Traumatic atlantoaxial rotatory subluxation in an adolescent: a case report
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Atlantoaxial rotatory subluxation is rarely caused by trauma in adults. Usually, the treatment of choice is traction using Halo/Gardner-Wells fixation devices for up to six weeks.
We present the case of a 19-year-old Caucasian woman with traumatic atlantoaxial subluxation. Early reduction three hours after trauma and immobilization using only a soft collar were performed and yielded very good clinical results.
In the adult population, atlantoaxial subluxation is a rare condition but is severe if untreated. Early treatment implies a non-surgical approach and a good outcome. Conservative treatment is the recommended first step for this condition.
KeywordsCervical Spine Down Syndrome Marfan Syndrome Anterior Displacement Atlantoaxial Joint
Atlantoaxial rotatory subluxation is frequently observed in children and in patients with rheumatic arthritis, but rarely occurs traumatically in adults . A typical clinical sign is torticollis  with lateral flexion of the neck and contralateral rotation, known as the Cock-Robin position . Usually, the treatment of choice is traction using Halo/Gardner-Wells fixation devices for up to six weeks . The importance of recognizing this condition stems from the fact that it has the potential to cause severe neural damage or even death if it is not treated promptly .
We present the case of a patient with traumatic atlantoaxial subluxation in which early reduction, three hours after trauma and immobilization using only a soft collar were performed and yielded very good clinical results.
The atlantoaxial joint is stabilized in the anteroposterior plane by transverse ligaments and the joint capsule. The alar ligaments pass from the lateral occipital processes to the posterolateral margins of the odontoid apex and their main function is to prevent excessive rotation of this joint. The normal range of rotation is 40 degrees to each side . These rotational movements imply a displacement of C1 over C2, leading to a loss of contact surface between the corresponding facets on each side. In the case of alar ligament disruption, the rotational angle is less than 36 degrees and the contact surface between the facets is less than 60% [6, 7]. These are the features that comprise the diagnosis of atlantoaxial subluxation. Therefore, the rotational mismatch between atlas and axis alone is not a valuable parameter to assess the presence of atlantoaxial subluxation and an imaging oriented classification is used.
Atlantoaxial subluxation occurs rarely in the adult population and it is only responsible for 2.5% of all the spinal afflictions . It is predominate in the pediatric population due to an enhanced elasticity of ligaments, horizontally oriented, shallower joint surfaces of the lateral masses, a not fully developed neck musculature and a bigger head-body relationship .
Also, conditions that enhance ligamentous laxity such as: Down Syndrome, Morquio Syndrome and Marfan Syndrome, correlate with a higher incidence of rotatory subluxation .
The importance of recognizing this condition is the fact that it has the potential to cause severe neural damage, long term sequelae and even death if not treated promptly. The time between the injury and the reduction is crucial as it directly correlates with the prognosis. If untreated after one to three months it becomes irreducible and requires a surgical approach [5, 10]. Due to its lower incidence rate, this condition is frequently undiagnosed or the diagnosis is delayed and the outcome is worse .
Traditionally, cervical radiography was used to establish a diagnosis. It showed the persistent rotation of the odontoid peg in relation to the lateral masses of the atlas. Currently, the method for diagnosis is the dynamic unenhanced cervical CT scan, usually performed with multiple 1 mm or 3 mm collimation, and post-imaging three-dimensional reconstruction . It allows an easier interpretation, follow-up and classification, according to Fielding and Hawkins :
Type 1: rotatory subluxation without anterior displacement of the atlas (atlanto-odontal interval ≤3 mm)
Type 2: rotatory subluxation with anterior displacement of the atlas of 3 mm to 5 mm
Type 3: rotatory subluxation with anterior displacement of the atlas of > 5 mm
Type 4: rotatory subluxation with posterior displacement of the atlas.
As mentioned above, the delay between injury and reduction predisposes to the recurrence of this condition and the failure to heal after non-surgical management with the consequent loss of mobility of the upper cervical spine .
The management goals of a patient with this condition are to treat the instability of the atlantoaxial joint, restore and prevent possible effects of neurological compromise and to achieve the normal pain-free motion of this joint. Conservative treatment using analgesics, with halter traction or closed reduction maneuvers, is the first step in the treatment of this condition [6, 8, 13, 14].
The decision to take a surgical approach is based on the stability of the joint, its re-dislocation and on the compromise of the transverse alar ligaments. Compared to conservative management, the arthrodesis of the atlantoaxial joint results in a loss of rotation to each side and therefore it is not recommended as the initial treatment .
In patients with diagnosed lesions of the cervical spine, concomitant injuries have to be considered. In our case, the patient had an additional epidural hematoma or disc protrusion on level C5/6. This injury might pose a danger to the patient during a closed reduction maneuver if the patient's awareness is impaired. Therefore, it is necessary to perform both CT and MRI before reduction on these patients. In our case, however, the patient was awake and would have been able to report any new paresthetic sensations. There was neither fracture nor instability nor rupture of alar ligaments. This qualified her for conservative management. Some authors suggest treatment with traction and a subsequent halo body jacket for eight to 12 weeks for these patients [8, 16].
It has been shown that wearing soft collars produces less motion of the cervical spine in conscious patients , even though it would work more likely as a reminder to the patient to restrict his or her own motion . This is especially important to avoid the critical end range rotation.
It was decided that the patient, being very young, and therefore having ligaments of higher elasticity , be immobilized in a soft collar for six weeks. To the best of our knowledge this is the first time this treatment has been reported for atlantoaxial subluxation, without the need for halo fixation and while achieving a good clinical outcome.
Atlantoaxial subluxation is a rare, but severe if untreated, condition in the adult population. The best way to ensure the diagnosis properly is by using a dynamic unenhanced cervical CT with posterior three-dimensional reconstruction. The delay between injury and management affects the prognosis. Early treatment implies a non-surgical approach and a better outcome. Conservative treatment is the first step with this condition.
Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
- 11.Wang K, Loke TKL: Computed tomography of paediatric atlanto-axial rotatory subluxation: the multiple image addition method. J HK Coll Radiol. 2001, 4: 209-212.Google Scholar
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