The Hip
Home » Joints » Shoulder » Work Up for Brachial Plexus Injuries

Work Up for Brachial Plexus Injuries

       

- See: brachial plexus


- Discussion:
    - hx: persistant pain > 6 months: (poor prognosis); 
    - diff dx:
          - breast cancer (lower plexus and painful)
          - radiation therapy (upper plexus and painless)
          - parsonage-turner syndrome : (may first affect suprascapular)
          - pancoast tumor:


- Exam: of Brachial Plexus:
     - vascular:
            - axillary artery avulsion (may be as high as 20%)
            - consider arteriogram;
     - neuro exam of the brachial plexus:
            - preganglionic vs postganglionic:
                   - preganglionic injuries have little potential for recovery;
            - supraclavicular deficits:
                   - suprascapular (supraspinatus);
                   - dorsal scapular (rhomboids);
                   - long thoracic (serratus): hence winging of scapula may indicate preganglionic injury;
            - infraclavicular deficits:
                   - medial and lateral pecotoral (pectoralis major and minor);
                   - thoracodorsal (latissimus): muscle is fired when patient coughs;
                   - subscapular (subscaplaris)
    - cords:
         - lateral cord: anterior divisions of the upper and middle trunk merge to form the lateral cord;
         - medial cord: anterior division from the lower trunk forms the medial cord
         - posterior cord:
               - posterior divisions merge to become the posterior cord;
               - shoulder abduction determines function of the axillary nerve;
               - wrist extension determines low radial nerve function and elbow extension determines high radial nerve function;
         - other:
               - median and ulnar nerve function are determined by examining finger and wrist motion;
               - elbow flexion evaluates musculocutaneous function;


- Radiographic Studies:
      - CXR: (elevated hemidiaphram) 
             - scapulothoracic dissociation
                    - lateral translation of the shoulder girdle (measured from spinous process to medial border of scapula and AC widening 
                    - associated w/ complete and permanent brachial plexopathy (and possible vascular injury);
                    - mortality rate of upto 10%
                    - ref: Scapulothoracic dissociation: a devastating injury.
      - C-Spine X-ray: (associated C spine fractures)
      - Arteriogram;
      - CT myelogram: (rarely need to get myelograms)
           - may be used to help dx a preganglionic lesion;
           - this study but should be delayed 6-12 wks, since a clot of blood may occlude the opening of pseudomenigocele;
           - finding of a large diverticula or meningocele is diagnostic for a preganglionic root avulsion (as opposed to a post ganglionic extra-foraminal rupture); 
           - ref: Imaging of posttraumatic brachial plexus injury

- EMG:
           - some authors advocate EMG after 7-10 days, noting that a normal sensory evoked potential obtained from an anesthetic finger indicates
                   that the lesion is preganglionic (otherwise there is a more distal nerve injury);
                   - problem with early EMG, is that preganglionic injuries may occur along w/ dorsal root ganglion injuries which will falsely
                           indicate a postganglionic injury, and inaddition, early EMG cannot distinguish between to axonotmesis and neurotmesis;
           - traditionally EMG has been performed at 3-4 weeks (look for F wave);
                   - w/ preganglionic lesion, see denervating potentials in segmental paraspinal muscles innervated by the posterior primary rami;
           - references:
                   - Sensory nerve conduction after traction injuries of the brachial plexus.  
                   - Clinical Diagnosis, Testing, and Electromyographic Study in Brachial Plexus Traction Injuries
                   - The role of somatosensory evoked potentials and nerve conduction studies in the surgical management of brachial plexus injuries
                   - Clinical examination versus routine and paraspinal electromyographic studies in predicting the site of lesion in brachial plexus injury.


- Initial Treatment:
      - avoid a sling because of the propensity to acquire a fixed internally rotated and flexed shoulder, and will have stiff elbow;
      - keep C-collar on and look for associatted C spine fractures
      - in children and adults, if biceps function has not return after 3 mo. then consider operation;


- Surgical Treatment:
      - Shoulder in brachial plexus injuries:
      - Steindler Flexorplasty:
      - w/ severe injury, one option is AEA if the shoulder muscles are functioning



Brachial plexus surgery.