How are stingers (brachial plexus injuries) diagnosed and managed using knowledge of dermatomes?

Diagnosis and Management of Stingers Using Dermatome Knowledge

Stingers (brachial plexus injuries) should be diagnosed by identifying the specific dermatome distribution of symptoms and managed based on severity, with return-to-play decisions guided by symptom resolution and absence of neurological deficits. 1, 2

Pathophysiology and Clinical Presentation

Stingers are traumatic transient neuropraxias affecting the cervical nerve roots or brachial plexus, commonly occurring in collision sports like football and rugby. They typically present as:

• Acute lancinating pain radiating down one upper extremity
• Burning or electric shock-like sensation following a specific dermatome pattern
• Unilateral symptoms (bilateral symptoms suggest more serious spinal cord injury)
• Possible temporary weakness or numbness in the affected limb
• Symptoms typically lasting seconds to minutes, occasionally hours 1, 2, 3

Dermatome-Based Assessment

Using dermatome knowledge is crucial for accurate diagnosis:

• C5 involvement: Pain/numbness in lateral arm and shoulder (deltoid region)
• C6 involvement: Pain/numbness in lateral forearm, thumb, and index finger
• C7 involvement: Pain/numbness in middle finger and posterior forearm
• C8/T1 involvement: Pain/numbness in medial forearm, ring and little fingers 4

Diagnostic Approach

1. On-field evaluation:

   • Assess dermatome-specific symptoms and motor function
   • Rule out cervical spine injury (test neck range of motion when appropriate)
   • Evaluate bilateral upper extremity strength and sensation
   • Test for Spurling's maneuver (neck extension and rotation to affected side causing symptom reproduction)

2. Off-field evaluation for recurrent or persistent symptoms:

   • MRI of cervical spine to identify stenosis or degenerative changes
   • Electrodiagnostic testing to detect chronic neurogenic changes
   • CT myelography for suspected nerve root avulsions 5, 4

Management Protocol

Acute Management:

1. Remove from play if symptoms persist
2. Ice application to neck and affected area for 15-20 minutes
3. Anti-inflammatory medications for pain control

Return-to-Play Criteria:

1. Complete resolution of symptoms
2. Full strength in affected myotomes
3. Normal sensation in affected dermatomes
4. Full, pain-free cervical range of motion

Special Considerations:

• First-time stinger with rapid resolution: May return to play same day if all criteria met
• Recurrent stingers: Require more thorough evaluation before return to play
• Persistent symptoms: Need complete neurological workup before return consideration 5, 1, 2

Prevention Strategies

1. Equipment modifications:

   • Properly fitted helmet and shoulder pads
   • Consider specialized neck rolls or cowboy collars
   • Kerr Collar to minimize head acceleration and force transmission 5

2. Technique adjustments:

   • Proper tackling technique (avoid head-down position)
   • Neck strengthening exercises
   • Core stability training

Warning Signs Requiring Further Evaluation

• Bilateral symptoms
• Persistent weakness beyond 24 hours
• Neck pain or limited range of motion
• History of multiple stingers
• Symptoms affecting multiple dermatomes 3

Prognosis

Most stingers resolve completely within minutes to hours. However, athletes with recurrent stingers, especially those with underlying cervical stenosis, may face restrictions in contact sports participation. The risk of recurrence remains unpredictable, making thorough evaluation and appropriate counseling essential 2, 3.

Understanding the specific dermatome distribution of symptoms is the cornerstone of proper diagnosis and management of stingers, allowing for appropriate return-to-play decisions and prevention of more serious neurological injuries.