Internal reduction established by occiput-C2 pedicle polyaxial screw stabilization in pediatric atlantoaxial rotatory fixation

Atlantoaxial rotatory fixation is an uncommon disorder of childhood, which can be treated conservatively when diagnosed early. Although spontaneous correction occasionally occurs, most of the patients usually benefit from collar or traction therapies. If there is no intervention or if all external therapeutic modalities fail, the deformity may become chronic and irreducible. In such rare cases, surgical correction and stabilization are needed to prevent future head and neck deformity or facial asymmetry. In this report we describe a novel surgical technique used in a pediatric case presenting with delayed type 2 atlantoaxial rotatory fixation, in whom all external reduction methods had failed. The patient's deformity was treated by occiput-C2 pedicle polyaxial screw stabilization. This technique is effective for reducing the atlantoaxial fixation in children.

AtlantoAxial Rotatory Fixation: Part 3—A Prospective Study of the Clinical Manifestation, Diagnosis, Management, and Outcome of Children with AlantoAxial Rotatory Fixation

OBJECTIVE:

This is a prospective study of the clinical manifestations, diagnostic motion analysis, management, and outcome of children with atlantoaxial rotatory fixation (AARF).

METHODS:

Fifty children presenting with painful torticollis were subjected to the three-head positions diagnostic computed tomographic scanning protocol described in Part II of our AARF study. Twenty-nine children qualified as having AARF (8 Type I, 11 Type II, and 10 Type III), and six children were classified in the diagnostic gray zone (DGZ). The AARF patients were given either halter or calipers traction depending on the type and chronicity of pretreatment delay. Upon reduction, patients were immobilized with either a cervicothoracic brace or a halo. Recurrence of AARF on halo and patients whose deformity was not reducible were given posterior C1C2 fusion at the best achievable alignment. The difficulty and results of treatment were measured according to the following: duration of traction, number of reduction slippage, percent not reducible by traction, percent needing halo, percent needing fusion, total duration of treatment, total number of treatment procedures, and percent who lost normal C1C2 dynamics. Results were compared between groups stratified by AARF types, by chronicity of pretreatment delay (acute ≪ 1 mo, subacute = 1–3 mo, chronic ≥ 3 mo) and by the presence or absence of recurrence (recurrent AARF defined as having two or more slippages). DGZ patients were treated with only comfort measures for 2 weeks and then restudied. Only those children with persistent symptoms and DGZ or worse motion dynamics were given traction and bracing.

RESULTS:

Neither age nor etiology significantly influenced the severity of AARF. There was only a slight tendency for children younger than 5 years, and for trauma, to associate with severe C1C2 interlock. Delay of treatment up to 11 months did not result in improvement of the neck restriction or in abatement of pain. In fact, there are strong suggestions that prolonged delay could lead to worsening of the rotatory dynamics: Type I AARF are highly correlated with delays longer than 3 months and Type III with delays less than 1 month. Also, four patients who had serial motion studies during the delay period showed clear worsening in the pathological stickiness in C1C2 rotation. In addition, chronic rotatory deformity led to progressive occiput −C1 separation or laxity teleologically to compensate for a skewed visual axis. The mean occiput −C1 separation angle for chronic patients was 31.2° versus 5° for acute patients and less than 3° for normal children. The difficulty and duration of treatment, the number of reslippage after reduction, the rate of irreducibility, the need for halo and fusion, and the percentile of patients ultimately loosing normal C1C2 rotation were significantly greater with Type I patients than Type III patients, with Type II patients being intermediate. Likewise, chronic patients of all AARF types were much worse in all parameters than acute patients; subacute patients were closer to chronic patients in complexity and outcome. Severity and chronicity exerted independent effects on outcome, and the worse identifiable subgroup were the chronic Type I patients versus the best subgroup of acute Type III patients.

Thirteen patients developed recurrent AARF; they had much worse prognosis in all aspects measured than nonrecurrent patients. Recurrence was adversely influenced by both the severity (type) and chronicity of AARF. Half of the DGZ patients resolved with analgesics, but two of six remained symptomatic and in DGZ dynamics, and one deteriorated to Type III AARF. Two of those three patients responded easily to traction and bracing, and one was lost to follow-up.

