Coronal Vertebral Dislocation Due to Congenital Absence of Multiple Thoracic and Lumbar Pedicles: Report of Three Cases, Review of Literature, and Role of Intraoperative CT Navigation.

Abstract

Case report OBJECTIVE: To present three cases of coronal vertebral dislocation due to congenital multiple thoracic and lumbar pedicle agenesis. Congenital pedicle agenesis is an uncommon condition and is frequently identified as an incidental finding on diagnostic imaging in asymptomatic individuals. This agenesis is frequently limited to a single level and is commonly seen in the cervical and lumbar spine. We report three patients who presented with multiple thoracic and lumbar pedicle agenesis resulting in coronal vertebral dislocation. The patients presented with progressive kyphoscoliosis deformity. Identification of this malformation on conventional radiographs is difficult, and computed tomographic (CT) scan with 3D reconstruction provides a better delineation of the deformity. Computed tomography showed complete absence of pedicles and dissociation of anterior column from the posterior column, resulting in coronal vertebral dislocation. Magnetic resonance imaging confirmed the absence of pedicles and decreased anteroposterior diameter, causing canal stenosis. Two patients were treated by spanning internal fixation, partial deformity correction, and posterior fusion, with satisfactory results. Coronal vertebral dislocation can be easily missed on plain radiograph because many patients with severe scoliotic deformity have thin or sclerotic pedicles. Computed tomography is essential to demonstrate these anomalies. It is important to recognize pedicle aplasia early to prevent rapid progression of deformity and neurologic deficit.