Page 220 - Handbook of Biomechatronics

Upper-Limb Prosthetic Devices 217

to “feel” where his or her prosthesis is without seeing it. The information
comes integrative to the amputee by using the remaining afferent (sensory)
pathways which are now integrated with the prosthesis and give us an EPP
type of control which we know from the past that has advantages over other
prosthesis control topologies (Childress, 1997, 1998; Doubler and
Childress, 1984a).
For upper-limb amputees, the protocol, and device are part of the
Osseointegrated Human-Machine Gateway (OHMG) (Ortiz-Catalan
et al., 2014a). The osseointegration implant provides also the gateway or
“corridor” for intramuscular EMG electrodes to be placed in the muscles
and the wires to come out (Ortiz-Catalan et al., 2013, 2014a). OHMG
should be viewed as a platform. Fig. 19 describes all the details of the OHMG
platform.
A modified OHMG platform could be used in the future for lower limb
Osseointegration prostheses.
As we mentioned before, one of the benefits of all Osseointegrated pros-
theses is the Osseoperception provided by the receptors and the direct
mechanical linkage provided. Therefore, the OHMG, facilitates the integra-
tion (and thus “Integrum” is a good name) of the motor and sensory aspects
needed for upper-limb prostheses, eliminating the need for wireless
interfaces.
All the potential benefits and advantages of osseointegration do not come
without problems. The biggest problem of this technique is its long lasting
battle with bacteria at the skin interface and its unknown long-term impact
on the quality of the bone fixture (Lenneras et al., 2017). Therefore, long-
term studies are needed. Radiologically found endosteal bone resorption
accompanied with pain at loading might be associated with potential weak-
ness of the bone fixture (Lenneras et al., 2017). Different osseointegration
research groups are taking nine different engineering variants of the implant
designs and materials in order to achieve a stable mechanical interface
between the bone and the implant (Thesleff et al., 2018). The prominent,
the ORPA treatment protocol, which involves the traditional surgical tech-
nique from Sweden and rehabilitation protocol, involves a threaded
titanium abutment screwed into the medullary cavity of the bone
(Fig. 20) and a long rehabilitation phase. This treatment protocol has been
adapted for transhumeral, transradial, thumb, or finger amputations of the
upper limb (Thesleff et al., 2018).
More comparative details on the different surgical techniques and
implant systems are given in Thesleff et al. (2018).