Imaging description

In a radiological study, termination of conus medullaris below L2 vertebral level is considered tethering of the cord. However, tethered cord syndrome (TCS) is the constellation of symptoms and signs of motor and sensory dysfunction that are caused by excessive traction and tension on the spinal cord [1]. A majority of cases with TCS are associated with anomalies in nervous system development and are related to spinal dysraphism. Completely intradural processes such as lipoma of filum terminale (Fig. 98.1), abnormal fibrous adhesions, and shortened filum terminale are also associated with tethered cord. They are sometimes known as primary TCS, with terms like tight filum, fatty filum, and filum terminale syndrome [1]. Closed spinal dysraphisms such as lipomyelomeningocele, diastematomyelia, neurenteric cyst, lumbosacral lipoma (Fig. 98.2), dermal sinus, and thickened filum terminale are increasingly associated with tethered cord [2]. Almost all children born with open spinal dysraphisms such as spinal meningoceles (Fig. 98.3), myelomeningocele (Fig. 98.4), and myeloschisis have tethered cord [3]. More recently, TCS has been broadened to include patients with tethering of cervical or thoracic cord, and also patients with increased tension on the lower cord, in spite of having a normal position of conus [1]. TCS is also been associated with diverse conditions including trauma, infection, and neoplasm.