Aims. Although atlantoaxial rotatory fixation (AARF) is a common cause of torticollis in children, the diagnosis may be delayed. The condition is characterised by a lack of rotation at the atlantoaxial joint which becomes fixed in a rotated and subluxed position. The management of children with a delayed presentation of this condition is controversial. This is a retrospective study of a group of such children. Patients and Methods. Children who were admitted to two institutions between 1988 and 2014 with a diagnosis of AARF were included. We identified 12 children (four boys, eight girls), with a mean age of 7.3 years (1.5 to 13.4), in whom the duration of symptoms on presentation was at least four weeks (four to 39). All were treated with halo traction followed by a period of cervical immobilisation in a halo vest or a Minerva jacket. We describe a simple modification to the halo traction that allows the child to move their head whilst maintaining traction. The mean follow-up was 59.6 weeks (24 to 156). Results. Despite the delay in referral, the subluxation was successfully reduced in all children. Only two children required atlantoaxial fusion. Conclusion. The results of our study suggest that normal anatomy with restoration of movement may be achieved even in cases of AARF presenting late, obviating the need for fusion. We also show a simple modification to the halo traction that allows the child to move their head about while still maintaining traction. Take home message: Prompt diagnosis and management with halo traction (with a simple modification as described) is associated with good results in patients with AARF who present late. Cite this article: Bone Joint J 2016;98-B:715–20

We evaluated the use of surgical stabilisation for atlantoaxial subluxation after a follow-up of 24 years in 50 rheumatoid patients who had some degree of pain but no major neurological deficit. The mortality of patients treated by atlantoaxial fusion was significantly lower than for those who received conservative treatment. The deaths resulted from infection or comorbid conditions. The significantly high relative risks of mortality from conservative treatment compared with surgical treatment were mutilating disease and susceptible factors on both of the HLA-DRB1 alleles. Relief from pain and neurological and functional recovery were better, and the radiological degree of atlantoaxial translocation was less in those who were surgically treated compared with those who were not. Two patients had superficial local infections after surgery. We conclude that prophylactic atlantoaxial fusion is better than conservative treatment in these patients

We present seven children with atlantoaxial rotatory fixation (AARF) of more than three months’ duration after an injury to the upper cervical spine. The deformity was irreducible by skull traction. MRI and MR angiography (MRA) of the vertebral arteries were performed in four children. The patients were neurologically intact. Thrombosis of the ipsilateral vertebral artery was noted in two patients. The deformity was gradually corrected and stabilised after transoral release of the atlantoaxial complex, skull traction and posterior atlantoaxial fusion. Soft-tissue interposition and contractures within the atlantoaxial complex prevented closed reduction. MRI and MRA of the vertebral arteries were useful in elucidating the pathology of chronic atlantoaxial rotatory fixation

Transarticular screw fixation with autograft is an established procedure for the surgical treatment of atlantoaxial instability. Removal of the posterior arch of C1 may affect the rate of fusion. This study assessed the rate of atlantoaxial fusion using transarticular screws with or without removal of the posterior arch of C1. We reviewed 30 consecutive patients who underwent atlantoaxial fusion with a minimum follow-up of two years. In 25 patients (group A) the posterior arch of C1 was not excised (group A) and in five it was (group B). Fusion was assessed on static and dynamic radiographs. In selected patients CT imaging was also used to assess fusion and the position of the screws. There were 15 men and 15 women with a mean age of 51.2 years (23 to 77) and a mean follow-up of 7.7 years (2 to 11.6). Stable union with a solid fusion or a stable fibrous union was achieved in 29 patients (97%). In Group A, 20 patients (80%) achieved a solid fusion, four (16%) a stable fibrous union and one (4%) a nonunion. In Group B, stable union was achieved in all patients, three having a solid fusion and two a stable fibrous union. There was no statistically significant difference between the status of fusion in the two groups. Complications were noted in 12 patients (40%); these were mainly related to the screws, and included malpositioning and breakage. The presence of an intact or removed posterior arch of C1 did not affect the rate of fusion in patients with atlantoaxial instability undergoing C1/C2 fusion using transarticular screws and autograft. Cite this article: Bone Joint J 2013;95-B:972–6

