Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric fascia iliac block. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.
List indications of performing a pediatric point-of-care ultrasound fascia iliaca nerve block (POCUS-FINB)
List the limitations of POCUS-FINB
Describe the technique for performing POCUS fascia iliaca nerve block
Identify anatomical landmarks accurately on POCUS
Calculate the maximum safe weight-based local anesthetic dose
Recognize the signs and symptoms of local anesthetic systemic toxicity (LAST) and describe the appropriate management
Case Introduction: Child with thigh pain
Sarah is a 3-year-old girl who comes into the emergency department complaining of acute thigh pain that started 30 minutes ago. She was playing on a trampoline when she accidentally fell off. She had immediate pain to the left thigh and she’s been unable to walk since the fall. Parents carried her in to the emergency department for further evaluation.
On arrival, her vital signs are:
Oxygen Saturation (room air)
She is in distress secondary to pain. She has a normal HEENT, neck, cardiac, respiratory, abdominal, and back examination. She points to her left anterior thigh when you ask her where her pain is. She has limited range of motion with flexion and extension of her left hip and complains of pain with any manipulation. Her leg is externally rotated and slightly shortened when compared to the opposite leg. She cries when you palpate any part of her leg, but is able to range her knee, ankle, and foot fully. She has 2+ dorsalis pedis and posterior tibialis pulses with intact sensation to light touch throughout.
Given her pain with range of motion at her hip and tenderness to palpation to the femur, you obtain a thigh radiograph, which shows a femoral shaft fracture. The orthopedic team is notified about the patient in order to discuss pain control and possible next steps. You ask your self several questions to help you best care for this child.
What can we do for pain control in this patient? Are there opioid-sparing options?
Can nerve blockade be utilized in this case?
What local anesthetic is appropriate, and what is a safe dose?
What safety precautions need to be considered for performing a regional block?
You consult with the orthopedic team and discuss performing a Point-of-Care Ultrasound-Guided Fascia Iliaca Nerve Block (POCUS-FINB).
Using ultrasonography to perform a fascia iliaca nerve block helps to identify key anatomical landmarks for appropriate administration of local anesthetic. The point-of-care ultrasound-guided fascia iliaca nerve block (POCUS-FINB) allows us to identify the area of interest, which is underneath the fascia iliaca fascial plane. Note that this plane is just deep to femoral artery and vein, in contrast to the fascia lata plane, which is superior to the femoral artery and vein (Figure 2). The area is best visualized distal to the inguinal canal and proximal to the bifurcation of the femoral artery.
Figure 2. Relevant anatomy for the fascia iliaca block for the right groin, demonstrating the location of the fascia iliaca and fascia lata planes (illustration by Dr. Muki Kangwa)
Table 1. Local anesthetic medications, their pharmacokinetics, and weight-based maximum dosages [1, 2]
A long-acting local anesthetic (e.g., ropivacaine or bupivacaine) is preferred for this block. Ropivacaine is the preferred anesthetic, because it is thought to be less lipophilic than bupivacaine and, as such, less cardiotoxic and neurotoxic. Minimizing the risk of local anesthetic toxicity is particularly relevant to fascial plane blocks, which remain far from the neurovascular bundle and thus require higher volumes of local anesthetic. This higher volume allows for bathing of the nerve via anesthetic tracking along the fascial plane. Table 1 above illustrates the pharmacokinetics and weight-based dosing maximums for the various local anesthetics.
Table 2 provides guidance on the fascia iliaca block volumes with the medication diluted in 0.9% normal saline to increase the volume. The suggested volumes of local anesthetic and saline depend on the type and concentration of local anesthetic also well as the patient’s ideal body weight, which impacts both the relative size of the potential space in the fascial plane as well as the maximum safe dose.
