Introduction
Neurovascular injury in the shoulder region following blunt trauma that is not associated
with either anterior dislocation of the shoulder or fracture of the humeral neck has
been rarely reported [[1],[2],[3],[4],[5],[6]]. Furthermore, revision of the literature showed that there are only a few case
reports of delayed onset of brachial plexus palsy due to hematoma or pseudoaneurysm
formation following trauma in the shoulder region [[7],[8],[9]]. However, in these reports, this condition only affected old patients who had sclerotic,
non-elastic vessels. Here, we report a young patient who suffered axillary artery
injury combined with delayed brachial plexus palsy that occurred tardily due to compressive
hematoma after blunt trauma to the shoulder. The patient was successfully treated
using surgical intervention.
Case presentation
A 16-year-old male who injured his right shoulder in a motorbike accident presented
himself to a regional general hospital on the same day of the injury. On initial physical
examination, he complained of tenderness of the shoulder and axillary regions. Roentgenograms
revealed a non-displaced fracture at the distal end of the right clavicle but neither
dislocation of the glenohumeral joint nor humeral neck fracture was observed ([Figure 1]). Blood supply to the right arm was intact, and the pulses of the radial and ulnar
arteries in the affected right arm were palpable. Blood pressure difference between
the right and left upper arms was not evaluated at that point. Neurological examination
revealed sensory deficit on the lateral aspect of the right upper arm. Although the
patient could elevate the upper arm more than 90° against gravity, muscle contraction
of the deltoid muscle was not seen under voluntary elevation of the upper arm. There
was no other sensory or muscle power deficit. At that point, axillary nerve palsy
was diagnosed, and an electrophysiological examination was scheduled for the detailed
evaluation of other nerves. However, on the third day after the accident, the patient
developed swelling and tenderness in his right upper arm and shoulder, and became
paralyzed in his right arm. He was referred to our department. On physical examination,
the pulses of the radial and ulnar arteries of the right arm were significantly diminished
compared to those in the left arm. Blood pressure was 42/20 mm Hg (systolic/diastolic)
in the right arm, and 122/70 mm Hg in the left arm. Widespread ecchymoses were observed
on the medial aspect of the upper arm. On neurological examination, muscle power in
the right arm included brachialis (M0), biceps (M0), triceps (M0), pectoralis major
(M3), pronator teres (M3), supinator (M1), flexor carpi radialis (M3), flexor carpi
ulnaris (M3), extensor carpi radialis longus/brevis (M2), flexor digitorum profundus/sublimis
(M4), flexor policis longus (M4), extensor digitorum communis (M0), extensor policis
longus (M0), and intrinsic muscles (M2) according to the classical medical research
council scale. Muscle power of the deltoid and supra/infra spinatus muscles could
not be evaluated exactly due to shoulder pain from the fractured clavicle. However,
the patient could elevate the upper arm 120° against gravity, indicating that the
suprascapular nerve was intact. Complete sensory loss was observed in the lateral
aspect of the upper arm and dorsoradial aspects of the forearm and hand, and the volar
aspects of the forearm and hand were slightly numbed. The patient complained of slight
dull pain (neurostenalgia) at the radial aspect of the forearm. Selective digital
subtraction angiography of the axillary artery through the right femoral artery showed
complete occlusion of the axillary artery at the site of the coracoid process of the
scapula ([Figure 2]). Collateral blood circulation to the forearm was preserved through the thoracoacromial
and posterior circumflex humeral arteries. Magnetic resonance imaging (MRI) demonstrated
a mass measuring 4 × 5 cm that was suspected to be a hematoma compressing the axillary
artery and brachial plexus in a space between the subscapular muscle and the pectoralis
minor muscle ([Figure 3A] and [3B]). On the same day of referral, surgical explorations of the axillary artery and
brachial plexus, and evacuation of the hematoma were performed under general anesthesia.
