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Conservation Laryngeal Surgery
Key Points
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Four principles of organ-preservation surgery help provide consistent oncologic and functional outcomes: local control, accurate assessment of the three-dimensional extent of tumor, the cricoarytenoid unit as the basic functional unit of the larynx, and resection of normal tissue to achieve an expected functional outcome.
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Indirect laryngoscopy and staging operative endoscopy are critical to planning conservation laryngeal surgery. Vocal fold fixation must be distinguished from arytenoid fixation, which implies cricoarytenoid joint invasion and is a contraindication to conservation laryngeal surgery.
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The overall health of the patient must be assessed because patients must tolerate some degree of aspiration in the postoperative period. Pulmonary function tests are rarely used. Instead, if a patient is active in daily life and can walk up two flights of stairs without being winded, he or she may be a candidate for a conservation laryngeal procedure.
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Open organ-preservation options for glottic carcinomas include vertical partial laryngectomy (VPL) and supracricoid partial laryngectomy with cricohyoidoepiglottopexy (SCPL-CHEP).
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The classic VPL and its extensions all share a common approach, which includes a vertical transection through the thyroid cartilage and paraglottic space as well as a “blind” entry into the larynx through a narrow exposure.
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Functional results with VPL are variable and depend on the extent of resection and the type of reconstruction, which varies from imbrication laryngoplasty to strap muscle flap to epiglottic laryngoplasty.
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Oncologic results for VPL are excellent with T1 glottic carcinomas, but VPL should be avoided with advanced T2 lesions and all T3 and T4 glottic lesions.
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The main use for SCPL-CHEP has been in selected T2 and T3 glottic carcinomas, with local control rates greater than 90%. The SCPL-CHEP does not resect the entire supraglottis, so for transglottic tumors, the supracricoid partial laryngectomy with cricohyoidopexy (SCPL-CHP) is preferred.
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Functional results with SCPL-CHEP are predictable because of the identical resection and reconstruction in all cases. Long-term dysphagia is rare.
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Organ-preservation options for supraglottic carcinomas include the supraglottic laryngectomy and the SCPL-CHP.
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Supraglottic laryngectomy has produced excellent oncologic results for T1 and T2 supraglottic carcinomas with local control rates greater than 90%, but outcomes are extremely variable with advanced lesions.
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Voice results for supraglottic laryngectomy are typically excellent, although a certain degree of temporary dysphagia is to be expected, with more severe dysphagia expected with extended procedures.
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SCPL-CHP is indicated for supraglottic carcinomas in which the glottic level or preepiglottic space is involved, when vocal fold mobility is decreased, or with limited thyroid cartilage invasion.
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The oncologic success of the SCPL-CHP is attributed to the en bloc resection of bilateral paraglottic spaces, the preepiglottic space, and the entire thyroid cartilage.
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Contraindications to the SCPL include (1) subglottic extension greater than 10 mm anteriorly and 5 mm posteriorly; (2) arytenoid fixation; (3) massive preepiglottic space involvement with involvement of the vallecula; (4) extension to the pharyngeal wall, vallecula, base of tongue, postcricoid region, and interarytenoid region; and (5) cricoid cartilage invasion.
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Transoral robotic surgery is a new technique that offers an alternative to open and transoral laser approaches for the treatment of glottic and supraglottic carcinomas.
A variety of open surgical approaches are available. When applied for the appropriate indications, they have an excellent ability to control laryngeal cancer while conserving laryngeal function. Conservation laryngeal procedures are historically the original “organ-preservation” techniques; the first hemilaryngectomy for malignancy was performed by Billroth in 1874. Long before nonsurgical approaches were available to attempt to preserve the entire structure of the larynx, innovative surgical techniques were being used to remove enough of the larynx to allow for local control of the malignancy while preserving adequate structure to allow the larynx to function. A spectrum of laryngeal malignancies exists for which there is a complementary spectrum of conservation laryngeal procedures available. This chapter reviews the open conservation laryngeal procedures in the organ-preservation surgical paradigm available for managing the spectrum of selected glottic, transglottic, and supraglottic carcinomas. These techniques allow for the maintenance of physiologic speech and swallowing without the need for a permanent tracheostoma. The modern head and neck surgeon must have a comprehensive understanding of both surgical and nonsurgical organ-preservation strategies to allow for the most comprehensive care in the treatment of patients with laryngeal cancer.
Although the origins of conservation surgery of the larynx are more than a century old, during the second half of the past century, the conservative options were limited to vertical hemilaryngectomy and supraglottic laryngectomy. The inherent limitations of these procedures in terms of indications led to these procedures losing favor among many physicians, and experimental approaches with chemotherapy and radiation dominated the management of advanced laryngeal cancer. Then, in the last decade of the 20th century in the United States, the introduction of supracricoid partial laryngectomies (SCPLs), as well as the introduction of endoscopic laser resections, created a renaissance in surgical organ preservation for laryngeal cancer. At present, this surgical renaissance in organ-preservation surgery for laryngeal cancer has evolved into an acceptable standard of care for the 21st century.
The common thread in the history of conservation laryngeal surgery is that these procedures were first developed outside the United States and were then imported to its shores. Improvements in antibiotics and anesthetic techniques fostered the development of conservation laryngeal surgery. Vertical hemilaryngectomy, which was first described by Billroth in Germany and popularized in Europe by Leroux-Robert and Portmann, was refined in the United States by Som, Norris, and Conley. A French surgeon named Huet described a procedure in which a portion of the supraglottis was excised without the upper portion of the thyroid cartilage in 1938. Later, a Uruguayan surgeon named Alonso extended this procedure to resect the upper portion of the thyroid cartilage together with the supraglottic structures, thereby defining the supraglottic laryngectomy. The supraglottic laryngectomy was popularized in Europe by Bocca and in the United States by Ogura, Som, and Kirchner and Som. The supracricoid laryngectomies were originally described in 1959 by the Austrian surgeons Majer and Rieder approximately one decade after Alonso had described the supraglottic laryngectomy. The supracricoid laryngectomies were later promoted in Europe by Labayle and Piquet and associates and were imported to numerous institutions in the United States during the 1990s.
