Week 6 - Brandon

Last week marked the first milestone of two of the three projects that I have been working on. First, I have been doing research into cracking joints; why they happen and any implications. Interest in this had come about during clinical interactions with patients. After searching the literature, I had come up with a few causes for the cracking and what science has been done to explore this phenomena thus far. Dr. Härtl requested that I present my findings in lab that week, which I did. It was a fairly long presentation in which I outlined the causes in general and then specifically into the "cavitation" experienced at the synovial joints. Physical experiments done around this cavitation in conjunction with joint cracking is very scarce, which is why there does not seem to be a concrete link between joint cracking and oestoarthritis. I am continuing the search for information regarding this topic and possibly looking into writing a type of review on the subject.

The second project, measuring intradiscal pressure in the caudal intervertebral discs of rats hit a major obstacle. We obtained a blood pressure monitor from the biomedical engineering dept at the hospital that we hoped to use in conjunction with a transducer and high gauge needle to measure the pressure in a few of our rat tail samples. Everything hooked up smoothly and we were able to obtain an initial reading of a pressure value (we think). However this value did not change, and slowly when it did, when we began to manipulate the tail. We thought that it was a problem with how responsive the transducer is, but the system is used to measure arterial pressure which is fairly dynamic. With this system now working we are looking at alternatives including collaboration with another lab that has the capability of measuring intradiscal pressures in human cadaveric models. The transducer in this case may be too large for our purposes. There is a smaller fiber optic sensor that would be useful, but it is quite expensive. Still it may be worth looking into negotiating a type of trial use period.

The third project, MRI vs XRAY in quantifying disc height changes, is moving along nicely. Measuring each image takes some time, but it is fairly easy and an interesting study. We are still missing a few of the most recent scans which would be extremely helpful in getting a time dependant look at how each imaging modality estimates the disc height changes; crucial information when it comes degeneration of discs and accurately studying this phenomenon. Conclusion of this study will also aid us in moving forward with our degeneration and replacement studies.

During the week I visited both the clinic and the OR. The cases were pretty familiar by now, mostly decompression diagnoses. I found it interesting that the same compression of the spinal cord could be brought on by so many different things ( i.e. thickening of the ligaments in the spinal canal, herniated discs, tumor, cysts). There is a very mechanical nature about pain associated with the spine, and it seems that one can only go so far with chemical treatments before mechanical intervention is needed. I also saw an open heart surgery in which two heart valves were replaced and another repaired. It was a bit weird not hearing the rhythmic beep of the monitor when I walked into the room. The surgery itself was quite interesting to watch, and a had a great view on a standing stool at the head of the table. Putting the valves in was fairly quick, most of the time was spent reviving and making sure everything was working properly again.