Review Question - QID 219425

This patient presents with clinical and radiographic evidence of atlantoaxial rotatory displacement (AARD). Most cases of acute AARD (i.e., <4-8 weeks of symptoms) resolve with nonoperative management consisting of applying a soft collar and analgesics. Given the rarity of this diagnosis, there is variation in commonly accepted treatment protocols, although modern literature suggests a minimum of two weeks of supportive care is warranted prior to utilization of traction (Answer 2).

Atlantoaxial rotatory displacement (AARD) is a rare condition typically presenting in the pediatric population with neck pain and acute torticollis due to rotational misalignment of the atlantoaxial joint, often triggered by infection, trauma, recent head or neck surgery, or congenital abnormalities. Rather than a distinct clinical entity, it is believed that this condition exists on a spectrum, ranging from muscle spasm to a fixed mechanical block to reduction. History and physical exam are paramount for establishing clinical suspicion, with imaging modalities such as radiographs, CT (which may be performed dynamically to assess for abnormalities in motion at the C1-2 articulation with head rotation), or MRI used to confirm or classify severity, exclude other causes, or monitor treatment response. Multiple classification systems exist, subdividing AARD based on various parameters such as direction and amount of displacement, motion characteristics of the C1-2 joint, or C2 facet deformity. The Fielding and Hawkins classification (displayed below in Illustration 1) is most commonly utilized in clinical practice. Early treatment, including analgesics and application of a cervical collar, is crucial for acute cases, while persistent, chronic or refractory cases may require Halter traction, skeletal traction, or C1-2 arthrodesis. A step-up strategy based on chronicity and symptom resolution, as summarized below, is currently accepted as an effective, pragmatic approach to treatment.

Lawson and Dormans reviewed cervical spine disorder in the pediatric population. They underscore the importance of understanding the developmental anatomy and common radiographic features of the cervical spine in this population during the evaluation and review a multitude of congenital and acquired cervical spine abnormalities. In the discussion of AARD, they recommended a trial of conservative management with NSAIDs and soft collar for up to one week: however, more recent literature suggests a minimum of two weeks of treatment with conservative measures is warranted prior to utilization of traction.

Neal and Mohamed provided a more modern review of AARD in children. They suggested that diagnosis is primarily clinical, but potentially aided by the above-mentioned imaging modalities and laboratory testing (e.g., CBC, ESR, CRP), emphasizing the importance of considering underlying infection or inflammatory causes. For acutely presenting cases, the authors proposed a treatment algorithm utilizing a step-up approach and 2-week intervals of progressively invasive treatment modalities should torticollis persist despite treatment. In other words, they recommended two-week trials of the following modalities, in sequential order: cervical collar and NSAIDs, halter traction with benzodiazepines (to assist with muscle spasm) and NSAIDs, skeletal traction with the same medications, and lastly, C1-2 arthrodesis. They concluded that the time from symptom onset to treatment initiation is the most critical factor for successful conservative management.

Figure A is an anteroposterior radiograph of the cervical spine demonstrating loss of symmetry between lateral masses of the atlas and odontoid process, suggestive of AARD.
Illustration 1 summarizes the Fielding and Hawkins classification system for AARD.

Incorrect Answers:
Answer choices 1, 3, and 4: For most acute cases of AARD which present with <2 weeks of symptoms as in this patient, a trial of at least two weeks of conservative management is recommended prior to initiation of traction or consideration of arthrodesis.
Answer choice 5: Removing immobilization and beginning stretching would be unlikely to aid in resolution as this patient has clinical and radiographic evidence of persistent subluxation, thus at minimum continued cervical collar immobilization is warranted.