Nerve Biopsy in Pediatric Medicine

Pediatric Procedures Introduction Clinical Indications Procedure Details Interpretation Complications

Key Points

• Diagnostic tool for peripheral neuropathies and neuromuscular disorders
• Usually performed on sensory nerves
• Common sites: sural nerve, superficial peroneal nerve
• Requires careful patient selection and expertise
• Should be considered after non-invasive investigations

Overview

Nerve biopsy is a specialized diagnostic procedure involving the surgical removal of a peripheral nerve segment for histological, immunochemical, and ultrastructural examination. In pediatric practice, it serves as a valuable tool for diagnosing various neuromuscular disorders when less invasive methods prove inconclusive.

Clinical Indications

Primary Indications

• Suspected hereditary neuropathies
  • Charcot-Marie-Tooth disease
  • Hereditary sensory and autonomic neuropathies
  • Dejerine-Sottas syndrome
• Inflammatory neuropathies
  • Chronic inflammatory demyelinating polyneuropathy (CIDP)
  • Vasculitic neuropathy
  • Leprosy (in endemic areas)
• Storage disorders affecting peripheral nerves
• Unexplained progressive neuropathy

Preoperative Assessment

• Complete neurological examination
• Nerve conduction studies
• EMG findings
• Relevant blood investigations
• Genetic testing results (if applicable)
• MRI neurography (when indicated)

Procedure Details

Preparation

• Informed consent from parents/guardians
• Fasting requirements: 6 hours for solids, 2 hours for clear fluids
• Local anesthetic or general anesthesia based on age and cooperation
• Marking of biopsy site with ultrasound guidance

Surgical Technique

1. Position patient laterally for sural nerve biopsy
2. Surgical site preparation and draping
3. Longitudinal incision (3-4 cm) posterior to lateral malleolus
4. Careful dissection through subcutaneous tissue
5. Identification and isolation of nerve
6. Collection of 3-4 cm nerve segment
7. Proper specimen handling:
   • Fresh frozen sample for metabolic studies
   • Formalin-fixed sample for histology
   • Glutaraldehyde-fixed sample for electron microscopy
8. Careful closure in layers

Interpretation of Findings

Histological Examination

• Light microscopy findings:
  • Myelinated fiber density
  • Axonal degeneration
  • Demyelination patterns
  • Inflammatory infiltrates
  • Vasculitic changes
• Electron microscopy findings:
  • Ultrastructural changes in myelin
  • Axonal cytoskeleton abnormalities
  • Inclusions and storage materials

Disease-Specific Patterns

• CMT1: Onion bulb formations
• CMT2: Axonal degeneration
• CIDP: Segmental demyelination
• Vasculitis: Vessel wall inflammation
• Storage disorders: Specific inclusions

Complications and Post-Procedure Care

Potential Complications

• Immediate:
  • Bleeding
  • Infection
  • Local pain
• Long-term:
  • Permanent sensory loss in nerve distribution
  • Neuroma formation
  • Complex regional pain syndrome (rare)

Post-Procedure Care

1. Wound care instructions
2. Pain management protocol
3. Activity restrictions
4. Follow-up schedule
5. Warning signs to watch for

Further Reading

• Peripheral Nerve Biopsy - PMC Article
• NINDS Peripheral Neuropathy Information Page
• Washington University Neuromuscular Disease Center
• American Academy of Neurology Guidelines