Aim: The object of this case report is to report primary C1 arch stenosis as a cause of myelopathy in an ankylosing spondylitis patient.
Background: Myelopathy at the level of the atlas in ankylosing spondylitis is commonly caused by atlantoaxial or occipitocervical subluxation, retro-odontiod pannus formation, cranial settling/ basilar invagination, odontoid fracture. Myelopathic feature are often neglected and are attributed to sacroiliac and lumbar spine involvement initially in these patients.
Case report: A 54 years old patient with long-standing ankylosing spondylitis presented with history neck pain with restriction of neck movements, gradually progressive weakness and stiffening of all four limbs. On examination, the patient had myelopathic features. Computed tomography (CT) of cervical spine showed straightening of cervical spine with severe stenosis at the C1 and bamboo stick appearance of a spine. The Magnetic resonance imaging (MRI) showed cord compression and T2 cord signal changes at the C1 level. The patient underwent C2 laminectomy and C1 posterior arch excision in neutral prone position. Postoperatively, the patient demonstrated improved limbs activity with a reduction in the flexor spasm.
Conclusion: Primary C1 arch stenosis may be one of the causes of myelopathy in ankylosing spondylitis patients and timely diagnosis and intervention benefits the patient and reduces morbidity.