John Yu

1
Ischemia Sensing Smart Organ Retractor__________
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_________Project Checkpoint

• John Yu
• Jen Horwat
• Sunipa Saha
• Mentors
• Greg Fischer,
• Mark A.Talamini, MD

MISTC Lab, Johns Hopkins Hospital03/31/05
2
Overview

• Problem Detection of ischemia intraoperatively
• Studies show that intraoperative retraction can
  produce ischemia in the affected tissue
• Solution The Smart Organ Retractor
• Placement of force and ischemia sensors to allow
  measurement of force and ischemia in the tissue
  over time

3
System Diagram
4
Proposed Deliverables

• Manual Retractor
• Obtain better components
• Preliminary calibration
• Place force sensors on a manual retractor
• Experiments
• DaVinci Retractor
• Pattern of sensors
• Pattern or grid of multiple sensors
• Visual display of the pattern
• Calibration

5
Updated Deliverables

• Manual Retractor
• Obtain better components
• Preliminary calibration
• Place sensors on a manual retractor
• Experiments
• DaVinci Retractor
• Pattern of sensors
• Pattern or grid of multiple sensors
• Visual display of the pattern
• Calibration

6
Laparoscopic Retractor
Smart Organ Retractor, 04/07/05Laparoscopic
Retractor Courtesy of Dr. Marohn
Smart Organ Retractor, 04/07/05 Laparoscopic
Retractor Courtesy of Dr. Marohn
7
Updated Deliverables

• Manual Retractor
• Create new manual retractor
• Manufacture new retractor sheaths with sensors
• Obtain force readings from retractor
• Obtain better components
• Preliminary calibration
• Force and oxygen sensors on a manual retractor
• Experiments at MISTC
• Obtain several data sets for analysis with manual
  retractor

8
Updated Deliverables

• Laparoscopic Retractor
• Modify 5-fingered fan laparoscopic tool
• Place ischemia sensors and strain gauges on tool
• Experiments at MISTC measuring ischemia occurring
  at different retraction forces for varying time
  periods
• Pattern of sensors
• Grid on laparoscopic tool, not manual retractor
• New controller and updated program
• Calibration
• Full calibration

9
Work to Date

• Component Testing
• Retractor Design and Manufacture
• Sheath Design and Manufacture
• Experiments with Manual Retractor
• Data Obtained
• Laparoscopic Design

10
Component Testing
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Retractor Design

• Mimics the Balfour Retractor

www.faico.com.ar/separadores.htm
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Retractor Design

• Original design
• Metal handle with a slot for attachment to
  Balfour retractor

Smart Organ Retractor, 03/24/05

• Large Sheath

Smart Organ Retractor, 03/24/05
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Retractor Design
MISTC Lab, Johns Hopkins Hospital, 03/24/05
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Retractor Design

• Modified design
• Thinner handle sheath

MISTC Lab, Johns Hopkins Hospital, 03/31/05
Smart Organ Retractor, 03/30/05
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Sheath Design

• Original Design
• Horizontal placement of photodiode and LED
• Modified Design
• Vertical placementof photodiode and LED
• Smaller
• Grooves for wiring

Smart Organ Retractor 03/30/05
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Experimental Setup
InteractiveGUI
Controller
Balfour Manual Retractor
ForceAmplifier
MISTC Lab, Johns Hopkins Hospital, 03/31/05
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Data Obtained
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Data Obtained
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Data Obtained
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Laparoscopic Design

• Remove two of the fingers on a standard 10mm ?
  five finger laparoscopic retractor
• Apply strain gauges to center finger
• Apply photodiode and 2 LEDs to the remaining
  three fingers

Smart Organ Retractor, 04/07/05Laparoscopic
Retractor Courtesy of Dr. Marohn
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Problems and Dependencies

• Obtaining Components
• bicolor LEDs
• appropriately sized LEDs and photodiodes
• Size of retractor and sheaths necessary adapted
  for pig liver
• Epoxy
• Access to MISTC center and pigs
• Subject health and access to liver

22
Proposed Schedule

• March
• Program PIC
• Preliminary Calibration
• Consistent readings
• Force sensors on manual and daVinci retractors
• Mid-March
• Preliminary experiments
• Ischemia sensors on manual and daVinci
  retractors
• April
• More experiments with manual retractor

23
Proposed Schedule

• Mid-April
• Modifications to manual retractor
• Sensor pattern on manual retractor
• Experiments with daVinci retractor
• May
• Complete minimum and medium deliverables
• Preliminary experiments with patterned retractor

24
Revised Schedule

• March
• Create manual retractor
• Program PIC
• Preliminary Calibration
• Consistent readings
• Force sensors on manual and daVinci retractors
• Mid-March
• Create retractor sheaths and place sensors
• Preliminary experiments
• Ischemia sensors on manual and daVinci retractors
• April
• Further experiments with manual retractor
• Modifications to manual retractor and sheaths
• User-friend GUI

25
Revised Schedule

• Mid-April
• Modifications to manual retractor
• Sensor pattern on manual retractor
• Experiments with daVinci retractor
• Design and test laparoscopic tool
• Build new controller to include strain gauges
• Experiments with laparoscopic tool
• May
• Complete minimum and medium deliverables

26
Next Steps

• Finish putting gauges on laparoscopic tool
• Build new board for laparoscopic tool
• Test laparoscopic tool
• Continue running experiments with manual
  retractor

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Smart Organ Retractor
MISTC Lab, Johns Hopkins Hospital04/07/05
MISTC Lab, Johns Hopkins Hospital04/07/05