Tethered Cord
Tethered cord syndrome is a neurological disorder caused by abnormal attachment of the spinal cord to the surrounding tissues, restricting its normal upward movement within the spinal canal as the spine grows and the body moves. Normally, the spinal cord ends at the L1-L2 level in adults and can move freely within the spinal canal. In tethered cord, abnormal fixation causes the cord to stretch excessively, leading to progressive neurological dysfunction. The condition can be congenital (present from birth) or acquired, and symptoms typically worsen over time if untreated.
What is it?
During normal development, the spinal cord and vertebral column grow at different rates. In infancy, the spinal cord extends the entire length of the spinal canal, but as children grow, the vertebral column grows faster than the spinal cord. By adulthood, the spinal cord typically ends at the L1-L2 vertebral level, with a bundle of nerve roots called the cauda equina extending below this point. This differential growth allows the spinal cord to move freely up and down within the spinal canal with flexion, extension, and normal body movements. In tethered cord syndrome, abnormal tissue attachments prevent this normal movement, causing the spinal cord to stretch during growth or movement, leading to ischemia (reduced blood flow), mechanical stress, and progressive neurological damage.
Tethered cord is classified as congenital or acquired. Congenital tethering occurs due to developmental abnormalities during embryonic formation of the neural tube and spine, often associated with conditions such as spina bifida occulta (incomplete closure of the vertebral arch), lipomyelomeningocele (fatty mass attached to the spinal cord), tight filum terminale (abnormally thick and inelastic cord anchoring the spinal cord), dermal sinus tracts (connections between skin and spinal canal), diastematomyelia (split spinal cord malformation), or myelomeningocele (severe form of spina bifida). Acquired tethering can develop after spinal surgery, trauma, infection, or spinal tumors that create scar tissue anchoring the cord. Congenital tethered cord may present in infancy, childhood, or remain asymptomatic until adolescence or adulthood when growth spurts or increased activity unmasks the problem. Risk factors for congenital forms include family history of neural tube defects and inadequate maternal folic acid intake during pregnancy.
Important to Know
Symptoms of tethered cord syndrome vary depending on age at presentation and severity of tethering. In infants and young children, signs may include skin abnormalities over the lower spine such as dimples, hairy patches, or hemangiomas; asymmetric leg strength or movement; foot or leg deformities including clubfoot or high arches; and bladder or bowel dysfunction. In older children and adults, symptoms typically develop gradually and include lower back pain that radiates to the legs, worsening with activity or prolonged standing; progressive leg weakness, numbness, or sensory changes; bladder dysfunction including urgency, frequency, incontinence, or incomplete emptying; bowel dysfunction including constipation or fecal incontinence; sexual dysfunction; progressive foot deformities or gait abnormalities; and scoliosis (spinal curvature) that may develop or worsen. Symptoms often worsen during growth spurts, pregnancy, or with activities that stretch the spine. Diagnosis is made through MRI of the spine, which shows the position of the conus medullaris (end of the spinal cord)—a low-lying conus below L2-L3 suggests tethering—and can identify the specific cause such as a thickened filum terminale, lipoma, or scar tissue. Urodynamic studies assess bladder function, which is often affected even when not clinically apparent. Treatment for symptomatic tethered cord is surgical detethering, where neurosurgeons carefully release the abnormal attachments while preserving neural function. Surgery aims to prevent further neurological deterioration rather than reverse existing deficits, making early intervention important. Outcomes depend on symptom severity and duration before surgery—patients with milder, shorter-duration symptoms tend to have better outcomes. Pain and bladder function often improve after surgery, though complete resolution is not guaranteed. Motor deficits may stabilize but rarely fully recover. Retethering can occur after surgery, particularly in children who continue growing, sometimes requiring repeat intervention. Without treatment, tethered cord syndrome typically causes progressive neurological deterioration, making timely diagnosis and intervention critical to preserving function and quality of life.