Chiari malformation and sleep related breathing disorders.
OBJECTIVE: To estimate the frequency, mechanisms and predictive factors of sleep apnoea syndrome (SAS) in a large group of children and adults with type I (CMI) and II (CMII) Chiari malformation (CM). BACKGROUND: The anatomical and functional integrity of both respiratory circuits and lower cranial nerves controlling the upper airway is necessary for breathing control during sleep. These latter structures may be altered in CM, and a few investigations have reported CM related sleep disordered breathing. METHODS: Forty-six consecutive unrelated patients with CM (40 CMI, six CMII), of which 20 were children (eight males) and 26 were adults (12 males), underwent physical, neurological and oto-rhino-laryngoscopic examination, MRI and polysomnography. RESULTS: SAS was present in 31 (67.4%) of the patients with CM (70% of CMI, 50% of CMII, including mainly children). Sixty per cent of children with CM exhibited SAS, including 35% with obstructive (OSAS) and 25% with central (CSAS) sleep apnoea syndrome. SAS was observed in 73% of CM adults (57.7% OSAS, 15.4% CSAS). Severe SAS was found in 23% of CM adults. Multiple regression analysis revealed that age, type II Chiari and vocal cord paralysis predicted the central apnoea index. CONCLUSION: SAS is highly prevalent in all age groups of patients suffering from CM. CSAS, a rare condition in the general population, was common among the patients with CM in our study. Sleep disordered breathing associated with CM may explain the high frequency of respiratory failures observed during curative surgery of CM. Our results suggest that SAS should be systematically screened for in patients with CM, especially before surgery. (+info)
Validation of the ovine fetus as an experimental model for the human myelomeningocele defect.
PURPOSE: To produce a myelomeningocele-like human defect in the ovine fetus and validate this experimental model in our population. METHODS: A prospective study on 12 pregnant sheep of a crossed Hampshire/Down breed where a spinal defect was surgically created between Day 75 and Day 77 after conception. The technique consisted of a hysterotomy with exposure of fetal hind limbs and tail up to the mid spine. Fetal skin, paravertebral muscles, and 4 posterior spinal arches were excised, exposing the spinal cord. Duramater was opened and the medulla was incised until the medullar canal. Animals were euthanized at 139 days of gestation for fetal evaluation. The central nervous system was submitted to post-mortem magnetic resonance imaging (MRI) and the spine was submitted to pathological examination. RESULTS: The defect was created in 13 fetuses and 5 survived. Mean gestational age at necropsy was 121.6 days (varying from 93 to 145 days). Macroscopically, the defect was present in 4 cases. Microscopy revealed a flattened medulla with disappearance of the medullar canal and disruption of normal medullar architecture with neuronal apoptosis and/or fusion of the piamater and duramater. The MRI showed herniation of the cerebellum into the cervical canal and syringomyelia. CONCLUSIONS: The surgically produced defect mimics the defect found in the human fetus, including the Arnold-Chiari malformation. Post-mortem MRI was used for the first time in our study and proved an excellent alternative for demonstrating the cerebellar herniation. We standardized the technique for creating the defect in our population. (+info)
Regression of syringomyelia and tonsillar herniation after posterior fossa arachnoid cyst excision. Case report and literature review.
BACKGROUND: Some reports have documented posterior fossa cysts resulting in syringomyelic obstruction of cerebrospinal fluid (CSF) flow caused by cyst displacement within the foramen magnum. Rarely the syringomyelia is caused by acquired Chiari malformation due to a retrocerebellar arachnoid cyst. OBJECTIVE: To report the case of a 38-year-old man with hydrocephalus and syringomyelia, who was found to have a Chiari malformation secondary to a posterior fossa arachnoid cyst. After endoscopic third ventriculostomy, the patient was submitted to foramen magnum decompression and arachnoid cyst removal that were followed by resolution of both the Chiari malformation and the syringomyelia. DISCUSSION: In most published cases the syringomyelia has been attributed to obstruction of CSF flow at the foramen magnum by the arachnoid cyst itself. There is only one previous report of a posterior fossa arachnoid cyst producing tonsillar descent and syringomyelia. CONCLUSIONS: Posterior fossa arachnoid cysts can result in acquired Chiari malformation and syringomyelia. In our view, the management of these patients should be directed at decompressing the foramen magnum and include the removal of the walls of the coexistent arachnoid cyst as it seems to be the crucial factor that accounts for the development of the syringomyelia that these patients present. (+info)
Duraplasty in the posterior fossa using a boat-shaped sheet of expanded polytetrafluoroethylene.
