An amputated nerve transferred to a nearby muscle produces a transcutaneously detectable electromyographic signal corresponding to the transferred nerve; this technique is known as targeted muscle reinnervation (TMR). There are 2 issues to overcome to improve this technique: the caliber and the selectivity of the transferred nerve. It is optimal to select and transfer each motor fascicle to achieve highly developed myoelectric arms with multiple degrees-of-freedom motion. The authors report on a case in which they first identified the remnant stumps of the amputated median and radial nerves and then identified the sensory fascicles using somatosensory evoked potentials. Each median nerve fascicle was transferred to the long head branch of the biceps or the brachialis branch, while the short head branch of the biceps was retained for elbow flexion. Each radial nerve fascicle was transferred to the medial or lateral head branch of the triceps, while the long head branch of the triceps was retained for elbow extension. Electrophysiological and functional tests were conducted in the reinnervated muscles. Functional and electrophysiological improvement was noted, with marked improvement in the identification rate for each digit, forearm, and elbow motion after the selective nerve transfers. The authors note that more selective nerve transfers may be required for the development of prostheses with multiple degrees of freedom.
ABBREVIATIONSAIN = anterior interosseous nerve; DASH = Disabilities of the Arm, Shoulder and Hand; EMG = electromyography; MUP = motor unit potential; n-EMG = needle EMG; PIN = posterior interosseous nerve; s-EMG = surface EMG; SSEP = somatosensory evoked potential; TMR = targeted muscle reinnervation; VAS = visual analog scale.
Correspondence Takehiko Takagi: National Center for Child Health and Development, Tokyo, Japan. email@example.com.INCLUDE WHEN CITING Published online February 22, 2019; DOI: 10.3171/2018.10.JNS181865.Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.