At intraoperative observations, the axillary artery was found to be occluded with
thrombus along 5 cm, at the site where the pectoralis minor muscle overlaid the artery;
however, the adventitia of the artery was not ruptured. A subscapular artery was ruptured
at the site of origin from the axillary artery; the brachial plexus was compressed
by the hematoma along a dorsal direction. Following evacuation of the hematoma, the
infraclavicular part of the brachial plexus was explored from the origin of the cords
to the terminal branches. Macroscopically, the brachial plexus was intact. Intraoperative
electrostimulation on the terminal branches of the infraclavicular brachial plexus
was performed. Although stimulation of the nerves other than the axillary nerve induced
the contraction of the innervated muscles, deltoid muscle contraction didn’t occur
after the stimulation of the axillary nerve. After exploration of the axillary nerve,
it appeared continuous, but tension was slackened. External neurolysis of the nerve
was performed to promote spontaneous recovery. The axillary artery was transected
to observe the interluminal conditions. The artery was occluded by thrombus; the intima
was damaged. The intraluminal thrombus was removed using a 4 French Fogarty catheter
in both proximal and distal directions, and revascularization was established by performing
an interpositional great saphenous vein graft. The proximal and distal sites of the
graft were anastomosed using side-to-end and end-to-end methods, respectively. Care
was taken not to sacrifice collateral blood circulation ([Figures 4A] and [4B]). The ruptured subscapular artery was not repaired but ligated because the artery
was stretched and damaged. Heparin and regional thrombolytic therapy with urokinase
were administered intravenously to the patient for 5 days after surgery as an anticoagulatory
treatment. Just after the surgery, both the radial and ulnar arteries of the right
arm became pulsatile, as in the left arm. The sensorimotor functions started to recover
from the first day after surgery. All nervous functions except for that of the axillary
nerve were sufficiently recovered within 3 days. One year after surgery, muscular
powers except for that of the deltoid muscle were completely recovered. Despite of
the atrophy of the deltoid muscle, muscle contraction was seen under voluntary elevation
of the upper arm against gravity. The patient could abduct his shoulder 180° with
a 10-kg load by conjoint function with the supra spinatus muscle. Electromyographic
examination of the deltoid muscle revealed motor units under voluntary control, mild
decrease in interference patterns and re-innervations, confirming the partial recovery
of muscle function. Sensory disturbance on the lateral aspect of the right upper arm
also recovered to normal sensation. The patient was satisfied with the function of
his right arm ([Figures 5A] and [5B]).
Figure 1
Roentgenogram at the time of injury. A non-displaced fracture (white arrow) at the distal end of the right clavicle was
observed.
Figure 2
Selective digital subtraction angiography of the axillary artery. The axillary artery was completely occluded at the site of the coracoid process
of the scapula, and collateral flow through the thoracoacromial (*) and the posterior
circumflex humeral (†) arteries existed.
Figure 3
T1-weighted magnetic resonance imaging scan. A large mass (white arrowheads) that was suspected to be a hematoma was present,
compressing the brachial plexus in a space between the subscapular and pectoralis
minor muscles.
Figure 4
Intraoperative image of revascularized site. A: Photograph, B: Scheme. Revascularization of the injured axillary artery was achieved
using an interpositional great saphenous vein graft. The proximal and distal sites
of the graft were anastomosed using side-to-end and end-to-end methods, respectively.
AA: Axillary artery, PA: Proximal anastomosis, GSVG: Great saphenous vein graft, DA:
Distal anastomosis, BA Brachial artery.
Figure 5
Analysis of the function of the affected upper arm one year after surgery. A: Atrophy of the deltoid muscle was observed. B: The patient could abduct his shoulder,
and did not have any significant inconvenience with his right arm, in his daily life.
Discussion
Cases of delayed brachial plexus palsy due to a hematoma from a ruptured subscapular
artery without association of either shoulder dislocations or humeral neck fractures
have been previously reported [[1],[6]]. In previous reports, the affected patients were elderly people with non-elastic
vessels, and the etiology was advanced arteriosclerosis that can be vulnerable to
stretching force in shoulder trauma. However, our present case was only 16 years old.
Injuries of the axillary artery and/or its branches can affect young patients who
have suffered blunt injuries in the shoulder region even if fractures and/or joint
dislocation were not associated.
