Clinical Research Directory

Group E: The block will be performed preoperatively with full aseptic precautions. The ultrasound probe will be placed on the back in a vertical orientation on the lateral side of the posterior median line to identify the transverse process of the 5th thoracic vertebra and erector spine muscle. A skin wheal using 3ml of 1% lidocaine will be made 2 to 3 cm superior to the superior aspect of the transducer. The puncture will be performed using the intra-plane needling technique after local anaesthesia infiltration. A 20-gauge Tuohy needle connected to a syringe containing the anesthetic mixture or saline will be advanced. When the puncture needle touch the transverse process, with no blood, gas, or cerebrospinal fluid observed on aspiration, 20 mL of 0.25% bupivacaine will be administered between the erector spine muscle and transverse process. Local anesthetic diffusion between the transverse process and erector spinae muscle is an indication of a successful puncture.

Group M: The block will be performed preoperatively with full aseptic precautions. The ultrasound probe will be placed on the back in a vertical orientation on the lateral side of the posterior median line to identify the transverse processes of the 4th and 5th thoracic vertebrae and pleura. A skin wheal using 3ml of 1% lidocaine will be made 2 to 3 cm superior to the superior aspect of the transducer. Using the in plane needling technique in the space between the transverse processes of the 4th and 5th thoracic vertebrae, the puncture needle needle tip will be placed at the mid-point between the transverse process and pleura, with no blood, gas, or cerebrospinal fluid observed on aspiration, 20 mL of 0.25% bupivacaine will be administered. The local anesthetic spread will be noted in the area midway between the transverse process and pleura is an indication of a successful puncture.