A Study of Intrathecal Hydromorphone for Pediatric Idiopathic Scoliosis Repair

Identification of the Optimal Analgesic Dose of Intrathecal Hydromorphone for Pediatric Patients Undergoing Posterior Spine Surgery for Idiopathic Scoliosis

The purpose of this study is to identify a dose of intrathecal hydromorphone (opioid pain medicine) that optimizes pain control but minimizes side effects historically seen with this class of pain medications.

This study is a sequential coin based up-down dose allocation method with the goal of identifying the ED90 for intrathecal hydromorphone (ITH) in idiopathic adolescent scoliosis repair via the posterior approach. A starting dose of 3.5 mcg/kg of hydromorphone was determined by current practice at the institution as well as upon review of available literature of previously used ITM doses in pediatric spine patients. Subsequent participants will receive higher (step "up") or lower (step "down") from this starting dose. Steps "down" from the starting dose will be smaller than steps "up" to ensure maintenance of adequate analgesia and to allow more accurate estimate of the optimal dose should it decrease beyond our starting dose. Steps "up" from the starting dose were chosen based on commonly used weight-based doses in our current practice. A maximum dose of 400 mcg, despite patient weight, was determined based on expert consensus and review preparatory to research query. The anesthesiologist covering the case (high lumbar or thoracic corrections) or the surgeon (low lumbar corrections) will administer the medication at the low lumbar level. ITH dose adjustments for subsequent study patients will be based on the efficacy of the dose used with the prior patient. Efficacious ITH administration will be defined as all NRS scores ≤5 within the first 18 hours after administration (binary outcome). If the NRS score was >5 within 18 hours or if the patient required supplemental opioid administration for pain control (suggestive of insufficient analgesia), the dose will be increased for the next enrolled study patient. If the pain score remains ≤5 within 18 hours of opioid administration, the next patient will receive the next lower dose or the same dose as the previous patient. Patients excluded after randomization will be removed from the study.

Subjects undergoing posterior spinal surgery will receive 2.5 mcg/kg hydromorphone in the intrathecal space at the low lumbar level

Subjects undergoing posterior spinal surgery will receive 2.75 mcg/kg hydromorphone in the intrathecal space at the low lumbar level

Subjects undergoing posterior spinal surgery will receive 3 mcg/kg hydromorphone in the intrathecal space at the low lumbar level

Subjects undergoing posterior spinal surgery will receive 3.25 mcg/kg hydromorphone in the intrathecal space at the low lumbar level

Subjects undergoing posterior spinal surgery will receive 3.5 mcg/kg hydromorphone in the intrathecal space at the low lumbar level

Subjects undergoing posterior spinal surgery will receive 4 mcg/kg hydromorphone in the intrathecal space at the low lumbar level

Subjects undergoing posterior spinal surgery will receive 4.5 mcg/kg hydromorphone in the intrathecal space at the low lumbar level

Subjects undergoing posterior spinal surgery will receive 5 mcg/kg hydromorphone in the intrathecal space at the low lumbar level

Reported by the patient using an 11-point numeric visual analogue scale (NRS) with 0=no pain and 10=worst pain ever

Number of subjects needing dual anti-pruritic agents (Nubain or naloxone (beyond the protocol infusion rate of 0.25 mcg/kg/min))

Highest pain score reported during the first 24 hours after intrathecal opioid administration. Reported by the patient using an 11-point numeric visual analogue scale (NRS) with 0=no pain and 10=worst pain ever.

Inclusion Criteria: - Undergoing spinal surgery with a posterior approach for idiopathic scoliosis. Exclusion criteria: Patients with pre-surgical elevated pain scores (≥ 3/10 on Numeric Rating Scale (NRS)), history of chronic pain, or pre-surgical opioid use will not be included. Patients with contraindications to spinal anesthesia (anatomical abnormality or elevated bleeding or infection risks) will not be included. Patients for whom the protocol is violated (inability to perform postoperative data collection), or the study/procedure was aborted will not be included in analysis.