Cervical Myelopathy Secondary to Atlanto-occipital Assimilation: The Usefulness of the Simple Decompressive Surgery
A 36-year-old male presented himself with a one-month history of numbness of all his fingertips in his left hand, hypesthesia, posterior neck pain, and left shoulder pain. The neurological examination upon his admission revealed marked restriction in the range of the left forward bending motion of his neck due to an electrical sensation that was running down his back and into his limbs (Lhermitte's sign) and that included a positive Hoffmann's sign.\nCervical plain film radiography and computed tomography (CT) revealed partial circumferential fusion of the anterior and posterior C1 arches with the basilar part of the occipital bone (complete anterior fusion and partial, asymmetrical posterior fusion) and incomplete block vertebrae on C2-3 (C2 vertebral arch and C3 lamina fusion on the left side) (). Cervical magnetic resonance imaging (MRI) revealed high signal intensity in the spinal cord on the T2 weighted images, which indicates spinal distress caused by the encroachment of the left C1 posterior arch and the left C2 vertebral arch on the neural canal (). The patient's symptoms were regar ded as the consequence of the encroachment of the bony element on the neural canal. There was also no occipitocervical instablility. Thus, the patient underwent posterior surgery for partial removal of his C1 left posterior arch and his C2 left vertebral arch to decompress his thecal sac.\nA day after the surgery, the numbness of the patient's fingertips, his hypesthesia, and Lhermitte's sign disappeared. The image of the decompression of the thecal sac was confirmed with a post-operative CT scan (). The absence of post-operative instablility was also confirmed.