Application of sutures between expanded polytetrafluoroethylene (ePTFE) dural substitutes and the dura mater is often frustrating in posterior fossa surgery because of the difficulty in holding the elastic graft in a deep and narrow field. To resolve this problem, we have developed a boat-shaped graft made from a triangular ePTFE sheet by pinching each angle using a suture. Formation of standing edges of the sheet facilitates holding of the flaps for secure and more rapid suturing than the conventional approach using a flat sheet. (+info)
Chiari 1 malformation with syringomyelia: correlation of phase-contrast cine MR imaging and outcome.
AIM: This study was designed to determine the hemodynamics of cerebrospinal fluid flow in syringomyelia patients associated with Chiari I malformation using phase-contrast velocity-encoded-cine MRI and also to find out whether treatment outcomes may be predicted by these flow measurements. MATERIAL AND METHODS: Eighteen consecutive symptomatic patients with syringomyelia associated with Chiari 1 malformation were included. The PC VEC MRI was performed at the level of foramen magnum and syrinx cavity both preoperatively and 6 months postoperatively. Following surgery, the modified Asgari score was calculated, and the association between CSF flow pattern and clinical outcome was assessed. RESULTS: Evaluation of clinical symptoms at postoperative 6th month revealed improvement in 11 (61%) patients and stabilization in 5 (28%) patients whereas results were poor in 2 (11%) patients. Preoperative cine MRI flow studies showed a heterogeneous pattern at the foramen magnum level in all of the patients. Postoperative cine MR flow studies demonstrated the change from heterogeneous pattern to sinusoidal pattern in 11 patients and a decrease in heterogeneity in 7 patients. CONCLUSION: Our results indicate that CSF flow measurements using PC VEC MRI can give important information regarding the prognosis and follow-up of the patients with Chiari I malformation. (+info)
Hemifacial spasm in a patient with neurofibromatosis and Arnold-Chiari malformation: a unique case association.
BACKGROUND: The association of hemifacial spasm (HFS), Chiari type I malformation (CIM) and neurofibromatosis type 1 (NF1) has not been described yet. CASE REPORT: We report the case of a 31-year-old woman with NF1 who developed a right-sided HFS. On magnetic resonance imaging (MRI) a CIM was seen without syringomyelia. The patient has been successfully treated with botulinum toxin type A injections for 5 years without major side effects. CONCLUSION: Clinical features of HFS, CMI and NF1 are highlighted together with their possible relationship. Also, therapeutic strategies are also discussed. (+info)
Supratentorial abnormalities in the Chiari II malformation, I: the ventricular "point".
OBJECTIVE: The sonographic diagnosis of fetal myelomeningocele has improved dramatically over the past 20 years, mainly because the diagnostic focus has shifted from observation of the spinal abnormality to observation of cranial abnormalities. We describe an abnormality in the shape of the occipital horn that has received scant attention in the sonographic literature. The abnormality is a misshapen occipital horn that is "pointed" rather than rounded. This study analyzed the frequency of this observation and technical aspects that improve its visualization. METHODS: From a database of obstetric sonograms, we searched for all cases in which open fetal myelomeningocele was sonographically detected. The search covered the period from 1999 to 2007. We then retrospectively reviewed the fetal intracranial findings in each case, with special attention to the contour of the occipital horn of the lateral ventricle. RESULTS: A total of 89 fetuses were identified. The mean and median gestational ages were 22 weeks 4 days and 22 weeks 2 days, respectively. Of the 89 cases, 62 (70%) had an occipital horn with a pointed shape. This abnormality was better seen in cases judged to be well visualized and in cases in which digital video clips were available for review. The abnormality was more frequently seen in fetuses at less than 24 weeks' gestation and in fetuses without ventriculomegaly. Finally, it was seen as commonly among fetuses with mild posterior fossa deformations as in those with more severe distortions. CONCLUSIONS: The occipital point is a common supratentorial feature of the Chiari II malformation. It is seen more commonly in fetuses at less than 24 weeks and in fetuses with normal-sized ventricles. As well, it is seen as commonly among fetuses with mild posterior fossa deformations as in those with more severe distortions. Therefore, its usefulness is enhanced as an observation in the armamentarium of cranial findings for detection of fetal myelomeningocele. (+info)
White matter microstructural abnormalities in children with spina bifida myelomeningocele and hydrocephalus: a diffusion tensor tractography study of the association pathways.