Week 6

07-20-2018

The second to last week here in NYC seemed to pass by faster than the previous ones. I continued to practice surgical techniques to prepare for the upcoming live animal practice and devoted a great chunk of my time on getting the paperwork and clearance done for Heidi’s (my advisor, who will be visiting the lab and learning the open ACLT with me) visit next week. In this week’s training, one thing that I found interesting is one suturing method called the mattress stitch. It is commonly used on skin, particularly lose skin. Rodents have much looser skins than humans as a protection from predators, and the skins in their abdomens and legs are especially so. Thus, with a simple stitch, sometime the outer side of the skin will come in contact at the seam, preventing it from healing. The mattress stitch uses the far-far, near-near system. The far-far suture placement passes 4 to 8 mm from the wound edge, deep in the wound below the dermis. The near-near placement occurs at a shallow depth (about 1 mm) and should be in the upper dermis. The near-near placement should be within 1 to 2 mm of the wound edge. [1] This technique permits greater closure strength and better distribution of wound tension.

While shadowing Dr. Rodeo in out-patient clinic, we discussed how different the symptoms manifests despite of similar X-ray and MR imaging readings. Sometimes on the X-ray and MR imaging, the physician would expect the patients to be great pain and could barely move, however, when in reality the patients not only were experiencing tolerable pain but could also participate in moderate exercise/activities or sometime even extreme sports (like the lady I mentioned in last week’s blog, I am still having trouble believing that she actually walked into the clinic by herself). Aside from its clinic implication----that there are some more complicated changes in soft tissue, tendon and nerves in OA independent of the pathological changes in cartilage, these cases made me think how I could design my animal studies to more faithfuly assess the progression of OA in rodents. The current golden standards of assessing OA developments across animal models are X-ray and MR imaging and histological readings. Histological reading are end-point assessments that cannot be used to monitor the progression of OA in the same animal.  X-ray and MR imaging, as mentioned above, may not reflect the true progression of OA. I now believe, in addition to microCT imaging during the study and histological scoring after tissue harvesting, behavioral and functional testing should be included in the rodent student to assess OA development, and eventually as parameters to test the efficacy of our lubricin supplements. So far motion and gait analysis, rotor rod, and pain assessments with heat pad or Von Frey apparatus are on the list to be considered.  

[1] https://www.aafp.org/afp/2002/1215/p2231.html

Figure. Interrupted vertical mattress stitch