Dataset Information

Exploring the Pathogenesis of Atlanto-Occipital Instability in Chiari Malformation With Type II Basilar Invagination: A Systematic Morphological Study.

ABSTRACT:

Background

Our previous study suggested that atlanto-occipital instability (AOI) is common in patients with type II basilar invagination (II-BI).

Objective

To further understand the pathogenesis of AOI in Chiari malformations (CM) and CM + II-BI through systematic measurements of the bone structure surrounding the craniocervical junction.

Methods

Computed tomography data from 185 adults (80 controls, 63 CM, and 42 CM + II-BI) were collected, and geometric models were established for parameter measurement. Canonical correlation analysis was used to evaluate the morphological and positional relationships of the atlanto-occipital joint (AOJ).

Results

Among the 3 groups, the length and height of the condyle and superior portion of the lateral masses of the atlas (C1-LM) were smallest in CM + II-BI cases; the AOJ had the shallowest depth and the lowest curvature in the same group. AOJs were divided into 3 morphological types: type I, the typical ball-and-socket joint, mainly in the control group (100%); type II, the shallower joint, mainly in the CM group (92.9%); and type III, the abnormal flat-tilt joint, mainly in the CM + II-BI group (89.3%). Kinematic computed tomography revealed AOI in all III-AOJs (100%) and some II-AOJs (1.5%) but not in type I-AOJs (0%). Morphological parameters of the superior portion of C1-LM positively correlated with those of C0 and the clivus and significantly correlated with AOI.

Conclusion

Dysplasia of the condyle and superior portion of C1-LM exists in both CM and II-BI cases yet is more obvious in type II-BI. Unstable movement caused by AOJ deformation is another pathogenic factor in patients with CM + II-BI.

SUBMITTER: Huang Q

PROVIDER: S-EPMC9988292 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature

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Publications

Exploring the Pathogenesis of Atlanto-Occipital Instability in Chiari Malformation With Type II Basilar Invagination: A Systematic Morphological Study.

Huang Qinguo Q Yang Xiaoyu X Zheng Dongying D Zhou Qiang Q Li Hong H Peng Lin L Ye Junhua J Qi Songtao S Lu Yuntao Y Lu Yuntao Y

Neurosurgery 20221216 4

<h4>Background</h4>Our previous study suggested that atlanto-occipital instability (AOI) is common in patients with type II basilar invagination (II-BI).<h4>Objective</h4>To further understand the pathogenesis of AOI in Chiari malformations (CM) and CM + II-BI through systematic measurements of the bone structure surrounding the craniocervical junction.<h4>Methods</h4>Computed tomography data from 185 adults (80 controls, 63 CM, and 42 CM + II-BI) were collected, and geometric models were establ ...[more]

PMID: 36700733

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Project description:IntroductionThe fibrous posterior atlanto-occipital membrane (PAOM) at the craniocervical junction is typically removed during decompression surgery for Chiari malformation type I (CM-I); however, its importance and ultrastructural architecture have not been investigated in children. We hypothesized that there are structural differences in the PAOM of patients with CM-I and those without.MethodsIn this prospective study, blinded pathological analysis was performed on PAOM specimens from children who had surgery for CM-I and children who had surgery for posterior fossa tumors (controls). Clinical and radiographic data were collected. Statistical analysis included comparisons between the CM-I and control cohorts and correlations with imaging measures.ResultsA total of 35 children (mean age at surgery 10.7 years; 94.3% white) with viable specimens for evaluation were enrolled: 24 with CM-I and 11 controls. There were no statistical demographic differences between the two cohorts. Four children had a family history of CM-I and five had a syndromic condition. The cohorts had similar measurements of tonsillar descent, syringomyelia, basion to C2, and condylar-to-C2 vertical axis (all p>0.05). The clival-axial angle was lower in patients with CM-I (138.1 vs. 149.3 degrees, p = 0.016). Morphologically, the PAOM demonstrated statistically higher proportions of disorganized architecture in patients with CM-I (75.0% vs. 36.4%, p = 0.012). There were no differences in PAOM fat, elastin, or collagen percentages overall and no differences in imaging or ultrastructural findings between male and female patients. Posterior fossa volume was lower in children with CM-I (163,234 mm3 vs. 218,305 mm3, p<0.001), a difference that persisted after normalizing for patient height (129.9 vs. 160.9, p = 0.028).ConclusionsIn patients with CM-I, the PAOM demonstrates disorganized architecture compared with that of control patients. This likely represents an anatomic adaptation in the presence of CM-I rather than a pathologic contribution.

