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`JUNE 1,2018
`| MEDICAL | MANUFACTURING& PROTOTYPING |
`DESIGN
`Ergonomics and Handheld Medical Devices: Five
`Vital Elements for Design Success
`
`Dexterity, precision, control and comfort — without them, no handheld or hand intensive medical device is
`a success, for either the medical professional using it or for the patient relying on the outcomes.
`Ergonomically driven design guides a successful device development process from concept through
`prototype to market. There are always five fundamentals required for world-class handheld instruments or
`hand-intensive devices.
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`Document title: Ergonomics and Handheld Medical Devices: Five Vital Elements for Design Success - Medical Design Briefs
`Capture URL: https://www.medicaldesignbriefs.com/component/content/article/29108-ergonomics-and-handheld-medical-devices-five-vital-elements-for-design-success
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`Petitioner Therabody Ex-1018, 0001
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`

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`‘Comparison between Sth percentile female to 95th percentile male hand sizes.
`
`a lot of talk about user needs in product development, but it doesn't always translate into
`‘Sometimes there is
`meaningful insights from and about users. Users are often overlooked and undervalued, and mastering their
`universe will deliver the highest return on design development time and investment. What to do? Categorize
`by type all of the users that will interact with your product. For example, individual users that interact with
`atypical surgi
`1 device all touch it in distinct ways. The surgeon focuses on the procedure and is heavily
`impacted by the instrument design, especially where fingertips and instrument meet. An assisting surgical
`nurse will interact with the surgical tool in support of the surgeon's role, but also in terms of the surgical
`
`field. Technicians in central processing are focused on cleaning and ster
`zation and has unique handling
`requirements for the device. There is no substitution for a thorough user design audit at the very start of
`product development.
`
`Observing, listening, and asking que
`ns are central to understanding users’ needs — their articulated and
`often unarticulated states of need that will run from “must haves” to “
`ants.” Remember that what people
`say they do and how they actually behave is never the same thing, so i
`vital to both ask them to describe
`is
`what they do and observe real behavior. Listening to descriptions of actions provides insight into user
`perception of usability, utility, and the emotional content of the experience. Watching how people behave
`will reveal how they physically use the design and highlight “work-arounds” that offer valuable insights for
`redesigning the product to make it more effective and efficient to use. Behavioral hiccups are often poor,
`nonintuitive design elements driving inefficient behavior.
`
`Wherever possible, video record the current product or process to memorialize real-world workflow that
`includes the product in context of all of the other products and processes that affect it during a clinical or
`surgical procedure. In-depth examination of video footage will
`
`
`isclose interaction sequences and patterns
`impacts on dexterity, precision, control, and comfort.
`and offer multiple opportunities to identify negative
`
`THE (ALMOST) INFINITE VARIETY OF THE HUMAN HAND
`Humankind comes in many different shapes and sizes. As do human hands. Best design practice targets the
`Sth percentile female hand to the 95th percentile male hand to accommodate the physical range of grasp,
`motion, and flexion. Handheld and hand-intensive design for precision instruments must accommodate a
`range of 1.75 in. in hand length and 1 in, in hand width. The diversity of human hands frames the principal
`challenge in designing handheld products: what achieves the highest level of usability excellence across a
`population of diverse users. A goal in design is to find the dimensional sweet spot where the instrument fits
`hand size perfectly and empowers the greatest degree of precision and dexterous control for as many users
`as possible.
`
`The innate geometries of the hand impact handheld and hand-intensive products at a core level. When a
`user closes his or her finders and grasps an instrument, a “grip axis” presents, as do three palmar arches
`that position the user's fingertips on the device. Combining hand geometry hand with size and strength sets
`the design definition where fingertip grip surfaces and controls should be located on the device for ideal
`precision, control, and comfort.
`
`EVERY DETAIL MATTERS
`
`
`
`
`
`
`
`
`
`Document title: Ergonomics and Handheld Medical Devices: Five Vital Elements for Design Success - Medical Design Briefs
`Capture URL: https://www.medicaldesignbriefs.com/component/content/article/29108-ergonomics-and-handheld-medical-devices-five-vital-elements-for-design-success
`
`Capture timestamp (UTC): Thu, 16 Jan 2025 21:45:07 GMT
`Page 2 of 7
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`Petitioner Therabody Ex-1018, 0002
`
`

