Medialization Thyroplasty

Description:

Medialization, or Isshiki type I, thyroplasty is used to move an immobile or hypomobile vocal fold into an adducted position. This reduces the risk of aspiration and improves vocal quality in cases of unilateral vocal fold paresis or paralysis.

Indications for Surgery:

Unilateral vocal fold immobility resulting in symptomatic glottic insufficiency (e.g., aspiration or inadequate voice production).

Contraindications to Surgery:

  • Medical comorbidities that would preclude surgical or anesthesia risk

Pre-Operative Evaluation:

  • Vocal fold immobility is diagnosed by flexible fiberoptic laryngoscopy or transoral rigid laryngoscopy.
  • Medialization thyroplasty should only be pursued in situations where vocal fold paralysis is permanent, and the functional vocal fold is unable to compensate. A period of observation is required before proceeding with surgical intervention (usually one year), unless poor prognosis is predicted by laryngeal electromyography.
  • If dysphonia is the indication for surgery, a trial of voice therapy should be completed before pursuing thyroplasty.
  • If no inciting event (e.g., trauma, antecedent surgery) can be identified as the cause of vocal fold paralysis, a computed tomography (CT) scan with intravenous contrast should be performed from the skull base to the aortic arch to rule out presence of a mass lesion affecting the vagus or recurrent laryngeal nerves. Laryngeal electromyography may also be performed to determine whether the condition is a result of a muscular or neurologic disorder.

Anesthesia:

Monitored anesthesia care (MAC)

Surgical Technique:

  1. The patient is placed supine on the operating table and intravenous sedation is administered.
  2. The neck is extended, and the anterior neck is prepped and draped in sterile fashion.
  3. The skin of the anterior neck is injected with 1% lidocaine with 1:100,000 epinephrine.
  4. A transverse skin incision is made at the level of the cricothyroid membrane.
  5. Subplatysmal flaps are elevated, the strap muscles are divided in the midline, and the thyrohyoid muscle is swept off the lateral thyroid ala.
  6. In cases of a large posterior glottic gap, an arytenoid adduction or adduction arytenopexy may be performed at this time.
  7. An oscillating saw is used to create an anteroinferiorly-based window in the thyroid cartilage.
  8. The periglottic musculature is elevated away from the inner thyroid ala.
  9. The patient’s anesthesia is lightened and the voice is tested as the periglottic musculature is displaced medially.
  10. A Silastic block is then cut to shape in a wedge fashion and inserted into the window in the thyroid cartilage. Alternatively, an expanded polyterafluoroethylene (Gore-Tex) sheet or a pre-formed Montgomery implant may be used.
  11. The voice is again tested, and the implant is modified until optimal voicing is obtained.
  12. The implant is secured in place with suture.
  13. The wound is irrigated and checked for hemostasis.
  14. The strap muscles are closed, a Penrose drain may be placed, and the incision is repaired in two layers. Dermabond is applied to the skin and a sterile dressing is applied.
  15. Care of the patient is returned to the anesthesiologist for recovery.

Post-Operative Care

  • The patient is admitted overnight for airway monitoring.
  • Upon discharge, the patient is instructed to seek medical attention if voice changes, bleeding, or airway compromise occur.
  • Post-operative voice therapy is initiated 1-2 weeks after surgery.
  • A follow-up visit should be arranged in 3-4 weeks.

Complications:

  • Bleeding/hematoma
  • Insufficient or excessive medialization
  • Migration of the implant
  • Implant infection
  • Creation of posterior glottic gap
  • Airway compromise



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