Osteopetrosis with Chiari I malformation: presentation and surgical management

2011 ◽  
Vol 7 (4) ◽  
pp. 369-374 ◽  
Author(s):  
Brian J. Dlouhy ◽  
Arnold H. Menezes
Keyword(s):  
Mr Imaging ◽  
Posterior Fossa ◽  
Autosomal Dominant ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Posterior Fossa Decompression ◽  
Imaging Data ◽  
Inherited Disorders ◽  
Chiari I ◽  
Autosomal Dominant Osteopetrosis

Osteopetrosis is a heterogeneous group of rare, inherited disorders of the skeleton that results in neurological manifestations due to restriction of growth of cranial foramina and calvarial thickening. A 25-year-old woman with a history of autosomal dominant osteopetrosis presented to the authors' institution with headache worsened by exertion and radiating from the occipital region forward with episodes of choking/coughing when eating and a loss of gag reflex on physical examination. On MR imaging, she was found to have severe posterior fossa calvarial thickening resulting in a small posterior fossa and tonsillar ectopia of 9 mm and compression and deformation of the brainstem. She underwent posterior fossa craniectomy, foramen magnum decompression, and partial C-1 laminectomy with external durotomy. The patient did well postoperatively with resolution of symptoms. This case describes a new neurological manifestation of autosomal dominant osteopetrosis. To the authors' knowledge, this report represents the first described case of extreme posterior fossa calvarial thickening from autosomal dominant osteopetrosis with associated Chiari I malformation (CM-I) requiring posterior fossa decompression and extradural decompression. Given previously published MR imaging data that demonstrate the association of osteopetrosis and CM may be more common than in this case alone, the authors discuss the need for further investigation of the incidence of CM-I in patients with autosomal dominant osteopetrosis. Additionally, they review osteopetrosis and other diagnoses of calvarial hyperostosis presenting as CM-I.

scholarly journals Changes in cerebrospinal fluid flow assessed using intraoperative MRI during posterior fossa decompression for Chiari malformation

2015 ◽  
Vol 122 (5) ◽  
pp. 1068-1075 ◽  
Author(s):  
Aaron E. Bond ◽  
John A. Jane ◽  
Kenneth C. Liu ◽  
Edward H. Oldfield
Keyword(s):  
Posterior Fossa ◽  
Intraoperative Imaging ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Intraoperative Mri ◽  
Cine Mri ◽  
Posterior Fossa Decompression ◽  
Csf Flow ◽  
Chiari I ◽  
Adequate Decompression

OBJECT The authors completed a prospective, institutional review board–approved study using intraoperative MRI (iMRI) in patients undergoing posterior fossa decompression (PFD) for Chiari I malformation. The purpose of the study was to examine the utility of iMRI in determining when an adequate decompression had been performed. METHODS Patients with symptomatic Chiari I malformations with imaging findings of obstruction of the CSF space at the foramen magnum, with or without syringomyelia, were considered candidates for surgery. All patients underwent complete T1, T2, and cine MRI studies in the supine position preoperatively as a baseline. After the patient was placed prone with the neck flexed in position for surgery, iMRI was performed. The patient then underwent a bone decompression of the foramen magnum and arch of C-1, and the MRI was repeated. If obstruction was still present, then in a stepwise fashion the patient underwent dural splitting, duraplasty, and coagulation of the tonsils, with an iMRI study performed after each step guiding the decision to proceed further. RESULTS Eighteen patients underwent PFD for Chiari I malformations between November 2011 and February 2013; 15 prone preincision iMRIs were performed. Fourteen of these patients (93%) demonstrated significant improvement of CSF flow through the foramen magnum dorsal to the tonsils with positioning only. This improvement was so notable that changes in CSF flow as a result of the bone decompression were difficult to discern. CONCLUSIONS The authors observed significant CSF flow changes when simply positioning the patient for surgery. These results put into question intraoperative flow assessments that suggest adequate decompression by PFD, whether by iMRI or intraoperative ultrasound. The use of intraoperative imaging during PFD for Chiari I malformation, whether by ultrasound or iMRI, is limited by CSF flow dynamics across the foramen magnum that change significantly when the patient is positioned for surgery.

scholarly journals Obex position is associated with syringomyelia and use of posterior fossa decompression among patients with Chiari I malformation

