To compare the analgesic efficacy of dexmedetomidine and magnesium sulphate as adjuvants to levobupivacaine in erector spinae plane block in modified radical mastectomy surgery for acute and chronic pain management.

3 groups.

Group (C) / (I):20 patient (control group) :

Patients will receive 20 ml 0.25% levobupivacaine into the interfascial plane below erector spinae muscle at level of T5.

Group (D)/ (II) :20 patient (Dexmetonidine group) :

Patient will receive 20ml 0.25% levobupivacaineas above + 1μ/kg dexmedetomidine.

Group (M) / (III) : 20 patient (magnesium slphate group) :

Patient will receive 20ml 0.25% levobupivacaineas above + 0.7 mg/kg MgSo4 . The patient, the anesthesiologist who administered the drugs, and the data collector will be blinded to the study drugs.

Inclusion Criteria:

• female patient
• American society of anesthesiologists (ASA) I and II physical status
• age from 25 to 70 years old
• scheduled for either left or right modified radical mastectomy (MRM).

Exclusion Criteria:

• infection of the skin at or near site of needle puncture
• coagulopathy
• drug hypersensitivity or allergy to the studied drugs
• central or peripheral neuropathy
• significant organ dysfunction cardiac dysrrhythmias
• obesity (BMI>35kg/m2)
• recently use analgesic drugs