[Different types of nerve injuries in locoregional anesthesia]

Neural damage is a possible complication of central nerve blockade and regional anaesthesia. Damage may be caused by ischaemic, mechanical or chemical mechanisms, which may occur either alone or in combination. Neural ischaemia may be caused by 1) prolonged and severe arterial hypotension, which compromises blood supply to the cord, 2) a spinal haematoma whose main etiological factor is a coagulation abnormality and 3) an intraneural injection. Mechanical trauma by the needle bevel is an important factor of neuropathy, particularly when searching for paraesthesiae. Neurological complications may also result from a direct neurotoxic effect of local anaesthetic agents which is concentration and dose-dependent. Better understanding of these mechanisms will permit the establishment of reliable bases for new preventive strategies.