Ventral Cervicomedullary Junction Compression Secondary to Condylus Occipitalis (Median Occipital Condyle), a Rare Entity

Abstract

OBJECTIVE: Condylus occipitalis is presented in postmortem anatomic studies. There is no clinical study in the literature. Myelopathy due to anomalies of the craniovertebral junction is rare in neurosurgical practices. To our knowledge, myelopathy due to condylus occipitalis has not been reported before. Deaths of two cases were previously reported, but these were not live cases. METHODS: We describe the case of a 40-year-old woman presenting with progressive myelopathy related to condylus occipitalis located in the anterior foramen magnum region. RESULTS: Magnetic resonance imaging and computed tomography showed the condylus occipitalis, marked stenosis of the spinal canal at the level of the atlas, with cord compression and evidence of myelopathy. We performed posterior decompression without fusion and duraplasty. Because the cervicomedullary compression syndrome was not resolved, a transoral decompression could not be done owing to pulmonary insufficiency. CONCLUSIONS: This unique clinical article (a live case), not anatomic, presents a very rare abnormality of the craniovertebral junction. Myelopathy is a very important complication of this congenital craniovertebral junction abnormality. Posterior decompression seems not to be effective for myelopathy due to condylus occipitalis. In our opinion, anterior decompression is needed in this condition. A larger series will be needed to better define its role in the management of this anomaly.