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In the present study, the most commonly observed types of occipital condyles were oval, followed by circular and two-portioned shapes. Occipital condyles are small bilateral extensions of the occipital bone that hold crucial implications for neurosurgical practice due to their association with various disease processes affecting the craniovertebral junction. A comprehensive understanding of the bony anatomy and variations in occipital condyles is imperative for optimising neurosurgical approaches. The primary objective of this study is to conduct an in-depth investigation of occipital condyles. We examined 40 dry human skulls, meticulously measuring various parameters such as length, breadth, anterior, and posterior intercondylar distances. The shapes of occipital condyles were classified into distinct types: oval, circular, eight-shaped, kidney-shaped, deformed, two-portioned, oval convex, and pyramid. The documented parameters of occipital condyles and their variations are poised to serve as invaluable guidelines for future surgeons. Possessing a thorough understanding of occipital condyle morphometry can significantly facilitate the instrumentation process, mitigating the risk of neurovascular damage. We firmly believe that the outcomes of our research will establish a comprehensive reference database, aiding in the development of implants and the formulation of optimal surgical approaches tailored to the intricacies of occipital condyles. [ABSTRACT FROM AUTHOR]

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An 8-month-old, 3.4 kg, castrated male Toy Poodle was referred for progressive tetraparesis and respiratory disorder without a history of trauma. Repeated computed tomography (CT) and magnetic resonance imaging (MRI) with different positions of the neck revealed concurrent atlanto-occipital dislocation (AOD) and atlantoaxial instability (AAI) with spinal cord compression. This case was unique due to its congenital nature and the absence of trauma. The surgical treatment involved precise removal of the C1 vertebra’s ventral articular facet, which was compressing on the spinal cord, attributed to its fixed and malaligned position within the atlantooccipital joint. Following facetectomy, the stabilization of the occipital bone to the C2 vertebra was achieved by screws, wire, and polymethyl methacrylate. Two days after surgery, the dog recovered ambulation and showed gradual improvement in gait, despite mild residual ataxia. Postoperative CT and radiographs showed successful decompression of the spinal cord. The screw loosening was confirmed at 114 days, which was managed successfully by extracting the affected screws. Through the 21-month monitoring period, the dog showed a normal gait with a wide-based stance of the pelvic limbs when standing and experienced no pain. This case represents the first report of concurrent congenital AOD and AAI treated with a ventral surgical approach, contributing new insights to the understanding and management of such complex cranio-cervical junction disorders in veterinary neurosurgery.

Down syndrome, also known as trisomy 21, is associated with congenital cervical spine abnormalities, including atlantoaxial instability with or without os odontoideum, atlanto-occipital instability, and hypoplasia of the atlas. Herein, we report a case of Down syndrome complicated by congenital atlanto-occipital dislocation. The patient presented with severe cervical myelopathy at 13 years of age after a 10-year follow-up. Radiography and computed tomography revealed os odontoideum protruding into the foramen magnum and congenital anterior atlanto-occipital dislocation. Additionally, a bifurcated internal occipital crest with a thinned central portion of the occipital bone was noted. Magnetic resonance imaging revealed kyphotic alignment of the spinal cord with severe compression at the foramen magnum level. As the neurological impairment was partially improved by halo vest immobilization, we performed in situ O-C2 fusion with an iliac autograft and decompression of the foramen magnum and posterior arch of C1. An improvement was observed immediately after surgery. Two years after surgery, radiography and computed tomography showed solid O-C2 segment fusion. The accumulation of similar cases is essential for determining the prognosis or optimal treatment for this rare congenital condition. [ABSTRACT FROM AUTHOR]

Atlanto-occipital dislocation (AOD) is an injury to the upper cervical spine that occurs after trauma. This injury is associated with a high mortality rate. According to studies, 8%–31% of deaths caused by accidents are due to AOD. Due to the improvement in medical care and diagnosis, the rate of related mortality has decreased. Five patients with AOD were evaluated. Two cases had type 1, one case had type 2, and two other patients had type 3 AOD. All patients had weakness in the upper and lower limbs and underwent surgery to fix the occipitocervical junction. Other complications in patients were hydrocephalus, 6 nerve palsy, and cerebellar infarction. All patients improved in follow-up examinations. AOD damage is divided into four groups: anterior, vertical, posterior, and lateral. The most common type of AOD is type 1 and the most instability is type 2. There are neurological and vascular injuries due to pressure on regional components; vascular injuries are associated with high mortality rate. In most patients, their symptoms improved after surgery. AOD requires early diagnosis and immobilization of the cervical spine along with maintaining the airway to save the patient's life. It is necessary to consider AOD in cases with neurological deficits or loss of consciousness in the emergency unit because earlier diagnosis could cause a wonderful improvement of the patient's prognosis.

