Is remifentanil (an opioid analgesic) suitable for use in scoliosis surgery?

Remifentanil for Scoliosis Surgery

Remifentanil is suitable and commonly used for scoliosis surgery, particularly when combined with multimodal analgesia and appropriate transition strategies to longer-acting opioids before emergence. 1, 2

Intraoperative Use

Remifentanil is frequently employed during pediatric and adolescent scoliosis surgery for several key advantages:

• Provides optimal conditions for neurophysiological monitoring during spinal instrumentation, which is critical for detecting potential spinal cord compromise 2, 3
• Enables rapid awakening for immediate postoperative neurological assessment, a crucial safety consideration in spinal surgery 2, 3
• Maintains hemodynamic stability when combined with ketamine infusion (1 mcg/kg/min), preventing the hypotension that can occur with remifentanil alone 1
• Does not interfere with electrophysiological monitoring of spinal cord function when used appropriately 1

The European Society for Paediatric Anaesthesiology recommends remifentanil at 0.05-0.3 mcg/kg/min for intraoperative use in children 4

Critical Hyperalgesia Concern

The primary limitation is remifentanil-induced hyperalgesia, which manifests as increased postoperative opioid requirements and pain:

• Recent systematic reviews suggest the hyperalgesia is mild and not clinically relevant, likely representing a reduced pain threshold rather than true hyperalgesia 5
• Studies in scoliosis patients demonstrate increased 24-hour morphine consumption (38 ± 17 mg) when remifentanil is used alone 1
• Pre-treatment with morphine (150 mcg/kg) does not prevent remifentanil-induced hyperalgesia 6

Evidence-Based Mitigation Strategies

Ketamine Co-Administration (Strongest Evidence)

• Combining ketamine infusion (1 mcg/kg/min) with remifentanil significantly reduces postoperative pain and opioid requirements 1
• Reduces 24-hour morphine consumption to 28 ± 10 mg (compared to 38 ± 17 mg with remifentanil alone) 1
• Provides hemodynamic stability and lower initial pain scores in PACU 1

Methadone Addition

• Methadone 0.1 mg/kg IV over 15 minutes decreases perioperative opioid requirements (0.26 ± 0.10 mg/kg vs 0.34 ± 0.11 mg/kg) 2
• The benefit is primarily intraoperative, but given remifentanil's hyperalgesia potential, adjunctive methadone appears warranted 2

Magnesium

• Magnesium (50 mg/kg bolus followed by 10 mg/kg/h infusion) showed no benefit in reducing opioid requirements or pain scores in scoliosis surgery 2

Mandatory Transition Strategy

Never rely on remifentanil for postoperative analgesia—its ultra-short duration requires alternative analgesics before discontinuation:

• Administer a longer-acting opioid toward the end of surgery to prevent a gap between intra- and postoperative analgesia 5, 4
• Typical options include morphine, hydromorphone, or fentanyl given before emergence 1, 2
• The European Society for Paediatric Anaesthesiology emphasizes this transition is essential to avoid analgesic gaps 5

Postoperative Management Implications

Patients receiving intraoperative remifentanil have different ICU admission needs:

• Young, healthy idiopathic scoliosis patients receiving remifentanil (vs. morphine) and undergoing posterior fusion can be successfully managed in regular wards 3
• Remifentanil use correlates with earlier extubation compared to long-acting opioids like morphine (OR 17.91 for late extubation with morphine) 3
• ICU admission should still be considered for neuromuscular scoliosis, patients with comorbidities, or anterior/combined fusion approaches 3

Optimal Multimodal Regimen

Remifentanil should be avoided or used cautiously when comprehensive multimodal analgesia is available:

• One case series successfully omitted remifentanil entirely to avoid hyperalgesia, using dexmedetomidine, ketamine, and dexamethasone infusions with bilateral erector spinae plane blocks 7
• This approach resulted in minimal emergence pain and transition to oral analgesia on postoperative day 1 7
• When remifentanil is used, always combine with ketamine, dexamethasone, and consider methadone to minimize hyperalgesia 1, 2, 7

Common Pitfalls to Avoid

• Do not use remifentanil as a sole anesthetic without multimodal adjuncts—this maximizes hyperalgesia risk 1, 2
• Do not assume remifentanil provides any postoperative analgesia—it has no long-term analgesic effects 4
• Do not attempt to prevent hyperalgesia with pre-treatment morphine—this strategy is ineffective 6
• Do not forget to administer longer-acting opioids before discontinuing remifentanil—this creates dangerous analgesic gaps 5, 4