The first of two major classes of techniques that developed was the vertical partial laryngectomy (VPL), in which entry into the endolarynx is through a vertical thyrotomy, the most notable example of which is the vertical hemilaryngectomy. The second major class of techniques is the horizontal partial laryngectomy , in which endolaryngeal entry is made through a transverse or horizontal thyrotomy (i.e., supraglottic partial laryngectomy). During the 1960s through the 1980s, innovative surgeons reported numerous small series of patients in whom the indications and extent of resection of these basic techniques were extended in an attempt to manage larger lesions. The commonalities among these series were (1) the relatively small numbers of patients; (2) variable local control rates compared with the strict previous indications for the procedure being extended; and (3) complex reconstructions that required cartilage and mucosa rotation flaps with variable functional results. These variable results made it difficult for other surgeons to use these extended procedures in the treatment of larynx cancer. Despite these innovations of the pioneers of conservation laryngeal surgery, the techniques that most surgeons became facile with, as reflected by the large numbers of series in the literature, were the standard vertical hemilaryngectomy and standard supraglottic laryngectomy. A common surgical solution in the United States for lesions considered too large for these standard conservation laryngeal procedures was total laryngectomy, with the innovations being in the area of alaryngeal speech and speech shunt development.
In many European countries, laryngectomy, with its concomitant permanent stoma, was considered an anathema to be avoided when possible, and a different approach evolved. Majer and Rieder and Labayle and Bismuth reported on a new horizontal partial laryngectomy technique in which the entire thyroid cartilage, true cords, false cords, and all or a portion of the epiglottis and preepiglottic space were resected. The reconstruction was with a pexy either between the cricoid and hyoid (cricohyoidopexy [CHP]) or between the cricoid and the remaining epiglottis and hyoid (cricohyoidoepiglottopexy [CHEP]). This procedure, now known as the SCPL, allowed for wide and monobloc resection of the preepiglottic and paraglottic spaces and of the surrounding cartilage and soft tissue, which resulted in higher local control in glottic, supraglottic, and transglottic cancers that equaled total laryngectomy and resulted in speech and swallowing without a permanent tracheostomy. Unlike the plethora of extensions of the VPL and the supraglottic laryngectomy, the SPCLs were repeated in many patients by numerous European centers during the 1970s through to the 1990s, with consistently excellent local control and functional results.
Conservation Laryngeal Surgery Today
Although conservation surgery of the larynx had its origins in the 19th century, the standard of care in the 21st century dictates that when VPL, supraglottic laryngectomy, or SCPL is an alternative for a given patient, the options should be discussed with the patient. In most cases, it is the general otolaryngologist–head and neck surgeon who makes the diagnosis of laryngeal cancer, and therefore these are frequently the physicians who first counsel patients concerning their treatment options. Standard of care dictates that a discussion based on the literature be had with the patient concerning both surgical and nonsurgical approaches to organ preservation. In our opinion, one scenario might be that physicians rationalize that because they do not do these procedures, the patient should be sent to the radiation therapist; however, this may not be in the best interest of the patient. Alternatively, in our opinion, the physician who diagnoses a laryngeal cancer who does not have the expertise to offer all surgical and nonsurgical options could refer the patient to a multidisciplinary center that can triage patients to either surgery or nonsurgery on the basis of the needs and desires of the patient.
An analogy can be made with free tissue reconstruction surgery. If a patient has a large jaw carcinoma, and the superior option from the oncologic and functional perspective is a free flap, we would not offer the patient a lesser surgical procedure or chemotherapy and radiation. The patient would be sent to a surgeon with a special expertise in free flap surgery. This is possible because, in the past 20 years, a cadre of head and neck subspecialists have cropped up who have a particular interest and expertise in performing free flap surgery. In fact, over the past decade, we have witnessed a similar phenomenon in the United States in the area of organ-preservation surgery for laryngeal cancer. In our opinion, a similar situation exists in which some head and neck surgeons have special expertise in open and endoscopic approaches for laryngeal organ preservation in the face of laryngeal cancer.
The focus of this chapter is to provide the general otolaryngologist–head and neck surgeon with an introduction to these techniques. This information is important because it is the responsibility of the general otolaryngologist–head and neck surgeon to understand the indications for the full spectrum of open and endoscopic organ-preservation surgical approaches and either gain the expertise to perform these procedures or refer the patient to surgeons who have this special expertise.
During the 1970s and 1980s, the functional and oncologic results after supraglottic laryngectomy were reported in numerous series in the United States, defining the role of this technique among the plethora of surgical and nonsurgical options available for supraglottic carcinoma. During the same period and into the 1990s, the role of VPL for glottic carcinoma has been reexamined because of advances in nonsurgical and laser endoscopic approaches to similarly staged disease. In the 1990s, the SCPL was imported to numerous institutions in the United States, and the European functional results have been reproduced. SCPLs have broadened the spectrum of reliable techniques available to the conservation laryngeal surgeon.
At present, a renaissance is occurring in the United States in the area of conservation laryngeal surgery. Many factors have fostered the rekindled interest in conservation laryngeal surgery, including (1) a clearer understanding of the three-dimensional (3D) extent of laryngeal carcinoma, which has stemmed from numerous clinicopathologic studies and from advances in radiologic techniques; (2) numerous long-term studies of outcome after the application of a broad spectrum of techniques; and (3) the introduction of new techniques during the past two decades. Today, a variety of techniques are available for selected laryngeal malignancies, with predictable functional and oncologic outcome based on analyses in the literature of many patients. The full spectrum of surgical techniques allows the surgeon to consistently offer patients with selected lesions excellent local control that will result in speech and swallowing without the need for a permanent tracheostoma. This may provide the patient with an alternative to nonsurgical organ-preservation modalities. Organ-preservation principles have been established to which the surgeon must adhere to maximize both oncologic and functional outcome. Conservation laryngeal surgery is precision surgery, and to achieve successful oncologic and functional results, the conservation laryngeal surgeon should have a firm grasp on the clinical assessment of laryngeal cancer and a complete understanding of the surgical techniques. The art of correctly staging the lesion as one appropriate for a conservation laryngeal procedure requires an in-depth knowledge of both the static and dynamic anatomy of the larynx and how the tumor relates to it.
Anatomy, Physiology, and Tumor Spread
In 1966, Bocca elegantly stated, “Often cancer seems to have limits, while the surgeon seems to have none. We should make efforts to force upon our knife the same limits as those which surrounding tissues or structures force upon cancer and its spread.” Bocca's eloquent statement underscores that successful outcome in conservation laryngeal surgery is predicated on a thorough knowledge of the pertinent surgical anatomy and on an understanding of the behavior of the malignancy in a particular anatomic site. Much of what is known concerning the 3D spread of malignancy through the larynx has been derived from clinicopathologic studies in which the entire larynx was sectioned. These whole-organ section studies form the basic scientific foundation for clinicians who perform conservation laryngeal surgery.
