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.

Inclination of the odontoid process in the pediatric Chiari I malformation

2003 ◽  
Vol 98 (1) ◽  
pp. 43-49 ◽  
Author(s):  
R. Shane Tubbs ◽  
John C. Wellons ◽  
Jeffrey P. Blount ◽  
Paul A. Grabb ◽  
W. Jerry Oakes
Keyword(s):  
Odontoid Process ◽  
Postoperative Outcome ◽  
Craniocervical Junction ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Magnetic Resonance Images ◽  
Posterior Aspect ◽  
Content Type ◽  
Chiari I ◽  
Fine Print

Object. The quantitative analysis of odontoid process angulation has had scant attention in the Chiari I malformation population. In this study the authors sought to elucidate the correlation between posterior angulation of the odontoid process and patients with Chiari I malformation. Methods. Magnetic resonance images of the craniocervical junction obtained in 100 children with Chiari I malformation and in 50 children with normal intracranial anatomy (controls) were analyzed. Specific attention was focused on measuring the degree of angulation of the odontoid process and assigning a score to the various degrees. Postoperative outcome following posterior cranial fossa decompression was then correlated to grades of angulation. Other measurements included midsagittal lengths of the foramen magnum and basiocciput, the authors' institutions' previously documented pB—C2 line (a line drawn perpendicular to one drawn between the basion and the posterior aspect of the C-2 body), level of the obex from a midpoint of the McRae line, and the extent of tonsillar herniation. Higher grades of odontoid angulation (retroflexion) were found to be more frequently associated with syringomyelia and particularly holocord syringes. Higher grades of angulation were more common in female patients and were often found to have obices that were caudally displaced greater than three standard deviations below normal. Conclusions. These results not only confirm prior reports of an increased incidence of a retroflexed odontoid process in Chiari I malformation but quantitatively define grades of inclination. Grades of angulation were not found to correlate with postoperative outcome. It is the authors' hopes that these data add to our current limited understanding of the mechanisms involved in hindbrain herniation.

The first description of Chiari I malformation with intuitive correlation between tonsillar ectopia and syringomyelia

2011 ◽  
Vol 7 (3) ◽  
pp. 257-260 ◽  
Author(s):  
Martin M. Mortazavi ◽  
R. Shane Tubbs ◽  
Maja Andrea Brockerhoff ◽  
Marios Loukas ◽  
W. Jerry Oakes
Keyword(s):  
Craniocervical Junction ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Current Understanding ◽  
Tonsillar Ectopia ◽  
Cause And Effect ◽  
Hindbrain Herniation ◽  
Chiari I

Few are familiar with the neurological contributions of the German pathologist Theodor Langhans. Even fewer are aware of his significant and early contributions to the study of what is now known as the Chiari I malformation. In at least 4 cases, Langhans described the association between tonsillar ectopia and syringomyelia. Moreover, this early pioneer speculated that there was a cause and effect with hindbrain herniation resulting in improper flow at the craniocervical junction and consequent development of syringomyelia. These cases were reported prior to Hans Chiari's descriptions, and Langhans' theory of impeded foramen magnum flow as a cause of syringomyelia was novel and preceded the current understanding of this mechanism by almost a century. The authors discuss the life of Langhans and translate excerpts from his 1881 work regarding tonsillar ectopia and syringomyelia.

scholarly journals Evaluating the relationship of the pB–C2 line to clinical outcomes in a 15-year single-center cohort of pediatric Chiari I malformation

2015 ◽  
Vol 15 (2) ◽  
pp. 178-188 ◽  
Author(s):  
Travis R. Ladner ◽  
Michael C. Dewan ◽  
Matthew A. Day ◽  
Chevis N. Shannon ◽  
Luke Tomycz ◽  
...  
Keyword(s):  
Line Length ◽  
Chiari I Malformation ◽  
Categorical Variables ◽  
Posterior Fossa Decompression ◽  
Chiari I ◽  
The Mean ◽  
Canal Encroachment ◽  
The Relationship ◽  
Ventral Canal ◽  
Age And Sex

