3-DOF Force-Sensing Motorized Micro-Forceps for Robot-Assisted Vitreoretinal Surgery

Area of Science:

• Ophthalmic surgery
• Biomedical engineering
• Surgical instrumentation

Background:

• Membrane peeling in vitreoretinal surgery requires delicate force application, often imperceptible to surgeons.
• Previous tools used fiber Bragg grating (FBG) sensors for 2D force detection.
• A need exists for instruments capable of measuring forces in all three dimensions.

Purpose of the Study:

• To develop and validate a novel ophthalmic surgical tool with enhanced FBG sensors for 3D force measurement.
• To compare linear and nonlinear force computation methods for accuracy and consistency.
• To improve precision in delicate surgical procedures like membrane peeling.

Main Methods:

• Integration of an additional FBG sensor to capture axial forces, alongside existing transverse sensors.
• Development of a compact motorized unit for grasping functionality.
• Investigation of linear regression and nonlinear Bernstein polynomial fitting methods for force computation.
• Experimental validation including repeatability tests, calibration, and performance assessment.

Main Results:

• The new tool demonstrates high sensor wavelength repeatability (within 2 pm).
• Linear fitting showed significant root mean square (rms) error (>3 mN) in axial force measurement.
• Nonlinear fitting provided consistent and accurate 3D force measurements (rms error <0.15 mN transverse, <2 mN axial).

Conclusions:

• The developed 3D force-sensing ophthalmic tool significantly enhances measurement accuracy, particularly with the nonlinear fitting method.
• This technology offers improved precision for intricate surgical tasks, potentially reducing complications.
• The nonlinear method is crucial for reliable measurement of both transverse and axial forces in surgical applications.