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Median Nerve Block: Difference between revisions
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This page outlines the regional anaesthetic technique. For [[Carpal Tunnel Syndrome|carpal tunnel syndrome]] see [[Carpal Tunnel Injection|carpal tunnel injection]]. | |||
==Background== | ==Background== | ||
*Useful for lacerations across multiple fingers/palm instead of multiple digit blocks | *Useful for lacerations across multiple fingers/palm instead of multiple digit blocks | ||
| Line 11: | Line 15: | ||
==Contraindications== | ==Contraindications== | ||
*Infection overlying injection site | *Infection overlying injection site | ||
*Previous allergic reaction to local | *Previous allergic reaction to local anaesthesic used | ||
*Distortion of anatomic landmarks | *Distortion of anatomic landmarks | ||
==Equipment Needed== | ==Equipment Needed== | ||
*Topical | *Topical anaesthesia (LET, EMLA) | ||
*local anesthesia | *local anesthesia | ||
**[[Lidocaine]] 1% (lasts 30-60 minutes or longer if given with epinephrine, rapid onset) | **[[Lidocaine]] 1% (lasts 30-60 minutes or longer if given with epinephrine, rapid onset) | ||
**Mepivacaine 3% (lasts 45-90 minutes, slower onset) | **Mepivacaine 3% (lasts 45-90 minutes, slower onset) | ||
**Bupivacaine 0.5% (lasts 2-4 hours, slowest in onset) | **Bupivacaine 0.5% (lasts 2-4 hours, slowest in onset) | ||
*18G needle to draw up | *18G needle to draw up anaesthetic | ||
*25-30G needle to inject. Use of a larger gauge (21-23) makes it easier to see the needle on ultrasound | *25-30G needle to inject. Use of a larger gauge (21-23) makes it easier to see the needle on ultrasound | ||
*10 cc syringe | *10 cc syringe | ||
| Line 31: | Line 35: | ||
*Apply topical anesthesia if needed | *Apply topical anesthesia if needed | ||
*Draw up 5-10 mL of anesthetic into syringe | *Draw up 5-10 mL of anesthetic into syringe | ||
**Beware of toxic dose of | **Beware of toxic dose of anaesthetic you're using. | ||
*Before any nerve block, perform neurovascular exam (often includes 2 patient discrimination with paperclip) | *Before any nerve block, perform neurovascular exam (often includes 2 patient discrimination with paperclip) | ||
===Wrist Block=== | ===Wrist Block=== | ||
| Line 37: | Line 41: | ||
*Between palmaris longus and flexor carpi radialis | *Between palmaris longus and flexor carpi radialis | ||
*Insert needle perpendicular between tendons, 2-3 cm proximal to the distal crease of the wrist | *Insert needle perpendicular between tendons, 2-3 cm proximal to the distal crease of the wrist | ||
*Aspirate; if no blood inject a few mL's of | *Aspirate; if no blood inject a few mL's of anaesthetic slowly | ||
*Test sensation to pain distal to block | *Test sensation to pain distal to block | ||
===Elbow Block=== | ===Elbow Block=== | ||
| Line 43: | Line 47: | ||
*Cleanse the skin overlying the antecubital fossa with chosen antiseptic | *Cleanse the skin overlying the antecubital fossa with chosen antiseptic | ||
*Create a sterile field using sterile drape | *Create a sterile field using sterile drape | ||
*In a sterile fashion, apply a small wheel of local | *In a sterile fashion, apply a small wheel of local anaesthetic to the area immediately proximal to the antecubital fossa | ||
*Palpate the brachial artery to be aware of its path | *Palpate the brachial artery to be aware of its path | ||
**The median nerve should be approximately 1 cm medial to the brachial artery at this point | **The median nerve should be approximately 1 cm medial to the brachial artery at this point | ||
*Insert the needle approximately 1-2 cm proximal to the flexor crease and advance with negative pressure applied to the syringe | *Insert the needle approximately 1-2 cm proximal to the flexor crease and advance with negative pressure applied to the syringe | ||
*At 1-2 cm deep, aspirate prior to injection to rule out intravascular placement | *At 1-2 cm deep, aspirate prior to injection to rule out intravascular placement | ||
*Inject 5-10 mL of local | *Inject 5-10 mL of local anaesthetic | ||
===Ultrasound Guided Block=== | ===Ultrasound Guided Block=== | ||
[[File:Median | [[File:Median nerve block.mp4|thumbnail|Ultrasound-guided median nerve block<ref>http://www.thepocusatlas.com/musculoskeletal/</ref>]] | ||
*Place a linear probe on the volar aspect of the | *Place a linear probe on the volar aspect of the mid-forearm | ||
**It may be easier to find the nerve by starting with the probe over the volar wrist and sliding proximally. The tendons will disappear as they become muscles but the nerve will remain as the only continuous round structure. | **It may be easier to find the nerve by starting with the probe over the volar wrist and sliding proximally. The tendons will disappear as they become muscles but the nerve will remain as the only continuous round structure. | ||
*The median nerve takes the | *The median nerve takes the appearance of a "chocolate chip cookie" in the axial orientation and lies between the flexor digitorum profundus and supeficialis | ||
*Clean and prep the patient's arm under sterile conditions, and insert a 25 g needle in the long axis under ultrasound guidance next to the nerve | *Clean and prep the patient's arm under sterile conditions, and insert a 25 g needle in the long axis under ultrasound guidance next to the nerve | ||
*Aspirate to prevent inadvertent intravascular injection | *Aspirate to prevent inadvertent intravascular injection | ||
*Inject 5 mL of local | *Inject 5 mL of local anaesthetic so that it basks the nerve | ||
==Complications== | ==Complications== | ||
| Line 64: | Line 68: | ||
*Needle fracture | *Needle fracture | ||
*Neurapraxia | *Neurapraxia | ||
==External Links== | ==External Links== | ||
| Line 79: | Line 79: | ||
<references/> | <references/> | ||
[[Category:Elbow | [[Category:Elbow and Forearm Procedures]] | ||
[[Category:Hand | [[Category:Hand and Wrist Procedures]] | ||
Latest revision as of 21:31, 4 May 2022
This page outlines the regional anaesthetic technique. For carpal tunnel syndrome see carpal tunnel injection.
