單雙側椎板開孔術及椎板切除術目前已普遍應用在腰椎椎管狹窄症候群(Spinal stenosis syndrome)的減壓處理，且已都有良好的減壓效果及手術成功率。近年來，微創手術因為傷口小及術後復原快，單側椎板開孔術應用在腰椎雙邊減壓的方法漸漸盛行，但手術難度較高且繁雜。而在過去的研究顯示，單側的椎板開孔術比雙側的椎板開孔術有較多的併發症產生，如硬膜下出血及撕裂。特別是目前針對單雙側椎板開孔術的部分，目前並沒有相關的生物力學分析。因此，本研究目的為比較不同減壓手術後對於脊椎穩定度的影響，並進一步比較其生物力學特性，以找出符合臨床狀況且能保持力學穩定度之減壓手術型態，做為臨床醫師手術參考之依據。
本研究的第一部份為使用十隻豬腰椎進行體外實驗，模擬三種不同手術型態，每個樣本(L2-L5)會測試包含手術前、單側椎板開孔術、雙側椎板開孔術及椎板切除術共四種不同狀況，配合材料試驗機及自行設計之動作治具模擬腰椎彎曲及伸展的動作，輔以動作分析系統及應變規探討椎間活動度及椎體的應變狀況，以做為脊椎穩定度評估之指標。
結果顯示單側和雙側椎板開孔術在腰椎彎曲及伸展的模擬動作下，椎間活動度(L3-L4 及 L4-L5)並無顯著差異，椎板切除術則與其他三組都有顯著差異；在椎體應變量的分析也有同樣的趨勢，單側和雙側椎板開孔術並無顯著差異。
為進一步探討更多的生物力學參數及控制人與豬腰椎的差異，本研究的第二部分為根據一成人腰椎影像建立有限元素模型，共分成手術前、單側椎板開孔術、雙側椎板開孔術及椎板切除術共四種狀況模擬腰椎彎曲、伸展、側彎及旋轉，結果顯示單雙側椎板開孔術無論在椎間活動度、椎體等效應力及小面關節應力的表現上大致相同，進一步發現後縱韌帶在腰椎彎曲及前縱韌帶在腰椎伸展的張力在雙側椎板開孔術會比單側大，彎曲前後分別是211N及230N，伸展前後分別是338N及365N，證明脊椎韌帶可能會因為微小結構的變化而保留活動度，由此可知若患者的韌帶之功能完整，臨床上可建議實行雙測椎板開孔術。
總結以上結果發現，椎板開孔術比椎板切除術有較好的術後穩定性，在單側及雙側的椎板開孔術則並無發現有顯著的穩定度差異。以生物力學的觀點來看，雙側椎板開孔術在術後初期可與單側椎板開孔術保留相同的脊椎穩定性。

Unilateral laminotomy, bilateral laminotomies, and laminectomy have been widely used for managing spinal stenosis syndrome and all were successful decompression methods. In recent years, minimally-invasive concepts have been becoming more popular due to the shorter recovery time and involve removal of smaller amounts of important structures. Unilateral laminotomy was one of the minimally invasive decompression surgeries. Hence, it rated technically much more demanding than bilateral laminotomies and linked with more perioperative complications, such as dural hematoma and dural tear. However, no complete kinematic data and relative biomechanical analysis for evaluating spinal instability treated with unilateral and bilateral laminotomies. Therefore, the purpose of this study was to compare the stability of various decompression methods and to analyze the biomechanical characteristic. This study was expected to provide the selection for surgeon to decide what the decompressions methods should involve.
The first part of this study involved using 10 porcine lumbar spines in vitro to simulate three decompression surgeries. Intact, unilateral laminotomies, bilateral laminotomies, and laminectomies were tested using a mechanical testing machine and self-design jigs for each sample (L2–L5). During flexion and extension, the spinal segment kinematics was captured using a motion tracking system, and the strain was measured using a strain gauge.
The results indicated no significant differences in range of motion (L3–L4 and L4–L5) during flexion and extension between unilateral and bilateral laminotomies, whereas statistically significant findings were observed for laminectomies. The results for vertebral body strain were the same as those for range of motion, with no significant differences between unilateral and bilateral laminotomies.
To further explore the biomechanical differences between the human and porcine lumbar spine, the second part of this study entailed constructing a finite element model to analyze flexion, extension, lateral bending, and axial rotation. The model was used to simulate unilateral and bilateral laminotomies, and laminectomies at L3–-L4 and L4–L5. Similar stabilities in range of motion, posterior element stress, and facet contact force were observed between unilateral and bilateral laminotomies. This study found that the posterior longitudinal ligament during flexion and the anterior longitudinal ligament during extension were more active in bilateral than unilateral approaches (211 N vs. 230 N after flexion and 338 N vs. 365 N after extension). This study determined that the lumbar ligaments preserved the lumbar motion after the structures were modified. If the ligaments’ function of patients were normal, the bilateral laminotomies were suitable applied.
In summary, greater spinal stability was found for laminotomies compared with laminectomies, with no significant differences between bilateral and unilateral laminotomies. From the biomechanical perspective, bilateral laminotomies seem to maintain stability similar to that of unilateral laminotomies in short-term follow-ups.

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