PMC5334286_01
Electromyogram recorded from the intercostal muscles (IC), distal to level of the transferred intercostal nerves (i.e., around eighth costal level; surface electrodes), as well as from the biceps muscle (biceps; needle electrode) after the second surgery. Recordings were done during deep breathing (upper panel) and during coughing (lower panel).
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F1
Examination with EMG after clinical signs of reinnervation, i.e., 1 year after surgery, showed extensive denervation activity in the biceps muscle with few neurogenic altered activated motor units in the muscle through activation of the intercostal nerves (i.e., essentially with coughing but also with deep expiration, Figure 1), although still suboptimal strength (M1-2).
Electromyogram recorded from the intercostal muscles (IC), distal to the transferred intercostal nerves (i.e., around eighth costal level; surface electrodes), as well as from the gracilis muscle (gracilis; needle electrode) after the second surgery, where the gracilis muscle was transferred as a free muscle graft and reinnervated by the phrenic nerve. Recordings were done during deep breathing (upper panel) and during coughing (lower panel).
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F2
The transferred gracilis muscle, innervated by the phrenic nerve, showed no denervation activity, but was rhythmically activated (a large number of motor units) during the inspiration phase of deep breathing (not with coughing; Figure 2), and by voluntary elbow flexion (weak M3).
Electromyogram recorded from the intercostal muscles (intercostal), distal to the transferred intercostal nerves (i.e., around eighth costal level; surface electrodes), as well as from the biceps muscle (biceps; needle electrode) after the second surgery. Recordings were done during voluntary elbow flexion (arrow indicates start of the voluntary flexion).
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PMC5334286_01_fneur-08-00072-g003.jpg
F3
Voluntary flexion of the elbow (weak M3; up to 30 degrees of flexion) elicited clear activity in the biceps/gracilis muscles, with minor activity in intercostal muscles (shown for biceps in Figure 3).