Saphenous nerve blocks Flashcards
What size needle should be used?
25 gauge, 2-3 inch needle
What size transducer should be used?
High frequency 8-12MHz linear array
Describe the saphenous nerve
Sensory branch of femoral n L3-4 dermatomes Splits distal to inguinal ligament Travels w/ femoral artery & vein Passes through adductor canal Travels posterior medial and branches
What are the borders of the adductor canal?
Lateral: vastus medialis
Medial: sartorius
Inferior: adductor longus
Where if the saphenous nerve vulnerable to injury?
The infrapatellar division as it pierces the sartorius muscle vulnerable to injury against prominence of medial femoral condyle
esp during knee surgery or arthroscopy
What does the cutaneous saphenous nerve supply?
Anterior tibia, medial leg and foot medial to hallux
How can the distal saphenous nerve be injured?
Saphenous vein surgery
High or medial ankle sprain
What is saphenous nerve syndrome?
Entrapment and neuralgia of saphenous nerve as it courses through the adductor (Hunter’s) canal in the medial thigh or distally at the medial knee (infrapatellar branches)
What is an indication for saphenous nerve injection?
Recalcitrant neuropathic pain
How much steroid and local anesthetic should be used in injection?
1 mL steroid and 2-3 mL local anesthetic
What is the transducer position for injection?
Anatomic axial plane short axis to saphenous nerve
Where should injection be localized?
+ Tinel’s sign location
Area of focal tenderness
Perineural circumferential spread around saphenous nerve
