Spina Bifida Occulta with Bilateral Spondylolysis at the Thoracolumbar Junction Presenting Cauda Equina Syndrome

Abstract

Several reports have described the coexistence of spina bifida occulta (SBO) and spondylolysis, but the majority of defects occur at L5. No report has described the coexistence of SBO and spondylolysis at the thoracolumbar junction. We report a case of SBO with spondylolysis at L1, presenting cauda equine syndrome. A 37-year-old man presented with a gait disorder as a result of bilateral motor weakness of the lower extremities. A plain radiograph showed local kyphosis at L1-2 as a result of severe degenerative change and wedging of the vertebral body at L1. Magnetic resonance imaging (MRI) revealed degenerative disc changes and severe canal stenosis at L1-2. Computed tomography (CT) revealed SBO and spondylolysis at L1. He was diagnosed with cauda equina syndrome related to SBO and spondylolysis at L1. Posterior interbody fusion and decompression at L1-2 were performed. After surgery, his muscle power recovered to normal strength. The possible mechanisms in this case are the strain on anterior elements as a result of disruption of the posterior elements due to SBO and spondylolysis. The coexistence of SBO and spondylolysis at the thoracolumbar junction might induce at-risk status of increased strain to the anterior elements that may cause cauda equina syndrome.

Spina Bifida Occulta

“…When in doubt, it is always most appropriate to refer to an orthopaedic spine specialist or neurosurgeon. Given the more common scenario, the advanced practice provider can provide reassurance to their patients that the finding of spina bifida occulta is customarily only incidental, with research showing there is no increased risk of injury from even higher intensity activities (Albano et al, 1996; Avrahami et al, 1994; Babbi et al, 2014; CDC, 2011; Mataki et al, 2020; Rajpal et al, 2007; Yun et al, 2016).…”

“…This malformation occurs with the greatest incidence in the lower lumbar segments but has been reported in cervical and thoracic levels of the spine as well. As the name “occulta” implies, the defect is usually hidden under the skin, typically with no other discernable signs or symptoms, and diagnosis is most often made incidentally (Centers for Disease Control and Prevention [CDC], 2011; Eubanks & Cheruvu, 2009; Mataki et al, 2020; National Institute of Neurologic Disorders and Stroke, 2021; Yun et al, 2016).…”