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



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.

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Correspondence to Shiro Imagama.

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Kobayashi, K., Imagama, S., Ando, K. et al. Post-operative regression of retro-odontoid pseudotumors treated with and without fusion. Eur Spine J 27, 3105–3112 (2018).

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