Tethered Cord Syndrome

Tethered cord syndrome occurs when the spinal cord is abnormally attached to surrounding structures — most often the base of the spinal canal — restricting its normal movement and placing mechanical tension on the cord. This traction injury can disrupt blood flow and nerve function, causing a progressive spectrum of neurological, urological, and orthopedic problems.

Tethered cord syndrome has important connections to several other spinal conditions. Post-surgical scar tissue causing tethering is a form of Arachnoiditis, and cord tethering is one of the recognized causes of Syringomyelia — a fluid-filled cavity within the cord that develops under traction. In children, the resulting asymmetric muscle weakness frequently leads to Scoliosis, and severe cases can produce symptoms resembling Cauda Equina Syndrome.

Causes

Congenital abnormalities.

The most common cause is a thickened or shortened filum terminale — the thin fibrous strand that anchors the tip of the spinal cord — which prevents the cord from moving freely within the canal. Other congenital causes include spina bifida (particularly with myelomeningocele repair), lipomyelomeningocele, dermal sinus tracts, and split cord malformations (diastematomyelia).

Acquired causes

Tethered cord can also develop after spinal surgery or trauma due to scar tissue formation (arachnoiditis) that adheres the spinal cord to surrounding structures. Spinal tumors such as lipomas, dermoids, or epidermoids can also tether the cord.

Symptoms

In children, symptoms often become apparent during growth spurts when the spinal cord experiences increased traction. These include lower back and leg pain, leg weakness or changes in gait, scoliosis, foot deformities, and bladder or bowel dysfunction. In adults, tethered cord may present insidiously with chronic lower back pain, leg pain or weakness, sensory changes in the lower extremities, and progressive bladder dysfunction. Skin findings over the lower spine — such as a tuft of hair, dimple, birthmark, or fatty mass — may indicate an underlying spinal abnormality.

Diagnosis

A lumbar spine MRI is the primary diagnostic tool, identifying a low-lying conus medullaris (the tapered end of the spinal cord) below the L1–L2 level, a thickened or fatty filum terminale, or other structural abnormalities causing tethering. In some cases of occult tethered cord, the conus position may be normal but the filum is abnormally thick or fatty. Urodynamic studies are important to assess bladder function, as urological dysfunction is often the most sensitive indicator of cord tethering.

Classification

Tethered cord syndrome is categorized based on the underlying structural cause of tethering.

• Tight filum terminale: Thickened or fatty filum restricting cord movement — the most common form in otherwise normal-appearing spines.
• Lipomyelomeningocele: Fatty mass tethering the spinal cord, often associated with spina bifida occulta.
• Post-surgical tethering: Scar tissue adhesion following prior spinal surgery or myelomeningocele repair.
• Split cord malformation: The cord is divided by a bony or fibrous spur, tethering each half.

Treatments

The primary treatment for symptomatic tethered cord syndrome is surgical detethering to release the tension on the spinal cord and prevent further neurological deterioration. Intervention is typically recommended before irreversible cord damage occurs.

In children with progressive symptoms or significant urological, orthopedic, or neurological findings, early surgical intervention is strongly favored to allow the best chance of neurological recovery and to prevent worsening during growth.

Surgical detethering: The procedure involves microsurgical release of the structure tethering the cord — sectioning the tight filum terminale, excising lipomas, releasing scar tissue, or removing tethering tumors. This is performed with intraoperative neurophysiological monitoring to protect spinal cord function during surgery. Outcomes are generally favorable, with stabilization or improvement of symptoms in the majority of patients.

Post-surgical monitoring

Long-term follow-up with repeat MRI and urological assessment is essential, as re-tethering can occur over time — particularly in patients with lipomyelomeningocele or following myelomeningocele repair. Additional surgical intervention may be needed if symptoms recur.

Related Spine Conditions

• Syringomyelia
• Arachnoiditis
• Scoliosis
• Cauda Equina Syndrome
• Spinal Tumors
• Back to all Spine Conditions