Atlantoaxial Instability & Down Syndrome Abstracts

Nepal Journal of Neuroscience 2(1): 52-58 (2005 Jan)

Down's Syndrome and Craniovertebral Instability: Topic Review and Treatment Recommendations

Douglas Brockmeyer
Division of Pediatric Neurosurgery, Primary Children's Medical Center, Salt Lake City, UT 84113

Down's syndrome, is the most common inherited chromosomal disorder in humans occurring in 1.5 in every 1,000 live births and is characterized by multiple neurological as well as nonneurological abnormalities. The issue of craniovertebral instability in Down's syndrome patients is a very controversial topic. Multiple studies and editorials have been written over the last two decades and much of the information is conflicting and confusing. The goal of this review is to provide a rational synthesis of this previous work and provide recommendations by which parents of Down's syndrome patients, pediatricians, family practitioners and other health professionals may make intelligent choices regarding screening of Down's syndrome patients. It is a second goal of this review to synthesize the surgical data on this topic and provide recommendations for anesthesiologists, otolaryngologists, orthopedic surgeons and neurosurgeons.
Rev Neurol 30 (12): 1101-7 (2000 Jan 16-30)

A radiological study of the cervical alterations in Down syndrome. New findings on computerized tomography and three dimensional reconstructions

Cros T, Linares R, Castro A, Mansilla F
Servicio de Radiologia, Hospital General de Albacete, España

OBJECTIVE: We studied a large proportion of the population in our health district who have Down's syndrome to determine the incidence and variety of changes in the spine and to define the guidelines for preventive diagnosis advisable in relation to atlanto-axial instability, a common disorder in these patients. PATIENTS AND METHODS: First phase: a plain X-ray of the cervical spine in a neutral lateral projection and in flexion in 188 patients, measuring the atlanto-odontoid distance. Second phase: computerized tomography (CT) studies and three dimensional reconstructions in 25 patients (13.3%) chosen at random. The axial cuts from the upper portion of C3 to the occiput were 3 mm in thickness with 3 mm intervals and a standard reconstruction algorithm. RESULTS: The incidences of atlanto-axial instability with an atlodontoid distance (3)5 mm were not comparable with the published series. There was a lower incidence (4.2%), with no difference between measurements in flexion and in the neutral lateral views. There was a greater incidence of malformations than in other reports, including a rare case of os odontoideum and also constant asymmetry of the occipital condyles (100%) in the patients of the CT series and consequently instability of the atlas (96%) and off-centered odontoides (84%). CONCLUSIONS: The study showed that there was deficient asymmetrical development of the occipital bone, which caused different heights of the occipital condyles and led to cervico-cranial mal-position. For study of the degree of error of position and congenital anomalies. We recommend replacing plain X-ray studies by CT with three dimensional reconstructions.
Pediatr Neurosurg 31 (2): 71-7 (1999 Aug)

Down syndrome and craniovertebral instability: Topic review and treatment recommendations

Brockmeyer D
Division of Pediatric Neurosurgery, Primary Children's Medical Center, Salt Lake City, Utah, USA

The diagnosis and management of occipital-atlantal and atlantoaxial instability in Down syndrome patients is a challenging problem in pediatric spine surgery. To date, no systematic review of this topic has been presented on this confusing and sometimes contentious issue. This topic review will focus on the biomechanical and radiographic foundations for which treatment recommendations in Down syndrome patients are made. In addition, otolaryngologic and anesthetic considerations in Down syndrome are also discussed, as well as advances in surgery that have made the operative fusion of these patients easier and safer.
Med J Aust 165 (8): 448-450 (1996 Oct 21)

Screening of Children with Down Syndrome for Atlantoaxial (C1-2) Instability: Another Contentious Health Question

Taylor TK, Walter WL
SpineCare Foundation, Sydney, NSW

Screening for atlantoaxial (C1-2) instability in children with Down syndrome before their participation in sport is called into serious question. Despite the lack of clear supporting data to justify screening, it has been widely recommended and enforced by some sporting organisations for several decades. Experience in New South Wales during the past 25 years strongly suggests that routine screening should be discontinued, and the existing literature supports this move.
J Pediatr Orthop 15 (4): 543-8 (1995 Jul-Aug)

Posterior Spinal Arthrodesis for Atlantoaxial Instability in Down Syndrome

Rizzolo S; Lemos MJ; Mason DE
Alfred I. duPont Institute, Wilmington, Delaware 19899, USA

