Pubic Symphysis Injection

Other Names

• Pubic Symphysis Injection

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Background

Pubic Symphysis

Key Points

• Needle: 22-25 gauge, 1.5 inch
• Transducer: high frequency, linear array
• Can have resistance to injectate due to the fibrocartilage disc

Anatomy of the Pubic Symphysis

• Nonsynovial amphiarthrodial joint connecting the left and right superior rami of the pelvis.
• Anterior portion of the joint is 3–5 mm wider than the posterior portion
• Joint connected by fibrocartilage, surrounded by ligaments
• Superior and inferior ligaments provide most of the joint’s stability
• Normal adults: approximately 2 mm of translation, 1 degree of rotation

Palpation vs Ultrasound Guided

• A technique for palpation guided injection of the pubic symphysis has been described
• Desmond and Harmon have described the ultrasound guided approach
• However, no studies have compared ultrasound- vs palpation-guided techniques

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Indications

• Osteitis Pubis

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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

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Procedure

Long axis, out of plane technique. Needle and probe position

Long axis, out of plane technique ultrasound view with needle trajectory marked

Short axis, in plane technique with needle and probe position

Short axis, in plane technique ultrasound view with needle trajectory marked

a, b Graphic illustration (a) and short-axis US image (b) demonstrate the out-of-plane approach with the transducer (blue rectangle in A) perpendicular to the joint and the needle (arrow in B) inserted from a cranial to caudal direction (P = pubic bones). Note how the echogenic dot of the needle can mimic an osteophyte or bone irregularity (arrowhead in B) in this approach.

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

Ultrasound Findings

• Best visualized in long axis with the high frequency, linear array transducer
• Depth is usually less than 3 cm (depends on body habitus)
• Common findings include:
  • Thickening of the superior joint capsule
  • Cortical irregularities
  • Widening of the joint
  • Enthesopathies of the superior ligament

Technique: Long Axis, Out of Plane (recommended technique)

• Patient Position
  • Supine
• Transducer position
  • Long axis over the pubic symphysis (transverse plane)
• Needle Approach/ Orientation
  • Out of plane
  • Anterosuperior to posteroinferior
• Target
  • Anterior pubic symphysis joint
• Pearls and Pitfalls
  • Use a step-wise/ walk down technique
  • This is a nonsynovial joint, will need to inject into the fibrocartilage disc
  • Will feel like injecting into a block of cheese
  • May require larger needle (20-22 gauge) to puncture
  • Shaving the site makes the procedure easier
  • Do not puncture posterior to the joint

Technique: Short Axis, In Plane

• Patient Position
  • Supine
• Transducer position
  • Short axis over the pubic symphysis (sagittal plane)
• Needle Approach/ Orientation
  • In plane
  • Anterosuperior to posteroinferior
• Target
  • Anterior pubic symphysis joint
• Pearls and Pitfalls
  • Best performed with a gel stand off
  • May require longer needle in plane
  • See pearls and pitfalls for out of plane technique above

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Aftercare

• No significant restrictions
• Can augment with ice, NSAIDS

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Complications

• Skin: Subcutaneous fat atrophy, skin atrophy, skin depigmentation
• Painful local reaction
• Infection
• Hyperglycemia
• Tendon, nerve or blood vessel injury

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See Also

Internal

• Procedures Main
• Ultrasound Main
• Hip Pain Main

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