OBJECT The clinical significance of radiological measurements of the craniocervical junction in pediatric Chiari I malformation (CM-I) is yet to be fully established across the field. The authors examined their institutional experience with the pB–C2 line (drawn perpendicular to a line drawn between the basion and the posterior aspect of the C-2 vertebral body, at the most posterior extent of the odontoid process at the dural interface). The pB–C2 line is a measure of ventral canal encroachment, and its relationship with symptomatology and syringomyelia in pediatric CM-I was assessed. METHODS The authors performed a retrospective review of 119 patients at the Monroe Carell Jr. Children's Hospital at Vanderbilt University who underwent posterior fossa decompression with duraplasty, 78 of whom had imaging for review. A neuroradiologist retrospectively evaluated preoperative and postoperative MRI examinations performed in these 78 patients, measuring the pB–C2 line length and documenting syringomyelia. The pB–C2 line length was divided into Grade 0 (< 3 mm) and Grade I (≥ 3 mm). Statistical analysis was performed using the t-test for continuous variables and Fisher's exact test analysis for categorical variables. Multivariate logistic and linear regression analyses were performed to assess the relationship between pB–C2 line grade and clinical variables found significant on univariate analysis, controlling for age and sex. RESULTS The mean patient age was 8.5 years, and the mean follow-up duration was 2.4 years. The mean pB–C2 line length was 3.5 mm (SD 2 mm), ranging from 0 to 10 mm. Overall, 65.4% of patients had a Grade I pB–C2 line. Patients with Grade I pB–C2 lines were 51% more likely to have a syrinx than those with Grade 0 pB–C2 lines (RR 1.513 [95% CI 1.024–2.90], p = 0.021) and, when present, had greater syrinx reduction (3.6 mm vs 0.2 mm, p = 0.002). Although there was no preoperative difference in headache incidence, postoperatively patients with Grade I pB–C2 lines were 69% more likely to have headache reduction than those with Grade 0 pB–C2 lines (RR 1.686 [95% CI 1.035–2.747], p = 0.009). After controlling for age and sex, pB–C2 line grade remained an independent correlate of headache improvement and syrinx reduction. CONCLUSIONS Ventral canal encroachment may explain the symptomatology of select patients with CM-I. The clinical findings presented suggest that patients with Grade I pB–C lines2, with increased ventral canal obstruction, may experience a higher likelihood of syrinx reduction and headache resolution from decompressive surgery with duraplasty than those with Grade 0 pB–C2 lines.

scholarly journals Chiari I malformation with Klippel-Trenaunay syndrome: case report and review of the literature

2021 ◽  
Author(s):  
Isabel A. Snee ◽  
Catherine A. Mazzola ◽  
Tatiana Sikorskyj
Keyword(s):  
Facial Asymmetry ◽  
Clinical History ◽  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Posterior Fossa Decompression ◽  
Leg Length ◽  
Upper And Lower Extremities ◽  
Chiari I ◽  
Klippel Trenaunay Syndrome ◽  
Cerebellar Tonsils

AbstractWe present a rare case of an 8-year-old male with Klippel-Trenaunay syndrome (KTS) and a Chiari I malformation (CIM). Magnetic resonance imaging (MRI) to investigate facial asymmetry and speech delay at age two revealed CIM with cerebellar tonsils 1.3 cm below the foramen magnum without syringomyelia. The patient underwent a craniectomy and posterior fossa decompression with C1 laminectomy. While gene sequencing determined the patient was negative for the PIK3CA gene mutation, the patient’s clinical history strongly suggests KTS. He has hemihypertrophy, leg length discrepancy, hemangiomas and pigmentary mosaicism along the upper and lower extremities, heart murmur, chronic low heart rate, recurrent hip pain, and mild scoliosis. Neurodevelopmental concerns include difficulty reading, attention deficit hyperactivity disorder (ADHD), anxiety, and difficulty running and going downstairs. His most recent MRI shows good decompression at the cervicomedullary junction, global cerebrospinal fluid (CSF) flow, and less peg-like cerebellar tonsils. Also noted were two intravertebral hemangiomas at T5 and T6. While the patient’s speech has improved, there is still difficulty with the expressive language. He still has mild delays, runs slowly, and does not alternate feet when climbing stairs. The patient is being followed by multiple specialists including neurology, hematology-oncology, genetics, orthopedic surgery, and developmental pediatrics.

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.

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 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 Re-evaluation of foramen magnum decompression with dura left open for Chiari I malformation

2017 ◽  
Vol 10 ◽  
pp. 150-154 ◽  
Author(s):  
Tetsuryu Mitsuyama ◽  
Yasuo Aihara ◽  
Takaomi Taira ◽  
Seiichiro Eguchi ◽  
Kentaro Chiba ◽  
...  
Keyword(s):  
Foramen Magnum ◽  
Chiari I Malformation ◽  
Foramen Magnum Decompression ◽  
Chiari I
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