A cervical myelopathy caused by invaginated anomaly of laminae of the axis in spina bifida occulta with hypoplasia of the atlas: case report

A case report and review of previous literature are presented. The objective of this manuscript was to report a case of cervical myelopathy caused by invaginated anomalous laminae of the axis in a spina bifida occulta patient with hypoplasia of the arch of the atlas and to discuss the etiology of this disease. To the authors' knowledge, few cases of cervical myelopathy due to invaginated anomalous laminae of the axis have been reported, none of which is combined with hypoplasia of the arch of atlas. Treatment was surgical removal of the invaginated laminae. The patient's history, clinical examination, imaging findings, and treatment were reported, and the etiology was discussed. Characteristic findings were revealed from imaging studies and multiplane reconstruction of the computed tomography images. The patient was treated with a posterior decompressive operation based on the images. A rapid improvement was observed after the surgery, and the patient's neurology was completely restored 1 month later. We reported a rare characteristic anomaly of the laminae of the axis with hypoplasia of the posterior arch of atlas. A multiplane reconstruction of the computed tomography images was very necessary for treatment of this case. Possible causes of this anomaly may be the failure of ossification or fusion of the embryological term, whereas invagination of the osteophyte may be associated with the traction of the dense fibrous band during growth and development. Surgical removal of the laminae could result in a satisfactory outcome.