Posterior cervical spine surgery often requires a large posterior midline incision, resulting in poorly controlled postoperative pain, which arises from iatrogenic mechanical damage, intraoperative retraction, and resection to structures such as bone, ligaments, muscles, intervertebral discs, and zygapophysial joints.

Ultrasound-guided Inter-semispinal plane (ISP) block, was proposed as a novel technique for analgesia in posterior cervical spine surgeries. The ISP block involves an injection of local anesthetic into the fascial plane between the semispinalis cervicis and semispinal capitis muscles and results in blocking the dorsal rami of the cervical spinal nerves. ISP block can provide effective analgesia in posterior cervical spine surgery

Inclusion Criteria:

• Patients' acceptance.
• ASA I , II andIII .
• Age between 18 years up to 70 years in both sexes.
• Patients with a BMI (body mass index) ranging from 18.5 to 30 kg/m2.
• Patients who scheduled for elective posterior cervical spine surgeries

Exclusion Criteria:

• Uncooperative patients
• Coagulopathy.
• Local tissue infection.
• Allergy to local anesthesia.

Data will be available on permission

After one year from publishing to a journal

Randomization assignments will be kept in sealed envelopes until all preprocedural measurements will be completed, and then they are opened by the research anesthesiologist immediately prior to the nerve block.