What is the recommended anesthetic management for a patient undergoing excision of a thoracolumbar myelomeningocele?

Anesthetic Management for Excision of Thoracolumbar Myelomeningocele

The recommended anesthetic management for thoracolumbar myelomeningocele excision should include a multidisciplinary approach with careful preoperative assessment, appropriate monitoring, and a balanced anesthetic technique that prioritizes hemodynamic stability and adequate pain control. 1, 2

Preoperative Assessment and Preparation

• Evaluate for associated anomalies, particularly hydrocephalus (present in 67.4% of cases) and Chiari-II malformation (58.4%), which significantly increase perioperative risk 1
• Assess for renal abnormalities (present in 9% of cases) and electrolyte imbalances, especially in leaking myelomeningocele 1
• Check for scoliosis (present in 24.4% of cases), which may complicate positioning and airway management 1
• Screen for respiratory issues, including stridor, which may indicate brainstem compression from Chiari malformation 1
• Optimize any electrolyte imbalances and address hydration status before surgery 1

Intraoperative Management

Anesthetic Technique

• General anesthesia with endotracheal intubation is the preferred technique for airway protection 3
• Consider a balanced anesthetic approach using short-acting agents for rapid emergence and neurological assessment 3
• Propofol is recommended for induction, with sevoflurane or isoflurane for maintenance 3
• Avoid atracurium and mivacurium; rocuronium and vecuronium are safer options for muscle relaxation 3
• Fentanyl or remifentanil are preferred opioids for intraoperative analgesia 3

Monitoring

• Standard monitoring including ECG, pulse oximetry, non-invasive blood pressure, capnography, temperature, and neuromuscular monitoring 3
• Consider invasive arterial pressure monitoring for high-risk cases (extensive lesions, significant associated anomalies) 3
• Continuous core temperature monitoring is essential to maintain normothermia 3

Positioning and Temperature Management

• Careful positioning to avoid pressure on the myelomeningocele sac before repair 1
• Maintain normothermia (core temperature ≥36°C) with active warming for operations lasting longer than 30 minutes 3
• Avoid temperature extremes that could trigger complications 3

Fluid Management

• Ensure adequate intravascular volume with careful fluid administration 3
• Be prepared for potential rapid blood loss, with appropriate vascular access and blood products available 3
• Near-zero fluid balance should be targeted 3

Regional Anesthesia Considerations

• Consider supplemental regional anesthesia for postoperative pain management 3
• Ultrasound-guided continuous paravertebral block may be appropriate depending on the level of the lesion 3
• Caudal block may be contraindicated due to anatomical abnormalities 3

Postoperative Management

Pain Control

• Implement multimodal opioid-sparing analgesia combining paracetamol and NSAIDs 3
• Consider regional techniques when appropriate for the specific case 3
• Tailor analgesic regimen based on the extent of surgery and patient's neurological status 3

Respiratory Management

• Monitor closely for respiratory complications, which occur in approximately 11.1% of cases 1
• Ensure complete reversal of neuromuscular blockade before extubation 1
• Be prepared for postoperative ventilation, which may be required in up to 8.9% of children 1

Complications to Anticipate

• Cardiac problems (15.6% of cases) and respiratory issues (11.1%) are common intraoperative complications 1
• Higher risk of cardiac arrest (1.5%) in patients with associated Chiari-II malformation and hydrocephalus 1
• Monitor for CSF leak, infection, and pseudomeningocele in the postoperative period 1

Special Considerations

• Patients with thoracic level lesions have poorer outcomes compared to those with lumbar or sacral lesions 2
• Early surgical repair (within 24 hours of birth) is associated with better outcomes in neonates 2
• For older infants with unrepaired MMC, careful assessment of associated anomalies is critical 1

By following this structured approach to anesthetic management, the risk of perioperative complications can be minimized while optimizing outcomes for patients undergoing thoracolumbar myelomeningocele excision.