Atlas hypoplasia as a cause of high cervical myelopathy

Abstract

A high cervical myelopathy due to atlas hypoplasia is described in a 56-year-old man; the condition caused marked segmental compression of the spinal cord. A remarkable neurological recovery followed decompressive laminectomy of the atlas and adjacent regions. The authors discuss the embryology and etiology of this anomaly.

Atlas Hypoplasia Manifesting as Myelopathy in a Child. Case Report.

“…5) Atlas stenosis may be caused by premature fusion of the two neurocentral and one posterior cartilaginous synchondroses during the 6th week to 4th month of gestation. 3,7) As a result, the three primary ossification centers among these three synchondroses may not grow away from each other. 1,3,7,9) Continuous growth of the lateral sides to the fused posterior cartilaginous synchondrosis would result in a thick posterior arch of the atlas, as shown in our patient.…”

“…3,7) As a result, the three primary ossification centers among these three synchondroses may not grow away from each other. 1,3,7,9) Continuous growth of the lateral sides to the fused posterior cartilaginous synchondrosis would result in a thick posterior arch of the atlas, as shown in our patient. The median cleft of the atlas found in a brother of our patient with atlas hypoplasia, if not coincidence, suggests that common genetic factors are involved in the two different forms of congenital malformation of the atlas.…”

“…4,13) All reported cases, including ours, involving atlas stenosis with a complete posterior arch occurred in Asian people, predominantly in men, indicative of ethnic association and sex dominance. 3,4,6,[8][9][10][11]13) The cases of brothers with atlas hypoplasia suggested a genetic factor. 9) Our case shows that myelopathy may be evoked even in a young patient with atlas hypoplasia with complete posterior arch and in the absence of spondylotic change.…”

“…3,4,6,[8][9][10][11][12][13] All patients had myelopathic symptoms, except for one of unknown age and sex who had occipital neuralgia. 12) The patients were aged 38, 54, 55, 69, 73, 75, 77, 80, and 81 years.…”

“…Atlas hypoplasia with complete posterior arch is a rare congenital abnormality, exclusively occurring in Asian people, 3,4,6,[8][9][10][11]13) except for one case the details of which are unknown. 12) Clinical manifestation characteristically occurs late in adulthood when cervical spondylotic changes become apparent.…”