Microelectrode recordings from transected nerves in amputees with phantom limb pain.

Intraneural microelectrode recordings were made from the nerve supplying the phantom area in two patients suffering from phantom limb pain. Spontaneous activity was prominent in both cutaneous and muscle fascicle of the nerves. Tapping the neuromata which accentuated the phantom limb pain, induced afferent discharges with both short and long latencies, the latter from fibres with a conduction velocity of only 0.5 m/sec. Blocking the neuromata with lidocaine completely abolished the tap-induced afferent discharges and the tap-induced accentuation of the phantom pain. The spontaneous pain was, however, unchanged, as was the spontaneous activity recorded.