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

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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. These slides can be retrieved under Electronic Supplementary Material.

Floating Laminoplasty for the Treatment of Compressive Myelopathy Accompanied by C1 Posterior Ring Hypoplasia: A Technical Note and Case Series.

Posterior ring hypoplasia of the atlas (C1) is not common and in most cases is found by chance without symptoms. This disorder is sometimes accompanied by a mild C1-C2 instability or the presence of a space-occupying lesion such as ossification of posterior longitudinal ligament, pannus, or retro-odontoid pseudo-tumor, which are indications for surgery if symptomatic cord compression is present. A C1 posterior arch resection has been the procedure of choice but is associated with several fatal complications. We here present a novel posterior arch decompression technique that is relatively safer and easier and that involves mobilization and posterior translation of the posterior arch as a whole, similar to a vertebral body sliding osteotomy.