Table 2. Suggested Fascia Iliaca Block Total Volumes with Local Anesthetic + 0.9% Normal Saline [1, 3, 4]
1. Consult with orthopedist to discuss appropriateness of block.
2. Perform and document a neurovascular and compartment exam prior to and after block.
Anterior thigh (femoral)
Medial shin/calf (saphenous/femoral)
Lateral foot (sural)
Plantar surface of foot/heel (tibial)
Dorsal surface of foot (superficial peroneal)
1st webspace (deep peroneal)
Great toe extension (extensor hallucis longus)
Great toe flexion (flexor hallucis longus)
Foot dorsiflexion (tibialis anterior)
Foot plantar flexion (gastrocnemius/soleus)
3. Ensure informed consent with patient and family.
In addition to discussion of risks/benefits/alternatives, consider the relative need for pre-traction/pre-op pain control vs. post-op pain control. Depending on the dose of local anesthetic and timing of operation, a subsequent intra-operative block may or may not be possible.
4. Position the patient supine with hip and knee in extension.
5. Anticipate the child’s anxiety during the procedure.
Pro-tip: Depending on the age of the child, the presence of a guardian can be helpful in keeping the child calm and cooperative while undergoing the procedure.
It may be helpful to have a dedicated person to hold the limb of interest during the procedure.
Involve a childlife specialist, if available.
Offering the child a toy, book, or phone/tablet for distraction during the procedure can also help ease anxiety.
Intranasal or intravenous midazolam may be needed for anxiolysis.
6. Select a linear high frequency ultrasound transducer with a wide footprint.
Figure 4. Ultrasound linear transducer with wide footprint and appropriate ultrasound musculoskeletal setting
7. Apply a single-use probe cover.
Consider a Tegaderm dressing, sterile glove, condom, or sterile probe cover.
11. Perform ultrasound survey scan and identify the anatomical landmarks (Figure 7)
Muscles: Iliopsoas, sartorius
Neurovascular bundle: Femoral nerve, artery, and vein (most medial)
Fascia: Fascia lata and fascia iliaca
Figure 7. POCUS image of left hip demonstrating the normal anatomy of the femoral artery (FA), femoral vein (FV), fascia iliaca, fascia lata, femoral nerve, and iliopsoas muscle (left is medial and right is lateral)
12. Anesthetize your needle insertion point (adjacent to the lateral edge of the ultrasound probe).
Use with 1% buffered lidocaine, if available.
Alternatively, apply topical lidocaine, such as LMX or EMLA on the desired area at least 30 minutes prior to the start of the procedure.
13. Prime the needle and tubing with normal saline.
The normal saline in the tubing and needle will hydro-dissect the fascial planes prior to injecting the local anesthetic. This helps mitigate the risk for potential local anesthetic toxicity. Furthermore, it ensures appropriate fascial spread prior to injection of the anesthetic, allowing for better visualization of the anatomy and a safe window for anesthetic injection.
An alternative practice is to prime the needle and tubing with the diluted local anesthetic.
14. Insert the block/spinal needle.
Visualize the length of the needle in-plane and the needle tip at all times.
Warning: The needle shaft can easily be confused for the needle tip if the probe is not adequately oriented in parallel with the needle along the entire length. Make subtle rotations in the probe to ensure that the true needle tip is visualized.
15. Identify the femoral nerve.
Be sure to remain lateral the the femoral nerve (~2 cm). It is NOT necessary to be directly adjacent to the nerve, which increases the risk of nerve injury.
Use the ‘fanning’ technique to elicit anisotropy and identify the femoral nerve. The nerve is DEEP the fascial plane and lateral to the femoral artery. A common mistake is to misidentify the adipose tissue, which lies SUPERFICIAL to the fascial plane and is immediately lateral to the femoral artery, as the femoral nerve (Figure 8).
Figure 8. POCUS image of the left hip during a fascia iliac block procedure. The adipose tissue (pink) can be confused for the femoral nerve (yellow) which lies below the fascia iliaca (red). The local anesthetic (hypoechoic) is hydrodissecting between the vascular bundle and femoral nerve. FA=femoral artery.
16. Puncture the needle through the fascia iliaca.
Keep your neurovascular bundle in the corner of your screen as you advance your needle in order to visualize your saline and local anesthetic as you hydro-dissect the nerve from the fascia.
