Minimally invasive instrument for in vivo measurement of solid organ mechanical impedance

The medical field, and surgeons in particular, are turning to engineers to develop systems that help them learn their craft better. Mannequin-based systems, animal labs and surgery on cadavers each have drawbacks that could be addressed through realistic computer-based surgical simulation systems. To generate a simulation that includes both tactile/haptic and visual feedback, one must know what the material properties of tissue are, so that a finite element or other model can generate the proper predictions for interactions between surgical instruments and tissue. This thesis presents the design, construction, characterization, and use of a mini- mally invasive surgical instrument designed to measure the linear visco-elastic prop- erties of solid organs. The Tissue Material Property Sampling Tool, or TeMPeST 1-D, applies a small amplitude vibration normal to the surface of an organ such as liver or spleen, and records the applied force and displacement. It has a range of motion of up to lmm, and can apply up to 300mN force with a 5mm right circular indenter. The open loop bandwidth of the system is approximately 100Hz, which is greater than the bandwidth of both the human visual and motor control systems. The relationships between indentation force and displacement and material prop- erties such as the elastic modulus of tissue are presented, and models are developed that show the expected response to a standard tissue model. Characterization and calibration tests demonstrate the response of the prototype components. Experi- ments performed on spring and mass elements and on silicone gel samples, which mimic tissue response, show that the TeMPeST 1-D can accurately measure their force-displacement responses.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Ottensmeyer, Mark Peter

Advisor dc:contributor.advisor

• J. Kenneth Salisbury.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8858

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8858