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Atlas Fracture Overview

Last updated on: October 3, 2024

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Atlas Fractures constitute approximately 7% of cervical spine fractures and are rarely associated with neurological injury. This is because of the large amount of space available for the cord. 50% of these injuries are associated with other cervical spine fractures, especially odontoid fractures and spondylolisthesis of the axis.

The mechanism of injury is axial compression with elements of hyperextension and asymmetric loading of the condyles causing variable fracture patterns.

Atlas Fracture Diagnosis

Clinical symptoms include headache and suboccipital pain with limitation of movement. Cranial nerve lesions of VI–XII and neurapraxia of the suboccipital and greater occipital nerves may be associated. Damage to the spinal cord is uncommon because a significant cord injury at this level causes immediate death.

Vertebral artery injuries may cause symptoms of basilar insufficiency such as vertigo, blurred vision and nystagmus.

Anteroposterior films, including an open-mouth view and a lateral view, and CT scanning are performed. The common fracture sites are the anterior arch, either midline or just lateral to the midline, and the posterior arch at its narrowest portion just posterior to each lateral mass.

See Also: Occipitocervical Dissociation

Atlas Fracture Classification

Landells Atlas Fractures Classification

Type	Description	Treatment
Type I	– Isolated anterior or posterior arch fracture. – A “plough fracture is an isolated anterior arch fracture caused by a force driving the odontoid through the anterior arch.	– Stable. – Treat with hard collar.
Type II	Jefferson burst fracture with bilateral fractures of anterior and posterior arch resulting from axial load.	Stability determined by integrity of transverse ligament: – If intact, hard collar. – If disrupted, halo vest (for bony avulsion) or C1-2 fusion (for intrasubstance tear)
Type III	Unilateral lateral mass fx.	Stability determined by integrity of transverse ligament: – If stable, treat with hard collar. – If unstable, halo vest.

Atlas Fracture stability is based on the integrity of the transverse ligament. If the transverse ligament is disrupted, the C1 injury is considered unstable. It is important to recognize this instability as the management is different from stable burst fractures.

In open-mouth radiographs, if the combined lateral mass overhang is 7 mm or more, rupture of the transverse ligament has probably occurred. The integrity of the ligament can also be evaluated by measuring the atlantodens interval on the lateral view.

An atlantodens interval >3 mm in adults is indicative of a ligament insufficiency. Transverse ligament insufficiency may also be diagnosed directly by identifying bony avulsion on CT scan or ligament rupture on MRI.

See Also: Occipital Condyle Fractures

Atlas Fracture Treatment

Isolated anterior or posterior arch fractures, transverse process fractures and undisplaced/ minimally displaced lateral mass fractures can be treated conservatively with 6–12 weeks of immobilization in a rigid cervical collar.

Stable burst fractures (intact transverse ligament) can be treated in a rigid cervical collar or a halo vest.

Unstable burst fractures (disruption of the transverse ligament) should be reduced with halo traction. Halo traction should be maintained for 3–6 weeks before application of a halo vest, which is worn for a further period of 6 weeks. These injuries can also be treated surgically through a posterior C1–2 fusion.

Atlas Fracture treatment posterior C1–2 fusion

References & More

Mercer’s Textbook of Orthopaedics and Trauma, Tenth edition.
Levine AM, Edwards CC. Treatment of injuries in the C1-C2 complex. Orthop Clin North Am. 1986 Jan;17(1):31-44. PMID: 3945481. Pubmed
Kim D, Viswanathan VK, Munakomi S, et al. C1 Fractures. [Updated 2023 Aug 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: Pubmed