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Radiofrequency ablation of the gastrointestinal tract with a stent-like electrode: experimental study.

Byun JN, Kang SG, Choi JY, Kim DH, Lee JM, Kim YC, Ki KH, Lee CG - Korean J Radiol (2003 Jan-Mar)

Bottom Line: 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.The gross and histologic changes occurring showed close correlation under all six sets of conditions.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Diagnostic Radiology, Chosun University College of Medicine, Gwangju, Korea.

ABSTRACT

Objective: To assess the technical feasibility of a newly designed stent-like electrode in rabbits.

Materials and 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.

Conclusion: 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.

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Related in: MedlinePlus

Gross findings just after RF ablation.A. Minimal change is noted after 10 W / 1-min ablation (arrow).B. Dark-colored hematoma is noted after 20 W / 1-min ablation (arrow).C. Larger hematoma is noted after 30 W / 1-min ablation (arrow).D. Two-week follow-up after 20 W / 2-min ablation. The duodenum was perforated at three different sites, at which it adhered to adjacent organs such as the liver (large arrow), abdominal wall (arrowhead), and colon (small arrow).
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Figure 7: Gross findings just after RF ablation.A. Minimal change is noted after 10 W / 1-min ablation (arrow).B. Dark-colored hematoma is noted after 20 W / 1-min ablation (arrow).C. Larger hematoma is noted after 30 W / 1-min ablation (arrow).D. Two-week follow-up after 20 W / 2-min ablation. The duodenum was perforated at three different sites, at which it adhered to adjacent organs such as the liver (large arrow), abdominal wall (arrowhead), and colon (small arrow).

Mentions: RF ablation using the stent-like electrode was technically successful in all 14 rabbits. During ablation of the duodenum, impedance of between 60 and 120 ohms was maintained. During the 4-week follow-up period, three of eight rabbits in the 2-min group died. In two rabbits, impedance increased rapidly (within 75 to 90 sec) and both animals died within one day of the procedure. One rabbit to which we applied RFA at power levels of 10, 20, and 30 watts for 2 min died 7 days after the procedure. Three animals (two in the 1-min group and one in the 2-min group) were sacrificed at the end of the 2nd week after ablation, and two more (both in the 1-min group) at the end of the 4th week (Table 1). During the RF procedure, three sites were perforated and the duodenum was seen to adhere to adjacent organs such as the liver, abdominal wall, and colon (Fig. 7).


Radiofrequency ablation of the gastrointestinal tract with a stent-like electrode: experimental study.

Byun JN, Kang SG, Choi JY, Kim DH, Lee JM, Kim YC, Ki KH, Lee CG - Korean J Radiol (2003 Jan-Mar)

Gross findings just after RF ablation.A. Minimal change is noted after 10 W / 1-min ablation (arrow).B. Dark-colored hematoma is noted after 20 W / 1-min ablation (arrow).C. Larger hematoma is noted after 30 W / 1-min ablation (arrow).D. Two-week follow-up after 20 W / 2-min ablation. The duodenum was perforated at three different sites, at which it adhered to adjacent organs such as the liver (large arrow), abdominal wall (arrowhead), and colon (small arrow).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2698054&req=5

Figure 7: Gross findings just after RF ablation.A. Minimal change is noted after 10 W / 1-min ablation (arrow).B. Dark-colored hematoma is noted after 20 W / 1-min ablation (arrow).C. Larger hematoma is noted after 30 W / 1-min ablation (arrow).D. Two-week follow-up after 20 W / 2-min ablation. The duodenum was perforated at three different sites, at which it adhered to adjacent organs such as the liver (large arrow), abdominal wall (arrowhead), and colon (small arrow).
Mentions: RF ablation using the stent-like electrode was technically successful in all 14 rabbits. During ablation of the duodenum, impedance of between 60 and 120 ohms was maintained. During the 4-week follow-up period, three of eight rabbits in the 2-min group died. In two rabbits, impedance increased rapidly (within 75 to 90 sec) and both animals died within one day of the procedure. One rabbit to which we applied RFA at power levels of 10, 20, and 30 watts for 2 min died 7 days after the procedure. Three animals (two in the 1-min group and one in the 2-min group) were sacrificed at the end of the 2nd week after ablation, and two more (both in the 1-min group) at the end of the 4th week (Table 1). During the RF procedure, three sites were perforated and the duodenum was seen to adhere to adjacent organs such as the liver, abdominal wall, and colon (Fig. 7).

Bottom Line: 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.The gross and histologic changes occurring showed close correlation under all six sets of conditions.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Diagnostic Radiology, Chosun University College of Medicine, Gwangju, Korea.

ABSTRACT

Objective: To assess the technical feasibility of a newly designed stent-like electrode in rabbits.

Materials and 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.

Conclusion: 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.

Show MeSH
Related in: MedlinePlus