Post-operative regression of retro-odontoid pseudotumors treated with and without fusion

  • Kazuyoshi Kobayashi
  • Shiro Imagama
  • Kei Ando
  • Yoshihiro Nishida
  • Naoki Ishiguro
Original Article



Retro-odontoid pseudotumor is common in elderly people and is a cause of cervical myelopathy. The goal of the study was to investigate surgical procedures, outcomes, and post-operative spontaneous regression of posterior cervical retro-odontoid pseudotumors.


The subjects were 29 patients who underwent surgery for myelopathy due to a retro-odontoid pseudotumor around the craniocervical region at 9 facilities and were followed-up for an average of 54 months (range 12–96 months). Data were collected in a multicenter review of a retrospective database. Comparisons were performed between cases treated with and without fusion.


The JOA recovery rate at final follow-up did not differ significantly between the fusion (n = 17, including all 15 patients with atlantoaxial subluxation) and non-fusion (n = 12) groups. However, pseudotumor regression was significantly more frequent in the fusion group (100% vs. 42%, p < 0.01). In all patients, regression cases had significantly higher rates of contrast enhancement of the pseudotumor on pre-operative T1 gadolinium-enhanced MRI (68% vs. 14%, p = 0.013) and of JOA recovery (50% vs. 30%, p < 0.01).


Regression of pseudotumor occurred in all cases treated with fusion surgery. There was a significant difference in pseudotumor regression with or without fusion, and regression was significantly related to gadolinium enhancement on MRI. Therefore, it is preferable to use fusion surgery for a retro-odontoid pseudotumor that shows contrast enhancement, even if there is no apparent instability pre-operatively.

Graphical abstract

These slides can be retrieved under Electronic Supplementary Material.


Retro-odontoid pseudotumor Atlantoaxial instability Occipitocervical fusion Posterior decompression Spinal fusion Gadolinium-enhanced MRI 



Funding was from institutional sources only.

Compliance with ethical standards

Conflict of interest

None of the authors have a conflict of interest.

Supplementary material

586_2018_5573_MOESM1_ESM.pptx (1.5 mb)
Supplementary material 1 (PPTX 1524 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Orthopaedic SurgeryNagoya University Graduate School of MedicineNagoyaJapan
  2. 2.Department of Orthopaedic SurgeryNagoya University Graduate School of MedicineAichiJapan

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