Vocal Cord Cordotomy

Background

Endoscopic laser posterior cordotomy is performed in patients with bilateral vocal fold paralysis in adduction.[1] It is considered as an alternative procedure to tracheotomy.[2, 3, 4]

Laser cordectomy was first described in 1989 by Kashima.[5] In 1999, Friedman et al described the application of the cordotomy in children from 14 months to 13 years old.[6] The technique was effective and associated with good functional results.[2]

Surgical treatment for bilateral vocal fold paralysis should aim at a compromise between respiratory and phonatory performance and should be adjusted according to patient’s needs.[7, 8, 9]

An image depicting vocal cord cordotomy 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

Laser posterior cordotomy is a minimal invasive procedure done for the bilateral vocal fold paralysis in midline position.[2]

Surgical management to address bilateral vocal fold paralysis is generally undertaken in tracheotomy-dependent patients with a goal of decannulation.[10]

Contraindications

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

• Recent infarct

• A patient with aneurysms

• Bradycardia[11]

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

• Ankylosing spondylitis

• Fracture of the cervical spine

• Mandibular deformity

• A patient with a short, thick neck associated with marked prognathism[11]

Relative contraindications for endolaryngeal laser surgery of vocal folds are persistent vocal fold edema and inflammation that cannot be resolved.[7]

Advantages of Cordotomy

Cordotomy has become a procedure of choice for the treatment of bilateral vocal fold paralysis for the following reasons:[2]

• The procedure is short and reduces the time of anesthesia.

• Cordotomy is quite easy to perform, and the technique is quickly acquired.

• It can be proposed as an alternative to tracheotomy even at the time of diagnosis.

• Cordotomy is considered as a minimal invasive procedure because functional results as swallowing and voice quality are good.

• It can be proposed even if the patient later recovers spontaneously.

• Vocal fold tissue is not significantly excised.

• The cordotomy only frees the vocal ligament and the vocal muscle from the vocal process of the arytenoids. Tissue retraction enlarges the airway.

• Because of the small size of the larynx in children, this procedure is often sufficient and safe.

Preparation

Anesthesia

This procedure is performed under general anesthesia. In the absence of a pre-existing tracheotomy, a small laser-protected endotracheal tube is placed. If a tracheotomy is present, the patient is intubated via the stoma with a laser-safe endotracheal tube.[12]

Some authors recommend endoscopic carbon dioxide laser posterior cordotomy without tracheotomy, believing that the minimal postoperative edema does not compromise respiration.[7]

Antibiotics, steroids, and H2 blockers are given intraoperatively.[12]

Equipment

• Various size laryngoscopes, including bivalve adjustable laryngoscopes

• 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

• Laser safe endotracheal tubes[13]

• Carbon dioxide laser coupled to an operating microscope

• KTP-532 laser can also be used[7, 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

See the list below:

• 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, the largest possible laryngoscope is introduced to get a good view of larynx. Once the laryngoscope is correctly positioned, 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. When 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.[15]

• The site of cordotomy is determined at the preoperative examination or under spontaneous ventilation anesthesia. If one vocal fold seems to have a light degree of motion, the cordotomy is performed on the opposite side. Undercorrecting is better than risking the voice and vocal functions. When the first procedure is not sufficient, a second one is possible (cordotomy homolateral or contralateral), with a good result after this procedure.[2]

• Carbon dioxide laser with 0.2 mm spot size and a power setting of 3-5 Watts is used. Using carbon dioxide laser, a cordotomy is performed 1-2 mm anterior to the vocal process. This is carried laterally through the width of the vocal ligament and the vocalis muscle to the thyroid lamina. The cordotomy both opens the air way posteriorly and provides access to the arytenoid cartilage. Postoperatively, patient is maintained on antibiotics and antireflux medications until mucosal healing is complete (see the images below).[12]

  Diagram showing cordotomy incision (blue dotted line) on the posterior part of right vocal cord.

  Diagram showing the result of cordotomy incision on the posterior part of right vocal cord.

See the list below:

• Anti-gastroesophageal reflux treatment is given for 8 weeks.

• Oral antibiotic are given for 1 week.

• Endoscopy should be performed 3 days after the procedure, when the KTP laser is used, in order to clean the fibrinous residues. When carbon dioxide laser is used, the follow-up is done using flexible endoscopes.

• The resulting voice quality is fair to good, and most patients with tracheotomy can be decannulated within 6 weeks of the procedure once mucosal healing is complete.[2]

Complications

Complications are as follows:[7, 14]

• Postoperative edema

• Granuloma

• Scar formation

• Posterior glottic web

• A rare but possible complication during endolaryngeal carbon dioxide laser surgery is ignition of the gas mixture within the airway, with involvement of the endotracheal tube.[16]