Atlanto-occipital dislocation (AOD) is an injury to the upper cervical spine that occurs after trauma. This injury is associated with a high mortality rate. According to studies, 8%–31% of deaths caused by accidents are due to AOD. Due to the improvement in medical care and diagnosis, the rate of related mortality has decreased. Five patients with AOD were evaluated. Two cases had type 1, one case had type 2, and two other patients had type 3 AOD. All patients had weakness in the upper and lower limbs and underwent surgery to fix the occipitocervical junction. Other complications in patients were hydrocephalus, 6 nerve palsy, and cerebellar infarction. All patients improved in follow-up examinations. AOD damage is divided into four groups: anterior, vertical, posterior, and lateral. The most common type of AOD is type 1 and the most instability is type 2. There are neurological and vascular injuries due to pressure on regional components; vascular injuries are associated with high mortality rate. In most patients, their symptoms improved after surgery. AOD requires early diagnosis and immobilization of the cervical spine along with maintaining the airway to save the patient's life. It is necessary to consider AOD in cases with neurological deficits or loss of consciousness in the emergency unit because earlier diagnosis could cause a wonderful improvement of the patient's prognosis. [ABSTRACT FROM AUTHOR]

Objective. To review the literature on atlanto-occipital dislocation (AOD) in adults to determine the optimal classification, diagnostic method and treatment. Material and Methods. A search was conducted in the PubMed database for the period from 1966 to 2020. The initial search revealed 564 abstracts of articles. A total of 95 studies were selected for a detailed study of the full text, of which 47 studies describing data from 130 patients were included in this review. Results. The paper describes all the available AOD classifications, and discusses their advantages and disadvantages. The clinical picture, features of the diagnosis in published observations of AOD in adults, as well as the applied treatment methods and their results are presented. Conclusion. Atlanto-occipital dislocation is one of the most severe types of injuries of the cervical spine in adults, which is accompanied by damage to the medulla oblongata and gross neurological deficit in 70 % of cases. The sensitivity of radiography for the diagnosis of AOD was 56.3 %. In 18.5 % of patients, its use led to untimely diagnosis and could cause subsequent deterioration. The CT sensitivity was 96.8 %. The most accurate method of AOD verification was to determine the atlanto-occipital interval (100 % sensitivity and specificity). The optimal method of treating victims with AOD is surgical one.

Traumatic atlanto-occipital dislocation (TAOD) are uncommon injuries associated with high immediate mortality rate and occurs more than twice in children than adults, due to biomechanical properties and immaturity of children's cervical spine. We report a pediatric patient with TAOD, who underwent occipitocervical stabilization and also developed a late hydrocephalus requiring a shunt procedure. A six-year-old boy was admitted to the emergency department after a car accident with refractory cervical pain. A cervical computed tomography (CT) scan showed an anterior C1–C2 level hematoma, and a dynamic CT scan demonstrated an increasing basion-dens interval on extension. Cervical magnetic resonance imaging (MRI) showed discontinuity of the tectorial membrane and diffused hyperintense signal on the left alar ligament. These findings were attributed to TAOD, and an occipitocervical fusion was performed. The pain and neurological status improved after surgery, but after 3 months he returned with persistent vomiting, headache, and a CT scan showing hydrocephalus. Then, a ventriculoperitoneal shunt was performed, improving the symptoms. One year after the injury, the patient remained asymptomatic, and a later radiography demonstrated satisfactory bone fusion. In conclusion, the decision-making process regarding treatment should consider several clinical and radiographic findings. Occipitocervical fusion is the treatment of choice, while hydrocephalus is not an unusual complication in children.

The objectives of this study were to conduct a systematic review of the literature to determine the optimal treatment method for patients with atlanto-occipital dislocation (AOD) and to identify possible factors influencing their outcomes. We conducted a systematic review of the PubMed database between January 1966 and December 2020. The main inclusion criterion was articles that discussed AOD treatment methods, and outcome descriptions were selected for analysis. Intergroup differences were assessed using nonparametric statistical methods. Of the 657 articles identified initially, only 54 met the inclusion criteria, resulting in data from 139 patients. Type I or II AODs were more frequent in patients injured in road traffic accidents, whereas type III AODs were more frequent in patients with catatrauma (P = 0.027). Spinal cord injury was more frequently observed in patients with types I and II AODs than in those with type III AOD (P = 0.026). Improved outcomes were more common in the surgical treatment group (P < 0.001). Significant differences in treatment outcomes between the halo device and orthosis groups were not observed (P = 0.32). Prognosis of AOD is unfavorable in adults with dislocations resulting from road traffic accidents, those with types I and II AOD, and patients younger than 22 years and older than 47 years. Surgical treatment was optimal for adult patients with an AOD, and treatment outcomes did not depend on the number of occipitocervical fusion levels. Immobilization with the halo device showed no advantages over use of an external orthosis. [ABSTRACT FROM AUTHOR]

