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.

Inclusion Criteria:

1. Patients 40-80 years old, males and females, of any race and any ethnic group.
2. Patients are scheduled for elective primary posterior cervical spine fusion surgery (CSFS) to be performed by one of the spine surgeons in the study.
3. Ability to speak and read English
4. Patients with American Society of Anesthesiology (ASA) physical status score I- IV

Exclusion Criteria:

1. Emergency posterior CSFS.
2. Revision surgery or history of previous cervical spine surgery
3. History of allergy to local anesthetics or steroids.
4. Patients who are coagulopathic at the time of surgery
5. Patients with contraindications to MCP blocks, including but not limited to anatomical abnormality or previous surgical intervention that limits or prevents receiving the blocks
6. Infection at the site of the block.
7. Weight < 40 kg to avoid local anesthetic toxicity.
8. Patients on chronic or continuous opioid use of > 50 MME (morphine milli-equivalent) per day for at least 30 days within 90 days prior to surgery.
9. Patients with a history of chronic inflammatory conditions such as multiple sclerosis
10. Refusal to participate or lack of providing the study consent

This is a double-blinded study, patients, research coordinators who collect data, spine surgeons, and other health care providers will all be blinded to the study group assignments to minimize bias and maximize the validity of study results. The block-performing anesthesiologists/investigators, the block nurse, and the senior scientist will not be blinded to the study group assignments.

Patients will not be unblinded after they complete the study or during the study unless a participant experiences a serious adverse event that is unexpected and related to the study intervention (MCP or sham block) and the course of treatment needs to be adjusted. Unblinding in this situation will be the decision of the principal investigator (PI). The PI will contact the Senior Scientist to get the patient's group assignment, and the PI will then unblind the patient (i.e., tell the patient about the assigned group), and take any additional necessary course of treatment.