title: Incidence of basilar invagination in patients with tonsillar herniation? A case control craniometrical study.
abstract: A retrospective case-control study based on craniometrical evaluation was performed to evaluate the incidence of basilar invagination (BI). Patients with symptomatic tonsillar herniation treated surgically had craniometrical parameters evaluated based on CT scan reconstructions before surgery. BI was diagnosed when the tip of the odontoid trespassed the Chamberlain's line in three different thresholds found in the literature: 2, 5 or 6.6 mm. In the surgical group (SU), the mean distance of the tip of the odontoid process above the Chamberlain's line was 12 mm versus 1.2 mm in the control (CO) group (p<0.0001). The number of patients with BI according to the threshold used (2, 5 or 6.6 mm) in the SU group was respectively 19 (95%), 16 (80%) and 15 (75%) and in the CO group it was 15 (37%), 4 (10%) and 2 (5%).
authors.affiliation: Departamento de Neurologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Andrei F
authors.initials: AF
authors.lastname: Joaquim
authors.affiliation: Departamento de Neurologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Yvens Barbosa
authors.initials: YB
authors.lastname: Fernandes
authors.affiliation: Departamento de Neurologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Roger N
authors.initials: RN
authors.lastname: Mathias
authors.affiliation: Departamento de Neurologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Ulysses C
authors.initials: UC
authors.lastname: Batista
authors.affiliation: Departamento de Neurologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Enrico
authors.initials: E
authors.lastname: Ghizoni
authors.affiliation: Departamento de Neurologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: Helder
authors.initials: H
authors.lastname: Tedeschi
authors.affiliation: Orthopaedic Surgery, Northwestern University, Chicago, Illinois, USA.
authors.forename: Alpesh A
authors.initials: AA
authors.lastname: Patel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002508:Cephalometry / Q000379:methods*; D004677:Encephalocele / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009777:Occipital Bone / Q000002:abnormalities / Q000473:pathology; D009809:Odontoid Process / Q000473:pathology; D010985:Platybasia / Q000473:pathology*; D012016:Reference Values; D012189:Retrospective Studies; D019291:Skull Base / Q000473:pathology; D014057:Tomography, X-Ray Computed; D055815:Young Adult