2020 ◽  
Vol 26 (1) ◽  
pp. 45-52
Author(s):  
Gabe Haller ◽  
Brooke Sadler ◽  
Timothy Kuensting ◽  
Nivan Lakshman ◽  
Jacob K. Greenberg ◽  
...  
Keyword(s):  
Posterior Fossa ◽  
Area Under The Curve ◽  
Retrospective Chart Review ◽  
Severity Index ◽  
Basilar Invagination ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Posterior Fossa Decompression ◽  
Radiological Measurements ◽  
Chiari I

OBJECTIVEChiari I malformation (CM-I) has traditionally been defined by measuring the position of the cerebellar tonsils relative to the foramen magnum. The relationships of tonsillar position to clinical presentation, syringomyelia, scoliosis, and the use of posterior fossa decompression (PFD) surgery have been studied extensively and yielded inconsistent results. Obex position has been proposed as a useful adjunctive descriptor for CM-I and may be associated with clinical disease severity.METHODSA retrospective chart review was performed of 442 CM-I patients with MRI who presented for clinical evaluation between 2003 and 2018. Clinical and radiological variables were measured for all patients, including presence/location of headaches, Chiari Severity Index (CSI) grade, tonsil position, obex position, clival canal angle, pB-C2 distance, occipitalization of the atlas, basilar invagination, syringomyelia, syrinx diameter, scoliosis, and use of PFD. Radiological measurements were then used to predict clinical characteristics using regression and survival analyses, with performing PFD, the presence of a syrinx, and scoliosis as outcome variables.RESULTSAmong the radiological measurements, tonsil position, obex position, and syringomyelia were each independently associated with use of PFD. Together, obex position, tonsil position, and syringomyelia (area under the curve [AUC] 89%) or obex position and tonsil position (AUC 85.4%) were more strongly associated with use of PFD than tonsil position alone (AUC 76%) (Pdiff = 3.4 × 10−6 and 6 × 10−4, respectively) but were only slightly more associated than obex position alone (AUC 82%) (Pdiff = 0.01 and 0.18, respectively). Additionally, obex position was significantly associated with occipital headaches, CSI grade, syringomyelia, and scoliosis, independent of tonsil position. Tonsil position was associated with each of these traits when analyzed alone but did not remain significantly associated with use of PFD when included in multivariate analyses with obex position.CONCLUSIONSCompared with tonsil position alone, obex position is more strongly associated with symptomatic CM-I, as measured by presence of a syrinx, scoliosis, or use of PFD surgery. These results support the role of obex position as a useful radiological measurement to inform the evaluation and potentially the management of CM-I.

Chiari Type I Malformation Presenting as Hemifacial Spasm: Case Report

Neurosurgery ◽  
2005 ◽  
Vol 57 (2) ◽  
pp. E371-E371 ◽  
Author(s):  
Mustafa Efkan Colpan ◽  
Zeki Sekerci
Keyword(s):  
Facial Nerve ◽  
Posterior Fossa ◽  
Hemifacial Spasm ◽  
Chiari I Malformation ◽  
Posterior Fossa Decompression ◽  
Type I ◽  
Chiari Type I Malformation ◽  
Downward Displacement ◽  
Facial Spasm ◽  
Chiari I

ABSTRACT OBJECTIVE AND IMPORTANCE: We report on a patient with a Chiari I malformation presenting with right hemifacial spasm. Clinicians should consider the downward displacement of the hindbrain as a rare cause of hemifacial spasm in Chiari I malformation. CLINICAL PRESENTATION: An 18-year-old man was admitted with right hemifacial spasm. The results of the neurological examination were normal except for the facial spasm. Magnetic resonance imaging demonstrated a Chiari I malformation without syringomyelia. After surgery, the hemifacial spasm completely resolved. INTERVENTION: Posterior fossa decompression, C1 laminectomy, and duraplasty were performed. CONCLUSION: The hemifacial spasm could be attributed to compression and/or traction of the facial nerve because of downward displacement of the hindbrain in Chiari I malformation. Compression and/or traction might create irritation of the facial nerve that causes hemifacial spasm. Resolution of the hemifacial spasm after posterior fossa decompression could explain the facial nerve irritation in Chiari I malformation. Clinicians should consider Chiari malformation as a cause of hemifacial spasm and posterior fossa decompression as a potential treatment.

scholarly journals Posterior odontoid process angulation in pediatric Chiari I malformation: an MRI morphometric external validation study

