Concurrent Ossification of the Posterior Atlantoaxial Interlaminar Membrane and Atlas Hypoplasia: A Case Report

Effect of C1 Single‐door Laminoplasty on Symptomatic Atlas Canal Stenosis

“…SACS is a rare disease that may challenge every spine surgeon. 2 , 4 , 5 , 13 , 14 , 15 , 16 This study introduced reduction of AAS, single‐door laminoplasty of atlas and atlantoaxial fusion in the treatment of SACS. We found this new method could not only completely reduce AAS but also fully enlarge the inner sagittal diameter of atlas, and achieve C1‐2 fusion satisfactorily.…”

“…SACS is a rare disease that may challenge every spine surgeon 2,4,5,13–16 . This study introduced reduction of AAS, single‐door laminoplasty of atlas and atlantoaxial fusion in the treatment of SACS.…”

“…According to the literature and our experiences, several pathologies including atlantoaxial subluxation (AAS), ossification of the transverse ligament, retro‐odontoid pseudotumor, basilar invagination and Os odontoideum may have contributed to the development of myelopathy. 4 , 5 , 6 , 7 Clinically significant myelopathy happened when the canal was further narrowed by dislocating dens, scar encroachment and malformed odontoid process. Congenital small atlas combined with degenerative factors leads to symptomatic myelopathy.…”

“…In contrast, people with a complete and small size of atlas alone may not develop symptomatic myelopathy, or developed symptomatic myelopathy at the age of more than 60 years, which suggests that the determining factor for C1 stenosis could be degenerative rather than congenital. According to the literature and our experiences, several pathologies including atlantoaxial subluxation (AAS), ossification of the transverse ligament, retro‐odontoid pseudotumor, basilar invagination and Os odontoideum may have contributed to the development of myelopathy 4–7 . Clinically significant myelopathy happened when the canal was further narrowed by dislocating dens, scar encroachment and malformed odontoid process.…”

Percutaneous full endoscopic C1 laminectomy for developmental atlantal stenosis with myelopathy: a case report of three cases and review of the literature

“…The occurrence of atlas developmental malformation is more common in patients with Chiari malformation, Down syndrome, Klippel-Feil syndrome, Noonan syndrome, Williams syndrome, diffuse idiopathic skeletal hyperostosis (DISH), atlanto-axial instability, and atlantoaxial subluxation with or without os odontoideum (4,5,(17)(18)(19)(20)(21)(22)(23)(24). Stenosis secondary of C1 without trauma and atlantoaxial instability is a possible pathophysiologic factor, which may be secondary to atlas hypoplasia, ossification of the posterior atlantoaxial membrane (PAAM) (20), or ossification of the transverse atlantal ligament (OTAL) (25) that lead to consistent space reduction of the spinal cord. The developmentally narrowed spinal canal of the atlas in minors is generally displayed as the inturning of a bifid posterior arch, partial atlas agenesis, or absence of the PAA (4,26-29).…”