Atlanto-occipital subluxation in Down syndrome

Atlanto-occipital subluxation (AOS) in individuals with Down syndrome is discussed using five new cases and nine patients previously presented in the literature. Although AOS is likely due to ligamentous laxity, it was associated with atlantoaxial instability in only two youngsters. Reducible C1–C2 rotary subluxation was present in a third. Posterior movement of the occiput with respect to C1 occurred on extension and reduced on flexion in all but one individual who demonstrated anterior subluxation. Neurological problems are described in only two individuals: one with severe atlantoaxial subluxation (AAS) and the other with multiple cervical spine anomalies. Since AOS is usually detected on films obtained to screen children with Down syndrome for AAS, the atlanto-occipital joint should be carefully studied on these radiographs. The clinical significance of AOS needs to be determined.     

Atlantoaxial instability in individuals with Down syndrome: epidemiologic, radiographic, and clinical studies

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.     

Down syndrome and craniovertebral instability. Topic review and treatment recommendations

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. Copyright Copyright 1999 S. Karger AG, Basel     

Down syndrome. Cervical spine abnormalities and problems

A review of the radiographs of 34 individuals with Down syndrome (DS), between 5 and 21 years of age, demonstrated subluxation of atlantoaxial instability (C1-C2) greater than 5 mm in three of the 34 individuals (9 percent). This is in general agreement with previously reported ranges of 10 to 20 percent. A review of the cervical spine radiographs of adults with DS, between 26 and 42 years of age, showed no subluxation but significant degenerative changes of the cervical spine with spur formation, narrowing of foramina, narrowing of the disc inner space, and osteophyte formation. In both the DS child and the DS adult, the cervical spine may be an area of significant potential problems. In all cases any complaints of cervical pain or historical/clinical findings suggestive of neurologic involvement should initiate evaluation of the cervical spine. Baseline radiographic studies of the cervical spine are indicated in all DS children older than 5 years of age and should be considered in all DS adults, particularly those 30 years of age and older.     

The Special Olympics athlete: evaluation and clearance for participation

Evaluating and clearing the Special Olympics athlete for participation in sports and recreational activities can be a challenging task for a primary care physician. Radiographic clearance of the cervical spine is mandatory for all athletes with Down syndrome. Regular physical activity for this special population has measurable physiologic and psychosocial benefits.     

Atlantoaxial instability in Down syndrome: roentgenographic, neurologic, and somatosensory evoked potential studies

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.     

Craniovertebral abnormalities in Down's syndrome.

The ligamentous laxity associated with atlantoaxial subluxation has been assumed as a normal occurrence in 15-20% of Down's syndrome patients. The occipitoatlantoaxial instability that accompanies this entity has been poorly recognized. The medical records and radiographic findings of 18 symptomatic patients with Down's syndrome and cervicomedullary compromise were reviewed (1979-1991). All patients were evaluated prospectively under protocol for abnormalities of the cranial vertebral junction. There were 11 males and 7 females (age 3-42). 'Fixed' atlantoaxial luxation was seen in 8 (5 developed precipitous onset of cervical medullary compression). Occipitoatlantoaxial instability was present in 9 and associated rotary luxation in 9. The average predental space was 8 mm in the neutral position in 18 individuals. Two adolescents had previously undergone atlantoaxial dorsal fusion with subsequent progressive basilar invagination due to unrecognized occipitoatlantal instability. An os odontoideum was seen in 3 patients. Irreducible invagination in 2 was treated with anterior decompression followed by dorsal occipital cervical fixation. The occipital cervical fixation was utilized in 10 individuals. Atlantoaxial dorsal fusion was made in 7 and 2 patients with acute rotary luxation of C1 and C2 were treated with immobilization. Halo immobilization in two individuals following a dorsal occipital cervical fixation produced an anterior fusion at the cranial vertebral complex indicating active vertebral ligamentous pathology. The review focuses on increased incidence of occiput cervical instability in the spectrum of craniovertebral junction abnormalities associated with Down's syndrome. A large percentage has an odontoid ossicle probably as a result of repeated minor trauma. The results of surgical stabilization have been shown to be excellent.     

小儿严重寰枢椎不稳的手术治疗

目的 探索小儿严重寰枢椎不稳的手术治疗方式。方法 回顾总结22例小儿严重寰枢椎不稳的临床资料。男16例,女6例,年龄3-14岁,平均11.4岁,病因有齿突骨折、横韧带断裂、枕颈畸形、类风湿关节炎等,所有患儿均行后路融合术,其中寰枢椎融合14例,枕颈融合术8例。结果 20例患儿经平均20个月（3个月-11年）随访,均获骨性融合,取得满意效果。结论 上颈椎后路融合术是治疗小儿严重寰枢椎不稳的有效方法,对寰枢椎能复位者选择寰枢椎融合,脱位不能复位者应行枕颈融合术。     

Radiological assessment of the atlantoaxial distance in Down's syndrome.

