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I have completed bits of my EM training from India. Currently I am boarded with credentials from Christian Medical College, Vellore and also from the prestigious Royal College of Emergency Medicine, UK.  I am currently working in London as an A&E doctor, trying to appreciate the differences in the practise and culture of Emergency Medicine across different healthcare systems. I have always been an avid FOAMed supporter because FOAMed played an indispensable role during the days of my initial training. Through this blog, I aspire to disseminate knowledge and stay up to date with the EM literature. 

Monday, July 24, 2017

Femoral Nerve block and Three-in-one block

Three-in-one nerve block may be used to block the femoral, obturator, and lateral femoral cutaneous nerves with a single injection. The femoral nerve runs down the thigh in a fascial sheath that is continuous with the nerve sheath that contains all three nerves more proximally. Just like FICB, the idea is to inject a large amount of local anaesthetic that will track proximally, medially, and laterally and thereby block all three nerves and provide more complete analgesia of the femoral neck and hip joint. 

The technique for performing both a femoral and three-in-one nerve block is identical except that the three-in-one block requires a larger volume of local anesthetic (25 to 30 mL versus 20 mL). Three-in-one nerve block provides better analgesia of the femoral neck and hip joint. 



Anatomy
The femoral nerve is formed from the posterior branches of L2-L4 and is the largest branch of the lumbar plexus. The nerve emerges from the psoas muscle and descends between the psoas and iliacus muscles. It passes under the inguinal ligament in the groove formed by these muscles lateral to the femoral artery and divides into anterior and posterior branches. 

The anterior branches innervate the anterior aspect of the thigh, and the posterior branches innervate the quadriceps muscle and continue below the knee as the saphenous nerve to provide sensory innervation from the medial side of the calf to the medial malleolus.




The lateral femoral cutaneous nerve arises from the second and third lumbar nerve roots. The nerve emerges from the lateral border of the psoas muscle and travels under the iliac fascia, across the iliac muscle, and under the inguinal ligament 1 to 2 cm medial to the anterior superior iliac spine. It branches into anterior and posterior branches 7 to 10 cm below the anterior superior iliac spine. The anterior branch innervates the skin over the anterolateral aspect of the thigh to the knee, whereas the posterior branch of the nerve innervates the lateral part of the thigh from the greater trochanter to the middle of the thigh.

The obturator nerve arises from the anterior divisions of L2-L4. It descends through the fibers of the psoas muscle and emerges from its medial border near the brim of the pelvis. It then passes behind the common iliac arteries and runs along the lateral wall of the lesser pelvis, above and in front of the obturator vessels to the upper part of the obturator foramen. Here, it enters the thigh through the obturator canal and divides into an anterior and a posterior branch. The obturator nerve is responsible for sensory innervation of the skin of the medial aspect of the thigh and motor innervation of the abductor muscles of the lower extremity.



Technique
  • Arrange the equipment and take verbal/written consent
  • Place the patient in a supine position
  • Do a quick neuromuscular exam 
  • Prepare the skin overlying the femoral triangle following usual aseptic precautions 
  • Palpate the femoral artery 1 to 2 cm distal to the inguinal ligament and inject a subcutaneous wheal of local anaesthetic (1% Lignocaine) 1 to 2 cm lateral to this point. Keep the nondominant hand on the femoral artery throughout the remainder of the procedure. 


  • Insert a 22-gauge needle just lateral to the artery at a 30-60 degree angle to the skin. Slowly advance the needle cephalad until one of the following occurs: 
  1. a “pop” with sudden loss of resistance (signifying penetration into the femoral nerve sheath) is felt
  2. a paresthesia is elicited, 
  3. the needle pulsates laterally, which signifies a position adjacent to the femoral artery. Inject 25 to 30 mL of aesthetic (0.25% Bupivacaine). 
  • The block usually takes 15 minutes to take effect. If proximity to the nerve is uncertain (e.g., a pop is not appreciated, a pares- thesia is not elicited, or the needle does not move with pulsa- tion of the femoral artery), inject the anesthetic in a fanlike distribution lateral to the femoral artery in an attempt to anesthetize the nerve.

  • It is also recommended to apply finger pressure 2 to 4 cm below the injection site to help spread the local anesthetic proximally to the obturator and lateral femoral cutaneous nerves. 


How is three-in-one block/femoral N block different from FICB?

