Ana Maria Gaca MD, Presenter: Nothing to Disclose

George S. Bisset MD, Abstract Co-Author: Nothing to Disclose

In the setting of trauma, it is uncertain whether minor anterior wedging at the thoracolumbar junction (TLJ) is the result of trauma or a normal developmental variant. We propose that anterior wedging of vertebral bodies at the TLJ can be seen in children as a normal variant, rather than resulting from trauma.

An IRB approved, retrospective review was performed of all pediatric abdomen/pelvis CTs performed from January, 2004-March, 2006. All children with a history of trauma, malignancy and steroids were excluded. 20 CTs were randomly selected and divided into 5 arbitrarily selected age groups: < 3 yrs, 4 – 7, 8 – 11, 12 – 14, and 15 – 17. Sagittally reformatted images were obtained of the TLJ. The anterior and posterior heights of the T10 through L3 vertebral bodies were measured to determine the anterior:posterior vertebral body height ratio (A:P ratio). Measurements were performed independently by 2 pediatric radiologists (average experience 12.5 years) at two separate settings 4 weeks apart, to confirm inter- and intra-observer variability. Measurements were then performed on 80 additional patients, for a total of 100 (20/age group). A:P ratios were analyzed by means of repeated measures of analysis of variance, using reader, subject, age group, vertebral body and interaction of age/vertebral body as random effects.

Mean A:P ratio for the vertebral bodies from T10 to L3 ranged from 0.977 to 1.008. While age was statistically significant with respect to the absolute vertebral body measurements, it was not statistically significant with respect to A:P ratio (p>0.4). Using estimated percentiles, 95% of the population has an A:P ratio that is greater than 0.910.

95% of children have an A:P ratio of at least 0.910, with mean A:P ratios ranging between 0.977 and 1.008. This suggests anterior vertebral body height loss resulting in an A:P ratio less than 0.910 is not a normal variant, and should raise the possibility of vertebral body injury. Because age was not statistically significant, this value can be used for all pediatric age groups, and should represent the norm for assessing for vertebral compression fractures.

Anterior loss of vertebral body height resulting in an anterior to posterior ratio less than 0.910 is not a normal variant, but should raise the possibility of vertebral body injury.

Gaca, A, Bisset, G, Evaluation of Wedging of Lower Thoracic and Upper Lumbar Vertebral Bodies in the Pediatric Population.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6017363.html