During the period 2004 – 10, six children between seven and 14 years of age underwent surgery for atlantoaxial rotatory fixation at Oslo University Hospital, Rikshospitalet. Full reduction was achieved in two of the children and partial reduction in three. The sixth child had bone fusion at the time of the operation, and it was not possible to correct the damage surgically.
Five of our six patients had suffered minor neck trauma, while the sixth had had tonsillitis. In a large material sample the condition was normally found to be related to upper respiratory tract infection (35 %), minor trauma (20 %) or surgical procedure of the throat or neck (20 %), while in the remainder of cases the cause was unknown (9). While the male sex is overrepresented in spinal injuries (22, 23), in the case of atlantoaxial rotatory fixation there is a preponderance of females, some 70 – 80 % (9, 23). In our material sample, half the patients were girls.
Prior to the introduction of CT scanning, diagnosis of atlantoaxial rotatory fixation was based on conventional X-ray examination (24). However, the results are frequently difficult to interpret in a child with displacement of the atlantoaxial joint (6, 24) – (26), although X-ray examination is still regarded as a useful supplement to the assessment in order to exclude other pathology, such as congenital malformations or spinal tumour (27). A static CT scan is able to show a displacement between the atlas and axis, although it has its limitations in that it is unable to demonstrate the dynamic relationship between the atlas and axis on rotation (27, 28). A dynamic CT scan of a child who rotates its head maximally to one side will as a normal finding show the atlas rotating approximately 23° on the axis before it starts rotating with the atlas (29). To verify a fixed rotational displacement, a dynamic CT scan, where the images are taken with the head rotated maximally to the right, the left and straight forward, is the best method. Only then is it possible to see whether the displacement in the joint can be corrected by rotation of the neck. If there is little or no change in the displacement subluxation at rotation, the radiological conclusion is atlantoaxial rotatory fixation (27, 28, 30). This method of examination is recommended for mapping the anatomical conditions in the upper cervical spine in children (31).
Torticollis in children can have different causes, and a persistent twisted neck position should always be more closely investigated. The most common cause in children is congenital muscular torticollis (8). This condition is caused by the contraction and gradual contracture of the sternocleidomastoid muscle on the opposite side of the one to which the head is rotated. Such muscle spasm is not normally found in atlantoaxial rotatory fixation (20). However, our patient with total luxation of the atlantoaxial joint did have contracture of the muscle. Three of our patients had suspected juvenile rheumatoid arthritis prior to surgery, and two have since been given that diagnosis. It is uncertain whether there is a connection between these conditions, but one theory is that rotatory fixation can occur as a result of greater laxity of the ligaments and synovial thickening in juvenile rheumatoid arthritis (32).Concurrence is also described in a case study from 2011 (33). We believe, therefore, that it is important to undertake a broadly based assessment of children with atlantoaxial rotatory fixation in order to exclude juvenile rheumatoid arthritis. If the cause of torticollis in children cannot be found, the possibility of tumour must be excluded. Tumour of the skull base (posterior fossa tumour) can compress/affect nerve structures which innervate the neck muscles and thus give rise to secondary torticollis (34).
Most cases of torticollis caused by ligament or muscle damage respond well to analgesics and anti-inflammatory medication. Most frequently, spontaneous improvement and normalisation of the displacement are achieved within a week (35). However, when the cause is atlantoaxial rotatory fixation the condition may persist despite medication or a cervical collar. Where an early diagnosis is made, it is however possible for most patients with this condition to be treated successfully with closed reduction without sequelae. Some patients in the early phase even achieve reduction during light manipulation in connection with examination and X-ray diagnostics. With a case history of up to 30 days, anti-inflammatory and, possibly, muscle-relaxant medication should be tried for 1 – 2 weeks combined with light traction and a cervical collar (22). Where traction is started within 30 days of symptom onset, the result in 90 % of cases is reduction and normal movement at the atlantoaxial joint (11).
If attempts at reduction and to relieve pain and improve movement are unsuccessful, one should attempt closed reduction with skull traction, physiotherapy and muscle relaxants. Patients lie in skull traction for an average of two weeks. After a CT scan has confirmed that the displacement is reduced, the patient wears a cervical collar for six weeks. Individual patients do however reluxate twice on average (11), and some doctors then recommend a renewed attempt at reduction (9, 22). It has been shown that for up to 2 – 3 months after the onset of torticollis, traction combined with a cervical collar is usually sufficient to correct the displacement (6, 9, 36) – (38). Where atlantoaxial rotatory fixation persists for more than 2 – 3 months, most attempts at closed reduction are unsuccessful (9, 36, 38) – (40), and surgical treatment with open reduction and internal fixation may be necessary (2, 6, 39, 41, 42).
To our knowledge, only one prospective study has been done of the diagnosis, treatment and outcomes of atlantoaxial rotatory fixation (42). The recommended therapeutic strategy is otherwise based chiefly on retrospective follow-up studies.
Our experience with unsuccessful attempts at closed reduction in three patients with symptom duration of more than five months is in line with reports that skull traction is not sufficient to reduce late-diagnosed atlantoaxial rotatory fixation (14, 37). The condition can be life-threatening (2) and instances of «sudden death» have been described in connection with attempts at closed reduction of a fixed abnormal rotational position of the atlantoaxial joint (6).
Surgical treatment of atlantoaxial rotatory fixation does not lead to normalisation of the anatomical conditions in the neck. Rotational movement after surgical fixation is reduced by about 25 % (6). In 30 % of patients it has also been shown that a process of degeneration arises at the adjacent level within ten years of surgical fixation (16). The consequences of unsuccessful reduction and persistent displacement are however so great that we believe surgery is the best therapeutic alternative after one unsuccessful attempt at closed reduction. In the case of severely delayed diagnosis, open reduction and fixation should be done without first attempting closed reduction.
Limitations in this review are owing to the small and selective patient sample, that the data were obtained retrospectively and that we have had no comparison groups. Thus it is difficult to create guidelines for the treatment of this patient group on the basis of our material. However, there is an international tendency towards surgical treatment of atlantoaxial rotatory fixation in excess of three months, although the point in time for recommended surgical intervention varies (6, 42).