Femoral Nerve Blocks and 3-in-1 Nerve Blocks

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Femoral Nerve Blocks and3-in-1 Nerve Blocks
Soli Deo Gloria

• Developing Countries Regional Anesthesia Lecture
  Series
• Daniel D. Moos CRNA, Ed.D. U.S.A.
  moosd_at_charter.net

Lecture 17
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Disclaimer

• Every effort was made to ensure that material and
  information contained in this presentation are
  correct and up-to-date. The author can not
  accept liability/responsibility from errors that
  may occur from the use of this information. It
  is up to each clinician to ensure that they
  provide safe anesthetic care to their patients.

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Introduction

• Currently underutilized for clinical anesthesia
  and postoperative pain management.
• Lower extremity peripheral nerve blocks have
  historically been performed less frequently than
  peripheral nerve blocks of the upper extremities.

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3-in-1 Block

• Suppose to block the femoral nerve, lateral
  femoral cutaneous nerve, and obturator.

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Indications for FNB/3-in-1 Block

• Operations of anterior thigh (lacerations, skin
  grafts, muscle biopsy)
• Pin or plate insertion at the upper femur
• Femur fractures
• Analgesia of hip (dislocations, femoral nerve
  fractures)
• Analgesia of the knee

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Limitations- Knee

• Not complete analgesia of the knee. The knee is
  innervated by the femoral, obturator, and sciatic
  nerve.
• These blocks will create a motor block of the
  quadriceps.

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Limitations- Hip

• Hip is innervated by the femoral, obturator, and
  lateral femoral cutaneous nerve.
• A small contribution comes from the sciatic but
  should not be significant.

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Anatomy

• The femoral nerve is the largest branch of the
  lumbar plexus.
• Femoral nerve is created from contributions from
  L2, L3, and L4.
• The femoral nerve enters into the thigh under the
  inguinal ligament, between the psoas and iliacus
  mucle.

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Femoral Triangle
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Anatomy
Skin
Femoral Artery
Fascia lata
Femoral Vein
Femoral Nerve
Fascia iliaca
Iliopsoas muscle
Pectineous muscle
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Anatomy
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Femoral Nerve sheath

• Contains the femoral nerve and artery
• It is located between the psoas and iliacus
  muscle.
• It is located below the fascia iliaca.

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Lateral Femoral Cutaneous Nerve and Obturator
Nerves

• Lateral femoral cutaneous nerve is formed by
  contributions from L2 and L3
• Obturator nerve is formed by contributions from
  L2, L3, and L4

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Innervations

• Femoral Nerve anterior and medial portion of the
  thigh (sartorious, pectineus, quadriceps)
  cutaneous portion of medial and lateral thigh
  periosteum of the femur. The posterior division
  of the femoral nerve will become the saphenous
  nerve.
• LFCN purely sensory to lateral buttock, thigh,
  and knee joint.
• Obturator Nerve sensory to medial thigh, hip
  joint, and adductor muscles.

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Anatomy
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Contraindications

• Burn or infection at the injection site
• Coagulopathy
• Vascular graft
• Neurological disease (relative)
• Patient refusal
• Local anesthetic allergy

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Technique

• Same for either block
• Locate the anterior superior iliac spine and the
  pubic tubercle. A line between these two
  structures is where the inguinal ligament is
  located.
• Just below this line is the femoral nerve.

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Technique

• Palpate the femoral artery
• The femoral nerve should be located 1 cm lateral
  to the palpation.
• Medial to lateral the structures are femoral
  vein, artery, and nerve.

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Technique

• For paresthesia technique a blunted needle should
  be used.
• Insert perpendicular while aspirating for blood
• Once paresthesia is elicited pull back slightly
  and inject. There should be no pain.
• If you are at a depth of 4-5 cm pull back and
  start over.
• As with any peripheral nerve block frequent
  aspiration is mandatory.

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Technique 2 pop technique

• Blunted needle
• A slight increase in resistance followed by a
  loss of resistance indicates that you have
  transversed the fascia lata.
• A second increase in resistance followed by a
  loss of resistance indicates that you have
  transversed fascia iliaca.
• Deposit local anesthetic. (aspirate, make sure
  no pain, etc.)

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Technique Nerve Stimulator

• 2 inch, 22 gauge needle (insulated)
• 2 cm lateral to femoral pulse, 2 cm down from
  inguinal ligament.
• Identify quadriceps contraction
• Reduce stimulation to 0.5 mA and adjust needle
  for continued quad contraction.
• Injection of 1 ml of local anesthetic should see
  the contractions start to fade.

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Local Anesthetics

• FNB 15-20 ml of local
• 3-in-1 NB 25-30 ml of local
• Use 1200,000 epi containing solutions or add
  yourself.
• 1-2 lidocaine will have an onset of 10-20
  minutes and last 2-5 hours for anesthesia up to
  8 hours for analgesia.
• Bupivacaine will have an onset of 15-30 minutes
  and last up to 5-15 hours for anesthesia and up
  to 30 hours for analgesia

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Complications

• Intravascular injection
• Local anesthetic toxicity
• Nerve trauma
• Prolonged motor blockade of the muscles of the
  thigh
• Hematoma formation
• Block failure

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Differences between FNB and 3-in-1 Nerve Block

• Volume 20 ml or less for FNB 25-30 ml of 3-in-1
  Nerve Block
• More volume more spread
• Pressure applied distally to the injection site
  will help the spread of local anesthetic further
  up to the lateral femoral cutaneous nerve and
  LFCN.

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Controversy

• Studies have found that the 3-in-1 nerve block
  inconsistently blocks the obturator nerve
  (4-78) depending on volume (up to 40 ml).
• Most likely the 3-in-1 nerve block will
  consistently block the FN and LFCN

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Controversy Is there really a sheath

• Cadaver studies have found no conclusive evidence
  that there is a femoral sheath.

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References

• Burkard J, Lee Olson R., Vacchiano CA. Regional
  Anesthesia. In Nurse Anesthesia 3rd edition.
  Nagelhout, JJ Zaglaniczny KL ed. Pages
  977-1030.
• Morgan, G.E. Mikhail, M. (2006). Peripheral
  nerve blocks. In G.E. Morgan et al Clinical
  Anesthesiology, 4th edition. New York Lange
  Medical Books.
• Moos, D.D. Cuddeford, J.D. (1998). AANA
  Journal Course for nurse anesthetists- Femoral
  nerve block and 3-in-1 nerve block in anesthesia.
  AANA Journal volume 66 issue 4.
• Wedel, D.J. Horlocker, T.T. Nerve blocks. In
  Millers Anesthesia 6th edtion. Miller, RD ed.
  Pages 1685-1715. Elsevier, Philadelphia, Penn.
  2005.
• Wedel, D.J. Horlocker, T.T. (2008). Peripheral
  nerve blocks. In D.E. Longnecker et al (eds)
  Anesthesiology. New York McGraw-Hill Medical.