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Geniculate Nerve Injection

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(Redirected from Geniculate Nerve Block)

Other Names

  • Geniculate Nerve Injection
  • Geniculate Nerve Block

Background

Innervation of the knee. The origin of the superomedial and superolateral genicular nerves (from the sciatic nerve or from the femoral nerve) is controversial[1]

Key Points

  • Useful to treat chronic pain, provide regional anesthesia after knee surgery
  • Since it targets only sensory branches, the quadriceps muscle is preserved
  • Transducer: high frequency, linear
  • Needle: 2.5 - 3.5 inch, 20-22 gauge

Anatomy of the Genicular Nerves

  • Composed of branches of femoral nerve, obturator nerve, sciatic nerve with significant anatomic variance
  • Can loosely be broken into 4 quadrants in the anterior knee:
    • Superomedial branch
    • Superolateral branch
    • Inferolateral branch
    • Inferomedial branch
  • Provide sensory innervation only, no motor innervation

Palpation Guidance vs Ultrasound Guidance

  • This procedure can not be safely or reliably performed by landmark guidance
  • There are no papers comparing landmark to ultrasound guidance
  • One small cadaveric study showed ultrasound guidance to be accurate[2]

Indications

Contraindications

  • Absolute
    • Anaphylaxis to injectates
    • Overlying cellulitis, skin lesion or systemic infection
  • Relative
    • Can be treated with less invasive means
    • Hyperglycemia or poorly controlled diabetes
    • Lack of symptom improvement with previous injection

Procedure

Sonoanatomy of the genicular nerves in a coronal plane. SLGA, superolateral genicular artery; SMGA, superomedial genicular artery; ILGA, inferolateral genicular artery; IMGA, inferomedial genicular artery. (A) Transducer position and sonoanatomy of the superomedial genicular nerve. (B) Transducer position and sonoanatomy of the inferomedial genicular nerve. (C) Transducer position and sonoanatomy of the superolateral genicular nerve. (D) Transducer position and sonoanatomy of the inferolateral genicular nerve.[1]
Reverse ultrasound anatomy of the genicular nerves showing needle insertion and distribution of the local anesthetic. SLGN, superolateral genicular nerve, and artery; SMGN, superomedial genicular nerve, and artery; ILGN, inferolateral genicular nerve, and artery; IMGN, inferomedial genicular nerve, and artery.[1]
Transducer and needle position blockade of: (A) superomedial genicular nerve (SMGN); (B) superolateral genicular nerve (SLGN); (C) inferomedial genicular nerve (IMGN); and (D) the nerve to vastus intermedius (NVI). Dotted line represents outline of patella. Green arrow = needle trajectory and end-point. Pink arrow = genicular artery[3]
Superomedial genicular nerve block pre-injection (A) and post-injection (B), showing the spread of local anesthetic (blue arrow) along the cortex of the distal femur[3]

Equipment

  • Sterile prep (i.e. chloraprep, chlorhexidine, iodine, etc)
  • Gloves
  • Needle: typically 21-25 gauge, 1.5 inch
  • Syringe: 5-10 mL
  • Gauze
  • Ethyl Chloride
  • Bandage
  • Injectate
    • Local anesthetic
    • Corticosteroid
  • Sterile probe cover

Identifying Sonographic Landmarks

  • Superolateral Geniculate Nerve
    • Place the transducer in the coronal plane over the lateral femoral condyle
    • Move proximally to visualize the metaphysis
    • Superlateral genicular artery/ nerve can be seen between the deep fascia of vastus lateralis, femur
  • Superomedial Geniculate Nerve
    • Place the transducer in the coronal plane over the medial femoral condyle
    • Slide transducer slightly proximal, visualize the metaphysis just anterior to adductor tubercle
    • Superomedial geniculate artery/ nerve can be seen at this level between deep fascia of vastus medialis, femur
  • Inferolateral Geniculate Nerve
    • Place the transducer in the coronal plane over the lateral, distal knee
    • Identify the lateral femoral condyle, slide distally to the head of the fibula
    • Inferolateral genicular artery/ nerve can be seen between the lateral collateral ligament, lateral tibial plateau
    • Avoided in some protocols due to proximity to common peroneal nerve and increased risk of foot drop
  • Inferomedial Geniculate Nerve
  • Recurrent Peroneal Nerve
    • Optional but can also be blocked
    • Place the transducer in the coronal plane over the anterolateral distal knee
    • Visualize the junction of the lateral tibial plateau anterior to the fibula
    • The recurrent tibial artery/ recurrent peroneal nerve can be visualized superficial to the bone
  • Nerve to Vastus Intermedius
    • Place the transducer about 3 cm superior to the patella in the transverse plane
    • Identify the femur in short axis

Technique

  • Patient Position
    • Supine, knee in neutral position
    • Transducer is long axis to the bony landmarks
  • Needle Approach/ Orientation
    • In plane or out of plane
  • Target
    • Each individual nerve (and artery adjacent to it)
  • Pearls and Pitfalls
    • This procedure involves blocking multiple nerves
    • Once the target is identified, you can rotate the probe into either a short or long axis
    • This allows an in-plane or out-of-plane approach

Aftercare

  • Motor exam should be intact
  • No major restrictions in most cases
  • Can augment with ice, NSAIDS
  • Consider Knee Compression Sleeve

Complications

  • Infection
  • Damage to surrounding tissue

See Also

References

  1. ↑ 1.0 1.1 1.2 Image courtesy of nysora.com
  2. ↑ Evren Yasar, M. D., et al. "Accuracy of ultrasound-guided genicular nerve block: a cadaveric study." Pain physician 18.5 (2015): E899-E904.
  3. ↑ 3.0 3.1 Image courtesy of asra.com
Created by:
John Kiel on 5 December 2024 18:57:03
Authors:
Last edited:
5 December 2024 20:39:41
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