2015 ◽  
Vol 16 (2) ◽  
pp. 138-145 ◽  
Author(s):  
Travis R. Ladner ◽  
Michael C. Dewan ◽  
Matthew A. Day ◽  
Chevis N. Shannon ◽  
Luke Tomycz ◽  
...  
Keyword(s):  
External Validation ◽  
Age Groups ◽  
Odontoid Process ◽  
Line Length ◽  
Craniocervical Junction ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Posterior Fossa Decompression ◽  
Tonsillar Ectopia ◽  
Chiari I

OBJECT Osseous anomalies of the craniocervical junction are hypothesized to precipitate the hindbrain herniation observed in Chiari I malformation (CM-I). Previous work by Tubbs et al. showed that posterior angulation of the odontoid process is more prevalent in children with CM-I than in healthy controls. The present study is an external validation of that report. The goals of our study were 3-fold: 1) to externally validate the results of Tubbs et al. in a different patient population; 2) to compare how morphometric parameters vary with age, sex, and symptomatology; and 3) to develop a correlative model for tonsillar ectopia in CM-I based on these measurements. METHODS The authors performed a retrospective review of 119 patients who underwent posterior fossa decompression with duraplasty at the Monroe Carell Jr. Children’s Hospital at Vanderbilt University; 78 of these patients had imaging available for review. Demographic and clinical variables were collected. A neuroradiologist retrospectively evaluated preoperative MRI examinations in these 78 patients and recorded the following measurements: McRae line length; obex displacement length; odontoid process parameters (height, angle of retroflexion, and angle of retroversion); perpendicular distance to the basion-C2 line (pB–C2 line); length of cerebellar tonsillar ectopia; caudal extent of the cerebellar tonsils; and presence, location, and size of syringomyelia. Odontoid retroflexion grade was classified as Grade 0, > 90°; Grade I,85°–89°; Grade II, 80°–84°; and Grade III, < 80°. Age groups were defined as 0–6 years, 7–12 years, and 13–17 years at the time of surgery. Univariate and multivariate linear regression analyses, Kruskal-Wallis 1-way ANOVA, and Fisher’s exact test were performed to assess the relationship between age, sex, and symptomatology with these craniometric variables. RESULTS The prevalence of posterior odontoid angulation was 81%, which is almost identical to that in the previous report (84%). With increasing age, the odontoid height (p < 0.001) and pB–C2 length (p < 0.001) increased, while the odontoid process became more posteriorly inclined (p = 0.010). The pB–C2 line was significantly longer in girls (p = 0.006). These measurements did not significantly correlate with symptomatology. Length of tonsillar ectopia in pediatric CM-I correlated with an enlarged foramen magnum (p = 0.023), increasing obex displacement (p = 0.020), and increasing odontoid retroflexion (p < 0.001). CONCLUSIONS Anomalous bony development of the craniocervical junction is a consistent feature of CM-I in children. The authors found that the population at their center was characterized by posterior angulation of the odontoid process in 81% of cases, similar to findings by Tubbs et al. (84%). The odontoid process appeared to lengthen and become more posteriorly inclined with age. Increased tonsillar ectopia was associated with more posterior odontoid angulation, a widened foramen magnum, and an inferiorly displaced obex.

Elucidating the pathophysiology of syringomyelia

1999 ◽  
Vol 91 (4) ◽  
pp. 553-562 ◽  
Author(s):  
John D. Heiss ◽  
Nicholas Patronas ◽  
Hetty L. DeVroom ◽  
Thomas Shawker ◽  
Robert Ennis ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Subarachnoid Space ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Content Type ◽  
Cine Mr ◽  
Spinal Subarachnoid Space ◽  
Chiari I ◽  
Cerebellar Tonsils ◽  
Fine Print

