Introduction

Cancer of the larynx arises from three subsites in the larynx: the supraglottis, glottis, and subglottis. Subglottic primaries comprise less than 5% of cancers of the larynx. The incidence of supraglottic versus glottic primaries varies, depending on the relative prevalence of alcohol and tobacco abuse and by geographic area. The optimal treatment of cancer of the larynx depends on primary tumor staging and the functional status of the larynx at the time of diagnosis. It is widely accepted that early stage (T1 and T2) cancers are treated equally well by either primary radiation or surgery. Advanced staged cancers, however, were originally thought to be best treated with total laryngectomy along with adjuvant chemoradiotherapy when indicated.

However, in the 1980s a paradigm shift evolved in the treatment of advanced cancer of the larynx. Many began advocating for “organ preservation therapy” (OPT) with definitive radiotherapy versus concurrent chemoradiotherapy in order to improve laryngectomy-free survival, following the results of the VA Laryngeal Cancer Group Study. Hoffman et al. analyzed the effects of this paradigm shift on outcomes and found that OPT has resulted in decreased overall survival for patients with cancer of the larynx in recent decades, particularly for those with T3 cancers. Consequently, it is now recognized that certain patients are better treated with primary surgery. The desire to preserve the functions of the larynx and improve survival has fueled a renewed interest in conservation surgery of the larynx.

Conservation partial laryngectomy is defined as the removal of a portion of the larynx with preservation of its respiratory, sphincteric, and vocal functions. Both endoscopic and open techniques have been developed for highly selected patients. Endoscopic techniques are discussed in Chapter 11 . Open techniques are separated into two categories: horizontal partial laryngectomy and vertical partial laryngectomy. Vertical partial laryngectomy is discussed in Chapter 13 . This chapter focuses on horizontal partial laryngectomy techniques.

For half a century, the only type of horizontal laryngectomy was supraglottic partial laryngectomy, which could only be performed on rare cancers confined only to the supraglottic larynx. In 1990, Laccourreye et al. described a new type of horizontal partial laryngectomy that removed both the true vocal cords and the entire thyroid cartilage. Since then, several modifications of horizontal partial laryngectomy have been described to remove glottic and supraglottic cancer. These modifications allow for resection of the superior, inferior, and lateral extensions of the cancer into the base of the tongue, piriform sinus, paraglottic space, and subglottis, as well as the use of remnant structures in the reconstruction. Surgeons must understand these techniques, as well as the indications and contraindications, in order to provide optimal treatment for patients with cancer of the larynx, who are likely to fail OPT and who are better treated by surgery.

Today, supracricoid partial laryngectomy (SCPL) with cricohyoidopexy (CHP) or cricohyoidoepiglottopexy (CHEP) is the most widely performed horizontal partial laryngectomy procedure because of to its reproducible oncologic and functional results in carefully selected patients. Supratracheal partial laryngectomy has been described; however, the results are less reproducible. This chapter will focus on supraglottic and supracricoid partial laryngectomy. If properly selected, most patients are decannulated, tolerate a regular diet, and enjoy improved overall and laryngectomy-free survival.

Key Operative Learning Points

• 1.
  

  Supraglottic laryngectomy has application limited to cancers of the supraglottic larynx and exophytic cancers of the base of the tongue confined to the vallecula ( Fig. 12.1 ).

  
  

  
  

  
  

  

  
  

  
  

  The pre-epiglottic space (shaded area) is bounded anteriorly by the thyrohyoid membrane. Superiorly, it is contained by the hyoepiglottic ligament. Cancer limited to the pre-epiglottic space is not a contraindication to supraglottic laryngectomy. However, extension of the cancer anterior to the pre-epiglottic space must be recognized and satisfactorily excised to ensure clear surgical margins.

  
  
  
  
• 2.
  

  The hyoid bone, at least one functional (innervated) cricoarytenoid unit, the cricoid cartilage, the recurrent laryngeal nerves, and the internal branches of the superior laryngeal nerves must be preserved for successful restoration of phonation and swallowing.

  
  
• 3.
  

  The ability to preserve the epiglottis determines the type of reconstruction: CHEP is performed for limited glottic cancers when the suprahyoid epiglottis can be preserved, and CHP is performed for glottic and supraglottic cancers where the epiglottis is involved and must be removed.

  
  
• 4.
  

  Extension to the base of the tongue, subglottis, or hypopharynx can make resection with negative margins impossible without an extended procedure, which downgrades function.

Preoperative Period

Physical Examination

• 1.
  

  Flexible laryngoscopy

  
  
  
  
  • a.
    

    This is the most important part of the examination. It allows for detailed evaluation of the primary cancer, including the subsites and key anatomic structures involved. It also allows for assessment of the effect of the cancer on laryngeal function and helps screen for synchronous second primary cancers.

    
    
  • b.
    

    Cancer extending to the anterior commissure should be evaluated. If present, the surgeon should suspect invasion of the thyroid cartilage, which makes the patient unlikely to be cured by primary radiation therapy (RT).

    
    
  • c.
    

