Persistent Paresthesia in the Posteromedial Aspect of the Upper Arm Following SLNM/SLNB

• The symptoms of neuropathy are due to injury of the intercostobrachial nerve:
  • This nerve is a cutaneous branch of the intercostal nerves:
    • Most commonly the second intercostal nerve:
      • Which gives off a lateral cutaneous nerve:
        • Which continues as the intercostobrachial nerve
  • The intercostal nerves arise from the anterior rami of the thoracic spinal nerves

• The intercostobrachial nerve pierces the serratus anterior, and crosses the axilla to the medial side of the upper arm:
• The intercostobrachial nerve is commonly in the surgical field during axillary lymph node dissections and may be severed during surgery, or subject to traction or postsurgical inflammation:
  • Thus leading to intercostobrachial neuralgia
• The larger intercostal nerves can be preserved with meticulous dissection
• Neuropathic symptoms:
  • May be limited to numbness or tingling, but may also include a burning sensation
• Techniques such as a regional nerve block have been described to alleviate symptoms in severe cases
• In a study of 200 patients who underwent axillary dissection:
  • 76% had symptoms of intercostobrachial neuralgia postoperatively:
    • Of these patients, 82% reported improvement or resolution of these symptoms within 1 year:
      • Reflecting the richness of the sensory nerve supply to the axilla and upper arm
• The thoracodorsal nerve:
  • Is a branch of the posterior cord of the brachial plexus:
    • Supplies motor function to the latissimus dorsi

• If injured:
  • Patients experience weakness with arm abduction, lateral flexion, and difficulty with activities such as climbing, swimming, and using the arms to pull the body up

• The medial cord of the brachial plexus gives rise to the medial pectoral nerve:
  • Which innervates both the pectoralis minor muscle and the pectoralis major muscle
  • The medial pectoral nerve typically pierces the pectoralis minor muscle, but may wrap around the lateral aspect of the pectoralis minor before traveling on to innervate the distal pectoralis major muscle
• The lateral cord of the brachial plexus:
  • Gives rise to the lateral pectoral nerve, which innervates the pectoralis major muscle
  • This nerve travels along the medial border of the pectoralis minor muscle, and then along the undersurface of the pectoralis major muscle along with the pectoral branch of the thoracoacromial artery to supply the proximal pectoralis major muscle
• The medial pectoral nerve bundle is often encountered during axillary dissection, as it is located lateral to the lateral pectoral nerve
• If either of these nerves is injured, pectoralis muscle atrophy can occur, which can present as a late complication of surgery:
  • With weakness of shoulder adduction, interior rotation, and flexion
• The long thoracic nerve:
  • Typically arises from anterior rami of the cervical spinal nerve roots C5 to C7:
    • It courses along the chest wall and supplies the serratus anterior muscle
    • Injury to this nerve causes a winged scapula
• References
• Sclafani LM, Baron RH. Sentinel lymph node biopsy and axillary dissection: added morbidity of the arm, shoulder and chest wall after mastectomy and reconstruction. Cancer J. 2008;14(4):216-222.
• Wisotzky EM, Saini V, Kao C. Ultrasound-guided intercostobrachial nerve block for intercostobrachial neuralgia in breast cancer patients: a case series. Prev Med Rep, 2016;8(3):273-277.

• Roses DF, Brooks AD, Harris MN, Shapiro RL, Mitnick J. Complications of level I and II axillary dissection in the treatment of carcinoma of the breast. Ann Sur. 1999;230(2):194-201.
• Porzionato A, Macchi V, Stecco C, Loukas M, Tubbs RS, De Caro R. Surgical anatomy of the pectoral nerves and the pectoral musculature. Clin Anat. 2012;25(5):559-575.

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