Immediate effect of kidney cryoablation on renal arterial structure in a porcine model studied by imaging cryomicrotome.
OBJECTIVE
Injury to blood microvessels has a crucial role in effective cryoablation for renal masses. We visualized vascular injury induced by a clinically applied cryoablation instrument and established a microvascular diameter threshold for vascular damage.


METHODS
In 5 anesthetized pigs 1 kidney each was exposed and 3, 17 gauge cryoneedles were inserted in 1 pole. Tissue was exposed to freezing for 2 x 10 minutes with a 10-minute thaw between freezes. After nephrectomy the arteries were injected with fluorescence dyed casting material and the kidney was frozen to -20C and cut in 40 to 60 micron slices in the imaging cryomicrotome, where fluorescent images of the cutting plane of the bulk were obtained. This resulted in a 3-dimensional image of the arterial tree that was segmented, resulting in unbranched vessel segments. Histograms were constructed with the total segment length per diameter bin plotted as function of diameter.


RESULTS
The ablated zone was sharply demarcated on fluorescent and normal light images. Mean +/- SD diameter at the peak of the histogram from control areas was 152.4 +/- 5.3 micron. Compared to control areas the peak diameter of ablated areas was shifted to a larger diameter by an average of 25.4 +/- 2.6 micron.


CONCLUSIONS
Immediate renal cryoablation injury destroys arteries smaller than 180 micron. Branching structures of larger arteries remain anatomically intact and connected to vascular structures in surrounding tissue.
Lagerveld
Brunolf W
BW
Department of Urology, St Lucas Andreas Hospital, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
van Horssen
Pepijn
P
Pes
M Pilar Laguna
MP
van den Wijngaard
Jeroen P H M
JP
Streekstra
Geert J
GJ
de la Rosette
Jean J M C H
JJ
Wijkstra
Hessel
H
Spaan
Jos A E
JA
D000818:Animals; D001158:Arteries / Q000473:pathology / Q000601:surgery; D003452:Cryosurgery; D007668:Kidney / Q000098:blood supply* / Q000473:pathology / Q000601:surgery*; D008867:Microtomy; D023421:Models, Animal; D013552:Swine; D013997:Time Factors