Be aware of the patient’s comfort throughout the procedure.
17. Practice key safe injection techniques.
Ensure excellent, real-time needle and needle tip visualization on ultrasound.
Aspirate and look for blood once the needle is below the fascia iliaca to confirm that you will not inject into the vasculature.
Hydrodissect the fascial plane with 2-5 mL of normal saline. You will visualize the saline migrating medially towards the neurovascular bundle. Make adjustments in depth to find the correct plane.
Inject small aliquots (2-5 mL at a time) of local anesthetic. Aspirate between each aliquot to check for blood, allowing time (circulation cycle) between aliquots to monitor the patient for signs of local anesthetic systemic toxicity.
Video 1. POCUS clip of a traditional femoral nerve block block showing hydrodissection. The needle is seen directly below the bright fascia iliaca with anechoic (black) saline injected into the fascial plane. Note that in this clip, the needle tip is directly adjacent to the nerve as in a traditional femoral nerve block, rather than more laterally as in a fascia iliaca block.
Video 2. POCUS clip showing a fascia iliaca block hydrodissection. In comparison to Video 1, this clip shows the needle directly below the bright fascia iliaca with anechoic (black) saline infected into the fascial plane. Note the difference in the needle positioning in comparison to the nerve. This is the correct positioning of your needle, more lateral to the neurovascular bundle compared to the needle positioning in video 1. Video courtesy of Dr. Arun Nagdev (highlandultrasound.com)
Video 3. POCUS clip showing a fascia iliaca block hydrodissection. The pulsatile femoral artery can be seen medially, and the femoral nerve can be seen being displaced downwards below the fascial plane.
18. Instill the appropriate volume of long-acting anesthetic.
Once the needle is appropriately positioned deep to the fascia iliaca plane, carefully and incrementally instill the weight-based volume of either ropivacaine or bupivacaine, utilizing the safe injection techniques described in step 17.
19. Label your block and document in the medical record.
Label the block location with a Tegaderm dressing noting time and date of procedure.
Document the procedure in real-time, including type and dose of local anesthetic, to ensure accurate and timely communication with multidisciplinary care team (e.g., anesthesia, in order to avoid cumulative local anesthetic overdose).
20. Monitor the patient post-procedure.
Maintain the patient on a cardiac monitor to watch for local anesthetic systemic toxicity for 30 minutes post-block.
Re-evaluate the patient for efficacy of the block.
There are many errors that can make defining the relevant sono-anatomy difficult, but there are 2 common errors that are easily corrected by small changes in probe placement.
1. Error: Probe placement distal to femoral artery bifurcation
Problem: In order to get the view needed for a successful block, the operator must image the vasculature at the level of the common femoral artery, prior to its bifurcation. When distal to the common femoral artery, the structures that are seen are usually the superficial and deep femoral arteries (Figure 9 and Video 4). At this level, the femoral nerve and the fascia iliaca can be difficult to visualize.
Solution: Slide the probe cephalad and position it just inferior to the inguinal ligament. The common femoral artery is well-visualized at this level.
Figure 9. Arterial anatomy of the thigh, adapted from Wikimedia Commons (left); POCUS image of the femoral artery bifurcation. which is too distal for fascia iliaca block (right)
Video 4. POCUS clip showing a femoral artery bifurcation, which is too distal for the fascia iliaca block
2. Error: Incorrect probe angle
Problem: If the probe is not perpendicular to the common femoral artery, the artery will be visualized, but the fascia iliaca and iliopsoas muscle can be difficult to locate.
Solution: Keep the probe parallel to the inguinal ligament, which aligns it perpendicularly to the common femoral artery (Figure 10).
Figure 10. Proper ultrasound probe positioning means placing the probe parallel to the inguinal canal and perpendicular to common femoral artery. Grey: probe with probe marker to patients right, Purple: inguinal canal, Red: femoral artery (illustration by Dr. Muki Kangwa)
Quadriceps muscle spasms: These are usually secondary to anesthetic injection directly into the femoral nerve.
