Article

There are indications that perilesional and remote peripheral motor
axons may degenerate after spinal cord injury (SCI). The authors investigated the
magnitude and dependence on severity of SCI of this degeneration as well as
whether motor axons so affected can recover. METHODS: The function of the
peripheral motor axons was investigated by recording compound muscle action
potentials (CMAPs) in 345 patients with cervical SCI. CMAP amplitude changes in
the abductor digiti minimi (ADM) and abductor hallucis (AH) muscles were
investigated in 3 groups with SCIs of differing severity: patients with permanent
complete SCI (ASIA Impairment Scale [AIS] A-remain), patients with initially
complete SCI converting to incomplete lesion (AIS A-convert), and patients with
incomplete injury (Incomplete). RESULTS: Significant decreases in ADM and AH CMAP
amplitudes were found in groups A-remain and A-convert. In group A-remain and
group A-convert, the authors found a partial, although significant, recovery of
ADM CMAP amplitude occurring between 5 and 12 months postinjury. In group
A-remain, they found significant recovery of the AH CMAP amplitude. CONCLUSION:
Following SCI, peripheral motor axons below the level of the lesion exhibit
severe degeneration. There is partial, although significant, recovery of CMAP
during the second half year following SCI. The observed motor axon dysfunction is
likely a result of transsynaptic degeneration. The peripheral motor axon
dysfunction observed after SCI is of sufficient magnitude that it may affect
muscle power and thus contribute to impairment of recovery of functional
activities in patients with SCI.

Langue : ANGLAIS