CONCLUSION:

Children with painful torticollis should be subjected to the three-position computed tomographic diagnostic protocol, not only to secure the diagnosis of AARF but also to grade the severity of the condition by virtue of the dynamic motion curve. Closed reduction with traction should be instituted immediately to avoid the serious consequences of chronic AARF. Proper typing and reckoning of the pretreatment delay are requisites for selecting treatment modalities. Recurrent dislocation and incomplete reduction should be treated with posterior C1C2 fusion in the best achievable alignment. Open reduction and halo immobilization to avoid permanent fixation can be tried with select cases.

Grisel's syndrome: a rare complication following adenoidectomy

Grisel's syndrome, defined as subluxation of the atlanto-axial joint, not associated with trauma or bone disease, is found primarily in children. There are few references to this syndrome in the ENT literature but it may occur in association with any condition that results in hyperaemia and pathological relaxation of the transverse ligament of the atlanto-axial joint. Several common otolaryngeal conditions have been associated with the syndrome: pharyngitis, adenotonsillitis, tonsillar abscess, cervical abscess, and otitis media. Moreover, the syndrome has been observed after numerous otolaryngologic procedures such as tonsillectomy, adenoidectomy and mastoidectomy. Non-traumatic subluxation of the atlanto-axial joint should be suspected in cases of persistent neck pain and stiffness. X-rays and computed tomography scans of the cervical spine can confirm the diagnosis. Early management, consisting of cervical immobilization and medical treatment, is considered the key factor for a satisfactory outcome. Inappropriate treatment may result in a permanent and painful neck deformity that may even require surgical fusion. Neurological complications have been reported in the literature, with outcome ranging from mild paresthesia, clonus, to quadriplegia or acute respiratory failure and death. The case is described of an 8-year-old boy who developed Grisel's syndrome following adenoidectomy. The pathogenesis, classification, diagnosis, and treatment of this condition are discussed.

Decreased Muscle Strength and Mobility of the Neck in Patients With Rheumatoid Arthritis and Atlantoaxial Disorders

OBJECTIVE

To compare neck muscle strength and mobility of the cervical spine in rheumatoid arthritis (RA) patients with and without atlantoaxial (AA) disorders (anterior atlantoaxial subluxation [AAS], AA impaction).

DESIGN

Clinical cross-sectional study.

SETTING

Outpatient rheumatology and rehabilitation clinics in a Finnish hospital.

PARTICIPANTS

Patients with RA (N=124; mean age +/- standard deviation, 62+/-12y [corrected]) on a waiting list for orthopedic surgery. Thirty (24%) patients presented with AA disorders (16 with anterior AAS, 8 with AA impaction, 6 with a combination of anterior AAS and AA impaction).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Neck function was measured by isometric neck strength and mobility tests, neck pain by a visual analog scale, erosion of the hands and feet by radiography, and the patients' function by the Health Assessment Questionnaire (HAQ).

RESULTS

Maximal neck muscle strength against flexion, extension, and rotation was lower in patients with AA disorders compared with the other patients in both women (P=.012) and men (P=.017). Mobility was lowest in the AA impaction group in all measured directions (P<.001). Peripheral erosive disease was more frequent in the group with AA disorders. They also had longer disease duration and were more disabled (HAQ) than the other patients.

CONCLUSIONS

Neck muscle strength is significantly decreased in patients with AA disorders. Mobility of the cervical spine is most limited in patients with AA impaction, but can be normal in cases with solitary anterior AAS.

Whiplash-associated disorders impairment rating: neck disability index score according to severity of MRI findings of ligaments and membranes in the upper cervical spine

The aim of this study was to explore whether reported pain and functional disability in whiplash-associated disorders (WAD) patients is associated with lesions to specific soft tissue structures in the upper cervical spine, as assessed by MRI. Pre-selected structures for MRI assessment included the alar ligaments, the transverse ligament, the tectorial and the posterior atlanto-occipital membranes. The questionnaire employed was a modification of the Oswestry Low Back Pain Index. It was comprised of ten single items related to pain and activity of daily living. Ninety-two whiplash patients and 30 control persons, randomly drawn, were included. WAD patients reported significantly more pain and functional disability than the controls, both for total score and each of the ten single items. In the WAD patients, MRI lesions to the alar ligaments showed the most consistent association to the reported pain and disability. Lesions to other structures often occurred in combination with lesions to the alar ligaments. Lesions to the transverse ligament and to the posterior atlanto-occipital membrane also appeared to be related to the NDI score, although the association was weaker than for the alar ligament. The disability score increased with increasing number of abnormal (grade 2-3) structures. These results indicate that symptoms and complaints among WAD patients can be linked with structural abnormalities in ligaments and membranes in the upper cervical spine, in particular the alar ligaments.

