背景：
大約有百分之十五到百分之二十的人在一生中曾為下背痛所苦，下背痛的原因有多種，包括椎間盤突出、脊神經，脊神經根、背根神經節，硬腦膜以及關節突關節(facet joint) 等之病變. 治療方法也有許多種，包括休息、藥物治療、復健、手術等。而高頻熱凝是另一個選擇，尤其對關節突關節之退化引起的疼痛特別有效果，大約有七成到八成患者，會因高頻熱凝治療而改善症狀。但是大約半年內，大多數患者症狀會復發，因而我們想知道高頻熱凝止痛之可能機轉。
目的：
背根神經節是疼痛由脊神經傳入脊髓必經之處，我們想由實驗知道是否背根神經節細胞會因高頻熱凝療法而有所變化。另外,脊髓對於週邊的疼痛刺激，會在灰質背角(Dorsal horn)產生c-Fos活性。我們想知道高頻熱凝之後,當下肢遇到疼痛刺激時，其腰脊髓背角的c-Fos活性是否受影響。
方法：
將老鼠於右側第三、四、五腰椎邊做68℃，60秒之高頻熱凝後,分成四組，第一組於二天後做熱板腳底疼痛測試,之後以蜂毒注射於後腳掌背，取出腰椎第三、四、五節之脊髓，作c-Fos活性之測定，並取第三、四、五腰椎之兩側背根神經節，觀察細胞受損情形，第二、三、四組分別於一週、二週及四週後做上述實驗。
結果：
第一及第二組之疼痛測試，右側反應較遲緩，第三、四組無差異。背根神經節之實驗，四組之右側大、小細胞均有顯著之細胞受損情形。c-Fos之實驗，則四組左右側c-Fos活性並無顯著差異。
結論：
高頻熱凝確可短期減低下肢痛覺。高頻熱凝於腰椎附近會造成背根神經節細胞受損，但並不會降低蜂毒刺激腳掌引起之背角c-Fos活性。

Background:
Low back facet joint pain sometimes is treated by radiofrequency (RF) denervation. RF is effective but the recurrence rate is high. We want to know the mechanism of RF in pain-relief.
Objectives:
We tried to know the changes of dorsal root ganglia (DRGs) after RF near the facet joint . We also want to know whether of not the pain-induced c-Fos activity in dorsal horn will decrease after RF treatment..
Methods:
RF ( 68℃，60 sec ) was applied to right L3、L4 and L5 vertebrae (0.5 cm from midline) of rats. Then the rats were divided into 4 groups. In Gr I, 2days after RF, hot plate plantar test was performed. Then bee venom was injected in bilateral dorsal hind paws. After perfusion, L3、L4 and L5 spinal cord segments were taken for c-Fos study. Bilateral L 3、L4 and L5 DRGs were taken for neuron study. GrII, GrIII, and GrIV were studied 1 week, 2 weeks, 4 weeks after RF respectively.
Results:
Only GrI and GrII showed difference between right and left legs in plantar test. Right L3 L4 and L5 DRGs had neuron injury. There was no difference between left and right dorsal horns in the c-Fos study in all four groups.
Conclusion:
RF is effective in analgesic for a short time. DRG cells are injured after RF near the facet joint. RF can not reduce the dorsal horn c-Fos activity induced by bee venom.

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