What is tethered cord syndrome?

Tethered Cord Syndrome

Tethered cord syndrome (TCS) is a neurological disorder characterized by abnormal stretching and fixation of the spinal cord to surrounding tissues, causing progressive neurological deterioration due to increased tension on the spinal cord with growth and movement. 1

Clinical Manifestations

Age-Dependent Presentation

• Infants: Often asymptomatic, primarily recognized through associated cutaneous abnormalities 1
• Children: Progressive symptoms develop as they grow:
  • Pain (back and/or leg)
  • Sensorimotor disturbances of lower limbs
  • Bowel and bladder dysfunction
  • Progressive musculoskeletal deformities 1
• Adolescents/Adults: May have history of subtle abnormalities dating back to childhood with sudden worsening after stretching events (childbirth, falls, sports injuries) 1

Key Clinical Features

Neurological Symptoms

• Pain: Varies from dull and aching to sharp, lancinating, or electrical; may be exacerbated by flexion/extension of spine 1
• Motor deficits: Present in up to 63% of patients 2
  • Muscle weakness (especially distal legs)
  • Gait disturbances
  • Athletic difficulties
  • Muscle atrophy with "saber shins" (may be misdiagnosed as Charcot-Marie-Tooth syndrome)
• Sensory deficits: Present in 61% of patients 2
  • Usually start distally in legs and progress proximally
  • Sometimes present as "suspended" sensory loss

Urologic Dysfunction

• Present in 56% of patients 2
• Manifestations vary by age:
  • Infants: Urinary tract infections, occasional urinary retention
  • Toilet-trained children: Secondary urinary incontinence, fecal incontinence, constipation
  • Older children/adolescents: Urgency, urge incontinence, stress incontinence, enuresis, frequency, nocturia 1
• Urodynamic studies may show:
  • Lower motor neuron dysfunction: Enlarged bladder with detrusor underactivity and external urethral sphincter denervation
  • Upper motor neuron dysfunction: Small, thick-walled bladder with detrusor overactivity and detrusor-sphincter dyssynergia 1

Orthopedic Manifestations

• Present in up to 75% of patients with spinal dysraphism 1
• Progressive scoliosis
• Exaggerated lumbosacral lordosis
• Foot deformities
• Leg length discrepancies 1

Cutaneous Markers

• High-risk markers: Infantile hemangiomas overlying lumbosacral spine, atretic meningocele
• Intermediate-risk markers: Capillary vascular malformations (port wine stains, nevus flammeus simplex) in midline/juxta-midline lumbosacral regions
• Other markers: Dermal sinus tracts, hairy patches, skin appendages, subcutaneous lipomas 1

Diagnosis

• MRI is essential for diagnosis, especially in patients with:
  • Bowel and bladder dysfunction
  • Lower limb upper motor neuron signs
  • Sacral dimple 1
• Urodynamic testing provides information about sacral spinal cord involvement 1
• Plain radiographs may reveal bony abnormalities of spine 1

Treatment

• Surgical untethering is indicated in patients with progressive or new-onset symptoms attributable to TCS 3
• Surgical goals:
  • Release the tethering structure to relieve chronic tension on the cord
  • Pain relief (achieved in almost all cases)
  • Stabilization of neurological function (improvement often seen)
  • Halt progression of scoliosis 3
• Alternative surgical approach: Spine-shortening osteotomy (SSO) for complex cases or revision surgeries 4

Prognosis and Outcomes

• Early surgical intervention is associated with improved outcomes 3
• Pain is the symptom most responsive to surgery (81% improvement rate) 2
• Long-standing orthopedic deformities may not improve despite successful untethering 1
• Lifelong surveillance is essential component of management 5

Associated Conditions

TCS can be associated with various syndromes and conditions:

• Spinal dysraphism
• 22q11.2 deletion syndrome 1
• KBG syndrome (caused by variants in ANKRD11 gene) 6
• Anorectal malformations (10-52% association) 1
• LUMBAR syndrome 1

Clinical Pitfalls and Caveats

• TCS may be misdiagnosed as other conditions (e.g., Charcot-Marie-Tooth syndrome)
• Symptoms can be subtle and progressive
• Sudden neurological deterioration may occur after stretching events
• Early recognition and treatment are crucial to prevent irreversible neurological damage
• Benefits of surgery in asymptomatic patients remain debated 3