Ossification of the posterior atlantoaxial membrane and the transverse atlantal ligament

STUDY DESIGN

Case report.

OBJECTIVE

To report a case of ossification of the posterior atlantoaxial membrane (PAAM) and ossification of the transverse ligament of the atlas (TAL).

SUMMARY OF BACKGROUND DATA

Ossification of the PAAM and TAL are both very rare clinical entities. This is the first case involving ossification of both the PAAM and TAL with the development of cervical myelopathy.

METHODS

Patient's history, physical examination, radiographic evaluation, surgical treatment, and outcome are examined. Relevant literature is also reviewed.

RESULTS

The patient's neurological symptoms significantly improved after posterior decompressive surgery.

CONCLUSION

Ossification of various parts of the spinal ligament have been reported previously. Among them, ossification of both the PAAM and TAL has never been reported previously and is thus extremely rare. Surgical intervention improved the neurological impairment.

Cervical angina caused by atlantoaxial instability

Cervical angina is defined as a paroxysmal precordialgia that resembles true cardiac angina caused by cervical spondylosis. Cervical angina most commonly results from compression of the C7 ventral root. We present here a case of cervical angina caused by atlantoaxial instability. This case had marked atlantoaxial instability but no flexibility of the middle to lower levels of the cervical spine. Although there was mild C7 root compression on the radiologic findings, the chest pain was induced by neck motion, and the precordialgia disappeared after posterior atlantoaxial fusion without C7 root decompression. Therefore, we diagnosed this case as cervical angina caused by spinal cord compression at the C1-C2 level. It was speculated that a perturbation of the sympathetic nervous system or a hypofunction of the pain suppression pathway in the posterior horn of the spinal cord caused the pectoralgia. Although cervical angina is a rare disease, physicians should be aware of it; if there are no abnormal findings on cardiac examinations for angina pectoris, they should examine the cervical spine. Cervical angina due to atlantoaxial instability is one of the differential diagnoses of precordialgia.

Persistent fixed torticollis due to Atlanto-axial rotatory fixation: report of 4 pediatric cases

Atlanto-axial rotatory fixation (AARF) is a rare cause of childhood torticollis that may occur spontaneously or in association with trauma and upper respiratory infections. We describe the clinical findings, as well as the effectiveness of imaging in the diagnosis and the treatment of 4 children with AARF, in whom acute fixed non-dystonic torticollis was the presenting symptom. Onset of torticollis was spontaneous in Case 1, after general anesthesia for cholesteatoma surgery in Case 2, after a trauma in Case 3, and during hypersomnia in Case 4. Duration of torticollis prior to diagnosis was 3 months in the first two patients and 20 days in the other two. All the patients underwent cervical X-rays examinations, which were not contributory to the diagnosis, followed by CT, which demonstrated C1-C2 rotatory fixation. One patient had a spontaneous resolution; treatment with Gardner's tongs and soft collar permitted restoration of the normal alignment in the other 3 patients. AARF must be considered in all the patients with persistent painful torticollis.

Evaluation of flexion/extension of the upper cervical spine in patients with rheumatoid arthritis: an MRI study with a dedicated positioning device compared to conventional radiographs

PURPOSE

Using flexion/extension magnetic resonance imaging (MRI) with a dedicated positioning device, our purpose was to analyze pathologic cranio-vertebral joint anatomy and motion in patients with rheumatoid arthritis in comparison to normal patients, and to compare flexion/extension MRI with conventional radiographs (CRs) in patients with rheumatoid arthritis.

