Fourth ventricle roof angle as a measure of fourth ventricle bowing and a radiographic predictor of brainstem dysfunction in Chiari malformation type I

2021 ◽  
pp. 1-8
Author(s):  
Scott C. Seaman ◽  
Luyuan Li ◽  
Arnold H. Menezes ◽  
Brian J. Dlouhy
Keyword(s):  
Fourth Ventricle ◽  
Foramen Magnum ◽  
Clinical Severity ◽  
Type I ◽  
Healthy Controls ◽  
Tonsillar Herniation ◽  
Chiari Malformation Type I ◽  
Brainstem Dysfunction ◽  
Roof Angle ◽  
Tonsillar Descent

OBJECTIVE Chiari malformation type I (CM-I) is a congenital and developmental abnormality that results in tonsillar descent 5 mm below the foramen magnum. However, this cutoff value has poor specificity as a predictor of clinical severity. Therefore, the authors sought to identify a novel radiographic marker predictive of clinical severity to assist in the management of patients with CM-I. METHODS The authors retrospectively reviewed 102 symptomatic CM-I (sCM-I) patients and compared them to 60 age-matched normal healthy controls and 30 asymptomatic CM-I (aCM-I) patients. The authors used the fourth ventricle roof angle (FVRA) to identify fourth ventricle “bowing,” a configuration change suggestive of fourth ventricle outlet obstruction, and compared these results across all three cohorts. A receiver operating characteristic (ROC) curve was used to identify a predictive cutoff for brainstem dysfunction. Binary logistic regression was used to determine whether bowing of the fourth ventricle was more predictive of brainstem dysfunction than tonsillar descent, clival canal angle, or obex position in aCM-I and sCM-I patients. RESULTS The FVRA had excellent interrater reliability (intraclass correlation 0.930, 95% CI 0.905–0.949, Spearman r2 = 0.766, p < 0.0001). The FVRA was significantly greater in the sCM-I group than the aCM-I and healthy control groups (59.3° vs 41.8° vs 45.2°, p < 0.0001). No difference was observed between aCM-I patients and healthy controls (p = 0.347). ROC analysis indicated that an FVRA of 65° had a specificity of 93% and a sensitivity of 50%, with a positive predictive value of 76% for brainstem dysfunction. FVRA > 65° was more predictive of brainstem dysfunction (OR 5.058, 95% CI 1.845–13.865, p = 0.002) than tonsillar herniation > 10 mm (OR 2.564, 95% CI 1.050–6.258, p = 0.039), although increasing age was also associated with brainstem dysfunction (OR 1.045, 95% CI 1.011–1.080, p = 0.009). A clival canal angle < 140° (p = 0.793) and obex below the foramen magnum (p = 0.563) had no association with brainstem dysfunction. CONCLUSIONS The authors identified a novel radiographic measure, the FVRA, that can be used to assess fourth ventricular bowing in CM-I and is more predictive of brainstem dysfunction than tonsillar herniation. The FVRA is easy to measure, has excellent interrater variability, and can be a reliable universal radiographic measure. The FVRA will be useful in further describing CM-I radiographically and clinically by identifying patients more likely to be symptomatic as a result of brainstem dysfunction.

Complete posterior cranial vault distraction osteogenesis to correct Chiari malformation type I associated with craniosynostosis

2021 ◽  
pp. 1-7
Keyword(s):  
Foramen Magnum ◽  
Posterior Cranial Fossa ◽  
Type I ◽  
Intracranial Volume ◽  
Tonsillar Herniation ◽  
Chiari Malformation Type I ◽  
Cerebellar Tonsillar Herniation ◽  
Cranial Fossa ◽  
The Mean ◽  
Tonsillar Descent

