Short-term peripheral nerve stimulation ameliorates axonal dysfunction after spinal cord injury.
There is accumulating evidence that peripheral motor axons deteriorate following spinal cord injury (SCI). Secondary axonal dysfunction can exacerbate muscle atrophy, contribute to peripheral neuropathies and neuropathic pain, and lead to further functional impairment. In an attempt to ameliorate the adverse downstream effects that developed following SCI, we investigated the effects of a short-term peripheral nerve stimulation (PNS) program on motor axonal excitability in 22 SCI patients. Axonal excitability studies were undertaken in the median and common peroneal nerves (CPN) bilaterally before and after a 6-wk unilateral PNS program. PNS was delivered percutaneously over the median nerve at the wrist and CPN around the fibular head, and the compound muscle action potential (CMAP) from the abductor pollicis brevis and tibialis anterior was recorded. Stimulus intensity was above motor threshold, and pulses (450 μs) were delivered at 100 Hz with a 2-s on/off cycle for 30 min 5 days/wk. SCI patients had consistently high thresholds with a reduced CMAP consistent with axonal loss; in some patients the peripheral nerves were completely inexcitable. Nerve excitability studies revealed profound changes in membrane potential, with a "fanned-in" appearance in threshold electrotonus, consistent with membrane depolarization, and significantly reduced superexcitability during the recovery cycle. These membrane dysfunctions were ameliorated after 6 wk of PNS, which produced a significant hyperpolarizing effect. The contralateral, nonstimulated nerves remained depolarized. Short-term PNS reversed axonal dysfunction following SCI, may provide an opportunity to prevent chronic changes in axonal and muscular function, and may improve rehabilitation outcomes.
['Lee|Michael|M|', 'Kiernan|Matthew C|MC|', 'Macefield|Vaughan G|VG|', 'Lee|Bonne B|BB|', 'Lin|Cindy S-Y|CS|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D000704:Analysis of Variance D001369:Axons D004558:Electric Stimulation D005260:Female D007839:Functional Laterality D006801:Humans D008297:Male D008875:Middle Aged D009431:Neural Conduction D010525:Peripheral Nerves D013119:Spinal Cord Injuries D018709:Statistics, Nonparametric D055815:Young Adult
peripheral nerve stimulation spinal cord injury nerve excitability rehabilitation