MATERIAL AND METHODS

The 31 patients with rheumatoid arthritis and 20 healthy subjects included in the study were imaged in an open MRI scanner during flexion/extension. A dedicated positioning device was used. Additionally, we compared flexion/extension MRI with CRs in patients with rheumatoid arthritis. In MRI, the orientation and segmental motion of C0, C1, and C2 were assessed and structure of the dens and amount of pannus tissue were observed. Configuration of the cerebrospinal fluid space and the cord was evaluated in each position. In both MRI and CRs, anterior atlanto-axial subluxation and vertical dislocation were assessed and sagittal diameter of the dural sac was measured.

RESULTS

In the neutral position, C1 of the patients was oriented in a more flexed position in relation to both C0 and C2 compared to that in healthy subjects. The patients had more extension in the upper cervical spine than did healthy subjects. In flexion, atlantoaxial subluxation was greater in CRs than in MRI. In MRI, the amount of vertical dislocation did not depend on position. In the patients, there was considerably more cord impingement in flexion than in other positions.

CONCLUSION

Evaluation of the rheumatoid cervical spine is optimized using MR images in the neutral, flexed, and extended positions. Measurements and relationships between structures should be compared in all positions. CRs with flexion-extension views are recommended as the first imaging method.

Biomechanical comparison of C1–2 posterior fixation techniques

Object. In a nondestructive, repeated-measures in vitro flexibility experiment, the authors compared the acute stability of C1–2 after placement of C-1 lateral mass and C-2 pars interarticularis (LC1—PC2) instrumentation with that of C1–2 transarticular screw fixation.

Methods. The effect of C-1 laminectomy and C1–2 interspinous cable/graft fixation on LC1—PC2 stability was studied. Screw pullout strengths were also compared. Seven human cadaveric occiput—C3 specimens were loaded nondestructively with pure moments while measuring nonconstrained atlantoaxial motion. Specimens were tested with graft alone, LC1—PC2 alone, LC1—PC2 combined with C-1 laminectomy, and graft-augmented LC1—PC2. Interspinous cable/graft fixation significantly enhanced LC1—PC2 stability during extension. After C-1 laminectomy, the LC1—PC2 construct allowed increased motion during flexion and extension. There was no significant difference in lax zone or range of motion between LC1—PC2 fixation and transarticular screw fixation, but graft-assisted transarticular screws yielded a significantly smaller stiff zone during extension. The difference in pullout resistance between C-1 lateral mass screws and C-2 pars interarticularis screws was insignificant. The LC1—PC2 region restricted motion to within the normal range during all loading modes. Atlantal laminectomy reduced LC1—PC2 stability during flexion and extension.

Conclusions. The instrumentation-augmented LC1—PC2 construct performed biomechanically similarly to the C1–2 transarticular screw fixation. The LC1—PC2 construct resisted flexion, lateral bending, and axial rotation well. The weakness of the LC1—PC2 fixation in resisting extension can be overcome by adding an interspinous graft to the construct.

Prevalence of C1/C2 involvement in Czech rheumatoid arthritis patients, correlation of pain intensity, and distance of ventral subluxation

The aim of this study was to determine the prevalence of C1/C2 involvement in rheumatoid arthritis (RA) in Czech patients and to identify typical pain symptoms and their relationship to radiologic findings at the C1/C2 level. Four hundred patients with RA were selected randomly and examined by plain X-ray. Cervical spine involvement was found in 45.8% of these patients. Cervicocranial syndrome was the most common symptom of any spine involvement at the C1/C2 level and was present in 54.6%. Cervicocranial syndrome was typical for ventral subluxation 3-6 mm and was found in 52.9%. The distance of 8 mm or more was associated with mild pain. The pain intensity at the C1/C2 level decreased with increasing distance of ventral atlantoaxial subluxation (P < 0.0001).

