Effect of Ultrasound Guided Erector Spinae Plane Block Versus Perioperative Intravenous Lidocaine Infusion on Proinflammatory Cytokines in Breast Cancer Surgeries

Breast surgery is a widely performed procedure worldwide, with a significant number of patients experiencing moderate to severe acute pain (30 50%) and developing chronic post-surgical pain (CPSP) (25-68%). CPSP, characterized by persistent or worsening pain in the breast region lasting for at least 3 months after surgery, can have detrimental effects on emotional well being, functional abilities, quality of life, and impose substantial financial burdens on healthcare systems. The pathophysiology of CPSP involves mechanisms such as traumatic nerve injury, neuroinflammation, and central neuronal sensitization. Stress response to cancer surgeries is usually associated with a group of interactions between the endocrinal, the sympathetic, and the immunological systems resulting in imbalance between pro- and anti-inflammatory cytokines in addition to activating an inflammatory cascade. Exaggerated production of inflammatory mediators (e.g. interleukins [ILs] and tumor necrosis factor alpha [TNFα]), and immune cell dysfunction (e.g. CD4 T) can lead to haemodynamic instability or metabolic derangements besides increasing the susceptibility of postoperative infection, resulting in delaying wound healing, multiple organ dysfunction, and postoperative morbidity. Tissue and peripheral nerve injury leads to a local inflammatory reaction accompanied by increased levels of pro-inflammatory cytokines, including interleukin IL-1 and IL-6, which induce peripheral and central nervous system sensitization leading to hyperalgesia. IL-1 induces long-lasting synthesis and release of substance P from peripheral nerve terminals of primary afferent neurons, which may contribute to neurogenic inflammation. The conventional approach to managing postoperative pain relies heavily on opioids, which carries the risk of adverse effects including respiratory depression, addiction, and even mortality. To address these challenges, multimodal analgesic strategies have been proposed to alleviate both acute and chronic postoperative pain following breast surgery. Lidocaine, being used originally as an antiarrhythmic agent, has been found to possess antinociceptive, anti-inflammatory and anti-hyperalgesia properties, making it a potentially useful drug for relieving postoperative pain.

The systemic administration of lidocaine has shown efficacy in relieving neuropathic pain. Previous meta-analyses have demonstrated the effectiveness of intravenous lidocaine in reducing postoperative pain and opioid consumption in patients undergoing spine and abdomen surgery. However, the efficacy of intravenous lidocaine specifically for breast surgery has not been extensively evaluated due to limitations such as small sample sizes and conflicting findings from individual studies. To supply complete analgesia postoperatively for patients undergoing breast surgeries, it is essential to ideally block the dermatomes of the spinal nerves from C5 to T6. Many techniques have been used widely to control pain after breast surgeries as para vertebral block, epidural block, and intercostal block. Although no optimal method has been defined yet, each one of these techniques has some flaws. Epidural block can lead to unwanted block to the opposite side, epidural abscess, epidural haematoma and accidental dural puncture. Paravertebral block can result in an ideal analgesia, but it has drawback that it can be complicated by pneumothorax and it may be difficult to perform. The intercostal nerve block is simple to apply, but it requires to be performed in several segments.