Radiofrequency (RF) ablation of painful bone tumours and metastasis has quickly progressed from an experimental procedure to an established minimally invasive method for pain control. This review will describe the physics behind RF ablation technology. Osteoid osteomas were the first primary bone tumours to be treated in this manner, establishing RF ablation as the treatment modality of choice. A more recent development involves the use of RF ablation in painful bone metastases. In this setting, RF ablation complements radiation therapy. Its advantage lies in a more rapid onset of pain reduction (often at least by 2 points on a 10-point scale), and that radiation therapy can be employed concomittantly. It is important to remember that the aim of RF ablation in painful bone metastases is not curative, but palliation.
Catheter Ablation - Methods

Factors influencing the temperature-sensing accuracy of an ablation catheter are analyzed, in this paper, from the two aspects of the thermocouple temperature sensor, which are the TC length and the TC hole's diameter of the ablation electrode. Meanwhile, differences between products from different companies are given too.
Catheter Ablation ; methods ; Electrodes ; Temperature

Atrial Fibrillation ; surgery ; Catheter Ablation ; methods ; Humans

Atrial Fibrillation ; surgery ; Catheter Ablation ; methods ; Humans

OBJECTIVETo investigate the effectiveness and advantages of the Carto merge technique in guiding radiofrequency catheter ablation (RFCA) of permanent atrial fibrillation (AF).

METHODSA total of 15 patients with permanent AF underwent RFCA under guidance of the Carto merge technique. The virtual electroanatomical map of the left atrium (LA) and pulmonary veins (PVs) were reconstructed with Carto system during the procedure. Then the electroanatomical map was integrated with 3-D images of cardiac magnetic resonance angiography to form Carto merge map. Circumferential pulmonary vein ablation was performed first until complete PVs electric isolation confirmed by lasso catheter. If AF was not terminated, lesion lines on roof of LA, mitral isthmus, and tricuspid isthmus were produced. Finally direct current (DC) cardioversion were given if sinus rhythm did not return.

RESULTSAF were terminated spontaneously during RFCA in 2 patients, and by DC cardioversion in the remaining 13 patients. Persistent AF recurred on 24 hours, first week, and 5th week, respectively in three patients. The remaining 12 patients were all free of AF during follow-up (1-10 months). The success rate was 80% in the study.

CONCLUSIONSCarto merge technique can effectively guide RFCA of permanent AF. When combined with single Lasso mapping, it can simplify the mapping and enhance the success rate of RFCA of permanent AF.

Catheter Ablation ; methods ; Humans ; Hypertension ; surgery ; Renal Artery ; Sympathectomy ; methods

Aged ; Catheter Ablation ; methods ; Female ; Hematoma ; surgery ; Humans ; Thrombosis ; surgery

To solve the problems of small one-time ablation range and easy charring of the tissue around the electrode associated with the tumor radiofrequency ablation needle, based on the multiphysical field coupling analysis software COMSOL, the effects of needle material, the number of sub needles and the bending angle of sub needles on the ablation effect of radiofrequency ablation electrode needle were studied. The results show that compared with titanium alloy and stainless steel, nickel titanium alloy has better radiofrequency energy transmission efficiency and it is the best material for electrode needle. The number of sub needles has a great influence on the average necrosis depth and the maximum necrosis diameter. Under the same conditions, the more the number of sub needles, the larger the volume of coagulation necrosis area. The bending angle of the needle has a great effect on the maximum diameter of the coagulated necrotic area, but has little effect on the average necrotic depth. Under the same other conditions, the coagulation necrosis area formed by ablation increased with the increase of the bending angle of the sub needle. For the three needles with bending angles of 60 °, 90 ° and 120 ° analyzed in this paper, the one with bending angle of 120 ° can obtain the largest coagulation necrosis area. In general, the design of nickel titanium alloy with 120 ° bending 8-pin is the optimal. The average depth of radiofrequency ablation necrosis area is 32.40 mm, and the maximum necrosis diameter is 52.65 mm. The above optimized design parameters can provide guidance for the structure and material design of tumor radiofrequency ablation needle.
Humans ; Needles ; Temperature ; Catheter Ablation/methods* ; Necrosis ; Neoplasms/surgery* ; Alloys

In order to optimize temperature monitoring, the mean of temperature measured by Copper-CuNi thermocouple (TC) was compared with the actual temperature. By the use of the temperature response curve of TC, the data from monitoring temperature were analyzed in regard to the depth of installation, the diameter of TC hole and the material of ablation electrode. The accuracy and real-time of TC with a depth of 3.5 mm were better than those of 2.5 mm or 3 mm, when TC was installed in the ablation electrode TC hole. However, the difference of real-time performance was not obvious. When TC was installed in different TC holes with diameter of 0.44 mm, 0.42 mm, 0.33 mm respectively, TC with the diameter of 0.33 mm TC hole was noted to be of higher accuracy and better real-time to response temperature, compared with others. In terms of material quality, the slope of platinum temperature response curve was greater than that of stainless steel, while the accuracy of sensor temperature changed inconspicuously. As a result, the monitoring device of temperature should be put to the heat source as nearly as possible. Also, platinum ablation electrode with better thermal conductivity should be chosen.
Catheter Ablation ; instrumentation ; methods ; Electrodes ; Equipment Design ; Humans ; Platinum ; Temperature

Atrial Fibrillation ; physiopathology ; surgery ; Catheter Ablation ; methods ; Humans ; Treatment Outcome