Sensory potential can be preserved in severe common peroneal neuropathy.

Neuropathy of Common Peroneal Nerve (CPN) is a frequent clinical condition, generally caused by compression at the fibula head. Three neurophysiological patterns were described: 1) segmental demyelination with conduction block; 2) axonal damage with loss of motor units and sensory potential; 3) a mixed pattern. We report 5 patients with foot drop in whom CPN neuropathy was identified. In 3 in spite of impressive abnormalities in various motor branches and fascicles of the nerve, the peroneus nerve sensory potential remained well preserved. Focal neuropathies can be remarkably selective in terms of motor and sensory deficits, the reason can rely on a different location of the fibres or be related to a distinct histological-biochemical constitution. A preserved SPSP should not exclude a CPN neuropathy.