Ultrasound-Guided T2 Erector Spinae Plane Block Versus Intercostobrachial Block in AV Fistula Surgery.

Arteriovenous fistula (AVF) superficialization is an essential procedure for patients with end-stage renal disease . The supraclavicular brachial plexus block is commonly used for upper extremity surgeries .Because the ICBN originates from the T2 nerve root below the C5-T1 nerve roots comprising the brachial plexus, brachial plexus blocks are ideally supplemented with an ICBN infiltration block for medial upper arm coverage.The ICBB requires precise ultrasound guidance to target the ICBN, which is small and variably located, making it technically challenging and time-intensive.

ESP block at T2 level can provide broad coverage, ease of Performance, superficial injection and requiring less technical expertise compared to the ICBB .

The patients are randomly allocated into 2 groups :

1. Erector spinae plane block group (Group ESP): will receive 10 ml of 0.5% bupivacaine injected into the erector spinae plane at T2 level under ultrasound guidance.
2. Intercostobrachial block group (Group ICBB): will receive 10 ml of 0.5% bupivacaine injected around intercostobrachial nerve under ultrasound guidance. • Standard Supraclavicular Brachial plexus Block will be performed for all patients using 20 ml of 0.5% bupivacaine under ultrasound guidance.

• Ultrasound Guided Intercostobrachial Nerve Block (Procedure), also known as ICBB: 1. Position: patient supine with arm abducted. 2. Ultrasound setup: High frequency probe positioned at upper axillary region. 3. Technique: Needle will be advanced into subcutaneous tissue, in-plane to target intercostobrachial nerve near axillary artery. 4. Drug: 10 ml of 0.5% bupivacaine.
• Ultrasound Guided Erector Spinae Plane Block at T2 level (Procedure): 1. Position: patient sitting or in lateral decubitus. 2. Ultrasound setup: High frequency linear transducer will be placed in a parasagittal 2-3 cm lateral to spinous process at T2 level, erector spinae muscles will be identified superficial to the tip of T2 transverse process, patient's skin anesthetized with 3 ml of 2 % lidocaine subcutaneously, the tip of the 22- gauge 80-mm block needle(Sonoplex, Pajunk Medical, Geisingen, Germany) needle will be placed into the facial plane on the deep (anterior) aspect of erector spinae muscle. location of needle tip will be confirmed by visible fluid spread lifting the erector spinae muscle off the bony shadow of the transverse process then 10 ml of 0.5% bupivacaine will be injected into the facial plane that will be confirmed by visible hydrodissection .

Primary outcomes

• Proportion of Participants Achieving Complete Sensory Blockade Without Discomfort, Sedation, or Conversion to General Anesthesia [30 minutes after completion of the block procedure]: Complete sensory blockade was assessed 30 minutes after completion of the block procedure. Success was defined as achievement of adequate sensory blockade without patient discomfort requiring rescue sedation and without conversion to general anesthesia. The outcome was recorded as the number and proportion of participants meeting all success criteria in each treatment group.

Secondary outcomes

• Time to achieve complete sensory blockade. [From completion of block placement until complete sensory blockade is achieved, assessed up to 30 minutes.]: Time, in minutes, from completion of block placement to achievement of complete sensory blockade, as assessed by the study's sensory-testing procedure.
• Patient's satisfaction (assessed using Likert scale). [At 24 hours; the postoperative assessment.]: Patient satisfaction assessed using the 5-point Likert scale and the EVAN-LR perioperative satisfaction questionnaire, as specified in the study protocol. The scoring range, interpretation of higher scores, and whether both measures were analyzed separately should be explicitly stated.
• Total opioid consumption in 24 hours [in the first 24 hours]: Total opioid consumption in 24 hours postoperative in mg /kg
• The visual analog scale(VAS) [in the first 12 hours]: measure a patient pain intensty ,commonly used interpretation is 0:no pain,1-3 :mild pain.4-6:moderate pain,7-10 :sever pain

Sex: All, ages: 18 Years to 65 Years

Inclusion Criteria:

* • Adults scheduled for upper extremity surgeries under regional anesthesia.

  * Age: 18-65 years.
  * American society of Anesthesiologists (ASA) III.
  * Body Mass Index (BMI) < 35 kg/m².

Exclusion Criteria:

* •Allergy to local anesthetics.

  * Coagulopathy or infection at injection sites.
  * Pre-existing neuropathy or significant psychiatric disorders.
  * Pregnant or lactating women.