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Intraoperative Medialization Laryngoplasty


Introduction

Medialization laryngoplasty or thyroplasty type I was first described and later popularized by Ishiki during the 1970s. Netterville first reported on the immediate medialization of the true vocal fold following skull base or head and neck surgeries involving the sacrifice of the vagus or recurrent laryngeal nerves.

  • Glottic insufficiency affects all laryngeal functions and may be caused by vocal fold:

    • Atrophy (i.e., presbylarynx, neuromuscular degenerative disease)

    • Weakness (i.e., paresis)

    • Paralysis

  • Glottic insufficiency impairs the function of the laryngeal sphincter leading to :

    • Poor protection of the tracheobronchial airways during swallowing (i.e., aspiration)

    • Reduction of efficiency and strength of the cough reflex

    • Elimination of physiologic positive pressure on expiration (helps to inflate the lungs)

    • Wide range of dysphonia and vocal fatigue

    • Decrease in the efficiency of a Valsalva maneuver; thus patients may exhibit problems splinting the thoracoabdominal muscles, which help with lifting and facilitating bowel movements

  • An immediate intraoperative thyroplasty is based on an empirical medialization of the true vocal fold. The patient’s true functional deficit cannot be assessed reliably under general anesthesia; thus the need for a subsequent revision is higher than a secondary thyroplasty performed under awake sedation.

  • The vast majority of patients will enjoy a satisfactory outcome resulting in adequate protection of the tracheobronchial tree against aspiration and normal or near-normal voice (vocal fatigue may be a persistent problem).

  • Professional voice performers may require adjunctive procedures, such as arytenoid repositioning, to reach an optimal result.

  • A seemingly adequate postoperative result may deteriorate in time due to re-accommodation of the implant (i.e., GOR-TEX strip) or vocal fold atrophy (more common in patients with a high-vagal lesion).

  • Surgical medialization of a paralyzed cord displaces the affected vocal fold toward the midline and augments its bulk to improve the glottic closure (it facilitates neuromuscular compensation by the unaffected contralateral side).

Key Operative Learning Points

  • A medialization laryngoplasty or thyroplasty type I involves the medialization of a paralyzed or paretic true vocal fold by the insertion of a paraglottic implant such as :

    • Silicone (premade and custom implants)

    • Polytetrafluoroethylene (GOR-TEX; W.L. Gore and Associates, Newark, DE)

    • Titanium alloy

    • Hydroxyapatite

    • Cartilage

    • Fascia

    • Acellular dermis

    • Adjustable balloon

  • Most frequently, an intraoperative thyroplasty involves implantation without the benefit of being able to be certain of the position of the window with respect to the position of the vocal fold or the immediate effect of the implantation upon the quality and strength of the voice or cough.

  • The surgeon creates a window in the thyroid cartilage and medializes the vocal cord using dimensions that have been determined to yield adequate results for most patients operated in the traditional way ( Fig. 6.1A ).

    Fig. 6.1, A, Approximate dimensions and position of the thyroplasty window. During an immediate thyroplasty, the window is opened as close to the inferior edge of the thyroid ala as possible while still preserving an inferior strut. B, The strap muscles and the perichondrium of the thyroid cartilage were divided at the midline and are being retracted from the thyroid ala en bloc. Stabilization of the larynx with a single or double hook greatly facilitates this dissection and opening of the window.

  • 20%–30% of patients will require revision surgery.

Preoperative Period

History

This procedure may be planned preoperatively in the patient with a history of having a tumor originating in the vagus nerve (i.e., vagal schwannoma or a glomus vagale requiring removal of the vagus nerve) or requiring the sacrifice of the vagus nerve in removing an adjacent tumor (i.e., carotid body tumor). In such situations, this procedure must be discussed with the patient. There are also instances in which the need for intraoperative thyroplasty may not be anticipated, such as accidental transection of the recurrent laryngeal nerve during thyroid surgery in which the patient may not have been prepared for this additional procedure.

Physical Examination

  • Examination of the neck must rule out the presence of masses, scars, or excessive subcutaneous adipose tissue, all of which may affect the choice and difficulty of the exposure.

  • A preoperative flexible fiberoptic laryngoscopy ascertains:

    • The position of the vocal fold (VFs) and arytenoids (horizontal and vertical planes) during normal and forced ventilation, vocalization, and cough

    • The muscle tone of the vocal folds

    • The bulk of the vocal folds

    • The integrity of the mucosa

  • Functional assessment of all lower cranial nerves is critical.

Imaging

Not necessary.

Indications

  • The decision to perform an immediate intraoperative thyroplasty is multifactorial and includes such variables as the needs and desires of the patient (e.g., profession, fitness, hobbies and interests), age, premorbid laryngeal and pulmonary function, and presence of other cranial nerve deficits.

  • An immediate intraoperative thyroplasty is indicated in patients who:

    • Undergo sacrifice of the vagus or recurrent laryngeal nerve during an oncologic resection

    • Suffered iatrogenic or penetrating trauma to the neck with injury to the vagus or recurrent laryngeal nerves

Contraindications

  • An immediate intraoperative thyroplasty is contraindicated in patients who show:

  • Glottic airway stenosis due to edema or abductor paralysis (or paresis) of the contralateral true vocal cord

  • Presence of a congenital or acquired coagulopathy (relative contraindication)

  • Strong aversion to accept the risks of the surgery or the possibility of needing a secondary revised procedure

Preoperative Preparation

  • If the possibility of an intraoperative medialization is anticipated, the surgeon must ascertain the function of the contralateral vocal fold by indirect mirror or flexible laryngoscopy.

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