Prise en charge du schwannome malin du nerf dentaire inferieur

Le schwannome malin est une tumeur des gaines nerveuses développée aux dépens des cellules de Schwann. Il est extrêmement rare dans la région cervico-faciale, et surtout à la mandibule. L'intérêt de cette présentation est qu'elle a permis de mettre en évidence les difficultés de prise en charge de cette tumeur. Nous rapportons le cas d'une patiente de 60 ans qui avait subi en avril 2018 à la clinique mutualiste de Cotonou une résection interruptrice de l'hémimandibule droite pour un schwannome malin du nerf dentaire inférieur droit. Il y a eu récidive 4 mois après la résection. La revue de littérature faite à l'occasion de la présentation de ce cas avait mis en exergue les réelles difficultés diagnostiques et thérapeutiques de cette tumeur. C'est une tumeur agressive avec un taux élevé de métastases et de récidives locales. Le schwannome malin du nerf dentaire inférieur est de pronostic sombre car, en dépit de la résection chirurgicale, seule option thérapeutique dans notre contexte, il y a eu récidive au bout de 4 mois

Incidence and risk factors for nerve injuries in mandibular third molar surgery

Background: The inferior alveolar (IAN); lingual (LN) and long buccal nerves (LBN) are the three terminal branches of the trigeminal nerve which are susceptible to injury during surgical extraction of impacted mandibular third molars. While it is not always possible to accurately predict the patients that will be affected with these complications; understanding and identifying the risk factors may allow the adoption of appropriate technique and expertise for specific cases. We embarked on this study to document the incidence and duration of injury to the inferior alveolar nerve (IAN); lingual nerve (LN) and long buccal nerve (LBN) following the operative removal of impacted mandibular third molars and to identify the associated radiographic and operative risk factors. Method: Pre- and postoperative neurosensory tests were performed for seventy nine patients who had surgical extraction of unilateral impacted mandibular third molars to determine the incidence and duration of complicating nerve injuries. The risk factors for nerve injury were determined among the radiographic variables and documented operative events. Results: The incidence reported were 6.6for IAN; 2.6for LN and 4.0for LBN; all but one of the nerve injuries resolved within 2 weeks. Depth of impaction (Pellet Gregory Level C) and linguo-version were the significant risk factors for IAN and LN injuries respectively while no risk factors was detected for LBN injury. Some significant operative events were associated with nerve injuries Conclusion: Nerve injury in third molar surgery can be predicted based on some radiographic risk factors and some unforeseen intraoperative events. Most of the injuries are transitory in nature