People with Down's syndrome are pre-disposed to atlantoaxial instability. As part of a study to determine whether those with Down's syndrome should be screened for atlantoaxial instability before they participate in sport, a series of 279 children, aged 6 to 17 years was investigated radiologically. Lateral radiographs of the cervical spine were taken in neutral position and in flexion. The magnification factor was assessed by means of a marker attached to the nape of the neck. After correction for magnification 15% of the patients were found to have an atlantoaxial distance greater than 4 mm on the flexion film, especially boys under 11 years of age. However, sex and age together explained at most 9% of the variation in atlantoaxial distance. The maximum distance found was 6.5 mm. The disagreement between the means of first and second measurements by the same (test-retest) and by another (inter-) observer was more for those taken in the neutral position than in flexion. On a group level the results for reliability were satisfactory.     

Radiological assessment of the atlantoaxial distance in Down's syndrome

People with Down's syndrome are pre-disposed to atlantoaxial instability. As part of a study to determine whether those with Down's syndrome should be screened for atlantoaxial instability before they participate in sport, a series of 279 children, aged 6 to 17 years was investigated radiologically. Lateral radiographs of the cervical spine were taken in neutral position and in flexion. The magnification factor was assessed by means of a marker attached to the nape of the neck. After correction for magnification 15% of the patients were found to have an atlantoaxial distance greater than 4 mm on the flexion film, especially boys under 11 years of age. However, sex and age together explained at most 9% of the variation in atlantoaxial distance. The maximum distance found was 6.5 mm. The disagreement between the means of first and second measurements by the same (test-retest) and by another (inter-) observer was more for those taken in the neutral position than in flexion. On a group level the results for reliability were satisfactory.     

Down syndrome: orthopedic issues

PURPOSE OF REVIEW: The purpose of this review is to update the role of the orthopedic surgeon in the management of Down syndrome as these patients are living longer and participating in sporting activities. RECENT FINDINGS: Approximately 20% of all patients with Down syndrome experience orthopedic problems. Upper cervical spine instability has the most potential for morbidity and, consequently, requires close monitoring. Other conditions such as scoliosis, hip instability, patellar instability and foot problems can cause disability if left untreated. In some of these conditions, early diagnosis can prevent severe disability. SUMMARY: Surgical intervention in children with Down syndrome has a high risk of complications, particularly infection and wound healing problems. Careful anesthetic airway management is needed because of the associated risk of cervical spine instability.     

Down syndrome: imaging of multiorgan involvement.

Down syndrome (trisomy 21) has many manifestations that affect multiple organ systems, and we describe the wide array of imaging findings. Common cardiovascular and gastrointestinal entities are congenital heart disease (atrioventricular canal), bowel atresias (duodenal and anal), and Hirschsprungs disease. Children with Down syndrome have an 18-20 fold increased incidence of leukemia. Pulmonary hypoplasia, lung cysts, and pig bronchus (origin of the right upper lobe bronchus from the trachea) have been described. Neurologic findings include mineralizing vasculopathy of the basal ganglia, Moyamoya disease, and cerebellar/vermian hypoplasia. Musculoskeletal manifestations are numerous and include eleven ribs, hypersegmented sternum, abnormal pelvis, joint laxity/dislocations, and DDH (developmental dysplasia of the hip). Of special importance is the "triple jeopardy" of the upper cervical spine (atlanoaxial subluxation, hypoplastic posterior arch of C1, and atlantooccipital instability) and the resulting controversial cervical spine radiographic screening of children with Down syndrome. Knowledge of the many anomalies associated with Down syndrome can aid the clinician, not only in diagnosing abnormalities in these patients, but also in counseling families for potential problems that can occur in these children.     

Instability and dislocation of the hip in Down syndrome: report of two cases and proposition of a diagnostic protocol

The authors report two cases of children with Down syndrome presenting with different patterns of instability of the hip. A 4-year-old girl with delay in the acquisition of walking presented with a painless 'habitual dislocation'. An 11-year-old girl presented with 'subluxation' of the hip, painful after long walks. Surgical treatment combining soft tissues and bone procedures (including reduction and plastic of the redundant capsule in both cases, differently associated with femoral varus and derotational osteotomy using Scaglietti screws and pelvic osteotomy according to Zanoli-Pemberton) provided excellent radiographic (improvement in radiographic indices) and functional (the first patient began walking without falls; pain disappeared in the second patient) result. With increasing life expectancy of patients with trisomy 21, the incidence of painful arthritis of the hip in adulthood is also rising, contributing to progressive loss of walking ability. Early diagnosis and correct treatment of young patients presenting with hip instability are mandatory to reduce this disabling pathologic condition. The authors review the literature about natural history and possible treatments of hip instability and dislocation, and propose a diagnostic protocol to use in the case of children with Down syndrome.     

