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@charter.net Lecture 17

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.

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.

3-in-1 Block

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

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

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.

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.

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.

Femoral Triangle

Anatomy

Pectineous muscle

Iliopsoas muscle

Fascia iliaca

Fascia lata

Skin

Femoral Vein

Femoral Artery

Femoral Nerve

Anatomy

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.

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

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.

Anatomy

Contraindications

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

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.

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.

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.

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.)

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.

Local Anesthetics

FNB = 15-20 ml of local 3-in-1 NB = 25-30 ml of local Use 1:200,000 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

Complications

Intravascular injection Local anesthetic toxicity Nerve trauma Prolonged motor blockade of the

muscles of the thigh Hematoma formation Block failure

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.

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

Controversy “Is there really a sheath”

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

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 Miller’s 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.