Lesions of primary afferent fibers as a tool for the study of clinical pain

Some of the most dramatic and most difficult pains to treat result from injury to primary afferent fibers. The validity of the models used in researching neuropathic pains by creating primary afferent lesions in animals is the controversial basis of this volume. The clinical and morphological aspects induced by these lesions are complex, leading to frequent mismatches between the injury and the clinical signs. Nomenclature is crucial to enable a good evaluation of sensory dysfunction. The relieving effect of sympathetic blockade is addressed, as well as the significance of autotomy and scratching behaviour after large injury, whether ethical rules are taken into account or not. Further, rat models with less dramatic injuries are described as useful tools for the study of neuropathic pain. Several classical techniques remain essential as tools of study but new state-of-the-art techniques are also emphasized. A very hot point is the question of opioid efficacy for relieving neuropathetic pain.