`

`MENG
`
`MEDICAL
`DESIGN BRIEFS
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`Losin sicnup
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`i
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`Pumps
`textures that bite in the surgical glove that are perpendicular to the direction of the force being applied.
`
`Control surfaces on Zimmer's Persona Surgical Knee
`
`Alignment Guide are sculpted to fit gloved fingertips with
`
`Hands have amazing tactile sensitivity. A fingertip discerns a raised dot only 3 um high on a sheet of glass
`and a palm differentiates a 0,009 in,
`in the height of a computer mouse. Tactile sensitivity combined with
`the physical properties of the product define haptic signature — how the product feels and performs in the
`hand, Perfect balance, controls located where fingertips naturally fall on a product's surfaces, and optimal
`size for range of hands will always enhance user dexterity, precision, control, and comfort.
`
`A product's haptic signature defines its “hand feel” and is delineated by form, balance, scale, weight,
`textures, and materials. In most designs for handheld or hand-intensive devices, balance is the most critical
`factor that impacts surgical and clinical performance. As a design general rule of thumb, bring the center of
`gravity of the instrument as close as possible to the virtual center point of the precision grip being used.
`This minimizes any arm movement and/or pendulum effect that will impact precision and control,
`
`Tethered handpieces complicate haptic design decisions. Cord whiplash has an impact on how a device
`feels in the hand. Many medical and surgical devices have power, suction, or irrigation lines (generally at
`the back of the device) that further complicate haptics and balance. All of these factors combine to create
`line tug that requires the user to constantly counterbalance, creating stress and decreasing precision and
`control of the device tip. Wherever possible in design, use free floating articulating strain reliefs to
`minimize “line tug” on the back of handpieces.
`
`Don't underestimate the need for detailed attention to the potency of product aesthetics. Functional
`aesthetics — not just “cool design” — tells a story and gives visual cues to the user on the best way to
`interact with the product.
`
`a
`
`Document title: Ergonomics and Handheld Medical Devices: Five Vital Elements for Design Success - Medical Design Briefs
`Capture URL: https://www.medicaldesignbriefs.com/component/content/article/29108-ergonomics-and-handheld-medical-devices-five-vital-elements-for-design-success
`Capture timestamp (UTC): Thu, 16 Jan 2025 21:45:07 GMT
`Page 3 of 7
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`Petitioner Therabody Ex-1018, 0003
`
`

`

`MENG
`
`MEDICAL.
`DESIGN BRIEFS
`
`Losin sicnup
`
`grips. The
`Medtronic's Hydrodebrider handpiece epitomizes the perfect balance between power and precision
`ring and pinky finger easily wraparound the handle securing the device, freeing the index finger to rotate the
`scalloped tip
`direction control, the thumb to swipe up and down to increase/decrease the spray window angle,
`leaving the middle finger to operate the trigger.
`
`For example, designing an instrument grip with three opposing sculpted surfaces that approximate the same
`curvature of the thumb, index, and middle fingers will immediately convey an unambiguous cue to users to
`apply a highly dexterous trilateral precision grip. This visual information is called an affordance and is an
`essential concept when developing functional aesthetics that lead to intuitive and easy-to-use products that
`optimize human performance.
`
`THE BEST HIGH-DEXTERITY GRIP
`Human hands have smart and dumb fingers. The most dexterous fingers are the thumb, index and middle
`fingers on the dominant hand and are used in virtually all high-precision and high-control tasks with
`handheld devices. This tri-lateral grip uses the smart fingers to the highest advantage in handheld devices.
`These are the fingers that surgeons and clinicians use to rotate or “twiddle” a device or instrument
`throughout a procedure to achieve the greatest degree of precision and control of a device.
`
`Medtronic's MS Microdebrider is designed for a high dexterity trilateral grip where the middle finger opposes the
`thumb providing the grip security, freeing the index finger to operate the rotary control for the cutting window.
`
`The clear majority of all medical devices and instruments should be optimized for the highly dexterous
`trilateral grip. Trilateral grasping provides an excellent balance between dexterity, precision, control and
`comfort and enables surgeons and clinicians to precisely control devices fractions of a millimeter in and
`out, rotate it 1-2°, and perform lateral sweeping motions and compressions. Successful ergonomic design
`that utilizes the trilateral grip empowers the hand to achieve the greatest range of motion, control and
`precision and produces a highly functional handheld device.
`
`When a procedure involves a handheld tool that requires force, the design will include a power grip — the
`palm engaged, the thumb opposed to or inline with the aligned fingers, and the hand wrapped around the
`instrument. This grip allows for the engagement of the muscles of the upper arm to apply significant force.
`
`Designs for orthopedic surgery will include the power grip for instruments such as a small bone saw. The
`surgeon must apply high force to the saw tooltip and apply significant pressure down on the blade. This,
`power grip application must have the highest degree of grip stability to counteract the saw from skipping
`across the bone.
`
`
`
`CONTROL SURFACES
`
`
`
`Document title: Ergonomics and Handheld Medical Devices: Five Vital Elements for Design Success - Medical Design Briefs
`Capture URL: https://www.medicaldesignbriefs.com/component/content/article/29108-ergonomics-and-handheld-medical-devices-five-vital-elements-for-design-success
`Capture timestamp (UTC): Thu, 16 Jan 2025 21:45:07 GMT
`Page 4 of 7
`
`Petitioner Therabody Ex-1018, 0004
`
`

