- Pars Advanced and Minimally Invasive Medical Manners Research Center, Pars Hospital, Iran University of Medical Sciences, Tehran, Iran.
DOI:10.25259/SNI-308-2019Copyright: © 2019 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Abolfazl Rahimizadeh, Zahed Malekmohammadi, Mona Karimi, Ava Rahimizadeh, Naser Asgari. Unstable os odontoideum contributing to cervical myelopathy and obstructive sleep apnea. 28-Jun-2019;10:125
How to cite this URL: Abolfazl Rahimizadeh, Zahed Malekmohammadi, Mona Karimi, Ava Rahimizadeh, Naser Asgari. Unstable os odontoideum contributing to cervical myelopathy and obstructive sleep apnea. 28-Jun-2019;10:125. Available from: http://surgicalneurologyint.com/surgicalint-articles/9437/
Background: Sleep apnea is characterized by repetitive cessation of breathing during sleep. It may be attributed to obstructive, central, or mixed pathologies close to the upper airway resulting in a decreased diameter of the oropharyngeal tract.
Case Description: A 36-year-old male with progressive cervicomedullary myelopathy/quadriparesis exhibited obstructive sleep apnea (OSA) attributed to an anteriorly displaced os odontoideum (OO). Atlantoaxial screw-rod stabilization resulted in improvement of both neurological function and OSA.
Conclusion: A symptomatic unstable OO may contribute to suboccipital pain, progressive quadriparesis, vertebrobasilar insufficiency, and OSA. Appropriate operative intervention utilizing atlantoaxial screw-rod stabilization may help to resolve these deficits.
Keywords: Cervical myelopathy, Obstructive sleep apnea, OS odontoideum
Obstructive sleep apnea (OSA) is defined by momentary, cyclical cessation in breathing that is not severe enough to cause significant arterial hypoxemia and/or hypercapnia.[
Os odontoideum (OO), a traumatic or congenital abnormality of the second cervical vertebrae, is characterized by a separate bony segment with a smooth circumferential margin.[
A 36-year-old male exhibited a progressive spastic quadriparesis (hyperactive reflexes, positive Hoffmann signs, and an equivocal plantar reflex bilaterally) of 6-month duration. He also had developed OSA over the past 2 years, documented by two overnight polysomnography studies.
Radiographic confirmation of OO
The dynamic lateral cervical X-rays showed a free-floating OO that compromised the oropharyngeal airway [
The cervical magnetic resonance imaging (MRI) showed atlantoaxial dislocation attributed to anterior displacement of the OO resulting in marked AP diameter canal narrowing at the cervicomedullary junction [
(a) T1-weighted sagittal magnetic resonance imaging (MRI) of cervical spine shows an os odontoideum (OO) with atlantoaxial dislocation and narrowing of the cervicomedullary junction. The OO and atlas ring are engulfed in a soft tissue extending from os to axis. The posterior airway space is quite narrow in the MRI taken in neuter position (white dash). (b) T2-weighted sagittal MRI shows myelopathy at the cervicomedullary junction.
Computed tomography (CT) studies (coronal and sagittal images) also confirmed anterior displacement of the OO. The sagittal CT showed the characteristic jigsaw pattern [
Computed tomography scan of the cervical spine, (a) axial view shows atlantoaxial dislocation. (b) Reconstructed sagittal view shows displaced os odontoideum (OO) - atlas ring forward displacement in jigsaw pattern; note posterior airway space is very narrow with the neck in neuter position. (c) Reconstructed coronal view shows the OO.
The patient underwent a C1-C2 posterior fusion [
Frequency and etiology of OSA and rarity with OO
OSA is a relatively common but highly morbid condition that affects middle-aged adults (e.g., 9.1% of males and 4% of females).[
Surgery for OO
The surgical management of unstable OO requires C1-C2 reduction and fusion/fixation best achieved with the classic Harms technique.[
A symptomatic os odontoideum may contribute to suboccipital pain, progressive quadriparesis, vertebrobasilar insufficiency, and OSA. Appropriate operative intervention may help resolve these deficits.
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
There are no conflicts of interest.
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