Atlantoaxial Instability In Children Research Articles

Comparative characteristics of cervical sagittal balance parameters and atlantoaxial instability criteria in normal and Down syndrome children

BACKGROUND: Sagittal balance of the spine has received considerable development in recent years. However, most studies focused on the assessment of vertebral–pelvic parameters. The cervical spine has long received insufficient attention from researchers, but this trend has been changing. The study of cervical sagittal balance in children with Down syndrome is beneficial in approaching the preconditions of atlantoaxial instability. AIM: To perform a comparative analysis of cervical sagittal balance parameters and atlantoaxial instability criteria in normal and Down syndrome children. MATERIALS AND METHODS: Radiographs of the cervical spine in the neutral position in lateral projection and postural radiographs of 110 pediatric patients were analyzed retrospectively. The patients were divided into two groups: group 1 (normal), 60 children aged 4–17 years without spinal pathology, and group 2 (Down syndrome), 50 children aged 4–17 years with Down syndrome. The parameters of cervical sagittal balance (Oc-C2, Oc-C7, C1-C2, C2-C7, C2-C7H, C7S, Th1S, TIA, NT) and criteria for atlantoaxial instability (Nakamura angle, ADI, SAC-C1, SAC-C1/SAC-C4) were obtained, and data was statistically analyzed. RESULTS: Significant differences in the parameters C7S, Th1S, and TIA increased in children with Down syndrome. These parameters are involved in cervical lordosis; however, no significant differences in cervical lordosis angles were found. Furthermore, significant differences were noted in the criteria of atlantoaxial instability ADI, SAC-C1, and SAC-C1/SAC-C4 toward their decreasing in children with Down syndrome. CONCLUSION: In patients with Down syndrome, the indices of cervical lordosis are statistically greater than those in normal children. Moreover, the parameters of cervical lordosis in patients with Down syndrome do not differ from those in normal children. Therefore, during flexion, subcompensation of the cervical spine is observed in children with Down syndrome. Given the statistically smaller indicators ADI, SAC-C1, SAC-C1/SAC-C4, low neck muscle tone, and ligamentous hypermobility, these abnormalities can be considered as congenital predisposition factors for atlantoaxial instability in children with Down syndrome.

Atlantoaxial Instability in Children, 26 Years of Experience

Study Design: Retrospective case study.
 Objective: To determine the history, clinical and imaging signs, diagnosis, treatment and clinical follow-up.
 Summary of Background Data: The cranio vertebral junction (CVJ) is a complex transitional area between the skull, the upper cervical spine, the brain and the upper cervical cord. It concerns all ages. Instability can be the result of congenital malformations or traumatic injury.
 Methods: It is a retrospective study of patients files in department of paediatricneurosurgery and the department of pediatric orthopedic of Marseille, during 26 years , Between 16th October 1981 and 16th June 2007 In each medical record, we determined identity, circumstances of instability discovery, clinical and paraclinical signs, diagnosis, therapeutic protocol and patient's outcome after treatment.
 The inclusion criteria were the medical records with complete information regarding the patients, who were treated for atlantoaxial instability (AAI). Patients presenting clinical instability with incomplete files, have been excluded.
 Results: In our retrospective study, 22 children have been treated for AAI, with 10 boys (45%) and 12 girls (55%), aged 5 to 17 years old, mean age was 10.
 the main circumstance of lesion was accident 45,5%, sport accident 27,3%, road accident 18,2%), the others circumstances are 55,5%.
 The past history included : congenital malformation in 18,2% (Down’s syndrome, Klippel- Fiel’s syndrome, cardiac malformation), sport accident(9,0%), neurological deficit (13,7%), cervical trauma already treated(4,5%), learning deficit (4,5%), and plagiocephaly (4,5%); for 45,6%, there was no evidence etiology.
 The clinical signs were quadriparesis (31,9%), quadriplegia (13,6%), torticoli (9,1%), quadriplegia and priapism (4,5%), headache and dizziness (4,5%), abnormal head position attitude (4,5%). Clinical exam was normal for 31,9%.
 Standard X-ray was performed for 50,0%, CT scan for 50,0% and MRI for 40,8%.
 These paraclinical examination showed that AAI were traumatic in 59,1% (luxation 36,4%, odontoïdum fracture 13,7%, C1C2 dislocation 4,5 %, C2 arch, articular fracture and pseudoarthrosis 4,5%), congenital malformation in 40,9%.
 The orthopedic treatment was used for 13,5% of the patients and surgical treatment was used for 86,5% of the patients (posterior approach72,8 %, anterior approach 9,2%, anterior and posterior approach 4,5%).
 Complications were observed in 33% of the patients (consisted of infections 14%, Medulla oblongata compression 5%, basilar impression)
 72% of the patients recovered without sequela after 15years of follow up, 28% had a neurological deficit during the same time .13% conserved their deficit 5 years after treatment.
 Conclusion: In many cases, AAI is an insidious affliction in many cases. A neurological deficit is a sinister presentation often leading to significant sequela even after treatment.

