Occurrence and Significance of Odontoid Lateral Mass Interspace Asymmetry in Trauma Patients

Abstract

OLMI asymmetry should only be investigated by CT scans of the head in optimal position and with the threshold value of 1.0 mm. OLMI asymmetry should not be used alone as a sign of a cervical spine lesion. MRI should be performed if: (1) the physician has a high degree of suspicion of a cervical spine lesion; (2) OLMI asymmetry was demonstrated on a technically adequate CT scan; (3) clinical symptoms persist in patients with OLMI asymmetry when no acute MRI was performed.

Asymmetry of the Odontoid Lateral Mass Interval in Pediatric Trauma CT: Do We Need to Investigate Further?

“…In a study by Wolansky et al, 8 an asymmetry Ͼ3 mm was found to be abnormal in adults. On the other hand, Billmann et al 12 did not find a significant correlation between OLMI asymmetry and traumatic injury in adults. It seems that on the basis of our results and prior studies, a division of normal and abnormal based on OLMI asymmetry alone cannot be applied.…”

“…[6][7][8][9][10][11][12] It is thought to arise from anatomic variation, head rotation, and muscle spasm. Nevertheless OLMI asymmetry might also imply ligamentous injury or atlantoaxial rotational fixation/subluxation at the C1-C2 level which, if present, could potentially lead to a catastrophic sequela.…”

Inter-examiner reliability of radiographic measurements from Open-mouth lateral bending cervical radiographs

“…Several studies have revealed issues with the reliability of image interpretation, as well as technical difficulties with patient positioning and image acquisition when performing these sequences [8,9,[11][12][13]33]. Lastly, this imaging technique may be inaccurate unless optimal technique is employed, necessitating expertise by involved staff [11,13,26]. These conflicting data highlight the need to investigate complementary imaging techniques which may reveal occult CCJ injury; additional methods of dynamic radiography, as described in this study, may provide that complement.…”

“…It has been shown that static CT imaging often reveals OLMI asymmetry in asymptomatic patients [25]. One recent study found that OLMI as measured on static CT imaging lacks sensitivity and specificity in detecting ligamentous injury, unless optimal technique is employed [26]. When measured on odontoid open-mouth radiographs, OLMI asymmetry may be an indicator of serious occult injury such as rotary subluxation or fracture [27].…”

Diagnostic Benefit of MRI for Exclusion of Ligamentous Injury in Patients with Lateral Atlantodental Interval Asymmetry at Initial Trauma CT

“…Neben einer Verletzung der stabilisierenden atlantodentalen Ligamente wie der Ligamenta alaria oder des Ligamentum transversum atlantis, welche der CT-Bildgebung entgehen können, mit hieraus resultierender Subluxations-oder Luxationsstellung des Dens axis im Atlantodentalgelenk, sind auch anatomische Normvarianten oder vorausgegangene Verletzungen der HWS als Ursache möglich . Die Kopfrotation, die Kopfneigung oder auch muskuläre Anspannung können ebenfalls Einfluss auf das laterale atlantodentale Intervall haben und dadurch zu einer lateralen Dens axis Deviation auch bei einem Normalkollektiv führen Chen et al 2011;Billmann et al 2013). Hierdurch ist alleine auf Basis des CT morphologischen Befundes eine Differenzierung zwischen einer pathologischen und einer physiologischen lateralen Dens axis Deviation nur schwer möglich ist.…”