Effects of Injection Volume and Site on Sensory Distribution After Rectus Sheath Block

This randomized controlled study aims to evaluate the effects of local anesthetic injection volume and injection site on cutaneous sensory distribution following ultrasound-guided rectus sheath block (RSB). Participants undergoing laparoscopic abdominal surgery will be randomized to receive RSB using different injection sites and volumes (20 mL or 30 mL per side). Injection sites will be selected according to the surgical location, including upper, middle, or lower rectus sheath approaches. Cutaneous sensory distribution will be assessed to determine the extent and pattern of sensory blockade associated with each technique. The findings may help optimize injection techniques and local anesthetic volumes to achieve adequate sensory coverage for abdominal surgery.