Nine children with Down syndrome who had atlantoaxial instability underwent posterior spinal fusion. At follow-up, all patients had stabilization or improvement of their neurologic symptoms. Evaluation of the spine using flexion and lateral radiographs, as well as selective cineradiography, showed no instability over the fused area or adjacent motion segments. Stable fibrous union with no clinical significance was noted in three of the nine patients. We recommend posterior spinal fusion in situ with external immobilization as the safest and most effective means of surgical stabilization in the patient with Down syndrome who has symptomatic atlantoaxial instability.
Arch Dis Child 72(2): 115-8 (1995 Feb)

Atlantoaxial instability in Down's syndrome: a five year follow up study

Morton RE, Khan MA, Murray-Leslie C, Elliott S.
Ronnie MacKeith Child Development Centre, Derbyshire Royal Infirmary.

In 1986 all 90 children aged 4-19 years with Down's syndrome attending school in the area served by the Southern Derbyshire Health Authority underwent radiography to identify atlantoaxial instability (AAI). This study details repeat observations five years later. Full results were available on 67 (74%), information on health status was available on the remaining 19 (21%); four (4%) were untraced. There was an overall significant reduction in the atlanto-axial gap over five years. No one developed AAI on repeat testing who had not had it earlier. One child who had previously had normal neck radiography developed acute symptomatic AAI after ear, nose, and throat surgery. Radiographs were done on three occasions on the same day in 49 individuals, ensuring full flexion of the upper neck. There were no significant differences between the radiographs, even in five subjects with AAI. Management of AAI in Down's syndrome is discussed in the light of these findings. Radiography can reliably detect children with chronic AAI who may be at risk of gradually developing symptoms; this may justify a screening programme. This must be distinguished from those who develop symptoms after acute trauma or anaesthesia, for which specific precautions are needed, and previous screening radiographs are unhelpful.
Paediatr Anaesth 5 (6): 355-61 (1995)

Preoperative Evaluation of the Cervical Spine in Children with Trisomy-21: Results of a Questionnaire Study

Litman RS; Zerngast BA; Perkins FM
Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, New York 14642, USA

Atlantoaxial subluxation (AAS) is a form of cervical spine instability predominantly found in persons with Trisomy-21. Several case reports describe the occurrence of acute AAS in the perioperative period. Some authors have recommended cervical spine radiographs prior to elective surgery in all children with Trisomy-21. The objective of this study was to determine practice patterns of North American members of the Society of Pediatric Anesthesia with regard to the perioperative evaluation and management of potential cervical spine instability in patients with Trisomy-21. Of 171 respondents, a minority of respondents (18%) obtain preoperative radiographs and/or subspecialty consultation (9%) in asymptomatic children with Trisomy-21. For symptomatic children the majority of respondents would obtain radiographs (64%) and/or preoperative consultation (74%). Approximately half of the respondents would attempt to maintain the head and neck in a neutral position for either asymptomatic (42%) or symptomatic (55%) patients. We conclude that the majority of respondents base their preoperative evaluation of the cervical spine on the signs and symptoms of the patient. This is supported by the literature reviewed, but is contrary to the recommendations made in some case reports.
Arch Otolaryngol Head Neck Surg 120 (2): 159-65 (1994 Feb)

Neurologic Sequelae Secondary to Atlantoaxial Instability in Down Syndrome. Implications in Otolaryngologic Surgery

Harley EH; Collins MD
Department of Otolaryngology, Naval Hospital, San Diego, CA

OBJECTIVE: A comprehensive overview of atlantoaxial instability in Down syndrome as it relates to head and neck surgery and recommendations as derived from a review of the literature. DATA SOURCES: English-language literature: otolaryngologic problems in Down syndrome and atlantoaxial biomechanics. DATA SYNTHESIS: Children affected with Down syndrome frequently require otolaryngologic procedures such as myringotomy with ventilation tubes or adenotonsillar surgery. Atlantoaxial instability occurs in 10% to 20% of patients with Down syndrome who are at risk for atlantoaxial subluxation and subsequent complications during anesthetic induction and during positioning and manipulation associated with surgery. To identify patients who are at risk for atlantoaxial subluxation, guidelines have been adapted from the recommendations of the American Academy of Pediatrics and the Special Olympics Inc, which include preoperative neurologic assessments and cervical roentgenograms in the neutral, flexion, and extension positions. Children with an atlantodental interval of greater than 4.5 mm or with peripheral neurologic findings should have further evaluation. CONCLUSIONS: A small percentage of patients with Down syndrome are at risk for atlantoaxial instability and subluxation. All patients with Down syndrome should have a preoperative neurologic assessment screening by the operating surgeon and/or a cervical roentgenogram in the lateral, extension, and flexion positions. Any abnormality should be investigated before surgery.
Lancet 243 (8870): 511-4 (1993 Aug)

