Level of the conus in pediatric patients with skeletal dysplasia

Skeletal dysplasias are a heterogeneous group of disorders that affect bone development and can result in reduced vertebral body growth and short stature. The level of the conus medullaris is unknown in this population. The purpose of this review was to determine the level of the conus in a population of pediatric patients with skeletal dysplasia.

A retrospective chart review of a 7-year period was undertaken at a tertiary care pediatric hospital to identify patients in whom skeletal dysplasia had been diagnosed. Radiographs and MR imaging studies were evaluated to discern the level of the conus with respect to the bony vertebral column.

Four hundred sixty-seven patients with skeletal dysplasia were identified. One hundred eleven patients had quality MR images. Forty-seven different skeletal dysplasias were observed. The mean conus level was found at the L-1 vertebral body. No difference was noted with respect to the age of the patients or the type of skeletal dysplasia. Two patients (1.7%) had a conus level lower than L-2.

Skeletal dysplasia leads to abnormal bone formation and can result in short stature. The location of the conus with respect to the vertebral bodies appears to be stable at the L-1 level regardless of patient age or the type of skeletal dysplasia involved. However, the appearance of a low-level conus and associated tethered cord syndrome may be slightly increased in this population.