This randomized prospective double blinded study will aim to evaluate the postoperative analgesic effect of ultrasound guided Erector Spinae plane block and local wound infiltration (drain block) for patients scheduled for modified radical mastectomy surgery.

Breast cancer is the most commonly diagnosed cancer worldwide and it represents 1 in 4 cancers diagnosed among women globally. Modified Radical Mastectomy (MRM) is a commonly performed surgery for breast cancer and is associated with moderate-to-severe postoperative pain. Poor postoperative pain management can lead to increased chances of the development of chronic pain. Therefore, adequate postoperative pain management after breast cancer surgery is essential. Regional block for pain management has many advantages in such patients including provision of adequate analgesia, reduced need for opioids, decreased postoperative nausea & vomiting and postoperative pulmonary complications. It also facilitates early ambulation. Thoracic Epidural (TE), paravertebral block (PVB), pectoral nerve I & pectoral nerve II blocks, serratus anterior plane block and erector spinae plan block have been used with good results. In particular, the erector spinae has proven to reduce pain severity and opioid consumption in this group of patients. Further, in meta-analysis, the ESP block was shown to effectively alleviate postoperative pain severity and reduce opioid consumption. In ESP block, local anesthetic is deposited deep to the erector spinae muscle which results in blocking of the ventral and dorsal rami of multiple spinal nerves. The LA diffuses into the paravertebral space and cephalo-caudally and blocks the pain by action on dorsal rami, ventral rami, and lateral cutaneous branches of intercostal nerves. Also, in many situations, a superior postoperative analgesia yet avoiding the detrimental effects of opioids, can be extracted from a simple technique of wound instillation of local anesthetics through surgical drain which provide a satisfactory long opioid free postoperative analgesic period.

Inclusion Criteria:

• American Society of Anesthesiology (ASA) physical status I-II
• scheduled for unilateral Modified radical mastectomy

Exclusion Criteria:

• Patient refusal.
• Patient with neurological deficit.
• Patient with bleeding disorders.
• Uncooperative patient.
• Infection at the block injection site.
• Patients with history of allergy to local anesthetics.
• Advanced hepatic, cardiac or renal failure.
• Chronic opioid consumption.
• Body mass index (BMI)≥ 30 kg m-2
• Chronic use of gabapentin or pregabalin