OBJECTIVE Posterior vault distraction osteogenesis (PVDO) is an effective tool to increase intracranial volume and expand the posterior cranial fossa. During PVDO, the authors extended osteotomy posterior to the foramen magnum to fully expand the posterior cranial fossa. The aim of this study was to investigate the efficacy of complete PVDO in posterior fossa expansion and treatment of Chiari malformation type I (CM-I) in patients with craniosynostosis. METHODS Patients with craniosynostosis who had undergone complete PVDO between January 2012 and May 2020 were reviewed retrospectively. A coronal osteotomy extending to the foramen magnum was performed and the foramen magnum was decompressed by removing its posterior rim with a 1-mm Kerrison rongeur. Four distractor devices were placed and the vector of distraction was controlled from the posterior to the inferior-posterior direction, depending on the deformity. Changes in the intracranial volume, posterior cranial fossa area, and cerebellar tonsillar descent were measured after complete PVDO by using CT and MRI. RESULTS A total of 11 patients with craniosynostosis and concurrent CM-I were included in the study. The mean age was 34.6 ± 24.0 months (continuous variables are expressed as the mean ± SD throughout). One patient had sleep apnea, which was consistent with CM-I, and another patient had a headache, which was nonspecific. The intracranial volume increased from 1179.6 ± 180.2 cm3 to 1440.6 ± 251.5 cm3 (p = 0.003; 24.5% increase compared to the preoperative volume). The posterior skull base area increased from 44.9 ± 19.3 cm2 to 72.7 ± 18.1 cm2 (p = 0.004). Cerebellar tonsillar descent decreased in all 11 patients after complete PVDO (preoperative: 10.8 ± 3.7 mm, postoperative: 2.7 ± 3.0 mm; p = 0.003). Among the 11 patients, 5 showed complete resolution of cerebellar tonsillar herniation. CONCLUSIONS Complete PVDO can more efficiently expand the posterior cranial fossa, unlike conventional methods. Moreover, it helps to relieve cerebellar tonsillar herniation. Complete PVDO is a powerful tool to increase the intracranial and posterior fossa volumes in patients with craniosynostosis and concurrent CM-I.

scholarly journals Intradural pathology and pathophysiology associated with Chiari I malformation in children and adults with and without syringomyelia

2017 ◽  
Vol 20 (6) ◽  
pp. 526-541 ◽  
Author(s):  
Brian J. Dlouhy ◽  
Jeffrey D. Dawson ◽  
Arnold H. Menezes
Keyword(s):  
Logistic Regression ◽  
Posterior Fossa ◽  
Fourth Ventricle ◽  
Posterior Inferior Cerebellar Artery ◽  
Type I ◽  
Csf Flow ◽  
Multivariate Logistic Regression ◽  
Tonsillar Herniation ◽  
Chiari Malformation Type I ◽  
Flow Channels

OBJECTIVEThe pathophysiology underlying tonsillar herniation and CSF obstruction in Chiari malformation Type I (CM-I) is unclear, and the cause of CM-I–associated syringomyelia is not well understood. A better understanding of this pathophysiology is important for an improved treatment strategy. Therefore, the authors sought to identify, characterize, and examine the intradural pathology and CSF flow pathophysiology in the posterior fossa and at the level of the foramen magnum that occurs in the setting of CM-I. They determined the incidence of these intradural findings and assessed differences across age, with the degree of tonsillar herniation, and in the presence and absence of syringomyelia.METHODSA prospective database initiated in March 2003 recorded all intraoperative findings during surgical treatment of children and adults with CM-I with or without syringomyelia. A total of 389 surgeries for CM-I were performed in 379 patients between March 2003 and June 2016. A total of 109 surgeries were performed in 109 patients with CM-I (without osseoligamentous abnormalities) in whom both a posterior fossa extradural and intradural decompression with duraplasty was performed (first-time intradural procedures). Using a surgical microscope, intradural pathology and obstruction of CSF channels were identified and assessed. Student t-tests and Fisher’s exact tests compared groups in a series of univariate analyses, followed by multivariate logistic regression.RESULTSThe following intradural pathological entities were observed (prevalence noted in parentheses). These include those that did not obstruct CSF flow channels: opacified arachnoid (33.0%), thickened arachnoid (3.7%), ischemic and gliotic tonsils (40.4%), tonsillar cysts (0.9%), and inferior descent of the fourth ventricle and cervicomedullary junction (CMJ) (78.0%). The following intradural pathological entities were observed to obstruct CSF flow channels: medialized tonsils (100%), tonsil overlying and obstructing the foramen of Magendie (21.1%), intertonsillar and tonsil to CMJ arachnoid adhesions (85.3%), vermian posterior inferior cerebellar artery branches obstructing the foramen of Magendie (43.1%), and arachnoid veils or webs obstructing or occluding the foramen of Magendie (52.3%). Arachnoid veils varied in type and were observed in 59.5% of patients with CM-I who had syringomyelia, which was significantly greater than the 33.3% of patients with CM-I without syringomyelia who had an arachnoid veil (p = 0.018). The presence of CM-I with an arachnoid veil had 3.22 times the odds (p = 0.013, 95% CI 1.29–8.07, by multivariate logistic regression) of being associated with syringomyelia, adjusting for tonsillar herniation. The inferior descent of the fourth ventricle and CMJ occurred with a greater degree of tonsillar herniation (p < 0.001) and correlated with a cervicomedullary kink or buckle on preoperative MRI.CONCLUSIONSIntradural pathology associated with CM-I with or without syringomyelia exists in many forms, is more prevalent than previously recognized in patients of all ages, and may play a role in the pathophysiology of CM-I tonsillar herniation. Arachnoid veils appear to partially obstruct CSF flow, are significantly more prevalent in cases of CM-I with syringomyelia, and therefore may play a role in the pathophysiology of CM-I–associated syringomyelia.