We reviewed the outcome of a retrospective case series of eight patients with atlantoaxial instability who had been treated by percutaneous anterior transarticular screw fixation and grafting under image-intensifier guidance between December 2005 and June 2008. The mean follow-up was 19 months (8 to 27). All eight patients had a solid C1–2 fusion. There were no breakages or displacement of screws. All the patients with pre-operative neck pain had immediate relief from their symptoms or considerable improvement. There were no major complications. Our preliminary clinical results suggest that percutaneous anterior transarticulation screw fixation is technically feasible, safe, useful and minimally invasive when using the appropriate instruments allied to intra-operative image intensification, and by selecting the correct puncture point, angle and depth of insertion

In normal, physiological circumstances there is ample room in the spinal canal to accommodate the spinal cord. Our study aimed to identify the degree of compromise of the spinal canal which could be anticipated in various atlantoaxial pathological states. We examined paired atlas and axis vertebrae using high-definition radiography and simultaneous photography in both normal and simulated pathological orientations in order to measure the resultant dimension of the spinal canal and its percentage occlusion. At the extreme of physiological axial rotation (47°) the spinal canal is reduced to 61% of its cross-sectional area in neutral rotation. The spinal cord is thus safe from compromise. Atlantoaxial subluxation of up to 9 mm reduces the area of the spinal canal, in neutral rotation, to 60% with no cord compromise. Any rotation is, however, likely to cause cord compression. The mechanism of fixation in atlantoaxial rotatory subluxation could be explained by bony interlocking of the facet joint, reproducible in dry bones

Aims: To evaluate whether the atlantoaxial disorders (anterior atlantoaxial subluxation and atlantoaxial impaction) associate with destruction of shoulder or peripheral joints, and bone mineral density (BMD) in patients with long-term rheumatoid arthritis (RA). Methods: An inception cohort 67 patients with seropositive and erosive RA were followed up for 20 years. Cervical spine, shoulder, hand and foot radiographs, and the BMD of the lumbar spine and femoral neck were evaluated. Results: A positive relationship was detected between the occurrence of atlantoaxial disorders and the destruction of both shoulder (p < 0.001) and peripheral (p = 0.001) joints. In addition, the severity of atlantoaxial disorders positively correlated with the grade of destruction in the evaluated joints. Furthermore, a positive relationship was found between the occurrence of the atlantoaxial disorders and a decrease in BMD of the femoral neck (p = 0.019). Conclusions: Patients with severe RA and osteoporosis have an increased risk for atlantoaxial disorders, therefore the cervical spine radiographs of these patients should be analysed before major surgery and also at regular intervals. The co-existence of shoulder and cervical spine disorders makes the differential diagnosis of shoulder and neck pain challenging

Fracture of the atlas is rare in children. We report a case of fracture of the atlas through a synchondrosis of the anterior arch complicated by atlantoaxial rotatory fixation in a four-year-old girl

Background. Rotatory subluxation of the atlantoaxial joint has been thoroughly documented in children. However, pure traumatic atlantoaxial rotatory subluxation (TAARS) is a rare injury in adults with only a few cases reported in the English literature. Aim. To report two cases of TAARS in adults. Methods. A case note, clinical and radiological review. Results. Both patients were female. There was a history of a motor vehicle collision in both cases. There was no neurological impairment at presentation in either case. The injury in both cases was identified by plain X-ray and confirmed by CT scan. Both were managed by conservative treatment, initially with halo traction, followed by immobilisation in a rigid collar. Final clinical reviews occurred at 7 years and 2.5 years following injury. Neither patient had signs of C1-C2 instability or impaired neurology. Both patients, however, suffered headaches and occipital neuralgia, with stiffness and reduction in cervical spine movement. Conclusion. Traumatic rotatory subluxation in adults is a rare injury. It can pose a diagnostic challenge and CT scanning is mandatory for a correct evaluation of the C1-2 complex. Reduction and stability can be achieved through conservative treatment. However, it is evident from this short series that even early diagnosis and prompt reduction may not necessarily result in a good long term outcome in adult patients with TAARS

