Radiofrequency ablation of the gastrointestinal tract with a stent-like electrode: experimental study.
OBJECTIVE
To assess the technical feasibility of a newly designed stent-like electrode in rabbits.


METHODS
A stent-like electrode was knitted from a single thread of nitinol wire and interconnected to a generator using similar wire. In order to gauge the extent of radiofrequency ablation (RFA), we measured the depth of the ablated area in cow liver using a combination of 180-sec time intervals and 20-watt power increments. For data processing, Cox regression analysis was used. RFA was also applied to the small intestine of rabbits using this stent-like electrode under six different sets of conditions: 10 watts for 1 min, 10 watts for 2 mins, 20 watts for 1 min, 20 watts for 2 mins, 30 watts for 1 min, and 30 watts for 2 mins. To determine the gross and microscopic findings, six animals were sacrificed immediately after the procedure and the results obtained under the different sets of conditions were correlated. Eight rabbits were monitored for 4 weeks prior to sacrifice.


RESULTS
For both ex-vivo and in-vivo ablations, the depth of the thermal lesion showed linear correlation with both the duration of RFA and the power applied. RFA of the duodenum was technically successful in all 14 rabbits. The acute changes occurring in the rabbits' small intestine included color change, cytoplasmic denaturation, fibrin deposition and hemorrhage, among which hemorrhage of the mucosal layer was the earliest finding. RF ablation for 2 mins at 30 watts caused serosal hemorrhage. The gross and histologic changes occurring showed close correlation under all six sets of conditions.


CONCLUSIONS
Use of the stent-like electrode proves technically feasible but to determine the nature of the chronic change occurring in the gastrointestinal tract after RF ablation, further investigation and long-term follow-up in animals are required.
Byun
Joo Nam
JN
Department of Diagnostic Radiology, Chosun University College of Medicine, Gwangju, Korea.
Kang
Sung-Gwon
SG
Choi
Jeong-Yeol
JY
Kim
Dong Hyun
DH
Lee
Jung Min
JM
Kim
Young Chul
YC
Ki
Keun Hong
KH
Lee
Chul Gap
CG
D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation; D002417:Cattle; D013505:Digestive System Surgical Procedures; D004386:Duodenum / Q000601:surgery*; D004566:Electrodes; D004867:Equipment Design; D008099:Liver / Q000601:surgery; D008297:Male; D016016:Proportional Hazards Models; D011817:Rabbits; D015607:Stents