Background: Traumatic atlanto-occipital dislocation is an unstable injury of the craniocervical junction. For pediatric patients, surgical arthrodesis of the occipitocervical junction is the recommended management. While having a high success rate for stabilization, the fusion comes with obvious morbidity of limitation in cervical spine flexion, extension, and rotation. An alternative is external immobilization with a conventional halo. Case Description: We describe the case of a 10-year-old boy who was treated successfully for traumatic AOD with a noninvasive pinless halo. Following initial brain trauma management, we immobilized the craniocervical junction with a pinless halo after reducing the atlanto-occipital dislocation. The pinless halo was kept on at all times for the next 3 months. The craniocervical junction alignment was monitored with weekly cervical spine X-rays and CT craniocervical junction on day 15th, day 30th, and day 70th. A follow-up MRI C-spine 3 months from presentation confirmed resolution of the soft-tissue injury and the pinless halo was removed. Dynamic cervical spine X-rays revealed satisfactory alignment in both flexion and extension views. The patient has been followed up for 2 years postinjury and no issues were identified. Conclusion: Noninvasive pinless halo is a potential treatment option for traumatic pediatric atlanto-occipital dislocation. This should be considered bearing in mind multiple factors including age and weight of the patient, severity of the atlanto-occipital dislocation (Grade I vs. Grade II and incomplete vs. complete), concomitant skull and scalp injury, and patient's ability to tolerate the halo. It is vital to emphasize that this necessitates close clinicoradiological monitoring. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to describe the findings of traumatic atlanto-occipital dislocation (AOD) on cervical spine CTs and differences leading to varying treatment of these patients. Methods: We retrospectively identified 20 adult patients with AOD from cervical spine CTs demonstrating fracture or fracture dislocations over 19 years at 2 major trauma centers. Medical records were reviewed and craniovertebral junction (CVJ) metrics measured on CT. Intubation, Glasgow Coma Scale (GCS), additional injuries, occiput/atlas/axis fracture, concurrent atlantoaxial subluxation, vascular injury on CT angiography, and ligamentous injury on MRI were noted. Results: Using the Traynelis Classification, eight patients had type 2 and eight patients type 3 AOD. Four of 5 patients who died within 14 days of CT had type 2 AOD. Three patients had medial/lateral AOD. Of the patients who survived initial injuries, a greater percentage who underwent surgical or halo fixation versus non-operatively treated patients had abnormal CVJ measurements including BDI (62.5% vs 0%), atlantoaxial subluxation (75% vs 14.3%), ligamentous injury (80% vs 66.7%), intubation (62.5% vs 28.6%), GCS<8 (62.5% vs 14.3%), and additional injuries (75% vs 71.4%) on presentation. MRI helped identify 2 cases of type 2 AOD and surgical decision making in 8 cases. Conclusions: Types 2 and 3 were the most common, and type 2 is the deadliest type of AOD. A greater proportion of patients who undergo surgical or halo fixation have abnormal CT/MR findings with neurologic impairment at presentation. MRI aided detection of potentially missed type 2 AOD and was critical for surgical decision making. [ABSTRACT FROM AUTHOR]

A 39-year-old male pedestrian-hit-by-car was transferred to our institution with atlantooccipital dislocation (AOD) on outside computed tomography (CT) imaging. On arrival he had a rigid cervical collar in place. Given the reported AOD, we placed the patient flat, removed the cervical collar, and supported the head in neutral alignment with sandbags. Due to a technical issue uploading his prior imaging to our system, the patient underwent repeat CTs at our center. Subsequently, after the outside images were uploaded, we were able to compare his cervical spine CT images before and after removing his cervical collar. On comparison, we noted a substantial reduction in AOD after collar removal. We hope this serves as a reminder of this key step in managing a rare but deadly clinical entity and a small demonstration of the efficacy of this intervention. [ABSTRACT FROM AUTHOR]

An 8-month-old, 3.4 kg, castrated male Toy Poodle was referred for progressive tetraparesis and respiratory disorder without a history of trauma. Repeated computed tomography (CT) and magnetic resonance imaging (MRI) with different positions of the neck revealed concurrent atlanto-occipital dislocation (AOD) and atlantoaxial instability (AAI) with spinal cord compression. This case was unique due to its congenital nature and the absence of trauma. The surgical treatment involved precise removal of the C1 vertebra's ventral articular facet, which was compressing on the spinal cord, attributed to its fixed and malaligned position within the atlantooccipital joint. Following facetectomy, the stabilization of the occipital bone to the C2 vertebra was achieved by screws, wire, and polymethyl methacrylate. Two days after surgery, the dog recovered ambulation and showed gradual improvement in gait, despite mild residual ataxia. Postoperative CT and radiographs showed successful decompression of the spinal cord. The screw loosening was confirmed at 114 days, which was managed successfully by extracting the affected screws. Through the 21-month monitoring period, the dog showed a normal gait with a wide-based stance of the pelvic limbs when standing and experienced no pain. This case represents the first report of concurrent congenital AOD and AAI treated with a ventral surgical approach, contributing new insights to the understanding and management of such complex cranio-cervical junction disorders in veterinary neurosurgery.