    Careful assessment of the true vocal folds and cricoarytenoid joint mobility helps determine the patient’s candidacy for surgery. Atrophy of the true vocal fold suggests involvement of the ipsilateral cricoarytenoid joint and/or recurrent laryngeal nerve.

    
    
  • d.
    

    Subglottic extension is best assessed in the operating room through direct laryngoscopy using angled telescopes.

  
  
  
  
• 2.
  

  Videostroboscopy

  
  
  
  
  • a.
    

    This is indicated for cancer involving the true vocal cords and identifies the extent of mucosal involvement. Stroboscopy may help in planning the margins of resection and predict which patients will require removal of an arytenoid cartilage.

  
  
  
  
• 3.
  

  Behavior

  
  
  
  
  • a.
    

    Assessment of patient compliance with postoperative surveillance and rehabilitation is crucial. Patients who do not participate in intense swallowing therapy are unlikely to overcome the expected postoperative aspiration and may require placement of a percutaneous gastrostomy tube and/or prolonged tracheostomy.

  
  
  
  
• 4.
  

  Assessment of voice quality, respiration, and aspiration

  
  
• 5.
  

  Oral cavity and oropharynx

  
  
  
  
  • a.
    

    Screen for synchronous primaries and look for extension of the cancer that may be a contraindication to horizontal partial laryngectomy.

  
  
  
  
• 6.
  

  Laryngotracheal complex

  
  
  
  
  • a.
    

    Fixation to the anterior soft tissues suggests extra-laryngeal spread and requires a total laryngectomy.

    
    
  • b.
    

    Fixation to the spine makes the cancer unresectable.

  
  
  
  
• 7.
  

  Palpation of the thyroid gland

  
  
  
  
  • a.
    

    Extension to the thyroid gland requires a total laryngectomy with thyroid lobectomy or total thyroidectomy.

  
  
  
  
• 8.
  

  Presence of cervical lymphadenopathy

  
  
  
  
  • a.
    

    Clinically detectable lymphadenopathy may require a comprehensive neck dissection, depending on the extent of metastasis, whereas the clinically negative neck requires a selective neck dissection.

  
  

Imaging

• 1.
  

  CT

  
  
  
  
  • a.
    

    Larynx

    
    
    
    
    • 1)
      

      Thin-cut 1 mm axial CT scan through the larynx with coronal and sagittal reconstructions can detect extension of the cancer to pre-epiglottic and paraglottic spaces (see Figs. 12.1 and 12.2 ) as well as thyroid cartilage invasion with 75% accuracy. Adding analysis of gross radiographic signs of anterior commissure involvement (GRACI) signs improve accuracy in staging to 96%.

      
      

      
      

      
      

      

      
      

      
      

      The paraglottic space (shaded area) describes the submucosal soft tissue of the larynx contained by the thyroid cartilage externally. Cancer of the supraglottic larynx may spread submucosally through the paraglottic space. If the cancer extends inferior to the plane of the true vocal cord, as demonstrated in this illustration, supraglottic laryngectomy would be contraindicated because the surgeon would cut across the cancer at the level of the vocal cord.

      
      

    
    
    
    
  • b.
    

    Neck

    
    
    
    
    • 1)
      

      CT evaluation of cervical lymph node metastases is more sensitive than physical examination. Lymph nodes greater than 1 cm in the axial dimension that are round, hypodense, or demonstrate loss of the fatty hilum are considered suspicious for metastatic cancer.

    
    
    
    
  • c.
    

    Chest

    
    
    
    
    • 1)
      

      This is the most sensitive test to rule out synchronous cancers of the lung, the most common second primary in patients who have cancer of the larynx.

    
    

  
  
  
  
• 2.
  

  MRI

  
  
  
  
  • a.
    

    Neck

    
    
    
    
    • 1)
      

      MRI can evaluate the extent of involvement of the base of the tongue and identify which patients will require extended horizontal partial laryngectomy versus total laryngectomy.

    
    

  
  

Indications

• 1.
  

  Treatment of highly selected glottic cancer with the following characteristics:

  
  
  
  
  • a.
    

    T1-T3 glottic cancer that extends onto the supraglottis or entirely involves both vocal folds, but spares one arytenoid

    
    
  • b.
    

    T3 glottic cancers that have infiltrated the paraglottic space, causing vocal fold fixation without fixation of the cricoarytenoid joint

  
  
  
  
• 2.
  

  Treatment of highly selected supraglottic cancers with the following:

  
  
  
  
  • a.
    

    T2 supraglottic cancers that extend to the true vocal fold

    
    
  • b.
    

    T3 cancers that have infiltrated the paraglottic space, causing vocal fold fixation without fixation of the cricoarytenoid joint

  
  
  
  
• 3.
  

  Treatment of highly selected cancers with subglottic extension:

  
  
  
  
  • a.
    

    T2 or T3 cancers with less than 10 mm of anterior subglottic extension are unlikely to invade the cricoid cartilage and will still allow for negative margins. These patients remain candidates for SCPL with CHP or CHEP.

  
  
  
  
• 4.
  

  T3 glottic and supraglottic cancers with suspected invasion of the inner cortex of the thyroid cartilage.

  
  
• 5.
  

  Patients who failed primary RT and meet all of the previously noted criteria.