Object. Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy.Methods. The authors prospectively studied 20 adult patients with both Chiari I malformation and symptomatic syringomyelia. Testing before surgery included the following: clinical examination; evaluation of anatomy by using T1-weighted magnetic resonance (MR) imaging; evaluation of the syrinx and cerebrospinal fluid (CSF) velocity and flow by using phase-contrast cine MR imaging; and evaluation of lumbar and cervical subarachnoid pressure at rest, during the Valsalva maneuver, during jugular compression, and following removal of CSF (CSF compliance measurement). During surgery, cardiac-gated ultrasonography and pressure measurements were obtained from the intracranial, cervical subarachnoid, and lumbar intrathecal spaces and syrinx. Six months after surgery, clinical examinations, MR imaging studies, and CSF pressure recordings were repeated. Clinical examinations and MR imaging studies were repeated annually. For comparison, 18 healthy volunteers underwent T1-weighted MR imaging, cine MR imaging, and cervical and lumbar subarachnoid pressure testing.Compared with healthy volunteers, before surgery, the patients had decreased anteroposterior diameters of the ventral and dorsal CSF spaces at the foramen magnum. In patients, CSF velocity at the foramen magnum was increased, but CSF flow was reduced. Transmission of intracranial pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was partially obstructed. Spinal CSF compliance was reduced, whereas cervical subarachnoid pressure and pulse pressure were increased. Syrinx fluid flowed inferiorly during systole and superiorly during diastole on cine MR imaging. At surgery, the cerebellar tonsils abruptly descended during systole and ascended during diastole, and the upper pole of the syrinx contracted in a manner synchronous with tonsillar descent and with the peak systolic cervical subarachnoid pressure wave. Following surgery, the diameter of the CSF passages at the foramen magnum increased compared with preoperative values, and the maximum flow rate of CSF across the foramen magnum during systole increased. Transmission of pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was normal and cervical subarachnoid mean pressure and pulse pressure decreased to normal. The maximum syrinx diameter decreased on MR imaging in all patients. Cine MR imaging documented reduced velocity and flow of the syrinx fluid. Clinical symptoms and signs improved or remained stable in all patients, and the tonsils resumed a normal shape.Conclusions. The progression of syringomyelia associated with Chiari I malformation is produced by the action of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. This creates enlarged cervical subarachnoid pressure waves that compress the spinal cord from without, not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to syrinx progression. The disappearance of the abnormal shape and position of the tonsils after simple decompressive extraarachnoidal surgery suggests that the Chiari I malformation of the cerebellar tonsils is acquired, not congenital. Surgery limited to suboccipital craniectomy, C-1 laminectomy, and duraplasty eliminates this mechanism and eliminates syringomyelia and its progression without the risk of more invasive procedures.

scholarly journals Is Chiari I Malformation Associated With Fibromyalgia?

Neurosurgery ◽  
2011 ◽  
Vol 68 (2) ◽  
pp. 443-449 ◽  
Author(s):  
Nathaniel F. Watson ◽  
Dedra Buchwald ◽  
Jack Goldberg ◽  
Kenneth R. Maravilla ◽  
Carolyn Noonan ◽  
...  
Keyword(s):  
Posterior Fossa ◽  
Sleep Disturbances ◽  
Cervical Spinal Cord ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Upper Cervical Spine ◽  
Fisher Exact Test ◽  
Contrast Imaging ◽  
Control Subjects ◽  
Chiari I

Abstract BACKGROUND: The symptoms of Chiari I Malformation (CIM) and fibromyalgia (FM) overlap. Some FM patients have been surgically treated for presumed CIM-type pathology. OBJECTIVE: To determine whether CIM is more common among FM patients than pain- and fatigue-free controls. METHODS: One hundred seventy-six participants with FM and 67 pain- and fatigue-free control subjects underwent magnetic resonance imaging of the brain and upper cervical spine. Posterior fossa cerebrospinal fluid flow was assessed with cardiac gated cine phase-contrast imaging at the craniocervical region. CIM was defined as inferior extension of cerebellar tonsils ≥ 5 mm below the basion-opisthion line of the foramen magnum or tonsillar position 3 to 5 mm below the basion-opisthion line plus abnormalities of CSF flow, posterior fossa volume, or hindbrain or cervical spinal cord movement. Visual analog scales, questionnaires, and interviews were used to collect data on sleep quality, fatigue, pain, and headache. We used regression techniques to examine the association of outcome measures with disease status and the Fisher exact test to compare the CIM prevalence in the 2 groups. RESULTS: The FM group was older (mean age, 50 vs 40 years) and more likely to be white (89% vs 73%) and female (93% vs 54%; P &lt; .01). Mean tonsillar position and the prevalence of CIM (2.8% vs 4.5%; P = .69) were similar in the FM and control groups. FM patients experienced more headaches, pain, fatigue, and sleep disturbances than control subjects (P &lt; .01). CONCLUSION: Most patients with FM do not have CIM pathology. Future studies should focus on dynamic neuroimaging of craniocervical neuroanatomy in patients with FM.

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