Posterior fossa arachnoid cyst, tonsillar herniation, and syringomyelia in trichorhinophalangeal syndrome Type I

2008 ◽  
Vol 109 (4) ◽  
pp. 746-750 ◽  
Author(s):  
Juan F. Martínez-Lage ◽  
Antonio Ruiz-Espejo ◽  
Encarna Guillén-Navarro ◽  
María-José Almagro
Keyword(s):  
Posterior Fossa ◽  
Arachnoid Cyst ◽  
Endochondral Ossification ◽  
Spinal Pain ◽  
Type I ◽  
Syndrome Type ◽  
Tonsillar Herniation ◽  
Chiari Malformation Type I ◽  
Trichorhinophalangeal Syndrome ◽  
Tonsillar Descent

The authors report the case of a patient with Chiari malformation Type I (CM-I) and syringomyelia probably caused by a retrocerebellar arachnoid cyst. The patient's phenotype corresponded to trichorhinophalangeal syndrome Type I. The authors attributed the origin of both the retrocerebellar cyst and the abnormal posterior fossa to endochondral ossification anomalies that occur in this syndrome. The patient's spinal pain was most likely a result of the combination of CM-I and syringomyelia. To the best of the authors' knowledge, this is the first report on the association of CM-I and syringomyelia with a retrocerebellar arachnoid cyst occurring in a patient with trichorhinophalangeal syndrome Type I. The authors discuss the pathogenetic mechanisms involved in the production of tonsillar descent and syringomyelia in this patient, and review the current literature on related conditions that can result in this association.

Cervical spinal motion before and after surgery in patients with Chiari malformation Type I associated with syringomyelia

2007 ◽  
Vol 7 (5) ◽  
pp. 473-477 ◽  
Author(s):  
Atsushi Ono ◽  
Futoshi Suetsuna ◽  
Kazumasa Ueyama ◽  
Toru Yokoyama ◽  
Shuichi Aburakawa ◽  
...  
Keyword(s):  
Foramen Magnum ◽  
Type I ◽  
Foramen Magnum Decompression ◽  
Chiari Malformation Type I ◽  
Spinal Motion ◽  
Flexion Extension ◽  
Before And After ◽  
The Mean ◽  
The Relationship ◽  
Tonsillar Descent

Object There have been few reports about the cervical spinal motion in patients with Chiari malformation Type I (CM-I) associated with syringomyelia. To investigate this phenomenon, the relationship between the preoperative cervical range of motion (ROM) and the stage of cerebellar tonsillar descent as well as the cervical ROM before and after foramen magnum decompression (FMD) were evaluated. Methods Thirty patients who had CM-I associated with syringomyelia and who underwent FMD participated in the study. The ROM and lordosis angle of the cervical spine were measured on x-ray films. In addition, the relationship between preoperative degree of cerebellar tonsillar descent and the ROM between the levels of the occiput (Oc) and C2 was investigated. Results The mean flexion–extension ROM at Oc–C2 was 15.5° before and 14.1° after surgery, and the mean flexion–extension ROM of C2–7 was 55.1° before and 52.8° after surgery. The mean pre- and postoperative lordosis angles at C2–7 were 16.8 and 19.1°, respectively. There was no significant difference between the values measured before and after surgery. There was no correlation between the degree of cerebellar tonsillar descent and the ROM at Oc–C2. Conclusions Foramen magnum decompression is an excellent surgical technique that has no effect on the postoperative cervical ROM and cervical alignment.

