Spinal surgeries are frequently conducted to stabilize the vertebrae and discs of the spine. These surgeries typically require substantial manipulation of subcutaneous tissues, bones, and ligaments . Postoperative pain relates to mechanical irritation, compression, and postoperative inflammation. The uncontrolled pain could promote the development of chronic persistent pain and worsen independence, mood, and quality of life. Effective pain management facilitates early mobilisation and accelerates hospital discharge. this study aim to investigate the effectiveness of a mixture of dexmedetomidine and bupivacaine in classical thoracolumbar interfascial plane block compare to modified thoracolumbar interfascial plane block on postoperative pain in patients undergoing lumbar disc surgeries.

Postoperative pain control after spinal surgeries has been a topic of interest for researchers in the past decade. Indeed, poor pain control can not only impact patient satisfaction but also delay rehabilitation and increase healthcare costs.

The thoracolumbar interfascial plane (TLIP) block was defined by Hand et al. for reducing pain following spinal surgery. In this block, the anesthetic drug is administered between the multifidus and longissimus muscles to target the dorsal ramus of the thoracolumbar nerves. The TLIP block was later modified by Ahiskalioglu et al., with the involvement of the administration of a local anesthetic between the longissimus and iliocostalis, which was observed to demonstrate a dermatomal dispersion similar to that by the TLIP block.

Dexmedetomidine is highly specific and highly selective a2-adrenoceptive agonist and it's action is selective to the CNS without the unwanted effect on the CVS that would result from a activation . It has been found that, in many experimental and clinical regional block practices, the addition of dexmedetomidine to the local anesthetic reduces tissue and nerve damage, increases duration of sensory and motor block, and reduces postoperative pain.

Inclusion Criteria:

• • Age >18 years old

  • Both sex
  • Patients who were in risk-scoring groups I-II of the American Society of Anesthesiologists (ASA)

Exclusion Criteria:

• • Patient refusal.

  • coagulation disorders that affect the blood's clotting activities e.g.: Hemophilia.
  • skin lesions or infection at site of proposed needle.
  • known allergy to local anesthetics or dexmedetomidine.
  • patients suffering from mental disease as cannot Assess the Visual Analogue Scale (VAS) that measures pain intensity as, mental retardation & psychosis

An independent anesthesiologist randomly using computer-generated random numbers divided the patients into 2 groups :(Group 1 and Group 2). Each group will include 15 patients. We discreetly placed the randomization results in envelopes until the end of the study. The researchers who were responsible for postoperative follow-up and data processing were blinded to the group allocation during the whole study period. All patients were also blinded to the group allocation