Basilar Invagination, Bone Regrowth, Chiari malformation, Clivus, Odontoid Process, Transoral Odontoidectomy

Purpose: Transoral odontoidectomy followed by occipito-cervical fixation is a widely used approach to relieve ventral compressions at the craniovertebral junction (CVJ). Despite the large amount of literature on this approach and its complications, no previous reports of odontoid process and clival regeneration following transoral odontoidectomy are present in the English literature. Methods: We report the case of odontoid process and clival regeneration following transoral odontoidectomy. Results: A 7 year-old boy presented with symptoms of brainstem and upper cervical spinal cord compression due to a complex malformation at the CVJ including a basilar invagination with Chiari malformation. A successful transoral microsurgical endoscopicassisted odontoidectomy extended to the clivus was performed. Clinical and radiological resolution of the CVJ compression was evident up to two years post-op, when the child had a relapse of some of the presenting symptoms and the follow-up CT and MRI scans showed a quite complete regrowth of the odontoid process, clival partial regeneration and recurrence of preoperative Chiari malformation. Conclusions: A resection of the odontoid down to the dentocentral syncondrosis and an accurate lateral removal of the bone surrounding the anterior tubercle of the Clivus is advised when an anterior CVJ decompression is required in children below 10 years of age. Powered