Image Guided System for Intracranial

Neurosurgery 1

Project Overview

• Problem:– Neurosurgery is complicated, expensive, and not fully

accessible– McKnight Brain Institute developed surgical planning

software that generates a 3D printed mask guide– Mask cannot be sterilized, software is not accessible

• Solution:– Create an easy to use, web based interface for software– Design an articulating arm that can align with position

set by mask and maintain that position after sterilization

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Software Specifications

• Simple easy to follow user interface• Web Accessible• Ability to upload MRI/CT files• View target and entry point in all three

anatomical planes• Ability to view 3D model of patient head

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Software Overview• Developed a simple and easy to use web-

based user interface• No cost to develop• Not hardware dependent • Not browser dependent• Functional 3D model from MRI files

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Hardware Specifications

Mechanical interface for positioning of surgical probe according to target location specified by software-generated mask:– Simple, Easy to use articulating arm

• Pneumatic, passively locking device• Manual manipulation• Minimize size and weight

• Compatible w/ Medtronic articulating arm• 5 degrees of freedom• Maintain sterility: detachable probe head• Maintain accuracy of probe positioning ~2 mm

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Hardware Design Overview“Dumbbell” design• 5” rigid shaft• Ball joints• Cylinder enclosures

Pneumatic locking mechanism• Passively locks• Air pressure supplied

w/ foot pedal6

Pneumatic Locking Mechanism

• Stacks of washers and wave springs clamp ball

• Silicone tubing inflates to unclamp ball

• Ball freely moves while air pressure is supplied

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Test Overview

Tests were performed using a phantom to set a target point whose 3D coordinates can be measured in millimeters.1. Locking Mechanism Test

AIM: To assess the accuracy of the pneumatic locking mechanism.

• Unlock arm, line up to target position, lock arm, measure any deviation from target position

2. Loading TestAIM: To determine how much force the arm can withstand while maintaining the set position.

• Applied varying upward loads to see working deflection after locking

• Assessed permanent deflection after force is removed8

Locking Test Results

The average error was found to be:• 1.6±0.43 mm in the

x-direction• 1.15±0.37 mm in the

y-direction• 0.6±0.4 in the z

direction.

Prototype was successful in meeting +/- 2mm accuracy standard.

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Loading Test Results

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Technical Performance Measures

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Cost Analysis

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• Total cost of prototype fabrication was $754.34

• Substantially cheaper than current system (roughly $1 Million)

• Improved manufacturing and producing in bulk could make a device for less than $100

Recommendations– Hardware

• Improve accuracy and reduce cost through optimized manufacturing

– Software• Allow for multiple trajectories to be set by the surgeon• Connect to server and perform tests

– Testing• Increase sample size• Perform Survey of Surgeons• Test in operating room

– Product• File for patent• FDA 510(k) Acceptance

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Conclusions• Successful at creating a functional, two part

image-based guidance system– Software has high data capacity, user-friendliness, and

accessibility– Hardware has a working pneumatic locking

mechanism amenable to operating room• System is close to hoped accuracy

– Errors attributed to manufacturing• Prototype is approved by consulted surgeons• Product is much less expensive than the current

standard

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We would like to thank:• Dr. Scott Banks• Dr. Frank Bova• Dr. Didier Rajon• UF Dept. of

Neurosurgery

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Irene Freire, CSE Samantha Shuhala, ME Emily Churchwell, BME Celeste Rousseau, BE Medhut Alnadi, BME Matthew Thrush, ME

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