Risk of Sports Activities in Children with Down's Syndrome and Atlantoaxial Instability

Cremers MJ; Bol E; de Roos F; van Gijn J
Janus Jongbloed Research Center, University Department of Physiology and Sports, Utrecht, Netherlands

10-40% of children with Down's syndrome have atlantoaxial instability. These children might run the risk of spinal cord compression if they play sport. The aim of our study was to assess this presumed risk. We obtained 282 radiographs of the cervical spine from a cohort of 400 children and young adults with Down's syndrome who attended special schools and who were between 4 and 20 years old (about 25% of all such children in the Netherlands). The atlantoaxial distance was more than 4 mm in 91 children. These children were randomly assigned to two groups, with the provision that all children at any particular school were assigned to the same group. Children of one group were allowed to continue their habitual sports and exercise activities, whereas those in the other group were advised not to play "risky" sports (as defined by a panel of four experts) and not to make "risky" movements during physical education lessons. The compliance of the experimental group was good. After a year, there were no differences between the groups in scores on a functional motor scale, the frequency of neurological signs, or changes in the atlantoaxial distance. The motor function of a third group of 44 children with Down's syndrome but normal atlantoaxial distances was similar to that of children in the other two groups, as was the frequency of neurological signs. These findings suggest there is no reason to stop children with Down's syndrome from playing certain sports and no need to screen them by radiography before they take up such sports activities.
Spine 17 (7): 735-737 (1992 Jul)

Computerized Tomography in Persons with Down Syndrome and Atlantoaxial Instability

Pueschel SM, Moon AC, Scola FH
Department of Pediatrics, Rhode Island Hospital, Brown University Program in Medicine, Providence

Atlantoaxial instability has been reported to occur in 9-31% of persons with Down syndrome. The authors studied a subsample of patients with this chromosomal disorder who had both routine roentgenograms and computerized tomographic examinations. Computerized tomography revealed numerous skeletal anomalies of the C1-C2 region as well as spinal cord compression that were not visualized on plain roentgenograms. In addition, an apparent discrepancy of the atlanto-dens interval measurements between the two procedures was noted. The measurements of the plain roentgenograms were significantly greater than those obtained by computerized tomography, which is due to the magnification factor in plain roentgenograms.
Arch Dis Child 66(7): 876-8 (1991 Jul)

Clinical predictors and radiological reliability in atlantoaxial subluxation in Down's syndrome

Selby KA, Newton RW, Gupta S, Hunt L.
Royal Manchester Children's Hospital.

Clinical signs and symptoms that might predict atlantoaxial subluxation were studied prospectively in 135 of 180 children with Down's syndrome aged 6-14 years who form the Hester Adrian Research Centre cohort. Lateral radiographs of the cervical spine were taken in flexed, extended, and neutral positions, and the percentage of abnormalities in each view was 14, 10, and 10%, respectively. Gait was the only significant clinical predictor. The relative risk of having an abnormal neck radiograph with an abnormal gait was 2.91 (95% confidence interval (CI) 1 to 8). The sensitivity was 50% and the specificity 81%. Nineteen children had repeat radiographs to assess the reliability of radiological diagnosis. Six had abnormalities; five of 19 (26%) had an abnormality on the first radiograph, and four of 19 (21%) had an abnormality on a second radiograph, but only three (15%) had an abnormality on both occasions in any view (95% CI 0 to 25). We conclude that radiographs of the cervical spine are unreliable at identifying atlantoaxial subluxation in children with Down's syndrome, and we failed to identify any reliable clinical predictor.
J R Soc Med 83 (7): 433-435 (1990 Jul)

Atlantoaxial Instability in Down Syndrome—Guidelines for Screening and Detection

Roy M, Baxter M, Roy A
Monyhull Hospital, Kings Norton, Birmingham

A community survey was conducted in all adults with Down syndrome living in three health districts to see if there was any correlation between radiological and neurological abnormalities which could indicate the presence of atlantoaxial instability. There was no difference in the proportion of individuals with neurological abnormalities in the group with radiological abnormalities suggestive of atlantoaxial instability (6/14) compared with individuals with normal X-rays (50/123) as determined by the chi square test (0.01463: not significant). The clinical and ethical implications for screening of people with Down syndrome living in the community are discussed in view of these findings.
Pediatrics 85 (3 Pt 2): 447-449 (1990 Mar)

