Vertical Partial Laryngectomy
Jonas T. Johnson
Vertical partial laryngectomy (VPL) is a surgical procedure that has been developed to preserve laryngeal function during the treatment of invasive cancer. Hemilaryngectomy refers to a procedure in which a single vocal fold is excised, employing a transcervical approach in which the deep margin is the ipsilateral thyroid cartilage. This procedure is largely obsolete for the primary treatment of small vocal fold lesions because most of these lesions can be removed endoscopically with good oncologic results and preservation of vocal function.
Frontolateral hemilaryngectomy is an appropriate term used to describe an external approach for laryngeal cancer in which the anterior commissure is resected with the overlying thyroid cartilage. Once again, this procedure has largely been replaced by endoscopic approaches but may occasionally be employed for patients in whom the larynx cannot be adequately exposed endoscopically. VPL was designed to treat patients with small cancers (T1 and T2) limited to the true vocal fold. This generally means that they can have no more than 10 mm of subglottic extension. Involvement of one arytenoid can be encompassed through resection and reconstruction of that arytenoid; however, involvement of both arytenoids is a contraindication to this procedure. Similarly, extension to involve the supraglottis is a contraindication to partial vertical laryngectomy.
Cancer of the true vocal fold almost always presents initially with dysphonia. The diagnosis requires clinical suspicion, recognition of an abnormality on clinical examination in the office, and histologic confirmation through biopsy. The overwhelming majority of patients with laryngeal cancer have squamous carcinoma, which is associated with exposure to cigarette smoke. Inasmuch as 5% of patients may present with simultaneous second primary squamous carcinoma, a detailed history and comprehensive physical examination including endoscopic evaluation of all of the mucosal surfaces of the upper aerodigestive tract is recommended. The value of routine bronchoscopy and esophagoscopy is controversial and not routinely employed by me, unless symptoms or radiographic findings suggest additional pathology.
Transnasal flexible laryngoscopy in the office is appropriate for any patient with hoarseness. Assessment of the extent of tumor and vocal fold mobility offers the surgeon an estimate of the depth of invasion and helps to stage the cancer. Videostroboscopy may offer further clues about depth of invasion and the suitability for endoscopic transoral resection.
Physical examination should include careful palpation of the neck to include assessment of a potential delphian node at the cricothyroid membrane. Pathologic adenopathy suggests advanced disease and in the setting of a very limited lesion of the true vocal fold, may indicate a second primary cancer.
VPL may be the ideal laryngeal conservation procedure for certain patients who have failed radiation therapy for small (T1 and T2) glottic cancers. VPL is largely obsolete for previously untreated T1 and T2 glottic cancers, inasmuch as these tumors can be removed endoscopically in most circumstances. Frontolateral vertical laryngectomy is a suitable alternative for lesions involving the anterior commissure and yields better oncologic results than primary radiation therapy. This improved local control comes at the expense of moderate dysphonia in all patients. Fewer than 5% of patients require total laryngectomy for recurrence of these early cancers.
Tumor extension to involve the supraglottic larynx is a contraindication to VPL. Similarly, involvement of more than 10 mm of subglottic mucosa, the laryngeal cartilaginous framework, or involvement of both arytenoids should always be considered a contraindication. Patients with severe comorbidities may be better served with a nonsurgical management scheme.
Patients judged to be suitable candidates for partial vertical laryngectomy may benefit from fine-cut computed tomography (CT) of the larynx to allow the surgeon better assessment of the depth of invasion and subglottic involvement. CT should also confirm the absence of adenopathy. Tumor that extends more than 10 mm below the vocal fold or the presence of paraglottic invasion is a contraindication to this procedure.
In the setting of failed primary radiation therapy, an accurate assessment of the original size and location of the primary tumor facilitates treatment planning. In this regard, there is little substitute for having seen the cancer yourself prior to radiation therapy. Modern imaging will not completely localize multifocal recurrent disease, which, in turn, explains the need for total laryngectomy employed for many patients facing this problem.
When partial vertical laryngectomy is deemed appropriate, the surgeon can enhance the planning process through direct microlaryngoscopy and direct inspection of the larynx and palpation of the vocal cords prior to definitive resection. When the anterior commissure is involved, it allows the surgeon to estimate the need and amount of contralateral true vocal fold, which must be removed. It allows confirmation of whether there is <10 mm of subglottic extension, and it allows the surgeon to reassure himself that at least one arytenoid can be preserved.
When both arytenoids can be preserved, chronic aspiration is rarely a postoperative problem. Accordingly, even patients with moderately severe chronic obstructive pulmonary disease may be candidates. All patients, however, should be counseled that temporary tracheostomy and a nasogastric feeding tube will be required.
At the time of direct laryngoscopy, the surgeon can confirm for himself the potential need for reconstruction of either the anterior commissure or an arytenoid. In general, at least two-thirds of one membranous vocal fold is required to allow primary closure with an adequate airway. When tumor requires resection of more than one-third of both vocal folds, I recommend reconstruction of the lumen of the airway with an epiglottopexy to prevent stenosis of the larynx.
Resection of the vocal process of the arytenoid can be routinely undertaken without special intervention; however, when the entire arytenoid must be removed because of cancer, it must be reconstructed to reduce aspiration.
The procedure is performed under general endotracheal anesthesia. The patient is positioned in the supine position with the neck extended on a shoulder roll. After completion of the prepping and draping activities, a short transverse incision is made in a suprasternal skin crease to allow a tracheostomy to be accomplished between the third and the fourth tracheal ring. An endotracheal tube is placed in the tracheostoma. Removal of the endotracheal tube allows for better visualization of the vocal cords. A more superiorly placed tracheostomy is to be avoided as it may compromise the partial laryngectomy.
A transverse incision is then made in a skin crease at approximately the level of the thyroid notch. This is carried down to the strap muscles, and the skin is elevated to the hyoid bone superiorly and to the cricoid cartilage inferiorly. The strap muscles are then separated in the midline and elevated to expose the thyroid cartilage.
The external perichondrium of the thyroid cartilage is incised in the midline. A Freer elevator is used to elevate the perichondrium laterally such that it opens like a book. This requires that the periosteum be incised along both the inferior as well as the superior border of the cartilage (Fig. 23.1). The elevation should continue laterally on the side of the tumor until it is connected to the most lateral 5 mm of the thyroid cartilage. The elevation on the uninvolved side generally can be stopped after approximately 8 to 10 mm.