Ultrasound Guided Serratus Posterior Superior Intercostal Plane Block Versus Pectoral Nerve (PECS II) Block For Pain Control In Breast Surgeries: A Randomized Comparative Trial

All patients will be seen in the anesthesia clinic, optimization of general condition and all required investigations will be done before surgery. Patients will be premedicated with 1.5 mg midazolam and 4 mg granisetron. Standard basic monitoring will be applied to all patients then after adequate preoxygenation, induction of general anesthesia will be done through wide bore cannula using 1 mic/kg fentanyl, 1-2 mg/kg titration of propofol, 0.5mg/kg atracurium. Patients were mechanically ventilated using volume-controlled ventilation (VCV) with adjustment of end tidal carbon dioxide (ETCO2) to be 32-35 mmHg, 50% inspired oxygen in air and sevoflurane concentration to be 1MAC. The patients will receive either block before skin incision that will be done 20 minutes after the block. 0.5 mic/kg fentanyl will be injected when heart rate or blood pressure increases more than 20% of baseline. By the end of the surgery, 1gm paracetamol will be administered with fully reversal of muscle relaxants at the end of the surgery.

SPSIP group After induction of anesthesia, patients will be placed in lateral decubitus position, the affected arm will be adducted and medially rotated. Under complete aseptic technique, a high frequency linear probe will be placed adjacent to upper medial part of scapula to visualize the second and third ribs. The structures from superficial to deep are skin, subcutaneous, trapezius, rhomboid, serratus posterior superior and intercostal muscles. The needle will be introduced with in plane approach, from caudal to cranial and 30 ml of 0.25% bupivacaine will be injected in the fascial plane between serratus posterior superior and intercostal muscles at the level of second and third ribs.

PECS II group With the patient in supine position, the ipsilateral upper arm will be abducted and externally rotated. Under complete aseptic technique, a high frequency linear probe will be placed in the infraclavicular region, angulated and directed laterally towards the axilla to visualize the third and fourth ribs with pectoralis major, minor and serratus anterior muscles from superficial to deep. The needle will be introduced with in plane approach from medial to lateral, 10 ml of 0.25% bupivacaine will be injected in the fascial plane between pectoralis major and pectoralis minor then the needle will be further introduced to the fascial plane between pectoralis minor and serratus anterior muscles with injection of 20 ml of 0.25% bupivacaine.

After extubation, the patients will be transferred to PACU (Post-Anesthesia Care Unit) for monitoring. Numerical rating scale (NRS) will be used for pain assessment while 0 is no pain and 10 is severe agonizing pain. Patients will be given a rescue analgesia of 0.05 mg / kg morphine if NRS ≥ 4 and repeated if needed. Intravenous 1 gm paracetamol every 8 h and 30 mg ketorolac (if not contraindicated) every 12 h will be given regularly.