Can a block of the inferolateral genicular nerve cause injury to the common peroneal nerve?

Risk of Common Peroneal Nerve Injury During Inferolateral Genicular Nerve Block

Inferolateral genicular nerve block can potentially cause injury to the common peroneal nerve due to their close anatomical proximity, requiring careful technique and ultrasound guidance to minimize this risk. 1

Anatomical Considerations

The inferolateral genicular nerve is anatomically situated in close proximity to the common peroneal nerve as it courses around the fibular head. This anatomical relationship creates a potential risk zone during interventional procedures targeting the inferolateral genicular nerve.

Key anatomical points:

• The inferolateral (recurrent) branch from the common peroneal nerve innervates part of the anterior knee capsule 1
• The common peroneal nerve is superficial and vulnerable to injury at the level of the fibular head 2
• The inferolateral peroneal nerve branch is located too close to the common peroneal nerve, making it a high-risk target for radiofrequency ablation 1

Risk Assessment

The risk of common peroneal nerve injury during inferolateral genicular nerve procedures is significant due to:

1. Anatomical proximity: The inferolateral genicular nerve branch is closely related to the main common peroneal nerve trunk
2. Superficial location: The common peroneal nerve is particularly vulnerable as it passes around the fibular head 2
3. Serious consequences: Injury to the common peroneal nerve produces considerable disability including foot drop and sensory deficits 3

Prevention Strategies

To minimize the risk of common peroneal nerve injury during genicular nerve procedures:

Imaging Guidance

• Ultrasound guidance is strongly recommended to visualize neural structures and improve accuracy 4
• Ultrasound allows direct visualization of the nerve and surrounding structures, reducing the risk of inadvertent injury
• Well-aligned radiographs are critical to guide lesion placement when using fluoroscopy 1

Technical Considerations

• Use appropriate anatomical landmarks: For medial genicular nerves, the adductor tubercle (SMGN) and medial collateral ligament (IMGN) serve as reliable landmarks 4
• Consider alternative approaches that avoid the inferolateral genicular nerve due to its proximity to the common peroneal nerve 1
• Use small volumes of injectate to minimize spread to adjacent structures 5

Monitoring

• Thorough testing for block success should be performed before proceeding with any ablative procedure 6
• Monitor for early signs of nerve injury, including unexpected sensory or motor deficits

Management of Suspected Injury

If common peroneal nerve injury is suspected:

1. Early recognition: Assess for foot drop, sensory changes in the lateral leg and dorsum of foot
2. Immediate evaluation: Perform a thorough neurological examination
3. Imaging: Consider MRI of the affected area if neurological deficits are present 6
4. Specialist referral: Prompt referral to neurology or neurosurgery for persistent deficits

Clinical Implications

The risk of common peroneal nerve injury during inferolateral genicular nerve block has important implications:

• Consider avoiding the inferolateral genicular nerve target in favor of other genicular nerve branches when performing ablative procedures 1
• Alternative approaches targeting multiple other genicular nerve branches may provide adequate pain relief while avoiding this high-risk area 7
• When performing genicular nerve procedures, practitioners should be vigilant about monitoring for signs of common peroneal nerve injury

The close anatomical relationship between the inferolateral genicular nerve and the common peroneal nerve creates an inherent risk during interventional procedures. Careful technique, appropriate imaging guidance, and thorough anatomical knowledge are essential to minimize the risk of this potentially debilitating complication.