ABSTRACT
After an amputation, severed residual nerves continue to transmit motor control information intended for the missing limb (Gordon et al. 1980). This neural activity may persist for decades, if not indefinitely (Davis et al. 1978; Dhillon et al. 2004; Jia et al. 2007). In addition, severed nerves can successfully reinnervate nonnative muscles (Elsberg 1917), and these reinnervated muscles subsequently respond appropriately to nonnative nerve commands (Gordon et al. 1980; O’Donovan et al. 1985; Gordon et al. 1986). These key observations provided the basis for the development of targeted muscle reinnervation (TMR) (Kuiken 2003; Kuiken et al. 2004). TMR critically depends on two key elements: (1) robust reinnervation of target muscle and (2) generation of strong, independent electromyographic (EMG) signals. In this chapter, we review the scientific and physiologic principles that underlie the
CONTENTS
2.0 Introduction ....................................................................................................9 2.1 Principles of Targeted Muscle Reinnervation .......................................... 10
2.1.1 Hyper-Reinnervation of Muscle .................................................... 10 2.1.2 Long-Term Viability of Severed Nerves........................................ 12 2.1.3 Denervation of Target Muscle ........................................................ 12 2.1.4 Independent Reinnervation of Adjacent Muscles/Muscle
Segments ........................................................................................... 13 2.2 Optimization of the EMG Signal ............................................................... 13
2.2.1 Signal Strength ................................................................................. 13 2.2.2 Signal Separation ............................................................................. 15 2.2.3 Selective Transfer of Functionally Distinct Nerve Fascicles ...... 16
2.3 Conclusion .................................................................................................... 17 References ............................................................................................................... 18
successful implementation of TMR in human subjects and provide the foundation for further development of this technique.