Background: The correct diagnosis and treatment of the atlanto-occipital dislocation (AOD) remains a major challenge., Objective: To evaluate the different radiological diagnostic criteria for AOD and discuss potential treatment strategies based on a case with AOD and additional fracture of the atlas., Material and Methods: A 29-year-old male patient is presented who suffered from AOD with concomitant fracture of the anterior and posterior arches of the atlas with rotational atlantoaxial dislocation following an accident in forestry. The following parameters were evaluated for the diagnosis and assessment of postoperative reduction: Powers ratio, the X‑lines-method, Wackenheim line, basion-dens interval (BDI), basion-axial interval (BAI) and occipital condyle-C1 interval (CCI)., Results: Stabilization was performed by occipitocervical spondylodesis from C0 to C2/3. For final reduction it was necessary to reduce the malrotation of the atlas. In the presented case, the revised CCI proved to be a sensitive and valid yet practical parameter. Powers' ratio and the BDI were less suited for assessing the diagnosis. The X‑lines-method, Wackenheim line and the BAI did not adequately detect the pathological situation., Discussion: The AOD is a severe injury requiring immediate correct diagnosis for later adequate treatment results. Among the published parameters, the revised CCI proved to be a practical and valid parameter to detect AOD. For definitive treatment, the operative occipitocervical stabilization is regarded as the method of choice., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Concurrent craniocervical dissociation in a multi-trauma patient requiring venous-venous extracorporeal membranous oxygenation (ECMO) poses significant challenges in its management. Purpose: This article describes the nuances of the surgical decision-making in a complex case of a polytrauma patient with craniocervical dissociation who required concurrent ECMO. Study design/ setting: Case report and literature review Methods: The authors describe a complex case of a patient with craniocervical dissociation requiring ECMO and who was managed surgically in a level 1 trauma centre in Victoria, Australia after sudden neurological deterioration whilst in a halo-vest. A literature search using appropriate medical subject headings and keywords was performed to identify published cases of craniocervical dissociation in patients requiring concurrent ECMO. Results: Literature search yielded twenty-seven articles, with only two relevant articles identified for full text review. Only one article was found to be relevant, which however did not provide detailed discussion on surgical aspect of the pathology. Conclusion: To the authors' knowledge, this is the first report of management of craniocervical dissociation in a patient requiring ECMO due to polytrauma focused on the nuances of the complex surgical decision-making which is required for proper management of such critical condition.

• Retropharyngeal pseudomeningocele is a rare condition, which is usually detected weeks after trauma. • Early recognition and accurate diagnosis might help avoiding management delay and late intervention. • As surgical management is considered to be the definitive management, multidisciplinary management involving a team of Otolaryngology and Neurosurgery skull base surgeons is essential to achieve optimal outcomes. Retropharyngeal pseudomeningocele is a very rare form of pseudomeningocele, that is known to be associated with cervical trauma. Identifying such pathology can be challenging leading to delayed management. We report a case of post-traumatic retropharyngeal pseudomeningocele that was managed surgically in a 21-year-old gentleman with poly-trauma injuries due to a motor vehicle accident. After 10 weeks since the traumatic event, magnetic resonance imaging (MRI) and computerised tomography (CT) scan showed evidence of bilateral atlanto-occipital dislocation and a fluid collection of 8 × 4 × 2 cm in the retropharyngeal space. The patient was found to have dysphagia and muffled voice with difficult visualisation of the vocal cords upon examination. After a multidisciplinary team decision, the patient underwent cerebrospinal fluid (CSF) leak management, pseudomeningocele resection and dural defect repair with shunting conducted by the Neurosurgery and Otolaryngology. Postoperative assessments and patient's symptoms, at 9 months follow-up, were satisfactory and reassuring. It's believed that conservative management with bed rest, elevation of bed head and acetazolamide is the initial step in management. As an alternative measure, shunting of the CSF had led to resolution of the collection. However, surgical removal of the collection and direct dural defect repair have been suggested in the literature but needed to be properly studied. Early recognition of this condition is important to avoid management delay. With a multidisciplinary approach, surgical management can be safe and an acceptable option for retropharyngeal pseudomeningocele. [ABSTRACT FROM AUTHOR]

Background: Atlanto-occipital dislocation (AOD) is a rare, highly morbid, and highly lethal injury that results from high-energy trauma and almost universally requires operative management for satisfactory outcomes. It can be difficult to identify the severity of injury at the time of presentation, and when diagnosis is delayed outcomes worsen significantly. Anatomic anomalies of the craniovertebral junction may further complicate its detection. When such anomalies are present either singly or in combination, they are known to cause space constraints which may increase the likelihood of spinal cord injury. Given that such anomalies and AOD are rare, few examples of patients with both are reported in the literature. Furthermore, it is not clear in what way patient management may be impacted in this context. Case Description: We will present a unique case of an 18-year-old patient with traumatic AOD and an intact neurologic examination who was found to have atlanto-occipital assimilation (AOA), platybasia, basilar invagination, and severe Chiari I malformation, who was treated effectively with non-operative management. Conclusion: Our case demonstrates the successful application of a non-operative treatment strategy in a carefully selected patient with AOD in the context of AOA. [ABSTRACT FROM AUTHOR]