Atlanto-axial instability in children with Down syndrome

Atlanto-axial instability in children with Down syndrome

Complications of Posterior Fusion for Atlantoaxial Instability in Children With Down Syndrome.

ObjectiveTo clarify the complications of posterior fusion for atlantoaxial instability (AAI) in children with Down syndrome and to discuss the significance of surgical intervention.MethodsTwenty pediatric patients with Down syndrome underwent posterior fusion for AAI between February 2000 and September 2018 (age, 6.1±1.9 years). C1–2 or C1–3 fusion and occipitocervical fusion were performed in 14 and 6 patients, respectively. The past medical history, operation time, estimated blood loss (EBL), duration of Halo vest immobilization, postoperative follow-up period, and intra- and perioperative complications were examined. ResultsThe operation time was 257.9±55.6 minutes, and the EBL was 101.6±77.9 mL. Complications related to the operation occurred in 6 patients (30.0%). They included 1 major complication (5.0%): hydrocephalus at 3 months postoperatively, possibly related to an intraoperative dural tear. Other surgery-related complications included 3 cases of superficial infections, 1 case of bone graft donor site deep infection, 1 case of C2 pedicle fracture, 1 case of Halo ring dislocation, 1 case of pseudoarthrosis that required revision surgery, and 1 case of temporary neurological deficit after Halo removal at 2 months postoperatively. Complications unrelated to the operation included 2 cases of respiratory infections and 1 case of implant loosening due to a fall at 9 months postoperatively. ConclusionThe complication rate of upper cervical fusion in patients with Down syndrome remained high; however, major complications decreased substantially. Improved intra- and perioperative management facilitates successful surgical intervention for upper cervical instability in pediatric patients with Down syndrome.

Two novel parameters to evaluate the influence of the age and gender on the anatomic relationship of the atlas and axis in children no more than 8years old: imaging study.

Because of the complex cervical vertebral embryology and some normal variations, the atlantoadental interval (ADI) was not suitable for the evaluation of the anatomic relationship between the atlas and axial in children less than 2years old. And the influence of the age and gender on the anatomic relationship between atlas and axial in children was still unclear. Two novel parameters, atlas-axis anteroposterior distance (AAAD) and atlas-axis lateral distance (AALD), were invented to evaluate the anatomic relationship between the atlas and axis in the children no more than 8years old with different age and gender. Cross-sectional computed tomography (CT) scans of the atlantoaxial joint for 140 randomly selected pediatric patients no more than 8years old were analyzed. On the ideal CT reconstruction images, AAAD, AALD, atlantoaxial lateral bending angle (AALB), and atlantoaxial rotation angle (AARA) were measured. There was no statistically significant difference between the mean AAAD in different age and gender groups. The 99% confidence interval for AAAD was 7.12-7.82mm. There was no significant correlation between AAAD and AALB/AARA and AALD and AALB/AARA. The AAAD was less than 7.12mm or much than 7.82mm that suggested a possible instability in the atlantoaxial joint and could help the diagnosis of the atlantoaxial instability in children no more than 8years old. There was no difference between the mean AAAD of pediatric patients no more than 8years old in different age and gender groups.

Feasibility and outcome of stand-alone trans-articular screw fixation in atlantoaxial instability in children less than 8years of age.

To study the feasibility and outcome of stand-alone trans-articular screw (TAS) fixation for atlantoaxial instability (AAI) in children less than 8years of age. This prospective study was conducted between 2009 and 2014. Thirteen children suffering from AAI were operated for a TAS fixation. Feasibility of TAS fixation was assessed on CT scan and a screw diameter was chosen based on C2 isthmus diameter. Demographic data collected included the etiology for AAI, age, and sex. Intra-operative data recorded was the duration of surgery, blood loss, vertebral artery injury or any adverse event. Radiological evaluation included pre- and post-operative atlantodens interval (ADI) and space available for cord (SAC) and fusion was evaluated at 3, 6, 12 and 24months. Statistical analysis was done using SPSS software and statistical significance was set at p<0.05. The mean age of the final study group was 6.1±1.5years, with nine males and four females. Mean isthmus diameter on the left and right side was 3.3±0.3 and 3.2±0.2mm, respectively. Five patients had an isthmus diameter of <3.2mm and a 2.7mm Herbert screw was used in them and in nine patients, a CCS of 3.2mm was used. Mean pre- and post-op ADI and SAC improved from 5.5±0.8 to 3.1±0.1mm, respectively, and 9.8±2.8 to 14±0.6mm, respectively. Fusion was seen in all patients. Stand-alone TAS with morselized allograft is safe, feasible and successful in managing AAI in children below 8years of age. These slides can be retrieved under Electronic Supplementary Material.

