Tsetse fly inspired steerable bone drill-a proof of concept

Area of Science:

• Biomedical Engineering
• Surgical Innovation
• Orthopedic Devices

Background:

• Current rigid bone drills limit pedicle screw fixation strength by preventing cortical bone layer engagement.
• Achieving stronger screw fixation requires accessing the denser cortical bone, a feat not possible with conventional straight drills.

Purpose of the Study:

• To develop and evaluate a single-plane steerable bone drill inspired by the tsetse fly for improved pedicle screw fixation.
• To assess the drill's ability to navigate cancellous bone and follow the cortical bone layer using wall guidance.

Main Methods:

• A steerable bone drill utilizing a flexible transmission with stacked leaf springs was designed.
• Proof-of-principle experiments were conducted using cancellous bone phantoms with varying mechanical properties.
• The drill's ability to steer along the cortical wall at different insertion angles was tested.

Main Results:

• The Tsetse Drill successfully drilled through cancellous bone phantoms simulating osteoporotic and healthy bone.
• The steerable drill effectively navigated and drilled along the cortical wall with insertion angles of 5°, 10°, and 15°.
• Wall guidance enabled the creation of curved tunnels.

Conclusions:

• The tsetse fly-inspired steerable drilling method is effective for bone applications.
• This technology allows drilling along the cortical bone layer, potentially increasing bone anchor fixation strength.
• The Tsetse Drill can reduce the risk of cortical breach and damage to surrounding anatomical structures.