A Randomized Controlled Study Comparing Thoracic Paravertebral Block to Serratus Anterior Plane Block in Breast Surgery

•The blocks techniques:

• Group I: Thoracic paravertebral block group (TPVB group n=15) These patients will receive single ipsilateral ultrasound-guided thoracic paravertebral block. TPVB will be performed with the patient in the sitting position at the level of the 4th thoracic vertebra under complete aseptic precaution with the probe in a vertical position approximately 2.5-3 cm lateral to the midline. The midpoint of the transducer is to be placed in a longitudinal paramedian plane between two transverse processes. Both transverse processes should be visualized, with the superior costo-transverse ligament and the pleura visible in between .An 18-20 gauge Tuohy needle will be introduced in a cephalad direction. The tip of the needle will be advanced under direct visualization until it pierces the superior costo-transverse ligament. the investigators will inject small aliquots of normal saline intermittently as the investigators advance the needle to confirm the position of the tip. When the needle tip is located immediately above the pleura, the needle is aspirated to confirm the absence of blood or air. After this, 15-20 cc of bupivacaine 0.25% will be injected. Spread of local anaesthetic with depression of the pleura will be clearly visualized. The extent of local anaesthetic spread should be evaluated by moving the ultrasound probe superiorly and inferiorly.
• Group II :Serratus anterior plane block group (SAP group n= 15) These patients will receive serratus anterior plane block. The SAP block will be performed while the patient is in the supine position by using a linear US probe of high frequency (6-13 MHz) after sheathing. The probe will be placed over the mid-clavicular region of the thoracic cage in a sagittal plane. The ribs will be counted inferiorly and laterally, until the 5th rib is identified in the midaxillary line. The latissimus dorsi (superficial and posterior), teres major (superior) and serratus muscles (deep and inferior) will be then easily identifiable by ultrasound overlying the fifth rib. The needle (Stimuplex, B Braun, Germany 22-G, 50-mm) will be introduced in-plane with respect to the ultrasound probe from supero-anterior to postero-inferior. Under continuous ultrasound guidance, the investigators will inject 20 cc of bupivacaine 0.25%. The sensory level will be tested with pin prick and ice pack before induction of general anesthesia