Axillary artery injury might be accompanied with brachial plexus injury with an incidence
rate of 27–44% [[10]]. The usual mechanisms of brachial plexus injuries involve direct impact or forceful
stretch with extreme movement of the neck and/or arm; and symptoms usually occur just
after the injury. In the present case, nervous deficits except for those from the
axillary nerve injury occurred tardily from the third day after the initial injury.
We postulated that the mechanism of nerve injuries in the present case occurred as
follows. A hematoma from the ruptured subscapular artery formed, and nerve compression
by the hematoma and/or swollen soft tissues promoted nerve palsy. The development
of the hematoma was suspected to have led to gradual progressive brachial palsy. Ischemia
of the nerves due to axillary artery occlusion might play a subsidiary role in causing
brachial palsy. This possible cause of neuropathy after shoulder injury has been reported
by Stenning et al. [[11]]. The intraoperative findings showed that the hematoma was located dorsally to the
cords of the brachial plexus; the cords were compressed by the hematoma against the
swollen pectralis minor muscle. In the present case, nervous disturbance was more
significant in the muscles and sensory territory that were innervated by the posterior
cord than the lateral or medial cords. These findings could be supported by the fact
that the posterior cord was most closely located to the hematoma; and the posterior
cord could be directly compressed by the hematoma. Additionally, in the triangular
space formed by the subscapularis muscle, pectoralis minor muscle, and thorax where
the cords are located, the medial part of this space had more space than on the lateral
part. This might explain the fact that the muscle and sensory territories that were
innervated by the medial cord were the least impaired.
According to the critical analysis and intraoperative findings of the present case,
the etiology of axillary nerve palsy was more likely the direct stretching of the
nerve at the time of injury rather than compression by a posttraumatic hematoma. Hyperabduction
of the glenohumeral joint resulted in stretch injury of the axillary nerve. Intraoperative
findings of the loosened but continuous axillary nerve supported this speculation.
The severity of the injury of the axillary nerve was categorized as Sunderland’s grade
3, in which axon continuity is disrupted by the loss of endoneural tubes but the perineurium
is preserved. We performed external neurolysis only to promote spontaneous recovery.
Reported prognosis and management programs for axillary nerve palsy have been inconsistent.
Although Sunderland [[12]] stated that most cases of axillary nerve palsy recover spontaneously, Berry et
al. [[13]] described that axillary nerve palsy following blunt trauma without an associated
fracture or dislocation tend to result in poor recovery. In their report, only 2 of
8 patients with initial complete axillary nerve palsy following blunt trauma without
associated fracture or dislocation recovered well. In the present patient, however,
without additional surgery, the function of the deltoid muscle was recovered considerably.
The patient did not wish an additional surgery because he did not feel any significant
inconvenience in his daily activities. If his shoulder elevation function had been
seriously impaired, we would have scheduled nerve grafting with the sural nerve or
neurotization of the axillary nerve using the motor branch to the long head of the
triceps muscle as a secondary surgery.
Conclusion
We reported a young male case of axillary artery injury combined with delayed brachial
plexus palsy that occurred tardily due to compressive hematoma after blunt trauma
to the shoulder. The patient was saved from severe complications by early diagnosis
and immediate surgery. Surgeons should thoroughly consider injuries of axillary arteries
and/or their branches when dealing with patients with blunt trauma to the shoulder,
even in cases with normal or subtle X-ray findings and/or preserved distal pulses
at initial assessment to avoid overlooking this condition. Additionally, surgeons
should be aware that this condition may even occur in young people or can be associated
with secondary brachial plexus injury due to a hematoma. For treatment, not only reconstruction
of the injured axillary artery but also immediate exploration of the brachial plexus
is required, especially in cases with progressive nervous deficits after trauma to
avoid irreversible neurological damage.
Authors’ contributions
KM was responsible to this patient for the whole treatment and performed the surgery
as a main surgeon. MM and AY assisted KM in the surgery. HY and KO supervised the
surgery and gave several suggestions to complete this manuscript. All authors read
and approved the final manuscript.
Consent
The patient and his family were informed that data obtained would be submitted for
publication, and written consent was obtained from the patient and their relatives.
