BACKGROUND CONTEXT Adolescent idiopathic scoliosis is the most common form of scoliosis and occurs most commonly in girls. When surgical intervention is required, the corrective operation is associated with significant postoperative pain which is primarily treated with morphine or morphine equivalents such as hydromorphone. The ideal regimen for postoperative pain management for pediatric spinal fusion has not been determined. PURPOSE The present study is a prospective randomized double-blinded control trial comparing the use of a preincision ketamine bolus, slow intraoperative infusion, and continued infusion postoperatively for 48 hours, to the placebo group's standard morphine regimen for corrective spinal fusions for idiopathic scoliosis in pediatric patients. The primary outcome for this study is patient satisfaction, and secondary outcomes include morphine equivalent opioid consumption, incidence of side effects, pain scores, and duration of hospital stay. We aimed to show that the addition of ketamine to standard pain control regimen will reduce pain scores and overall morphine equivalent consumption on a mg/kg basis, and thereby improve patient satisfaction. STUDY DESIGN/SETTING Prospective randomized double-blinded control trial performed at a regional academic medical center in New York. PATIENT SAMPLE A total of 50 patients allocated between placebo group and experimental (ketamine) group. ASA I-III. Mean age of 14. All undergoing posterior spinal fusion surgery for correction of adolescent idiopathic scoliosis refractory to non-surgical interventions. OUTCOME MEASURES Patient satisfaction, morphine equivalent consumption (mg/kg), incidence of side effects, pain scores, length of stay. METHODS A racemic ketamine bolus of 0.5 mg/kg (experimental - ketamine) or saline bolus (placebo) was given and then the ketamine or saline infusion of 0.2 mg/kg/hr was initiated prior to incision and continued intraoperatively. Postoperative pain management included continuation of the study drug for 48 hours in combination with standard morphine patient-controlled analgesia (PCA) and acetaminophen 15 mg/kg (up to 1 g) IV. Hourly pain scores were collected by bedside nurses, and the highest pain score for each 4-hour time period until postoperative day 2 (48 hours) was recorded. Patient and parental satisfaction scores were collected at postoperative hours 1, 24, and 48. Satisfaction scores ranged from 0 – 4, with 4 being the most satisfied. RESULTS Of the 49 total patients analyzed: 25 received the placebo, 24 received ketamine. Demographic and surgical variables were the same across groups except for age and gender. The placebo group had a mean intraoperative morphine equivalent consumption of 20.5 mg, 95% CI (17.2 – 23.8), and the experimental group had a mean of 17.4 mg, 95% CI (14.3 – 20.4), yielding no significant difference (p = 0.16). The placebo group had a median PACU morphine equivalent consumption of 6.67 mg, IQR [0.25 – 8.67], and the experimental group had a median of 2.34 mg, IQR [0 – 7.17], yielding no significant difference (p = 0.31). Postoperative morphine equivalent consumption (mg/kg) was significantly lower in the experimental group, median of 0.443 mg/kg, IQR [0.299 – 0.789], compared to the placebo group, median of 0.703 mg/kg, IQR [0.43 – 1.28] (p = 0.042). This yields a 37% reduction in consumption. Initial comparison of pain scores was insignificant with a placebo mean VAS score of 3.9, 95% CI (3.14 – 4.66), and an experimental mean VAS score of 3.17, 95% CI (2.45 – 3.89) (p = 0.155). Multiple linear regression analysis of pain scores yielded a significant reduction in pain within the experimental group when accounting for differences in age and gender (decrease of 1.5/10 on the VAS) (p CONCLUSIONS The use of ketamine alongside the standard morphine equivalent pain control regimen reduces the amount of IV PCA opioids consumed in the 48-hour postoperative time period. The significant reduction in the incidence of nausea and vomiting provides an additional benefit to this alternative analgesic therapy. This effect may be a secondary result of the reduction in total opioid consumption on a mg/kg basis, therefore reducing the known effects of opioids to induce nausea and vomiting. The application of ketamine as an analgesic in conjunction with the current standard of morphine-based therapy may serve as a superior pain control regimen for spinal surgeries in young populations. This regimen enhancement may be generalizable to other surgery subtypes within similar populations. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.
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Open Access
May 18, 2021
Sarah Tallent + 4
