Vocal Cord Cordectomy

Background

Cordectomy involves removal of the entire membranous vocal fold with the vocalis muscle. The inner perichondrium of the thyroid cartilage can be included and the arytenoids cartilage can also be removed, either partially or completely. ^[1] Cordectomy via thyrotomy is the oldest surgical procedure for the treatment of early glottic carcinoma. ^{[2, 3]} It remains the standard by which all other surgical treatments of small glottic cancers are measured. ^[1]

Cordectomy can be performed by the following 2 methods:

1. Cordectomy through laryngofissure

2. Endoscopic laser cordectomy

In 1908, Citelli introduced the so called cordectomy externa through thyrofissure. ^{[4, 5]} Chevalier Jackson described total cordectomy to treat patient with airway obstruction from bilateral vocal folds inability (1922) but the procedure was hampered by the resultant poor voice quality. ^[6] In 1932, Hoover published the results with similar approach through laryngofissure. ^[7] An important new concept was the submucosal dissection, which later became a standard. The preservation of the overlying mucosal allowed primary wound closure. Surjan further improved the concept of the submucosal approach through laryngeal fissure. ^{[8, 5]} Dennis and Kashima described posterior cordectomy for the treatment of bilateral vocal folds inability in 1989. ^{[9, 10]}

Images depicting cordectomy can be seen below.

Relevant anatomy

The vocal folds, also known as vocal cords, are located within the larynx (also colloquially known as the voice box) at the top of the trachea. They are open during inhalation and come together to close during swallowing and phonation. When closed, the vocal folds may vibrate and modulate the expelled airflow from the lungs to produce speech and singing. For more information about the relevant anatomy, see Vocal Cord and Voice Box Anatomy.

Indications

Vocal cord cordectomy is indicated in the treatment of the following:

• Dysplastic lesions of the vocal cords

• Vocal cord malignancies- T1 lesions

• Bilateral abductor paralysis

Contraindications

Cordectomy is contraindicated in the following cases:

• When the vocal cords' mobility is impaired.

• When the thyroid cartilage is invaded by the tumor.

• When supraglottic or subglottic extension exists. ^[1]

Endoscopic laser surgery is contraindicated if general anesthesia is a threat to the patient’s life, such as in the following cases:

• Recent infarct

• Patient with aneurysms

• Bradycardia, etc

But, an increased risk is justified in patients with suspected malignancy. ^[11]

Endoscopic laser surgery is not possible in patients with the following conditions:

• Ankylosing spondylitis

• Fracture of cervical spine

• Mandibular deformity

• Patients with short thick neck associated with marked prognathism. ^[11]

Types of cordectomy

Cordectomy can be performed by the following 2 methods depending on the indication:

• Endoscopic laser cordectomy

• Laryngofissure with cordectomy

A classification of laryngeal endoscopic cordectomies was first proposed by European laryngology society in 2000.The classification described 8 types of cordectomies, as follows: ^{[12, 13]}

• Type I: Subepithelial cordectomy, which is the resection of vocal cord epithelium passing through the superficial layer of lamina propria .

• Type II: Subligamental cordectomy, which is resection of epithelium, or Reinke’s space and vocal ligament.

• Type III: Transmuscular cordectomy, which proceeds through vocalis muscle.

• Type IV: Total cordectomy, which extends from vocal process to the anterior commissure.

• Type Va: Extended cordectomy encompassing the contralateral vocal fold.

• Type Vb: Extended cordectomy encompassing the arytenoids.

• Type Vc: Extended cordectomy encompassing the ventricular fold.

• Type Vd: Extended cordectomy encompassing the subglottis.

This classification did not propose any specific management for the lesions arising from the anterior commissure, which are being included among the indications for type Va cordectomy. To solve this problem, new cordectomy, encompassing the anterior commissure and anterior part of vocal cord, was proposed by European laryngology society working committee on nomenclature. This is classified as type VI.

Type VI is indicated for cancer originating in the anterior commissure involving one or both the vocal cords, without infiltrating the thyroid cartilage. ^[12]

European Laryngological Society classification allows one to define and clearly distinguish the extent of excision, which facilitates making meaningful comparisons between vocal outcomes after different types of cordectomy.

Preparation

Anesthesia

Atropine is always included in premedication. Anesthesia is induced by intravenous injection of barbiturates or by application of gas mixture via a mask. Relaxation is usually achieved by a bolus of succinyl choline. A long term relaxant is preferred for cordectomy. The anesthetic usually consists of gas mixture such as halothane, nitrous oxide and oxygen. ^[11] For more information, see general anesthesia.

Equipment

• Various laryngoscopes, including bivalve adjustable laryngoscopes are used to expose the larynx.

• Two suction devices: one is mounted on to the operating microscope and the other suction is used by the surgeon to evacuate the plume and to manipulate the tissue.

