Neuro-cranio-vertebral syndrome related to coccygeal dislocation: A preliminary study.

Background: Neuro-cranio-vertebral syndrome (NCVS) includes a set of idiopathic diseases: Arnold-Chiari syndrome type 0,1 and 1.5, idiopathic scoliosis, and idiopathic syringomyelia. It is caused by the pathological traction transmitted by the filum terminale on the neuraxis. Considering that the filum terminale is inserted at sacrococcygeal level, it is logical to think that an alteration of this segment's anatomy, such as an anterior coccyx dislocation, can increase the tension exerted by the filum terminale on the neuraxis, which in turn triggers NCVS. Methods: We collected data from 372 patients with NCVS and 15 patients with coccygeal dislocation and NCVS from our database. We analyzed the relationship between the sacrococcygeal and intercoccygeal angles with signs, symptoms and associated diagnoses. T-tests for independent samples and linear regression were used for analysis (p <0.05). We describe the MRI findings and clinical features of NCVS caused by coccygeal dislocation and compare its prevalence with that of a sample without coccygeal dislocation. Results: 65% of the signs, symptoms, and imaging features were present in similar proportions in both samples. There was a similar prevalence of cerebellar tonsillar descent and scoliosis in both groups, whereas the incidence of syringomyelia differed. A sacrococcygeal angle between 89-110° prevails in cases of syringomyelia while an intercoccygeal angle between 90-140° prevails in cases with cerebellar tonsillar descent. Conclusions: The high clinical and radiological prevalence of coccygeal dislocation in patients with Neuro-cranio-vertebral syndrome suggests an association between them. The mechanism involved in coccygeal dislocation can directly influence the development of Neuro-cranio-vertebral syndrome.