Delayed recognition of compartment syndrome: This is less common in the thigh compartment compared to the lower leg.
Fractures account for approximately 75% of cases of acute extremity compartment syndrome. The risk increases with increasing severity of the fracture (e.g., comminuted fractures). The tibia is involved most often, with acute compartment syndrome developing in approximately 1-10% of such fractures.
Local anesthetic systemic toxicity (LAST) is a rare event resulting from dose-dependent blockade of the sodium channels in the cardiovascular and central nervous system.
Risk of LAST can be mitigated by:
Calculating the maximum safe dose for the anesthetic and patient’s weight
Real-time cardiac monitoring
Continuous needle visualization to ensure proper placement of anesthetic
Aspirating prior to each injection
Hydrodissection of fascial plane with saline prior to anesthetic
Injection of small aliquots and monitoring for signs/symptoms during circulation cycle
Nerve blockade is being performed widely by many emergency medicine physicians, and is now becoming standard of care in an attempt to reduce the amount of opiates used particularly in the elderly with femoral fractures. However, ultrasound guided nerve blockade it is not a core skill found in most pediatric emergency medicine curricula, and the lack of educational training presents a barrier to implementation within Pediatric Emergency Medicine. Prior studies of fascia iliaca nerve blockade have shown great success and improved pain control. A few of these studies are summarized below.
Wathen JE et al.
Randomized Controlled Trial Comparing a Fascia Iliaca Compartment Nerve Block to a Traditional Systemic Analgesic for Femur Fractures in a Pediatric Emergency Department (PMID 17210208)
Randomized controlled trial
Fascia iliaca compartment block performed by pediatric emergency medicine attendings and fellows for children ages 15 months to 18 years with a femur fracture can result in lower pain scores, longer duration of analgesia, and higher staff satisfaction in comparison with traditional analgesia.
Frenkel O et al.
Ultrasound-guided Femoral Nerve Block for Pain Control in an Infant with a Femur Fracture due to Non-accidental Trauma (PMID 22307191)
Case report of a 3-month-old female with a subtrochanteric femoral neck fracture due to non-accidental trauma requiring multiple doses of IV pain medication. An ultrasound-guided femoral nerve block was performed using 2 mL of 0.25% bupivacaine for placement into a Pavlik harness. The patient only required 1 dose of analgesia in 18 hours following the femoral nerve block.
Turner AL et al.
Impact of Ultrasound-guided Femoral Nerve Blocks in the Pediatric Emergency Department (PMID 24651214)
Retrospective cohort study
In a pre- and post-implementation retrospective cohort study of children with femur fractures in a pediatric ED, an ultrasound-guided femoral nerve block was associated with a 3-times longer duration of initial analgesia (6 hr vs 2 hr), lower total morphine dose, and fewer nursing interventions in comparison with systemic analgesia alone.
Neubrand T et al.
Fascia Iliaca Compartment Nerve Block Versus Systemic Pain Control for Acute Femur Fractures in the Pediatric Emergency Department (PMID 24977991)
Retrospective chart study
Retrospective chart review of children receiving systemic analgesia (control) vs fascia iliaca nerve block evaluating effectiveness and adverse effects. Outcomes included total doses of systemic medications received and comparison of pre- and post-intervention pain scores. Effectiveness, as measured by pain scores and total doses of systemic analgesia, was improved in the fascia iliaca nerve block group versus the control. There was no difference in adverse events between the groups.
Heffler MA et al.
Ultrasound-Guided Regional Anesthesia of the Femoral Nerve in the Pediatric Emergency Department (PMID 35245015)
Multicenter retrospective case series
Ultrasound-guided regional anesthesia of the femoral nerve (fascia iliaca compartment block, n=70; femoral nerve block, n=15) was performed by residents, fellows, and attendings with varying degrees of formal POCUS training for pediatric patients aged 50 days to 15 years at 6 pediatric emergency departments across North America. There were no reported complications across a heterogenous patient population at these 6 tertiary care centers, supporting the safety and generalizability of these techniques.
