Recurring Meeting of Cleveland Clinic Core Team

Date: June 3, 2014

Time: 10:30 AM EST

Means: In person meeting

Attendees:

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

Agenda:

1. Discuss immediate action items from the last meeting.
2. Revisit joint testing coordinate systems.
3. Revisit anatomical imaging.
4. Discuss tissue testing progress.
5. Decide immediate action items for the next meeting.
6. Other.

Immediate Action Items:

• Jason
  • Finish registration marker error analysis and upload singular value decomposition (SVD) script.
• Tara
  • Provide detailed information on location of accessories and supplies to prepare extensor mechanism of the patellofemoral joint.
• Robb
  • Provide processing tools to move between "right knee abstraction" and "physical representation" of knee data collected during joint testing.
• Snehal
  • Write a Python script to read and plot tissue testing files.
  • Provide Martin Garon (Biomomentum Inc.) ACL data to illustrate the problem in displacement data collection.
  • Fine tune confined/unconfined compression and uniaxial tension protocols by further tissue testing.
• Snehal and Craig
  • Design an image-based thickness measurement system.

Notes:

1. Discuss immediate action items from the last meeting.
   • Jason uploaded the sphere fit algorithms.
   • Jason and Tara updated quadriceps tendon preparation procedure.
     • An image was uploaded of the setup and a description of how to prepare the tendon was added.
     • Tara will provide detailed information on location of accessories to prepare the extensor mechanism.
     • A description of the “tube” or cup used to contain the liquid nitrogen for tendon/clamp freezing during testing should also be added.
   • The lab setup is still ongoing.
     • The eye wash station should be setup this week. The tissue testing machine will be moved to the newa lab after that.
     • Manufacturing of the “tall” bath is still in discussion. There's some back and forth about whether the flat face will be glass or plastic. A decision should be made and documented so that this issue can move forward. Snehal will let Tony Shawan (prototype core manager) that glass is fine and he should finish the bath.
   • Elvis finished his testing last week and Snehal has all his data.
     • Preliminary results were briefly looked at and Snehal is working on a script to parse the data.
       • Essentially, they are very large files for each specific test with results for each loading cycle
         • populated in a serial fashion.
       • Snehal will create a Python script to read/plot the data for review.
       • The raw data was plotted and it is apparent the erroneous displacement data points were populating the results, which makes it difficult to decipher the real response.
       • The force results for a tension test also appear to have a large bandwidth for each loading cycle (around 6 grams), which is greater than the resolution (0.5 grams) of the transducer.
       • This data may be difficult to use.
       • Snehal will test the approach to data collection with a tissue test in the upcoming week(s).
       • Robb theorized there may be electrical noise in the results but this is yet to be determined.
       • Another ligament will be tested, with video included, to troubleshoot these issues.
   • Craig and Snehal worked on the thickness measurement approach using a foam sample.
     • 5 measurements were acquired using the optical approach and the constant pressure LVDT probe.
     • The LVDT measured thinner and both had similar variability (approximately 0.02 mm for 1 mm thickness).
     • The result is approximately a 2% error if the thickness is around 1 mm.
     • Softer tissues may exhibit more variability.
     • A specification for how to handle this measurement during testing needs to be developed.
     • Essentially, a jig to reliably hold the tissue sample and measurement apparatus should be designed and implemented, regardless of whether the optical or LVDT is used. In fact, during the first tests, both measurements may be used for redundancy.
     • A separate system, including a camera, stage, ruler and computer, will be configured for the optical measurement setup. During the upcoming troubleshooting, the heating system should also be included.
2. Revisit joint testing coordinate systems.
   • Robb provided a document covering the convention used to describe the joint coordinate systems, and resulting differences between the right and left knee conventions.
   • The group discussed the general approach and established the sign conventions.
   • It was established that the kinematics are reported in the Grood and Suntay convention whereas the kinetics are reported as the force resulting in the tibia's motion (in it's frame).
   • During the meeting, this was typically referred to as the “physical representation.”
   • The document reflects this but Robb will update the description so that it is clear.
   • Related, a second document will be developed to describe the data in/data out for the processed data to move between the right knee abstraction and physical representation.
3. Revisit anatomical imaging.
   • Ahmet received an spreadsheet of the imaging parameters from Shannon (UH imaging facility).
   • Eventually, this will be used to populate the imaging specifications. Craig will also take a look to ensure it makes sense.
4. Discuss tissue testing progress.
   • This issue was discussed above in the immediate action items.
5. Decide immediate action items for the next meeting.
   • Action items were discussed and agreed on. See Immediate Action Items above.
6. Other.
   • Robb provided an update on the robotics joint testing system upgrades. Dylan is currently replacing the motors.
   • Tara updated the group on the gravity compensation issue of the robotics joint testing system. Apparently the issue is related to the fasteners not being tightened appropriately. The compensation algorithm will be retested for repeatability.