Endocrine: Thyroidectomy

Thyroidectomy

Positioning

  • Arms Tucked
  • Neck Extended

Procedure

  • Identify the Thyroid:
    • Transverse “Kocher Incision”
      • 1-2 Fingerbreadths Above Sternal Notch
      • Traditionally 8-10 cm Long – Generally Shorter (5-6 cm) in Modern Practice
    • Divide Platysma
      • Superior Subplatysmal Flap Carried to Cricoid Cartilage
      • Inferior Subplatysmal Flap Carried to Sternal Notch
    • Divide Midline Raphe (Avascular Plane Between Strap Muscles)
  • Expose One Thyroid Lobe:
    • Dissect the Entire Anterior Capsule of One Thyroid Lobe from Medial to Lateral
    • Thyroid Gland is Rolled Medially to Expose the Posterior Capsule
    • Vessels to Ligate:
      • Middle Thyroid Vein (No Middle Artery) – At the Lateral Aspect
      • Superior Thyroid Vessels – To Superior Pole
      • Inferior Thyroid Vessels – To Inferior Pole
    • Caution:
      • Ensure Meticulous Intraoperative Hemostasis
      • Avoid Thyroid Capsule Rupture
      • Identify & Protect the Recurrent Laryngeal Nerve in the Tracheoesophageal Groove
      • Avoid Parathyroid Gland Devascularization or Resection
    • Dissect the Entire Posterior Capsule from Lateral to Medial
  • Medial Dissection:
    • Divide the Ligament of Berry as Close to the Trachea as Possible
      • Avoid RLN Injury
    • Dissect the Isthmus Off the Anterior Aspect of the Trachea
  • Next Step:
    • Thyroid Lobectomy: Divide the Thyroid at the Isthmus
    • Total Thyroidectomy: Repeat Dissection on the Contralateral Side
  • Finish & Close:
    • Obtain Hemostasis
    • Close Strap Defect
    • Close Platysma Defect
    • Close Skin

Thyroidectomy Incision 1

Thyroidectomy Showing Recurrent Laryngeal Nerve (Arrow) 2

Complications

Cervical Hematoma

  • Risk: 0.7-1.5%
  • Must Ensure Meticulous Intraoperative Hemostasis
  • Even Low-Volume Bleeding Can Cause Life-Threatening Airway Obstruction
  • Can Cause Airway Edema from Venous/Lymphatic Obstruction Making Intubation Difficult
  • Routine Drain Placement is Unnecessary
    • Generally Recommended for Persistent Oozing or Extensive Dissections
  • Treatment:
    • Respiratory Distress: Emergently Open at Bedside
    • Not in Respiratory Distress: Intubate & Emergently Open in the OR

Nerve Injury

  • Risk:
    • Recurrent Laryngeal Nerve Injury: 0-11%
    • Bilateral Vocal Cord Paralysis: 0.4%
  • Prevention:
    • Indications for Preoperative Laryngoscopy:
      • Preoperative Hoarseness or Voice Changes
      • History of Neck or Mediastinal Surgery
      • Posterior Extrathyroidal Extension of Tumor
      • Bulky Lymphadenopathy
      • *Routine Assessment Unnecessary
    • Intraoperative Nerve Monitoring (IONM):
      • Surface Electrodes on the Endotracheal Tube Sense When the Recurrent Laryngeal Nerve is Stimulated
      • Generally Recommended if There is a History of Prior Neck Surgery
      • *Routine Use is Controversial
  • Most Common Nerve Injury: Superior Laryngeal Nerve (SLN)
  • Most Common Site of RLN Injury: Ligament of Berry
  • If Recurrent Laryngeal Nerve (RLN) Transection Identified Intraoperatively: Primary Anastomosis
    • May Use Ansa Cervicalis Nerve Graft to Avoid Tension

Transient Hoarseness

  • Common After Thyroid Surgery
  • Caused by Vocal Cord Edema from Endotracheal Intubation
  • Generally Resolves After 24-48 Hours
    • Persistent Hoarseness Should Raise Concern for Vocal Cord Motion Abnormality

Hypothyroidism

  • Surgical Risk:
    • Total Thyroidectomy: All Have Postoperative Hypothyroidism
    • Lobectomy/Hemithyroidectomy: At Risk for Postoperative Hypothyroidism (Risk: 22%)
      • Smaller Size Residual Thyroid Tissue Increases Risk
      • Labs Should Be Drawn at 4-6 Weeks Postop to Evaluate
  • Staging:
    • Subclinical Hypothyroidism: Elevated TSH & Normal Free T4
      • Most Often Asymptomatic
      • Often Can Progress to Overt Hypothyroidism
    • Overt Hypothyroidism: Elevated TSH & Low Free T4
      • Mostly Symptomatic
  • Treatment: Thyroid Hormone (Levothyroxine) Replacement
    • Subclinical Cases After Hemithyroidectomy Should Still Be Treated Even if Asymptomatic
    • Patients After Total Thyroidectomy will Require Lifelong Hormone Replacement

Hypoparathyroidism

  • Transient Hypoparathyroidism/Hypocalcemia (1-49%)
    • Common Even When Parathyroid Glands are Meticulously Preserved
    • Liberal Use of Calcium & Vitamin D Supplementation Encouraged After Total Thyroidectomy
  • Permanent Hypoparathyroidism (2%)
    • From Inadvertent Parathyroid Gland Devascularization or Resection

References

  1. Wikimedia Commons. (License: Public Domain)
  2. THWZ. Wikimedia Commons. (License: CC BY-SA-3.0)