Basilar Invagination

INTRODUCTION: Atlanto-occipital assimilation is the most common osseous anomaly of the cervical-occipital junction. The incidence rate of occipitalization has been reported 1.42.5/1000 children. Most of the patients are asymptomatic initially. Clinical features usually appear after 3rd decade depending on the level and degree of spinal cord compression with surrounding vital structures such as vertebral artery involvement. Hence, early definitive diagnosis and subsequent successful treatment are necessary in such cases to prevent life-threatening complications...

Objectives and Background : To present a novel technique of treatment for a patient with basilar invagination. Basilar invagination (BI) is a congenital condition that can compress the cervicomedullary junction, leading to neurological deficits. Severe cases require surgical intervention, but there is debate over the choice of approach. The anterior approach allows direct decompression but carries high complication rates, while the posterior approach provides indirect decompression and offers good stability with fewer complications...

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A Chiari I malformation is a frequently encountered anomaly of the posterior fossa, occurring in a notable percentage of the population. It often coexists with various other craniovertebral junction abnormalities, albeit less frequently with Klippel-Feil syndrome. Interestingly, the majority of individuals with Chiari I malformation do not exhibit any symptoms. We present a rare case of a 25-year-old male with chronic neck and occipital pain, along with progressive weakness and sensory disturbances in all four limbs, urinary urgency, and elevated left shoulder...

Secondary basilar invagination or basilar impression is an anomaly at the craniovertebral junction where the odontoid process prolapses into the foramen magnum with the risk of compressing adjacent structures and obstructing the proper flow of cerebrospinal fluid (CSF). The incidence is less than 1% in the general population and occurs mainly in the first three decades of life when it is associated with malformations of the neuroaxis. In older age, the main aetiologies are diseases that alter bone mineral density...

OBJECTIVE: Basilar invagination is one of the most frequently observed abnormalities at the craniovertebral junction, in which the odontoid process of C2 prolapses into the foramen magnum. METHODS: The current study included 27 patients who underwent surgery for basilar invagination between October 2013 and January 2023. The study group was divided into 2 groups according to basilar invagination types; type I (the presence of type A atlantoaxial instability and instability is the main pathology) and type II (the presence of type B and C atlantoaxial instability and skull base dysgenesis is the main pathology)...

OBJECTIVE: Recent years have witnessed a rapidly growing interest in CVJ bony abnormalities, and a qualitative and quantitative analysis of relevant literatures is necessary. This study aims to identify and summarize the published articles related to craniovertebral junction bony abnormalities, to analyze and visualize the current research trends and major contributors. METHODS: We collected data from Web of Science, excluding certain article types. Two researchers screened articles for relevance...

The craniovertebral junction not only contains anatomically important structures such as the medulla oblongata, upper cervical spinal cord, and vertebral artery, but also controls the dynamic movements of flexion, extension, and rotation of the head and neck. Consequently, instability and spinal deformities can easily occur in the craniovertebral region, and appropriate treatment should be selected based on the specificity of the lesion. Basilar invagination often involves bone and vascular anomalies and fusion surgery is often required...

In 1994, the use of interfacet spacer placement was for joint distraction, reduction, and fusion to supplement atlantoaxial or occipitocervical fixation. Here, we present a unique case of bilateral atlantoaxial interfacet fixation using cervical facet cages (CFC) in a pediatric patient with basilar invagination. In addition, we review the literature on atlantoaxial facet fixation. We present a 12-year-old boy with Wiedemann-Steiner syndrome who presented with multiple episodes of sudden neck jerking, described as in response to a sensation of being shocked, and guarding against neck motion, found to have basilar invagination with cervicomedullary compression...

BACKGROUND: The treatment of vertebrobasilar junction (VBJ) aneurysms is challenging. Although flow diverters (FDs) are a possible treatment option, geometrical conditions hinder intervention. VBJ aneurysms possess dual inflow vessels from the bilateral vertebral arteries (VAs), one of which is ideally occluded prior to FD treatment. However, it remains unclear which VA should be occluded. OBSERVATIONS: A 75-year-old male with a growing VBJ complex aneurysm exhibiting invagination toward the brainstem and causing perifocal edema required intervention...

BACKGROUND: Chiari malformation type 1 (CM1) is a congenital hindbrain malformation characterized by herniation of the cerebellar tonsils below the foramen magnum. The term Chiari type 1.5 is used when herniation of the brainstem under the McRae line and anomalies of the craniovertebral junction are also present. These conditions are associated with several symptoms and signs, including headache, neck pain, and spinal cord syndrome. For symptomatic patients, surgical decompression is recommended...

