The dens is a part of the axis, the second cervical vertebra. This consists of a body with vertebral arches and transverse processes and a bony process called the spine or tooth (dens). In a fracture (a broken bone) of the axis, the dens is most often involved, which is why this type of bone fracture is called a dens fracture.
What is a dens fracture?
A dens fracture is a break in the bony process of the second cervical vertebra. There are three different types of fractures according to Anderson-D’Alonso’s classification. Various ligaments attach to the dens axis, through which the motion of the cervical vertebrae is transmitted to the musculature. One of these ligaments is the ligamentum transversum.
- In type I fracture, the tip of the dens axis above this ligament is fractured at an angle.
- Type II is the most common of the dens fractures. Here, the fracture site is close to the base of the dens, close to the junction with the axis body.
- Type III already extends into the body of the axis.
Causes
Type I fracture is caused by overstretching of the ligamenta alaria. This can happen due to a severe injury with displacement of the upper cervical joints between the occipital bone and the first cervical vertebra. This causes the associated ligaments (ligamenta alaria) to tear off the bone, thereby causing the fracture. Type II fracture often results from falls. Falls to the face result in hyperextension injuries that shift the atlas vertebra backward, and falls to the back of the head result in hyperflexion traumas that are responsible for shifting the atlas forward. In both cases, a type II fracture can occur. In type III, a violent impact causes a vertebral displacement. This causes massive stretching of the ligament surrounding the dens axis (ligamentum transversum). If it does not tear during this stretching, it passes on the acting force to the vertebra, resulting in a fracture. Fractures of the dens often affect older people because the bones in older people become increasingly brittle. In younger people, the bone structure is still stronger, which is why ligament injuries are more likely to occur in them.
Symptoms, complaints and signs
The medical history is particularly important here, as the types of injuries are revealed based on the sequence of accidents. Injuries such as chin wounds, facial injuries, and head lacerations may already indicate a cervical injury. If a tilted posture of the head and neck is added to this, with pain and restricted movement of the upper cervical spine, there is even more evidence of such an injury. Palpatory localized tenderness as a major symptom suggests an upper cervical spine injury. Other symptoms include neck pain, dysphagia, and neurologic deficits.
Diagnosis
Diagnosis is made with imaging techniques. This may be a conventional x-ray of the upper cervical spine in three planes, but a computed tomography scan is more accurate. It makes injuries visible or more obvious that are often either not detected or underestimated in the x-ray.
Complications
Dens fracture can cause complications and pain in various locations around the neck. However, in most cases, injuries occur in the cervical vertebrae. In this case, the patient suffers from restricted movement, as the movements of the head and neck often lead to pain. As a result, the quality of life is also greatly reduced. Pain occurs in the neck and cervical region. These can occur either as pain at rest or as pressure pain. Swallowing difficulties are also common. Patients are no longer able to engage in sports or physical activities, which restricts their daily lives. In the worst case, the dens fracture can also paralyze the respiratory center, resulting in death. Treatment usually involves surgery and the use of a fixation device. Depending on the age, this can lead to various further complications, so that further surgery may be necessary. Life expectancy is not reduced by the dens fracture if it is treated in time and the patient does not expose himself to special stresses.
When to go to the doctor?
Since this complaint is a bone fracture, a doctor must be consulted in this case in any case. If the patient does not see a doctor, complications may arise in the further course if the bones do not fuse properly. As a rule, the doctor should be consulted if the patient feels very severe pain in the neck after an accident or after a blow. Loss of consciousness for a short time may also indicate the dens fracture. Similarly, the dens fracture leads to significant restrictions in movement and severe difficulty in swallowing, making it difficult to take food. A visit to a doctor is definitely necessary for these complaints as well. Similarly, severe neck pain may be indicative of the dens fracture and should therefore be examined. In acute emergencies or in case of very severe pain, the affected person should visit a hospital or call an emergency doctor. Further treatment is then provided by immobilizing the affected region.
