MRI-Based Assessment of Local Anesthetic Spread in the PENG Block Compartment

The pericapsular nerve group (PENG) block has demonstrated promising clinical results in providing analgesia for hip-related pain, particularly in patients with femoral neck fractures or undergoing hip surgery. However, the exact mechanism of action and spread of local anesthetic remain poorly understood. This pilot study aims to use magnetic resonance imaging (MRI) to visualize the distribution pattern of the injectate after PENG block administration. High-resolution MRI scans will be obtained shortly after the procedure to assess the spatial relationship between the spread of local anesthetic, relevant anatomical structures (including the iliopsoas muscle, femoral artery, and femoral nerve), and potential fascial compartments. The findings will help to clarify the anatomic basis of the PENG block and may guide optimization of technique for enhanced clinical outcomes.