Objective: Atlanto-occipital dislocation is usually considered to be a fatal injury or one that leaves the victim with serious neurological deficits. The aim of this study is to illustrate a novel positive prognostic factor for atlanto-occipital dislocation, based on cervical MRI studies of patients who suffered this injury. Methods: Over the course of the past year, the authors have treated three consecutive patients with atlanto-occipital dislocation who attained an excellent clinical outcome. We retrospectively evaluated clinical, surgical and radiographic parameters in search of a common denominator to explain the excellent outcome of these patients. Results: All patients presented with severe polytrauma that required urgent surgical intervention including two laparotomies and a thoracotomy. The patients were subsequently treated with an occipitocervical fusion. No patient developed neurological deficits on long-term follow-up. The cervical MRI studies of all patients were notable for a having a preserved tectorial membrane, while other primary stabilizers of the craniocervical junction such as the apical, alar and cruciate ligaments were shown to be severely disrupted. We consider this anatomical distinction to account for their benign clinical course. Conclusion: A preserved tectorial membrane appears to be an important favorable prognostic factor in atlanto-occipital dislocation and may serve to mitigate neurological outcome in such injuries. To determine the integrity of the ligament and consequently affect clinical management, expeditious MRI of the cranio-cervical junction should be considered routinely in such injuries in addition to cervical CT scans. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective case analyses.Objective: The aim of this study was to investigate the incidence and characteristics of associated upper cervical spine injuries in 15 survival cases of traumatic atlanto-occipital dislocation (AOD).Summary Of Background Data: Traumatic AOD is a rare and generally fatal injury. Information regarding associated upper cervical spine injuries that may affect treatment methods, outcomes, and prognosis is limited.Methods: Fifteen patients (11 patients with posterior-type AOD and four patients with vertical-type AOD) who survived traumatic AOD were included in this study. Plain radiographs, computed tomography, magnetic resonance imaging, and medical records were reviewed. The incidence and characteristics of associated upper and lower cervical spine and thoracolumbar spine injuries and brain injuries were evaluated.Results: Thirteen patients with traumatic AOD (11 patients with posterior-type AOD and two patients with vertical-type AOD) showed associated upper cervical spine injuries; the overall incidence was 87% (100% in posterior-type AOD and 50% in vertical-type AOD). In posterior-type AOD, eight (72.7%) patients had C1 fractures (four patients had three-part fracture, three patients had two-part fracture, and one patient had four-part fracture), four (36.4%) patients had C1 lateral mass fractures, two (18.2%) patients had transverse atlantal ligament injuries. In vertical-type AOD, two (50%) patients had C1-C2 vertical subluxation with C1 anterior arch horizontal and sagittal split fractures. In posterior-type AOD, two (18%) patients had lower cervical spine injuries and one (9%) patient had brain injury. In vertical-type AOD, one (25%) patient had thoracic spine injury, and three (75%) patients had brain injuries additionally.Conclusion: Survival cases with traumatic AOD showed a high incidence of associated upper cervical spine injuries and brain injuries. High index of suspicion and careful radiologic examination are needed to investigate the presence of associated upper cervical spine injuries and brain injuries in traumatic AOD, which affects treatment, outcome, and prognosis.Level Of Evidence: 4. [ABSTRACT FROM AUTHOR]

Background: Airway management in patients with an unstable cervical spine requires a cautious approach if secondary damage is to be prevented but the question regarding the optimum method remains unresolved. The primary aim of the study was to investigate whether there were differences between intubation by conventional Macintosh laryngoscopy and placement of a laryngeal tube (LTS-D) with respect to dural sac compression on an unfixed human cadaver model with unstable injuries of the upper cervical spine. Secondary parameters that could be relevant in patients with unstable spinal injuries were also investigated.Material and Methods: Orotracheal intubation by conventional direct laryngoscopy using a Macintosh blade and placement of a laryngeal tube (LTS-D) were performed in six fresh human cadavers. The dural sac was filled with contrast dye to allow continuous myelography by lateral fluoroscopy. Changes in the width of the dural sac at the cervical segments (C) C0/C1 and the C1/C2 levels as well as secondary parameters (angulation, distraction, intervention time) were assessed in the intact spine as well as in the presence of combined atlanto-occipital dislocation and atlanto-axial instability. The intubation methods were considered independent and examined using the Mann-Whitney U‑test.Results: At the C0/C1 level in the intact spine, conventional laryngoscopy caused less reduction of the width of the dural sac than placement of the LTS-D (0.33 mm vs. 0.46 mm, p = 0.035); however, in the presence of combined atlanto-occipital dislocation and atlanto-axial instability, placement of the LTS-D caused less reduction in the width of the dural sac than conventional intubation (1.18 mm vs. 0.68 mm, p = 0.005). At the C1/C2 level no differences were found with respect to changes in the width of the dural sac, neither in the intact spine nor in combined atlanto-occipital dislocation and atlanto-axial instability. Conventional intubation caused more angulation than placement of the LTS-D at both levels measured. Both methods did not cause distraction. The intervention times for placement of the laryngeal tube were shorter.Conclusion: In an unfixed human cadaver model with combined atlanto-occipital dislocation and atlanto-axial instability, placement of the LTS-D caused less reduction in the width of the dural sac than conventional intubation at the level of the craniocervical junction. The LTS-D also caused less angulation and could be placed faster. It could therefore also be advantageous over conventional intubation in living patients with an unstable cervical spine. [ABSTRACT FROM AUTHOR]

