Complex posterior atlantoaxial instability in pediatric os odontoideum: A novel stabilization strategy.

Introduction: Os odontoideum (OO) is a rare anatomic variant of the axis characterized by the separation of a part of the axis. It may cause cervical instability, atlantoaxial dislocation, myelopathy, or permanent paralysis. We present an extremely rare case of an OO with posterior atlantoaxial dislocation in a child.

Traumatic posterior atlantoaxial dislocation without an associated fracture: a PRISMA-compliant case-based systematic review and meta-analysis.

Traumatic posterior atlantoaxial dislocation (TPAD) without an associated fracture is a rare and challenging spinal injury. This PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)-compliant case-based systematic review and meta-analysis aimed to comprehensively explore TPAD, covering clinical presentation, diagnosis, treatment, and clinical and radiological outcomes. Following the presentation of a case of TPAD without an associated fracture, we conducted a systematic search of electronic databases, including Scopus, PubMed, and Web of Science, from inception through October 2023, without language restrictions.

Clinical features and outcomes of basilar invagination.

Basilar invagination has been classified into two types by Goel: Type A is defined mechanical instability of the atlantoaxial joint with upward displacement of the odontoid process while Type B is characterized by stable atlantoaxial joints. This study reviews the association between radiological features and symptomatology and prognosis of two types of basilar invagination for better clinical management. A retrospective analysis was conducted including 141 patients diagnosed with basilar invagination who underwent surgical treatment from January 2016 to December 2020.

Navigated Osteosynthesis for Unstable Atlas Fractures: Technical Note and Case Series.

Objective: Fractures of the atlas are typically considered stable or unstable based on the integrity of the transverse ligament. Whereas stable Jefferson burst fractures can be treated nonoperatively, unstable fractures with disruption of the transverse ligament often require surgical intervention. Atlas osteosynthesis has been proposed as a motion-preserving alternative to atlantoaxial fusion.

The Change of Asymptomatic Atlantoaxial Instability With Down Syndrome From Infant to Adolescent in Japanese Population: Minimum 10 Years Follow-Up.

Background: Although 10% to 60% of patients with Down syndrome (DS) develop atlantoaxial instability (AAI), clarifying the course of asymptomatic AAI may prevent unnecessary clinical interactions and investigations. This study investigates the radiographic changes observed in asymptomatic AAI associated with DS in Japanese children as they grow from infancy to adolescence over a minimum of 10 years.

Methods: A retrospective analysis of cervical radiographs acquired from asymptomatic patients with DS in both infancy and adolescence was carried out.

Axis screw parallel to the sagittal plane versus traditional pedicle screw in the treatment of atlantoaxial fixation: a finite element study.

Background: This study aims to conduct a finite element analysis (FEA) to assess the bio-mechanical properties of C2 sagittal-parallel pedicle screw (PPS) in fixation for atlantoaxial instability, thereby providing a theoretical foundation for its clinical application.

Methods: A total of 5 intact C1-2 finite element models were established. Based on this, instability models were developed and two different fixation methods were applied for each model: C1 lateral mass screw (LMS) combined with C2 sagittal-parallel pedicle screw (C1LMS + C2PPS), and C1 lateral mass screw combined with C2 traditional pedicle screw (C1LMS + C2PS).

General Anesthetic Management of a Patient With Spondyloepiphyseal Dysplasia Congenita Undergoing Palatoplasty Revision.

Spondyloepiphyseal dysplasia congenita (SEDC) is a type of short-limbed dwarfism characterized by platyspondylia, delayed metaphyseal ossification, and irregularly shaped bones. Anesthetic issues in patients with SEDC have reportedly included airway stenosis caused by laryngotracheal hypoplasia, ventilation difficulty due to facial hypoplasia, and intubation difficulty attributed to microgenia. Furthermore, atlantoaxial instability can lead to cervical dislocation due to excessive or violent manipulation of the head and neck.

Dystopic Os Odontoideum With Chronic Posterior Atlantoaxial Subluxation: A Case Report.

Os odontoideum is considered a rare cervical spine anomaly. Depending on its type, it may or may not result in atlantoaxial instability, which can lead to anterior subluxation (the most common type) or posterior subluxation, with the latter being extremely rare. Posterior atlantoaxial subluxation is particularly dangerous, as it can progressively lead to myelopathy through various mechanisms and may ultimately result in quadriplegia or even death.

Rotation Preserving Fixation for the Treatment of C1 Burst Fracture Combined With Type II Odontoid Fracture: 2 Case Reports and Literature Review.

Objective: This study aimed to evaluate the clinical feasibility and effectiveness of a monoaxial screw-rod system and anterior screw fixation for C1 and type II odontoid fractures.

Methods: We conducted a retrospective review of 2 consecutive patients with acute C1 and Anderson-D'Alonzo type II odontoid fractures. Both patients underwent treatment using a posterior monoaxial screw-rod system and anterior screw fixation.

Atlantoaxial Instability due to Os Odontoideum in a Child with Christianson Syndrome.

Introduction: Christianson syndrome is a rare neurodevelopmental disorder associated with mutations in the gene located on the chromosome X. It is characterized by intellectual disability, developmental delay, speech and language impairments, dysmorphic features, seizures, ataxia, and neurobehavioral problems.

Case Presentation: A 5-year-old boy was presented with respiratory failure and then progressive muscle weakness in all four extremities.

A novel technique for C1-C2 posterior screw insertion using patient-specific guides created by CT-based 3D printing.

C1-C2 fixation has been developed for the rigid fusion of atlantoaxial instability. C1 lateral mass screw (C1 LMS)-C2 pedicle screw fixation is used more frequently due to its rigid fixation and high bone fusion rate. However, C1 screw placement is relatively unsafe even with recently developed image-based navigation systems.

Addressing the challenges of complex type III odontoid fractures: Clinical and radiological outcomes of various treatment modalities.

Background: Unlike simple fractures, complex Type III odontoid fractures-characterized by intricate morphology and pathomechanics-pose significant management challenges. This study aims to evaluate the clinical and radiological outcomes of conservative and surgical treatment modalities for these complex fractures, with a focus on assessing factors influencing fracture union.

Methods: Following approval of our institutional review board, this retrospective observational cohort study was conducted.