New radiological parameters for the assessment of atlantoaxial instability in children with Down syndrome

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. We recruited 272 children with Down syndrome (including 14 who underwent surgical treatment), and 141 children in the control group. All were aged between two and 11 years. The C1/4 SAC ratio, C1 inclination angle, atlas-dens interval (ADI), and SAC were measured in those with Down syndrome, and the C1/4 SAC ratio and C1 inclination angle were measured in the control group. The mean C1/4 SAC ratio in those requiring surgery with Down syndrome, those with Down syndrome not requiring surgery and controls were 0.63 (standard deviation (sd) 0.1), 1.15 (sd0.13) and 1.29 (sd 0.14), respectively, and the mean C1 inclination angles were -3.1° (sd10.7°), 15.8° (sd 7.3) and 17.2° (sd 7.3), in these three groups, respectively. The mean ADI and SAC in those with Down syndrome requiring surgery and those with Down syndrome not requiring surgery were 9.8 mm (sd 2.8) and 4.3 mm (sd 1.0), and 11.1 mm (sd 2.6) and 18.5 mm (sd 2.4), respectively. The normal values of the C1/4 SAC ratio and the C1 inclination angle were found to be about 1.2° and 15º, respectively. Cite this article: Bone Joint J 2016;98-B:1704-10.

PREVALENCE OF ATLANTO-AXIAL INSTABILITY AND ITS ASSOCIATION WITH CLINICAL SIGNS IN CHILDREN WITH DOWN SYNDROME

Introduction: A change in the atlanto-axial alignment in children with Down syndrome may be associated with pain, neurological disorders, high spinal cord compression and sudden death. Objective : To determine the prevalence of atlanto-axial instability in children with Down syndrome and its association with the presence of signs and symptoms of atlanto-axial instability. Methods : A cross-sectional study evaluated 21 children with Down syndrome aged between 3 and 5 years. Children who had undergone cervical spine surgery or who had diseases not associated with this syndrome were excluded. Sex, age, ethnicity of the child and the presence of signs suggestive of atlanto-axial instability, as reported by caregivers, such as neck pain, difficulty walking, weakness in the lower limbs, fatigue, difficulty with balance, urinary and fecal incontinence and projectile vomiting were studied. Children underwent a cervical spine X-ray in the lateral view in three positions: neutral, flexion and extension. When the atlas-odontoid distance was equal to or greater than 4.5 mm, atlanto-axial instability was diagnosed. Results: The prevalence of atlanto-axial instability in the studied population was 9.5%. There was no significant association revealed in the chi-square test between the signs suggestive of atlanto-axial instability and the presence of atlanto-axial instability (p > 0.05). Conclusions : Atlanto-axial instability is possibly not associated with its suggestive signs.

Novel 2 radiographical measurements for atlantoaxial instability in children with Down syndrome.

A retrospective case-control study. To assess the usefulness and reproducibility of 2 novel safe and simple radiographical measurements for atlantoaxial instability in children with Down syndrome. In pediatric atlantoaxial instability, early diagnosis is important for improved outcomes because of poor postoperative recovery in progressed neurological symptoms. Conventional dynamic radiography of the cervical spine is associated with a potential risk of worsening neurological symptoms. We retrospectively reviewed the medical records of 50 patients (24 boys and 26 girls) with atlantoaxial instability associated with Down syndrome. Of the 50 children, 11 had undergone and 4 had been scheduled for surgery (surgical group). In this investigation, in addition to the atlas-dens interval (ADI) and space available for spinal cord (SAC), we measured C1 inclination angle and C1/4 SAC ratio on lateral radiographs of the cervical spine in the neutral position. To assess the diagnostic abilities of these indices to determine indication for surgery, receiver operating characteristic analysis of each index was performed, and their diagnostic abilities were compared using the area under the receiver operating characteristic curve. Moreover, we assessed reproducibility of our 2 proposed indices. The discriminatory abilities of C1/4 SAC ratio (area under the receiver operating characteristic curve, 1.00) and C1 inclination angle (0.91) were comparable with those of ADI (0.98) and SAC (0.95). For the interobserver and intraobserver reliability of the novel indices, the correlation coefficients were in the range from 0.88 to 0.99. Correlation was observed between the ADI and C1/4 SAC ratio (r = 0.507, P < 0.01) and between the ADI and C1 inclination angle (r = 0.407, P < 0.01). The diagnostic abilities of the 2 novel radiographical measurements were comparable with those of ADI and SAC. Moreover, these novel measurements can be obtained safely on lateral radiographs of the cervical spine in the neutral position. 4.

