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The cervical paravertebral approach to the brachial plexus results in a
volume-dependent blockade of the roots of the brachial plexus. Cervical
paravertebral block is indicated for anesthesia and postoperative analgesia
in all major surgery on the upper extremity, including surgery on the
shoulder, elbow, and wrist.1 It is also suitable for
patients in whom it is difficult to reach the brachial plexus trunks via the
interscalene approach.2 Because both the
loss-of-resistance technique and nerve stimulation can be used for placement
of this block, it is well suited to postoperative placement or for other
patients (eg, patients with fractures of the arm) in whom motor activity due
to nerve stimulation may be poorly tolerated.1
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The technique described in this chapter is a modification of the
single-injection block, originally described by Kappis in the
1920s3 and modified by Pippa in 1990.4
The original technique never gained popularity, probably because it was
uncomfortable to patients due to penetration of the paraspinal extensor
muscles of the neck. A modified technique, which does not penetrate these
muscles, was described recently.5,6 The modification is
insertion of the needle in the V-shaped space between
the levator scapulae and trapezius muscles at the level of the sixth
cervical vertebra. By this method, penetration of the posterior paraspinal
muscles is avoided, which minimizes the associated pain of this approach.
Because all of the structures (eg, vertebral artery and vein, phrenic nerve,
carotid and other major arteries, internal jugular vein, etc.) associated
with complications from brachial plexus blockade are anterior to the nerve
roots in the neck, where they exit the neuroforamina, Kappis' original
argument that it is best to approach the roots from the posterior, where there
are only muscles, remains valid. Furthermore, at the root level of the
brachial plexus, which is the level at which this block is
done,5,6 the nerve fibers are arranged with sensory
fibers posterior and motor fibers anterior. This probably explains the
predominantly sensory block when approached from the posterior aspect of the
neck.
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The brachial plexus is situated between the anterior and middle scalene
muscles (Figure 24–1). The phrenic nerve lies in front of the
anterior scalene muscle. The vertebral artery and vein are situated anterior
to the pars intervertebralis, or articular column
of the vertebrae. The approach described in this section1,2,5,6
avoids penetrating the extensor muscles of the
neck by entering the neck through the “window” at the level of apex of the
V formed by the trapezius and levator scapulae muscles
(Figure 24–2).
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