Providing effective analgesia after spinal fusion for idiopathic scoliosis remains a challenge with significant practice variation existing among high volume spine surgery centers. Even in the era of multimodal analgesia, opioids are the primary analgesics used for pain control after pediatric scoliosis surgery, but have multiple known adverse effects. The erector spinae plane block (ESPB) is a newly described fascial plane block performed by injecting local anesthetic between the erector spinae muscle and the transverse process. Additionally, there are case reports describing the ESPB as part of a multi-modal analgesic plan in adult degenerative spine surgery as well as adult spinal deformity surgery, demonstrating effective analgesia and no clinical motor blockade. Although it is known that the inflammatory reaction plays a crucial role in the mechanism of acute pain after major surgery, the effectiveness of the current regional approach on inflammatory response is not well studied.

Inclusion Criteria:

• ASA I-III
• Diagnosed with Idiopathic scoliosis
• Undergoing single-stage posterior spinal instrumentation and fusion

Exclusion Criteria:

• Thorascopic tethering procedure
• Two-stage procedure
• Abnormal developmental profile
• Congenital/neuromuscular scoliosis
• Requiring PICU admission
• Known allergy to lidocaine
• Known cardiac, renal or liver disease or dysfunction
• Pre-existing pain complaints, i.e. on regular analgesic medications
• Current psychiatric diagnosis, e.g. anxiety, depression, eating disorder, defined according to DSM criteria.
• Requiring non-standard post-op pain management
• Any history of seizures
• Unplanned staged procedure
• Weight < 5th centile or > 85th centile for age
• Porphyria