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
|
Location
|
Points
|
|
U1 (ureter)
|
0
|
|
U2 (ureter)
|
12
|
|
U3 (ureter)
|
5.7
|
|
upper pole
|
16.4
|
|
middle
|
12.6
|
|
lower pole
|
20.6
|
points for diameter in mm =
= (1.4598 * (score)) - 4.3796
points for Hounsfield Units =
= (0.0203 * (HU)) - 2.4208
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 151.1
value of X =
= (0.08091 * (score)) - 5.168
probability of failure =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.85.