Table 4. Published studies supporting effectiveness of POCUS fascia iliaca nerve block in pediatric patients.
Full Video of Fascia Iliaca Nerve Block
Video 5. POCUS clip of the complete fascia iliaca block procedure. The clip starts with an initial anatomy scan, followed by needle visualization, and lastly hydrodissection.
Given that the patient remains in significant painful distress despite non-opioid analgesia, you decide to incorporate POCUS-FINB to your evaluation and treatment.
The patient is evaluated by the on-call orthopedic team member and is found to have no evidence of neurovascular compromise or signs and symptoms of compartment syndrome. You confirm the availability of lipid emulsion (intralipid) in the emergency department and calculate the maximum safe dose of your anesthetic.
The patient weighs 20 kg.
The MAXIMUM safe dose of 0.2% ropivacaine (3 mg/kg) equals 60 mg, or 30 mL.
Looking at your institutional guidelines and Table 2 you decide to use 12 mL, which is well underneath this maximum dose.
You add 3 mL of saline to increase the overall fluid volume to reach the weight-based target goal of 15 mL volume for the fascia iliaca procedure.
Tables 1 and 2 (cropped from original tables): Local anesthetic medications and their pharmacokinetics, weight-based maximum doses, and suggested total volumes (anesthetic + 0.9% normal saline) for fascia iliaca block
The patient undergoes a safe and effective fascia iliaca nerve block with her pain score improving from a 10 to a 2. The orthopedic team is able to place the patient into traction prior to transfer to the operating room.
Orthopedic Clinic Follow-Up
At her orthopedic follow-up visit 4 weeks later, she’s doing well with minimal pain. Her follow up x-ray demonstrates appropriate healing with new bone formation.
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Gadsen J. Local Anesthetics: Clinical Pharmacology and Rational Selection. The New York School of Regional Anesthesia website, October 2013.
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Black KJ, Bevan CA, Murphy NG, et al. Nerve blocks for initial pain management of femoral fractures in children. Cochrane Database Syst Rev. 2013(12):CD009587.
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Coté, Charles J., et al. “Chapter 42: Regional Anesthesia.” A Practice of Anesthesia for Infants and Children, Elsevier, Philadelphia, PA, 2019.
Frenkel O, Mansour K, Fischer JW. Ultrasound-guided femoral nerve block for pain control in an infant with a femur fracture due to nonaccidental trauma. Pediatr Emerg Care. 2012 Feb;28(2):183-4. PMID 22307191
Heffler MA, Brant JA, Singh A, et al. Ultrasound-Guided Regional Anesthesia of the Femoral Nerve in the Pediatric Emergency Department [published online ahead of print, 2022 Jan 10]. Pediatr Emerg Care. PMID 35245015
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Marin JR, Lewiss RE, American Academy of Pediatrics CoPEM, et al. Point-of-care ultrasonography by pediatric emergency physicians. Policy statement. Ann Emerg Med. 2015;65(4):472-478. PMID 25805037
Neubrand TL, Roswell K, Deakyne S, Kocher K, Wathen J. Fascia iliaca compartment nerve block versus systemic pain control for acute femur fractures in the pediatric emergency department. Pediatr Emerg Care. 2014 Jul;30(7):469-73. PMID 24977991
Turner AL, Stevenson MD, Cross KP. Impact of ultrasound-guided femoral nerve blocks in the pediatric emergency department. Pediatr Emerg Care 2014 Apr;30(4):227-9. PMID 24651214
Vieira RL, Hsu D, Nagler J, et al. Pediatric emergency medicine fellow training in ultrasound: consensus educational guidelines. Acad Emerg Med. 2013;20(3):300-6. PMID 23517263
Wathen JE, Gao D, Merritt G, et al. A randomized controlled trial comparing a fascia iliaca compartment nerve block to a traditional systemic analgesic for femur fractures in a pediatric emergency department. Ann Emerg Med. 2007. ;50(2):162-171.e1. PMID 17210208