Clinical Trial Details
— Status: Recruiting
Administrative data
| NCT number |
NCT05220553 |
| Other study ID # |
JH596520 |
| Secondary ID |
|
| Status |
Recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
July 10, 2023 |
| Est. completion date |
August 1, 2025 |
Study information
| Verified date |
June 2024 |
| Source |
University Hospitals Coventry and Warwickshire NHS Trust |
| Contact |
Chris Bradley, MSc |
| Phone |
02476966197 |
| Email |
christopher.bradley[@]uhcw.nhs.uk |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The finger and fingertip are the most frequently amputated body parts, due to work-related
incidents. Yet because of space, weight and cost constraints, prosthetic fingers and
fingertips are heavy and bulky with limited active motion and sensation. Most are basic
variations on the hook and claw. Lower limb prostheses have become extremely technologically
advanced in their design and materials, and upper limbs lag behind in all of these areas.
This is due to the complexity of the anatomy and function of the upper limb compared to the
lower. There are no commercially available prostheses that offers direct sensory feedback and
as such, rely on visual feedback from the wearer.
The original PROLIMB study (PROLIMB I) used a Leap Motion Controller (LMC) to investigate the
type of grasp adaptation that have been undertaken by patients during the rehabilitation
process following amputation and compared this to similar data from healthy volunteers.
PROLIMB I also looked at refining the tactile feedback system by investigating the sensation
felt on amputation sites in order to feed this information into the haptic feedback system.
The vision of the PROLIMB II project is to build on the work completed in PROLIMB I and
develop and combine mechanistic models of hand motion and haptic sensing to deliver novel,
affordable body-powered prosthetic fingertip digits with enhanced motion and sensation to
address current clinical needs and support the quality of life of amputees. With
collaboration from the University of Warwick (UoW) and University College London (UCL),
Steeper Group and Naked Prosthetics the PROLIMB II study will aim to model, design, fabricate
and validate a body-powered prosthetic fingertip digit with integrated sensory feedback. The
University Hospital Coventry & Warwickshire (UHCW) will provide the clinical facility with
which to assess the comfort, usability and acceptance of this prosthetic in the daily lives
of patients with digit amputations. This project will be a proof of concept study with
verification of the prosthetic in motion capture (gait) laboratories as well as the use of
simple validation data collection over a longer period.
Description:
Worldwide, there are about 3 million upper limb amputees - 80% of these people live in
low-income countries. Only 2% have access to prosthetic care. The World Health Organization
and Prosthetics Outreach Foundation identified a number of reasons why patients in low-income
countries do not have access to prosthetics: lack of trained personnel, frequent replacement
and repair (prosthetic replacement is needed typically every 6-12 months for children and
every 3-5 years for adults). This problem is not limited to developing countries: in the UK,
the prostheses available from the National Health Service (NHS) have either a greatly
simplified choice of actions available or are too expensive to be routinely funded.
Upper-limb amputees suffering from traumatic injuries require long-term, frequent intensive
medical care (work-related injuries cause the highest number of days away from work) and
psychological support. NHS England spends approximately £60m/year on services for patients.
Current prostheses are limited to cosmetic devices that fail to recover the original
functionality of the hand. Up to 20% of the adult population with upper limb amputations
choose not to use a prosthesis (Biddiss & Chau, 2017) - the prescribed device is discarded as
it is often seen as an obstacle. Of those that do accept a prosthesis, 26% of adults and 45%
of children and adolescents are dissatisfied with their device and choose not to use them
(NHS England, 2015). Hence, the NHS effectively does not provide service to over 50% of
upper-limb amputees. Reasons cited include poorly developed fine motor control, absence of
sensory function, weight and a lack of warmth and humanness.
Currently the NHS is working in collaboration with companies who uitilize 3D printing
technology to dramatically reduce the waiting time and costs of custom prosthetic hands. Open
Bionics' Brunel Hand is a simple myoelectric (using the electrical signals from the muscle)
control hook in the form of a human hand (open bionics, 2018). Although it is low-cost
(£1200) and at a price point that the NHS may fund, there are still areas in which it could
be improved, such as providing sensory feedback to the user. At present, the only form of
feedback that upper limb prostheses provide is visual, rather than tactile. As such, the user
must be able to see the prosthesis in order to use it effectively. A body powered prosthesis
with more grasps and therefore more functionality would also be preferred.
Body powered prosthetic devices are considered to have many advantages over myoelectric
devices due to their robust, rugged and predictable nature. Other companies currently
developing upper-limb prostheses include Touch Bionics, RSL Steeper, Ottobock and Defence
Advanced Research Projects Agency (DARPA). The prosthetic devices created by these companies
are much more expensive (approximately £20,000 - £75,000). All require an extrinsic power
source (e.g. battery) and with high complexity comes high maintenance and risk of failure.
