Tethered Cord Syndrome
Spinal cord traction injury from abnormal attachment to surrounding tissue
ICD-10: Q06.8 · systemic condition
Tethered cord syndrome (TCS) is a stretch-induced dysfunction of the spinal cord caused by abnormal fixation of the cord to surrounding tissue, restricting its normal upward movement within the spinal canal during growth and flexion. In the normally developed spine, the conus medullaris (the tapered lower end of the spinal cord) is located above the L1–L2 level in adults. In tethered cord, the conus is anchored too low — often by a thickened filum terminale, lipomyelomeningocele, dermal sinus, or surgical scar — causing traction that impairs cord blood flow and metabolism. Tethered cord may be congenital (present from birth, often associated with spina bifida occulta, sacral dimple, or cutaneous stigmata such as hairy patches over the lower spine) or acquired (post-surgical scarring). Children commonly present with progressive scoliosis, foot deformity (cavovarus foot), leg weakness, or deteriorating bladder function. Adults with occult tethered cord may present with low back and leg pain, sensory changes, or incontinence. Surgical untethering — releasing the adhesion, dividing the tight filum, or removing a lipoma — is the treatment for symptomatic tethered cord. Most patients stabilize or improve neurologically after surgery, though recovery depends on severity and duration of pre-operative deficits. The risk of re-tethering after surgery is approximately 10–20%.
Anatomy & Pathology
The spinal cord normally ends (the conus medullaris) at approximately the L1–L2 vertebral level in adults. A thin fibrous strand called the filum terminale anchors the conus to the coccyx, but under normal tension. In tethered cord syndrome, this filum is thickened, shortened, or infiltrated with fatty tissue — or an adjacent mass is adherent to the cord — causing abnormally high tension, especially during flexion of the spine.
Symptoms
- Low back and leg pain worsened by forward flexion or prolonged sitting
- Progressive leg weakness or spasticity
- Bladder dysfunction: urgency, frequency, retention, or recurrent UTIs
- Cutaneous stigmata over the lower spine: sacral dimple, hairy tuft, hemangioma, or skin tag
- Foot deformity (cavovarus foot) or progressive gait abnormality in children
- Progressive scoliosis, particularly left-thoracic or lumbar curves
- Deteriorating bladder urodynamics on serial assessment
Causes & Risk Factors
- Thickened or fatty filum terminale (filum lipoma) anchoring the conus below L2
- Lipomyelomeningocele or lipomyeloschisis — lipomatous mass attached to conus
- Prior spinal surgery with epidural scar formation causing re-tethering
- Dermal sinus tract extending from skin to cord
- Spina bifida occulta with intraspinal fibrous bands
Treatment Options
Conservative
- MRI surveillance with urodynamic testing for mild or asymptomatic cases to define baseline
- Bladder management program: timed voiding, intermittent catheterization for neurogenic bladder
- Physical therapy for gait dysfunction and lower extremity strengthening
Surgical
- Surgical untethering: microsurgical division of thickened filum terminale under intraoperative neuromonitoring
- Lipoma resection combined with untethering for lipomyelomeningocele
- Lysis of epidural adhesions for post-surgical re-tethering (higher risk of neurological injury)
When to see a spine specialist
Children with cutaneous stigmata over the lower spine, progressive scoliosis without a structural cause, new foot deformity, or worsening bladder function should be evaluated with MRI. Adults with new low back or leg pain plus bladder dysfunction should also be screened. Prophylactic untethering before symptoms develop is often recommended for growing children with confirmed low-lying conus.
Specialists Who Treat Tethered Cord Syndrome
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Search spine specialists →Frequently Asked Questions
Does every child with a low-lying conus need surgery?
Not necessarily. A conus at L2–L3 in a child with no symptoms and no associated anomaly may be observed. However, a symptomatic child, one with neurourological abnormalities on urodynamics, or one with progressive deficits generally warrants surgery regardless of exact conus level. The decision balances the progressive nature of neurological injury from ongoing traction against the surgical risks of cord injury during untethering.
What happens if tethered cord is not treated?
Without treatment, tethered cord typically causes progressive neurological deterioration — worsening bladder dysfunction, increasing leg weakness, and expanding sensory deficits — particularly during growth spurts in children or with activities that stretch the cord. Scoliosis may worsen. Once significant motor or bladder dysfunction is established, recovery after surgery is incomplete. This is why early intervention during a window of preserved function is strongly favored.
Can tethered cord come back after surgery?
Yes. Re-tethering from scar tissue formation occurs in approximately 10–20% of patients after untethering surgery. Symptoms of re-tethering are similar to initial presentation but may be more subtle. Patients require long-term follow-up with periodic MRI and urodynamic testing. Reoperation for re-tethering carries higher neurological risk due to scarring around the cord and is technically more demanding.