What is the likelihood and management of tethered cord syndrome due to infection and trauma?

Likelihood and Management of Tethered Cord Syndrome Due to Infection and Trauma

Tethered cord syndrome is rarely caused by infection or trauma as primary etiologies; it is predominantly a congenital condition related to dysraphic malformations, with secondary tethering possible after spinal surgery, trauma, or infection. 1

Etiology and Pathophysiology

Tethered cord syndrome (TCS) occurs when the spinal cord is abnormally fixed to surrounding structures, preventing normal movement and causing stretching of the cord. The primary causes include:

1. Congenital causes (most common):

   • Dysraphic malformations (myelomeningocele, lipomyelomeningocele)
   • Dermal sinus tracts
   • Tight filum terminale
   • Split cord malformations

2. Secondary causes (less common):

   • Post-surgical adhesions following repair of spinal dysraphism
   • Post-traumatic scarring
   • Post-infectious arachnoiditis

Likelihood of Tethered Cord Due to Infection and Trauma

The likelihood of tethered cord syndrome developing primarily from infection or trauma is relatively low compared to congenital causes. However, these factors can contribute to:

• Secondary tethering: After initial surgical repair of congenital malformations
• Retethering: In previously detethered patients

Specific mechanisms include:

• Trauma-induced arachnoid adhesions
• Post-infectious inflammatory changes leading to scarring
• Surgical site infections causing fibrosis and adhesions (occurring in approximately 6-44% of cases with open fractures) 1

Clinical Presentation

Signs and symptoms vary by age:

In Children:

• Cutaneous stigmata (dimples, hemangiomas, hairy patches)
• Progressive orthopedic deformities (75% of patients) 1
• Urologic dysfunction (incontinence, recurrent UTIs)
• Motor and sensory deficits in lower extremities
• Gait abnormalities

In Adults:

• Back/leg pain (often the presenting symptom)
• Progressive neurological deficits
• Bladder/bowel dysfunction
• Sensory changes
• Pain that worsens with flexion/extension 2

Diagnostic Approach

1. MRI of the spine: Gold standard with moderate strength of evidence for diagnosing tethered cord, showing medium to high sensitivity and specificity 3

   • Look for low-lying conus medullaris (below L1-L2)
   • Thickened filum terminale
   • Intradural lipomas
   • Scarring/adhesions

2. When infection/trauma is suspected:

   • Look for evidence of arachnoid scarring
   • Evaluate for post-inflammatory changes
   • Assess for post-surgical adhesions

3. Additional studies:

   • Urodynamic testing to assess bladder function
   • Plain radiographs for associated bony abnormalities

Management Algorithm

1. Asymptomatic Patients with Radiographic Tethering

• If due to congenital causes: Consider prophylactic surgery (evidence suggests stability of neurologic status over time) 3, 4
• If due to post-infectious/traumatic causes: Observation with regular neurological monitoring

2. Symptomatic Patients

• Surgical detethering is the primary treatment:

  • Microsurgical release of tethered cord
  • Sectioning of filum terminale if thickened
  • Cutting arachnoid and fibrous bands
  • Protection of nerve rootlets 5
  • Use of multimodality intraoperative neurophysiological monitoring 6

• Post-infectious cases: May require more extensive lysis of adhesions

• Post-traumatic cases: May require more complex reconstruction

3. Post-Surgical Management

• Antibiotic prophylaxis: For 48-72 hours post-surgery to prevent infection 1
• Early mobilization: To prevent new adhesions
• Regular follow-up: To monitor for retethering

Expected Outcomes

Surgical outcomes vary by presentation:

• Pain improvement: 78-83% of patients 6
• Motor function: Better improvement than sensory deficits 6
• Bladder function: Improvement in approximately 50% of patients 6
• Overall stabilization or improvement: In 90% of patients 6

Complications and Pitfalls

1. Surgical complications:

   • CSF leakage (most common complication, 9 of 60 patients in one series) 6
   • Surgical site infection
   • Meningitis
   • Neurological deterioration (rare)

2. Clinical pitfalls:

   • Delayed diagnosis in adults due to attribution of symptoms to other causes
   • Failure to recognize progressive symptoms requiring intervention
   • Inadequate imaging (CT without MRI)
   • Overlooking subtle neurological deterioration

3. Management pitfalls:

   • Delaying surgery in progressive cases
   • Inadequate surgical release
   • Failure to use neurophysiological monitoring during surgery

Special Considerations for Infection/Trauma-Related Tethering

1. Timing of surgery:

   • In post-infectious cases: Allow resolution of acute inflammation
   • In post-traumatic cases: Stabilize other injuries first

2. Surgical approach:

   • More extensive exposure may be needed
   • Higher risk of CSF leak and wound complications

3. Follow-up:

   • More frequent monitoring for retethering
   • Lower threshold for reimaging with new symptoms

Conclusion

While tethered cord syndrome is predominantly a congenital condition, secondary tethering can occur following infection or trauma. Early diagnosis with MRI and prompt surgical intervention in symptomatic patients offers the best chance for preventing progressive neurological deterioration.