None of the available prosthesis described provide any discrete tactile feedback.
Although sensory information can be relayed to patients via direct integration with the
central nervous system (Yildiz, et al., 2020), it is safer and simpler to provide this via
haptic feedback. A body-powered hydro elastic haptic sensor has been developed and can relay
fine sensory information from the tip of a prosthetic finger to an actuator that is in direct
contact with the sensate residual limb. Although the resolution of the sensitivity in the
residual limb is reduced (for example there is reduced ability to resolve between two
discrete points of contact), the actual light touch sensation is retained after injury (e.g.
on the residual palm or forearm). The haptic sensor and actuator can also amplify the signal
to improve sensitivity.
To design a body-powered sensory upper limb prosthesis, the action of the uninjured hand must
be fully appreciated. The hand requires function over form, rather than vice versa. Although
the visual appearance of a hand may be preferential, this can limit the design and
capabilities of the prosthesis.
Combining the synergetic expertise in developing parameterised mathematical models of limb
motion from the UoW and in creating soft, stiffness-controllable robotic structures, and
haptic feedback interfaces from UCL, the aim of this project is to model, design, fabricate
and validate a body-powered prosthetic fingertip digit with integrated mechanical haptic
feedback. Of key importance for the project's success is its transformative nature through
close collaboration with experienced clinical experts from the UHCW and the UHCW Innovation
Hub, who will offer consultation and clinical input throughout.
The PROLIMB II study is a single centre pilot study that will be testing the feasibility of
the trial design when integrating a tactile haptic feedback mechanism into prostheses. The
PROLIMB II study will utilise a pre-existing CE marked finger digit prostheses (Naked
Prostheses) and a non-CE marked prosthesis that has been created and designed by UCL. The CE
marked finger digit prostheses will be custom made and manufactured by Naked Prosthetics (NP)
- a commercial company in the USA that distributes their custom-fabricated finger prostheses
to the UK through a secondary company called Steeper Group (SG). The non-CE marked prosthesis
will be designed and manufactured by PROLIMB II researchers at UCL The PROLIMB research team
will modify the prostheses so that they provide participants with sensory feedback when
touching objects at the fingertip (full details of the device and modifications can be found
in section 1.3). Testing will also be conducted with the haptic feedback mechanism attached
to the residual stump, in order to collect sensation data.
The study will recruit up to 10 participants. The total number of patients consented into the
study may be greater than 10 as, following consent, NP are required to screen participants
who will be receiving their prosthesis and so may deem some participants as unideal
candidates for their prosthetic. If this occurs, participants will be offered the UCL
prosthesis to use instead. Potential participants will have had one or more finger/thumb
digits amputated through either accident or surgery within 1 year of consenting into the
study. The wound will be completely healed at the point of consent and the prosthesis/haptic
feedback system will not come into contact with an injured dermis. Potential participants
will be identified by delegated individuals of the PROLIMB research team at University UHCW.
If eligible, participants will be sent the study information pack and called to discuss the
study further. If the participant is happy, they will be invited to take part in the study.
For those who are receiving prosthetic devices from NP, these are custom-made for each
participant; therefore consented participants will then need to be screened by experts at NP.
This will involve the participants completing a partial hand information form and sending
photos and videos of the participant's hands showing their level of amputation and their
current range of motion. No personal data will be shared with Naked Prosthetics and all
photo's/videos will be pseudo-anonymised (linked to a unique participant ID) and only show
the participants hands/arms.
If deemed suitable, devices will be custom made for participants and sent to UHCW for initial
attachment and testing with the participant. Following this the prosthesis will be sent to
collaborators at UCL who will modify the prosthetic to incorporate tactile haptic feedback
into the fingertip and then returned to UHCW. The modified prosthetic will then be reattached
to the participant and further testing will take place (details of testing procedures can be
found in section 7.2). The prosthesis may also be supplied by UCL, further details of which
can be found in section 1.3.2.
Testing will continue over the next 10 months and take place at bi-monthly (± 3 weeks)
intervals at UHCW gait lab. Tests will be performed both with and without the PROLIMB II
prosthesis attached. All performance tests will be conducted whilst the participant is
recorded using a VICON Motion Capture System (VMCS). During each visit a series of
questionnaires and interviews will also take place to collect data related to participant's
satisfaction with the PROLIMB II prosthesis. At the end of the study, participants will have
the option to keep the PROLIMB II prosthesis if they wish, however they will be made aware
that this is without any form of warranty for the devices.
