Chiari malformation corresponds to the herniation of cerebellar tonsils into the foramen magnum resulting in obstruction of cerebrospinal fluid circulation, which may eventually lead to the formation of an intramedullary cavity called syringomyelia.

Chiari and syringomyelia can be responsible of variable symptoms, based on which neurosurgeons might propose surgical treatment. Yet, there is no properly developped and validated patient reported outcome measure (PROM) to assess the clinical severity of Chiari malformation and/or syringomyelia. The lack of such evaluation tool is a major issue to determine the optimal therapeutic strategy and to achieve a standardized and reproducible follow-up.

Chiari malformation corresponds to the herniation of cerebellar tonsils into the foramen magnum resulting in obstruction of cerebrospinal fluid circulation, which may eventually lead to the formation of an intramedullary cavity called syringomyelia.

Chiari and syringomyelia can be responsible of variable symptoms, based on which neurosurgeons might propose surgical treatment. Yet, there is no properly developped and validated patient reported outcome measure (PROM) to assess the clinical severity of Chiari malformation and/or syringomyelia. The lack of such evaluation tool is a major issue to determine the optimal therapeutic strategy and to achieve a standardized and reproducible follow-up. The project will consist of two successive phases: a survey design of the questionnaire with small selected groups of patients; a monocentric pilot study on a limited population; The purpose of the development study is to produce a first version of the PROM based on proposed items written by experts and tested with volunteer patients (n = 10-20) within the framework of " focus groups" followed by cognitive debriefings. These items will explore various dimensions of the functional impact of Chiari malformation and syringomyelia (pain, motor disability, sphincter disorders, quality of life, etc.). The pilot study will test this 1st version of the questionnaire on a limited population of patients (n = 40) within the CRMR C-MAVEM of Bicêtre hospital to produce a final version. This work will be supplemented subsequently by a multicenter study allowing to validate a simple and reproducible evaluation tool in order to ensure the follow-up of patients with a Chiari malformation and/or syringomyelia and to measure surgical outcome.

Inclusion Criteria:

Criteria common to all subjects included in the study

• Age > 18 years
• Subject understanding French Patients included in Phase I
• Subject with signed informed consent Patients included in phase II
• Patient not opposed to study participation

Patients Chiari only group:

• Isolated descent of cerebellar tonsils > 5 mm below McRae's line (no associated syringomyelia)

Patients syringomyelia only group:

• Presence of an intramedullary fluid cavity secondary to circulatory disturbance of cerebrospinal fluid of non foraminal origin (no Chiari)

Patients Chiari with Syringomyelia group:

• Presence of Chiari malformation (tonsils > 5 mm below McRae's line) AND foraminal syringomyelia.

Exclusion Criteria:

• Insufficient command of French
• Minor or protected adult (guardianship, curatorship, safeguard of justice)
• Diagnosis of Chiari and/or syringomyelia not proven by an MRI scan
• Pregnant or breast-feeding

The development of a questionnaire for self-assessment of the clinical impact of a pathology necessarily requires the involvement of the patients concerned. In particular, it is important that the clinical heterogeneity of the patients concerned is represented. The study population will therefore be patients with Chiari malformation, whether or not they have associated syringomyelia, and whether or not they have foraminal syringomyelia. They will be recruited via neurosurgical centers belonging to the C-MAVEM (Chiari, syringomyelia and vertebro-medullary malformations) network of rare disease reference centers for Chiari malformations and syringomyelia, and with the help of the main patient association (APAISER).