The surgical anatomy of the larynx can be understood in terms of the skeleton and connective tissue barriers, the spaces delineated by these structures, and the soft tissue structures that include the fat, musculature, vessels, nerves, and adnexa that fill these spaces. The skeleton of the larynx ( Fig. 108.1 ) is dominated by the thyroid cartilage, which articulates posteriorly and inferiorly through the inferior cornua with synovial joints on the posterolateral aspects of the cricoid cartilage. A thick tendon originates from the superior cornua and attaches to the lateral most aspect of the “crown” of the larynx, the hyoid bone. Anteriorly is a notch, and the lateral aspect of the laminae is traversed by the oblique line, which is the point of attachment of the strap musculature. The extension of cancer into the thyroid cartilage tends to occur in areas of ossification of the cartilage. The mode of invasion into the ossified bone has been attributed to osteoclast formation and extension along collagen bundles, or through areas of high vascularity. The most common site of invasion of the thyroid cartilage was at the angle, although other sites of predilection for carcinoma invasion are the points of attachment of the cricothyroid membrane and the anterior origin of the thyroarytenoid musculature. The perichondrium provides an excellent barrier to invasion, and once the carcinoma is within the cartilage, the cancer can extend throughout the cartilage behind an intact perichondrium, which precludes surgical cuts through the cartilage, as is done in some partial laryngectomies. Nakayama and Brandenburg noted that a large proportion of patients staged clinically as T3 actually had thyroid cartilage invasion when the specimens were analyzed by whole-organ sectioning, and they noted that in these patients with T3 glottic cancers, any combination of two factors—including a significant degree of calcification of the cartilage, tumor length greater than 2 cm, and anterior commissure involvement—resulted in a higher incidence of cartilage invasion (71% to 92%).
The cricoid cartilage is the only circumferential ring in the airway, and preservation or reconstruction of its ring-shaped structure allows for decannulation after conservation laryngeal surgery. The arytenoid cartilages sit atop the cricoid, to which they are attached by a synovial joint. The two muscular processes of the arytenoid cartilages are oriented posteriorly and laterally, and the vocal cord tendon originates from the tip of the vocal process and spans anteriorly to the thyroid cartilage. The most common site of cricoid cartilage invasion by carcinoma is at its posterior superior border, and the most common site of arytenoid invasion is at the points of attachment of the joint capsule.
The epiglottis, with its numerous fenestrations, originates from the tendinous attachment on the thyroid cartilage and fans out from its most inferior point, known as the petiole , to a widened superior aspect above the hyoid. The carcinoma on the infrahyoid surface of the epiglottis readily extends through the fenestrations of the epiglottic cartilage through blood vessels and the ducts of the seromucinous glands. The hyoid bone is almost never involved by supraglottic carcinoma. Kirchner noted no cases of hyoid bone invasion in 55 supraglottic carcinomas evaluated by whole-organ section, although in Kirchner's series, two patients had cancer up to the periosteum, one of which could be palpated at the level of the thyrohyoid membrane, and one had vallecular mucosal involvement. Among 172 patients with supraglottic carcinoma reported by Timon and colleagues, only four patients had hyoid bone invasion, and a common feature of all of these patients was vallecular mucosal involvement. Preservation of the hyoid bone helps with swallowing postoperatively. Understanding this concept is essential and makes it possible to perform SCPL with CHP in selected transglottic tumors. These authors concluded that it is sound to preserve the hyoid bone in cases without palpable submucosal vallecula carcinoma or vallecular mucosal involvement.
Numerous condensations of fibrous tissue traverse the 3D anatomy of the larynx. Some of the modern knowledge of these structures comes from the pioneering work of Tucker, Kirchner, and Smith, who studied whole-organ sections of larynges and analyzed this anatomy. The conus elasticus ( Fig. 108.2 ) spans from each vocal cord down laterally to the cricoid cartilage. The conus elasticus provides a temporary barrier for the spread of early glottic carcinoma but, ultimately, for larger cancers, it serves as the gateway to the subglottic and extralaryngeal spread of carcinoma. Posteriorly, the conus elasticus is also attached to the arytenoid, and it provides stability to the arytenoid and the vocal tendon. The vocal tendon, which essentially is a medial condensation of the conus elasticus, attaches anteriorly to the thyroid cartilage at the Broyles ligament or the anterior commissure tendon. Although the anterior commissure tendon is devoid of perichondrium, the ligament constitutes a dense fibrous attachment to the cartilage and sends slips of fibrous tissue superiorly to the thyroepiglottic ligament. Kirchner and Carter have noted that the anterior commissure tendon is a point of dense adhesion of fibrous tissue, and it is rare for an early glottic cancer with anterior commissure involvement to erode into the thyroid cartilage here; however, the anterior commissure tendon provides access to cartilage invasion for larger cancers, which spread superiorly or inferiorly. Anteriorly, a superior inferior condensation of the conus elasticus, called the cricothyroid ligament , is a central structure that does not spread out laterally to provide a connective tissue barrier along the circumference of the cricoid. This is different than its superior counterpart, the thyrohyoid membrane, which drapes along the entire circumference of the thyroid cartilage superiorly and spreads upward to the hyoid bone ( Fig. 108.3 ). Extension out of the larynx through the thyrohyoid membrane alone is rare and is typically seen when cancer exits the larynx through the upper portion of the thyroid cartilage. The quadrangular membrane ( Fig. 108.4 ) originates from the top of the arytenoid posteriorly and from the lateral aspect of the epiglottis anteriorly and then extends inferiorly like a curtain to an inferior condensation of fibrous tissue, which spans between the inferior aspect of the arytenoid posteriorly and the petiole of the epiglottis anteriorly. The hyoepiglottic ligament was elegantly described by Zeitels and Kirchner, who showed this structure to be a resilient barrier to malignant spread from the supraglottis to the tongue base when the cancer is confined to the laryngeal membranes and does not clinically invade the suprahyoid epiglottis.
