Purpose: Postoperative pain is common following posterior spinal fusion (PSF) and segmental spinal instrumentation (SSI) for idiopathic scoliosis (IS). It is often treated with intravenous morphine patient controlled analgesia (PCA), but no studies have examined continuous morphine infusion. The purpose of this study was to identify the safety and efficacy of continuous morphine infusion without PCA for post-operative pain management in these patients.

Method: We retrospectively reviewed 338 consecutive patients from 1992 to 2006 who received continuous morphine infusion. Following induction of general anesthesia and prior to surgical incision, patients received intrathecal morphine for preemptive analgesia. Anesthesia was maintained with 50% nitrous oxide and up to 0.6% isoflurane, with minimal or no intravenous opioids. Following surgery, pre-ordered morphine infusion (0.01 mg/kg/hr) began when patients first reported pain. The infusion rate was titrated using a strict protocol based on frequent assessment of vital signs, Wong-Baker visual analog pain scores (VAS), and clinical status. The infusion continued until patients were able to take oral analgesics at postoperative day 2–3. Factors analyzed included patient demographics, intrathecal morphine dosage, intraoperative intravenous opioid dosage, pain scores through the third postoperative day, interval to start of morphine infusion, total morphine requirement in the first 48 postoperative hours, and postoperative complications.

Results: Mean intrathecal morphine dose was 15.45 mcg/kg and mean interval to start of morphine infusion was 15:45 hours. Mean VAS pain scores were 3.05, 4.48, 4.48, and 4.60 at 12 hours, 1, 2, and 3 days postoperatively. The total mean dosage of morphine in the first 48 hours postoperatively was 0.03 mg/kg/hr. Nausea/vomiting, pruritis, respiratory depression, and PICU admissions related to the morphine drip occurred in 13.3%, 4.1%, 0%, and 0% of the patients during the same time period.

Conclusion: A low frequency of adverse events and a mean postoperative pain score of 5 or less demonstrates that continuous postoperative morphine infusion is a safe and effective method of pain management in children following PSF and SSI for IS. Continuous morphine infusion without PCA is a safe, alternative method of pain control for postoperative patients with IS.

Purpose: Do children from different gender or racial groups receive different analgesic doses for the same acute pain condition? We previously reported on intra-thecal morphine for preemptive analgesia in children undergoing posterior spinal fusion (PSF) and segmental spinal instrumentation (SSI) for idiopathic scoliosis (IS). We determined the optimal dose range to maximize analgesia while minimizing adverse effects. The purpose is to ensure this adopted protocol is equally effective across gender and racial groups.

Method: We studied 407 intrathecal morphine patients. Those given a moderate dose of 9–19 mcg/kg (n=293) had the most effective and safe postoperative pain relief. This group consisted of 246 female and 47 male patients. There were 224 Caucasian (CA) and 63 African-American (AA) patients. Other ethnicities were excluded. Factors analyzed included postoperative Wong-Baker visual analog pain scores (VAS), time to first opioid rescue dose, total morphine dose over the first 48 hours, and postoperative complications.

Results: For female and male gender, mean VAS pain scores in post-anesthesia care unit (PACU) were 0.48 and 0.56, mean times to first opioid rescue dose were 999.1 and 1003.3 minutes, and total morphine over the first 48 hours were 1.5mg/kg in both groups, respectively. Respiratory depression and PICU admission occurred in 2 (4.2.%) and 4 (1.6%) patients, respectively. For CA and AA patients, mean VAS pain scores in PACU were 0.48 and 0.46, mean times to first opioid rescue dose were 991.7 and 1031.9 minutes, and total morphine over the first 48 hours were 1.5mg/kg and 1.3mg/kg, respectively. Respiratory depression occurred in 5 (2.2.%) and 2 (3.2%) patients and PICU admission occurred in 4 (1.8.%) and 4 (6.3%) patients, respectively. StudentÂ’s t-test and Fisher exact test demonstrated no significant differences between genders for all variables, and no significant differences between races except less total morphine for AA patients over the first 48 hours (p=0.0024).

Conclusion: An optimal intrathecal morphine dose range of 9–19 mcg/kg provides effective and safe postoperative pain relief in children undergoing PSF and SSI for IS, regardless of gender or race. Intrathecal morphine can be given with the assurance that it does not discriminate against gender or provide less optimal analgesia to AA patients.