應用於建立視網膜內限膜初始夾起機制之實驗探討

Abstract

內限膜（Internal Limiting Membrane, ILM）剝離手術為眼科視網膜手術中常見之精密手術，其成功與否往往取決於起始剝離捏夾出一小突起瓣膜，作為後續撕除之起點。由於ILM為厚度僅約數百奈米的彈性膜，手術中鑷子的末端設計與操作力量對於突起形成具有關鍵影響，然而相關物理行為與參數尚未有系統性探討。 本研究針對ILM起始剝離階段之物理行為進行實驗與模擬分析，提出一套可用於模擬手術過程之縮尺平台。為避免實際尺度下的微操作困難，系統將整體放大倍率進行設計，並建立一套可調控鑷子下壓與夾取的實驗平台。使用不同款式的鑷子，選擇依據為對應臨床常見的三種手術鑷設計，包含End Grasping型、ILM型與Sharkskin表面型，並透過粗糙化處理進行摩擦係數調整。膜材選用雞蛋殼膜作為彈性薄膜之替代，並對其厚度、黏附性與彈性進行測試與優化。 模擬透過有限元素分析（COMSOL Multiphysics）建立不同鑷子下壓軟材料之接觸模型，觀察不同下壓深度下的接觸面積、接觸壓力與剪應力等參數變化，進一步推估其對摩擦力與突起形成之影響。實驗則以逐步下壓方式觀察膜的變形行為，並將剝離結果依據突起形成狀態分為無突起（Missed）、有突起（Initiated）與破裂（Fractured）三類，進行量化分析。 綜合模擬與實驗結果顯示，鑷子設計對突起產生之影響主要來自末端接觸面積與摩擦特性，扁平型鑷子較容易形成穩定突起，粗糙化處理亦能有效提升剝離成功率。此外，模擬資料亦可補足實驗中難以量測之接觸參數，提供未來手術輔助裝置設計與鑷子優化參考依據。

Internal Limiting Membrane (ILM) peeling is a common but delicate retinal surgery, where success depends on the ability to form an initial membrane protrusion as the starting point for removal. Due to the ILM's nanometer-scale thickness and elasticity, the tip design and applied force of the surgical forceps are critical. However, the physical mechanisms behind this process remain insufficiently explored. This study investigates the initial peeling behavior through scaled-up experimental and simulation models. A controllable test platform was built using enlarged forceps tips—based on End Grasping, ILM, and Sharkskin designs—with additional surface roughening to adjust friction. Eggshell membrane was used as a substitute for the ILM, optimized for thickness and elasticity. Finite element simulations (COMSOL) modeled the contact between forceps tips and soft materials, yielding results for contact area, pressure, and normal force at various indentation depths. Experiments recorded deformation behavior and categorized peeling outcomes as Missed, Initiated, or Fractured. Results show that tip geometry and surface friction significantly affect protrusion formation. Flat and roughened tips improve initiation success. Simulations provide valuable data on contact parameters difficult to measure directly, offering guidance for future surgical tool and assistive system designs.