The skeleton and fibrous tissue barriers demarcate a number of spaces within the larynx. The superior most space is the preepiglottic space ( Fig. 108.5 ), which is filled with fat and traversed by blood and lymphatic vessels. Kirchner and Carter noted that carcinoma tends to invade within the preepiglottic space with a “pushing edge,” which is almost encapsulated after it reaches the elastic tissue membranes in the preepiglottic space, which contributes to the oncologic safety in saving the hyoid bone during supraglottic surgery. The boundaries of this space are the vallecular mucosa and the hyoid superiorly, the thyrohyoid membrane and the thyroid cartilage anteriorly, and the epiglottis posteriorly. Posterolaterally, on either side, the preepiglottic space is bounded by the superior portions of the paraglottic space.
A paraglottic space is found on either side of the larynx ( Fig. 108.6 ). Superiorly, the medial boundary is the quadrangular membrane, whereas inferiorly, the medial margin is the conus elasticus. It originates superiorly within the aryepiglottic fold, where it fades to a peak. The paraglottic space makes up the substance of the true and false cords, and within it are the thyroarytenoid musculature and the mucosa-lined, air-filled space known as the ventricle and its superior extension, the saccule. Inferiorly, it follows the conus elasticus down to the top of the cricoid cartilage; anteriorly, it abuts the preepiglottic space and the anterior third of the thyroid cartilage; and the posterolateral boundary is the mucosa of the medial aspect of the piriform sinus. The paraglottic space traverses the supraglottis, glottis, and subglottis laterally within the larynx. Rather than having a distinct barrier to superior-inferior spread, cancer seems to be impeded in its course through the paraglottic space to varying degrees by the hourglass shape of the space, which is made by the indentation of the ventricle and saccule. One additional space is the Reinke space, which actually is a potential space under the true vocal cord mucosa that provides no barrier to invasion.
The behavior of carcinoma in the supraglottis is modified by the soft tissue, connective tissue barriers, and the skeleton of the larynx ( Fig. 108.7 ). In an analysis of whole-organ sections, Kirchner showed that supraglottic carcinomas that overlie the epiglottic cartilage have a tendency (9 of 10 cases) to extend into the preepiglottic space, at least microscopically, through the fenestrations in the epiglottic cartilage. In addition, working with the whole-organ section collection at Johns Hopkins, Bridger and Nassar showed that seromucinous tubuloalveolar glands extend through the fenestrations and provide a route of spread of cancer into the preepiglottic space. Although it had been suggested in the past that embryologic fusion planes somehow provide protection against inferior spread of carcinoma from the supraglottis to the glottis, a study that evaluated all of the series of whole-organ sections in the literature revealed that the incidence of spread of supraglottic carcinoma to the glottic level is between 20% and 54%. This study indicated a statistically significant relationship between the presence of abnormal cord mobility or involvement of carcinoma below the false cord and glottic level extension, most commonly through the paraglottic space.
Carcinomas at the glottic level tend to begin at the junction of the anterior one third and posterior two thirds of the vocal cord. They readily pass through the Reinke space to the tissues below. Early studies with submucosally injected dyes and radioisotopes by Pressman indicated that barriers exist between the two sides of the glottis and the supraglottis. Welsh and colleagues demonstrated that as dye concentration increases, these barriers become less effective. For early lesions, the conus elasticus provides a barrier to extension; as the lesion enlarges, this barrier becomes less pertinent.
The sensation to the supraglottis is supplied by the superior laryngeal nerves, whereas the glottis and subglottis are innervated by the recurrent laryngeal nerve. The neural structures play an important role in timely postoperative functional rehabilitation. When possible, the main trunks of the superior and recurrent laryngeal nerves and the hypoglossal nerves bilaterally should be preserved during conservation laryngeal surgery.
Certain aspects of physiology of the larynx are pertinent to successful application of conservation laryngeal surgery. Hirano and colleagues, in a whole-organ analysis of the normal larynx, noted that 50% to 65% of the entire adult airway is located posterior to the tips of the vocal processes and they concluded that the posterior larynx is the respiratory airway and the anterior portion is the phonatory airway. This is because all of the musculature that opens and closes the glottic chink (the lateral cricoarytenoid musculature) changes the position of the vocal processes during speech and swallowing. The arytenoids are responsible for opening the airway for breathing and closing it during swallowing and speaking, and the vocal cords provide vocal quality during phonation; therefore loss of one or both vocal cords results in hoarseness, but preservation of at least one arytenoid and an intact circumferential ring at the level of the cricoid is sufficient for speech and swallowing without a tracheostomy.
Principles of Organ-Preservation Surgery
The otolaryngologist–head and neck surgeon must adhere to certain key principles to determine a patient's eligibility for conservation laryngeal surgery. The advent of the SCPL makes us direct our focus away from the vocal fold and concentrate on the cricoarytenoid unit as the essential functional unit of the larynx. The organ-preservation principles are formulated to help provide consistent oncologic and functional outcomes. These can then be compared with current nonsurgical organ-preservation options to allow the patient and physician to make educated decisions regarding treatment. Adopting these principles will enable the surgeon to maximize oncologic and functional outcomes for a number of glottic, supraglottic, and transglottic malignancies.
First Principle: Local Control
Local control is the most important principle. Survival from the index cancer is compromised if a local failure results after radiation therapy or surgery to the supraglottis and glottis. Early detection of the primary site recurrence may be difficult for a number of reasons. Medical and surgical organ-preservation modalities alter the topography of the larynx and make definitive evaluation of recurrent cancer difficult. Symptoms may be attributed to the treatment intervention or recurrent tumor, although increasing pain, persistent ear pain, and dysphagia are ominous signs. Repeat endoscopy and biopsy of the original primary site are warranted. Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) may also be helpful to explain recurrent or persistent cancer. Organ-preservation laryngeal procedures should be used only when resection of the tumor can be accomplished comfortably with local control rates that approximate those of total laryngectomy.
Second Principle: Accurate Assessment of the Three-Dimensional Extent of Tumor
The second principle of organ-preservation surgery is to be able to confidently predict the extent of tumor. A comprehensive appreciation of laryngeal anatomy and function is necessary. The inability to accurately predict the extent of tumor in a conservation laryngeal procedure may lead to total laryngectomy when another organ-sparing approach may have been possible.
