Department of Urology - Tel Aviv Sourasky Medical Center - Tel Aviv, Israel
Sackler Faculty of Medicine - Tel-Aviv University - Tel Aviv, Israel
Meir Medical Center - Kfar Saba, Israel
Shaarei Zedek Medical Center - Jerusalem, Israel
Santiago Richter, Wael Abu-Arfat*,Ami Farkash*, Ilan Leibovich
Introduction and Objective
Most available Lithotripters generate shock waves from one source only and use a shock frequency of 2 Hz, or are ECG gated (for arrhythmic patients). The Direx Duet is a Dual Head Lithotripter, able to operate at 2 Hz in each reflector, resulting in a total number of 4 shocks per second, delivered to the stone (4 Hz). The objective of this study is to investigate whether stone fragmentation at 4 Hz is as effective and safe as at 2 Hz, while reducing significantly the treatment time.
Methods
During the period of May through September 2004, 65 patients were treated randomly at two centers, with the Direx Duet at either 2 or 4 Hz. The procedure was performed under general (29) or epidural (36) anesthesia. Success was defined as either stone free or fragments of <4 mm, partial success as fragments of >4 mm and failure as no fragmentation. Patients were followed by KUB at 3-5 weeks after ESWL.
Results
There were 24 right and 41 left renal units, respectively. All stone parameters were comparable in both groups. Thirty patients were treated at 2 Hz and 35 patients at 4 Hz, under an identical protocol.
The tables show stones characteristics and intrarrenal location
| |
Stone Size |
5 mm
|
6-10mm
|
11-15mm
|
>16mm
|
Average
|
Size Range
|
| |
4 HZ
|
5
|
22 |
5
|
3
|
9.11 + 3.72
|
5-22 mm
|
| Frequency |
2HZ |
4
|
20
|
6
|
0 |
8.7 + 2.86
|
5-15 mm
|
Intrarenal Stone Location
| Frequency |
UC |
MC
|
LC
|
RP
|
UPJ
|
UU
|
MU
|
LU
|
| 4 HZ |
3 |
2
|
9
|
9
|
1
|
11
|
0
|
0
|
2 HZ
|
5 |
6
|
6
|
9
|
3
|
0
|
1
|
0
|
Comparitive Results
| Frequency |
Number Of
Stones Treated
|
Sucess |
Partial Fragments
(>4mm) Cases
|
Number Of
NF Cases
|
2 HZ
|
30 |
26 (87%)
|
1 (3%) |
3 (10%)
|
4 HZ
|
35 |
29 (83%) |
5 (14%)
|
1 (3%) |
1) Incidence Of Adverse Events
| |
Frequency |
4 HZ |
2 HZ
|
| |
Hematuria |
-
|
-
|
| Adv Event |
Renal Colic |
2 |
2 |
2) Average Treatment Time
| Trigger |
4 HZ
|
2 HZ
|
| Avg. Treatment |
9.69
|
16.06
|
Time (min)
|
(SD = 3.04)
|
(SD = 7.73) |
Re-treatment Rate
2 patients in each group had to be retreated at 3-4 weeks after ESWL.
Conclusion
The 4Hz Treatment Mode with the Direx Duet has similar side effects and effectiveness as the 2 Hz but is able to perform a typical SWL Treatment in less than 10 minutes.
| 
