Sunday, June 27, 2010

Week 2 - Ruiz

Unforeseen challenges in a left popliteal artery aneurysm repair

With the permission of Dr. Bush, one of the Cornell surgeons, I was able to observe a highly invasive aneurysm repair procedure in the lower left leg of a patient. From the very beginning I knew that this surgery was markedly different than the surgeries I had viewed last week. The patient was male, in his 70s, and had previously undergone a popliteal bypass in his right leg – which, unfortunately, had resulted in skin and vasculature failure in his upper right thigh, leaving a deep recession/cavity in that area. This man had other complicating factors as well – he was allergic to penicillin, had some form of sleep apnea, and he had extremely small arteries that may have been weakened (from the previous bypass) and partially thrombosed (due to age and lifestyle habits). While the sleep apnea made him hard to intubate, the real problem surfaced when the anesthesiologist tried to put in a central line in his arm. After multiple sticks by the residents and the anesthesiologists, a trained technician was called in to perform real-time Ultrasonic Doppler flow detection to help locate the small and deeply recessed arteries. Finally, after simultaneously scanning the arm of the patient with Ultrasonic Doppler while another anesthesiologist stuck the arm with a needle, they were able to get the central line in! What should have been a routine procedure turned out to be quite complicated, and I was impressed at how quickly the problem was solved when incorporating the real-time ultrasound technology.

Even so, I had some questions brewing in my head after watching the 90minute-long process. Why is the Ultrasonic Doppler a last resort? From what I understand it is fairly non-invasive, and it could have saved a lot of time and trouble had they pulled out the device immediately after the patient was put under. I was also wondering why the Doppler device was built into a wand sort of format, with the detecting probe at the head. I noticed that the technician had trouble keeping the wand/head in the correct plane to monitor blood flow in the arteries. I wonder how the device could be modified to either 1) facilitate proper orientation (and stabilization after proper orientation is found) for blood flow detection, and 2) enable the device to orient itself without the manual manipulation of the technician.

That said, the aneurysm repair was more complicated than I thought it would be. Two angiograms had to be performed so that Dr. Bush could verify that there was still blood flow in the leg below the site of the aneurysm. If there had been stagnant flow, the surgery would have been called off. It turned out that even getting the proper image from the angiogram was a challenge. The first angiogram did not prove successful because the injected dye could not reach down far enough to image the area below the aneurysm site. Thus, an injecting catheter had to be threaded down into the aneurysm (literally, which is quite dangerous if the aneurysm breaks up and causes clotting elsewhere in the body) so enough dye could be injected into the entirety of the vessel for proper imaging. I don’t believe there was any way to get around it since the angiogram was essential for planning the next steps in the surgery. I do wonder though: is there a better way to provide enough imaging dye for the angiogram without risking breaking or rupturing the aneurysm? Perhaps the intrinsic flow properties of the dye could be modified, or the image-taking protocol for the angiogram could be changed.

Bone-anchored hearing aid (first stage implant) with cartilage graft ear reconstruction

Dr. Grant was able to introduce me to fellow Columbia surgeons and residents in Plastic Surgery, and through some of them I was able to see a really interesting surgery at the Children’s Hospital. This surgery was two-part: part 1 involved the first stage of a hearing aid implant procedure, and part 2 involved harvesting cartilage from the rib of the same child to use for reconstructing an ear for this child. From what I understand, this child had been born with a malformed right ear which had no cochlea. This invasive procedure was delayed until the child reached 12 years of age because during the child’s early development there was no telling how the cartilage-grafted ear would respond or adapt to the growing child.

Overall, this dual-part procedure was extreme in a couple of ways. The first stage ear implant required that screws be drilled into the child’s skull. A very small incision was made on the right posterior region of the head, and after the muscles and tissue were pulled/cut away to expose the skull, a drill (yes, it even looked somewhat like a power tool) was used to insert two ear implant screw attachments into the skull. Surgeries of this kind are difficult to perform on children because child skulls are not as hard and are not as thick as adult skulls – thus, it is hard to stabilize the screws in the skull for the long-term. An impressive detail in this surgery was the tool used for drilling into the skull – it actually was programmed to stop on its own when it passed through the entire skull layer. It is critical to stop the drill before it breaks through the basal layer of the skull and starts to pierce and damage the brain tissue. The cranial drill was a great solution to the problem of surgeons not being able to predict exactly when they would break through the skull layer. I did noticed that the surgeons had trouble keeping the drill perpendicular to the skull surface though – perhaps other skull surface sensors and device positioning mechanisms could be incorporated into this cranial drill to make it even more efficient.

The other extreme part of this surgery was the harvesting of cartilage from the lower rib region of the child. I was shocked that the surgical tools being used were quite large and forceful. (Apparently harvesting cartilage is not as easy as cutting through muscle or tissue!) I quickly learned that cutting out cartilage involves methodical slicing at the proper angle and with precision so as not to take too much or too little out of the rib section. Unfortunately I was not able to see the entire ear reconstruction procedure, but I did see the early stage of the cartilage re-structuring. I am very impressed how the surgeon (Dr. Wu) could start with a mere piece of cartilage and build a full new ear for the child! I only wonder though, could a synthetic ear have been tissue engineered for this child? I am not sure if tissue engineering has reached a stage through which this can be done, but I do believe that a fully tissue engineered cartilage ear construct would have saved a lot of pain and stress during recovery for the child because the cartilage-rib-harvesting is more painful and takes longer to recover from than the new skull screw implants.

Additional noteworthy surgeries and meetings

I was able to see a diverse set of surgeries this week. In addition to the aneurysm repair and the ear reconstruction, I observed: a primary elected caesarean section, nipple-sparing mastectomy, bilateral breast reduction, and a unilateral second-stage breast augmentation. All were performed on different female patients of different ages ranging from 29 to early 60s. It was interesting to see how the patient’s age and physical health would impact what strategies Dr. Grant would employ in the surgery.

I also had the unique chance to meet with consulting representatives from a company named Allergan. The two representatives were observing a few of Dr. Grant’s surgeries to see how the Allergan products (i.e. synthetic breast implants and expanders) were being implemented for different patients in a hospital environment. It was great talking to them because I was able to ask them questions about how they chose particular implant designs and materials over others and how they distributed their product to different client hospitals with different needs. Additionally, the Allergan reps were questioning Dr. Grant and his plastic surgery residents to see what current issues they had with the Allergan products, and to inquire how the products could be made better or more customizable for different patients. This encounter further proved to me that there are many close-knit ties between technology/industry (i.e. marketing, development, and engineering of medical products and devices) and the clinic/hospital application of said technology. Crossover is essential in this type of relationship, especially since feedback from both sides can directly improve patient care and satisfaction for hundreds of patients all over the world.

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