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

Campus Bio-Medico University of Rome

Status: Not yet enrolling

Conditions: Postoperative Pain Management After Total Hip Arthroplasty; Total Hip Arthroplasty (THA)

Treatments: Procedure: Magnetic resonance imaging; Procedure: PENG Block

Study type: Interventional

Funder types: Other

Identifiers

NCT07040423

Policlinico Campus Bio-Medico

Details and patient eligibility

About

This study uses MRI imaging to evaluate the spread of local anesthetic following the administration of a pericapsular nerve group (PENG) block. The goal is to determine whether a distinct fascial plane exists between neurovascular structures, potentially explaining the block's observed clinical effectiveness.

Full description

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.

Enrollment: 6 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients scheduled for total hip replacement surgery
• Age ≥ 18 years
• ASA physical status classification I-III
• Signed informed consent obtained
• Orthopedic indication for preoperative MRI study

Exclusion criteria

• Allergy to local anesthetics
• Infection at the planned puncture site
• Refusal or inability to provide informed consent
• Age < 18 years
• Claustrophobia
• Altered consciousness or severe dementia
• Presence of MRI-incompatible implanted devices (e.g., pacemakers implanted before 2000)
• Pregnancy or breastfeeding

Trial design

Primary purpose: Supportive Care

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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6 participants in 1 patient group

PENG Block with MRI-Based Local Anesthetic Spread Assessment

Experimental group

Description:

All patients receive standardized multimodal analgesia before surgery. Patients in this arm receive an ultrasound-guided PENG block in the supine position under sterile conditions. A low-frequency (2-5 MHz) curvilinear probe is placed above the AIIS and rotated \~45° to align with the pubic ramus. Using an in-plane lateral-to-medial approach, a 10 cm, 20G needle is advanced to the interfascial plane between the iliopsoas tendon and pubic ramus. After negative aspiration, ropivacaine hydrochloride 0.5% is injected in 5 mL increments up to 20 mL, observing spread via ultrasound. A pelvic MRI is then performed to assess anesthetic diffusion before the patient proceeds to total hip arthroplasty.

Treatment:

Procedure: PENG Block

Procedure: Magnetic resonance imaging