Proatlas segmentation anomalies represent a rare subset of congenital craniovertebral junction anomalies. In this condition, the structures originating from the proatlas, such as the clivus, occipital condyles, foramen magnum rim, and odontoid tip, may demonstrate congenital anomalies, usually without any spinal instability. Elongated clivus, as a result of nonsegmentation of the odontoid tip from the rest of the proatlas, has been reported before to cause ventral spinal cord compression. We report such a case with certain unreported other associations and explore the pathoembryology and management options of such complex anomalies. An 8-year old girl presented with a 2-year history of progressive spastic quadriparesis. On neuroimaging, the anterior arch of the atlas was deficient, the odontoid process was foreshortened, and the clivus was elongated, encroaching into the spinal canal leading to ventral spinal cord compression. Additionally, there was rotatory posterior dislocation of the occipital condyles onto the posterior atlantal arch and vertebral artery anomaly. This patient underwent transoral decompression followed by occipitocervical fusion using rods and screws with satisfactory results. Proatlas anomalies are rare, varied, and often subtle enough to go unrecognized. Knowledge of the embryology and its aberrations is necessary to understand these anomalies. Our case describes a rare form of bony anomalies pertaining to the fate of the proatlas with accompanying atlanto-occipital dislocation. [ABSTRACT FROM AUTHOR]

Although instrumented stabilization of pediatric atlanto-occipital dislocation (AOD) has been described in the literature, there is little evidence regarding instrumentation techniques in pediatric patients presenting with both AOD and a cervical fracture. We present a case of a 2-year-old male involved in a motor vehicle collision with an unstable C2 fracture and AOD, treated with an occiput-C4 posterior arthrodesis using a rod, crosslink, and cable construct. This patient suffered a type III C2 fracture and AOD with 4 mm craniocaudal and 3 mm anterior displacement. In the operating room, 2 cobalt chrome connecting rods (3.5 mm) were connected to 1 another with crosslinks at C2 and C4. These were affixed with suboccipital and sublaminar cables at C1, C2, and C4. At 14 months postoperatively, his spine is clinically and radiographically stable. He has spontaneous movement in all 4 extremities, and remains in a persistent vegetative state because of his underlying central nervous system injury. Although there is a breadth of literature investigating instrumentation approaches to pediatric AOD, there is minimal evidence on outcomes of patients presenting with both AOD and cervical fracture. The technique we describe has proven safe and effective for this patient. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the compression of the dural sac and the cervical spinal movement during performing different airway interventions in case of atlanto-occipital dislocation.Methods: In six fresh cadavers, atlanto-occipital dislocation was performed by distracting the opened atlanto-occipital joint capsule and sectioning the tectorial membrane. Airway management was done using three airway devices (direct laryngoscopy, video laryngoscopy, and insertion of a laryngeal tube). The change of dural sac’s width and intervertebral angulation in stable and unstable atlanto-occipital conditions were recorded by video fluoroscopy with myelography. Three-dimensional overall movement of cervical spine was measured in a wireless human motion track system.Results: Compared with a mean dural sac compression of − 0.5 mm (− 0.7 to − 0.3 mm) in stable condition, direct laryngoscopy caused an increased dural sac compression of − 1.6 mm (− 1.9 to − 0.6 mm, p = 0.028) in the unstable atlanto-occipital condition. No increased compression on dural sac was found using video laryngoscopy or the laryngeal tube. Moreover, direct laryngoscopy caused greater overall extension and rotation of cervical spine than laryngeal tube insertion in both stable and unstable conditions. Among three procedures, the insertion of a laryngeal tube took the shortest time.Conclusion: In case of atlanto-occipital dislocation, intubation using direct laryngoscopy exacerbates dural sac compression and may cause damage to the spinal cord. [ABSTRACT FROM AUTHOR]

