ABSTRACT
Objective: High-energy impact to the head, neck, and shoulder can result in cervical spine as
well as brachial plexus injuries. Because cervical spine injuries are more common,
this tends to be the initial focus for management. We present a case in which the
initial magnetic resonance imaging (MRI) was somewhat misleading and a detailed neurological
exam lead to the correct diagnosis.
Clinical presentation: A 19-year-old man presented to the hospital following a shoulder injury during football
practice. The patient immediately complained of significant pain in his neck, shoulder,
and right arm and the inability to move his right arm. He was stabilized in the field
for a presumed cervical-spine injury and transported to the emergency department.
Intervention: Initial radiographic assessment (C-spine CT, right shoulder x-ray) showed no bony
abnormality. MRI of the cervical-spine showed T2 signal change and cord swelling thought
to be consistent with a cord contusion. With adequate pain control, a detailed neurological
examination was possible and was consistent with an upper brachial plexus avulsion
injury that was confirmed by CT myelogram. The patient failed to make significant
neurological recovery and he underwent spinal accessory nerve grafting to the suprascapular
nerve to restore shoulder abduction and external rotation, while the phrenic nerve
was grafted to the musculocutaneous nerve to restore elbow flexion.
Conclusion: Cervical spinal-cord injuries and brachial plexus injuries can occur by the same
high energy mechanisms and can occur simultaneously. As in this case, MRI findings
can be misleading and a detailed physical examination is the key to diagnosis. However,
this can be difficult in polytrauma patients with upper extremity injuries, head injuries
or concomitant spinal-cord injury. Finally, prompt diagnosis and early surgical renerveration
have been associated with better long-term recovery with certain types of injury.
INTRODUCTION
The high volume of brachial plexus injuries resulting from car and motorcycle accidents
has fomented interest in the field of peripheral nerve repair [1]. Such injuries, which mainly occur in young adults [2], can result from direct injury to the nerves or from traction / avulsion of cervical
nerve roots from the spinal cord [1]. This is the same population at highest risk for cervical spinal-cord injuries,
and the mechanisms of injury can be similar. The diagnosis of a brachial plexus injury
is best made by physical examination but this can be difficult in polytrauma patients,
and initial imaging studies can be misleading. Tremendous progress in microsurgical
techniques, enhanced knowledge of brachial plexus anatomy, increased precision of
diagnostic studies, coupled with improved nerve grafting techniques as well as increased
availability of donor nerves have eased some of the apprehension with which peripheral
nerve repair has been approached in the recent past [3], [4].
HISTORY
A 19-year-old healthy man presented after a high-speed injury to the right shoulder
and right upper chest during football practice. The patient immediately complained
of excruciating neck, shoulder, and arm pain and inability to move his arm.
The patient was seen at an outside institution where initial radiographic assessment
included cervical-spine CT, shoulder films (both without abnormality), and a cervical-spine
MRI that showed cord edema and swelling. The patient was transferred to our institution
for management of possible spinal cord injury.
Physical examination demonstrated right-sided paralysis of the deltoid, biceps, and
triceps. The patient was also unable to abduct the shoulder or extend the wrist; he
had decreased opposition of the thumb, decreased ulnar motion, decreased abduction
and adduction of the digits, as well as decreased grip strength. Additionally, he
exhibited C5–7 sensory loss and C8–T1 distribution hypoesthesia.
Further review of the MRI conducted after the incident showed evidence of prevertebral
swelling secondary to a tear of the anterior longitudinal ligament and the longus
colli, generalized swelling of the spinal cord with moderate increase in T2 signal
from C3–7, and findings consistent with cervical root avulsions at C5, C6, and C7
(Fig [1]). A subsequent CT myelogram was performed, which demonstrated a right pseudomeningocele
consistent with cervical root avulsion (Fig [2]).
Because of the presence of nerve avulsion and a low likelihood of spontaneous recovery
the patient underwent surgery 20 days after the incident. A standard supraclavicular
approach was used. The phrenic nerve was found to be intact. The musculocutaneous
branch was located and isolated. An 8 cm long sural-nerve graft was obtained from
the right leg and used to connect the phrenic nerve to the cut end of the musculocutaneous
nerve. Next, the suprascapular nerve was located. A functional segment of the spinal
accessory nerve was found along the posterior margin and this nerve was taken distally
and connected to the cut end of the suprascapular nerve. At short-term follow-up there
was slight contraction of the triceps and trapezius. Physical therapy and pain management
were continued, and electromyography (EMG) nerve conduction velocity (NCV) muscle
testing was scheduled for 6 months after surgery.
DISCUSSION
The recovery of shoulder abduction, external rotation, and elbow flexion are the primary
goals of surgical reconstruction following injury to the upper brachial plexus (C5–7).
The goal of surgery is to restore the patient’s ability to fully flex at the elbow
and obtain at least 90° of shoulder abduction and 110° of external rotation [2]. A patient’s capability of performing the activities of daily life is greatly enhanced
when these goals are met.
Determining the type, level, and extent of the brachial plexus injury is crucial for
the selection of patients who can improve with surgical reconstruction. Preganglionic
root injuries represent 70 % of new brachial plexus injuries and are usually addressed
with nerve transfers, pedicle muscle transfers, and functioning free-muscle transplantations
[4]. The differentiation between root rupture versus avulsion is especially important.
Many authors report that the presence of pseudomeningoceles, on either plain film
or CT myelography, is almost diagnostic for brachial plexus root avulsion [5]. There are a number of parameters that have been shown to impact the success of
surgical reconstruction after brachial plexus injury. The delay between injury and
nerve repair is particularly important: delays past 6 months can significantly reduce
postoperative improvement [1], [6]. A number of studies have shown that significant gain in function at the shoulder
and elbow may be expected in 80 % of patients if nerve graft or transfer is done within
3 weeks of the onset of injury [3]. Patient adherence to a regimen of occupational and physical therapy can help prevent
arthrosis, which can reduce the benefits of muscle renerveration [1], [6].
CONCLUSION
The correct diagnosis of brachial plexus injury can lead to early renerveration and
possibly better long term outcome. A high index of suspicion and a detailed neurologic
exam is key to the diagnosis especially in the setting of confounding factors such
as variable radiographic interpretation, and the presence of other injuries.