Third Principle: The Cricoarytenoid Unit Is the Basic Functional Unit of the Larynx
The cricoarytenoid unit is the basic functional unit of the larynx and consists of an arytenoid cartilage, cricoid cartilage, associated musculature, and superior and recurrent laryngeal nerves for that unit. Preservation of at least one functional cricoarytenoid unit makes it possible to consider an organ-preservation procedure. This is a foreign concept to most surgeons who perform VPL and supraglottic laryngectomy. Along with the tumor (T)-staging system for laryngeal cancer, surgeons focus on the vocal fold rather than on the cricoarytenoid unit. The paradigm shift from the vocal fold to the cricoarytenoid unit is essential for the head and neck surgeon to be able to use the full spectrum of organ-preservation surgeries. It is the cricoarytenoid unit, not the vocal folds, that allows for physiologic speech and swallowing without the permanent need for a tracheostoma after SCPL.
Fourth Principle: Resection of Normal Tissue to Achieve an Expected Functional Outcome
This principle may seem counterintuitive because we are talking about “conservation” laryngeal surgery. What we are conserving is the function of the larynx, not necessarily all the regions of the larynx that are uninvolved with cancer. This resection of normal tissue is necessary to achieve consistent functional outcomes in terms of speech and swallowing. A reliable reconstruction for each organ-preservation surgical choice that is proven with regard to speech and swallowing outcome should make the surgeon feel more at ease when comparing nonsurgical and surgical organ-preservation results for a patient. Reconstructions based on the extent of tumor resection for clear margins alone often result in novel reconstructions and the surgeon's trepidation regarding functional outcome. A better approach is to perform a standard resection in which a consistent functional outcome is known.
Preoperative Evaluation
The preoperative evaluation includes an oncologic assessment of the primary site, regional nodes, and distant sites. In addition, it includes an assessment of the patient's ability to medically undergo the surgery and postoperative treatment. Finally, patient and family insight, emotional state, and ability and willingness to undergo the postoperative rehabilitation should be considered.
Clinical Evaluation of the Primary Site
Before examining the larynx, the physician should listen to the patient speak and breathe. The degree of airway impairment and the voice quality should be assessed. Glottic carcinomas that affect the phonatory structures tend to cause hoarseness; supraglottic cancers are frequently above the cords and cause a muffled “hot potato” voice as they enlarge. Hoarseness from a supraglottic carcinoma may indicate impairment of cord mobility as a result of arytenoid involvement or glottic level involvement. Next, both sides of the neck should be palpated for nodal disease; the thyroid cartilage should be palpated for irregularities, as should the areas directly above and below the thyroid cartilage. A bulge or mass at the level of the thyrohyoid membrane may indicate massive preepiglottic space invasion. A mass at the level of the cricothyroid ligament may indicate a delphian lymph node, which indicates subglottic extension of the malignancy. Indirect mirror or fiberoptic laryngoscopy is used to assess the larynx and surrounding structures. The important gross pathologic characteristics that need to be evaluated are airway impairment, endophytic versus exophytic disease, superficial spread versus deep invasion, mucosal structures involved, arytenoid and vocal cord mobility, and extensions out of the endolarynx.
The clinical assessment of laryngeal mobilities provides excellent insight into the 3D extension of carcinoma within the larynx. Mobility of the vocal cord itself, without attention to arytenoid mobility, is adequate when planning for management directed to the entire organ, such as total laryngectomy or radiotherapy. Biller and Lawson and Ogura's team have noted that assessment of arytenoid mobility and cord mobility is important in the preoperative planning for conservation laryngeal surgery, particularly when the vocal cord itself is fixed. Vocal cord mobility is best clinically assessed during indirect laryngoscopy by having the patient speak or breathe deeply, whereas arytenoid mobility is best assessed by having the patient cough gently.
Cancers that involve the glottis and supraglottis have different effects on vocal cord mobility and arytenoid mobility. Impaired mobility from glottic carcinoma may be a result of superficial thyroarytenoid invasion or bulk on the surface of the cord in an exophytic lesion. Hirano and others assessed the degree of thyroarytenoid muscle invasion in glottic carcinoma and found fixed cords had deeper invasion into the musculature than impaired cords. Numerous studies have demonstrated that glottic carcinoma associated with a fixed vocal cord most commonly results from extensive invasion of the thyroarytenoid muscle. In some patients, subglottic extension with fixation to the cricoid cartilage and lateral extension with adherence to the thyroid cartilage resulted in fixation of the cord and invasion of the lateral cricoarytenoid musculature and the cricoarytenoid joint. At the supraglottic level, cancer invasion into the thyroarytenoid musculature at the glottic level is less likely; the most common cause of cord fixation, noted by Hirano and others, was deep arytenoid cartilage invasion superiorly. Montgomery and Iwai assessed vocal cord and arytenoid mobility independently in preparation for conservation laryngeal surgery of the supraglottis. In a whole-organ section series, Brasnu and colleagues noted two types of impairment in arytenoid mobility—pseudofixation and actual fixation. The “weight impact” of the tumor, in which the arytenoid motion seems impaired superiorly, causes a pseudofixation. Actual fixation results from the malignant involvement of the intrinsic laryngeal musculature or the cricoarytenoid joint, or both ( Fig. 108.8 ). These impairments are distinguished by careful evaluation of the vocal fold; if any motion of the cord is noted in the presence of what seems to be arytenoid fixation from a supraglottic cancer, this is pseudofixation. This information is valuable to the conservation laryngeal surgeon, because it is unlikely that a larynx with a pseudofixed arytenoid has the cricoarytenoid joint and musculature involved, whereas these areas are involved in more than two thirds of patients when true fixation of the arytenoid is present. We have found that the fiberoptic scope is useful in the assessment of vocal cord mobility in the presence of exophytic supraglottic carcinomas because the tip of the scope can be manipulated past the lesion to look at the structures below. The clinical implication is that careful assessment of vocal cord and arytenoid mobility is essential when planning for conservation laryngeal surgery to attempt to understand which deep structures are invaded and which, in turn, may improve the likelihood of applying the appropriate surgical technique.
The final aspect of the physical examination of the primary site is performed during direct laryngoscopy with general anesthesia. Direct laryngoscopy allows for biopsy of the lesion to be obtained, and it allows for a thorough visual evaluation of the larynx and surrounding structures with the routine use of the operating microscope or rigid endoscopes. Palpation of the lesion and surrounding structures with endoscopic instrumentation can yield valuable information concerning submucosal extent of disease. Palpation of the vallecula with a finger and palpation of the posterior floor of the mouth provide a critical assessment of submucosal extent of disease from supraglottic carcinoma in these areas.
After this clinical assessment, the conservation laryngeal surgeon should have a clear understanding of the extent of the lesion and should have in mind which surgical or nonsurgical options are optimal for the patient.
