Chiari type I malformations in adults: a morphometric analysis of the posterior cranial fossa.

OBJECTIVE Chiari type I malformation (CMI) is a congenital disorder characterized by caudal displacement of the cerebellar tonsils through the foramen magnum into the spinal canal. Recent studies suggest that overcrowding in the posterior cranial fossa (PCF) because of underdeveloped bony structures in the intrauterine life is the main cause of this malformation. For this reason, the authors want to contribute to the current literature, which focuses on bone abnormalities in the PCF in patients with CMIs. METHODS We examined a retrospective cohort of 60 adult patients with CMIs, and multiple measurements were made on magnetic resonance imaging. The results were compared to 30 healthy adult control subjects. Mann-Whitney U test was used as a statistical method. RESULTS All measurements except mean anteroposterior diameter of the foramen magnum were reduced in patients compared to control. An increase in the anteroposterior mid-sagittal distance of the foramen magnum in patients reached statistically significant difference compared to control. All patients had tonsillar herniation at least 5 mm below the plane of the foramen magnum. Chiari type I malformation in this study was associated with syringomyelia in 46 patients. CONCLUSION This study with a limited number of patients suggests that the bony components of the PCF are not developed fully, supporting the current concept that CMI is a disorder of the para-axial mesoderm.

[1]  B Williams,et al.  On the Pathogenesis of Syringomyelia: A Review 1 , 1980, Journal of the Royal Society of Medicine.

[2]  J. Berciano,et al.  Basichondrocranium anomalies in adult Chiari type I malformation: a morphometric study , 1990, Journal of the Neurological Sciences.

[3]  M C Speer,et al.  Chiari I malformation redefined: clinical and radiographic findings for 364 symptomatic patients. , 1999, Neurosurgery.

[4]  J. Hahn,et al.  Symptomatic Chiari malformation in adults: a new classification based on magnetic resonance imaging with clinical and prognostic significance. , 1991, Neurosurgery.

[5]  T. Milhorat,et al.  Dysesthetic pain in patients with syringomyelia. , 1996, Neurosurgery.

[6]  W. J. Oakes,et al.  Analysis of the Posterior Fossa in Children with the Chiari 0 Malformation , 2001, Neurosurgery.

[7]  Salem Sn.  RECURRENT CEREBRAL ISCHAEMIA. , 1964 .

[8]  D. Ferriero,et al.  Pediatric Chiari I malformations , 1999, Neurology.

[9]  G. du Boulay,et al.  The mechanism of hydromyelia in Chiari type 1 malformations. , 1974, The British journal of radiology.

[10]  Akira Hakuba,et al.  Pathogenesis of Chiari malformation : a morphometric study of the posterior cranial fossa , 1997 .

[11]  A D Dayan,et al.  Pathogenesis of syringomyelia. , 1972, Lancet.

[12]  T. Milhorat,et al.  Pathological basis of spinal cord cavitation in syringomyelia: analysis of 105 autopsy cases. , 1995, Journal of neurosurgery.

[13]  F. Maroun,et al.  The Chiari Malformation in Adults , 1975, Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques.

[14]  J. Tew,et al.  Chiari I malformation: classification and management. , 1995, Neurosurgery.

[15]  J. Tew,et al.  Chiari I malformation: classification and management. , 1995 .

[16]  T. Milhorat,et al.  Clinicopathological correlations in syringomyelia using axial magnetic resonance imaging. , 1995, Neurosurgery.

[17]  Christopher J. Brown,et al.  Arterial pulsation-dependent perivascular cerebrospinal fluid flow into the central canal in the sheep spinal cord. , 1997, Journal of neurosurgery.

[18]  J. Hahn,et al.  Chiari malformation presenting in adults: a surgical experience in 127 cases. , 1983, Neurosurgery.

[19]  L. Stovner,et al.  Posterior cranial fossa dimensions in the Chiari I malformation: Relation to pathogenesis and clinical presentation , 2004, Neuroradiology.

[20]  J. Birns.  An Unusual Form of Laryngeal Paralysis Associated with Arnold-Chiari Malformation , 1984, The Annals of otology, rhinology, and laryngology.

[21]  M. Kraut,et al.  Asymptomatic Chiari Type I malformations identified on magnetic resonance imaging. , 2000, Journal of neurosurgery.

[22]  Committee on Hearing and Equilibrium. Report of Subcommittee on Equilibrium and its Measurement. Meniere's disease: criteria for diagnosis and evaluation of therapy for reporting. , 1972, Transactions - American Academy of Ophthalmology and Otolaryngology. American Academy of Ophthalmology and Otolaryngology.

[23]  S. Weig,et al.  Recurrent syncope as the presenting symptom of Arnold‐Chiari malformation , 1991, Neurology.

[24]  G. du Boulay,et al.  The normal position of the cerebellar tonsils as demonstrated by myelography. , 1973, Journal of neurosurgery.

[25]  A. Elster,et al.  Chiari I malformations: clinical and radiologic reappraisal. , 1992, Radiology.

[26]  H. Chiari.  Concerning alterations in the cerebellum resulting from cerebral hydrocephalus. 1891. , 1987, Pediatric neuroscience.

[27]  W. Schady,et al.  The incidence of craniocervical bony anomalies in the adult Chiari malformation , 1987, Journal of the Neurological Sciences.

[28]  D. Gelb,et al.  Presentation of type I Chiari malformation after head trauma. , 1988, Neurosurgery.

[29]  A. Sclafani,et al.  Chiari-I malformation associated with asymmetric sensorineural hearing loss. , 1992, The Journal of Otolaryngology.

[30]  W. House.  Meniere's disease: management and theory. , 1975, Otolaryngologic clinics of North America.

[31]  R. Friede,et al.  Chronic tonsillar herniation , 1976, Acta Neuropathologica.

[32]  D. Mikulis,et al.  Variance of the position of the cerebellar tonsils with age: preliminary report. , 1992, Radiology.

[33]  T H Shawker,et al.  Pathophysiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils. Implications for diagnosis and treatment. , 1994, Journal of neurosurgery.

[34]  G. Bejjani,et al.  Definition of the adult Chiari malformation: a brief historical overview. , 2001, Neurosurgical focus.

[35]  L. Stovner,et al.  Sinus arrhythmia and pupil size in Chiari I malformation: evidence of autonomic dysfunction. , 1993, Functional neurology.

[36]  W. Ball,et al.  Chiari I malformation: from Dr Chiari to MR imaging. , 1995, Radiology.

[37]  I. Pereiró,et al.  Acute respiratory failure as the first sign of Arnold-Chiari malformation associated with syringomyelia. , 1995, The European respiratory journal.

[38]  T. Milhorat,et al.  Stenosis of central canal of spinal cord in man: incidence and pathological findings in 232 autopsy cases. , 1994, Journal of neurosurgery.

[39]  J. Stears,et al.  Resolution of syringomyelia and Chiari I malformation by ventriculoatrial shunting in a patient with pseudotumor cerebri and a lumboperitoneal shunt. , 1988, Neurosurgery.

[40]  K. Sartor,et al.  Position of Cerebellar Tonsils in the Normal Population and in Patients with Chiari Malformation: A Quantitative Approach with MR Imaging , 1985, Journal of computer assisted tomography.

[41]  J. Miller,et al.  Noncommunicating syringomyelia following occlusion of central canal in rats. Experimental model and histological findings. , 1993, Journal of neurosurgery.

[42]  W. Gardner,et al.  The surgical treatment of Arnold-Chiari malformation in adults; an explanation of its mechanism and importance of encephalography in diagnosis. , 1950, Journal of neurosurgery.