Project description:Fibrous dysplasia (FD) is a mosaic disorder of benign fibro-osseous lesions, which may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). Cranial base abnormalities, including Chiari I malformation (CM1), in which the cerebellum extends below the foramen magnum, and secondary basilar invagination (BI), in which the odontoid prolapses into the posterior cranial fossa, are potentially serious complications of metabolic bone disorders. The purpose of this study was to determine the prevalence, natural history, and risk factors for CM1 and BI in patients with FD/MAS, and to determine mechanisms of cranial base deformities. Clinical and radiographic data from subjects in an FD/MAS natural history study were evaluated and compared to normal controls. In 158 patients with craniofacial FD, 10 (6.3%) cases of CM1 and 12 (7.6%) cases of BI were diagnosed. No cranial base abnormalities were identified in 10 control subjects. Craniomorphometric and volumetric analyses identified cranial constriction and cranial settling as the primary mechanisms of cranial base abnormalities, whereas intracranial hypertension was a contributing factor in a minority of subjects. Longitudinal analyses found progression of odontoid position with age, but no progression of tonsillar position. No endocrinopathies were associated with CM1. MAS endocrinopathies associated with BI included hyperthyroidism (odds ratio [OR] 12.0; 95% confidence interval [CI], 2.9 to 55.6; p?<?0.01), precocious puberty (OR 5.6; 95% CI, 1.2 to 26.0; p?<?0.05), and hypophosphatemia (OR 7.7; 95% CI, 1.9 to 27.0; p?<?0.01). Scoliosis was associated with both CM1 (OR 4.8; 95% CI, 1.1 to 22.8; p?<?0.05) and BI (OR?=?infinity; 95% CI, 4.7 to infinity; p?<?0.01). This study successfully characterized cranial base abnormalities in FD/MAS and the pathophysiological connection between them. These findings support routine screening for cranial base abnormalities in patients with craniofacial FD, as well as aggressive management of contributory risk factors. © 2018 American Society for Bone and Mineral Research.

