Comparison of Dexmedetomidine Versus Dexamethasone as Adjuncts to Levobupivacaine in Ultrasound Guided Erector Spinae Plane Block for Patients Undergoing Modified Radical Mastectomy, Randomized Double-Blinded Comparative Study.

Breast cancer is the most common malignancy among females. Modified Radical Mastectomy (MRM) is one of the main surgical treatments of breast cancer .The most common modality for anesthesia is general anesthesia with or without regional blocks . Nearly 40-60% of patients undergoing breast surgery experience severe acute postoperative pain, with severe pain persisting for 6-12 months in almost 10-30% of patients (Post Mastectomy Pain Syndrome; PMPS) . This pain can be severe enough to cause long-term disabilities and interfere with sleep and performance of daily activities.

Postoperative pain is usually managed by opioids, yet it is usually associated with side effects including; prolonged sedation, increase in the incidence of recurrence, respiratory depression , nausea , vomiting and ileus. In an attempt to reduce these side effects, thoracic epidural analgesia and paravertebral block became the gold standard regional techniques for breast surgery. However, both techniques may be associated with serious complications such as pneumothorax, spinal cord injury, incompatibility with pre-existing anticoagulation or antiplatelet therapy and hemodynamic instability. Multiple different regional techniques have been developed in the last decade for postoperative pain management of MRM including including erector spinae plane block (ESPB) aiming to be effective and associated with less complications when compared to the gold standard techniques .

ESPB is a simple and safe paraspinal fascial plane block that involves injection of local anesthetic deep in the erector spinae muscle and superficial to the tips of the thoracic transverse processes hoping to block both ventral and dorsal rami of spinal nerves in the paravertebral area. However, regional blocks after a single dose of local anesthetic are of limited duration and efficacy. Hence, the co-administration of adjuvants with local anesthetics may be helpful for prolongation and potentiation of the analgesic effect. Dexmedetomidine is a potent α2agonist of which α2/α1 selectivity is 8 times greater than clonidine and is now emerging as an adjunct to regional and general anesthesia. It can prolong the duration of the nerve block when used with a local anesthetic .Dexamethasone is considered as an adjuvant as it act by reducing the release of inflammatory mediators and by inhibiting discharge of C-fibers. There is a limited number of studies covering the effect of dexmedetomidine versus dexamethasone when added to ESPB, yet they are still lacking in breast surgeries. Our study aims at studying the effect of adding dexmedetomidine compared to dexamethasone as adjuncts to ESPB in modified radical mastectomy.

Objectives:

To identify the intraoperative and postoperative opioid consumption, as well as duration of analgesia and study the effect on hemodynamics.