Craniovertebral junction anomalies in inherited disorders: part of the syndrome or caused by the disorder?

Patterns of skeletal abnormality at the craniovertebral junction in the normal population and in syndromes such as Down, Morquio etc, are compared and the recent embryological data and comparative anatomy reviewed. The authors' view based on their own clinical and radiological experience is that the os odontoideum is the product of excessive movement at the time of ossification of the cartilaginous dens and is exactly analogous to the unfused Type II odontoid fracture. True hypoplasia of the odontoid peg is part of a wider segmentation defect associated with Klippel Feil, occipitalised atlas and/or basilar invagination; it is hardly ever associated with instability.

Craniocervical abnormalities in osteogenesis imperfecta: genetic and molecular correlation.

Basilar impression (BI) assessed by either plain lateral skull radiograph or computerized tomography (CT) sagittal reconstruction of the craniocervical junction is a common finding occurring in 25% of subjects with osteogenesis imperfecta (OI). It appears to occur with highest frequency in a group of subjects with OI type IV B, i.e. patients with mild/moderate liability to fractures, normal sclerae but dentinogenesis imperfecta. Neurologic signs indicating compression of posterior fossa structures occur predominantly in subjects with BI and OI type IV. Screening is recommended for all patients with OI but particularly OI type IV B.

Impressäo basilar familial em 10 casos operados / Familial basilar impression in 10 operated cases

Säo analisados os resultados clínicos e radiolóicos de 12 pais e 40 irmäos de 10 pacientes operados de impressäo basilar e malformaçäo de Arnold-Chiari. É feita revisäo de literatura sobre a ocorrência familial da impressäo basilar

MR imaging of familial basilar impression.

Basilar impression was found in three members of one family. The mother showed an asymptomatic deformity, her eldest son complained of headache, drop-attacks, nystagmus, unilateral ophthalmoplegia, and ataxia; the middle son presented with headache, nystagmus, and hemiparesis. Magnetic resonance (MR) imaging demonstrated convexobasia of various degrees with elevation of the upper spine and malformation of the occipital bone. The medulla oblongata and the pons were flattened and dislocated backward in two cases. Chiari malformation was present in one case and mild hydrocephalus in another. A comparison of MR with CT imaging demonstrates some advantages of the former method in the assessment of the neural structures directly involved in basilar impression.

Basilar impression in osteogenesis imperfecta. A report of three cases in one family.

Basilar impression is a well-recognised though rare complication of osteogenesis imperfecta. Three patients, all members of the same family, with advanced basilar impression complicating osteogenesis imperfecta tarda, are described. The clinical features in these cases illustrate the natural history of this condition: from asymptomatic ventricular dilatation, through the foramen magnum compression syndrome, to death from brain-stem compression. The radiological criteria on which the diagnosis is based, are defined. Review of the literature reveals only seven previously documented cases, all in patients with mild forms of osteogenesis imperfecta. The unusually low incidence of basilar impression in osteogenesis imperfecta and its apparent restriction to patients with mild forms of the disease is discussed. The examination of close relatives of patients with basilar impression and osteogenesis imperfecta is emphasised in order to anticipate the onset of severe neurological complications.

Contribution to the etiology of spina bifida cystica.

Authors report of bone anomalies found out by plain X-ray examination in 61 mothers and 40 fathers of children with spina bifida cystica. There was ascertained hyper-pneumatisation of skull bones 18 times, platybasia or basilar impression 15-times, spina bifida occulta 11-times and deformation of lumbosacral vertebrae 8-times. Only in 49 parents of handicapped children the roentgenological picture of their skeleton was physiological. In comparison with the control group of 100 persons chosen by random access the incidence of skeleton anomalies of parents of children with congenital defects of the neural tube was significantly higher.

[Familial occurrence of basilar impression]. / Ocorrência familiar de impressão basilar.

The authors studied nine members of the same family; two among them received surgical treatment for basilar impression and Arnold-Chiari malformation. In the other members of the family, several signs and symptoms of central nervous disease were observed. All patients had the apex of the odontoid apophysis above McGregor's line, 4 mm in the case 9, and 10 mm or more in the others.