Project description:ObjectiveTo investigate the cervical alignment and the relative range of motion (ROM) in patients with basilar invagination (BI).MethodsA total of 40 BI cases (38.1 years old ± 17.9 years old, 19 male and 21 female) and 80 asymptomatic individuals (33.8 years old ± 10.8 years old, 40 male and 40 female) were included. The Skull-C2 /Skull-BV, Skull-C7 , C2 -C7 /BV-C7 wall angles, C0 -C2 /C0 -BV, C0 -C7 , C1 -C7 , and C2 -C7 /BV-C7 angles were measured in dynamic X-ray images (including neutral, extension, and flexion positions). Correlation between the upper and lower cervical curvatures were analyzed. The total, extension, and flexion ROMs of these angles were calculated, respectively.ResultsThe BI patients had a smaller C0 -C2 /C0 -BV angle (18.2° ± 16.4° vs 30.9° ± 9.3°), but larger C2 -C7 /BV-C7 (32.2° ± 16.1° vs 19.4° ± 10.6°) and C2 -C7 /BV-C7 wall angles (37.8° ± 17.2° vs 23.6° ± 10.2°) than the control group in neutral position. The upper and lower curvatures correlated negatively in neutral (r = -0.371), extension (r = -0.429), and flexion (r = -0.648) positions among BI patients, as well as in extension position (r = -0.317) among control group. The BI patients presented smaller total ROMs in Skull-C2 /Skull-BV (12.3° ± 16.6° vs 19.7° ± 10.9°), C0 -C2 /C0 -BV (8.1° ± 11.1° vs 17.6° ± 10.5°), and C0 -C7 angles (57.8° ± 14.2° vs 78.3° ± 17.9°), but a larger total ROM in C2 -C7 /BV-C7 wall angle (52.8° ± 13.9° vs 27.0° ± 16.1°) than the control group. The BI patients also presented smaller extension ROMs in Skull-C2 /Skull-BV (6.9° ± 9.4° vs 12.5° ± 9.3°), Skull-C7 (24.5° ± 10.9° vs 30.7° ± 12.5°), and C0 -C2 /C0 -BV angles (4.4° ± 7.8° vs 9.9° ± 8.6°) than the control group. Moreover, the BI patients showed smaller absolute values of flexion ROMs in Skull-C2 /Skull-BV (-5.2° ± 9.4° vs -7.3° ± 8.0°), C0 -C2 /C0 -BV (-3.2° ± 8.8° vs -7.7° ± 8.7°), and C0 -C7 angles (-33.2° ± 13.0° vs -52.8° ± 19.2°), but a larger absolute value of flexion ROM in C2 -C7 /BV-C7 wall angle (-33.9° ± 14.8° vs -8.2° ± 15.1°).ConclusionThe cervical spine was stiffer in BI patients than the asymptomatic individuals, especially in the upper cervical curvature. The negative correlation between upper and lower cervical curvatures was more obvious in BI patients.

Project description:BackgroundTraumatic occipitocervical dislocations (OCDs) are rare and potentially devastating injuries, and delayed diagnosis and management is a well-known risk factor for poor outcomes in high energy trauma. Early surgical stabilization has been shown to improve outcomes and neurologic recovery in these patients. We present a case of incongruent atlanto-occipital (O-C1) joints found on post-operative computed tomography (CT) imaging following C1-C2 fusion. This patient was treated non-operatively in a cervical collar (C-collar) after traction testing revealed no dynamic instability.Case descriptionA 19-year-old male with history of obesity was involved in a high-speed motor vehicle collision (MVC). On arrival, he had elevated troponins but otherwise normal laboratory workup and electrocardiogram (EKG). He remained hypotensive throughout his initial presentation. A reliable neurologic exam could not be obtained due to the patient's intubated and sedated status, however, bulbocavernosus reflex was intact, reflexes were normal and the patient did not demonstrate evidence of spinal or neurogenic shock. CT of the full spine revealed distraction of the C1-C2 articulation without associated fracture, and without clear disruption or distraction of the O-C1 joint. He was taken to the operating room for C1-C2 posterior instrumentation and fusion. Post-operative cervical spine CT revealed further distraction and subluxation of the occipitocervical junction bilaterally, with condyle to C1 interval (CCI) of 4-mm bilaterally, a basion-dens interval (BDI) of 10 mm, and a Power's Ratio of 1.1. The patient was brought back urgently to the operating room for traction testing to rule out OCD. There was no distraction noted on dynamic traction testing, and the patient was treated non-operatively in a C-collar. At 12 weeks post-injury, the patient experienced no neck pain, and flexion/extension radiographs showed no evidence of subluxation or distraction at the O-C1 joints.ConclusionsIncongruity of the O-C1 joint may not be synonymous with instability as previously thought, and in cases of O-C1 incongruity with stable traction testing, non-operative treatment with external immobilization can be considered as a viable treatment option even in the polytraumatized patient.

Dataset Information

Exploring the Pathogenesis of Atlanto-Occipital Instability in Chiari Malformation With Type II Basilar Invagination: A Systematic Morphological Study.

Background

Objective

Methods

Results

Conclusion

Publications

Exploring the Pathogenesis of Atlanto-Occipital Instability in Chiari Malformation With Type II Basilar Invagination: A Systematic Morphological Study.

Similar Datasets

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