Elsevier

Surgical Neurology

Volume 53, Issue 2, February 2000, Pages 106-109
Surgical Neurology

Spine
Os odontoideum: etiology, diagnosis, and management

https://doi.org/10.1016/S0090-3019(99)00184-6Get rights and content

Abstract

BACKGROUND

There have been few reports of os odontoideum since the initial description.

METHODS

Forty-four patients with os odontoideum treated during the period 1980 through 1996 were reviewed. There were 33 males and 11 females. Their ages ranged from 7 to 56 years, with an average of 24.6 years. Five patients with no symptoms were treated conservatively. Thirty-nine patients underwent operative treatment including nine posterior atlantoaxial fusions and 33 occipitocervical fusions.

RESULTS

The patients were followed up for one to 16 years, with an average of 6.5 years. Five patients treated conservatively have remained stable. All 39 treated patients achieved solid arthrodesis. The results were satisfactory.

CONCLUSIONS

We conclude that fusion is indicated if atlantoaxial instability or clinical symptoms are significant, and that occipitocervical fusion should be considered in the operative management of os odontoideum if atlantoaxial arthrodesis is impossible.

Section snippets

Patients and methods

Between 1980 and 1996, 44 patients with os odontoideum were treated at Changzheng Hospital, Shanghai. There were 33 males and 11 females. Their ages ranged from 7 to 56 years with an average of 24.6 years. The time from onset of symptoms to admission was 2 hours to 14 years with an average of 2 years and 8 months.

Eighteen patients had a definite history of injury to the neck, but in 13 patients only an episode of mild cervical trauma was reported, and the mechanism of injury could not be

Results

The five patients who received conservative management have remained stable. The remaining 39 patients achieved solid arthrodesis postoperatively. Of these, symptoms and signs disappeared in 26, and significantly decreased in severity in 13.

Discussion

The etiology of os odontoideum remains unsettled; both acquired and congenital mechanisms have been suggested. In this series, most patients had no history of cervical trauma. Other congenital occipitocervical deformities have been associated with os odontoideum [14]. On imaging studies, a combination of hypoplasia of the posterior arch with hyperplasia of the anterior arch in the atlas is sometimes identified [5]. Os odontoideum has been noted to have a round or oval shape and a smooth margin.

References (21)

  • M.M.H. Teng et al.

    CT and myelogram findings of os odontoideum

    Comput Med Imaging Graph

    (1989)
  • E.G. Dawson et al.

    Atlanto-axial subluxation in children due to vertebral anomalies

    J Bone Joint Surg [Am]

    (1979)
  • T.B. Ducker

    Os odontoideum

    J Spinal Disord

    (1993)
  • J.W. Fielding et al.

    Os odontoideum

    J Bone Joint Surg [Am]

    (1980)
  • A.D. Greenberg

    Atlanto-axial dislocations

    Brain

    (1968)
  • R.G. Holt et al.

    Hypertrophy of C-1 anterior archuseful sign to distinguish os odontoideum from acute dens fracture

    Radiology

    (1989)
  • S. Hukuda et al.

    Traumatic atlantoaxial dislocation causing os odontoideum in infants

    Spine

    (1980)
  • K.A. Kirlew et al.

    Os odontoideum in identical twinsperspectives on etiology

    Skeletal Radiol

    (1993)
  • S.E. Koop et al.

    The surgical treatment of instability of the upper part of the cervical spine in children and adolescents

    J Bone Joint Surg [Am]

    (1984)
  • P. Marcotte et al.

    Posterior atlantoaxial facet screw fixation

    J Neurosurg

    (1993)
There are more references available in the full text version of this article.

Cited by (90)

  • Post-traumatic os odontoideum - case presentation and literature review

    2018, Trauma Case Reports
    Citation Excerpt :

    Most patients will present in childhood with neck pain or neurologic symptoms due to cord compression from posterior translation of the Os into the cord in extension or the odontoid into the cord in flexion. Increased motion at the C-1 to C-2 level can lead to vertebral artery occlusion, ischemia of the brainstem and posterior fossa structures, resulting in seizures, syncope, vertigo, visual disturbances and even sudden death [15–26]. C1–C2 instability without a fracture is highly uncommon in adults.

  • The Role of Conservative Management in Incidental Os Odontoideum

    2016, World Neurosurgery
    Citation Excerpt :

    In asymptomatic patients with evidence of radiographic instability, the 2 management approaches consist of a conservative approach with clinical and radiologic surveillance or, alternatively, operative stabilization involving fusion. Conflicting recommendations exist within the literature, with some studies proposing conservative management in specific subgroups based on findings of no adverse events in patients treated conservatively,3,10,11 while others advocate for aggressive surgical management in all patients with os odontoideum to avert the risk of significant neurologic injury.8,12 Advocates of a generalized interventional approach argue that the presence of an os odontoideum causes the C1–2 region to become potentially unstable, citing cases in the literature where patients with os odontoideum have developed late neurologic compromise or suffered a spinal cord injury after minor trauma.8,12,13

  • A rare case of os odontoideum from an Early Intermediate period tomb at the Huacas de Moche, Peru

    2015, International Journal of Paleopathology
    Citation Excerpt :

    Also, with joint instability, there is the possibility that the atlanto-axial joint might dislocate with minor trauma, which may cause vertebral artery occlusion that can lead to brain stem infarction (Takakuwa et al., 1994). While some clinicians recommend surgical stabilization as a prophylactic procedure (Klimo et al., 2008), others suggest that not all patients with os odontoideum require surgery (Rozzelle et al., 2013); rather, only those with pain, neurological deficits, or progressive atlantoaxial instability (Dai et al., 2000:108). In the present case, while ligaments that stabilize the atlanto-occipital and atlanto-axial joints may have been stressed, as inferred from bony reaction at ligament attachment sites, it is probable that they maintained atlanto-axial stability.

  • Cervical Instability in Young Adults

    2015, Operative Techniques in Orthopaedics
    Citation Excerpt :

    Treatment of patients without neurologic symptoms, but with instability on flexion and extension radiographs, is less controversial with the American Association of Neurological Surgeons/Congress of Neurological Surgeons guidelines and most authors advocate a C1-C2 instrumented posterior fusion.1,2,8,10,11 However, it is worth noting that these recommendations are made in spite of no direct link between instability on flexion and extension radiographs and neurologic symptoms,3,14 but rather are based largely on the fact that large case series have demonstrated a high success rate of surgery in patients with instability.1,2,8,10,11 Cervical spine trauma in the pediatric patient presents a unique set of challenges to treating physicians.

View all citing articles on Scopus
View full text