Ultrasonography Is Not Inferior to Fluoroscopy to Guide Extracorporeal Shock Waves during Treatment of Renal and Upper Ureteric Calculi: A Randomized Prospective Study
Table 1
Summary of study results.
US group ( = 57)
FS group ( = 57)
Statistical analysis
Factors influencing SWL outcome
Stone-related factors
Stone size
Mean stone size (mm)(1)
9 (σ = 3)
8.5 (σ = 3)
= 0.29
Number of stones 0–4 mm
5
5
= 1
Number of stones 5–9 mm
30
30
= 1
Number of stones 10–20 mm
22
22
= 1
Stone composition(2)
Number of hard stones(3)
6 ( = 30)
4 ( = 25)
= 0.50
Stone position
Number of lower pole stones
22 (39%)
22 (39%)
= 1
Number of pyelum and PUJ stones
5 (9%)
8 (14%)
= 0.37
Number of upper pole stones
18 (31%)
8 (14%)
= 0.02
Number of midpolar stones
12 (21%)
19 (33%)
= 0.14
Stone density (HU)(4)
Mean stone density (HU)
665 (σ = 160, = 31)
740 (σ = 223, = 29)
= 0.10
Maximal stone density (HU)
965
1213
NA
Operator-related factors
Experience with both techniques
2 investigators with equal experience
NA
Patient-related factors
Mean BMI (kg/m2)
27 (σ = 3,8)
29 (σ = 3,3)
= 0.001
Mean skin-to-stone distance (mm)(5)
90 (σ = 13, =31)
104 (σ = 14, = 29)
< 0.001
Technique-related factors
Shock frequency (bpm)
60
= 1
Number of shocks
2500
= 1
Ramping protocol
Identical in both groups
NA
Mean energy (Joule)
49 (σ = 11)
53 (σ = 11)
= 0.002
Study outcomes
Clinical outcome
Number of stone-free patients
30
24
Noninferior(6)
Number of patients with asymptomatic residual fragments
15
16
Number of patients with a positive outcome(7)
45
40
Noninferior(6)
Number of patients needing additional therapy
6
9
Number of patients with no effect
6
8
Number of patients with a negative outcome(8)
12
17
Noninferior(6)
Number of ESWL sessions
Mean number of SWL sessions/patient
1.6 (σ = 0,7)
1.7 (σ = 0,7)
= 0.431
Positioning
Mean number of position changes/patient
8 (σ = 2)
6 (σ = 2)
= 0.008
Mean time to position/patient
9 (σ = 2)
5 (σ = 2)
< 0.001
Radiation
Mean DAP (mGy/cm2)/SWL session
0
3005 (σ = 601)
< 0.001
(1) Measured as longest stone distance on RX before the first SWL session. (2) Only 55/114 (48%) patients analysed their stone. (3) Calcium oxalate monohydrate (whewellite), cystine, or calcium phosphate (brushite) stones. (4) Hounsfield units as measured on CT abdomen. (5) Measured vertically in the US group and 45° in the FS group. (6) With a noninferiority margin of 10%. (7) Stone-free or asymptomatic residual fragments ≤ 4 mm. (8) Additional therapy or no effect.