Radiologic Evaluation of the Primary Site
Although imaging studies are frequently available before the clinical evaluation of the primary site, the best role of these studies is to corroborate the clinical findings noted on indirect and direct laryngoscopy and to corroborate clinical evidence of deep growth of lesions. This is because, although specific findings are particularly useful to assess with imaging studies, there are limitations to the value of these studies, and they may either overpredict or underpredict tumor in certain situations. One caveat is that when evaluating particularly small lesions or the superficial extension of a large lesion, CT or MRI may demonstrate little abnormality. This is because these modalities are insensitive to superficial mucosal masses. Another pitfall is seen in those with large exophytic lesions. When lesions have large extensions into the airway, they may sit up against adjacent mucosal sites, such as the piriform sinus, tongue base, floor of the mouth, lateral pharyngeal wall, or ventricle or saccule. Although the point of the attachment of the cancer may be small and discrete, the scan may deceptively indicate that all mucosal surfaces are involved. In these patients, the endoscopist has a better view of the lesion, and the clinical examination takes precedence over the radiologic evaluation. It may be useful to perform the Valsalva maneuver during the CT scan if these issues cannot be resolved at endoscopy. Occasionally, tumors may be isodense (on CT) or isointense (on MRI) with the surrounding tissues, resulting in overestimation or underestimation of the size of the lesion noted on the clinical examination. In these patients, the radiologist and surgeon should work together to find the true extent of tumor.
Laryngeal imaging studies have been useful in a number of areas. Occasionally, the bulk of the lesion extends submucosally into the subglottis. In these patients, MRI more so than CT can be useful to demonstrate the direct invasion or secondary thickening or asymmetry caused by the lesion in this area. Coronal T1-weighted MRI scans are particularly elegant in demonstrating submucosal transglottic spread. The cricoarytenoid area is best evaluated with axial scans, and sclerotic changes on CT are indications of perichondrial or direct arytenoid cartilage involvement. Sagittal MRI has been shown to be a sensitive and specific imaging modality for varying degrees of preepiglottic space invasion. Because the cartilages of the larynx calcify, starting in the second decade in an inhomogeneous fashion, loss of calcification of the cartilage on CT is an unreliable indicator of tumor extension. MRI has been shown to be highly sensitive for cartilage invasion, particularly if fat-suppressed gadolinium-enhanced scans are performed. Fat-suppressed gadolinium-enhanced scans are highly sensitive for cartilage invasion, but their specificity is reduced because inflammation and chondronecrosis will show similar findings. Kirchner noted that the most common site of thyroid ala invasion from glottic carcinoma is the lower edge, and questionable isolated involvement of the superior aspect of the thyroid cartilage may represent random calcification patterns within the cartilage. We agree with Kikinis and colleagues that MRI has been more useful for evaluating tumor extension into or through laryngeal cartilages. Fluorodeoxyglucose PET has gained popularity among physicians in the staging and surveillance of head and neck cancer. Its most promising role in larynx cancer appears to be in the delineation of treatment effect (medical organ-preservation strategies) from recurrent tumor.
Tumor Stage
The larynx by convention is divided into three discrete parts for the purpose of T staging. The supraglottis begins inferiorly at the lateral angle of the ventricle. Although the supraglottis extends superiorly up to the tip of the epiglottis, the vallecular mucosa is part of the oropharynx. The glottis begins at the lateral angle of the ventricle, and it extends 1 cm inferiorly at the midcord level. The subglottis begins at the inferior aspect of the glottic level and extends to the inferior aspect of the cricoid cartilage. Although this partitioning of the larynx is somewhat artificial, it allows for a staging system that, despite its shortcomings, allows for comparison of treatment modalities and prognostication. Although the T-staging system is useful when comparing modalities that encompass the entire larynx, such as radiotherapy or total laryngectomy, it lacks the precision necessary to determine whether conservation laryngeal surgery may be performed at all and, if so, which particular procedure is indicated. Within each of the four T stages, there is a spectrum of lesions at each site for which a variety of conservation laryngeal procedures may be used with successful outcome.
When planning for conservation laryngeal surgery, numerous factors that go beyond the level of detail required in the T-staging system should be evaluated. Clinically important factors include the precise extent of mucosal involvement, the depth of invasion of the malignancy, and the vocal cord and arytenoid mobilities. Although it has frequently been stated that millimeter margins are adequate for conservation laryngeal surgery, the caveat to this axiom is that for any given conservation laryngeal technique, millimeters of tumor extension within the larynx may preclude performing that technique and may result in intraoperative conversion to total laryngectomy. The conservation laryngeal surgeon should describe the lesion in more detail than the T-staging system to allow for application of the appropriate conservative laryngeal technique.
Overall Clinical Assessment
The primary medical issues important to the conservation laryngeal surgeon are the patient's ability to successfully tolerate the general anesthesia required to perform the procedure, the patient's lack of severe systemic medical problems that may dramatically impair wound healing, and the patient's pulmonary reserve to tolerate the postoperative course. The standard criteria are available for assessing anesthesia-related risks before surgery and should be used. Systemic illnesses that may predispose to poor wound healing include severe nutritional depletion, medications associated with organ transplantation, diabetes mellitus, and gastroesophageal reflux.
The degree to which the severity of pulmonary disease is used in the decision to proceed with conservation laryngeal surgery remains controversial in the literature. The real question is how well the patient will tolerate some degree of aspiration during the early postoperative period. The amount of postoperative aspiration varies with the type of surgery contemplated. Vertical hemilaryngectomy that spares the arytenoid typically causes little impact on swallowing function, whereas extensions of standard or extended supraglottic laryngectomy may result in increased dysphagia and aspiration risk. Some authors advocate pulmonary function tests routinely for all patients, whereas others use clinical evaluation such as walking up two flights of stairs without getting short of breath. The percutaneous gastrostomy tube has been useful for patients who require long periods of no nutrition by mouth. The literature actually leaves a fair amount of leeway for the clinician in terms of the pulmonary workup and in terms of how to use this information in clinical decision making. We rarely use pulmonary function testing preoperatively unless requested by a medical consultant or anesthesiologist in preparation for a general anesthetic. If the patient has chronic obstructive lung disease but can walk up two flights of stairs without being winded and is active in his or her daily life, the risks, benefits, and alternatives of conservation laryngeal surgery are discussed with the patient. If the pulmonary status indicates severe impairment of activity and a likelihood of morbidity or mortality after the procedure, we do not recommend conservation laryngeal surgery for that patient. In actual practice, each surgeon should know, over time, the limitations of a particular surgical technique in their hands . With this approach, only the rare patient will need functional laryngectomy for intractable aspiration, although many patients will have also had their larynges spared with conservation laryngeal surgery.
