Hori et al reported models for predicting stone recurrence following flexible ureteroscopy lithotripsy. This can help to identify a patient who may require closer monitoring. The authors are from Toho University in Japan.
Patient selection: status post stone removal by flexible ureteroscopy lithotripsy
Parameters:
(1) tallness (T) = maximum diameter in mm, from 3 to 71.5 mm
(2) occupied lesion (O) = location (U1, U2 or U3 undefined but probably refer to upper, middle or lower portion of the ureter)
(3) Hounsfield Units (HO), from 119 to 1618.3
Parameter
Findings
Points
tallness
< 10 mm
1
10 to 17 mm
2
17 to 24 mm
3
25 to 30 mm
4
> 30 mm
5
occupied lesion
ureter
1
middle or upper pole
2
upper pole
3
Hounsfield Units
< 620
1
620 to 1100
2
> 1100
3
Interpretation:
• minimum score: 3
• maximum score: 11
• A score >= 7 had a sensitivity of 0.73 and specificity of 0.77 for stone recurrence or residual stone.
• 75% of paitents with score >= 9 had residual stone.
Performance:
• The area under the ROC curve is 0.83.
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