Three-dimensional CT was used to examine the atlantoaxial joint of a nine-year-old girl who presented with fixed rotation of the head 3.5 months after an apparently spontaneous acute torticollis. The method provided clear, anatomical images to show the site, extent and direction of the type-I rotatory fixation (Fielding and Hawkins 1977). The 3-D reconstructions helped to guide manipulation which was successful in this late case

Ankylosing spondylitis (AS) is a progressive multisystem chronic inflammatory disorder. The hallmark of this pathological process is a progressive fusion of the zygapophyseal joints and disc spaces of the axial skeleton, leading to a rigid kyphotic deformity and positive sagittal balance. The ankylosed spine is unable to accommodate normal mechanical forces, rendering it brittle and susceptible to injury. Traumatic hyperextension injury of the cervical spine leading to atlantoaxial subluxation (AAS) in AS patients can often be fatal. We report a non-traumatic mechanism of injury in AS progressing to AAS attributable to persistent hyperextension, which resulted in fatal migration of C2 through the foramen magnum. Cite this article: Bone Joint J 2013;95-B:206–9

Objective: To review the clinical outcome of 37 consecutive patients undergoing C1– C2 transarticular fixation for patients with Rheumatoid Arthritis. Design: Prospective Observational Study. Methods: There were 37 patients at 2 centres. Age range was 37– 82 years. The time since diagnosis to treatment was 2– 23 years. Clinical presentation included suboccipital pain in 26/ 37 patients and neck pain in 29/37 patients. 22 patients had presented with myelopathy ( Ranawat grade II or III A). The preoperative imaging included Plain X Rays, CT scans and MRI scans. All patients underwent C1/ C2 transarticular screws ( Stealth guided) except 4 patients in which an aberrant course of the vertebral artery was identified. Outcome measures: Functional outcome, Complications, Postoperative Neurological Status, Neck Disability index, Myelopathy disability index. Results: 1 patient had died at 12 month followup. Neck pain improved in 22( 75%) of patients by > 5 points on the VAS. Suboccipital pain had improved in all patients. 17 patients (80%) improved following operation on the Ranawat Grading, 2 patient were worse and 3 patients remained the same. > 70% patients reported improvement in neck disability index and > 50% patients reported improvement in myelopathy disability index. Conclusions: C1/ C2 Transarticular fixation with spinal navigation is a safe technique for treating atlantoaxial instability in patients with Rheumatoid Arthritis. This study demonstrates improvement in all domains including neck disability, myelopathy scores and functional outcome

Aims: To examine whether functional radiography and functional magnetic resonance imaging (MRI) are equal to detect the extent of unstabile anterior atlantoaxial subluxation (aAAS) in rheumatic patients. Methods: The series consisted of 23 patients with unstable aAAS (diagnosed by functional radiography) examined by functional MRI because of a neck symptom. Twenty-two patients had rheumatoid arthritis and one had juvenile idiopathic arthritis. aAAS was diagnosed if the anterior atlanto-axial diameter (AAD) was > 3 mm and was considered unstable if the AAD differed > 2 mm between flexion and extension radiographs. The AAD was measured from radiographs (flexion and extension) and MRI images (flexion and neutral). Results: The extent of aAAS during flexion measured by radiography was greater than that found by MRI in all our 23 cases [the mean difference was 3 mm (95% CI: 2 to 4)]. In 4 patients (17%) MRI could not find aAAS. The difference between the AAD measurements during flexion by these two methods was substantial (i.e. , ≥ 4 mm) in 9 cases (39%). Severe aAAS (≥ 9 mm) was seen in 15 patients (65%) by functional radiography and in 4 (17%) by functional MRI. Conclusions: The magnitude of aAAS was often substantially smaller in functional MRI than in functional radiography. Thus one cannot rely on functional MRI alone; functional radiographs are needed to show the size of unstable aAAS

Aims

To determine the normal values and usefulness of the C1/4 space available for spinal cord (SAC) ratio and C1 inclination angle, which are new radiological parameters for assessing atlantoaxial instability in children with Down syndrome.