• Microlaryngeal surgery instruments

• Carbon dioxide laser coupled to an operating microscope

• Laser safe endotracheal tubes. ^[14]

Positioning

The correct position is essential for the optimal introduction of laryngoscope. The patient should preferably lie horizontally flat on operating table, with neither head ring nor sand bag under the shoulders. The dental plate is put in place before the laryngoscope is introduced. ^[11]

Approach

Endoscopic laser cordectomy

The procedure begins with the orotracheal intubation with a laser-safe endotracheal tube. The patient’s eyes are then taped and padded and a head drape and upper tooth guard is applied. ^[15] When the patient is fully relaxed and sufficiently anaesthetized, a largest possible laryngoscope is introduced to get a good view of larynx. ^[11]

Before introducing the laryngoscope, the patient’s head is fully extended, and the laryngoscope is introduced between the endotracheal tube behind and lower jaw in front. Under visualization, laryngoscope is gently pushed forwards following the endotracheal tube between the epiglottis and the tube until the point reaches the petiole of epiglottis. If laryngoscope is passed too deeply into the larynx, both the vestibular fold and vocal folds are displaced laterally, whereas if the scope is not passed deeply enough the vestibular folds obscure the vocal cords. Once the laryngoscope is correct position, the chest holder is put in place to fix the scope in position. After exact adjustment of the scope, both vocal cords can be seen as far as the apex of vocal process. Once the laryngoscope is in the desired position, the light carrier is removed and an operating microscope is used. ^[11]

The patient’s head and face are protected with moist towels and the operating microscope, which is fitted with a microspot carbon dioxide laser and 400 mm lens is brought into position. To protect the endotracheal tube cuff, a moist cottonoid sponge is placed in the subglottis. Dissection is begun posteriorly and laterally. Medial retraction of the edge of the lesion shows the plane of dissection as the surgeon dissects anteriorly and inferior edge is resected at the end. A curved trajectory that parallels the contour of the normal vocal fold is used, and the depth of the excision is tailored to the lesion. ^[15]

The 30º- or 70º-angle telescope introduced through laryngoscope can be used with the advantage of examining the laryngeal surface of epiglottis, lateral wall of larynx, and subglottic space. ^[11]

A brief description of different types of cordectomies is given below. ^{[12, 13, 14, 16]}

Type I: Subepithelial cordectomy

This involves the resection of vocal fold epithelium, passing through the superficial layer of the lamina propria. It is performed for premalignant lesions and lesions that show malignant transformation. Usually entire vocal cord epithelium is resected and in rare cases, clinically normal epithelium may be preserved. Since subepithelial cordectomy ensures histopathological examination of entire vocal cord, the main role of this surgical procedure is diagnostic. This procedure can also be therapeutic if histological results confirm hyperplasia, dysplasia, or carcinoma in situ without signs of microinvasion.

Type II: Subligamental cordectomy

This is indicated for cases of microinvasive carcinoma or severe carcinoma in situ with possible microinvasion. In this procedure vocal cord epithelium, Reinke space, vocal ligament are resected by cutting between the vocal ligament and vocalis muscle. The resection may extend from the vocal process to the anterior commissure and vocalis muscle is preserved as much as possible.

Type III: Transmuscular cordectomy

This procedure is indicated for small superficial lesions of the mobile vocal folds that reaches the vocalis muscle and without deeply infiltrating it. This involves the resection of epithelium, lamina propria and the part of vocalis muscle. The resection may extend from the vocal process to the anterior commissure. In some cases, partial resection of the ventricular fold may be required for adequate visualization of the vocal fold (see video below).

Type IV: Total or complete cordectomy

This procedure is indicated for T1a lesions infiltrating the vocalis muscle. The resection extends from the vocal process to the anterior commissure and attachment of vocal ligament to the thyroid cartilage should be cut. The depth of the surgical margins reaches the internal perichondrium of the thyroid cartilage and sometimes perichondrium is included with resection.

Type Va: Extended cordectomy encompassing the contralateral vocal fold

This surgical approach was meant to include the anterior commissure and, depending on the extent of tumor, either a segment or the entire contralateral vocal fold. This procedure is now replaced by type VI cordectomy.

Type Vb: Extended cordectomy encompassing the arytenoids

This procedure is indicated for vocal fold carcinoma involving vocal process or arytenoid cartilage posteriorly. For this type of resection, arytenoid cartilage should be mobile, and the cartilage is partially or fully resected.

Type Vc: Extended cordectomy encompassing the ventricular fold

This procedure is indicated for ventricular cancers or trans glottis cancers that spread from vocal fold to the ventricle. This involves the resection of ventricular fold and Morgani’s ventricle.

Type Vd: Extended cordectomy encompassing the subglottis

This procedure can be used for selected cases of T2 carcinoma with limited subglottic extension without cartilage invasion.