scholarly journals Case Report: Acute obstructive hydrocephalus associated with infratentorial extra-axial fluid collection following foramen magnum decompression and durotomy for Chiari malformation type I

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 33 ◽  
Author(s):  
Sunil Munakomi ◽  
Binod Bhattarai ◽  
Pramod Chaudhary
Keyword(s):  
Chiari Malformation ◽  
Fourth Ventricle ◽  
Rare Complication ◽  
Obstructive Hydrocephalus ◽  
Fluid Collection ◽  
Foramen Magnum ◽  
Type I ◽  
Foramen Magnum Decompression ◽  
Chiari Malformation Type I ◽  
Definitive Role

Acute obstructive hydrocephalus due to infratentorial extra-axial fluid collection (EAFC) is an extremely rare complication of foramen magnum decompression (FMD) and durotomy for Chiari malformation type I. Presence of infratentorial  EAFC invariably causes obstruction at the level of the fourth ventricle or aqueduct of Silvius, thereby indicating its definitive role in hydrocephalus. Pathogenesis of EAFC is said to be a local arachnoid tear as a result of durotomy, as this complication is not described in FMD without durotomy. Controversy exists in management. Usually EAFC is said to resolve with conservative management; so hydrocephalus doesn’t require treatment. However, in this case EAFC was progressive and ventriculo-peritoneal shunting (VPS) was needed for managing progressive and symptomatic hydrocephalus.

Chiari malformation Type I and syrinx in children undergoing magnetic resonance imaging

2011 ◽  
Vol 8 (2) ◽  
pp. 205-213 ◽  
Author(s):  
Jennifer Strahle ◽  
Karin M. Muraszko ◽  
Joseph Kapurch ◽  
J. Rajiv Bapuraj ◽  
Hugh J. L. Garton ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Mr Imaging ◽  
Chiari Malformation ◽  
Foramen Magnum ◽  
Type I ◽  
Csf Flow ◽  
Tonsillar Herniation ◽  
Chiari Malformation Type I ◽  
Age Related ◽  
Imaging Characteristics

Object Chiari malformation Type I (CM-I) with an associated spinal syrinx is a common pediatric diagnosis. A better understanding of the relative age-related prevalence and MR imaging characteristics of these associated conditions may lead to improved treatment decisions. Methods The authors performed a retrospective review of 14,116 consecutive individuals 18 years of age or younger who had undergone brain or cervical spine MR imaging at the University of Michigan between November 1997 and August 2008. In the patients with CM-I, demographic, clinical, and radiographic information was recorded. Results Five hundred nine children (3.6%) with CM-I were identified. Among these patients, 23% also had a spinal cord syrinx, and 86% of the syringes were found in the cervical spine. The MR imaging prevalence of CM-I with a syrinx was 1.2% in girls and 0.5% in boys (p < 0.0001). The severity of impaired CSF flow at the foramen magnum was associated with the amount of tonsillar herniation (p < 0.0001) and conformation of the tonsils (p < 0.0001). Patients with CM-I were treated surgically in 35% of cases; these patients exhibited more severe tonsillar herniation (p < 0.0001) and impaired CSF flow (p < 0.0001) as compared with those who did not undergo surgery. On imaging, 32% of all the patients with CM-I were considered symptomatic by the treating physician. Patients were more likely to be considered symptomatic if they were female, had a syrinx, displayed abnormal tonsillar pulsations, or had a greater amount of tonsillar herniation. Conclusions In this study the authors describe the age-related prevalence and MR imaging characteristics of CM-I and its association with a syrinx and other abnormalities in a large group of children who underwent MR imaging for any indication. Syringes are more common in older children, in girls, and in patients with a greater degree of tonsillar descent and CSF flow impairment.