Novel treatment of basilar invagination resulting from an untreated C-1 fracture associated with transverse ligament avulsion

✓ The authors describe the case of a traumatic C-1 ring fracture and transverse ligament injury in an otherwise healthy adult woman; the lesion was essentially untreated for 3 months and resulted in basilar invagination. On presentation 3 months postinjury, the patient complained of severe increasing suboccipital pain and a grinding sensation in her upper neck. Axial computerized tomography (CT) scans revealed a C-1 ring fracture, basilar invagination with the dens abutting the clivus, and significant lateral splaying of the C-1 lateral masses. Flexion—extension radiography demonstrated abnormal motion at the atlantoaxial junction. A unique surgical technique was used to address simultaneously the C1–2 instability, the displaced C-1 fracture, and basilar invagination without having to perform occipital fixation. The authors believe that an understanding of the mechanism of the cranial settling in this case (further splaying of the C-1 lateral masses and downward migration of the occipital condyles) permitted full reduction of the deformity; this was accomplished by performing a horizontal reduction of the C-1 lateral masses, using direct C-1 lateral mass screws, a rod compressor, and a cross-link. Postoperative CT scanning confirmed the success of reduction. The results in this report highlight a rare but important complication of untreated C-1 fracture and ligament disruption, and the authors describe a novel treatment technique with which to restore vertical alignment and preserve occipital C-1 motion. A variation of this technique may also be used to treat Type II transverse ligament injuries associated with C-1 ring fractures as an alternative to halo immobilization.

Atlantoaxial rotatory fixation: Part 1--Biomechanics of normal rotation at the atlantoaxial joint in children

OBJECTIVE

Atlantoaxial rotatory fixation (AARF) remains a recondite entity loosely included under the panoply of cervical trauma. The difficulty in finding a precise definition and reliable diagnostic criteria for AARF has been chiefly because of a lack of normative biomechanical data for C1-C2 rotation. As Part 1 and foundation of a comprehensive undertaking to define the biomechanics, mechanism, diagnosis, classification, and management of AARF, the present study focuses on the dynamic behavior of C1 and C2 during normal voluntary head rotation in children.

METHODS

Twenty-one normal children 3 to 11.5 years old underwent computed tomographic examinations from the lower clivus to the base of C3 in various head positions during axial rotation. The angles made by C1, C2, and the occiput with the vertical 0 degrees were recorded, and from these, the separation angles between C1 and C2 (C1-C2 degrees) were calculated for each head position (represented by the C1 angle) studied. In 18 children, the range of rotation was between 90 and -90 degrees, i.e., with the head making a full 180-degree turn from one side to the other. In 3 children, the head was first turned from 0 to 90 degrees and then back from 90 to 0 degrees, making only a half turn. All separation angles (C1-C2 degrees) were then plotted against the corresponding C1 angle to create a motion curve, which, in essence, describes the interaction between C1 and C2 through the full range of head positions. In the 18 children with full turns, both individual motion curves and a composite motion curve comprising all data were constructed.

RESULTS

There is a high degree of concordance for rotational behavior of C1 and C2 in the 18 subjects undergoing full turn. C1 always crosses C2 at or near 0 degrees, the null point of full rotation. The predictable relationship between C1 and C2 is depicted by three distinct regions on the composite motion curve: when C1 rotates from 0 to 23 degrees, it moves alone, with C2 remaining stationary at approximately 0 degrees (the single-motion phase). When C1 rotates from 24 to 65 degrees, C1 and C2 move together, but C1 always moves at a faster rate (the double-motion phase), C2 being pulled by yoking ligaments. From 65 degrees onward, C1 and C2 move in exact unison (the unison-motion phase) with a fixed, maximum separation angle of approximately 43 degrees, head rotation being carried exclusively by the subaxial segments. In the 3 children with half turn, the forward rotation curve and the reverse rotation curve are almost superimposable, suggesting that the "yoking" between C1 and C2 is a result of more than just tensing and relaxing of ligaments but probably also to a mutual dragging by irregular bony surfaces between the two bones.

CONCLUSION

C1 and C2 in children move in a predictable manner during axial head rotation, with a high degree of concordance among subjects and a relatively narrow variance from the mean. The composite motion curve can thus be used as a touchstone against which may be judged all manners of pathological interlock or "stickiness" between C1 and C2 in rotation that could be defined as AARF.

Concomitant alar and apical ligament avulsion in atlanto-axial rotatory fixation. Case report and review of the literature

The authors report a case of Fielding type II acute atlanto-axial rotatory fixation (AARF). The CT scan with coronal reconstruction showed an avulsion of the apical and right alar ligament. These findings are exceptionally reported in the literature, especially concerning the apical ligament which might be a stabiliser in flexion and extension of the occipitocervical joint.

