operation. In five patients proximal stumps ofruptured. CS roots showed .... Orthopaedic. Surgeon,. Royal. Berkshire. Hospital,. London. Road,. Reading,.
THE
ROLE
NERVE
OF
SOMATOSENSORY
CONDUCTION
STUDIES
OF
From
The
IN
BRACHIAL
LAND!,
A.
EVOKED
S. A.
institute
THE
SURGICAL
PLEXUS
COPELAND,
C.
of Orthopaedics,
Royal
B.
POTENTIALS
AND
MANAGEMENT
INJURIES
WYNN
PARRY,
National
S. J. JONES
Orthopaedic
Hospital,
London
In 15 patients who underwent open exploration of the brachial plexus, the somatosensory evoked potentials and nerve action potentials recorded at the time of operation were useful as guides to the most appropriate surgical procedure, and also in predicting the outcome in certain lesions. In three patients the apparent normality of the upper trunk of the plexus was concealing a more proximal lesion which was irrecoverable. The presence of a somatosensory evoked potential showed functional continuity in three patients in whom the C7 root was clinically involved and who recovered after operation. In five patients proximal stumps ofruptured CS roots showed functional central continuity; this indicated their sultabifity for grafting. These patients recovered except one who suffered from co-existing disease. The electrophysiological studies also confirmed the clinical diagnosis of avulsion of the CS and Ti roots and therefore
prevented
unnecessary
plexus
Surgical repair of traction produces poor results.
success lesion.
may be partly due Surgical investigation
be misleading since plexus is analysed
dissection.
lesions However,
only the apparent unless extensive
continuity laminectomy
There may also be a more the limb, which can only exploration. Electrophysiological
delineate
the
damage
(Bonney and Gilliatt 1970; Zv#{232}tina and
in
past,
very
electrophysiological plexus recordings potentials using distal
sory
over
direct point evoked
before
Zalis, Oester 1977; Jones
little
attention during
We have intra-operative the
distal co-existing be revealed by tests help operation
scalp
nerve
stumps
amenable
has
been
operations
nerve
the
action
to the
brachial
plexus
at the
Royal
National
Donal
Brooks. and
use of evoked potentials
nerve stimulation and recording at a moreS over the nerve. Recordings of somatosenpotentials at operation confirm that the
one
The
deltopectoral haemostasis,
with
conduction
Nerve the operation
Mr
of the 1 4 and
1 8 patients
recordings
remaining (average
were axis
and over
and
using
bipolar
25
were
caused
by
1 5 patients
who
months)
after
eight
displayed potential
recorded
using
distally.
the
Care
by direct Medelec
placed
parietal
lobe The
kilohertz
during electrode.
at 90 degrees response.
(Medelec
stimulation
chloride
disc
on and
the
to The
56).
by direct
evoked
to
studies.
stimulation
a monopolar
a silver-silver
1.6
taken
interference
stimulating
electrode
was obtained
to
was
to avoid
and
to the line
electrophysiological
made
(R).
incision
of the medial
on an oscilloscope
nasion
hertz
S-shaped
the clavicle
coagulation
to obtain
contralateral 32.0
then
a similar (R2)
were
the
along
a standard
with
an junction
laterally
during
evoked the
making to the
were
nerve
above
from
groove
made
potentials
somatosensory
then
1) using
of the
by
process
potentials
(Fig.
Recordings
amplified
explored
mastoid
volume
action
centimetres
the
between
of these
intra-operative for
clinic of
care
exploration
aged
Three
injuries
injuries the
for
1 7 patients
1 7 months
of the clavicle,
maintain
placed
under
considered
girl.
with
nerve
Hospital
on
results
was
of
root
peripheral
in the
were
2 and
the
thirds
the
seen
reviewed.
middle
action
120 patients
out
The
plexus
the
METHODS
1978
of incomplete
from
long
consequently
AND
Orthopaedic
between were
the
and
December
six-year-old
failure.
extending
the
were
was carried
on
because
injury,
and
Twenty-nine
which
plexus years
connected
MATERIAL
1977
January
presented
to
centrally
CLINICAL Between
technical
for brachial
investigated somatosensory and
paid
are
to grafting.
excluded
and Rodriquez 1979). These
proximal to the posterior root double lesion exists conduction a distal lesion.
tests
injuries. of
plexus
of the is
when there is a double lesion show the more distal site of conduction in an anaesthetic
area indicates a lesion ganglia. If an additional will be absent, suggesting the
the
1 958; Kredba
tests can also be misleading since all the investigations injury. Normal sensory
brachial lack of
to incorrect diagnosis of the for intraspinal lesions can
undertaken. lesion in extensive
In
of the the
The of
electrode midline
12
potential displayed
was on
A. Landi, MD, Assistente, Clinica Ortopedica, Modena, Italy. S. A. Copeland, FRCS, Consultant Orthopaedic Surgeon, Royal Berkshire Hospital, London Road, Reading, Berkshire RG1 5AN, England. C. B. Wynn Parry, MBE, Director of Rehabilitation, Royal National Orthopaedic Hospital, 234 Great Portland Street, London WiN 6AD, England. S. J. Jones, MRCP, External Staff, Medical Research Council, Institute of Neurology, Queen Square, London WC1 , England. Requests
492
for
reprints
should
be sent
to Mr
S. A.
Copeland.
