The goal of this randomized, double-blinded, clinical trial is to assess the benefit of administering a Multifidus Cervicis Plane (MCP) block compared to a sham block as a method of postoperative pain control in patients undergoing posterior cervical spine fusion surgery. The main question it aims to answer is if the MCP block group will have reduced maximum pain scores during the first 24 postoperative hours compared to the sham block group. Participants will receive preoperative bilateral MCP blocks on the back of their neck using the standard of care local anesthetic solution that consists of 30 mLs 0.25% Bupivacaine + 0.5 mL (5 mg) preservative-free Dexamethasone + 0.1 mL Epinephrine (MCP block group). Researchers will compare the MCP block to the preoperative sham block which consists of injecting 3 mL of normal saline into the same area (Sham block group) to compare the postoperative pain scores between the groups as a main objective. The secondary objectives are: * Postoperative opioid consumption during hospitalization and at 2 weeks after discharge. * The amount and type of non-opioid analgesics used during hospitalization. * The occurrence of postoperative nausea and vomiting (PONV) and the use of antiemetics. * Hospital and Post Anesthesia Care Unit length of stay (LOS). * Monitor the safety of the study interventions during hospitalization and readmissions within 30 days of discharge. * Patient satisfaction with pain management and overall satisfaction with the surgery experience.