Retro-Odontoid Pseudotumor Without Radiographic Instability with Congenital C1 Assimilation and C2-C3 Fusion

Abstract

Case: The authors present a case of retro-odontoid pseudotumor (ROP) with congenital C1 assimilation and C2-C3 block vertebra without radiological instability who presented with cervical myelopathy with spastic quadriparesis. The patient was managed with occipitocervical fusion and C1 laminectomy. She had rapid neurological recovery in 3 months postoperatively and at 2 years had complete resolution of the retro-odontoid mass. Conclusion: C1 assimilation without apparent radiographic instability as a cause of ROP is underappreciated. This case report and review of literature highlight that C1 assimilation and C2-C3 fusion can lead to ROP even in the absence of apparent radiographic instability with posterior atlantoaxial fusion alone providing good results.

A case of nonrheumatoid retro-odontoid pseudotumor in Klippel-Feil syndrome with C1 occipitalization

“…[ 3 , 7 ] Such cases are usually young and present with neurological symptoms, but this case is interesting because it was an elderly person who presented with ROPT. ROPT has been reported with or without atlantoaxial instability[ 1 , 2 , 4 ] [ Table 1 ]. Some reports advocate a combination of indirect decompression and immobilization in similar cases.…”

“…Buttiens et al, [1] 2018 67 Female C1-C fusion Yes Gandbhir et al, [2] 2021 NA NA O-C fusion Yes Lagares et al, [4]…”