Atlantoaxial instability in neck retraction and protrusion positions in patients with rheumatoid arthritis

STUDY DESIGN

Radiographic analysis of the upper cervical spine was performed in patients with rheumatoid arthritis who had C1-C2 instability.

OBJECTIVE

To assess whether neck retraction or neck protrusion movements can cause C1-C2 subluxation in patients with C1-C2 instability.

SUMMARY OF BACKGROUND DATA

Cervical protrusion is the position where the head is maximally translated anteriorly with zero sagittal rotation, and this position has been shown to produce maximal C1-C2 extension. In contrast, cervical retraction is the position where the head is maximally translated posteriorly, and this position produces maximal C1-C2 flexion. To date, there have been no studies evaluating the effects of these two positions on C1-C2 status in patients with C1-C2 instability.

METHODS

Twenty-four patients with rheumatoid arthritis who showed an atlantodental interval of at least 5 mm during neck flexion were evaluated in this study. These patients were instructed to actively hold the neck in protrusion and retraction positions, as well as in flexion and extension positions. Lateral cervical radiographs were taken to measure the C1-C2 angle and the atlantodental interval in the sagittal plane in each position.

RESULTS

Retraction produced both maximal C1-C2 flexion and anterior C1-C2 subluxation, of a degree just the same as that produced by cervical flexion. Protrusion reversely produced maximal C1-C2 extension. However, 9 of 24 patients exhibited C1-C2 subluxation even in this protrusion position, in marked contrast to the cervical extension position in which only 2 of 24 patients showed C1-C2 subluxation. The patients who showed C1-C2 subluxation in the protrusion position tended to have more severe C1-C2 instability and less capacity for C1-C2 extension than the other patients who achieved a reduction of C1-C2 in the protrusion position.

CONCLUSION

In patients with C1-C2 instability, not only cervical flexion but also cervical retraction constantly led to both maximal C1-C2 flexion and subluxation. In some patients with severe C1-C2 instability, protrusion also resulted in C1-C2 subluxation, even though the C1-C2 was maximally extended.

Atlantoaxial rotatory subluxation with ankylosis in an 11-year-old girl: a case report

STUDY DESIGN

Report of an 11-year-old girl with a left atlantoaxial rotatory subluxation and ankylosis found 20 months after she sustained a cervical injury.

OBJECTIVE

To describe the radiographic characteristics of this rare deformity assessed with a combination of spiral CT scan with multiplanar three-dimensional reformations and functional CT scan.

SUMMARY OF BACKGROUND DATA

Atlantoaxial rotatory subluxation is a well-known condition, but its association with lateral C1-C2 ankylosis has not been reported to our knowledge.

METHODS

For a complete assessment of the dislocation, a combined morphologic volumetric and functional CT study was performed.

RESULTS

Spiral CT showed an atlantoaxial rotatory subluxation with lateral C1-C2 ankylosis. CT study also demonstrated a lateral C1-C2 subluxation and an ipsilateral occipitoatlantal subluxation. Cervical MRI showed no spinal cord compression despite the seriousness of the dislocation process.

CONCLUSIONS

Whereas "classic" spiral study with multiplanar and three-dimensional reformations allows precise assessment of relationships between the upper cervical vertebrae, as well as bony changes, a functional CT study is essential for cervical biomechanic assessment of rotational instabilities of the craniovertebral junction and upper cervical spine.

Ossification of the transverse atlantal ligament associated with fluorosis: a report of two cases and review of the literature

STUDY DESIGN

Two cases of ossification of the transverse atlantal ligament (OTAL) are reported, and the literature is reviewed.

OBJECTIVE

To report two cases of OTAL, which share fluorosis as a possible etiologic link.

SUMMARY OF BACKGROUND DATA

OTAL, a rare phenomenon, may cause upper cervical canal stenosis and spastic quadriparesis. However, the incidence, etiology, and the best therapeutic options are currently unclear.

METHODS

Two cases are reported. Included are pertinent history, physical examination, radiographic evaluation, nonsurgical interventions, and outcomes. The available literature is also reviewed.

