score in predicting stone-free status were calculated as 0.758, 0.634, and 0.821, respectively. The modified T.O.HO. created by adding stone volume was statistically significantly superior to the original version (ROC curve comparison, p < 0.001). Conclusion The T.O.HO. score effectively predicted stone-free status after fURS. However, Modified T.O.HO. SS showed the best predictive performance compared with original T.O.HO. SS.

Peer review status:UNDER REVIEW

23 May 2021Submitted to International Journal of Clinical Practice
24 May 2021Assigned to Editor
24 May 2021Submission Checks Completed
02 Jun 2021Reviewer(s) Assigned