Approach
Patients commonly present with injury plus paralysis of the shoulder muscles. Electrical testing with an electromyogram (EMG) allows the surgeon to see the extent and pattern of the injury, and also to plan surgical reconstruction.
Clinical history
Brachial plexus injuries are quite rare and can result from a variety of causes.
The patient may have a history of a motor vehicle accident, gunshot or stab wound, contact sport accident, or workplace accident during heavy physical labour. If there is no associated trauma the history should include considering alternative diagnoses such as Parsonage-Turner syndrome, neurofibromatosis, and poor surgical positioning.
Clinical examination
The most important consideration for diagnosis is the clinical examination. The main patterns of brachial plexus injury are consistent and should be looked for.
The most common presentation is upper trunk (C5 and C6 root equivalent) injury: paralysis of the shoulder muscles and biceps with numbness of the radial digits of the hand and the shoulder. The triceps, forearm, wrist, and hand strength are typically intact.
Additional involvement of the C7 root adds paralysis of the triceps and wrist/finger extensors; an associated loss is that of the latissimus dorsi.
Complete injury to all 5 nerve roots, where all tendons' reflexes are absent, results in a flail and insensate extremity, with lesser injuries causing weakness and paraesthesia. Complete injuries tend to require nerve reconstruction while lesser degrees of injury may require only surgical decompression and scar removal.
Electromyography (EMG)
Electrical testing is important in diagnosis and prognosis of brachial plexus injuries.
An EMG test 6 weeks after injury can show the specific pattern of root involvement as well as early recovery if present.[17] As time goes on, repeat testing can determine recovery or failure of progression, which is important in planning treatment.
If there is no recovery by 3 months, surgical planning is necessary based on the pathophysiological principle that denervation of skeletal muscle for 1 year leads to permanent paralysis.[18] Evaluation by a surgical specialist at this time allows planning of effective reconstruction.
MRI/CT myelography
MRI scanning and myelography of the cervical spine with or without CT imaging has been used to diagnose nerve root avulsion, which is a contraindication to nerve reconstruction with nerve grafting.[19][20]
However, nerve transfer techniques (rather than nerve grafting) are now the the treatment of choice for microsurgical repair.[1][21][22][23][24]
Radiological studies are therefore used primarily in situations where compression of the plexus by tumours or other anatomical structures (e.g., accessory cervical rib) along the course of the plexus is suspected.[20][25]
Use of this content is subject to our disclaimer