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Introduction: Arnold Chiari Malformation Type II can be associated with basilar invagination through an elongated retroflexed odontoid process (dens axis). Traditionally, decompression surgery has been performed transorally under microscopic vision or via transcutaneous latero-cervical/posterior approaches. Endoscopic approaches were introduced a few years ago.
Case report: We report of an eleven-year-old girl with Arnold Chiari Malformation Type II who had undergone surgery eight years ago for posterior cranial fossa decompression at the department of neurosurgery. At that time, an external transcutaneous median approach was performed to resect the posterior arch of the atlas. The patient now presented with the initial symptoms of brainstem compression as a result of an elongated retroflexed odontoid process and craniocervical instability. Surgical technique: An endoscopic transoral/transnasal approach was chosen for the resection of the dens.
Conclusion: Endoscopic surgery was successful and the complete resection of the dens was achieved without any complications. In a second intervention, orthopaedic surgeons performed cranio-cervical arthrodesis.