Deep Branch of the Radial Nerve Injection

Other Names

• Radial Nerve Hydrodissection

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Background

Illustration of deep branch of the radial nerve

• This page refers to ultrasound guided injection around the radial nerve

Key Points

• Use a high frequency, linear transducer and a 22- to 25-guage, 2 inch needle
• The deep branch is located between the deep and superficial heads of the supinator
• Can take significant volume to decompress nerve (15-20 mL)
• Consider diagnostic nerve block to distinguish from lateral epicondylalgia

Anatomy of deep branch of the radial nerve (DBRN)

• Courses between deep and superficial heads of the supinator
  • Becomes the posterior interosseous nerve once it exits the supinator
  • PIN and DBRN are often used interchangeably
• Vulnerable to entrapment at:
  • Most commonly at the arcade of Frohse (AF)
  • May be entrapped as it courses through or exits the supinator
  • By recurrent radial artery (leash of Henry)
  • Medial aspect of the extensor carpi radialis brevis
  • Capsule-tendon aponeurosis of the humeroradial joint

Palpation Guidance vs Ultrasound Guidance

• This procedure can not be safely performed without ultrasound guidance

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Indications

• Radial Tunnel Syndrome
• Refractory Lateral Epicondylalgia
  • RTS commonly co-occurs
• Posterior Interosseus Nerve Syndrome

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Contraindications

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

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Procedure

Probe position in long axis of the radial nerve

Deep branch of the radial nerve (DBRN) between the two heads of the supinator in short-axis view.

Long-axis view of deep branch of the radial nerve (DBRN) at distal edge of supinator

Long-axis view of deep branch of the radial nerve (DBRN) during injection procedure

Equipment

• Sterile including chloraprep, chlorhexadine, iodine
• Gloves
• Needle: typically 21-25 gauge, 1.5 inch
• Syringe: 5-10 mL
• Gauze
• Ethyl Chloride
• Bandage
• Injectate
  • Local anesthetic
  • Corticosteroid
• Sterile probe cover

Ultrasound Findings

• The DBRN can be identified with ultrasound imaging
• Specific norms for cross sectional area of the DBRN have not been established
• Cartwright et al: mean surface area for for the radial nerve at the antecubital fossa was 9.3 mm2, with a reference range of 4.5–14.3 mm
• Find the radial nerve:
  • Find radial nerve: short-axis, identify the radial nerve coming off the spiral groove at the mid-lateral humerus and follow it distally
  • Find radial nerve alternative: short-axis, identify the DBRN while performing a short-axis slide in the plane between the superficial and deep heads of the supinator muscle

Ultrasound Guided: Long Axis, In Plane

• Patient Position
  • Patient is seated, arm on table
  • Arm is flexed 20 degrees, thumb pointed towards the ceiling
• Transducer Position
  • Short axis to the DBRN at the target site (eg, AF)
• Needle Approach
  • In plane
  • May need to rotate probe out of plane for re-orientation
  • Distal to proximal
  • Target: DBRN mid supinator injecting toward AF
• Pearls and Pitfalls
  • Advanced technique, requires precision, constant needle tip visualization
  • Release entire DBRN: repeat the above procedure in a proximal to distal direction where the nerve exits the supinator muscle

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Aftercare

• Patient should be counseled on
  • Duration of anesthetic
  • Loss of motor function of extensor muscle groups

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Complications

• Intravascular injection
• Residual motor block
• Local trauma

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See Also

• Elbow Pain Main
• Procedures Main

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