Dynamics of epiretinal membrane removal off the retinal surface: a computer simulation project

Area of Science:

• Ophthalmology
• Biomechanical Engineering
• Surgical Simulation

Background:

• Epiretinal membranes (ERMs) can cause visual distortion and require surgical removal.
• Understanding the biomechanics of ERM peeling is crucial for minimizing intraoperative complications.
• Current surgical techniques lack precise guidance on optimal peeling angles.

Purpose of the Study:

• To determine the safest displacement angle (DA) for peeling epiretinal membranes using computer simulations.
• To analyze the distribution of maximum shear stress (MSS) during simulated ERM removal.
• To identify surgical parameters that reduce the risk of retinal damage.

Main Methods:

• Finite element analysis using ANSYS software to simulate ERM peeling.
• Geometrical data from optical coherence tomography of 30 eyes with ERMs.
• Assigning various Young's modulus values to ERM and retinal tissue.
• Calculating the ratio of maximum shear stress at attachment pegs to that on the membrane (P/E ratio) across nine displacement angles.

Main Results:

• Significant differences in MSS were observed at attachment pegs, ERM, and retina (p<0.05).
• A negative linear correlation between DA and MSS on the ERM was found when ERM's Young's modulus was higher.
• A positive linear correlation between DA and P/E ratio occurred when ERM's Young's modulus was lower.

Conclusions:

• Attachment pegs are the most vulnerable structures during ERM peeling.
• Altering the peeling direction can redistribute stress within the tissue complex.
• Peeling epiretinal membranes at a 165° DA appears to be a safer and more effective surgical strategy.