Which pathology is MOST likely based on hypertonicity of the bilateral lower extremities, progressive scoliosis, low back pain, and sporadic urinary incontinence in an adolescent with spina bifida?

• A. Syringomyelia
• B. Tetralogy of Fallot
• C. Posterior cord syndrome
• D. Tethered cord syndrome

Answer: (D)

Progressive tethering of the spinal cord in a patient with spina bifida best fits this presentation. When the cord is abnormally attached (often from a low-lying conus with a thick filum or a lipoma), growth during adolescence creates traction on the neural elements. This traction leads to increasing motor signs—hypertonicity and UMN-type gait changes in the legs—and autonomic symptoms such as neurogenic bladder, which can manifest as sporadic urinary incontinence. Sc rolling scoliosis and back pain also commonly accompany tethered cord as the spine and cord are pulled out of alignment over time.

Syringomyelia would typically produce a different pattern, such as dissociated sensory loss (pain and temperature loss) in a cape-like distribution and may involve hand weakness if the syrinx extends cervically, rather than a classic combination of leg hypertonicity, scoliosis, and intermittent incontinence linked to spinal cord tethering in spina bifida. Tetralogy of Fallot is a heart defect with no direct relation to these spinal symptoms, and posterior cord syndrome would present with loss of proprioception and vibration rather than the predominant spasticity and bladder changes described.