The injection site for FICB is more lateral as compared to Femoral/Three-in-one block and thus FICB is less likely to injure the vessels. Additionally, FICB is a compartment block and thus requires more volume of local anaesthetic. 


Posted by:



              
     Lakshay Chanana
     
     Speciality Doctor
     Northwick Park Hospital
     Department of Emergency Medicine
     England

     @EMDidactic



Monday, July 17, 2017

Fascia Iliaca Compartment Block (FICB)

Nerve blocks are used in Emergency Departments to decrease the need for systemic analgesia and avoid opioid/NSAID side effects especially in elderly population. One of the commonly performed block is Fascia Iliaca Block for fractured femurs. The major advantage of a FICB is that the nerve and artery can be avoided as the site of injection is much lateral to Femoral artery in contrast to Femoral Block. It is important to note that FICB is a compartment block and thus needs at least 30ml of Local Anesthetic

Let's review the anatomy of femoral nerve and then go through through the landmark technique to perform FICB.


Anatomy 

Femoral Nerve
The femoral nerve is formed from the lumbar plexus ( L2 to L4). It supplies periosteum of the femur, motor innervation to the extensors of the knee, sensory innervation to the anterior thigh, anteromedial aspect of the knee, medial lower leg and the medial aspect of the ankle and foot. 



FN emerges below the inguinal ligament lateral the femoral vein and artery. It is covered by, and separated from the vascular bundle by the fascia iliaca. Overlying fascia iliaca, there is fascia lata which runs together with the fascia iliaca laterally. The fascia iliaca compartment within the pelvic brim also contains the lateral cutaneous nerve of the thigh laterally. This nerve supplies sensory supply to the lateral thigh.

Red dot on the image above represents the site of injection. Note, it is at least 2-3cm lateral from femoral artery unlike femoral block.  



FICB

This compartment allows deposition of local anaesthetic of sufficient volumes (at least 30mls) spread to at least two of the three major nerves that supply the medial, anterior and lateral thigh with one simple injection, namely the femoral and lateral femoral cutaneous nervesObturator nerve is often not blocked despite good technique. 

Indication: Peri-operative analgesia for patients with neck of femur or femoral shaft fractures. 


Contraindication
  • Patient not co-operative or refusing
  • Allergic reaction to Local
  • Infection over the site
  • Previous femoral-bypass surgery
  • Anticoagulation – INR >1.5 (Relative)


Equipment
1 One Compartment Tray 
1 FIB Needle
1 Injection needle 25G
1 Drawing Up needle 18G 

1 Syringe 5 ml
2 Syringes 20 ml
5 Gauze swabs 

Intralipid


Technique (Landmark)
  • Place the patient supine and obtain Verbal/Written consent
  • Do a neuromuscular exam prior to the block
  • Follow Aseptic precautions
  • Draw a line between ASIS and Pubic Tubercle and divide it into 3 parts (see image below)
  • Point of injection is 1cm inferior to this line at the junction of lateral and middle 1/3  (i.e a1cm inferior to the junction of medial 2/3 and lateral 1/3)
  • Feel for femoral artery and ensure that you are at least 3-4 cm lateral to it. 
  • Anesthetise skin with 2-3 ml 1% Lidocaine 
  • Inject Bupivacaine - Advance the needle and feel for two distinct “pops” (fascia lata and then fascia iliaca). Advance the needle a further 1-2mm.
  • Aspirate, and if negative inject slowly. There should be no resistance to injection. If there is, it means you are too deep. Withdraw the needle until injection is easy. There should be no pain or paraesthesia on injection. Inject slowly, aspirating with every 5mls. 
  • Withdraw the needle at the end of the procedure and apply a little pressure to the area for up to two minutes. The idea to to ensure maximum drug is delivered proximal to the site of injection and thus reaching all the three nerves. 



Draw a line between ASIS and Pubic tubercle and inject local 1cm inferior to the junction of medial 2/3 and lateral 1/3. Inject liberally at least 30mls of 0.25% Bupivacaine.



Take Home
  • FICB is an effective way to provide pain relief and avoid side effects of systemic pain killers.
  • It is a compartment and thus adequate amount of local needs to be injected. 
  • It aims to block three nerves (Femoral, Obturator and Laternal Cutaneous). Despite a good technique, obturator is often not blocked. 


Posted by:

              
     Lakshay Chanana
     
     Speciality Doctor
     Northwick Park Hospital
     Department of Emergency Medicine
     England

     @EMDidactic