title: Cervical myelopathy associated with congenital C2/3 canal stenosis and deficiencies of the posterior arch of the atlas and laminae of the axis: case report and review of the literature.
abstract: METHODS
  A case report of a young male suffering progressive neurologic dysfunction associated with a previously unreported combination of structural bony abnormalities. A review of the literature is also presented.
  
  
  OBJECTIVE
  To describe a unique presentation of cervical myelopathy related to posterior deficiencies of the atlas and axis, and to report on the successful management of this case.
  
  
  BACKGROUND
  Cervical myelopathy from congenital canal stenosis is an uncommon presentation in the adolescent age group, especially affecting the C2/3 level. Aplasia of the atlas is a rare, although well-reported phenomena. Defects of the posterior elements of the axis are similarly uncommon. A combination of the 2 defects in the 1 patient has not previously been recorded.
  
  
  METHODS
  A 14-year-old Caucasian male with no history of trauma or neck pain presented with progressive cervical myelopathy over a 2-year period. Plain radiograph and computed tomography revealed congenital aplasia of the posterior arch of the atlas and bilateral cleft defects of the laminae of the axis resulting in a free floating C2 spinous process. Magnetic resonance imaging showed T1 and T2 signal abnormality at the C2-C3 level, with C2/3 congenital canal stenosis and mild disc protrusion.
  
  
  RESULTS
  The patient underwent a posterior decompression and lateral mass fixation at the C2/3 articulation to preserve maximal motion segments. At 12-month follow-up, the patient's cervical myelopathy had improved in terms of gait dysfunction and hemiparesis. Fusion was evident across the posterior lateral mass on radiologic investigation.
  
  
  CONCLUSIONS
  Posterior deficiencies of the atlas and axis are rare occurrences in isolation, let alone in the 1 patient. This report broadens the radiographic differential diagnosis of patients presenting with cervical myelopathy, which has been associated with congenital posterior C2 anomalies in only a handful of patients. Surgery is an appropriate option for these patients faced with progressive neurologic dysfunction.
authors.affiliation: University of New South Wales, and Department of Neurosurgery, Spine Unit, Prince of Wales Hospital, Sydney, Australia.
authors.forename: Anthony Minh Tien
authors.initials: AM
authors.lastname: Chau
authors.forename: Johnny Ho-Yin
authors.initials: JH
authors.lastname: Wong
authors.forename: Ralph Jasper
authors.initials: RJ
authors.lastname: Mobbs
mesh_terms: D000293:Adolescent; D001368:Axis, Cervical Vertebra / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology; D001270:Cervical Atlas / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000601:surgery; D019299:Decompression, Surgical; D020233:Gait Disorders, Neurologic / Q000209:etiology; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D007796:Laminectomy; D008279:Magnetic Resonance Imaging; D008297:Male; D010291:Paresis / Q000209:etiology; D011859:Radiography; D013117:Spinal Cord Compression / Q000151:congenital / Q000000981:diagnostic imaging / Q000473:pathology*; D013123:Spinal Fusion; D013130:Spinal Stenosis / Q000151:congenital / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome