- Department of Neurosurgery, Kagawa Rosai Hospital, Marugame City, Kagawa, Japan.
DOI:10.25259/SNI_822_2019Copyright: © 2020 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Masatoshi Yunoki. A surgical case of C1 arch stenosis: A case report and review of literature. 23-Feb-2021;12:71
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Background: Isolated symptomatic cervical stenosis of the atlas is quite rare; there have been 11 cases reported in literature.
Case Description: A 76-year-old male presented with myelopathy attributed to C1 arch stenosis. Neuroimaging studies revealed posterior atlas compression of the spinal cord. Following a cervical laminectomy involving excision of the arch of the atlas, and the patient’s symptoms resolved.
Conclusion: C1 stenosis resulting in cervical myelopathy due to posterior compression from the arch of the atlas is easily missed. Notably, C1 arch laminectomy may be very effective in resolving this entity.
Keywords: Atlas, Cervical myelopathy, Hypoplasia, Stenosis
Only 11 prior cases of symptomatic cervical stenosis due to C1 posterior arch compression have been reported in the literature.[
A 74-year-old male presented with a 6-month history of gait disturbance, and clumsy hands that had exacerbated over the past 2 months; there was no history of trauma. He exhibited a spastic gait, bilateral hyperactive deep tendon reflexes in the upper/lower extremities, and bilateral positive Hoffmann’s signs. Plain radiographs showed marked narrowing of the cervical spinal canal, while the axial and sagittal computed tomography (CT) scans revealed a hypoplastic but intact posterior arch of the atlas [
C1 anomaly and stenosis
It is well known that congenital anomalies occasionally involve the arch of atlas. In 2018, Hyun et al. reported 5.6% of such congenital lesions at C1 among their 3273 subjects.[
Clinical data for 12 total cases
With this case added, a total of 12 prior cases of C1 congenital stenosis resulting in myelopoathy all occurred in middle-aged Asian males.[
The threshold of a canal diameter
In the 12 patients cited, the average sagittal canal diameter at the level of atlas in symptomatic patients with C1 stenosis was <10 mm. On routine cervical MR, compression at C1 atlas level is readily established. Further, physicians dealing with such C1 disorders may readily establish the diagnosis on lateral cervical X-rays with careful observation of narrowed AP diameter based upon the spinolaminar line [
Explanation of spinolaminar line test. The C3–C2 spinolaminar line is drawn extending cranially up to C2. Then, this line is extended up to C1. (a) Example of normal cervical spine. The ventral aspect of the C1 lamina is posterior to this line. (b) Example of positive spinolaminar line test. Ventral lamina of C1 is anterior to this line.
For treating C1 stenosis, laminectomy or laminoplasty is typically effective.[
If there is a large inferior facet angle and/or subaxial ankylosis, as an anterior arch fracture may occur in up to 14.2% of cases follow a C1 laminectomy or laminoplasty initially be carefully considered.[
Symptomatic myelopathy attributed to C1 stenosis may be readily reversed with a decompressive procedure.
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