Reproducibility in the Measurement of Atlanto-occipital Instability in Children With Down Syndrome

Karol, Lori A.; Sheffield, Eugene G.; Crawford, Kevin; Moody, Marilyn K.; Browne, Richard

doi:10.1097/00007632-199611010-00010

Cited by 32 publications

(6 citation statements)

References 15 publications

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“…This is particularly useful for the diagnosis of atlanto-occipital dislocation (AOD) [2,[5][6][7][8]11]. A strong correlation between the AOD and Powers ratio has been supported by both experimental and clinical studies using various methods including X-ray, CT and threedimensional CT [2,7,11].…”

Section: Introductionmentioning

confidence: 99%

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Interobserver reliability and intraobserver reproducibility of powers ratio for assessment of atlanto-occipital junction: comparison of plain radiography and computed tomography

Passias

Kozánek

et al. 2009

Eur Spine J

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Powers ratio, as assessed on plain radiographs or computed tomography (CT) images, appears to have clinical and prognostic value. To date, the validation of this assessment tool has been limited to a small number of observers at a single site. No study has examined the intraobserver reproducibility and interobserver reliability of the Powers ratio measurement on plain radiographs or CT images among a large cohort of spine surgeons. This type of validation is critical to allow for the broader use of the Powers ratio methodology in research studies and clinical applications. Plain radiographs and spiral CT images of the cervical spine of 32 patients were assessed, and the Powers ratio was determined by five spine surgeons. Each surgeon performed three readings, 7 months apart. In the first round of measurements, the observers used only the Powers' method of instruction. The second and third measurement sets were obtained after an interactive teaching session on the methodology. The order of the images was altered for the second and third set of measurements. The coefficient of variation (Cv) was calculated to determine the intraobserver repeatability and interobserver reliability for each imaging technique. A Bland-Altman plot was then used to assess the agreement between the two imaging techniques. For interobserver reliability, the mean Cv of the Powers ratio was 9.09 and 4.31% for plain radiographs and CT, respectively. The Cv mean value for intraobserver reproducibility averaged 4.95% (range 1.39-9.08) when CT scans were used and 14.17% (range 7.54-34.30) when plain radiographs were used. For intraobserver reproducibility, the lowest and highest Cv mean value of five raters was 1.39 and 9.08% using CT scans and 7.54 and 34.3% using plain radiographs. The Bland-Altman plot, demonstrated that the two methods were in close agreement on the -0.8 and 0.89% interval for limits of agreement (bias ± 1.96r). The intraobserver reproducibility and interobserver reliability of Powers ratio measurement was acceptable (\5%) with CT scans but not with plain radiographs. However, despite the statistically inferior reliability and repeatability, the Bland-Altman plot analysis showed that given the -0.8 and 0.89% limits of agreement, the two methods may be used interchangeably in clinical practice.

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Section: Introductionmentioning

confidence: 99%

“…X-line method, condylar gap and Harris method [2,6,7]. However, very few of them have focused on intraobserver reproducibility and interobserver reliability.…”

Section: Introductionmentioning

confidence: 99%

Interobserver reliability and intraobserver reproducibility of powers ratio for assessment of atlanto-occipital junction: comparison of plain radiography and computed tomography

Passias

Kozánek

et al. 2009

Eur Spine J

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“…The systematic radiographic screening for instability is of unproven value [79,86]. A regular clinical assessment is much more helpful.…”

Section: Down Syndromementioning

confidence: 99%

Pediatric cervical spine instability

Ghanem

Hage

Rachkidi

et al. 2008

Journal of Children's Orthopaedics

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Cervical spine instability in children is rare but not exceptional and may be due to many factors. Although it mostly occurs at the upper cervical spine, all vertebrae from the occiput to T1 may be involved. It may be acute or chronic, occurring secondary to trauma or due to congenital anomaly, skeletal or metabolic dystrophy or rheumatoid arthritis. It can be isolated or associated with other musculoskeletal or visceral anomalies. A thorough knowledge of embryology, anatomy, physiology and physiopathology of the cervical spine in children is essential to avoid pitfalls, recognize normal variants and identify children at risk of developing cervical spine instability and undertake the appropriate treatment.

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“…Axial separation is prevented between C1 and C2, because of the strong constraint by the transverse ligament positioned behind a normally configured dens. Any deformity to the dens (such as that found in Downs syndrome) 24 could potentially reduce upper cervical stability, produce excessive separation, and merit avoiding any therapeutic cervical traction maneuvers. In addition, a gap, which can be appreciated on sagittal view X‐ray between the dens and the anterior arch of C1, is full of cartilage and should not exceed 3 mm, even during cervical flexion or extension.…”

Section: Pathoanatomymentioning

confidence: 99%

Diagnosis and Management of Cervicogenic Headache

Sizer

Phelps²,

Azevedo

et al. 2005

Pain Practice

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Upper cervical pain and/or headaches originating from the C0 to C3 segments are pain-states that are commonly encountered in the clinic. The upper cervical spine anatomically and biomechanically differs from the lower cervical spine. Patients with upper cervical disorders fall into two clinical groups: (1) local cervical syndrome; and (2) cervicocephalic syndrome. Symptoms associated with various forms of both disorders often overlap, making diagnosis a great challenge. The recognition and categorization of specific provocation and limitation patterns lend to effective and accurate diagnosis of local cervical and cervicocephalic conditions.

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Reproducibility in the Measurement of Atlanto-occipital Instability in Children With Down Syndrome

Abstract: Measurement of atlanto-occipital translation by any of these methods is not reproducible. Although the technique by Wiesel and Rothman is the easiest to apply, confirmation of instability with magnetic resonance imaging should guide management.

Cited by 32 publications

References 15 publications

Interobserver reliability and intraobserver reproducibility of powers ratio for assessment of atlanto-occipital junction: comparison of plain radiography and computed tomography

Interobserver reliability and intraobserver reproducibility of powers ratio for assessment of atlanto-occipital junction: comparison of plain radiography and computed tomography

Pediatric cervical spine instability

Diagnosis and Management of Cervicogenic Headache

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