The purpose of this study is the biomechanical comparison of five C1 – C2 posterior arthrodesis techniques. Ten adult human cadaveric upper cervical spine specimens were sectioned at the C3 level. The occiput and C3 vertebra were potted in PMMA. The specimens were tested intact; after destabilizing with odontoid transection and sectioning of the transverse and capsular ligaments; and after stabilization with Brooks-Jenkins cable fixation, Brooks-Jenkins with unilateral transarticular screw, Gallie posterior wire construct with unilateral transarticular screw, Brooks-Jenkins with bilateral screws, and Gallie with bilateral screws. Data were analysed with special attention paid to the motion at C1 – C2. The neutral zone (NZ) and range of motion (ROM) were measured in the main plane of each motion, as well as in coupled planes. In flexion / extension and lateral bending, the ROM and NZ increased significantly in the injured specimens as compared to the intact (p< 0.0001).

In axial torsion, there was no significant difference between the intact and injured spines at C1 – C2 level. In the different fixation systems, the ROM and NZ were significantly lower than in injured and intact spines in all motions (p< 0.01), except the lateral bending in intact spine. Among the 5 instrumentations, the NZ and ROM in flexion / extension for the Gallie construct with one screw were significantly higher than for the Brooks-Jenkins construct with one or two screws (p< 0.05). In axial torsion, the Gallie construct with one screw displayed a larger NZ and ROM than any of the other four constructs (p< 0.05).

Traumatic rotatory atlanto-axial dislocation and subluxations are rare injuries. The diagnosis is often missed or delayed because of subtle clinical signs. Head tilt makes the interpretation of plain radiographs difficult. Delayed diagnosis often results in chronic instability necessitating surgical stabilization. A hitherto undescribed clinical sign was evaluated which should lead to increased awareness and avoid delay in the diagnosis.

Why a new clinical sign?

Easily missed injury

Methods: This study was carried out between 1997 to 2003. The test was applied to 59 patients presenting in Accident and Emergency. All this patients had head tilt even after the application of a hard cervical collar. All the 59 patients had CT scans to confirm or exclude the diagnosis of Rotatory atlanto axial dislocation/subluxation.

Results: The new clinical sign was found to be positive in all the fourteen patients with atlanto- axial rotatory dislocations/subluxations which was confirmed by CT scan. The test was also found to be positive in 5 patients with unilateral facet joint dislocation. The sensivity of the test in our study was 100%. The specificity was 89%, positive predictive value 0.73, negative predictive value 0.9 (90%).

Conclusion: This new clinical sign may help in early recognition of the injury and also act as an effective screen to indicate which patient needs a CT scan to confirm the diagnosis. This can also be applied in places where the CT scan facilities are not readily available especially in the developing nations.

Introduction We review our experience with the use of plate and screw (C1 lateral mass and C2 pedicle) method of fixation in the treatment of 300 patients with disorders of the craniovertebral junction during a 17-year period at our center. We previously described this method of fixation in 1994. Methods Between 1988 and 2004, 250 patients with atlantoaxial instability were treated with the use of a plate and screw method of fixation at our institution. The various aetiologies of atlantoaxial instability were congenital, trauma and rheumatoid arthritis. All patients had mobile, completely reducible atlantoaxial subluxation. The male: female ratio was 3:1. C1 lateral mass screw and C2 pedicle screw were anchored to a plate bilaterally. For 3 months postoperatively, a hard cervical collar was used. The mean follow-up period was 42 months (range, 4 mo–17 yr). Recently, we have modified the technique by distracting the lateral facet joints, placing a cage bilaterally and then performing the lateral mass fixation for a subgroup of 50 patients with either fixed atlantoaxial joint subluxation or basilar invagination. Results Three patients died in the postoperative phase. Successful stabilization of the atlantoaxial region was documented with dynamic radiography in the other patients. In one patient, one screw was found to be broken 18 months after surgery; however, firm bony fusion was documented in this patient. There were no neurological, vascular, or infective complications. Discussion Segmental fixation of lateral masses with plate and screw method of fixation with the use of intra-articular bone grafts in patients with atlantoaxial instability yielded a 100% fusion rate with a low incidence of complications. Direct application of screws into the thick and large cortico-cancellous lateral masses of atlas and axis provides a biomechanically strong fixation of the region