The objective of this study is to describe a series of cranio-cervical dissociation victims and evaluate their outcomes as well as discuss the clinical dilemmas we faced in the context of current literature evidence. This is a retrospective cohort study of traumatic occipito-cervical dissociation in five patients (three males and two females) encountered between 2010 and 2016 at a tertiary care facility in the Middle East region. All patients underwent occipito-cervical fusion using screws and rods system with mean postoperative follow-up period of 2.5 years. All patients survived, and four were independently mobile and one wheel chair bound. Most had some degree of neurological sequelae, often due to associated injuries and all complained of limited neck range of motion. Contemporary literature review shows that CT scan with MRI is often the best diagnostic modality. Surgery is usually indicated though rare cases treated conservatively have been reported. The commonest predictor of mortality is missed injury, associated head injury and wide separation between the skull base and C1 on imaging studies. [ABSTRACT FROM AUTHOR]

Background Atlanto-occipital dislocation (AOD) is the most uncommon form of traumatic cervical spine injury. The majority of patients die before reaching higher-level care, and only a small percentage of patients with AOD survive the initial injury after receiving tertiary care. As such, there is a paucity of evidence-based management guidelines for treating this condition. Halo vest fixation has been a proposed method for interim stability while these patients undergo medical optimization for surgical intervention. There have been several reports of worsening AOD after halo placement. Reverse Trendelenburg position after halo fixation has been previously described to aid in the reduction of AOD, as well as concomitant atlantoaxial dislocation by gravitational downward force. Case Description In this series we present 2 cases of obese patients (body mass index >30) with AOD treated by halo fixation that had increased distraction after head of bed elevation. Conclusion Our theorized mechanism for this phenomenon is due to the downward pull of subaxial forces secondary to a large body habitus. [ABSTRACT FROM AUTHOR]

Background Atlanto-occipital rotatory dislocation (AORD) has rarely been reported in the literature; for this reason, the clinicoradiologic characteristics of this injury are not well described. Methods We describe the case of a 67-year-old man who sustained a cervical spine trauma. He reported only neck pain and was neurologically intact. A computed tomography scan showed a rotatory displacement of the atlanto-occipital joints associated with a widened condylar–C1 interval; in addition, magnetic resonance imaging showed injuries to the stabilizing ligaments of this area. A systematic literature review was also performed to identify previous cases of patients with AORD. Results The patient was treated with craniocervical fixation from occipital to C1, achieving a good outcome. The literature review yielded 9 cases of patients with AORD. Compared with patients with atlanto-occipital dislocation, patients with rotatory dislocations have a less severe degree of displacement of the atlanto-occipital joints and better clinical outcome. Conclusions Compared with previously classified atlanto-occipital dislocations, AORD is an independent and unique variation. AORD presents with different biomechanical, clinicoradiologic, and prognostic characteristics and represents an important addition to the spectrum of atlanto-occipital dislocation injuries. [ABSTRACT FROM AUTHOR]

Atlanto-occipital dislocation (AOD) is an injury with high morbidity and mortality. We present a case of survival of a pediatric patient with the diagnoses of AOD, retroclival hematoma, and resulting hydrocephalus. The patient's cervical spine was stabilized until occipital-cervical fusion provided definitive treatment, and the hydrocephalus was treated with a ventriculostomy. The patient survived with no neurological deficits. A better understanding and awareness of the radiologic criteria of AOD will lead to earlier recognition of AOD and improved outcomes, even in the presence of complications from AOD. Surgical fixation should be used for definitive treatment of injuries with AOD.

Background Nontraumatic spontaneous atlanto-occipital dislocation (AOD) is rare. In this report, we discuss the technical steps of condylar joint fusion and stabilization (by screws and plates) in nontraumatic AOD. To the best of our knowledge, it is the first report of such techniques. Material and Methods A young girl and a young man with progressive quadriparesis due to nontraumatic spontaneous atlanto-occipital dislocation were managed by microsurgical reduction, fusion, and stabilization of the joint by occipital condylar and C1 lateral mass screw and plate fixation after mobilization of vertebral artery. Result In both cases, condylar joints fixation and fusion were done successfully. Conclusion Condylar joint stabilization and fusion may be a good or alternative option for AOD. [ABSTRACT FROM AUTHOR]

Background: Atlanto-occipital dislocation (AOD) is a rare but severe sequela of high energy trauma. Children are at increased risk, due to their immature spine and biomechanical characteristics. Literature review: The prevailing mechanism of injury is motor vehicle collision as passenger. AOD commonly presents with cardiorespiratory arrest, spinal cord injury or cranial nerve deficits. Concomitant injuries, such as traumatic brain injury, are frequently encountered. Diagnosis is made on CT and MRI imaging. Posterior internal fixation is the recommended treatment. Thirty-four percent of patients die, 41 % survive with deficits and 25 % have a complete neurological recovery. Initial symptoms, GCS score and degree of spinal cord injury appear to be predictors of outcome. Illustrative case: We report the case of a 9-year-old boy, who presented in extremis with cardiac arrest after a motor vehicle collision. Upon successful resuscitation, diagnostic imaging showed AOD and a Chiari I malformation. An occiput-C2 posterior instrumented fusion was performed. The patient subsequently received intensive rehabilitation and recovered to independent ambulation, with a persistent, asymptomatic Chiari I malformation. Conclusion: This case highlights the potential for positive outcome in paediatric AOD, despite the presence of strong predictors of poor or fatal outcome at presentation. [ABSTRACT FROM AUTHOR]

