Reducing residual forces in spinal fusion using a custom-built rod bending machine

Area of Science:

• Spinal Surgery
• Robotics in Medicine
• Surgical Navigation

Background:

• Manual rod contouring in spinal fusion is time-consuming and prone to errors.
• Improperly contoured rods can cause stress on pedicle screws, leading to loosening or pull-out.

Purpose of the Study:

• To develop and evaluate the first fully automated solution for spinal fusion rod bending.
• To leverage augmented reality and robotics for improved surgical accuracy and efficiency.

Main Methods:

• Utilized augmented reality for intraoperative digitization of screw positions.
• Integrated a custom-built robotic rod bending machine with a surgeon-computer interface.
• Employed custom test rigs to measure residual forces at the screw-bone interface.

Main Results:

• Achieved a significant reduction in average absolute residual forces (p=0.0015).
• Reduced average instrumentation time per screw.
• Significantly decreased reducer engagements per rod (p=0.0037).

Conclusions:

• The integration of augmented reality and robotics offers a promising approach to enhance spinal fusion surgery outcomes.
• This automated system minimizes reliance on individual surgeon skill, improving consistency and potentially reducing complications.