Postoperative Pain Management after Spinal Fusion Surgery: An Analysis of the Efficacy of Continuous Infusion of Local Anesthetics

摘要

Spinal fusion surgery is a major surgery that results in severe postoperative pain, therefore pain reduction is a primary concern. New strategies for pain management are currently under investigation and include multimodal treatment. A 3-year retrospective analysis of patients with idiopathic scoliosis undergoing spinal fusion surgery was performed at our hospital, assessing patient pain scores, opioid use, and recovery. We evaluated the effect of adding continuous infusion of local anesthetics (CILA) to a postoperative pain management protocol that includes intraoperative intrathecal morphine, as well as postoperative patient-controlled analgesia and oral opioid/acetaminophen combination. The study compared 25 patients treated according to the standard protocol, with 62 patients treated with CILA in addition to the pain management protocol. Patients in the CILA group used nearly 0.5 mg/kg less opioid analgesics during the first 24 hours after surgery. Keywords: spinal fusion, idiopathic scoliosis, continuous infusion of local anesthetics, post-operative pain management Adolescent idiopathic scoliosis (IS) is a condition of unclear etiology that occurs in 1 to 3% of otherwise healthy children and adolescents and when severe can result in respiratory and cardiovascular deterioration. 1 2 3 When the curvature exceeds a certain severity, spinal fusion surgery is indicated, with a goal of correcting the existing curve and preventing further progression while preserving pulmonary function. 4 5 However, spinal fusion surgery can result in severe postoperative pain, 5 6 7 and when it is the chosen treatment, pain management is a primary concern. The standard of care for pain management for spine surgery in children consists of continuous infusion of intravenous (IV) morphine supplemented with patient-controlled analgesia (PCA). However, to achieve satisfactory pain control with this method, high doses of opioids must be administered. Unfortunately, use of opioids is associated with serious adverse effects, including nausea, vomiting, pruritus, sedation, and respiratory depression, which often delay patient recovery. 8 Moreover, patient recovery times are also delayed by high postoperative pain levels, potentially leading to poorer patient outcomes. 9 To reduce postoperative pain levels, decrease recovery time, and increase patient satisfaction, a balance between analgesia and adverse effects of the medication should be achieved. Recent studies of pediatric patients have evaluated the efficacy of different types and combinations of anesthetics and routes of delivery in an attempt to achieve adequate pain control while limiting side effects caused by opioid use. 10 These investigations include those comparing continuous epidural analgesia of a combination of opioids and local anesthetics to PCA or IV morphine alone. 11 12 13 14 15 16 17 Other studies involve comparisons of different epidural anesthetics 18 19 as well as optimization of dose of intrathecal morphine, 20 21 22 23 with variable results. Still another investigation examined the efficacy of the combination of intrathecal morphine and continuous infusion of IV morphine without PCA, under strict protocol guidelines, as a postoperative pain management strategy for spinal fusion surgery. 24 These studies suggest that use of combinations of different types of analgesia along with different routes of administration maximizes pain relief while minimizing the adverse effects. Some studies show that supplementing the pain management regimen with continuous infusion of local anesthetics (CILA) into the surgical site with an elastomeric pain pump significantly improves pain control, particularly for orthopedic surgeries 25 26 and adult spinal fusion surgeries. 27 It has been shown that CILA is effective in reducing postoperative pain in children, 28 29 and to our knowledge its use for pediatric spinal fusion surgery has been described in one other publication, with promising results. 30 Given the evidence outlined above, there is no conclusive answer as to the best pain management protocol for pediatric spinal fusion surgery patients. However, there is evidence that a multimodal approach to pain management is most effective, utilizing different therapeutic classes of analgesics administered through distinct routes of administration. 10 The purpose of this investigation is to determine whether the addition of CILA to our pain management regimen for spinal fusion surgery reduced opioid use or pain levels during the first 3 postoperative days.