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

Msall ME, Reese ME, DiGaudio K, Griswold K, Granger CV, Cooke RE
Division of Developmental Pediatrics, Rehabilitation and Developmental Disabilities, Robert Warner Rehabilitation Center, Children's Hospital of Buffalo, NY

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.
Pediatrics 81 (6): 857-865 (1988 Jun)

Atlantoaxial Instability in Individuals with Down Syndrome: A Fresh Look at the Evidence

Davidson RG
Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada

In 1984, the Committee on Sports Medicine of the American Academy of Pediatrics published in this journal a statement on the remarkably high incidence of atlantoaxial instability among individuals with Down syndrome. On the assumption that this instability, demonstrable through a specified series of lateral x-ray films of the neck, constituted a predisposition to cervical spine dislocation with subsequent spinal cord compression, the Academy supported and made more specific a series of recommendations that had originated from the Kennedy Foundation a year previously. In essence, for those persons who are found to have the radiographic sign of instability, participation in sports should be restricted. Because the implementation of these recommendations could deprive tens of thousands of individuals with Down syndrome of activities that are emotionally and physically beneficial and because of the rarity of reported cervical dislocations associated with injury, a case review was done. Included were those cases cited as support for the recommendations along with additional reports that had been omitted and a few cases reported subsequently. Little support for the hypothesis that atlantoaxial "instability" is a predisposing factor to "dislocation" was found, although much was found to indicate an urgent need for carefully designed longitudinal studies. Because nearly all of the cases of actual dislocation were preceded by at least several weeks of readily detectable physical signs, a physical examination with careful attention to neurologic signs prior to participation in sports is more predictive of potential or impending dislocation than the radiologic criteria currently recommended.
Pediatrics 80 (4): 555-560 (1987 Oct)

Atlantoaxial Instability in Individuals with Down Syndrome: Epidemiologic, Radiographic, and Clinical Studies

Pueschel SM, Scola FH
Child Development Center, Department of Pediatrics, Providence, RI 02902

Atlantoaxial instability is a relatively frequent finding in individuals with Down syndrome. We examined 404 patients with this chromosome disorder and observed their atlanto-dens intervals and spinal canal widths to be significantly different from children without Down syndrome. Significant differences were also noted between boys and girls with Down syndrome in spinal canal widths but not in atlanto-dens interval measurements. When different neck positions were compared, measurements obtained in flexion were significantly greater than in extension or in neutral position. In addition, more patients had greater than or equal to 5 mm atlanto-dens interval measurements in flexion than in extension or neutral. A total of 59 (14.6%) of 404 patients displayed atlantoaxial instability. Fifty-three (13.1%) patients had asymptomatic atlantoaxial instability, and special precautions will have to be taken with this group of children. Six (1.5%) patients had symptomatic atlantoaxial instability who underwent surgery to prevent further injury to the spinal cord. In our follow-up studies of 95 patients with Down syndrome, we did not find any significant changes during either clinical or radiographic reexaminations.
J Pediatr 110 (4): 515-521 (1987 Apr)

Atlantoaxial Instability in Down Syndrome: Roentgenographic, Neurologic, and Somatosensory Evoked Potential Studies

Pueschel SM, Findley TW, Furia J, Gallagher PL, Scola FH, Pezzullo JC

To identify patients with Down syndrome and asymptomatic atlantoaxial instability who are at increased risk for developing neurologic symptoms, we studied 27 patients with this skeletal disorder and compared them with an age- and sex-matched group of 27 patients with Down syndrome without atlantoaxial instability. A third group of six patients had symptomatic atlantoaxial instability. The mean atlanto-dens intervals and the mean spinal canal widths among the three groups were significantly different. There were no significant differences in mean composite neurologic scores and somatosensory evoked responses between patients in the asymptomatic group and those in the control group. However, when a subsample of patients with high and low latencies (greater than 1 SD below and above the mean) was formed and comparisons were made with roentgenographic findings, there was a high correspondence between somatosensory evoked potential latencies and atlanto-dens interval measurements. We conclude that no single assessment technique, but a combined approach using roentgenographic, CT scan, neurologic, and neurophysiologic investigations, will provide information of the risk status of patients with Down syndrome and atlantoaxial instability.