THE
JOURNAL
OF BONE
AND
JOINT
SURGERY
an
ELECTROPHYSIOLOGICAL oscilloscope, using
after
after
were
up to 1 28 responses,
module
30 milliseconds roots
averaging
an averager taken
with
the
and
TESTS
256
sample
stimulus.
sent
for
at one
points
Biopsies
routine
IN
or two
spaced
of the
over
resected
histological
THE
MANAGEMENT
hertz
the first nerves
or
analysis.
RESULTS This
study
was
confined
electrophysiological operation subsequent between
and the
to the studies
correlated recovery pre-operative
electromyogram, sory evoked
implications
performed
at
the
of time
of
with the clinical findings and the patient. A comparison sensory action potential, the
of
and potentials
surgical
the intra-operative will be reported
OF
somatosensory neurofibromatosis
PLEXUS
evoked
character of somatosensory which indicated
the sural nerve evoked potential a good proximal
musculocutaneous neurotised with brachial
nerve.
Similar
re-neurotised,
anastomosed
to the
not have the time
and median nerves and
results
were
but
the
the
in grafted
median
Patient although absent.
the
found
nerve were intercosto-
with C5
nerve
which
evoked
Patient to the
nerve
been feasible of injury. The
good
suprascapular
in a good clinical recovery. A good somatosensory demonstrated stump was
patient also had the histological
used for grafting. The was present in Patient 2 stump. However, the
would from
nerve intercostal
was
493
INJURIES
potential. The which affected
length of the graft needed and 1 1 months had elapsed
who
somatosenelsewhere.
BRACHIAL
with
3 was
resulted
potential
7 and subsequently musculocutaneous
neurotised
Patient stump
was
the C5 nerve and
intercostal
grafts.
In
the
C5 root was in pseudo-continuity, the somatosensory evoked potential was Histological evidence of this root later showed 5,
that
the
somatosensory
evoked
the
not
used
in
nerve
was re-neurotised with four The absence of the somatosensory
in C8 and
absence the
Ti
of nerve
potential
predicted
operation
in the
bundles.
and
presence
correctly
This
the
stump
was
musculocutaneous intercostal evoked
of a nerve
nerves. potential
action
potential
of the median and ulnar nerves provided evidence of a preganglionic lesion and hence valuable dissection time was saved in Patients 1 and 3. An attempt was made to Cs
provide 3, where
C6
some sensation to the hand with Patients 2 and C8 and Ti were avulsed. The median nerve was
separated
Cl
into
stimulation were selected
CS
three
main
fascicles
the two fascicles and anastomosed
and
using
distal
with the largest potentials to the intercostobrachial
Ti
nerve. Group apparent group, helpful Fig. Electrode
positions
evoked
for
From
the
results
the patients fall Group I (Patients roots
group sory
(C5-T1), was the evoked
(Ri)
(5)
and
nerve
shown
and
recording
action
in Table
somatosensory
potentials
(R2).
I it can
into four main groups: 1 to 7). Lesions involved but most
be seen all the
was
useful
to determine
root was centrally connected and consequently for grafting. The C5 root was found to be grafting in Patients 1 2, 3, 6 and 7.
,
potentials later. This lesion VOL.
of the
62-B,
presence
in Patient may have
indicated
that nerve
with partial obvious avulsion. This severely affected. The somatosen-
potential
In spite
roots which would not recover spontaneously. In Patient 10, the pre-operative investigations were conflicting. The myelogram showed a meningocele at C5, and the Tinel sign was absent (Landi and Copeland 1979) but
1
stimulating
potentials
of somatosensory
1 there was no recovery been caused by a mild
by
No. 4, NOVEMBER
the
increased 1980
latency
if the
C5
suitable suitable for evoked 1 2 months intraspinal of
II (Patients 10 to 12). The upper trunk was in continuity and normal to the naked eye. In this the electrophysiological tests were extremely in demonstrating proximal lesions in the nerve
the
electromyography biceps. The
patient
showed signs of re-innervation of the was explored, and the somatosen-
sory evoked potential found to be absent for C5, C6 and C7, so the upper trunk was neurotised with the accessory nerve. Biopsies of these roots showed only scar tissue on the proximal myelinated
part. The distal fibres in the upper
biopsies trunk,
revealed but these
a few fibres
could have come from any of the surrounding tissues. This could explain why the re-innervation potentials disappeared after operation. In Patient 1 2, the upper trunk appeared normal, but the were
somatosensory absent
musculocutaneous
evoked whereas
the nerve
potential nerve were
of both
action of a high
nerve
potentials amplitude.
roots of the This
494
A.
LAND!,
S.
A.
COPELAND,
C.
B. WYNN
PARRY,
S.
J. JONES
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