Ultrasound Imaging and Treatment of Hernia Mesh

There is a critical need to develop a new device to noninvasively treat mesh infections without removing the
mesh. In the absence of such a device, the treatment of many mesh infections will remain highly invasive and
costly. This study's objective is to develop cavitation-based histotripsy to treat surgical mesh infections.
Histotripsy generates/excites a cloud of micron sized bubbles in the tissue which mechanically shred the targeted
cells. The physics of microbubble collapse promotes lysis of bacteria attached to the implant enhancing the
destruction of the bacteria biofilm causing the infection.
Specific Aim #1: Improve pulsing scheme to reduce the impact of cavitation memory. We hypothesize that
adding lower amplitude pulses will reduce cavitation memory in our application as well drastically reducing
treatment times. The impact of the exposures on mesh properties will also be determined for the different
exposure conditions.
Specific Aim #2: Improve mesh Contrast. We hypothesize that it will be easier to visualize the mesh if we
combine shear-wave and pulse echo imaging and/or increase mesh contrast by adding glass microspheres to
the polypropylene fibers. Increasing the contrast may also increase the effectiveness of our therapy by providing
a stronger reflection off the mesh increasing the pressure fields in the immediate vicinity of the mesh.
Specific Aim #3: Test therapies safety and effectiveness in an animal model. We hypothesize that our
therapy will be able to treat bacteria biofilms on hernia mesh safely and effectively in an animal model. This
hypothesis will be evaluated by implanting infected mesh samples in a swine model at varying implant locations
and depths while also carefully assessing the tissue for any unintended damage.
This project is significant because once developed thousands of patients each year would have an alternative
to invasive surgery for treating mesh infections. In addition, improving mesh contrast could improve patient care
even when no infection develops. Once feasibility has been shown for mesh infections, numerous other
implanted devices may be candidates for our same histotripsy-based treatment.

Grant Number: 5R01EB033359-03
NIH Institute/Center: NIH
Principal Investigator: Timothy Bigelow