Background
- Useful for lacerations across multiple fingers/palm instead of multiple digit blocks
- Useful for exploration of flexor tendons of digits 1-3
- Ultrasound guidance significantly increases the success rate of this block [1]
Indications
- Trauma or need to perform painful procedure on area innervated by median nerve
Contraindications
- Infection overlying injection site
- Previous allergic reaction to local anaesthesic used
- Distortion of anatomic landmarks
Equipment Needed
- Topical anaesthesia (LET, EMLA)
- local anesthesia
- Lidocaine 1% (lasts 30-60 minutes or longer if given with epinephrine, rapid onset)
- Mepivacaine 3% (lasts 45-90 minutes, slower onset)
- Bupivacaine 0.5% (lasts 2-4 hours, slowest in onset)
- 18G needle to draw up anaesthetic
- 25-30G needle to inject. Use of a larger gauge (21-23) makes it easier to see the needle on ultrasound
- 10 cc syringe
- Gauze pads
- ultrasound probe cover or tegaderm to cover probe surface
Procedure
- Time out, confirm correct patient and laterality
- Apply topical anesthesia if needed
- Draw up 5-10 mL of anesthetic into syringe
- Beware of toxic dose of anaesthetic you're using.
- Before any nerve block, perform neurovascular exam (often includes 2 patient discrimination with paperclip)
Wrist Block
- Median nerve is within the carpal tunnel
- Between palmaris longus and flexor carpi radialis
- Insert needle perpendicular between tendons, 2-3 cm proximal to the distal crease of the wrist
- Aspirate; if no blood inject a few mL's of anaesthetic slowly
- Test sensation to pain distal to block
Elbow Block
- Cleanse the skin overlying the antecubital fossa with chosen antiseptic
- Create a sterile field using sterile drape
- In a sterile fashion, apply a small wheel of local anaesthetic to the area immediately proximal to the antecubital fossa
- Palpate the brachial artery to be aware of its path
- The median nerve should be approximately 1 cm medial to the brachial artery at this point
- Insert the needle approximately 1-2 cm proximal to the flexor crease and advance with negative pressure applied to the syringe
- At 1-2 cm deep, aspirate prior to injection to rule out intravascular placement
- Inject 5-10 mL of local anaesthetic
Ultrasound Guided Block
Ultrasound-guided median nerve block[2]
- Place a linear probe on the volar aspect of the mid-forearm
- It may be easier to find the nerve by starting with the probe over the volar wrist and sliding proximally. The tendons will disappear as they become muscles but the nerve will remain as the only continuous round structure.
- The median nerve takes the appearance of a "chocolate chip cookie" in the axial orientation and lies between the flexor digitorum profundus and supeficialis
- Clean and prep the patient's arm under sterile conditions, and insert a 25 g needle in the long axis under ultrasound guidance next to the nerve
- Aspirate to prevent inadvertent intravascular injection
- Inject 5 mL of local anaesthetic so that it basks the nerve
Complications
- Bleeding
- Infection
- Pain
- Needle fracture
- Neurapraxia
External Links
References
- ↑ Liebmann O, Price D, et al. [Feasibility of Forearm Ultrasonography-Guided Nerve Blocks of the Radial, Ulnar, and Median Nerves for Hand Procedures in the Emergency Department]. Ann Emerg Med 2006; 48(5):558-62.
- ↑ http://www.thepocusatlas.com/musculoskeletal/
