The effect of intraoperative intrathecal opioid administration on the length of stay and postoperative pain control for patients undergoing lumbar interbody fusion

Endogenous opiates and behavior: 2022

This paper is the forty-fifth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2022 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Does the combination of intrathecal fentanyl and morphine improve clinical outcomes in patients undergoing lumbar fusions?

Intrathecal morphine (ITM) has been widely effective in improving postoperative outcomes in patients undergoing a multitude of surgeries, including lumbar spine fusion. A major limitation of ITM administration is the increase in the incidence of respiratory depression in a dose-dependent manner. One way to bypass this is to use a more potent opioid with a shorter half-life, such as fentanyl. This is a retrospective analysis of patients who underwent one- or two-level transforaminal lumbar interbody fusions. The patients received one of two interventions: 0.2mg intrathecal duramorph/morphine (ITM group; n=70), 0.2mg duramorph + 50 mcg fentanyl (ITM + fentanyl group; n=68) and the control group (n=102). Primary outcomes included postoperative pain (Visual Analog Scale) and opioid intake (MED - morphine equivalent dosage, mg) for postoperative days (POD) 1- 4. Secondary outcomes included opioid-related side effects. One-way analyses of variance and follow-up post-hoc Tukey's honest significant difference statistical tests were used to measure treatment effects. Significantly lower POD1 pain scores for both the ITM and ITM + fentanyl groups vs. control were detected, with no difference between the ITM vs. ITM + fentanyl groups. Similar results were found for POD1 MED intake. A multivariate regression analysis controlling for confounding variables did not attenuate the differences seen in POD1 pain scores while revealing that only the ITM + fentanyl predicted a decrease in POD1 MED intake. No differences were seen for postoperative opioid-related side effects. Our study provides support for supplementing a low dose of both intrathecal morphine and fentanyl to improve postoperative outcomes.

Frequency of typical complications of morphine during its intrathecal and epidural introduction in knee arthroplasty

The objective was to compare the efficacy and safety of morphine in neuraxial blocks during knee arthroplasty.

Materials and methods. A retrospective analysis of 60 medical histories of patients who underwent total knee arthroplasty for the period from 2017 to 2019 was performed. All patients were operated under  general anesthesia  with mechanical  ventilation in combination with epidural  or spinal analgesia with opiates. Patients of the 1st  group (n=20) after catheterization of the epidural space at the level of L1–2 were injected with a morphine solution 1% – 0.3 ml epidurally. Patients of the 2nd  group (n=20) were injected with a morphine solution 1% – 0.01 ml intrathecally at the level of L3–4. Patients of the 3rd group (n=20) underwent standard combined anesthesia:  general anesthesia  with mechanical  ventilation and epidural  analgesia at the level of L1–2  with a solution of 0.2% ropivacaine  in the form of an infusion of 6 ml/hour. All patients received infusion of 0.2% solution of ropivacaine  epidurally  6 ml/hour at the level of L1–2  in the postoperative period.

The incidence of nausea, vomiting, pruritus, headache and the level of postoperative pain syndrome were assessed on a numerical rating scale 6 hours after the end of the surgery.

Results. The level of pain syndrome in patients who received intrathecal and epidural analgesia with morphine was equally low, while in patients who received epidural  analgesia with ropivacaine,  the level of pain syndrome was statistically significantly  higher, which required  the additional prescription of non-steroidal anti-inflammatory drugs and/or narcotic  analgesics parenterally. The frequency  of nausea, vomiting,  pruritus and headaches was maximum in the 2nd  group, significantly lower in the 1st, while in the 3rd, pruritus did not occur.

Conclusion. The use of morphine in neuraxial block in knee arthroplasty has a positive effect on the quality of anesthesia and postoperative pain relief.