Acquired Atlantoaxial Instability in Children With Spastic Cerebral Palsy

The development of nontraumatic atlantoaxial instability in children with spastic cerebral palsy has not been reported. The authors present three patients with severe spastic quadriplegia who developed C1-C2 instability and cervical myelopathy at mean age 12.6 years. These patients demonstrated a similar clinical picture with symptoms attributed to cervical myelopathy in varied severity including apneic episodes, opisthotonus, alteration in muscle tone, torticollis, respiratory problems, hyperreflexia, and bradycardia. Patient 1 was scheduled for surgery but died due to an apneic episode. Patient 2 refused surgery and has been followed for 3 years while his neurologic condition remains unchanged. Patient 3 underwent occipitocervical decompression and fusion, recovered neurologically, and resumed his previous functional skills. Patients demonstrating considerable functional deterioration or insidious change in their established neurologic status should undergo detailed screening to rule out developing upper cervical instability. Early surgical intervention consisting of spinal decompression and fusion may prevent the development of myelopathy.

Should children with Down syndrome be screened for atlantoaxial instability?

In 1995, the Committee on Sports Medicine and Fitness of the American Academy of Pediatrics (AAP) published a position paper on atlantoaxial instability in children with Down syndrome in which a previous statement on the same subject published in 1984 (Table) was retired. The 1995 statement includes several arguments that disfavor screening of children with Down syndrome for atlantoaxial instability. Whereas some of these arguments are well founded, other lack substantive evidence that would support the statement. In the following discussion, I attempt to analyze some of these arguments made in the 1995 statement and provide a viewpoint that favors radiologic examinations of the cervical spine of children with Down syndrome.

Atlanto-Occipital and Atlanto-Axial Instability in Children with Down Syndrome

Thirty-six children with Down syndrome, between two-and-ne-half and 13 years of age, were evaluated for instability of the cervical spine, in order to determine the prevalence of upper cervical spine instability in Saudi children with this condition. Nine patients exhibited abnormal cervical spine movement. Eight patients had atlanto-occipital instability and three had atlanto-axial instability. None of the nine patients with abnormal cervical spine movements developed any neurological deficit. Our survey confirms the data from the literature that there is a high incidence of cervical spine instability in children with Down syndrome.

No relation between general laxity and atlantoaxial instability in children with Down syndrome.

Atlantoaxial instability in children with Down syndrome (DS) may be caused by laxity of the transverse ligament. We tested the hypothesis that general laxity might predict atlantoaxial instability. General laxity and the atlantoaxial distance were assessed in 172 children with DS (aged 6-17 years; 45% girls, 55% boys). No significant correlation was noted between these two measures with either univariate or multivariate methods of statistical analysis.

Symptomatic Atlantoaxial Instability Associated With Medical and Rehabilitative Procedures in Children With Down Syndrome

The Canadian College of Medical Genetics recently questioned the rationale for radiographic screening for atlantoaxial instability in Down syndrome. We report a case series of four children with Down syndrome with symptomatic atlantoaxial instability and followed for more than 5 years. In all cases a medical or rehabilitational procedure was associated with significant apnea, cardiopulmonary compromise, or severe neurological impairments. None of these patients were screened radiographically. The need for protocols to detect atlantoaxial instability in children with Down syndrome undergoing medical and rehabilitational procedures is highlighted by these cases.

The odontoid process in children — is it hypoplastic?

An analysis of the cervical spine of 508 normal children aged between 3 and 18.9 years provided data for the normal development of the odontoid process and its relationship to the anterior arch of the atlas. In normal children under the age of 9 years, the tip of the odontoid may fall well short of the upper margin of the anterior arch of the atlas. This has important implications for the assessment of atlanto-axial instability in children with Down's syndrome.

Atlanto-axial instability in children with Down syndrome.

One hundred fifty-eight patients with Down syndrome underwent roentgenologic examinations of the cervical spine in neutral position, in hyperflexion, and in hyperextension. Fifteen children with Down syndrome were found to have a distance between the joint surfaces of 5 mm and more. The majority of these children were asymptomatic, one child displayed hyperactive deep tendon reflexes and two children were symptomatic and underwent surgery.