Nerve and ring blocks

Attention

• Before starting and when finished, always check hands/feet (peripheries) for colour, warmth, sensation, movement, swelling, peripheral pulses — to make sure no damage done to nerves, arteries or veins
• 2–5mL of lidocaine (lignocaine) 1% usually enough for most procedures, except where indicated
• Check before using any more — see Giving local anaesthetic before closing a wound
• If longer duration needed (eg ongoing pain relief) — use lidocaine (lignocaine) 2% up to 3mg/kg without adrenaline (epinephrine) OR 7mg/kg with adrenaline (epinephrine)
  
• Do not repeat maximum dose until after 90 minutes
• Always pull back on (withdraw) syringe plunger before injecting to make sure needle is not in vein or artery
• If there is a lot of resistance when injecting or it is very painful — withdraw needle by 0.5cm and then inject
• Prevents damage caused by injecting straight into a nerve
• Massaging the injected area for 30 seconds can help improve anaesthesia
• Wait 3–5 minutes for local anaesthetic to work before starting procedure
• Check area for feeling with sharp needle. Also gives person confidence

Do not

• Do not use lidocaine (lignocaine) + adrenaline (epinephrine) for fingers, toes, penis, nose, ears

What you need

• Marker or pen
• Sterile dressing pack
• Chlorhexidine and Povidone-iodine solution
• Lidocaine (lignocaine) 1% or 2%
  
• 5–10mL syringe, 10mL will be needed for foot and hand blocks
• 21G needle for drawing up the solution and 25G needles for injection
• Sterile gloves
• Small sticking plaster

What you do

For all procedures

• Put clean bluey under site
• Lay out dressing pack and equipment
• Wash hands and put on sterile gloves
• Clean site and drape with sterile towels
• Put in local anaesthetic and do procedure
• Cover with sticking plaster dressing if needed
• Check peripheries (hands/feet) for colour, warmth, sensation, movement, swelling, peripheral pulses
• Warn person they will have little or no feeling in area for a few hours, may need help

Finger nerve block

There are four nerve branches in each digit (including the thumb) — 2 along dorsal (the top) and 2 along palmar (the bottom) — Figure 7.71. Toes are similar

What you do

• Inject both sides of finger — Figure 7.72, Figure 7.73
• Inject lidocaine (lignocaine) 1% – 1–2mL

Thumb nerve block

What you do

• Thumb needs only one injection site, with needle angled in 2 directions — Figure 7.74, Figure 7.75
• Inject lidocaine (lignocaine) 1% – 1–2mL

Hand — anatomy and infiltration sites

Figure 7.76 shows basic anatomy and structures you need to know to find right site for each injection

Attention

• To find palmaris longus tendon — ask person to put tip of thumb and little finger together and flex (bend) wrist forward. You will see tendon stand out in the middle of inner wrist
  
• Remember: Not everyone has this tendon
• To find flexor carpi ulnaris tendon — ask person to flex (bend) wrist forward against resistance. Tendon can be felt easily at level of wrist crease, on little finger side, just below pisiform bone (bone at base of palm)

Hand — median nerve block

What you do

• Lay person’s hand on flat sterile surface, palm up
• Find space between palmaris longus and flexor carpi radialis tendons, mark this spot with pen
• Hold syringe at 90° (right angle) to wrist and put needle between these tendons at level of ulnar and radius head and second wrist crease — Figure 7.76.  Put needle in 1cm
• Pull back on plunger to check for vein/artery
• Inject lidocaine (lignocaine) 1% — 3–5mL, leaving small amount to keep injecting as you pull out needle

Hand — ulnar nerve block — lateral approach

What you do

• Lay person’s hand on flat sterile surface, palm up
• Find site at level of wrist crease on little finger side of wrist, underneath flexor carpi ulnaris tendon — Figure 7.76. Mark with pen
• Hold syringe horizontally (on its side) toward site. Put needle in 1–1.5cm
• Pull back on plunger to check for vein/artery
• Inject lidocaine (lignocaine) 1% — 3–5mL, leaving a small amount to keep injecting as you pull out needle
• If you need to numb ulnar nerve for the back of the hand — Figure 7.76
  
• Inject lidocaine (lignocaine) 1% — 2–3mL under skin on the back of the hand on ulnar (little finger) side in line with previous injection

Hand — radial nerve block

Attention

• Do not infiltrate (inject) lidocaine (lignocaine) all the way around wrist. Stop at the middle of the upper wrist — Figure 7.77

What you do

• Lay person’s hand on flat sterile surface, palm down
• Find radial pulse at level of wrist crease, mark radial artery with pen so you can avoid it
• Draw up lidocaine (lignocaine) 1% — 5–10mL
• Put needle in 1–1.5cm, to side of radial artery (outside thumb edge, toward top of wrist) — Figure 7.77
  
• Pull back on plunger to check for vein/artery — beware of radial artery
• Inject lidocaine (lignocaine) 1% — 2–5mL
• Pull out needle

• Wait a few moments for anaesthetic to work
• Point needle across the back of the hand toward the middle of the wrist
• Put needle in just under the skin (superficially) at about the mid-point of the wrist and still in line with wrist crease
• Inject lidocaine (lignocaine) 1% — 2–5mL
• Pull out needle
• May need 2 injections to reach mid-point of wrist depending on size of wrist — you are trying to create a continuous line of LA spreading up toward the mid-wrist
• Do not inject any further than the mid-wrist

Toe nerve block

What you do

• Use same technique as for finger nerve block

OR

• Toes other than big one can be anaesthetised using one injection site because they are small and narrow
• Put needle in at entry site. Don’t take needle right out when moving it from one side to the other — Figure 7.78 (see also Figure 7.74, Figure 7.75)

Foot nerve block

• 5 major nerves in foot
• Sural and posterior tibial nerve blocks most useful for procedures on sides and sole of foot

Foot — sural block

• Will anaesthetise outside (lateral side) of foot and heel — Figure 7.79. Injection is on the outside of ankle (lateral)

What you do

• Put needle in 1cm, behind lateral malleolus (outside ankle bone) to the side of and anterior (in front) of the achilles tendon — Figure 7.80
• Pull back on plunger to check for vein/artery
• Inject lidocaine (lignocaine) 1% — 3–5mL. Use fan-like pattern in shaded area — Figure 7.80

Foot — tibial (posterior) block

• Position the patient supine either lying on their back or sitting with legs extended
• Will anaesthetise sole of foot — Figure 7.81. Injection is on medial (inside of) ankle

Attention

Beware of tibial artery

What you do

• Face person
• Feel for tibial artery just behind medial malleolus (inside ankle bone)
• Tibial nerve lies just behind artery. Mark spot with pen — Figure 7.82
• Put needle in 1cm deep, in line with the inside medial malleolus (ankle bone)
• Try to inject close to but not into the tibial artery
• Do not go too deep or you may inject into nerve
• Pull back on plunger to check for vein/artery. Beware of tibial artery
• Inject lidocaine (lignocaine) 1% — 2–5mL