熱治療對恢復受傷害之椎間盤的功能完整性的探討

Abstract

目的：本研究欲探討均勻加熱對穿刺傷害後的椎間盤之孔隙的影響。 背景簡介：椎間盤內電熱凝手術(intradiscal electrothermal therapy，IDET)是一種微創的脊椎手術，關於IDET的作用機制尚未完全清楚，一般認為在加熱的過程中，膠原將發生收縮(60℃以上)，進而修復椎間環的裂隙，以及破壞椎間盤內的痛覺神經末梢，因而減輕疼痛。然而臨床報告顯示此手術的效益並似乎不是很明確。 材料與方法：使用六個月大的幼豬胸椎椎間盤作為試樣(T1-T14，16個椎間盤，前導實驗使用8個，模擬熱凝手術實驗使用8個)。前導實驗階段，我們使用22號到14號針連續穿刺椎間盤，每次穿刺後即進行「椎間盤體積-壓力關係量測」試驗(quantitative discomanometry test，QD test)以評估椎間盤的功能完整能，尋找出會對椎間盤造成顯著性傷害的號數針。在模擬熱凝手術實驗階段，以此號數針穿刺椎間盤後，即進行QD試驗，接著將試樣浸泡至60~65 ℃的水中16.5分鐘，之後將試樣放置室溫下浸泡於食鹽水1.5小時，再進行第二次QD試驗。從QD試驗中可得「椎間盤內壓力-注射量」關係曲線，從該曲線中定義5個參數：洩漏壓力、洩漏注射量、飽和壓力、飽和注射量和穩定壓力，評估椎間盤的功能完整性。 結果：前導實驗結果發現發現穿刺針的口徑大小對飽和注射量沒有顯著性的影響，而穿刺後的孔隙愈大，椎間盤可承受的飽和壓力明顯地下降，且使用17號針或口徑大於17號的穿刺針進行穿刺後，椎間盤可承受的飽和壓力在1 MPa以下。模擬熱凝手術實驗以17號針穿刺椎間盤，結果顯示加熱8分鐘後，椎間環內的溫度已達60 ℃以上。加熱後，洩漏壓力、飽和壓力和穩定壓力皆明顯地下降，而洩漏注射量與飽和注射量加熱前後無明顯的差異性。 結論：本研究結果顯示加熱經穿刺的椎間盤無法改善椎間盤的功能完整性，我們認為椎間環的孔隙加熱後並沒有發生收縮，可能還更加擴大，使椎間盤的功能完整性降低。

Objective： The purpose of this study was to evaluate the effect of the heat treatment on shrinkage of anular fissure. Summary of Background Data：Intradiscal electrothermal therapy (IDET) is a minimally invasive surgical treatment for discogenic pain. The heat given by IDET coagulates the collagen fibers and destroys the nociceptors, thereby shrinking the anular tears and decreasing pain. However, the benefits of IDET are uncertain. Methods：16 half vertebra-disc-half vertebra segments were dissected from the porcine thoracic spines. The study was divided into two experiments. For the first experiment, eight specimens were punctured through the anulus with increasing needle size, ranging from 22G to 14G. The integrity of the disc was evaluated by a quantitative discomanometry (QD) test after each anular puncture to find the optimal needle gauge that induce significant disc injury. For the second experiment, each specimen received an anular puncture with the optimal needle size. The sample was incubated at 60~65°C in saline bath for 16.5 minutes, followed by 1.5 hours at room temperature. The QD test was conducted before the heat treatment and after the recovery. After each QD test, the pressure-volume curve was plotted. Five parameters were obtained from each pressure-volume (PV) curve, including leakage pressure and volume, saturation pressure and volume, and steady-state pressure. These parameters were used to evaluate the integrity of the disc. Result：The results of the first experiment showed a significant decrease in the saturation pressure with increasing needle diameter; however, there was no change in the saturation volume. The saturation pressure induced by a 17G needle or larger was leass than 1 MPa. In the second experiment, the discs were punctured with a 17G needle. The results showed that the temperature of inner anulus fibrosus achieved a temperature above 60°C at 8 minutes post heat treatment. The leakage pressure, saturation pressure, and steady-state pressure decreased significantly after the heat treatment, but the leakage and saturation volume did not significantly change. Conclusion：The integrity of disc did not recover after heat treatment; therefore, the shrinkage of the annular fissure, due to the heat treatment, was not significant after the heat treatment.