Feasibility study of a mini, bone-attached, robotic system for spinal operations: analysis and experiments

Area of Science:

• Robotics in Medicine
• Surgical Technology
• Biomechanical Engineering

Background:

• Spinal operations have a suboptimal success rate (70%-90%) due to disease complexity, patient selection, and anatomical challenges.
• Physician inexperience and intricate spinal anatomy contribute to technical difficulties in spinal surgeries.
• A miniature bone-attached robotic system offers potential to enhance surgical success rates, enable new procedures, and reduce patient recovery times and radiation exposure.

Purpose of the Study:

• To investigate a miniature robotic system attached to the spinous process for spinal operations.
• To quantify forces exerted by physicians during Kirschner wire insertion and bone drilling.
• To evaluate robotic system error caused by mechanical/anatomic deflection from applied forces.

Main Methods:

• A 6-DOF miniature sensor measured forces and moments during Kirschner wire insertion in soft and hard tissues (sheep and human cadaver).
• A theoretical model was developed to predict the robotic system's location error.
• The theoretical model was experimentally verified using cadaveric specimens.

Main Results:

• The theoretical model demonstrated strong agreement with experimental findings.
• The robotic system, attached to the spinous process, proved sufficiently rigid for accurate Kirschner wire guidance.
• Calculated system errors due to applied forces and moments were within acceptable limits, confirming feasibility.

Conclusions:

• The developed theoretical model is supported by experimental and clinical data.
• A miniature robotic guiding system can be reliably attached to the vertebral spinous process.
• The system's deflection and error are within permissible ranges for surgical application.