Drill Team Six

Streamlined Intramedullary Nail Fixation for Long Bone Fractures

 

Member profile details

Membership level
2018-2019 Team
Team Name
Drill Team Six
Project Title
Streamlined Intramedullary Nail Fixation for Long Bone Fractures
Design Challenge
People that sustain long bone fractures typically require surgical stabilization using an intramedullary nail implant. One of the major challenges in this procedure involves anchoring the implant using a X-ray to locate a 5mm diameter screw hole in the implanted nail for securing the nail in place with a screw. This challenge requires a high level of accuracy which can be quite frustrating for those performing the procedure. By developing a streamlined mechanism for fixation of the nail that does not rely on X-rays or tedious precision technique, surgeons and hospitals will benefit from the reduced time sick trauma patients must remain under anesthesia, decreased time spent in the operating room, and minimized X-ray radiation exposure to patient and medical surgical staff.
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Design Summary
Our design objective is to create a device that is accurate, low cost, reduces operation time and x-ray exposure, is easy to use, and fits well with the current intramedullary rod fixation workflow. With this objective in mind, constraints on our design solutions include making sure the rod is stable at the end of the procedure, adaptability to varying intramedullary rod specifications, and the device should not cause any unnecessary harm to the patient. Our approach to solving this challenge has consisted of understanding the problem, researching current techniques, concept generation, concept evaluation, and witnessing the intramedullary rod fixation procedure firsthand. We have made a proof of concept prototype that adheres to our design criteria/constraints. This prototype consists of a brace that moves in three degrees of freedom (translational, rotational, and angular) and has a magnetic sensor used to find the location of a magnet placed in the distal hole location of the rod. The magnet is placed in the distal hole location before the rod is hammered into the bone along a magnetizable guidewire. The magnetic sensor device is located in a sensor holder on the brace within the rotational degree of freedom slider. The magnetic sensor sends a voltage based on the magnetic strength field to a signal acquisition software such as LabVIEW. Once the signal is acquired in LabVIEW, further signal processing is done to isolate the peak/ trough voltage for each degree of freedom as a calibration step. This peak/trough correlates to the magnet location, which is in the distal hole location of the rod. Following the calibration step, the surgeon can align each degree of freedom using a graphical user interface that includes a green LED and lights up when each degree of freedom has been aligned. After aligning each degree of freedom, the user can use a set screw to fixate that degree of freedom. Once each degree of freedom has been aligned, the magnetic sensor attachment can be replaced with a drill attachment to allow the surgeon to create a path for drilling a pilot hole. Prior to drilling, the magnet can be removed by pulling out the guidewire from outside the body. Following this, a pilot hole can be drilled to fixate the nail. A final x-ray can be taken to ensure proper fixation of the rod to the bone. Next steps in this project include optimizing the angular degree of freedom location algorithm, optimizing the calibration process, add visual feedback to the actual brace instead of having the user rely only on the graphical user interface, and wireless integration to remove any noise that could be present due to the current DB9 connection we are using to power the magnetoresistive sensor/ transmit its electrical signal to LabVIEW.

Last Updated: 04/28/2019
Date Updated
Sunday, April 28, 2019
Sponsors
Chuck and Sharon Fox
Department(s)
  • Bioengineering
  • Mechanical Engineering
Faculty Advisor 1 - Name
Sabia Abidi
Faculty Advisor 1 - Department
  • BIOE
Client First Name
Ashvin
Client Last Name
Dewan
Client Company/Organization
Houston Methodist
Award(s) and Recognition
Winner of the top prize of the Excellence in Engineering award at the 2019 Engineering Design Showcase at Rice University.
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