This article describes the successful surgical treatment of a case of damage to the inferior alveolar nerve, due to inadvertent extrusion of endodontic material into the mandibular canal. The accident was favoured by an anatomical variant of the nerve canal ending with a double mental foramen, already described in the literature. The complex surgical operation of uncertain outcome was dictated by neuralgia refractory to medical treatment, rather than hypoesthesia associated with compression of the nerve trunk. Problems related to loss of sensitivity and possible causes of nerve damage (traumatic, pathological and iatrogenic) are discussed.