[Haemostatic efficacy of a high intensity focused ultrasound applicator in lower pole partial nephrectomy in the pig].
OBJECTIVE
To evaluate the haemostatic property of a high intensity focused ultrasound (HIFU) applicator in lower pole partial nephrectomy in a porcine model.


METHODS
An applicator with a flat HIFU transducer operating at a frequency of 3.78 MHz was designed. Nine female pigs weighing between 35 and 39 kg were used. The kidneys of 5 pigs were used to characterize basic lesions, study haemostatic efficacy and measure the temperature rise in treated tissues. The following 4 pigs were treated by HIFU prior to bilateral lower pole partial nephrectomy. Treatment consisted of circumferential juxtaposition of basic lesions in the lower pole with vascular clamping. Haemostatic efficacy was evaluated immediately and 30 minutes after lower pole resection.


RESULTS
A 50-second ultrasound pulse with an intensity of 26 W/cm2 induced a full thickness lesion of the kidney, between 22 and 36 mm. Lesions were reproducible. The temperature rise observed in treated tissues was 62 +/- 12, 59 +/- 9 and 58 +/- 11 degrees C at distances of 15, 20 and 25 mm from the transducer, respectively. All lower pole partial nephrectomies were exsanguinated, except for one case (12.5%), in which a central renal artery was not controlled.


CONCLUSIONS
Our HIFU applicator is an excellent haemostatic tool ensuring effective coagulation of the renal parenchyma, allowing dry lower pole partial nephrectomy. Improvement of the ergonomics of this applicator and adaptation to laparoscopy are currently under investigation.
Murat
François-Joseph
FJ
Service d'Urologie, Hôpital Edouard Herriot, Lyon, France. gfj-murat@club-internet.fr
Lafon
Cyril
C
Cathignol
Dominique
D
Theillère
Yves
Y
Gelet
Albert
A
Chapelon
Jean-Yves
JY
Martin
Xavier
X
D000818:Animals; D005260:Female; D006489:Hemostatic Techniques; D009392:Nephrectomy / Q000379:methods*; D013552:Swine; D014464:Ultrasonic Therapy