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Watanabe, Ichiro; Masaki, Riko; Min, Nuo; Oshikawa, Naohiro; Okubo, Kimie; Sugimura, Hidezou; Kojima, Toshiaki; Saito, Satoshi; Ozawa, Yukio; Kanmatsuse, Katsuo

doi:10.1023/a:1014140104777

Cited by 63 publications

(11 citation statements)

References 22 publications

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“…It is associated with current delivery at high power and prolonging the duration of RF delivery in cooled tip RF [11]. Watanabe et al [4] reported that by using cooled tip, depth and volume of myocardial lesion were significantly larger in dogs. For creating a larger lesion with less accurate targeting, bipolar RF with water-cooled tip is advantageous in various procedures of pain management of severe degenerative changes or failed back surgery syndrome in which accurate placement of electrode is difficult [5,12].…”

Section: Discussionmentioning

confidence: 99%

“…For this purpose, accurate prediction of lesion created by ablation is essential for less morbidity and more satisfying result especially in pain management. Water-cooled electrodes are capable of creating larger lesions than non cooled ones by removing heat from adjacent tissue and deliver power without causing high impedance and tissue charring [4]. By comparing the maximum surface area formed by conventional RF and cooled RF in egg white, these benefits of water-cooled RF could be specified.…”

Section: Introductionmentioning

confidence: 99%

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Morphologic Analysis of Water-Cooled Bipolar Radiofrequency lesions on Egg White in Vitro

et al. 2012

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BackgroundThe aim of this study was to document the optimal spacing of two cannulae to form continuous strip lesions and maximal surface area by using water-cooled bipolar radiofrequency technology.MethodsTwo water-cooled needle probes (15 cm length, 18-gauge probe with 6 mm electrode tip) were placed in a parallel position 10, 20, 24, 26, and 28 mm apart and submerged in egg white. Temperatures of the probes were raised from 35℃ to 90℃ and the progress of lesion formation was photographed every 1 minute with the increase of the tip temperature. Approximately 30 photographs were taken. The resultant surface areas of the lesions were measured with the digital image program.ResultsContinuous strip lesions were formed when the cannulae were spaced 24 mm or less apart; monopolar lesions around each cannula resulted if they were spaced more than 26 mm apart. Maximal surface areas through the formation of continuous strip lesion were 221 mm2, 375 mm2, and 476 mm2 in 10, 20, and 24 mm, respectively. Summations of maximal surface area of each monopolar lesions were 394 mm2 and 103 mm2 in 26 and 28 mm, respectively.ConclusionsWater-cooled bipolar Radiofrequency technology creates continuous "strip" lesions proportional in size to the distance between the probes till the distance between cannulae is 24 mm or less. Spacing the cannulae 24 mm apart and treating about 80℃ for 24 minutes maximizes the surface area of the lesion.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Morphologic Analysis of Water-Cooled Bipolar Radiofrequency lesions on Egg White in Vitro

et al. 2012

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“…These internally cooled radiofrequency electrodes act as heat sinks that remove heat from tissue adjacent to the electrode. Cooling can lead to larger lesions because it can remove heat from the tissue adjacent to the electrode tip, preventing charring of tissue and maintaining a low impedance to allow dissipation of heat to a larger area 7. As a result, lesions of a larger volume could be produced compared with noncooled electrodes 10,11.…”

Section: Methodsmentioning

confidence: 99%

“…Cooled radiofrequency is a novel technique whereby internally cooled radiofrequency probes can lead to larger lesions 7. By treating a greater area of tissue lateral to the posterior sacral foramina, the chance of disrupting the sacral lateral branches will be higher.…”

Section: Introductionmentioning

confidence: 99%

Cooled radiofrequency denervation for treatment of sacroiliac joint pain: two-year results from 20 cases

