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Injury to the radial nerve results in loss of
extension of the wrist, fingers and thumb. The resulting difficulty in grasping objects leads to significant disability. When
the nerve is injured to the extent that it will not recover and nerve repair or
grafting is not possible, tendon transfers can provide some return of
function. Ideally however, acute injuries resulting in nerve transection
are primarily repaired or grafted.
Radial Nerve Anatomy
The radial nerve arises from the posterior cord of
the brachial plexus and travels around the posterior aspect of the humerus in
the spiral groove with the profunda brachial artery. The nerve distributes branches here to the triceps muscle.
In severe humeral fractures, the radial
nerve is often injured at this level. The nerve travels distally where it enters
the anterior compartment of the arm as it pierces the lateral fascial septum
just proximal to the elbow. The nerve then divides in the forearm and gives off
branches to the brachialis, brachioradialis and extensor carpi radialis longus.
It often then divides into a sensory and posterior interosseus branch that
provides motor function the the rest of the dorsal forearm extensor muscles.
Clinical Example of Radial Nerve Grafting
 This
patient suffered a left arm radial nerve
injury, Sunderland Type V. The
patient had loss of function of all the
extensor tendons of the hand and wrist,
except for some ECRL tendon
function. This gave minimal wrist
extension with radial deviation.
In this photo the mobile wad of the
forearm is marked, showing the ECRL and
Brachioradialis muscles. A point
of maximal Tinel's sign is marked.
 At
operative exploration the posterior
interosseous branch of the radial nerve
is found to be transected, with a large
neuromatous stump visible against the
microsurgical background. After trimming of the nerve ends the nerve
could not be repaired primarily and required grafting.
In practice, a separate surgical exposure is used
for the proximal and distal nerve, but for visual clarity the exposure is
pictured above as a single incision. The nerve is grafting from the
proximal radial nerve posterior interosseous branch origin, under the
bracioradialis, ECRL, ECRB muscle mass and to the distal posterior interosseus
nerve. The supinator is divided completely or partially to expose the
distal nerve.
 Two cables in total were
grafted. Pictured here are the
nerve grafts in position against a
microsurgical background after suturing
with 9-0 nylon microsurgical suture
under the operating microscope.
Each line on the microsurgical
background represents 1 millimeter.
 The
patient required intensive physical
therapy and was able to regain extension
in the fingers and thumb, with
centralized wrist extension. He is
show here in extension at nine months
pos-operatively.
 The
patient is still able to make a full
fist and suffers from no loss of flexion
due to excellent hand therapy
supervision and effort. The medial
proximal scar is visible in this photo
and the one above. Both medial and
lateral approach incisions were required
to follow the nerve under the mobile
wad.
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