Soft tissue density within the foramen magnum, a predictor for surgical intervention in pediatric patients with Chiari malformation type I

2020 ◽  
Vol 26 (6) ◽  
pp. 671-675
Author(s):  
William Fuell ◽  
Reem Elwy ◽  
Thomas Harkey ◽  
Matthew Carey ◽  
Gregory W. Albert
Keyword(s):  
Soft Tissue ◽  
Pediatric Patients ◽  
Surgical Intervention ◽  
Foramen Magnum ◽  
Type I ◽  
Soft Tissue Density ◽  
Tonsillar Herniation ◽  
Chiari Malformation Type I ◽  
Tissue Density ◽  
Cerebellar Tonsils

OBJECTIVEChiari malformation type I (CMI) is diagnosed as herniation of the cerebellar tonsils by at least 5 mm below the foramen magnum. However, the degree of tonsillar herniation is a poor predictor of the need for decompression surgery. Exploration for an alternative morphological predictor for surgical intervention could provide greater insight into the development of an appropriate treatment plan for these patients. To investigate this issue, the authors calculated the soft tissue density within the foramen magnum as a measure of impaction of the cerebellar tonsils. Soft tissue density within the foramen magnum and degree of tonsillar herniation were then assessed for their correlation with the need for surgical intervention.METHODSThe authors conducted a retrospective, longitudinal chart review of pediatric patients with CMI. Those who had undergone surgical intervention were considered symptomatic and those who had been treated conservatively, as asymptomatic. Soft tissue density was found by dividing the soft tissue occupancy of the foramen magnum (brainstem and cerebellar tonsils) by the total area of the bony foramen magnum. The predictive value of these two measurements for the need of surgery was determined.RESULTSOf the 465 patients seen for CMI at the authors’ institution between July 1, 2011, and May 31, 2017, 80 underwent surgical intervention and 385 were asymptomatic. The average tissue density was significantly greater in the surgical group than in the asymptomatic group (83.3% and 78.6%, respectively, p < 0.0001). The average tonsillar descent for surgical patients was 10.8 mm compared to 9.8 mm for asymptomatic patients (p = 0.140). The point-biserial correlation coefficient was assessed, and soft tissue density was found to positively correlate with the need for surgical intervention (rpb = 0.199, p = 0.0001), whereas tonsillar herniation did not correlate with the need for surgery (rpb = 0.083, p = 0.115). Additionally, the degree of tonsillar herniation did not correlate with soft tissue density (r = 0.09), indicating that soft tissue density is an independent morphological parameter.CONCLUSIONSThe study findings suggest that the need for surgical intervention in CMI patients is positively correlated with increasing soft tissue density within the foramen magnum, whereas the degree of tonsillar herniation did not show a correlation with the need for surgical intervention. Additionally, soft tissue density is a factor independent of the degree of tonsillar herniation. Further investigation of tissue density within the foramen magnum is needed in the hope of discovering a clinically applicable parameter that would indicate a need for surgical intervention in patients with CMI.

Prognostic significance of C1–C2 facet malalignment after surgical decompression in adult Chiari malformation type I: a pilot study based on the Chicago Chiari Outcome Scale

2020 ◽  
pp. 1-7
Author(s):  
Michael Lumintang Loe ◽  
Tito Vivas-Buitrago ◽  
Ricardo A. Domingo ◽  
Johan Heemskerk ◽  
Shashwat Tripathi ◽  
...  
Keyword(s):  
Pilot Study ◽  
Chiari Malformation ◽  
Prognostic Significance ◽  
Foramen Magnum ◽  
Bivariate Analysis ◽  
Type I ◽  
Foramen Magnum Decompression ◽  
Swallowing Function ◽  
Chiari Malformation Type I

