- The greatest immediate risk of nerve blocks
is systemic toxicity from inadvertent intravascular injection. Delayed
toxicity can follow the initial injection when rapid or excessive
amounts of local anesthetics are absorbed systemically.
- Good surgical anesthesia is obtained only when
local anesthetic is injected in close proximity to the nerve or
nerves that are to be blocked.
- A perineural injection may produce a brief accentuation
of the paresthesia, whereas an intraneural injection produces an
intense, searing pain that serves as a warning to immediately terminate
the injection and reposition the needle.
- Surgical anesthesia of the upper extremity and
shoulder can be obtained following neural blockade of the brachial
plexus (C5–T1) or its terminal branches at several sites.
- The interscalene approach is most optimal for
procedures on the shoulder, arm, and forearm. Injection at the interscalene
level tends to produce a block that is most intense at the C5–C7
dermatomes and least intense in the C8–T1 dermatomes.
- The axillary approach to the brachial plexus
is most optimal for procedures from the elbow to the hand. This
approach tends to produce the most intense block in the distribution
of C7–T1 (ulnar nerve).
- Infraclavicular blocks provide good homogeneous
anesthesia to the brachial plexus and can be used for procedures
involving the hand, forearm, elbow, and upper arm and are quite
conducive for placement of an indwelling catheter for postoperative
- Intravenous regional anesthesia, also called
a Bier block, can provide intense surgical anesthesia for short
surgical procedures (< 45–60 min) on the forearm, hand,
and even the leg.
- A femoral nerve block is very useful in numerous
procedures involving the thigh and knee, such as skin grafting,
knee arthroscopy, and patellar surgery, or as an adjunct to procedures
distal to the knee that require anesthesia to the medial aspect
of the lower leg (saphenous distribution).
- There has been a recent surge of interest in
fascia iliaca blocks. Because it does not require a nerve stimulator,
it can be performed very quickly, it is not very stimulating, and
patients often do not require sedation. It is useful in procedures
involving the hip, thigh, and knee.
- Blockade of the sciatic nerve is useful for
many surgical procedures involving the hip, knee, or distal lower
extremity. The nerve can be successfully blocked at numerous sites
along its course.
- A popliteal nerve block is very useful for foot
and ankle surgery and can result in complete anesthesia of the limb
distal to the knee if a separate saphenous nerve block (terminal
nerve of the femoral nerve) is also included.
- Paravertebral nerve blocks are being increasingly
used as an effective technique for postoperative analgesia following
mastectomy, inguinal hernia repair, and several procedures involving
the chest and body wall.
Advancement in needle delivery devices, safer local anesthetics,
and development of indwelling catheters for postoperative perineural
infusion have led to a transformation in regional anesthesia; the
focus has shifted from providing intraoperative regional anesthesia
to providing intraoperative anesthesia and postoperative regional
Fundamental to the success of regional anesthesia is the ...