Transcript Document

BMEG450: Senior Design, Fall 2013
A Novel Fat Removal Tool for Human Tissue
Brandon Boles, Audrey Guyer, Ryan Mitchell, Krunal Parikh, Matthew Ringer
Overview
Concept Generation
Final Design
Background Information
Concept Selection
Prototype
LifeCell™ Corporation processes donated human skin
tissue into allografts to be used in surgeries.
Currently, scalpels (see Figure 1) are used to remove
the fat layer from the dermis before further
processing takes place. The current technique leads
to a non-uniform product and worker injury.
Figure 1: Scalpel blade and handle
The Product
LifeCell™ aims to alleviate safety concerns and
improve the uniformity of their final allograft
products by implementing a new fat removal system
to replace the use of scalpels.
Project Scope
The scope of the project is to develop a functional
prototype to remove adipose tissue from the dermal
layer of donated human skin while also promoting
technician safety and increasing functionality over
the current process.
Metrics
Metrics were developed in consultation with LifeCell™
to address the project constraints (see Table 1).
Table 1: Metrics for the fat removal tool
Metric
Technician Incidents:
No puncture wounds
Technician Fatigue:
50% reduction
Fat Removal:
100 % fat removal
Dermal damage:
80% reduction
Cost: $20 disposable cost
C
A
Figure 2: Concepts A, B, and C
B
Concept A (see Figure 2) was selected based on discussions with
LifeCell™. This device incorporates a bumper system that will protect
the dermal layer, an electrical component that reduces worker
fatigue, longitudinal motion that will reduce worker injury, a blade
replacement mechanism, and a trigger to activate the device.
Design Process
First Generation
This prototype featured a permanently installed
stainless steel blade on the Remington™ HC5550.
The prototype was tested on pork belly (Figure 3) to
simulate donated human skin, as highlighted in
green, and it was compared to a static blade (red).
The stainless steel blades have a serrated cutting edge
and are held in place by a 3-pin system. The blades are
removable by unscrewing the stainless steel bumper.
See Figure 6 for a model of the final design.
Figure 3: Pork Belly test
Second Generation
This prototype featured a removable stainless steel razor blade held
in place by a 3-pin system. A blade guard made of Delrin was
installed above the blade mechanism to prevent adipose tissue from
entering the device. This prototype was also tested on pork belly, as
seen in Figure 4.
Third Generation
This prototype incorporated
a trigger button mechanism to increase
control and minimize potential harm to the
technicians. This prototype was tested on
human tissue at LifeCell™ in Branchburg,
New Jersey (see Figure 5).
In order for the design to be implemented, it must be
superior in comparison to the current scalpel technique.
Figure 4: Blade with pin system
A qualitative feedback survey was administered to the
technicians at LifeCell™. The survey includes questions on
-ease of use
-learning curve
-comfort
-functionality
-dermal damage
Constraint
Safety
Figure 6. Final design
The final design is an
18,000 rpm motor with a
torque rating of 771 gcm. It is powered by
3-6 V of rechargeable
batteries that are in
circuit with a safety
toggle switch and trigger
button to initiate blade
movement.
Figure 5: Visit to LifeCell
Testing Plan
Testing of the final design was completed by the senior
design team and technicians at LifeCell™. The final design
was used in removing adipose tissue from human skin, and
the new design was rated against the current scalpel
method for each metric.
Validation
Fourth Generation
This prototype incorporated a modified stainless steel bumper below
the blade in order to minimize the possibility of human error in terms
of inflicting dermal damage during fat removal. As well, this
prototype used a blade with curved edges to promote cutting.
The feedback from LifeCell™ was used to validate the final
design against the project metrics.
Functionality
Acknowledgements
Cost-efficient
We would like to thank our sponsor, LifeCell™ Corporation, our advisor
Dr. Anita Singh, as well as Mr. Beard and the rest of the Senior Design Staff.
After hand-off of the final prototype to the sponsor, the
path forward will be to produce an autoclavable replica for
evaluation and eventual commercial use by technicians in
the class 100 cleanrooms at LifeCell™.
Safety
Functionality
Path Forward