An important factor in patient selection is the patient's insight into the problem and the ability of the patient to play an active role in his or her rehabilitation. The issue of age has been discussed often in the literature, and some authors have strict age criteria for performing partial laryngeal surgery. Others have stated that it is the patient's biologic age and overall constitution that are more important than the chronologic age. In addition, conservation laryngeal surgery is a team endeavor, and if the patient and family prefer to “sit on the sidelines” rather than be actively involved in the rehabilitation process, it is our experience that the patient will likely have a protracted course with increased morbidity. In our institutions, the assessment of the patient's willingness and ability to be rehabilitated is a joint decision among the speech pathologist, otolaryngologist, patient, and family. Although we do not obtain a preoperative modified barium swallow study, all patients are assessed by a speech pathologist, and the rehabilitation is discussed with the patient. The sine qua non for a cooperative and functional patient postoperatively is extensive preoperative counseling by the surgeon and speech pathologist. The patient and family should understand that much work is required on their part for rehabilitation. Some patients may choose alternative nonsurgical approaches to their problem or even total laryngectomy to avoid the swallowing rehabilitation required for some conservation laryngeal procedures.
The literature is replete with nonsurgical strategies for the preservation of the larynx for all stages of laryngeal carcinoma. All surgical and nonsurgical therapies have expected sequelae, risks, and complications, which are balanced by the ability of a given technique to control the malignancy. The two central issues of great importance to the patient, his or her family, and the physician are (1) quality of life and (2) cancer control. The clinician weighs each factor carefully before advising a patient on which modality is preferred in a particular case. It is tempting for clinicians to apply their value system to what is good for a patient, although when making recommendations, the clinician has ethical and legal responsibilities to describe to patients the risks and benefits of, and the alternatives to, the variety of treatment options available for their cancer.
Surgical Techniques
The next section reviews the various conservation laryngeal techniques available for the management of the spectrum of laryngeal carcinomas. The discussion is limited to open surgical approaches in which the functional goal is speech and swallowing without a permanent tracheostomy. Several alternative treatment options often exist for a given laryngeal cancer, including endoscopic surgical approaches or nonsurgical therapy. These approaches are reviewed in other chapters of this textbook, which the reader should refer to for comparison. Although the discussion here will focus on the open surgical approaches, in reality these options do not exist in a vacuum but are always considered in relation to other alternative approaches. The clinician should have a thorough understanding of endoscopic surgery, radiation therapy, and open organ-preservation surgery to develop a comprehensive approach to laryngeal cancer. The main category of surgical technique is introduced with a review of the literature that analyzes the oncologic results, basic surgical technique, key surgical points, extensions of the procedure, expected functional outcome, and complications.
Indications and Contraindications
The indications for particular surgical techniques presented in the literature have varied over time depending on the stage of development of the technique. When a technique is first introduced, most surgeons advocate conservatism in its application. Later, pioneering surgeons attempt to cautiously extend the use of techniques, frequently on the basis of applications of their surgical skills combined with their knowledge of surgical anatomy and, by necessity, without the benefit of long-term oncologic follow-up evaluation. The final stage in the development of a technique, according to Daly, is reevaluation followed by acceptance of the technique on the basis of reported results. Before the last stage of development, the indications for a particular technique are usually parochial and are based on the anecdotal experiences at a particular institution or the pronouncement of a pundit in the field. Reliance on the literature for indications and contraindications is, therefore, frequently not helpful because surgeons usually attempt to use techniques for a large spectrum of tumor stages. To address this problem, we have provided, for each technique, a thorough literature review in terms of oncologic results, functional outcome, and complications. The surgeon can use this information when advising patients concerning the risks, benefits, and alternatives for a particular surgical procedure.
Conservation Laryngeal Surgery for Lesions That Originate in the Glottic Level
Vertical Partial Laryngectomies
All VPLs share a common approach, which includes a vertical transection through the thyroid cartilage and paraglottic space. The extent of resection is decided on the basis of the preoperative and intraoperative assessment of the tumor extent. Although this vertical approach provides useful and expeditious access to the endolarynx, they all share a common characteristic: “blind” entry into the larynx through a narrow exposure. Depending on the extent of the primary lesion, the initial vertical cut may be close to or distant from the cancer. This point should be considered when these procedures are used.
Vertical Hemilaryngectomy
Oncologic Results
Among the series in the English-language literature, in which local control has been reported in terms of the T stage, the local recurrence rates for T1 lesions ranged from 4% to 11%, and six of seven series had a local control rate of greater than 90% ( Table 108.1 ). In one large series of 248 patients, the local control was 93% (104 of 112) for patients with malignancy confined to the true cords without anterior commissure involvement. In that same series, patients with anterior commissure involvement without impaired mobility or extension beyond the glottis had a local failure rate of 25% (8 of 32). When the anterior commissure is involved, the most common site of recurrence is the subglottis, as demonstrated in a series in which 14% of patients (8 of 58) with anterior commissure involvement had vertical hemilaryngectomy failure; in 7 of 8 of these patients, the recurrence was in the subglottis. When the anterior commissure is involved by cancer, a wide surgical margin is indicated in the subglottis. Another factor that portends poor local control is extension beyond the confines of the glottis or impaired mobility.
TABLE 108.1
Local Recurrence After Vertical Hemilaryngectomy for T1 Glottic Carcinoma
| Reference | Year | T1 ( n ) | LR (%) |
|---|---|---|---|
| Mohr et al. | 1983 | 25 | 2 (8) |
| Liu et al. | 1986 | 24 | 1 (4) |
| Rothfield et al. | 1989 | 54 | 2 (4) |
| Laccourreye et al. | 1991 | 146 | 16 (11) |
| Thomas et al. | 1994 | 94 | 8 (9) |
| Apostolopoulos et al. | 2002 | 28 | 2 (7) |
| Brumund et al. | 2005 | 232 | 20 (9) |
LR, Local recurrence.
