This document describes the development of an image-guided surgical system for intracranial neurosurgery. It includes a web-based software for surgical planning and a mechanical arm to position surgical probes. The software allows uploading of MRI/CT scans and viewing the target in 3D. The articulating arm has 5 degrees of freedom, maintains sterility, and locks probes with sub-2mm accuracy. Testing showed the prototype meets accuracy standards and is substantially cheaper than current methods, with potential to further reduce costs through optimized manufacturing. The system was approved by consulted neurosurgeons.

1. Image Guided
System for
Intracranial
Neurosurgery 1

2. 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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3. 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
3

4. 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
4

5. 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
5

6. Hardware Design Overview
“Dumbbell” design
• 5” rigid shaft
• Ball joints
• Cylinder enclosures
Pneumatic locking
mechanism
• Passively locks
• Air pressure supplied
w/ foot pedal
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7. 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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8. 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 Test
AIM: 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 removed 8

9. 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.
9

10. Loading Test Results
10

11. Technical Performance Measures
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12. Cost Analysis
12
• 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

13. 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 13

14. 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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15. We would like to
thank:
• Dr. Scott Banks
• Dr. Frank Bova
• Dr. Didier Rajon
• UF Dept. of
Neurosurgery
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16. Irene Freire, CSE
Samantha Shuhala, ME
Emily Churchwell, BME
Celeste Rousseau, BE
Medhut Alnadi, BME
Matthew Thrush, ME
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