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The Journal of the American Academy of... Feb 2020Os odontoideum is a rare entity of the second cervical vertebra, characterized by a circumferentially corticated ossicle separated from the body of C2. The ossicle is a... (Review)
Review
Os odontoideum is a rare entity of the second cervical vertebra, characterized by a circumferentially corticated ossicle separated from the body of C2. The ossicle is a distinct entity from an odontoid fracture or a persistent ossiculum terminale. The diagnosis may be made incidentally on imaging obtained for the workup of neck pain or neurologic signs and symptoms. Diagnosis usually can be made with plain radiographs. MRI and CT can assess spinal cord integrity and C1-C2 instability. The etiology of os odontoideum is a topic of debate, with investigative studies supporting both congenital and traumatic origins. A wide clinical range of symptoms exists. Symptoms may present as nondescript pain or include occipital-cervical pain, myelopathy, or vertebrobasilar ischemia. Asymptomatic cases without evidence of radiologic instability are typically managed with periodic observation and serial imaging. The presence of atlantoaxial instability or neurological dysfunction necessitates surgical intervention with instrumentation and fusion for stability.
Topics: Axis, Cervical Vertebra; Child; Humans; Joint Instability; Spinal Fusion
PubMed: 31977608
DOI: 10.5435/JAAOS-D-18-00637 -
Ugeskrift For Laeger Feb 2020This review summarises the present, limited, knowledge of os odontoideum (OO). The prevalence is unknown, and the aetiology is widely debated, though irrelevant to... (Review)
Review
This review summarises the present, limited, knowledge of os odontoideum (OO). The prevalence is unknown, and the aetiology is widely debated, though irrelevant to management of the disease. Surgery of symptomatic patients is advocated, as there is more uncertainty about the treatment of asymptomatic patients. Diagnosis is obtained with plain X-ray. However, nowadays MRI and CT scanning are recommended for further clarification and judgement of the severity. Knowledge of OO is important to minimise misjudgement and consequently inappropriate treatment. It is recommended, that patients are examined by highly specialised spine doctors before further cervical manipulation due to the high risk of instability with potentially severe consequences.
Topics: Axis, Cervical Vertebra; Humans; Magnetic Resonance Imaging; Odontoid Process; Quadriplegia; Tomography, X-Ray Computed
PubMed: 32138818
DOI: No ID Found -
Surgical and Radiologic Anatomy : SRA Feb 2020To elucidate the imaging manifestations of os odontoideum, establish the diagnosis and guide surgical therapy.
OBJECTIVE
To elucidate the imaging manifestations of os odontoideum, establish the diagnosis and guide surgical therapy.
METHODS
Clinical and imaging data, including X-ray, CT and MR of 24 patients with os odontoideum, were retrieved and reviewed retrospectively.
RESULTS
Os odontoideum with intact cortex was divided into round, conical and blunt tooth types. Four cases of orthotopic and 20 cases of dystopic os odontoideum were included. There was anterior displacement of the base of the dens in six cases, posterior displacement in nine cases and no displacement in nine cases. A widening of anterior atlanto-axial space was shown in 14 patients with varying degrees. Thickening of the soft tissue posterior to the dens was observed in 19 patients, spinal canal stenosis in 21 patients, cervical myelopathy in 10 patients and craniocervical junction malformation in 9 patients. Posterior C1-C2 pedicle screw fixation and fusion was performed in 12 patients and 4 patients underwent posterior occipito-cervical fixation and fusion.
CONCLUSION
Radiographically, os odontoideum is defined as an independent ossicle of variable size with smooth circumferential cortical margins separated from the axis. Imaging can be used to assess atlanto-axial instability, associated normal or abnormal anatomical structures and guide surgical therapy.
Topics: Adult; Aged; Atlanto-Axial Joint; Axis, Cervical Vertebra; Female; Humans; Joint Instability; Magnetic Resonance Imaging; Male; Middle Aged; Pedicle Screws; Retrospective Studies; Spinal Fusion; Tomography, X-Ray Computed
PubMed: 31616983
DOI: 10.1007/s00276-019-02351-3 -
The Journal of Bone and Joint Surgery.... Apr 1980A review of the cases of thirty-five patients with os odontoideum, the largest series reported to date, supports the concept that trauma is the etiology of the...
A review of the cases of thirty-five patients with os odontoideum, the largest series reported to date, supports the concept that trauma is the etiology of the abnormality. Most of the patients had roentgenographic instability of the affected spinal segment, and were treated with spine fusion. Eleven patients had lesions attributable to injuries received before they were four years old, although surgical treatment usually was delayed for one to eight years. Nine patients had documented roentgenographic evidence of a normal odontoid process prior to the development of the os odontoideum. Only one-third of the patients had any signs or symptoms indicative of neural deficits, although most patients had cervical pain. Surgical treatment alleviated the pain and instability.