RESULTS

On systemic examination, these two cases were found to have ossification of many ligaments and interosseous membranes, i.e., the atlantal transverse ligament, posterior longitudinal ligament, and interosseous membranes of ribs, forearm, and leg. These findings were coupled with a history of high fluoride intake and dental fluorosis; the diagnosis of fluorosis was made. After 2 weeks of treatment with halo ring traction, and protection and stabilization with a hard cervical collar, the clinical symptoms significantly improved.

CONCLUSION

The incidence of OTAL may be not as rare as has been thought. Although the complete etiology of OTAL is not known, fluorosis may be one of the etiologic factors related to OTAL, as well as the ossification of other ligaments and interosseous membranes. Nonsurgical treatment may be safe and effective.

Treatment of atlantoaxial instability in pediatric patients

The atlantoaxial region has been extensively described as a spinal segment especially prone to injury in children. In this clinical review, the authors evaluate and summarize the management of 23 pediatric cases of atlantoaxial instability treated between March 1990 and October 2002. Four broad categories of atlantoaxial problems were observed-atlantoaxial rotatory subluxation in six patients, anterior-posterior atlantoaxial instability caused by ligamentous injury or congenital ligamentous laxity (10 patients), atlantoaxial fracture with or without dislocation (five patients), and atlantooccipital dislocation (two patients). Most cases (60.9%) were treated without surgical intervention, resulting in excellent outcomes; however, 21.7% of cases were treated with a cervical halo (mean patient age 72.6 months) alone for 3 months. Various techniques of surgical stabilization including transarticular screws with sublaminar wiring, transoral decompression with posterior plating, and laminectomy with Steinmann pin occipital-cervical fusion were used with good results. Both patients with atlantooccipital dislocation underwent immediate Locksley occipital-cervical fusion, with marked neurological improvement. Individualized case management must be based on clinical presentation, with internal fixation being the last resort.

Atlantoaxial rotatory fixation secondary to tuberculosis of occiput: a case report

STUDY DESIGN

A case of nontraumatic rotatory fixation of the atlantoaxial joint associated with tuberculosis of the occipital bone in an adult.

OBJECTIVES

To report a rare case of atlantoaxial rotatory subluxation associated with tuberculosis of the occipital bone in an adult and to discuss the mechanism of fixation.

SUMMARY OF THE BACKGROUND DATA

Atlantoaxial rotatory fixation in adults is rare and has been reported due to variety of causes. To the authors' best knowledge no case has been reported secondary to tuberculosis of the skull bone.

METHODS

A 20-year-old male presented with resistant torticollis with a duration of 5 months.

RESULTS

The patient had type 1 atlantoaxial rotatory fixation secondary to tuberculosis of the occipital bone. The subluxation was partially reduced by conservative means, and healing of the occiput lesion was achieved. Thereafter, the patient had no restriction of cervical spine motion and had no reoccurrence of subluxation at a follow-up of one and a half years.

CONCLUSIONS

Effusion in the atlantoaxial joint secondary to infection in the occiput due to close proximity with the joint led to the laxity of ligaments and contributed to the subluxation.

Failure of posterior titanium atlantoaxial cable fixation

BACKGROUND CONTEXT

The operative treatment of rotatory atlantoaxial instability remains controversial. The use of cable fixation has largely replaced the use of wire for interlaminar fixation. Although cable fixation offers biomechanical advantages over wire fixation, it is still at risk of fatigue failure. The authors were unable to locate any published reports of fatigue failure of titanium cables in the fixation of atlantoaxial instability.

PURPOSE

The purpose of this case study is to describe an unusual case of fatigue failure of a titanium cable used to aid in atlantoaxial fusion for the treatment of rotatory atlantoaxial instability.

STUDY DESIGN

Case study.

METHODS

We reviewed the medical records and X-rays of a patient with rotatory atlantoaxial instability treated with posterior C1-C2 fusion and atlantoaxial fixation with a titanium multistranded cable, who developed fracture of the cable and migration of the cable into the spinal canal.

RESULTS

The patient was revised with removal of the broken cable, repair of the pseudarthrosis and fixation with atlantoaxial screws.

CONCLUSION

Interlaminar fixation with cables or wires is at risk for failure with potential migration of the wire or cable into the spinal canal. The authors found that failure of the cables or wire can be salvaged with application of transarticular screws.