Hadi²,

Pasutharnchat³

et al. 2013

JPR

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BackgroundSacroiliac joint pain is a common cause of chronic low back pain. Different techniques for radiofrequency denervation of the sacroiliac joint have been used to treat this condition. However, results have been inconsistent because the variable sensory supply to the sacroiliac joint is difficult to disrupt completely using conventional radiofrequency. Cooled radiofrequency is a novel technique that uses internally cooled radiofrequency probes to enlarge lesion size, thereby increasing the chance of completely denervating the sacroiliac joint. The objective of this study was to evaluate the efficacy of cooled radiofrequency denervation using the SInergy™ cooled radiofrequency system for sacroiliac joint pain.MethodsThe charts of 20 patients with chronic sacroiliac joint pain who had undergone denervation using the SInergy™ cooled radiofrequency system were reviewed at two years following the procedure. Outcome measures included the Numeric Rating Scale for pain intensity, Patient Global Impression of Change, and Global Perceived Effect for patient satisfaction.ResultsFifteen of 20 patients showed a significant reduction in pain (a decrease of at least three points on the Numeric Rating Scale). Mean Numeric Rating Scale for pain decreased from 7.4 ± 1.4 to 3.1 ± 2.5, mean Patient Global Impression of Change was “improved” (1.4 ± 1.5), and Global Perceived Effect was reported to be positive in 16 patients at two years following the procedure.ConclusionCooled radiofrequency denervation showed long-term efficacy for up to two years in the treatment of sacroiliac joint pain.

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“…Design of the wet electrode enables perfusion of the hypertonic saline solution into the tumor region with uncontrollable and irregular enlarged treatment area [17,18]. Design of the cooled-tip electrodes allows circulation of the cooling agents inside the electrode, which helps lower the temperature on the contact surface, thus slows down local water loss rate, and eventually increases the coagulation volume up to 50% [19]. However there also exists regions with evaporation which blocks the RF energy transportation [20,21].…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the influence of water evaporation on radiofrequency ablation

et al. 2013

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BackgroundRadiofrequency ablation is a promising minimal invasive treatment for tumor. However, water loss due to evaporation has been a major issue blocking further RF energy transmission and correspondently eliminating the therapeutic outcome of the treatment.MethodA 2D symmetric cylindrical mathematical model coupling the transport of the electrical current, heat, and the evaporation process in the tissue, has been developed to simulate the treatment process and investigate the influence of the excessive evaporation of the water on the treatment.ResultsOur results show that the largest specific absorption rate (Q SAR ) occurs at the edge of the circular surface of the electrode. When excessive evaporation takes place, the water dehydration rate in this region is the highest, and after a certain time, the dehydrated tissue blocks the electrical energy transmission in the radial direction. It is found that there is an interval as long as 65 s between the beginning of the evaporation and the increase of the tissue impedance. The model is further used to investigate whether purposely terminating the treatment for a while allowing diffusion of the liquid water into the evaporated region would help. Results show it has no obvious improvement enlarging the treatment volume. Treatment with the cooled-tip electrode is also studied. It is found that the cooling conditions of the inside agent greatly affect the water loss pattern. When the convection coefficient of the cooling agent increases, excessive evaporation will start from near the central axis of the tissue cylinder instead of the edge of the electrode, and the coagulation volume obviously enlarges before a sudden increase of the impedance. It is also found that a higher convection coefficient will extend the treatment time. Though the sudden increase of the tissue impedance could be delayed by a larger convection coefficient; the rate of the impedance increase is also more dramatic compared to the case with smaller convection coefficient.ConclusionThe mathematical model simulates the water evaporation and diffusion during radiofrequency ablation and may be used for better clinical design of radiofrequency equipment and treatment protocol planning.

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Cited by 63 publications

References 22 publications

Morphologic Analysis of Water-Cooled Bipolar Radiofrequency lesions on Egg White in Vitro

Morphologic Analysis of Water-Cooled Bipolar Radiofrequency lesions on Egg White in Vitro

Cooled radiofrequency denervation for treatment of sacroiliac joint pain: two-year results from 20 cases

Numerical study of the influence of water evaporation on radiofrequency ablation

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