Introduction: The efficacy and complications of the transarticular screw procedure have been reported by many authors. However, few have reported this procedure for child younger than 10 years old. We have treated two children for atlantoaxial subluxation with transarticular screws, using a soft collar without a halo-vest, and have achieved bone union in good reduced position. Methods/results. Case 1: a 5-year-old boy with mental retardation and cerebellar infarction due to an insufficiency of the vertebral artery resulting in severe atlantoaxial instability. He presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum. He has been treated with transarticular screw and iliac bone graft by Brooks procedure. Case 2: an 8-year-old boy with congenital spondyloepiphyseal dysplasia and a right valgus knee. He, too, presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum, and has been treated with transarticular screw and iliac bone graft by Brooks procedure. In both cases, we used two half-thread cortical screws with a diameter of 2.7mm and a length of 30mm for the transarticular screw procedure. Discussion/conclusion: Rigid external fixation was obtained by Halo-vest. This method, however, would be expected to cause mental stress for the child patient and the family. More rigid internal fixation would be required to resolve this problem. More rigid internal fixation can be obtained with the transarticular screw, and postoperative orthosis can be performed easily, without the need for a Halo-vest

Traumatic atlanto-occipital dislocation in adults is usually fatal and survival without neurological deficit is rare. The surgical management of those who do survive is difficult and controversial. Most authorities recommend posterior occipitoaxial fusion, but this compromises cervical rotation. We describe a case in which a patient with a traumatic atlanto-occipital disruption but no neurological deficit was treated by atlanto-occipital fusion using a new technique consisting of cancellous bone autografting supported by an occipital plate linked by rods to lateral mass screws in the atlas. The technique is described in detail. At one year the neck was stable, radiological fusion had been achieved, and atlantoaxial rotation preserved. The rationale behind this approach is discussed and the relevant literature reviewed. We recommend the technique for injuries of this type

Introduction and Aims: Odontoid fractures are quite common in the elderly following minor falls. As there are a few articulations in the upper cervical spine, degeneration in any one particular joint may affect the biomechanics of loading of the upper cervical spine. We aimed to analyse the pattern and relationship of odontoid fractures to the upper cervical spine osteoarthritis in the elderly. Method: Between July 1999 and March 2003, 185 patients had CT scan of the cervical spine for cervical spine injuries. Twenty-three out of 47 patients over the age of 70 years had odontoid fractures. The CT scan pictures of these patients were studied to analyse the type of fracture and its displacement, the severity of osteoarthritis in each articulation in the upper cervical spine, namely lateral atlantoaxial, atlantooccipital, atlantoodontoid and subaxial facetal joints, evaluation of osteopenia in the dens-body junction and in the body and odontoid process of the axis, and calcification of the ligaments. Results: Twenty-one of the 23 patients had Type II odontoid fracture with posterior displacement in seven (33.3%) and posterior angulation in nine (42.8%) patients. In these patients with Type II dens fracture, the atlantodens interval was obliterated in 19 (90.48%) patients, with only two of them (9.52%) having lateral atlantoaxial osteoarthritis. Conclusion: Type II fracture is the commonest odontoid fracture in the elderly. Posterior displacement of the fracture is common in elderly, unlike the younger population. There is a significant relationship between the upper cervical spine osteoarthritis, apart from osteopenia, to the incidence of Type II odontoid fractures. Significant atlantoodontoid osteoarthritis in the presence of normal lateral atlantoaxial joints increases the risk of sustaining Type II odontoid fracture