OBJECTIVEThe authors assessed the prognostic significance of various clinical and radiographic characteristics, including C1–C2 facet malalignment, in terms of surgical outcomes after foramen magnum decompression of adult Chiari malformation type I.METHODSThe electronic medical records of 273 symptomatic patients with Chiari malformation type I who were treated with foramen magnum decompression, C1 laminectomy, and duraplasty at Mayo Clinic were retrospectively reviewed. Preoperative and postoperative Neurological Scoring System scores were compared using the Friedman test. Bivariate analysis was conducted to identify the preoperative variables that correlated with the patient Chicago Chiari Outcome Scale (CCOS) scores. Multiple linear regression analysis was subsequently performed using the variables with p < 0.05 on the bivariate analysis to check for independent associations with the outcome measures. Statistical software SPSS version 25.0 was used for the data analysis. Significance was defined as p < 0.05 for all analyses.RESULTSFifty-two adult patients with preoperative clinical and radiological data and a minimum follow-up of 12 months were included. Motor deficits, syrinx, and C1–C2 facet malalignment were found to have significant negative associations with the CCOS score at the 1- to 3-month follow-up (p < 0.05), while at the 9- to 12-month follow-up only swallowing function and C1–C2 facet malalignment were significantly associated with the CCOS score (p < 0.05). Multivariate analysis showed that syrinx presence and C1–C2 facet malalignment were independently associated with the CCOS score at the 1- to 3-month follow-up. Swallowing function and C1–C2 facet malalignment were found to be independently associated with the CCOS score at the 9- to 12-month follow-up.CONCLUSIONSThe observed results in this pilot study suggest a significant negative correlation between C1–C2 facet malalignment and clinical outcomes evaluated by the CCOS score at 1–3 months and 9–12 months postoperatively. Prospective studies are needed to further validate the prognostic value of C1–C2 facet malalignment and the potential role of atlantoaxial fixation as part of the treatment.

Regional Brain Tissue Displacement and Strain is Elevated in Subjects with Chiari Malformation Type I Compared to Healthy Controls: A Study Using DENSE MRI

2021 ◽  
Author(s):  
Blaise Simplice Talla Nwotchouang ◽  
Maggie S. Eppelheimer ◽  
Soroush Heidari Pahlavian ◽  
Jack W. Barrow ◽  
Daniel L. Barrow ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Chiari Malformation ◽  
Type I ◽  
Healthy Controls ◽  
Chiari Malformation Type I ◽  
Regional Brain

scholarly journals Standard and cardiac-gated phase-contrast magnetic resonance imaging in the clinical course of patients with Chiari malformation Type I

2011 ◽  
Vol 31 (3) ◽  
pp. E5 ◽  
Author(s):  
Uwe Max Mauer ◽  
Andreas Gottschalk ◽  
Carolin Mueller ◽  
Linda Weselek ◽  
Ulrich Kunz ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Chiari Malformation ◽  
Phase Contrast ◽  
Foramen Magnum ◽  
Central Canal ◽  
Type I ◽  
Csf Flow ◽  
Chiari Malformation Type I ◽  
Cerebrospinal Fluid Flow ◽  
Contrast Magnetic Resonance

Object The causal treatment of Chiari malformation Type I (CM-I) consists of removing the obstruction of CSF flow at the level of the foramen magnum. Cerebrospinal fluid flow can be visualized using dynamic phase-contrast MR imaging. Because there is only a paucity of studies evaluating CSF dynamics in the region of the spinal canal on the basis of preoperative and postoperative measurements, the authors investigated the clinical usefulness of cardiacgated phase-contrast MR imaging in patients with CM-I. Methods Ninety patients with CM-I underwent preoperative MR imaging of CSF pulsation. Syringomyelia was present in 59 patients and absent in 31 patients. Phase-contrast MR imaging of the entire CNS was used to investigate 22 patients with CM-I before surgery and after a mean postoperative period of 12 months (median 12 months, range 3–33 months). In addition to the dynamic studies, absolute flow velocities, the extension of the syrinx, and tonsillar descent were also measured. Results The changes in pulsation were highly significant in the region of the (enlarged) cistern (p = 0.0005). Maximum and minimum velocities (the pulsation amplitude) increased considerably in the region where the syrinx was largest in diameter. The changes of pulsation in these patients were significant in the subarachnoid space in all spinal segments but not in the syrinx itself and in the central canal. Conclusions The demonstration of CSF flow pulsation can contribute to assessments of surgical outcomes. The results presented here, however, raise doubts about current theories on the pathogenesis of syringomyelia.

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