Procedure of type VI cordectomy

This procedure is indicated for cancer originating in the anterior commissure involving one or both the vocal cords, without infiltrating the thyroid cartilage. The surgery comprises anterior commissurectomy with bilateral anterior cordectomy. If the tumor is in contact with cartilage, resection can encompass anterior part of thyroid cartilage. Resection of the anterior commissure may include the subglottis mucosa and cricothyroid membrane, because cancers of anterior commissure tend to spread toward the lymphatic vessels of the subglottis.

The pharynx and teeth should be checked for damage before extubating from anesthesia.

Laryngofissure with cordectomy

Open cordectomy has been used in the surgical management of glottis malignancies with good cure rates. It can be used in patients with T1 lesions who are not amenable to laser cordectomy because of inadequate endoscopic visualization. After a preliminary tracheotomy, a horizontal skin crease incision is made at the middle part of the larynx. Subplatysmal flaps are elevated, and strap muscles are separated along the midline and larynx is exposed. Thyroid cartilage is examined for any signs of invasion. The perichondrium of the thyroid cartilage is elevated in the midline and elevated slightly to both side and thyroid cartilage is cut in the midline. ^[15]

If the anterior commissure is involved, the vertical thyrotomy incision is made off-center on the uninvolved side. After opening the larynx, the tumor is identified and involved cord is resected with a 1-2 mm mucosal margin. In rare cases, small lesions on both vocal cords can be resected simultaneously by this technique. ^[1]

For cases requiring superficial cordectomy, no reconstruction is required to achieve a good postoperative voice. If the surgical resection extends deeply in to the thyroarytenoid muscle or to the inner perichondrium, false vocal cord tissue may be swung down to fill the defect. The thyrotomy is closed with interrupted 3-0 Vicryl sutures. ^[15]

Posterior cordectomy for bilateral abductor palsy

Using carbon dioxide laser, 3.5-4 mm C-shaped wedge of posterior vocal cord is excised from the free border of the membranous cord, anterior to the vocal process, extending 4 mm laterally over ventricular band. Excision should be done anterior to the vocal process and cartilage should not be exposed. This surgical resection creates 6-7 mm transverse opening at the posterior larynx. ^[17]

Some authors recommend simultaneous bilateral posterior cordectomy for the management of bilateral abductor palsy. ^[18]

Complications

Complications of endoscopic cordectomies are as follows: ^{[11, 19, 20, 21]}

• General complications include circulatory and respiratory disorders resulting from anesthesia.

• Local injuries such as injury to the teeth, tearing and laceration of palate. Laceration, hematoma of lips or tongue can usually be prevented by careful introduction of laryngoscope. These injuries are caused by pressure of the laryngoscope on the base of tongue or oropharynx. Deeper laceration should be sutured immediately and antibiotics should be given to prevent parapharyngeal extension of infection.

• Bleeding from larynx during or after operation may be present after cordectomy. Hemostasis can usually be achieved by adrenaline-soaked pledgets or deliberate coagulation. Massive bleeding may demand ligation of superior laryngeal artery.

• Postoperative edema is uncommon and prophylactic steroids can be used to prevent edema.

• Granuloma scars and adhesions can develop after surgery.

• Phonatory outcome after few types of transoral laser surgery may not be satisfactory and they may require an additional phonosurgical procedure. ^[14]

• Cordectomy patients aspirate food and saliva if the edge of the scar is not in the midline and it cannot be swelled out with Teflon because it is very hard and elastic. ^[22]

Long-term monitoring

Endoscopy under general anesthesia should be carried out at least every 2 months for first two years after surgery and with decreasing frequency in the subsequent years.

Adjunctive phonosurgical treatment is not required after type I and II cordectomy because postoperative conversational voice obtained after a standard voice therapy protocol and vocal hygiene, including voice rest for at least 2 weeks after surgery. For type III cordectomy, Eckel et al recommends a primary intracordal autologous fat injection at the end of the endoscopic resection. ^[14] A potential shortcoming of this technique is the variable resorption rate of the injected fat. Some authors prefer to perform phonosurgical voice rehabilitation only following a disease-free interval of at least 6 months to 1 year. In patient with types IV and V cordectomy, a wider glottic gap usually reduces the possibility of good glottic closure, and the fibrotic nature of the neocord prevents any mucosal wave. These patients can be treated after one year by appropriate phonosurgical procedures. ^[14]

Patient education

Most important prerequisite for endoscopic management of laryngeal tumors is ensuring adequate patient compliance to a compulsive post operative follow-up. ^[14]

Postoperative care

See the list below:

• Absolute voice rest

• Coughing and clearing of throat, singing and shouting should be avoided

• Coughing should be treated by cough suppressants and mucolytic agents

• Steam inhalation should be done twice daily

• Antibiotic therapy with appropriate antibiotics ^[11]