Painful posttraumatic trigeminal neuropathy: a recently recognized entity.

A n unusual event recently occurred in the field of chronic orofacial pain. A new entity has been established through a few research papers and meetings of experts. Different specialists have known for some time that surgery and other traumatic events may injure the trigeminal nerve and provoke symptoms. Nerve damage may occur during Caldwell-Luc intervention, orthognathic mandibular advancement surgery, extrusion of root canal filling materials, implant surgery, and various traumatic events such as facial fractures and therapeutic radiation ; third molar removal is the most frequent cause. 1 Several branches of the mandibular or maxillary division of the trigeminal nerve could be involved, such as the infraorbital nerve, the superior alveolar nerves, and most frequently the lingual and inferior alveolar nerves. The signs and symptoms are similar to those in neuropathic pain conditions elsewhere in the body, with either negative signs and symptoms such as anesthesia or hypoalgesia and/or signs and positive symptoms such as hyperalgesia, dysesthesia, allodynia, and continuous burning sensations. There is also a chronologic relation between the beginning of these signs and symptoms and the actual traumatic event (see reviews). 2,3 Because it has been poorly documented , both the incidence and the gravity of the patients' problems have often been underestimated. Not surprisingly, many different names have been used, including chronic injury– induced orofacial pain, anesthesia dolorosa, posttraumatic neuralgia or neuropathy, secondary trigeminal neuralgia from facial trauma, neuropathic orofacial pain, numb chin syndrome, and peripheral painful traumatic trigemi-nal neuropathy. Until recently, these clinical cases were not identified as belonging to a single entity, as can be inferred from the insufficient description 2 given by the two main classification systems. 4,5 Recently , the entity has gained recognition after the recent publication of some well-documented papers and the most recent proposal of the classification committee of the International Headache Society (IHS), which proposed the term " painful posttaumatic trigeminal neuropathy " (PPTTN). 6 The recognition of this entity can be described as a three-phased approach, as outlined in the following: 1. Identification of PPTTN as an independent entity: This was suggested by a multicenter study which indicated that the 20 cases of PPTTN found among 245 cases of chronic orofacial pain tended to cluster. 7 This was in line with a recent study performed on 328 patients with chronic orofacial pain that indicated that over 12% of the cases were PPTTN. 8 These two studies pointed …