Mohr and others reported the highest local control in the literature for T2 glottic carcinoma after extended vertical hemilaryngectomy, but they included only T2 lesions with impaired mobility and excluded lesions that extended beyond the midventricle (only five patients) or beyond 5 mm into the subglottis because of the known high local failure rate for these lesions. Subglottic extension has been associated with cricoid cartilage invasion, which is not resected in the standard vertical hemilaryngectomy. Extension into the supraglottis through the ventricle should alert the surgeon to the possibility of thyroid cartilage invasion, which may account for the higher local recurrence in this patient group. The difficulty in managing T2 glottic carcinoma with vertical hemilaryngectomy was noted in a number of series that had local failure greater than 20%, and 8 of the 10 series in the English-language literature that correlated local recurrence with T stage reported a local recurrence rate of greater than 14% ( Table 108.2 ). One cause for impaired cord mobility is varying degrees of thyroarytenoid muscle invasion within the paraglottic space, which, in our opinion, may account for the higher local failure rates in vertical hemilaryngectomy, in which the paraglottic space is routinely transected. In a comparison of 204 T2N0 glottic carcinomas treated with vertical hemilaryngectomy versus SCPL, the 10-year actuarial local control was 69% versus 95%, and the 10-year overall survival was 46% versus 66%, respectively; this demonstrates the oncologic advantage of the SCPL resection for T2 glottic carcinomas.
TABLE 108.2
Recurrence After Vertical Hemilaryngectomy for T2 Glottic Carcinoma
| Reference | Year | T2 ( n ) | LR (%) |
|---|---|---|---|
| Bailey and Calcaterra | 1971 | 18 | 3 (17) |
| Biller et al. | 1971 | 58 | 3 (5) |
| Kirchner and Som | 1975 | 58 | 8 (14) |
| Som | 1975 | 104 | 25 (24) |
| Mohr et al. | 1983 | 27 | 1 (4) |
| Liu et al. | 1986 | 14 | 2 (14) |
| Laccourreye et al. | 1991 | 102 | 26 (26) |
| Johnson et al. | 1993 | 31 | 7 (23) |
| Apostolopoulos et al. | 2002 | 14 | 2 (14) |
| Brumund et al. | 2005 | 35 | 12 (31) |
LR, Local recurrence.
The local control after the management of T3 glottic carcinoma with VPL has yielded variable local failure rates that range from 11% to 46%, and four of the six series reported local failure rates greater than 36% ( Table 108.3 ). This finding may be related to the fact that many cases may be understaged and may have thyroid cartilage invasion, which is routinely partially resected during vertical hemilaryngectomy.
TABLE 108.3
Local Recurrence After Vertical Hemilaryngectomy for T3 Glottic Carcinoma
| Reference | Year | T3 ( n ) | LR (%) |
|---|---|---|---|
| Kirchner and Som | 1971 | 22 | 9 (41) |
| Som | 1975 | 26 | 11 (42) |
| Lesinski et al. | 1976 | 18 | 3 (17) |
| Mendenhall et al. | 1984 | 13 | 6 (46) |
| Biller and Lawson | 1986 | 11 | 4 (36) |
| Kessler et al. | 1987 | 27 | 3 (11) |
LR, Local recurrence.
Our analysis reveals that consistently excellent oncologic results can be expected for T1 glottic carcinomas that involve the mobile membranous vocal cord, although once the anterior commissure is involved, or if there is extension beyond the glottis or impaired cord mobility, vertical hemilaryngectomy should be used cautiously. On the basis of our review of the oncologic results in the literature, we do not recommend vertical hemilaryngectomy for those with advanced T2 lesions or any T3 or T4 glottic carcinomas.
Surgical Technique
A tracheostomy is routinely performed and a horizontal skin incision is used, which is separate from the tracheostomy site. The midline raphe between the strap muscles is dissected from the cricoid cartilage to just above the superior aspect of the thyroid cartilage. When feasible, we prefer to resect the window of thyroid cartilage adjacent to the vocal cord to allow reconstruction through imbrication laryngoplasty. The external thyroid perichondrium is scored in the midline with a blade, and the perichondrium is elevated as a single flap in continuity with the strap musculature. This is done with an elevator such as a Freer and by cutting the perichondrium sharply with a knife at its superior and inferior attachments to the thyroid cartilage. A variety of techniques have been described in which varying amounts of ipsilateral thyroid cartilage are excised, ranging from no cartilage to the entire ipsilateral ala. We use the technique described by Pleet and colleagues, in which a window of cartilage is outlined with a marker lateral to the level of the true vocal cord. The inferior aspect of the resected cartilage begins approximately 5 mm above the inferior aspect of the thyroid cartilage, and the resected portion is approximately 1.5 cm in height. It extends from the midline to the posterior aspect of the thyroid cartilage. At this point, the midline thyrotomy and other cuts are made with a knife, drill, or saw, depending on the degree of calcification of the thyroid cartilage and the preference of the surgeon. A No. 15 blade is used to make a midline vertical cricothyrotomy.
At this point the patient is paralyzed, the cords are held apart from below with a mosquito clamp, and a No. 12 blade is used to gently transect the anterior commissure, as in laryngofissure and cordectomy. The true and false cords are separated sharply up to the level of the petiole of the epiglottis. The cancer is visualized, and soft tissue resection is accomplished with a No. 15 blade for the anterior and posterior cuts. A right-angled Beaver blade or small right-angled scissors is useful for the posterior cut.
A variety of reconstructive options exist that include no replacement of the glottic level to allow healing to occur by secondary intention, strap muscle flap with thyroid cartilage preservation, and skin flaps. In imbrication laryngoplasty, we elevate a composite flap that includes the superior portion of the thyroid cartilage and the undermined false cord ( Fig. 108.9 ). This flap of vascularized, innervated false vocal cord is stabilized by the imbrication of the cartilage. It allows for soft tissue coverage from the false cord, but the inset of the superior thyroid cartilage on the inferior remnant also ensures medialization of the mucosal surface, which may improve phonation compared with no reconstruction.
Extended Procedures
A number of extensions of the standard procedure have been described.
Frontolateral Vertical Hemilaryngectomy
Frontolateral vertical hemilaryngectomy has been used for lesions that approach or involve the anterior commissure or opposite true vocal cord anteriorly. In this case, the vertical thyrotomy is made through the thyroid lamina of the less-involved side to allow for removal of the anterior angle of the thyroid cartilage, anterior commissure, and a portion of the contralateral true vocal cord. Even so, the 5-year Kaplan-Meier actuarial local control estimate for T1 tumors with anterior commissure involvement treated with a frontolateral vertical laryngectomy was 75% versus 96% without anterior commissure involvement.
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