Recurring Meeting of Cleveland Clinic Core Team

Date: May 20, 2014

Time: 10:30 AM EST

Means: In person meeting

Attendees:

1. Ahmet Erdemir
2. Jason Halloran
3. Craig Bennetts
4. Snehal Chokhandre
5. Elvis Danso
6. Robb Colbrunn
7. Tara Bonner

Agenda:

1. Discuss immediate action items from the last meeting.
2. Review of specimen preparation specifications.
3. Discuss tissue testing progress.
4. Decide immediate action items for the next meeting.
5. Other.

Immediate Action Items:

• Jason
  • Outline details of patella marker registration and provide scripts for registration in the utility folders of source code repository.
  • Modify extensor mechanism preparation images in the specimen preparation page.
• Snehal
  • Rewrite harvesting tissue section of specimen preparation based on her recent experience.
  • Use the vibratome to prepare cartilage and meniscus tensile test samples to evaluate tissue preparation.
  • Conduct thickness measurements using a rubber band as a test problem.
• Tara
  • Add relevant images and update existing ones in the specimen preparation page to reflect latest changes in robotics testing.
• Craig
  • Complete post-processing test problem for cloud computing prototype.

Notes:

1. Discuss immediate action items from the last meeting.
   • Jason summarized results from the patella registration, including comparisons.
   • Snehal summarized the tissue testing lab setup.
     • Besides installing the eye wash station, the setup is nearly complete.
     • After cleaning, the equipment can be moved to the new space.
     • Regarding fixtures for tissue testing, Snehal reported that the old clamps are still being used for tensile testing, the tall bath is being made (the short is currently being used).
     • Tony Shawan (prototype core) will provide an estimate for the new clamps for tensile testing.
     • Elvis's tensile tests will need to start this week in order to finish before his departure.
     • The rest of the fixtures are made. An acrylic base fixture for confined compression has been made.

   • Snehal has talked with Martin (at BioMomentum) about the apparent negative numbers during tensile testing.

     • He says it may be a sampling problem but will explore this behavior and report back.
     • Regarding sampling, the experimental results can be down sampled by skipping steps, and possibly only during relaxation portion of the testing.
     • The stress relaxation test can be broken up so that the instantaneous response is sampled at the highest possible frequency.
     • Video recording will also need to be down sampled or the file size will be unmanageable (approximately 250 gigabytes if sampled at 640 by 480 pixels and 10 hz).
     • Discussion centered around how to resample the video data to capture the appropriate response.
     • Options include higher sampling rate during the instantaneous loading followed by a lower sampling rate during relaxation.
     • Note, time stamps are used to align the transducer and video samples.
   • Snehal made some changes to the tissue preparation specifications.
     • The tissue harvesting section will be rewritten based on the most recent testing sessions with Elvis.
     • Snehal has developed a sequence and this will be reflected in the description. Sample preparation is adequate.
     • A description for preparation of cartilage tensile samples will be added.
     • All procedures will be completed for tissue preparation this week by Snehal.
     • Regarding specimen preparation in general, Jason will update the patella registration images and description.
     • Tara will update description of the new Optotrak probe.

   • Snehal also updated the specifications for Experimention TissueMechanics page to include all the tissue types and the primary outcomes.

     • Ahmet would like Snehal to provide an abstraction of the various loading sequences that will be used during the testing.
     • These graphs could be generated in Inkscape to reflect the desired time-loading (displacement) graphs.
     • Loading rates of 100%/second will be attempted though this will be evaluated in terms of necessity for tissue response (is a high frequency response) and capability of the machine (e.g. potential overshoot at higher loading rates).
     • Confined and unconfined testing of cartilage and meniscus will be attempted.
   • Secondary tissue tests will be populated if needed but as of now, the first knee(s) will focus on the primary restraining tissues. Specifications will need to be provided before tissue harvesting if it is decided additional tissue types will be tested.
   • Snehal also tested two different approaches to quantify thickness measurements (optical and constant pressure LVDT). Results are summarized on the wiki. To summarize, inconsistent results were found between the two methods for two different tissue samples.
   • Craig will provide a post-processing test problem for the meeting with Stanford tomorrow.
   • Robb and Jason met to discuss/test the approach to pressure calibration of the Tekscan pressure sensor.
     • An approach was summarized on the wiki but the actual geometry of the specimens used for calibration needs to be decided on.
     • It was decided that a candidate “foam” material with a similar indentation stiffness as cartilage will be cut into an appropriately sized dome (e.g. half sphere) and thickness to provide an approximate approach to calibration.

2. Review of specimen preparation specifications

• See above for the discussion regarding this item.

3. Discuss tissue testing progressing

• See above for the summary of this item.

4. Decide immediate action items for the next meeting

• Immediate action items were discussed and agreed on.

5. Other

• Craig, Jason and Ahmet met about filling in the specifications of modeling.
  • Craig summarized the potential hierarchical approach to defining the modeling workflow/assembly.
  • This is a strategy to abstract the connections between modeling components and the required relationship(s) between these pieces.
  • Using this, individual components or the desired assembly (up to the whole model) could be developed with the appropriate input/output(s).
  • Craig will summarize this on the wiki.
• Ahmet had the engineering advisory board meeting yesterday.
  • The committee thought the approach was “good.”
  • Ahmet would like to establish open collaboration with outside groups and Yasin suggested setting up internships with specific labs.
  • Both Open Knees and the collaborative group would benefit.