Classic Versus Interfascial Axillary Block in Hand, Wrist, and Forearm Surgery

Overview

Hand, wrist, and forearm surgeries are commonly performed procedures with significant postoperative pain potential. Regional anesthesia of the brachial plexus via the axillary approach is one of the gold-standard techniques for distal upper-limb surgery. In the conventional (classic) axillary block, the median, ulnar, and radial nerves within the axillary sheath are individually targeted under ultrasound guidance; however, anatomical septations around the axillary artery may prevent homogeneous spread of local anesthetic, leading to a patchy block and reduced intraoperative success. The interfascial axillary block is a modified approach in which local anesthetic is deposited into the fascial planes between the axillary muscles rather than directly into the nerve sheath, aiming for passive diffusion, homogeneous spread, and fewer needle manipulations. This prospective, randomized, single-center study compares the classic axillary block with the interfascial axillary block in patients undergoing hand, wrist, and forearm surgery, primarily in terms of surgical anesthesia adequacy (block success).

This is a prospective, randomized, single-center clinical trial conducted in a Department of Anesthesiology and Reanimation. Randomization is performed using the sealed-envelope method. A total of 110 patients (55 per group) aged 18-90 years, American society of anesthesiologists physical status I-III, scheduled for elective hand, wrist, or forearm surgery under ultrasound-guided regional anesthesia will be enrolled. Group 1 (Classic Axillary Block) receives an ultrasound-guided block targeting the median, ulnar, and radial nerves perineurally/perivascularly within the axillary sheath. Group 2 (Interfascial Axillary Block) receives an ultrasound-guided injection of local anesthetic into the potential fascial planes between the axillary muscles, relying on passive diffusion. The primary outcome is surgical anesthesia adequacy (block success). Secondary outcomes include block application time, sensory and motor block onset, rates of additional local infiltration and conversion to general anesthesia, intraoperative additional analgesic/sedation requirements, hemodynamic parameters, patient and surgeon satisfaction, and complications.