Occipitocervical measurements: correlation and consistency between multi-positional magnetic resonance imaging and dynamic radiographs.

PURPOSE: To evaluate the reliability and validity of the multi-positional magnetic resonance imaging in measuring occipitocervical parameters using the standard cervical dynamic radiographs as a reference. METHODS: Patients were included if they underwent both dynamic radiograph and cervical multi-positional MRI within a 2-week interval from January 2013 to December 2016. Twelve occipitocervical parameters were measured on both image modalities in all positions (neutral, flexion and extension): Posterior Atlanto-Dental Interval, Anterior Atlanto-Dental Interval (AADI), Dens-to-McRae distance, Dens-to-McGregor distance, Occipito-atlantal Cobb angle (C01 angle), Occipito-axis Cobb angle (C02 Cobb angle), Atlas-axis Cobb angle (C12 angle), Redlund-Johnell, Modified Ranawat, Clivus canal angle, Occiput inclination, and Occiput cervical distance. Pearson correlation and linear regression analysis were used to evaluate the correlation of both modalities for each parameter. A p value of < 0.05 was considered statistically significant. RESULTS: Cervical images of 70 patients were measured and analyzed. There was a significant positive correlation between dynamic X-ray and multi-positional MRI for all parameters (p < 0.05) except AADI. Dens-to-McGregor distance and Redlund-Johnell parameter demonstrated a very strong correlation in the neutral position (r = 0.72, r = 0.79 respectively) and moderate to very strong correlation(r > 0.4) for Modified Ranawat, Clivus canal angle, C02 Cobb angle and C02 distance in all neck position. The intra-class correlation (ICC) of intra- and inter-observer showed good to excellent reliability, and ICCs were 0.67-0.98. CONCLUSIONS: Multi-positional MRI can be a reliable imaging option for diagnosis of occipitocervical instability or basilar invagination compared to standard dynamic radiographs.

Acute traumatic unilateral cervical C4-C5 facet dislocation in pediatric toddlers.

BACKGROUND: The present study is to highlight the challenges in managing cervical spine injuries in toddlers (less than 4 years of age) without neurological deficit. Cases of unilateral cervical C4-C5 facet dislocation in toddlers are very rare. CASE PRESENTATION: A 3-year-old girl suffered cervical spine injury after a motor vehicle collision with unilateral C4-C5 facet dislocation without neurological deficit. Magnetic resonance imaging (MRI) showed no spinal cord injury, Frankel grade E. Initial management was cervical spine protection. Definite treatment and complication were discussed with the patient's parents before closed reduction maneuver with minerva cast was applied under sedation. The patient showed no complication after closed reduction and the cervical spine had aligned well in radiographs. The minerva cast was removed at 8 weeks, at which point neck muscle stretching rehabilitation program started. At one-year follow up, the child was asymptomatic, had full active cervical motion and good function. In radiographs, the cervical spine had normal alignment and was healed. CONCLUSIONS: Unilateral cervical facet dislocation in toddlers is very rare. Closed reduction maneuver and the minerva cast applied were optional in this case. The parents were highly satisfied with the effective treatment and outcome.

Kinematic evaluation of thoracic spinal cord sagittal diameter and the space available for cord using weight-bearing kinematic magnetic resonance imaging.

STUDY DESIGN: Retrospective kinematic MRI (kMRI) study. OBJECTIVE: To evaluate the dynamic changes of thoracic anterior and posterior space available for cord (SAC), and thoracic spinal cord in the dural sac in three positions. SETTING: Expert MRI, Bellflower California; and University of Southern California, in Los Angeles, USA. METHODS: A total of 118 patients (66 males and 52 females, mean age ( ± SD) of 45.6 ± 10.6 years) who underwent thoracic spine kMRI were evaluated from T4-5 to T11-12 in flexion, neutral, and extension positions. The anterior SAC, posterior SAC, and mid-sagittal thoracic cord diameter were measured at each level from T4-5 to T11-12. Inter- and intraobserver agreements were analyzed. RESULTS: The anterior SAC was significantly narrower in flexion position compared with other positions at T8-9 to T11-12 levels (p < 0.01). The T8-9 level had significantly wider posterior SAC in flexion and extension positions compared with the neutral position (p < 0.005). However, the posterior SAC at T9-10 was narrower in extension than the neutral position (p = 0.002). Thoracic spinal cord diameter significantly increased in flexion position when compared with the neutral position at T8-9, T9-10, and T11-12 levels (p < 0.005). CONCLUSIONS: Thoracic spinal cord had dynamic changes with positions. In flexion position, the thoracic cord at T8-9 and below tended to move anteriorly, getting closer to the vertebral body and intervertebral disc. The mid-sagittal diameter of the thoracic cord increased in flexion position at the levels below T8-9. In the presence of lesions in anterior epidural space, the risk of spinal cord compression is higher in flexion position, especially at levels below T8-9.

L4-L5 Total Dislocation with Cauda equina Syndrome: A Case Report.

Background: There are very few reports in the literature that describe total anterolateral fracture dislocation of L4 and L5. To present a case report of L4-L5 total dislocation with major neurological deficit and open fracture of left distal femur. Case Report: A 45-year-old Thai woman was transported to hospital with severe trauma, low back pain, a shallow lacerated wound on her back, and ecchymosis around waist and trunk. Closed reduction was initially performed and followed with posterior decompression, fusion, and instrumentation with pedicular screws and rod systems from L3-S1. Open reduction and internal fixation of distal femur was then performed. Conclusion: At 1-year follow-up, the patient could ambulate with left ankle-foot orthosis (AFO) using a walker.