Treatment and therapy
Type I fracture is considered stable and can be adequately treated with cervical bracing for one to two weeks. Type II fracture is critical. It is unstable and difficult to treat. Two treatment options are available. As conservative therapy, a halo vest is worn for twelve weeks. The halo vest fixes the head and allows the fracture to heal. Instead of the halo vest, a cervical orthosis is increasingly being used. Older patients in particular have fewer difficulties with this. One argument against conservative therapy is that pseudarthrosis develops in 35 percent to 85 percent of all cases. With conservative treatment, there is a risk of pseudarthrosis. The frequency of pseudarthrosis is also given as 35 to 85 percent. Denspseudarthrosis poses two major dangers. There may be acute paralysis of the respiratory center with tetraparesis (which is paralysis of all four limbs) or slowly progressive myelopathy. In myelopathy, the spinal cord is progressively damaged, due to growing pressure of the sphenoid arthroses. This can also lead to paralysis and even death. Whereby there are also patients with pseudarthrosis who are stable and have no complaints. In an untreated type II dens fracture, pseudarthrosis occurs in 100 percent of cases. Since conservative therapy is fraught with many risks, surgery is increasingly preferred even in elderly patients. An ideal surgical technique for stabilizing the type II dens fracture has not yet been found. Dorsal screw fixation of the cervical vertebrae C1 and C2 (atlas and axis) provides the greatest stability, but only limited movement of the head is possible. The loss of rotation is 50 percent. In addition, there is a risk of injuring the vertebral artery during surgery, and there may be greater blood loss during the procedure. Another option is ventral dens screw fixation. Here there is no loss of rotation and more rapid mobilization of the patient is possible, which is especially important in older patients. In this case, however, there is a higher incidence of dens pseudarthrosis and up to 20 percent of cases require further surgery. With additional ventral screw fixation of C1 and C2, an improvement in stability can be achieved. In this fracture, the type of treatment is a matter of consideration. The decisive therapeutic goal is rapid mobilization and reintegration of an elderly patient. The type III dens fracture can be treated conservatively. Here, pseudarthroses rarely form and the patient must wear a halofixator or a cervical orthosis for ten to twelve weeks. Surgery is rarely necessary.
Outlook and prognosis
In any case of a dens fracture, affected individuals are dependent on treatment. There is no self-healing in this disease and in many cases unbearable pain, so treatment is necessary in any case. Those affected suffer from severe movement restrictions and also from pain in the neck or head. This can lead to difficulty swallowing, and the pain often spreads to neighboring regions of the body. The patient’s quality of life is considerably reduced and limited by the dens fracture. In the further course, it can also lead to neurological deficits and further to sensory disturbances.The treatment of the dens fracture always depends on the exact complaints and symptoms and can limit them relatively well. The fracture is straightened by surgical intervention. The surgical intervention is often no longer performed in older people, so that they are dependent on conservative therapy. This may not result in complete healing and the movement of the head remains restricted. Life expectancy is usually reduced by the dens fracture only if it negatively affects the patient’s respiratory function.
Prevention
Dens injuries are usually consequences of accidents involving the head. Typical of these are traffic accidents or even sports accidents, falls while horseback riding or skiing, or jumping head first into unfamiliar waters that are too shallow. In elderly people, even a simple fall can be sufficient. Only adequate safety measures offer protection. Sensible behavior in road traffic. A roadworthy car with airbags, properly adjusted neck restraints and good seat belts. Observing safety rules and wearing helmets and protective clothing during sports and at work. For the elderly, treatment of circulatory problems is important to prevent fainting and dizziness that can lead to falls.
Aftercare
A dens fracture is a fracture of the cervical vertebra that often occurs in older people when they fall forward. In order to be able to ensure an optimal and complication-free course of the disease, regular examinations should take place at the doctor to be treated. Otherwise, there is a risk that this type of fracture will not grow together properly. If the affected person decides to make regular visits to the doctor, then absolutely nothing stands in the way of a full recovery. By means of ventral screw fixations, the fracture can be fixed so that it can grow together firmly and stably. However, appropriate follow-up examinations are of great importance, since such foreign bodies can always cause complications. If you want to avoid all complications, it is imperative that you make use of the above-mentioned aftercare examinations. Regular visits to the doctor can ensure a complete and timely recovery. However, if the affected person completely forgoes such follow-up care, then under certain circumstances even serious consequential damage can occur. A dens fracture is a medical condition that should definitely be treated medically and with medication. Follow-up examinations should also take place to ensure a full recovery. If these do not take place, the affected person must expect significant complications or permanent consequential damage.
What you can do yourself
If a dens fracture is suspected, a doctor must make the diagnosis and immediately initiate surgical treatment. After surgery, some self-help measures make everyday life with a dens fracture easier. First and foremost, these include rest and bed rest. The back and cervical vertebrae must not be loaded during the first days and weeks after the operation. Further medical examinations are required to rule out neurological damage. If unusual symptoms are noticed, this must be discussed with the doctor in charge. Accompanying physiotherapy and light sports, but also yoga or Pilates are recommended. Massages help against tension as a result of splinting. Long-term consequences are not to be expected with a dens fracture. Those affected must therefore be prepared for pain and restricted movement, especially in the first weeks and months after the accident or fall. To ensure that the return to everyday life goes smoothly, it is important to talk to other sufferers. In forums and self-help groups, patients with a dens fracture can obtain tips on suitable sports, any dietary measures (especially for type II dens fractures) and possible accompanying symptoms. As a result, and through conventional medical treatment, a dens fracture can usually be cured quickly and relatively painlessly.
