What is the recommended opioid regimen for Total Intravenous Anesthesia (TIVA) in scoliosis surgery?

Opioid Recommendation for TIVA in Scoliosis Surgery

For TIVA in scoliosis surgery, use remifentanil infusion at 0.05-0.3 mcg/kg/min combined with ketamine 0.5 mg/kg bolus followed by 0.1-0.2 mg/kg/h infusion, avoiding remifentanil monotherapy to prevent opioid-induced hyperalgesia while maintaining hemodynamic stability and adequate postoperative analgesia. 1, 2

Recommended Opioid Regimen

Primary Approach: Remifentanil-Ketamine Combination

• Remifentanil: Administer as continuous infusion at 0.2 mcg/kg/min (range 0.05-0.3 mcg/kg/min) 1, 2
• Ketamine co-administration: Give 0.5 mg/kg bolus at induction, followed by continuous infusion at 1 mcg/kg/min (equivalent to 0.1-0.2 mg/kg/h) 1, 2
• This combination provides superior hemodynamic stability compared to remifentanil alone, with significantly lower first pain scores upon PACU arrival 2

Critical Evidence Supporting This Approach

The combination of remifentanil-ketamine in pediatric scoliosis surgery demonstrates:

• Reduced postoperative opioid consumption: 28 ± 10 mg morphine in first 24h versus 38 ± 17 mg with remifentanil alone 2
• Hemodynamic stability: Prevents the significant decreases in heart rate and blood pressure seen with remifentanil monotherapy 2
• Preserved neuromonitoring: Does not interfere with electrophysiological monitoring during surgery 2
• Delayed time to first PCA demand: Indicating better immediate postoperative analgesia 2

Alternative Opioid Options

Fentanyl-Based Regimens

If remifentanil is unavailable, use short-acting opioids:

• Fentanyl: 1-2 mcg/kg boluses as needed 1
• Sufentanil: 0.5-1 mcg/kg bolus with continuous infusion at 0.5-1 mcg/kg/h 1
• Alfentanil: 10-20 mcg/kg boluses 1

Dosing Considerations for Fentanyl

When using fentanyl for wake-up testing during scoliosis surgery, maintain effect-site concentrations of 1-2 ng/mL at time of wake-up to balance rapid emergence with adequate analgesia 3

Essential Adjunctive Medications

Mandatory Co-Analgesics for Opioid-Sparing

• Dexmedetomidine: 0.5-1 mcg/kg bolus, then 0.2-0.7 mcg/kg/h infusion 1, 4

  • Reduces opioid requirements significantly
  • Provides sympatholysis and sedation

• Dexamethasone: 0.15-0.25 mg/kg (maximum 0.5 mg/kg) 1, 4

  • Reduces postoperative swelling and inflammation
  • Improves overall analgesia

• Intravenous lidocaine: 1.5 mg/kg bolus, then 1.5 mg/kg/h infusion until end of procedure 1

  • Provides additional analgesia and reduces opioid needs

Critical Pitfalls to Avoid

Remifentanil-Induced Hyperalgesia

Do not use remifentanil as monotherapy - this is the most important caveat. High-dose remifentanil without ketamine or other NMDA antagonists can cause opioid-induced hyperalgesia, increasing postoperative pain and opioid consumption 4, 2

Dosing Errors

• Avoid morphine boluses of 25-100 mcg/kg intraoperatively in children undergoing major spine surgery - these are too variable and unpredictable 1
• Do not use nitrous oxide with volatile agents, as it increases PONV and delays bowel function 1

Anesthetic Maintenance Strategy

Propofol TIVA Protocol

• Induction: Propofol bolus for rapid onset 1
• Maintenance: Target-controlled infusion of propofol 1
• Advantages: Reduced PONV compared to volatile agents, which is particularly important in scoliosis surgery 1

Monitoring Requirements

• Neuromuscular monitoring: Mandatory with quantitative monitoring to ensure train-of-four ratio ≥ 0.90 before extubation 1
• BIS monitoring: Consider in elderly patients to avoid excessive anesthetic depth and reduce delirium risk 1
• Continuous vital signs: Pulse oximetry, capnography, blood pressure, heart rate 5

Regional Anesthesia Integration

Erector Spinae Plane (ESP) Blocks

Consider bilateral bi-level ESP blocks (at T4 and T10) performed before incision as part of multimodal approach:

• Provides pre-emptive regional analgesia for extensive multi-level spine surgery 4
• Allows transition to oral analgesia on postoperative day 1 with minimal opioid requirements 4
• Has additive and potentially synergistic benefits when combined with systemic opioid-sparing strategies 4

Postoperative Transition

Immediate Postoperative Period

• Breakthrough pain in PACU: Fentanyl 0.5-1.0 mcg/kg titrated to effect 1
• Alternative: Morphine 25-100 mcg/kg depending on age, titrated to effect 1
• Ketamine: 0.25-0.5 mg/kg for breakthrough pain 1

First 24 Hours

• Transition to multimodal oral analgesia as soon as possible 4
• Continue scheduled acetaminophen and NSAIDs (if not contraindicated) 1, 5
• Reserve opioids for severe breakthrough pain only 5

Special Considerations for Pediatric Patients

The evidence base for scoliosis surgery is predominantly in pediatric and adolescent populations (ages 8-18 years) 2, 6, 3. The remifentanil-ketamine combination has been specifically validated in this age group with excellent safety and efficacy profiles 2.