Week 3: Understanding Device Modification
Hello again!
This week I met with Bryan R. to talk about the process of device modification and why it is necessary with Physician Modified Endografts (PMEGs). Device modification is not condoned, but physicians will opt to do it if necessary.
There is always going to be a reason for a physician to modify a device. Usually, it is one of two reasons:
- The device does not fit the anatomy of the patient for what is being treated. The device may end before the area that needs treated ends. There are many reasons that a device may not fit anatomy. Every anatomy is different, and every patient is unique. For example, there is quite a bit of variation surrounding the distance and location of where vessels begin and end.
- The physician does not want to cover too many vessels. When using a device that covers more than the necessary area, the branching vessels, including intercostal vessels that lead to the spine, are covered as well, leading to a shortage of blood supply to those areas. If too many vessels are covered, the risk of paraplegia increases. In turn, physicians only want to cover what is needed.
From there, Bryan walked me through the steps of device modification, presenting different fluoro-images and x-rays. Unfortunately, I cannot show them here, but the images presented different cases of device modification and why it was necessary in each case to treat the patients.
When modifying the device, physicians contact the companies for guidance on what can and cannot be done to treat the patient. After discussing the options and deciding on what to alter, the device is set up for modification.
Instead of opening the entire device, the device is opened to the end of what is being modified, secured by a slipknot and needle to stop deployment. Once open, the patient’s CT scan is referenced to decide where to put the modifications.
With PMEGs, there are often two types of modifications:
- Fenestrations: holes in the devices. Fenestrations must be lined up perfectly in the patient in order to work.
- Portals: inner branches. Portals can be maneuvered to fit properly in the branches and are easier to move around. These are very universal.
After altering the device, wires are run through each fenestration and portal to align the device within the patient, and the shipping sheath is put back on to shrink down the device.
It was fascinating to meet with Bryan and go in depth on device modification. It definitely displays how device modification and off-label use are necessary at times to treat the patient and why it is done so often. Going into the next week, I will be setting up and meeting with physicians who can shed more light on their experience with the Physician Sponsored Investigational Device (PSIDE) process. I will also continue researching the PSIDE requirements and process.
Thank you for reading!