成人ダウン症に発症した脊髄症に対して後頭骨軸椎固定術を行った1例

Occipitoaxial Fusion for Atlantoaxial Subluxation Associated with Down Syndrome. Case Report

　成人ダウン症候群患者に合併した環軸椎亜脱臼に後頭骨軸椎固定術を行った1例について報告する．転倒した際の擦過創で前医を受診した際，四肢痙性麻痺を認め脊髄症と診断された．C1/2の脊髄余裕空間（space available for spinal cord，SAC）は4.5mmと極度に狭小で，MRI上歯突起後方の脊髄は菲薄化していた．透視下に頚椎を牽引しながら軽度伸展位とし，後頭骨軸椎固定を行った．C1後弓は切除し，腸骨移植を行った．術後2年，階段歩行も可能となり，四肢の愁訴ならびに排尿困難感は消失した．

　We report the case of an adult patient with Down syndrome who developed cervical myelopathy and was successfully treated by occipitoaxial fusion. A 31-year-old woman went to another hospital for treatment of a skin injury sustained in a fall, and the physician there made a diagnosis of cervical myelopathy based on the presence of a gait disturbance, clumsy hands, and a urinary disturbance. A plain radiograph revealed anterior subluxation of the atlas with SAC in 4.5mm at the C1 level, and an MRI examination showed spinal canal stenosis with myelomalacia at the C1 level. Under general anesthesia, an attempt was made to reposition the atlas by distraction and extension of the patient's neck under fluoroscopic guidance. We then resected the posterior arch of C1 and fused the occipital bone to the axis with iliac bone. The patient had no complaints regarding her extremities or bladder function at the final follow-up examination 2 years after surgery, and there was no loss of correction in the fusion area.