Traumatic atlanto-occipital dislocation (AOD) is an ominous injury with high mortality and morbidity in trauma patients. Improved survival has been observed with advancements in pre-hospital and hospital care. Furthermore, high quality imaging studies are accessible at most trauma centers; these are crucial for prompt diagnosis of AOD. The objective of this study is to perform a comprehensive literature review of traumatic AOD, with specific emphasis on identifying prognostic factors for survival. A review of the literature was performed using the Medline database for all traumatic atlanto-occipital articles published between March 1959 and June 2015; 141 patients from 60 total studies met eligibility criteria for study inclusion. A binary logistic regression model was utilized to identify prognostic factors. The analysis assessed age, sex, spinal cord injury (SCI), traumatic brain injury (TBI), polytrauma injury (PI), and Traynelis AOD Classification. Only TBI was statistically significantly associated with death (OR 8.05 p < 0.05); SCI did not reach statistical significance for predicting mortality in AOD patients (OR 1.25 p > 0.05). Age, sex, PI, and Traynelis AOD Classification did not meet significance to predict mortality in AOD patients. We found that patients with TBI are eight times more likely to die than patients without TBI. A high degree of suspicion for AOD during pre-hospital care, as well as, prompt diagnosis and management in the trauma center play a key role in the treatment of this devastating injury. The relationship between survival and factors such as TBI and SCI should be further explored. [ABSTRACT FROM AUTHOR]

Traumatic occipitocervical dissociation (OCD) results from ligamentous injury to the craniocervical junction and is associated with a high rate of mortality and significant neurologic morbidity. The diagnosis is frequently missed on initial lateral cervical spinal radiographs mainly due to inadequate visualization of radiological landmarks and low degree of suspicion. Widespread availability of multidetector computed tomography (MDCT) of the spine and development of better diagnostic radiological criteria has allowed timely diagnosis and good clinical outcome following posterior occipitocervical fusion and instrumentation for a pathology that was once considered uniformly fatal. The present paper reviews the clinical features, diagnosis, and management of OCD in light of most recent literature. [ABSTRACT FROM AUTHOR]

Atlanto-occipital dislocation with fracture (AODF) of adjoining bone is rarely reported and poses diagnostic challenge due to complex anatomy and inability of plain radiograph to diagnose it. Authors present two cases of AODF with fracture of adjoining bone with delayed presentations, including one patient with occipitalized C1. Clinical and radiological findings, causes of diagnostic delays, and surgical management are described along with a review of relevant literature. [ABSTRACT FROM AUTHOR]

The aim of this work was to present a novel minimally invasive surgical stabilization technique for canine atlanto-occipital dislocation and to report the associated magnetic resonance imaging (MRI) findings. All 5 dogs in this case series underwent 1.5 T MRI of the head and neck and 3 underwent both MRI and computed tomography (CT). Atlanto-occipital dislocations were diagnosed based on the increased joint space between the occipital condyles and the atlas on MRI. Surgery was performed immediately with a never previously described fixation technique based on an external ligature. The stabilization was performed via 4 holes drilled in the zygomatic processes and in the atlas wings on each side. A nylon monofilament of 1 mm diameter was inserted in the 4 holes, and an O-shaped ligature was carried out externally to the skin through the ipsilateral zygomatic arch. Ligatures were removed within 2 months. At the postsurgical follow-up examination, 14 days after surgery, all dogs were found to be ambulatory. Atlanto-occipital stability was assessed by clinical examination with an average of 24 months of follow-up. The positive outcomes in this case series suggest that atlanto-occipital dislocation may be surgically treated with this novel technique, irrespective of the severity of the clinical presentation and associated lesions observed on MRI. [ABSTRACT FROM AUTHOR]

Background: Traumatic atlanto-occipital dislocation (AOD) is a rare but often fatal injury. Consequently, long-term data regarding surviving patients have been limited. In particular, the occurrence of hydrocephalus is not well-documented. Case Description: A 33-year-old male sustained AOD as a consequence of a motor vehicle collision. Although he did well initially after an occipitocervical fusion, 1 month after his operation, he exhibited signs of increased intracranial pressure (bilateral abducens nerve palsies, worsening headaches, and fatigue). He was found to have hydrocephalus, which was responsive to shunting. Conclusion: Manifestations of hydrocephalus after AOD can be variable, ranging from interval ventricular dilatation to pseudomeningoceles and syringomyelia. In addition, the timing of presentation can be acute, requiring emergent external ventricular drainage, or delayed, requiring ongoing vigilance. Consequently, as more patients survive this once thought to be fatal injury, caution for hydrocephalus is stressed. [ABSTRACT FROM AUTHOR]