Propofol + Remifentanil vs. Propofol + Dexmedetomidine in Adolescent Idiopathic Scoliosis Patients Having Spine Surgery

Patients with Adolescent Idiopathic Scoliosis may need surgery to correct their scoliosis. General anesthesia is required for this surgery, and a multimodal analgesic regimen using combinations of opioid and non-opioid medications is the standard of care. The purpose of this study is to compare two combinations of total intravenous anesthetic medications in children with Adolescent Idiopathic Scoliosis having posterior spinal fusion surgery.

Participants in the study will be randomly selected to receive either Propofol and Remifentanil or Propofol and Dexmedetomidine as their total intravenous anesthesia (TIVA). TIVA is favored over gas anesthesia because gas anesthesia can affect the neurological monitoring necessary for this surgery.

The first combination (Propofol + Remifentanil) is the most common one used for this surgery at our institution, and the second combination (Propofol + Dexmedetomidine) is more commonly used in adult spine surgery. Though Dexmedetomidine is not approved for pediatric use by the FDA, it is widely used in pediatric patients for procedural sedation and surgical anesthesia in the US and worldwide. Both anesthetic combinations are used safely in adult and pediatric patients at our institution.

Although remifentanil works fast and is an excellent pain medication during surgery, there are reports that it's use can cause increased pain sensitivity and greater need for narcotic pain medication after surgery. This phenomenon is known as opioid-induced hyperalgesia. The investigators hypothesize that avoiding the use of remifentanil in the TIVA by using dexmedetomidine could avoid OIH and thus result in superior postop pain control.

Our study's primary goal is to measure the total opioid consumption on postoperative days (POD)# 0 and 1. Our secondary goals are to measure the pain scores on a visual analog scale (VAS) on POD# 0 and 1, measure the time it takes for participants to move their feet to command when surgery is done, and measure the time it takes for participants to be extubated when surgery is done. By comparing these measurements, the investigators hope to find out if there is any significant difference between the two TIVAs in terms of postop opioid requirements, pain scores, and time to wake up from anesthesia.

The investigators hope that our study gives us more knowledge on how to better treat postoperative pain in children who have spine surgery to correct their

Patients with Adolescent Idiopathic Scoliosis (AIS) may need surgery to correct their scoliosis. General anesthesia is required for this surgery, and a multimodal analgesic regimen using combinations of opioid and non-opioid medications is the standard of care. Total intravenous anesthesia (TIVA) is the usual anesthetic technique of choice.

The purpose of this study is to compare two combinations of TIVA medications in children AIS having posterior spinal fusion surgery.

The most common TIVA for this surgery at our institution is Propofol + Remifentanil. Remifentanil is a popular choice because of its rapid onset, extremely short context-sensitive half-life, potency, and its rapid recovery from drug effect. However, an important concern with intraoperative remifentanil infusion is the possible development of acute opioid-induced hyperalgesia (OIH). In adults, OIH is a well-documented feature linked to intraoperative remifentanil administration, manifesting as increased postoperative analgesic requirement and paradoxical increase in sensitivity to painful stimuli. In pediatric patients, the phenomenon is not as well characterized.

An alternative TIVA that is very commonly used for adult spine surgery is propofol + dexmedetomidine (DEX). DEX is a highly selective alpha2-adrenergic receptor agonist with sedative, analgesic, and sympatholytic properties.

Despite the lack of FDA approval for pediatric use, DEX is widely used off-label in pediatric patients in the US and worldwide and has previously been shown to be safe and efficacious for various clinical indications including procedural sedation, craniotomy-awake-surgery, cardiac surgery, and posterior spinal fusion for scoliosis. DEX is currently used safely in pediatric and adult spine patients in our institution. The most common adverse effect is intraoperative bradycardia.

Participants will be randomized to receive one of the two TIVAs to see if one or the other results in lower opioid consumption, and lower Visual Analog Scale (VAS) pain scores in the post-operative period (POD# 0 and 1). The investigators hypothesize that the use of DEX will avoid OIH and this will lead to less opioid consumption in the postoperative period, and superior postoperative pain control. The investigators also hope to show that the use of DEX will not significantly prolong time to moving feet to command and extubation at conclusion of surgery.

Eligibility Criteria:
Inclusion Criteria:

* Age 12-18 years old
* American Society of Anesthesiology Physical Status Classification (ASA Class) 1 and 2
* Have diagnosis of Adolescent Idiopathic Scoliosis
* Undergoing Posterior Spinal Fusion with instrumentation for scoliosis correction
* Matched on age, sex, and the number of vertebral levels fused

Exclusion Criteria:

* Neuromuscular scoliosis
* Allergy to any of the multi-modal analgesia regimen drugs
* Use of serotonergic drugs, monoamine oxidase inhibitors (MAOI), mixed agonist/antagonist opioid analgesics