PENG Block: Indications, Techniques, and Contraindications
The PENG (Pericapsular Nerve Group) block is a promising regional anesthesia technique primarily indicated for hip surgeries that targets sensory branches of the femoral, obturator, and accessory obturator nerves innervating the anterior capsule of the hip joint, providing effective pain relief while preserving motor function.
Indications
Primary Indications:
- Hip fracture pain management 1
- Total hip arthroplasty (THA) 2
- Particularly effective for anterior approach THA 2
- Hip arthroscopy procedures 3
Secondary Indications:
- Adjunct for shoulder surgery analgesia (emerging application) 4
- Complementary block for multimodal pain management in hip procedures 5
Technique
Anatomical Target:
- Sensory branches of the femoral, obturator, and accessory obturator nerves 1
- These nerves innervate the anterior capsule of the hip joint 1
Equipment Required:
Procedural Steps:
- Patient Positioning: Supine position
- Probe Placement: Linear ultrasound probe placed in transverse orientation over the anterior inferior iliac spine
- Anatomical Identification:
- Identify the iliopsoas muscle, iliopubic eminence, and femoral vessels
- Locate the musculofascial plane between the psoas tendon and pubic ramus
- Needle Insertion:
- In-plane approach from lateral to medial
- Advance needle tip to the space between the anterior inferior iliac spine and iliopubic eminence
- Injection:
- Inject 20mL of local anesthetic between the psoas tendon and pubic ramus 2
- Ensure proper spread of local anesthetic in this plane
Modifications:
- For complete hip analgesia, consider combining with Posterior Hip Pericapsular Block (PHPB) to cover the posterior capsule 6
Contraindications
Absolute Contraindications:
- Patient refusal
- Infection at the injection site
- Allergy to local anesthetics
- Patients on P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor) 1
- These medications must be discontinued 5-7 days before the procedure if PENG block is considered essential
Relative Contraindications:
- Coagulopathy or therapeutic anticoagulation
- Anatomical abnormalities in the target area
- Previous surgery at the injection site
- Severe cardiorespiratory disease with limited reserve
Advantages
- Preserved Motor Function: Minimal to no quadriceps weakness compared to femoral nerve blocks 5
- Opioid Reduction: Significant decrease in 24-hour opioid consumption after hip surgery 5
- Improved Recovery: Associated with reduced hospital length of stay in THA patients 2
- Better Patient Satisfaction: Higher satisfaction scores compared to conventional analgesic approaches 5
- Prolonged Analgesia: Extended time to first request for rescue analgesia 5
Limitations and Considerations
- Incomplete Posterior Coverage: PENG block primarily targets anterior hip capsule; may need supplementation for posterior hip pain 6
- Variable Efficacy: Not consistently effective for all hip procedures (e.g., mixed results in hip arthroscopy) 3
- Technical Considerations:
- Requires ultrasound guidance for precise placement 7
- Should be performed by practitioners experienced with ultrasound-guided regional techniques
- Proper needle visualization is essential to avoid vascular injury
Safety Considerations
- Use ultrasound guidance to minimize risk of vascular puncture 7
- Aspirate before injection to avoid intravascular administration
- Monitor for signs of local anesthetic systemic toxicity
- For patients on aspirin monotherapy, PENG block may be performed if benefit/risk ratio is favorable 1
- Consider the block a high bleeding risk procedure due to proximity to femoral vessels 1, 7
The PENG block represents an evolving technique in regional anesthesia that offers effective analgesia for hip procedures while preserving motor function, potentially facilitating earlier mobilization and rehabilitation.