Date of Completion

8-24-2015

Embargo Period

8-21-2025

Advisors

Kenneth Horton; Marie Luby

Field of Study

Biomedical Engineering

Degree

Master of Science

Open Access

Campus Access

Abstract

Since introduction in the early 20th century, laparoscopic surgery has become common practice for a variety of procedures and is credited for reducing patient trauma and decreasing healing time. To accomplish intracorporeal operation, chest cavities of patients are insufflated and specific, unique hand tools are required in order to accomplish a variety of complex surgical tasks. While the development of task specific tools has increased dramatically in recent decades, it has been outpaced by the increasing anthropometric diversity of medical professionals. In general, it is extremely common for only select anthropometries to be considered during the design and development of hand tools, which creates potential ergonomic risks for individuals with incompatible anthropometric dimensions.

The purpose of this design thesis was to identify and evaluate a currently existing laparoscopic hand tool and then redesign it to increase usability and reduce ergonomic risks associated with its use, such as cumulative trauma disorders (CTDs). This thesis was completed in collaboration with Covidien Surgical Solutions in North Haven, CT, and involved three specific phases of work. The first phase consisted of selecting an existing laparoscopic instrument for redesign and conducting relative extensive literature reviews and user-based feedback surveys and interviews. Twelve families of laparoscopic devices were evaluated in this phase and the surgical suture device (i.e., Endo Stitch) was identified to have several significant ergonomic risks. The second phase consisted of an extensive redesign and modeling process, including theoretical and computational analyses and design optimization, while the third phase consisted of subject-based biomechanical experiments, involving a simulated surgical task to validate the efficacy of the developed prototype, and a feedback survey that was completed following the experimental trials.

Preliminary research in phase one examined variations between men and women in grip strength and hand size (i.e., 50% and 15%, respectively), which established the specifications and constraints needed for the design of a next generation prototype. During phase two, the implementation of several design processes, such as Computer Aided Design (CAD), Finite Element Analysis (FEA), and two-dimensional static Free Body Diagram (FBD) modeling, yielded a mechanically robust prototype that functioned consistently and satisfied all specifications and constraints defined in phase one. Biomechanical experiments were conducted in phase three on five surgeons, each with significant laparoscopic suturing experience. These experiments involved the use of surface electromyography (sEMG) and point force sensors to monitor and study muscle activity levels and gripping force magnitudes, respectively, during the operation of the instruments in a simulated surgical task. Results from the third phase showed that the new prototype had up to a 40% reduction in suturing time, which would significantly decrease the total amount of time spent on surgical closures and further reduce the total time the surgeon is exposed to instrument use. Results from the post-experiment feedback surveys demonstrated that the next generation prototype is preferred over the original instrument.

Completion of all three phases resulted in the efficient development of a next generation laparoscopic suturing instrument that met all ergonomic specifications and preliminary design constraints and successfully enhanced usability and minimized ergonomic risk. Also, the work performed in this design thesis validated the surgical viability of the new prototype and effectively demonstrated its beneficial ergonomic improvements.

Major Advisor

Donald Peterson

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Available for download on Thursday, August 21, 2025

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