Physician-Inspired Medical
Device Solutions
With the goal of engaging graduate students
and accelerating ideas into prototypes, teams of MIT graduate students in
Electrical Engineering and Mechanical Engineering spend a semester
collaborating with clinicians in CIMIT-affiliated hospitals to develop
innovative medical devices. Clinicians (physicians, nurses, and scientists)
present clinical problems and initial ideas on how they might be solved.
Students form teams to work with the clinicians to turn these ideas into
reality. The goal is for the students to deliver a working prototype and a
journal-quality article in one semester. The course has been a great
opportunity for clinicians to test out new ideas and to stimulate new
collaborations. For example, Robopsy, a robotic device to assist radiologists
performing tumor biopsies was invented by an MIT team led by Rajiv Gupta, MD,
in 2004. The team has been awarded the 2007 MIT $100K prize, the world's
leading entrepreneurship competition.
Moderator: Rajiv Gupta, MD,
Resident, Radiology,
Physician/Student Teams:
A need
exists to accurately monitor hydration in human beings. Water regulation in humans involves
osmoreceptors in the brain as well as baroreceptors in the large blood
vessels. These receptors send signals to
the brain to control the release of vasopressin, also known as antidiuretic hormone
(ADH), from the posterior pituitary.
Decreased fluid intake results in increased vasopressin and decreased
urine volume. Increased fluid intake
results in decreased vasopressin and increased urine volume. These regulatory mechanisms can fail in
disease states such as diabetes insipidus where vasopressin is not produced or
in SIADH (syndrome of inappropriate antidiuretic hormone) where ADH is produced
to excess. Other disorders of water
regulation occur when there is inadequate water intake due to inadequate thirst
mechanisms or the inability to drink independently, resulting in the risk of
hyponatremia or hypernatremia with over-hydration or under-hydration. Water regulation problems may be found in the
elderly and infirm, infants, patients receiving intravenous fluids, patients
receiving nutrition via gastrostomy or jejunostomy tubes, and athletes
(especially long-distance runners exerting themselves).
Graduate students at MIT
have developed a non-invasive method for electronic monitoring of hydration,
using radio frequency energy from 100kHz to 10 MHz to measure the loss tangent
of the frontalis muscle, which is located in the forehead. The frontalis muscle was chosen because of
its large surface area and its high level of vascularization. The loss tangent, a function of electrical
conductivity and permittivity, reflects the muscle’s osmolality and thus its
hydration status. It is independent of
sensor electrode geometry. Using a
four-electrode configuration, the students’ device measured the impedance of
the frontalis muscle and calculated the loss tangent. The loss tangent of the frontalis muscle is
an indicator of the muscle’s hydration level, and measuring the loss tangent
provides a method for non-invasively monitoring human hydration.
Catheter-based Device for Intra-Cardiac
Mitral Valve Chord Manipulation
Physician: Robert Levine, MD, Professor of
Medicine, Harvard Medical School, Massachusetts General Hospital,
rlevine@partners.org
Team: Will Boswort, Ani Mazumdar, Miguel
Saez and Alex Slocum, Jr.
Mitral
valve regurgitation is problem that
affects around 450,000 people in the
Students from MIT are
developing a special catheter to perform chordal cutting percutaneously. They have attempted to produce a catheter
that could be fed into the left ventricle through the femoral artery and the
aorta. Their envisioned procedure
involves gripping the chord to be cut with the end of the catheter, using
ultrasonic imaging to make sure that the correct chord was being gripped, and
then cutting the chord. Further testing
remains to be done, but their device may someday provide cardiologists with a
minimally invasive way of treating mitral valve regurgitation.
Presentation
not available
Transfascial
Hernia Fixation Device
Physician: Ali Tavakkoli-zadeh, MD, Instructor
in Surgery,
Team: Megan Roberts, Michael Eilenberg,
Jessica Galie, Rajiv Gupta, Martin Culpepper
The abnormal protrusion of an organ through
a wall supposed to contain it is referred to as a hernia. Hernias can occur anywhere, and most require
surgical repair to alleviate pain and to prevent life-threatening
complications. A ventral hernia refers
to a case in which the intestine protrudes through the middle of the abdominal
wall. Around one hundred thousand
ventral hernias are treated each year, either via open surgery or via
laparoscopic surgery. The latter is less
invasive and seems to be the most effective treatment strategy. In the laparoscopic procedure, small
incisions are made and a mesh is fixed over the breach in the abdominal muscles
to prevent any organs from protruding.
The mesh can be tacked to the abdominal wall, but the tacks sometimes
work loose and allow the hernia to return.
Transfascial sutures can also be used, but these can be difficult to
place laparoscopically and can cause significant post-operative pain. Students from MIT are exploring a new
technique that uses anchors to hold the mesh in place. The anchors are placed above the fascial layer
and below the adipose tissue, and they are compatible with most sutures. The anchors have yet to be perfected and are
not ready to be tested in humans, but the students have number of ideas to
improve their design and their materials.
Presentation not available