odontoid fracture

Fracture of the odontoid: what consequences? (Is that bad ?)

Article reviewed and approved by Dr. Ibtissama Boukas, physician specializing in family medicine

The vertebrae cervical have the role of ensuring the solidity and the mobility of the neck. Seven in number, they are numbered from C1 to C7, the first of which is called “atlas” and the second “axis”. These vertebrae are located at the neck, between the head and the thorax. An accident, a fall or even a trauma can beorigin of cervical fractures. In this article, let's take a look at the axis fracture (C2), also called " odontoid fracture ».

Odontoid fracture: definition


It is important to see theanatomy of the odontoid process for better understand odontoid fracture.


Anatomy of the odontoid process


On its upper surface, the axis has a voluminous vertical process in pyramidal form called " axis tooth "," odontoid process " or " odontoid process ».


This odontoid process has two ligaments:


  • the transverse ligament which allows it to articulate with the atlas;
  • the apical ligament which allows it to be attached to the occipital bone of the head.


The particularity of the morphology of the axis gives it a very important function in the mobility of the neck. The odontoid process plays a pivotal role. This is what makes possible the rotation of the atlas and the head (90° left and right).


Odontoid fracture


The odontoid fractures account for about 60% of fractures of the axis with a frequency that oscillates between 7 and 14%. In subjects over the age of 70, they constitute fractures of the cervical spine the most common in the event of a fall. On the other hand, in young subjects, they can follow multiple traumas.


In addition to falls and polytrauma, odontoid fractures can also be linked to other pathologies such as:


  • a osteoporosis (progressive loss of bone density weakening the bones);
  • work or traffic accidents (whiplash ou cervical sprain);
  • shocks during a sporting activity;
  • suicide attempts by hanging (hangman's fracture).



Classification of odontoid fractures


According to Anderson and Alonzo classification, we can distinguish 3 types of odontoid fractures.


  • Type I: it is an avulsion fracture. It is rare and stable. The fracture line is located at the level of the tip of the odontoid and gives a tearing appearance.
  • Type II: it is an unstable fracture whose fracture line is located at the level of the neck of the odontoid. In the elderly, this type of fracture exposes you to the risk of pseudarthrosis.
  • Type III: it is a stable fracture with a line crossing the vertebral body of the C2 or the base of the odontoid.


types of odontoid fracture


During a stable fracture, soft tissues and ligaments are not affected and the Spinal canal remain intact. On the other hand, if the fracture is unstable, discs, ligaments and joints are damaged. The spinal canal may be constricted and bone fragments may injure the spinal cord in the worst case.



What are the symptoms of an axis fracture?


Le main symptom of fracture of the odontoid is a severe localized neck pain (acute neck pain). This can radiate to the shoulder or arm (cervico-brachial neuralgia). Sometimes, deformations can be observed. They can cause functional disorders such as balance disorders.


If you have a sliding of vertebrae or bone debris, this fracture can cause a spinal cord compression. If the phrenic nerve is damaged, it is possible that the patient suffers from ventilatory disorders. The diaphragm is the main muscle of respiration.


This type of neurological pathology remains rare due to the extent of the cervical vertebral canal. As it is wider than that in the vertebrae of the upper dorsal region, the spinal cord is less tight.



How to make the diagnosis of odontoid fracture?


Usually the diagnosis of this type of cervical fractures is based on a first clinical examination. It consists of :


  • assess pain;
  • check for stiffness in the neck;
  • palpate a possible hematoma.


The doctor will then prescribe different types of imaging tests to confirm the diagnosis and choose the appropriate treatment.




This technique ofmedical imaging uses x-rays to highlight the site of the fracture. In the same way, it makes it possible to check the presence ofdislocation of the first vertebrate cervical (C1). To obtain these results, the doctor uses a standard frontal and profile X-ray.


A scanner to assess the fracture of the odontoid


It makes it possible to take cross-sectional images using an X-ray beam. In the event of a fracture of the odontoid, it makes it possible to visualize the bone anatomy of the fracture. In other words, it makes it possible to determine the type of fracture and to specify the extension of the fracture line.


An MRI (Magnetic Resonance Imaging)


MRI is necessary if there are signs of neurological involvement such as paralysis or numbness.


It gives very precise images which make it possible to clearly appreciate the damage to the nervous structures and the integrity of the transverse ligament.



How to treat odontoid fracture?


Le odontoid fracture treatment may vary from patient to patient. It may depend on the type of fracture, the patient's age, neurological signs, etc.


Medical treatment


Le medical treatment is to deal with pain. For this, the doctor usually prescribes paracetamol or nonsteroidal anti-inflammatory drugs (NSAIDs).


If these drugs prove insufficient against pain, an analgesic reserved for more intense pain may be prescribed.


Orthopedic treatment of a fracture of the axis


Le orthopedic treatment can go hand in hand with drug treatment. It consists of stabilizing the neck with a cervical collar, a resin or plaster corset.


The duration of treatment can range from a few weeks to several months. In the majority of cases, this type of processing is intended for:


  • elderly patients;
  • patients who have a contraindication to surgery;
  • slightly displaced fractures;
  • to patients with no neurological symptoms.


Surgical treatment of an odontoid fracture


Le surgical treatment for fracture of the axis is mainly reserved:


  • unstable fractures (type II);
  • to young subjects;
  • to patients with neurological disorders.


It is used, among other things, to remedy the compression of the spinal cord. Depending on the location of the compression, the operation can be done either anteriorly or posteriorly.


This type of treatment can also correct the deformation of the spine. In this case, the vertebrae are fixed with a screw, plates, hooks or rods (osteosynthesis). To ensure optimal healing, it should ideally be performed within 6 hours of the accident.


A rehabilitation phase in physiotherapy should always follow a surgery for an odontoid fracture.



What are the complications of cervical fracture?


In most cases, the treatment of the fracture of the odontoid process gives good results. It is only in the case of neurological disorders that complications can arise. Indeed, compression of the spinal cord can lead to:


  • voltage drop;
  • nerve tissue necrosis;
  • motor or sensory disturbances;
  • tetraplegia (paralysis of the arms and legs) if the spinal cord is severed in this region;
  • dysfunction of the rectum, bladder (incontinence) and sexual functions (rare);
  • death by asphyxiation in the event of damage to the phrenic nerve.









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