Page 351 Guide to Pain Management in Low-Resource Settings

Techniques for Commonly Used Nerve Blocks 339

• Have the patient’s arm raised with the hand be- Ankle block
hind the head. Indications would be all kinds of foot surgery, includ-
• Confi rm the rib by palpation or adequate land-
ing amputations. For an eff ective ankle block, proceed
marks. as follows:
• Identify the midaxillary line.
• Position the patient supine.
• To avoid pneumothorax, the needle point should • Block the superfi cial peroneal nerve with subcu-
be in close proximity to the rib.
taneous infi ltration between the anterior edge of
• Th e rib is held between the second and third fi n- the tibia and the upper edge of the lateral malleo-
gers.
lus with 5–10 mL anesthetic solution.
• Insert the needle between the second and third • Block the sural nerve by subcutaneous infi ltra-
fi nger and advance to make contact with the rib.
tion of 5 mL local anesthetic between the Achilles
• Direct the needle downward (caudally) and walk tendon and the lateral malleolus.
the needle until it slides off .
• Infi ltrate the saphenous nerve with of 5 mL of
• Advance the needle not more than 5 mm to pre- subcutaneous local anesthetic from the anterior
vent pneumothorax.
edge of the tibia to the Achilles tendon.
• Finally, inject 2–3 mL of 0.5% bupivacaine at each • Block the deep peroneal nerve by inserting the
level, after careful aspiration, as the intercostal ar-
needle between the tendon of the extensor pol-
tery and nerve are very close by. licis muscle and the dorsalis pedis artery on the
Wrist block dorsum of the foot. Th e needle is inserted per-
pendicularly to the skin and advanced slightly
Wrist blocks may be used if a plexus block is incom-
under the artery. Following negative aspiration
plete, as a diagnostic block, or for pain therapy. Be
inject 5 mL local anesthetic.
familiar with the anatomy. The median nerve is lo-
• Tibial nerve block can be obtained with the nee-
cated on the radial site of the palmaris longus tendon
dle inserted directly dorsal to the posterior tibial
(better visible when flexing the wrist), and the ulnar
artery on the medial side of the joint, or alterna-
nerve is located on its other (ulnar) side. The radial
tively, directly anterior to the Achilles tendon be-
nerve is superficially located at the lateral aspect of
hind the medial malleolus.
the wrist.
To block the median nerve:
• Insert the needle on the fl exor side between the Pearls of wisdom
tendons of the fl exor carpi radialis and palmaris
longus tendon. • Some peripheral nerve blocks are very easy to
• After eliciting paresthesias, withdraw slightly and perform and very eff ective.
inject 3–5 mL. • Th ey can be performed with minimum training.
To block the ulnar nerve: • Nevertheless, anatomical details have to be
• Have the arm stretched out and the hand supi- known and memorized (see webpage).
nated. • Peripheral nerve blocks will work better if there is
• Insert the needle approx 3–4 cm proximal to the no local infl ammation.
crease between the fl exor carpi ulnaris tendon • Toxicity of local anesthetics can be prevented (al-
and the ulnar artery. most always) by respecting maximum doses and
• After eliciting a light paresthesia, withdraw the avoiding intravascular injection with careful aspi-
needle slightly and inject 3–5 mL of the local an- ration.
esthetic. • In case of local anesthetic toxicity have all neces-
To block the radial nerve: sary instruments and drugs ready for treatment,
• Have the arm stretched out and the hand supi- otherwise refrain from performing blocks.
nated. • In case of paresthesias, withdraw the needle to
• Infi ltrate subcutaneously on the radial side of the avoid injury to the nerve.
wrist 3–5 cm proximal to the radial head point. • Do not use blocks if the patient is not willing.