Open Access
Mccracken, Eric Douglas
Area of Honors:
Mechanical Engineering
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Jason Zachary Moore, Thesis Supervisor
  • Daniel Humberto Cortes Correales, Honors Advisor
  • scalpel
  • scalpel cutting
  • compliance
  • vibration
  • cutting forces
This thesis for Schreyer’s Honors College investigated the concept of using compliant vibrational tools for medical soft tissue cutting. Ultrasonic vibrations were applied to scalpels that had different compliant hinge geometries incorporated into the handle. The hypothesis of the thesis was if a compliant vibrational cutting tool was used, the amount of force required to make cuts will be reduced. Tissue deflection caused by the scalpel blade would be reduced if the force required to make the incision was reduced. When the deflection of the tissue is minimized, higher cutting accuracy and precision is possible. Having higher cutting and precision would benefit many different surgical procedures especially any invasive surgeries. The objective of this thesis was to determine if the cutting forces could be reduced if a compliant hinge was added to the handle of a scalpel along with added ultrasonic vibration. The first task in achieving the objective was to design a compliant hinge geometry for the scalpel handles. Designs used in past experiments involving adding compliant geometry to needles were incorporated into the scalpel handle design. After the compliant geometry for the scalpel handle was designed, all the experimental mounting components and scalpel handles were fabricated. Using the fabricated components, vibrational cutting experiments were performed. Three different scalpel geometries were tested: no compliant hinge, single compliant hinge, and a double compliant hinge. Each geometry was tested with vibration added and no vibration added. Experiments were completed by cutting phantom gel which was used to resemble soft tissue. Cutting force and cutting depth were the parameters that were analyzed. After the experiments were ran there was evidence that initial incision forces were reduced by between 17% to 42% when vibrations were added to a scalpel. The different compliant geometries led to different amounts of force reductions during the initial cutting with the double compliant hinge scalpel handle having the largest reduction. The force reduction of a scalpel handle with no compliant geometry with added vibration was only 17.06%. The force reduction of a scalpel handle with a single compliant hinge with added vibration was 39.26% and a handle with a double compliant hinge had a 41% reduction. After the initial incision was made, the added vibration and compliant geometry no longer had any effect on force reduction.