Biomechanics of Transforaminal Endoscopic Approaches
經椎間孔內鏡入路的生物力學研究
Study Design.
Biomechanical cadaveric study. Objective. The aim of this study was to compare the effect of transforaminal endoscopic approaches with open decompression procedures.
Summary of Background Data.
Clinical studies have repeatedly highlighted the benefits of endoscopic decompression, however, the biomechanical effects of endoscopic approaches (with and without injury to the disk) have not been studied up to now.
Materials and Methods.
Twelve spinal segments originating from four fresh-frozen cadavers were biomechanically tested in a loadcontrolled endoscopic transforaminal approach study. Segmental range of motion (ROM) after endoscopic approach was compared with segmental ROM after (1) microsurgical decompression with unilateral laminotomy and (2) midline decompression with bilateral laminotomy. In the intact state and after decompression, the segments were loaded in flexion-extension (FE), lateral shear (LS), lateral bending (LB), anterior shear (AS), and axial rotation (AR).
Results.
Vertebral segment ROM was comparable between the two endoscopic transforaminal approaches. However, there was a —statistically nonsignificant—trend for a larger ROM after accessing via the inside-out technique. FE: +3% versus +7%, P=0.484; LS: +1% versus +12%, P= 0.18; LB: +0.6% versus +9%, P=0.18; AS: +2% versus +11%, P= 0.31; AR: ?4% versus +5%, P= 0.18. No significant difference in vertebral segment ROM was seen between the transforaminal endoscopic approaches and open unilateral decompression. Vertebral segment ROM was significantly smaller with the transforaminal endoscopic approaches compared with midline decompression for almost all loading scenarios: FE: +4% versus +17%, P=0.005; AS: +6% versus 21%, P=0.007; AR: 0% versus +24%, P= 0.002.
Conclusion.
The transforaminal endoscopic intracanal technique preserves the native ROM of lumbar vertebral segments and shows a trend toward relative biomechanical superiority over the insideout technique and open decompression procedures.
Key words:
endoscopy, endoscopic spine surgery, endoscopic approach, endoscopic decompression, transforaminal, intracanal technique, inside-out technique, biomechanics, lumbar disk herniation, lumbar spine
研究設計：
尸體生物力學研究。目標。本研究的目的是比較經椎間孔內窺鏡入路與開放式減壓手術的效果。背景數據匯總。臨床研究一再強調內鏡下減壓的好處，然而，迄今為止尚未對內鏡入路(有無椎間盤損傷)的生物力學效應進行研究。
材料與方法：
在一項負荷控制內窺鏡下經椎間孔入路研究中，對來自4具新鮮冷凍尸體的12個脊柱節段進行了生物力學測試。比較內鏡下入路后的節段活動度(range of motion, ROM)與(1)單側椎板切開顯微減壓術和(2)雙側椎板切開中線減壓術后的節段活動范圍。在完整狀態和減壓后，對節段進行屈伸(FE)、側向剪切(LS)、側向彎曲(LB)、前向剪切(AS)和軸向旋轉(AR)加載。
結果：
兩種內鏡經椎間孔入路的椎節段活動范圍相當。然而，采用由內向外技術訪問后，活動范圍有統計學上不顯著的趨勢。FE: +3% vs +7%， P=0.484;LS: +1% vs +12%， P= 0.18;LB: +0.6% vs +9%， P=0.18;AS: +2% vs +11%， P= 0.31;AR:?4% vs . +5%， P= 0.18。經椎間孔內鏡入路與單側開放減壓術的椎體活動范圍差異無統計學意義。在幾乎所有的負重情況下，經椎間孔內鏡入路與中線減壓術相比，椎體活動范圍均顯著減小:FE: +4% vs . +17%， P=0.005;AS: +6%對21%，P=0.007;AR: 0% vs +24%， P= 0.002。
結論：
經椎間孔鏡椎管內技術保留了腰椎節段的原始活動度，并顯示出相對于內翻技術和開放減壓手術的生物力學優勢的趨勢。
關鍵詞：內窺鏡，脊柱內窺鏡手術，內窺鏡入路，內窺鏡減壓，經椎間孔，椎管內技術，內外技術，生物力學，腰椎間盤突出癥，腰椎