Odontoid hypoplasia with vertebral cervical subluxation and ventriculomegaly in metatropic dysplasia

Our experience with 12 patients with metatropic dysplasia has demonstrated two important and treatable complications: odontoid hypoplasia with subluxation of the first and second cervical vertebrae, and ventriculomegaly. Hypoplasia and lack of ossification of the odontoid process were noted in all cases. Subluxation of these two vertebrae was demonstrated in all six patients who had lateral flexion-extension radiographs; three had subluxation even in a neutral position, and sudden odontoid dislocation developed in another after a simple fall. Four individuals have had surgical fusion of the cervical vertebrae; one child died suddenly, 1 week before scheduled surgery. In the three patients in whom computed tomography scans of the head were obtained, enlarged ventricles were found; one had symptomatic increased intracranial pressure and required a shunt. We recommend that odontoid hypoplasia be evaluated in all patients with metatropic dysplasia. If subluxation is proved, atlantoaxial fusion should be performed before damage to the cervical part of the spinal cord results. Serial head circumference measurements and evaluation for hydrocephalus are also recommended.     

Atlanto-axial dislocation with spinal cord compression in Down syndrome

ABSTRACT. An 8-year-old female with Down syndrome presented with progressive spastic quadriparesis. Compression of the upper cervical spinal cord was due to atlanto-axial dislocation and she died despite operative intervention. Details of clinical, radiological and pathological features are presented.     

C1-2 instability from os odontoideum mimicking intramedullary spinal cord tumor

Os odontoideum is a common cause of atlantoaxial instability in the pediatric population. The authors present the cases of 2 patients whose initial clinical presentation and MR imaging findings were suggestive of an intramedullary neoplasm, but whose ultimate diagnosis was determined to be cervical spine instability and cord injury due to os odontoideum.     

Human immunodeficiency virus and other blood-borne viral pathogens in the athletic setting. Committee on Sports Medicine and Fitness. American Academy of Pediatrics

Because athletes and the staff of athletic programs can be exposed to blood during athletic activity, they have a very small risk of becoming infected with human immunodeficiency virus, hepatitis B virus, or hepatitis C virus. This statement, which updates a previous position statement of the American Academy of Pediatrics, (1) discusses sports participation for athletes infected with these pathogens and the precautions needed to reduce the risk of infection to others in the athletic setting. Each of the recommendations in this statement is dependent upon and intended to be considered with reference to the other recommendations in this statement and not in isolation.     

Atlantoaxial instability and abnormalities of the odontoid in Down's syndrome.

Radiography of the lateral neck was performed on all children with Down''s syndrome aged 4-15 in the Southern Derbyshire health district (n = 67) and a random selection of adults (n = 94). Atlantoaxial instability, defined as a gap of over 4 mm, was present in seven (10%) children and two (2%) adults. Odontoid hypoplasia, defined as an odontoid peg two standard deviations below the mean in an age matched population, was present in 15 (22%) children and 14 (15%) adults, with accessory odontoid ossicles present in two (2%) and two (3%) respectively. No one was found to have symptoms or clinical signs of spinal cord compression. Atlantoaxial instability was therefore found to be commoner in children than adults. Different programmes of management are suggested, in terms of regular clinical examination for signs and symptoms and by radiographic screening. Particular care should be taken with those who have both atlantoaxial instability and odontoid hypoplasia or accessory ossicles as they are at particular risk of spinal cord damage.     

Cholelithiasis in infants with Down syndrome. Three cases and literature review.

Only four cases of cholelithiasis have been reported in patients with Down syndrome and none in Down syndrome infants. The cases of three Down syndrome infants (all males) with cholelithiasis are reported. Each exhibited different fetal complications, and in each, Down syndrome was diagnosed at birth. Gallstones apparently were congenital (a rarity) in one infant, since they were detected on the first day of life. Cholelithiasis was an incidental finding in another of the infants when, at 12 weeks old, he had renal ultrasonography because of a urinary tract infection. The third infant was 4 months old when sonographic studies revealed a gallstone. Despite the confirmation of cholelithiasis in all three infants, none has since had any signs or symptoms that suggest the need for intervention. Cholelithiasis is probably more common in Down syndrome infants than has been supposed, but whether Down syndrome infants with gastrointestinal (GI) malformations are more likely to have gallstones than are children with similar GI malformations but with normal karyotypes is unknown.     

Trisomie 21 et autisme : double diagnostic, évaluation et intervention

Autism is recognized as an additional diagnosis possible in people with Down syndrome. This pathology is still rarely detected and treated in this population in France. This article is a review of the English literature and of studies led during the last fifteen years. Studies have identified the expression of autism clinical signs in children with Down syndrome and the sensitivity and specificity of diagnostic instruments for autism in this population despite their cognitive impairments. This paper emphasizes authors’ recommendations about intervention taking into account the dual diagnosis: they encourage the identification of autism as well as early and appropriate intervention for those children whose needs differ from their peers without comorbid disorder. These results show the need to educate professionals about the importance of the detection of autism in children with Down syndrome, and the prevention that could follow.