Computed tomography parameters for atlantooccipital dislocation in adult patients: the occipital condyle–C1 interval

Abstract

<jats:sec> <jats:title>OBJECT</jats:title> <jats:p>Atlantooccipital dislocation (AOD) in adults cannot be diagnosed with adequate specificity and sensitivity using only CT or plain radiography, and the spine literature offers no guidelines. In children, the most sensitive and specific radiographic measurement for the diagnosis of AOD is the CT-based occipital condyle–C1 interval (CCI). The goal of the current study was to identify the normal CCI in healthy adults and compare it with the CCI in adults with AOD to establish a highly sensitive and specific cutoff value for the neuroimaging diagnosis of AOD.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>A total of 81 patients, 59 without AOD and 22 with AOD, were included in this study. Measurements obtained from thin-slice CT scans of the craniovertebral joint to assess atlantooccipital dislocation included the CCI, condylar sum, the Wholey and Harris intervals, Powers and Sun ratios, Wackenheim line, and Lee X-lines.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>The group of patients without AOD included 30 men (50.8%) and 29 women (49.2%) with a mean age of 42.4 ± 16 years (range 19–87 years). The group of patients with AOD included 10 men (45.5%) and 12 women (54.5%) with a mean age of 38.2 ± 9.7 years (range 20–56 years). Interrater reliabilities within a 95% CI were all greater than 0.98 for CCI measurements. A total of 1296 measurements of the CCI were made in 81 patients. The mean CCI for non-AOD patients was 0.89 ± 0.12 mm, the single largest CCI measurement was 1.4 mm, and the largest mean for either right or left CCI was 1.2 mm. The mean condylar sum was 1.8 ± 0.2 mm, and the largest condylar sum value was 2.2 mm. Linear regression with age predicted an increase in CCI of 0.001 mm/year (p &lt; 0.05). The mean CCI in AOD patients was 3.35 ± 0.18 mm (range 1.5 mm–6.4 mm). The shortest single CCI measurements in the AOD patients were 1.1 mm and 1.2 mm. The mean condylar sum for all 22 AOD patients was 6.7 ± 2.7 mm and the shortest condylar sums were 3.0 mm. Cutoff values for AOD were set at 1.5 mm for the CCI and 3.0 mm for the condylar sum, both with a sensitivity of 1 and false-negative rate of 0. Sensitivity for the Powers, Wholey, Harris, Sun, Wackenheim, and Lee criteria were determined to be 0.55, 0.46, 0.27, 0.23, 0.41, and 0.41, respectively.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>The CCI is shorter in adult patients as opposed to the pediatric population. The revised CCI (1.5 mm) and condylar sum (3.0 mm) cutoff values have the highest sensitivity and specificity for the diagnosis of AOD in the adult population.</jats:p></jats:sec>

Failure of the Condyle-C1 Interval Method to Diagnose Atlanto-occipital Dislocation in the Presence of an Associated Atlanto-axial Dislocation: A Case Report

“…A revised CCI was done by Gire, Roberto, Bobinski, and Klineberg [ 3 ], and stated that AOD can be accurately diagnosed by a unilateral dislocation or dissociation in the sagittal plane of the C1 joint of 2.5 mm. The revised CCI had a 100% sensitivity, specificity, positive predictive value, and negative predictive value and has been confirmed in other studies [ 2 , 4 ].…”

“…In a study by Campo, Kalb, and Baron [ 4 ], the CCI was proposed to be 1.5 mm as the upper limit of the normal values with a 100% sensitivity and specificity. Other studies report 2.5 mm as the cut off [ 2 - 3 ].…”

“…The current recommendation for diagnosis is to measure the condyle-C1 interval (CCI) using a CT scan in the coronal plane and more recently in the sagittal plane [ 2 - 4 ]. This method has been proven to provide the diagnosis with very high sensitivities and positive predictive values approaching 100%.…”

A 2D threshold of the condylar–C1 interval to maximize identification of patients at high risk for atlantooccipital dislocation using computed tomography

“…These principles are also relevant in adults. Recently, Martinez-del-Campo et al 8 found a CCI cutoff of 1.5 mm using a similar method of comparison in a cohort of 81 adult patients-59 without AOD and 22 with AOD.…”

Upper Cervical Spine Trauma: WFNS Spine Committee Recommendations

“…An MRI is recommended to assess the integrity of the craniocervical ligaments for determining the stability of OCF (level III recommendation). 6 The small amount of cases explains the variety of different treatment recommendations, ranging from conservative therapy with neck immobilization to surgical fusion (level III evidence). 7 In a retrospective study (n = 23), Byström et al, 8 using the Mueller classification, found no unstable patients.…”