BACKGROUND Previous radiographic measurements for diagnosis of a basilar invagination or impression (BI) in rheumatoid arthritis (RA) were used as reference values based on anatomical reference distances. Due to the obscured anatomical landmarks, our group proposed a new radiographic measurement based on anatomic ratios to identify BI. MATERIAL AND METHODS The vertical relationship ratio (VRR) was developed and evaluated. The VRR is the relationship between the distance obtained with the modified Ranawat method and the C3 vertebral body height...

Multiple primary intracranial tumors, or the presence of two or more primary intracranial tumors, are a rare clinical occurrence. The current study presents the case of a 28-year-old patient with concurrent left vestibular schwannoma, left cerebellar hemisphere dermoid cyst and craniovertebral junction malformation, specifically basilar invagination and Klippel-Feil syndrome. The patient exhibited symptoms of torticollis and recurrent headaches, with no apparent hearing loss. A far lateral approach was selected for surgical resection to address these complex conditions and achieve gross total resection in a single-stage surgery while preserving both facial and auditory nerve function...

Understanding the anatomy of the vertebral artery is essential while manipulating the craniovertebral joint during surgery. Its anomalous course in congenital atlantoaxial dislocation makes it more vulnerable to injury. Preoperative dedicated computed tomography (CT) angiography helps identify the artery's position and plan for surgical procedure. A 13-year-boy presented with neck pain and spastic quadriparesis for 1 year. Radiological imaging of the craniovertebral junction revealed atlantoaxial instability with basilar invagination...

Basilar invagination (BI) is characterized by rostral dislocation of the cervical spine toward the skull base. The craniometrics of the skull base have shown significant differences among craniocervical junction malformations. The sphenoid bone is the center of the skull base; however, no study has evaluated this bone in cases of BI. This was a cross-sectional study of MRI databanks from two institutions of the author's practice between 1985 and 2020. The craniometrics of the sphenoid bone were measured in BI patients and controls...

BACKGROUND: Hajdu-Cheney syndrome (HCS) is an extremely rare genetic disorder characterized by severe osteoporosis, scoliosis, and persistent open cranial sutures (POCSs). Neurological complications include hydrocephalus, Chiari I malformations, and basilar invagination (BI). Surgical intervention in HCS is challenging due to severe osteoporosis, ligamentous laxity, POCSs, and extreme skeletal deformities. Herein, the authors present a case of BI repair in a patient with HCS and POCSs, requiring a novel technique of cranial vault suspension, with long-term follow-up...

BACKGROUND AND AIM: Direct posterior reduction and manipulation of the C1-2 joints, accompanied by placement of spacers, is the state-of-the-art technique for treating basilar invagination (BI) and atlantoaxial dislocation (AAD). The hindrance of occiput to reaching up to the true atlantoaxial facets (AAF) during the surgery remains challenging for cage placement. The aim of this study was to explore an objective and precise method of measuring the effect of the hindrance of occiput to reaching up to the true AAF and cage placement during surgery...

OBJECTIVE: Pathological bony abnormalities of the craniocervical region in children sometimes require surgical intervention as part of their management. Rarely, abnormal skeletal or vascular anatomy can render traditional surgical techniques ineffective because of the risk of injury to the vertebral artery. To mitigate these risks, a combined endovascular and skull base approach was devised. The authors describe their experience using vertebral artery sacrifice as an adjunctive surgical method to reduce the risk of inadvertent vertebral artery injury during surgical correction of pediatric craniocervical deformity...

Chiari type 1 malformation (CIM) is defined as tonsillar ectopia of >5 mm, while syringomyelia (SM) is defined as a cerebrospinal fluid (CSF)-filled cavity larger than 3 mm dissecting the spinal cord. Over the last decades, our understanding of these pathologies has grown; however, many controversies still exist almost in every aspect of CIM and SM, including etiology, indication for treatment, timing of treatment, surgical technique, follow-up regime, and outcome. This chapter provides a comprehensive overview on different aspects of CIM and SM and on the still existing controversies, based on the evidence presently available...

Cranio-cervical junction (CVJ) anomalies encompass a spectrum of bone,soft tissue,and neural structural abnormalities,including basilar invagination,platybasia,atlantoaxial dislocation,tonsillar herniation,and occipito-cervical fusion.Given the frequent coexistence of these anomalies and the intricate anatomical variations involved,precise imaging techniques and evaluation parameters are crucial for accurate disease characterization and treatment assessment.Since the 1930s,various parameters,such as the McRae line,Chamberlain line,Wackenheim line,and clivo-axial angle,have been widely employed for evaluating basilar invagination and platybasia...