Page 214 - Handbook of Biomechatronics

Upper-Limb Prosthetic Devices 211

Revolutionizing Prosthetics program with collaboration of many academic
institutions and DEKA. LUKE arm is commercialized by Mobius Bionics.
The technologies enabling this new generation of upper-limb prosthetics
are described further.

2.2 Targeted Muscle Reinnervation

One of the biggest challenges of prosthesis history was that high-level upper-
limb amputees did not had much fewer EMG control sites available than
needed DoF to control with the prosthesis. TMR is a novel surgical tech-
nique which was first introduced in 1995 by Dr. Todd Kuiken of North-
western University and the former Rehabilitation Institute of Chicago at
that time (Kuiken et al., 1995) and solved that problem. It is an extra surgery
but its return on investment (ROI), is the creation of additional EMG sites.
In 1995, the early experiments of Dr. Kuiken, muscle recovery of
hyperreinnervated rat skeletal muscle was found to lead to increased muscle
mass and strength compared to the self-reinnervated muscles (Kuiken
et al., 1995).
Having positive preliminary animal model results, Dr. Kuiken took his
idea to the next level and showed that in an elbow disarticulation amputee,
four independent nerve-muscle units were created by anastomosing residual
brachial plexus nerves (musculocutaneous, median, radial, and ulnar nerves)
of the amputated limb, to dissected and divided aspects of the pectoralis
major and minor muscles of the chest. After 5months, three reinnervations
were successful, that is, reinnervated pectoralis muscles were moving at the
command of the anastomosed brachial plexus nerves, offering additional
EMG sites for prosthesis control, which controlled successfully a three
DoF prosthesis: elbow, wrist rotator, and hand (Kuiken et al., 2004;
Miller et al., 2008). The muscle can be perceived as the “amplifier” of
the nerve, and getting a control signal for prosthesis control from a muscle
has less challenges than from a nerve (Childress, 1992; Hijjawi et al., 2006). It
was an unexpected discovery that the reinnervated sensory neurons,
reinnervated also the skin above the pectoralis muscle, providing sensation
of the fingers at the chest (Kuiken et al., 2007; Marasco et al., 2009). It seems
that the efferent nerves migrate from the reinnervated site through the mus-
cle and breast tissue and coexist with native chest efferents (Kuiken et al.,
2007). During this study, there was an attempt to reinnervate a skin area
away from the pectoralis area used for motor control (Kuiken et al.,
2007) but without any practical applicable solution for prosthesis control.