`

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`CONTROL SURFACES
`
`Power grip affords highest sustained downward blade forces and the most stable grip to prevent saw from
`“walking and skipping” across bone.
`
`The ergonomic rule for the design of control surfaces is to sculpt the area where the fingertips naturally
`land to provide the user to fingertip control to steer and manipulate the instrument. The indents on these
`types of control surfaces should be the same size and curvature of the thumb, index, and middle fingertips
`— the three digits used in the highly dexterous trilateral grip. Ergonomic control surfaces must function for
`both left and right-handed users and the design for size and location unbiased toward both hands.
`
`Ergonomic control surfaces are typically textured to reduce slippage and to optimize control. To design the
`best texture first determine the direction and amount of force required for the device, then design a textural
`field that will allows fingertips to “bite in” to provide traction with the force needed.
`
`The ergonomic design concept of dynamic grip security strongly affects control surfaces in handheld
`medical devices. Dynamic grip security in handheld devices is the ability to securely hold an instrument in
`the hand while simultaneously operating fingertip controls with fingers on the same hand. This action is
`frequently necessary in a handheld or hand intensive medical device.
`
`The design challenge is to create product forms that allow the user to apply a hybrid of the precision grip
`and the power grip. An ergonomic solution to this challenge is to anchor design in the natural geometry of
`the hand and combine the ring finger and baby finger into one coordinated powerful “super” finger. The
`“super” finger provides a secure grip, freeing the thumb, index, and middle fingers to operate in the
`dexterous and controlled trilateral precision grip in tandem with the appropriately designed control surface.
`
`Medtronic's Hydrodebrider handpiece epitomizes the perfect balance between power and precision grips.
`The ring and pinky finger easily wrap around the handle securing the device, freeing the index finger to
`rotate the scalloped tip direction control, the thumb to swipe up and down to increase/decrease the spray
`window angle, leaving the middle finger to operate the trigger.
`
`HITTING THE ERGONOMIC DESIGN TARGET
`These five factors — user focus, hand architecture and dynamics, attention to details, complex grip
`solutions, and tactile control surfaces — are not the only elements of ergonomic design for handheld
`medical devices. They are, however, absolutely essential, and no handheld or hand-intensive device will
`succeed without them, They are at the heart of ergonomic design and will dynamically inform the creation
`of superior devices that empower exceptional performance.
`
`This article was written by Bryce G. Rutter, PhD, Founder and CEO of Metaphase Design Group, Inc., St.
`Tonic MO He can he reached at hrvco@metanhase cam Kar mare infarmation Click Hore
`
`
`
`Document title: Ergonomics and Handheld Medical Devices: Five Vital Elements for Design Success - Medical Design Briefs
`Capture URL: https://www.medicaldesignbriefs.com/component/content/article/29108-ergonomics-and-handheld-medical-devices-five-vital-elements-for-design-success
`Capture timestamp (UTC): Thu, 16 Jan 2025 21:45:07 GMT
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`Petitioner Therabody Ex-1018, 0005
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`This article was written by Bryce G. Rutter, PhD, Founder and CEO of Metaphase Design Group, Inc., St.
`Louis, MO. He can be reached at bryce @metaphase.com. For more information, Click Here (2
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`Topics:
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`Document title: Ergonomics and Handheld Medical Devices: Five Vital Elements for Design Success - Medical Design Briefs
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`Petitioner Therabody Ex-1018, 0006
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`Document title: Ergonomics and Handheld Medical Devices: Five Vital Elements for Design Success - Medical Design Briefs
`Capture URL: https://www.medicaldesignbriefs.com/component/content/article/29108-ergonomics-and-handheld-medical-devices-five-vital-elements-for-design-success
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`Capture timestamp (UTC): Thu, 16 Jan 2025 21:45:07 GMT
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`Petitioner Therabody Ex-1018, 0007
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