Topics: Adolescent; Adult; Age Factors; Aged; Axis, Cervical Vertebra; Child; Child, Preschool; Female; Humans; Joint Diseases; Male; Middle Aged; Radiography; Spinal Fusion; Spinal Injuries; Time Factors
PubMed: 7364809
DOI: No ID Found -
European Spine Journal : Official... Mar 2024Os odontoideum refers to a rounded ossicle detached from a hypoplastic odontoid process at the body of the axis. The aetiology has been debated and believed to be either... (Review)
Review
INTRODUCTION
Os odontoideum refers to a rounded ossicle detached from a hypoplastic odontoid process at the body of the axis. The aetiology has been debated and believed to be either congenital or acquired (resulting from trauma). Os odontoideum results in incompetence of the transverse ligament and thus predisposes to atlantoaxial instability and spinal cord injury.
METHODS/RESULTS
Three cases of children with severe dystonic cerebral palsy presenting with myelopathic deterioration secondary to atlantoaxial instability due to os odontoideum are presented. This observation supports the hypothesis of os odontoideum being an acquired phenomenon, secondary to chronic excessive movement with damage to the developing odontoid process.
CONCLUSION
In children with cerebral palsy and dystonia, pre-existing motor deficits may conceal an evolving myelopathy and result in delayed diagnosis of clinically significant atlantoaxial subluxation.
Topics: Child; Humans; Dystonia; Cerebral Palsy; Magnetic Resonance Imaging; Atlanto-Axial Joint; Axis, Cervical Vertebra; Spinal Cord Diseases; Odontoid Process; Joint Instability
PubMed: 37994987
DOI: 10.1007/s00586-023-08044-1 -
World Neurosurgery Feb 2020The aim of this study was to report an experience with 190 cases of os odontoideum over 20 years. The management outcome following atlantoaxial fixation was analyzed.
OBJECTIVE
The aim of this study was to report an experience with 190 cases of os odontoideum over 20 years. The management outcome following atlantoaxial fixation was analyzed.
METHODS
From January 2000 to September 2018, 190 patients with os odontoideum were surgically treated. There were 113 male patients and 77 female patients; average age was 24 years (range, 2-68 years).The patients were divided into 3 groups depending on the nature of atlantoaxial dislocation (group 1, mobile and partially or completely reducible atlantoaxial dislocation; group 2, fixed or irreducible atlantoaxial dislocation; group 3, presence of basilar invagination). There were 65 pediatric patients (<18 years old). All patients underwent atlantoaxial joint manipulation and lateral mass plate and screw fixation. The goal of surgery was segmental atlantoaxial arthrodesis. No transoral or posterior foramen magnum bone decompression was done. Occipital bone was not included in the fixation construct.
RESULTS
On direct bone handling and observation, atlantoaxial joint pathologic hyperactivity related instability was identified in all patients. Atlantoaxial segmental stabilization resulted in clinical symptomatic and neurologic improvement in 100% of patients.
CONCLUSIONS
Os odontoideum signifies chronic or long-standing atlantoaxial instability. Segmental atlantoaxial fixation is a reliable form of surgical treatment. Bone decompression is not necessary. Inclusion of occipital bone and subaxial vertebrae in the fixation construct is not necessary.
Topics: Adolescent; Adult; Aged; Atlanto-Axial Joint; Axis, Cervical Vertebra; Child; Child, Preschool; Female; Humans; Joint Instability; Male; Middle Aged; Spinal Fusion; Treatment Outcome; Young Adult
PubMed: 31669688
DOI: 10.1016/j.wneu.2019.10.107 -
Orthopaedic Review Dec 1987
Review
Topics: Axis, Cervical Vertebra; Humans; Odontoid Process; Radiography; Spinal Diseases
PubMed: 3333595
DOI: No ID Found -
Child's Nervous System : ChNS :... Apr 2023There are two separate theories regarding the genesis of os odontoideum: congenital and post-traumatic. Trauma documentation in the past has been the presence of a... (Review)
Review
OBJECTIVE
There are two separate theories regarding the genesis of os odontoideum: congenital and post-traumatic. Trauma documentation in the past has been the presence of a normal odontoid process at the time of initial childhood injury and subsequent development of the os odontoideum. True MR documentation of craniocervical injury in early childhood and subsequent os odontoideum formation has been very rare.
METHODS
An 18-month-old sustained craniocervical ligamentous injury documented on MRI with transient neurological deficit. Chiari I abnormality was also recorded. Subsequent serial imaging of craniocervical region showed the formation of os odontoideum and instability. He became symptomatic from the os odontoideum and the Chiari I abnormality. The patient underwent decompression and intradural procedure for Chiari I abnormality and occipitocervical fusion. Postoperative course was complicated by the failure of fusion and redo. He later required transoral ventral medullary decompression. He recovered.
RESULTS
This is an MR documented craniocervical ligamentous injury with sequential formation of os odontoideum with accompanying changes in the atlas. Despite a subsequent successful dorsal occipitocervical fusion, he became symptomatic requiring transoral decompression.
