2 + 6-DOF Multi-Purpose Laparoscopic Instrument
This
handpiece is designed for software developers who need a multi-purpose
laparoscopic handpiece that precisely reports its position and
orientation, as well as shaft rotation, and thumb trigger actuation.
Like most of our other tools this piece is precision CNC machined out
of Acetal and Stainless Steel to provide an extreme durability and long
life under continuous use without any device maintenance.
Background Information
We wanted to address the need for a medical simulation tool
that could provide simulation feedback for various laparoscopic tools
such as a needle driver, bowel grasper, or stapler. With an embedded
6-DOF tracking system, and USB feedback of additional axes, the tool
can be used with medical mannequins and box trainers. A narrow shaft
allows it to be inserted through standard trocars or other small
openings in the training device.
Our Design
Our
goal was to eliminate the issues common to existing VLI handpieces. To
do this we first started our own custom design of the tool body. We
then added our own electronics and optics. Finally we made the
handpiece cabling field-serviceable should cables need to be replaced
from the stresses of continuous use in training environments.
Metal Insertion Shaft -
To prevent flex of the shaft inserted into the trocar, mannequin, or
box trainer, we machined a piece of stainless steel with beveled edges.
This allows non-marring insertion into the device of choice and allows
us to use a narrow shaft that is compatible with standard trocars that
can be inserted into medical mannequins.
Stainless Steel Components
- Stainless Steel stands up well to the variety of body chemistries and
cleanings these devices are exposed to in a training environment, such
as a medical simulation lab in a training hospital. We try to use
high-quality plastics whenever possible. However, when metal components
are necessary, we use SS to prevent rust and damage from continuous use
and exposure to human contact. These handpieces use SS for the body
screws, insertion shaft, and rotation point pins.
Acetal - Our
Acetal body resists damage from body chemistry, cleaning solvents, and
abuse such as dropping, that are common in resident training
environments. Acetal also has self-lubricating properties that we
utilize for an extremely long service life that is completely
maintenance free. We custom design each tool body for a specific
purpose and precisely CNC machine it from Acetal billet. Sleeve
bearings are integrated directly into our Acetal designs, directly
mating with other Acetal, or Stainless Steel components to create
low-friction, smooth operating, maintenance free points of rotation.
Monocoque -
Using a monocoque design allows us to create a compact tool design that
encloses internal circuitry and acts as a load-bearing and active
structure. The design for these handpieces also precisely places and
focuses the internal optics of the tool for reliable operation over the
lifetime of the handpiece.
Digital Signal Processing
- Other handpieces use analog processing internally, generally through
the use of an analog magnetic sensor fixed to the tool body and a
moving permanent magnet attached to the thumb control. Unfortunately
that design requires user calibration from handpiece to handpiece as
the magnet and sensor may have slight variances from one unit to the
next. To eliminate that problem we process everything digitally inside
our handpieces. As the shaft is rotated or the thumb control is
actuated they pulse light beams inside of our tools. A signal processor
measures the absence and presence of the light beam reflections and can
digitally measure the exact level of actuation of the thumb trigger or
rotation of the insertion shaft. All of our units produce exactly the
same output from one unit to the next.
Glass-Free Optics
- Often glass is a superior material for use in precision optics.
Unfortunately glass is often too fragile for application in medical
simulation. Even glass optics that are protected by a very robust case
eventually experience damage due to the repetitive drops from medical
residents. To prevent this point of failure we use high-quality plastic
and metal optics in our devices. Our beam transceivers and optical
lenses are all plastic. Our optical discs consist of stainless steel or
anodized aluminum with high-resolution alternating transparent and
opaque plastic overlays. These resilient components withstand repeated
high-impact drops without failure.
6-DOF Internal Sensor -
Our handpieces internally accommodate the RX1C sensor from Polhemus.
Using Commercial Off The Shelf (COTS) sensors we can provide feedback
that is sub-millimeter for position and sub-degree for orientation.
USB Output - In
addition to the 6-DOF tracking, our devices track shaft rotation and
thumb trigger actuation, as mentioned above. This data is reported back
via USB. This allows software developers to interrogate the tool
positions at any time using a standard hardware interface.
HID Interface -
For software developers who wish to eliminate driver installs
altogether, we offer USB's Human Interface Device (HID) class firmware
for our tools. Because the HID drivers are built into the operating
systems of Linux, Macintosh, and Windows our devices can begin
communicating with software without the need for any driver
installation. We write our USB firmware and can arrange the HID data in
any format as requested by the software developers.
Virtual Com Port / Communications Device Class Interface - For
software developers who wish to have a traditional interface we offer
USB's Communications Device Class (CDC) firmware
for our tools. The CDC drivers are built into or available for
the Linux, Macintosh, and Windows operating systems. This allows
the software developers to see our devices as a traditional Com port,
even though the device is connected via USB. We write our USB firmware
and can arrange the CDC data in
any format as requested by the software developers.
Tri-Service Open Platform for Simulation (TOPS) Compatible / CDC Encapsulation - For
software developers who wish to have a traditional interface with
extended reporting channels, we
offer USB's Communications Device Class (CDC) firmware
with CDC Encapsulation support for our tools. This firmware offers all
of the advantages of CDC described above, but also adds a metadata
channel that is independent of the primary bulk data channel. This
encapsulated channel can be used to convey additional device data in a
separate data stream. It is the method of channel description
information in the US Department of Defense's upcoming Tri-Service Open
Platform for Simulation (TOPS) protocol on USB. We write our USB
firmware and can create a custom TOPS device for your application.
FTDI Turnkey Chips
- For
software developers who wish to have an FTDI interface we offer
USB handpieces with the FTDI chipset onboard. We develop our own custom
printed circuit boards (PCB) and can design an FTDI board design for
your specific needs.
Project Summary
Our
multi-purpose handpieces are in continuous use at a variety of
government and medical training institutions. Thanks to the use of high
quality materials and careful design these tools are known for having a
flawless record of operation.
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