Purpose

To measure the ablation zone temperature and nontarget tissue temperature during radiofrequency (RF) ablation in bone containing metal instrumentation versus no metal instrumentation (control group).

Materials and Methods

Ex vivo experiments were performed on 15 swine vertebrae (control, n = 5; titanium screw, n = 5; stainless steel screw, n = 5). Screws and RF ablation probe were inserted identically under fluoroscopy. During RF ablation (3 W, 5 minutes), temperature was measured 10 mm from RF ablation centerpoint and in muscle contacting the screw. Magnetic resonance (MR) imaging, gross pathologic, and histopathologic analyses were performed on 1 specimen from each group.

Results

Ablation zone temperatures at 2.5 and 5 minutes increased by 12.2 °C ± 2.6 °C and 21.5 °C ± 2.1 °C (control); 11.0 °C ± 4.1 °C and 20.0 °C ± 2.9 °C (juxta-titanium screw), and 10.0 °C ± 3.4 °C and 17.2 °C ± 3.5 °C (juxta–stainless steel) screw; differences among groups did not reach significance by analysis of variance (P = .87). Mixed-effects linear regression revealed a statistically significant increase in temperature over time in all 3 groups (4.2 °C/min ± 0.4 °C/min, P < .001). Compared with the control, there was no significant difference in the temperature change over time for titanium (−0.3 °C/min ± 0.5 °C/min, P = .53) or steel groups (−0.4 °C/min ± 0.5 °C/min, P = .38). The mean screw temperature at the final time point did not show a statistically significant change compared with baseline in either the titanium group (−1.2 °C ± 2.3 °C, P = .50) or steel group (2.6 °C ± 2.9 °C, P = .11). MR imaging and pathologic analyses revealed homogeneous ablation without sparing of the peri-hardware zones.

Conclusions

Adjacent metallic instrumentation did not affect the rate of or absolute increase in temperature in the ablation zone, did not create peri–metallic ablation inhomogeneities, and did not result in significant nontarget heating of muscle tissue in contact with the metal instrumentation.

中文翻译：

---

近金属双极骨射频消融术：具有标本 MRI 和组织病理学相关性的体外模型热监测

目的

测量含金属器械与不含金属器械（对照组）的骨骼射频 (RF) 消融期间的消融区温度和非目标组织温度。

材料和方法

对 15 个猪椎骨进行离体实验（对照，n = 5；钛螺钉，n = 5；不锈钢螺钉，n = 5）。螺钉和 RF 消融探头在透视下完全相同地插入。在射频消融期间（3 W，5 分钟），在距离射频消融中心点 10 毫米处和接触螺钉的肌肉中测量温度。对每组的 1 个标本进行磁共振 (MR) 成像、大体病理学和组织病理学分析。

结果

消融区温度在 2.5 和 5 分钟时增加了 12.2 °C ± 2.6 °C 和 21.5 °C ± 2.1 °C（对照）；11.0 °C ± 4.1 °C 和 20.0 °C ± 2.9 °C（并置钛螺钉），以及 10.0 °C ± 3.4 °C 和 17.2 °C ± 3.5 °C（并置-不锈钢）螺钉；通过方差分析，组间差异未达到显着性 ( P  = .87)。混合效应线性回归显示所有 3 组的温度随时间显着升高 (4.2 °C/min ± 0.4 °C/min，P < .001 )。与对照组相比，钛组（-0.3 °C/min ± 0.5 °C/min， P  = .53）或钢组（-0.4 °C/min ± 0.5 °）随时间的温度变化无显着差异摄氏度/分钟，P = .38）。与钛组（−1.2 °C ± 2.3 °C， P  = .50）或钢组（2.6 °C ± 2.9 °C）的基线相比，最终时间点的平均螺杆温度未显示出统计学上的显着变化, P  = .11). MR 成像和病理分析显示均匀消融，不保留周围硬件区域。

结论

相邻的金属仪器不会影响消融区温度的速率或绝对升高，不会产生金属周围消融不均匀性，也不会导致与金属仪器接触的肌肉组织出现明显的非目标加热。