CONCLUSIONS
Os odontoideum here is recognized as a traumatic origin with the presence of congenital Chiari I abnormality as a separate entity. The changes of the anterior arch of C1 as well as the os formation were serially documented and give credence to blood supply changes in the os and atlas as a result of the trauma. The recognized treatment of dorsal occipitocervical fusion failed in this case requiring also a ventral decompression of the medulla.
Topics: Male; Humans; Child, Preschool; Infant; Odontoid Process; Axis, Cervical Vertebra; Magnetic Resonance Imaging; Trauma, Nervous System; Spinal Fusion; Atlanto-Axial Joint
PubMed: 36828956
DOI: 10.1007/s00381-023-05892-6 -
The Journal of Bone and Joint Surgery.... Oct 2019Treatment outcomes and risk factors for neurological deficits in pediatric patients with an os odontoideum are unclear.
BACKGROUND
Treatment outcomes and risk factors for neurological deficits in pediatric patients with an os odontoideum are unclear.
METHODS
We reviewed the data for 102 children with os odontoideum who were managed at 11 centers between 2000 and 2016 and had a minimum duration of follow-up of 2 years. Thirty-one children had nonoperative treatment, and 71 underwent instrumented posterior cervical spinal arthrodesis for the treatment of C1-C2 instability. Nonoperative treatment consisted of observation (n = 29) or immobilization with a cervical collar (n = 1) or halo body jacket (n = 1). Surgical treatment consisted of atlantoaxial (n = 50) or occipitocervical (n = 21) arthrodesis. One patient also underwent transoral odontoidectomy.
RESULTS
Thirty children (29%) presented with neurological deficits, 28 of whom had radiographic atlantoaxial instability (atlantoaxial distance >5 mm) or limited space (≤13 mm) available for the spinal cord (risk ratio, 7.8 [95% confidence interval, 2.0 to 31] compared with children with no radiographic risk factors). The 27 children without neurological deficits or atlantoaxial instability at presentation underwent nonoperative treatment and remained asymptomatic. Of the initial nonoperative cohort, one child developed atlantoaxial instability, and another had a persistent neurological deficit; both children underwent spinal arthrodesis during the study period. One child with cervical instability declined surgery and remained asymptomatic. Spinal fusion occurred in 68 patients in the surgical group by the end of the study period (mean, 3.7 years; range, 2.0 to 11.8 years). Surgical complications occurred in 21 children, including nonunion in 12, new neurological deficits in 4, cerebrospinal fluid leak in 2, symptomatic instrumentation requiring removal 2, and vertebral artery injury in 1. Nine children underwent revision surgery. In the surgical group, Japanese Orthopaedic Association neurological function scores improved significantly from preoperatively to the latest follow-up for the upper extremities (p = 0.026) and lower extremities (p = 0.007).
CONCLUSIONS
The risk of developing a neurological deficit was strongly associated with atlantoaxial instability and limited space available for the spinal cord in children with os odontoideum. Nonoperative treatment was safe for asymptomatic patients without atlantoaxial instability. Spinal arthrodesis resolved the neurological deficits of children with symptomatic os odontoideum.
LEVEL OF EVIDENCE
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Topics: Adolescent; Atlanto-Axial Joint; Axis, Cervical Vertebra; Braces; Child; Child, Preschool; Humans; Immobilization; Infant; Joint Instability; Neck Pain; Nervous System Diseases; Risk Factors; Spinal Cord Injuries; Spinal Fusion; Treatment Outcome; Watchful Waiting
PubMed: 31577680
DOI: 10.2106/JBJS.19.00314 -
Neurosurgical Focus Dec 2011Os odontoideum was first described in the late 1880s and still remains a mystery in many respects. The genesis of os odontoideum is thought to be prior bone injury to... (Review)
Review
Os odontoideum was first described in the late 1880s and still remains a mystery in many respects. The genesis of os odontoideum is thought to be prior bone injury to the odontoid, but a developmental cause probably also exists. The spectrum of presentation is striking and ranges from patients who are asymptomatic or have only neck pain to those with acute quadriplegia, chronic myelopathy, or even sudden death. By definition, the presence of an os odontoideum renders the C1-2 region unstable, even under physiological loads in some patients. The consequences of this instability are exemplified by numerous cases in the literature in which a patient with os odontoideum has suffered a spinal cord injury after minor trauma. Although there is little debate that patients with os odontoideum and clinical or radiographic evidence of neurological injury or spinal cord compression should undergo surgery, the dispute continues regarding the care of asymptomatic patients whose os odontoideum is discovered incidentally. The authors' clinical experience leads them to believe that certain subgroups of asymptomatic patients should be strongly considered for surgery. These subgroups include those who are young, have anatomy favorable for surgical intervention, and show evidence of instability on flexion-extension cervical spine x-rays. This recommendation is bolstered by the fact that surgical fusion of the C1-2 region has evolved greatly and can now be done with considerable safety and success. When atlantoaxial instrumentation is used, fusion rates for os odontoideum should approach 100%.
Topics: Adolescent; Disease Management; Female; Humans; Incidental Findings; Odontoid Process; Spinal Fusion
PubMed: 22133185
DOI: 10.3171/2011.9.FOCUS11227