Horizontal Partial Laryngectomy

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 ).
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

History

1.
History of present illness
- a.
  Presenting symptom
  - 1)
    What was the initial presenting symptom: dysphonia, dysphagia, or odynophagia?
- b.
  Assess the current functional status of the larynx.
  - 1)
    Respiration
    - a)
      Does the patient have dyspnea at rest or orthopnea?
    - b)
      Does the patient have dyspnea on exertion?
  - 2)
    Phonation
    - a)
      Does the patient communicate well or is he or she difficult to understand?
  - 3)
    Deglutition
    - a)
      Does the patient experience aspiration with liquids or solids?
    - b)
      Has the patient had pneumonia in the past year?
    - c)
      Has the patient lost more than 10 pounds in the past year?
2.
Past medical history
- a.
  Prior treatment
  - 1)
    Has the patient had prior direct laryngoscopy with biopsy, CO ₂ laser excision, surgery, radiotherapy, or chemotherapy?
- b.
  Medical illness
  - 1)
    Does the patient have recurrent bronchitis, pneumonias?
  - 2)
    Does the patient have chronic obstructive pulmonary disease (COPD) or a cardiac history?
  - 3)
    Does the patient have cirrhosis with bleeding varices or other gastrointestinal bleeding?
  - 4)
    Consider using the Charleston Comorbidity Index or the Karnofsky Performance Status to identify those patients suited for surgery.
  - 5)
    What is the patient’s respiratory reserve; can the patient climb two flights of stairs?
- c.
  Surgery
  - 1)
    Is there a history of thyroidectomy or anterior cervical discectomy and fusion (possible superior laryngeal nerve injury)?
  - 2)
    Is there a history of prior neck surgery?
- d.
  Family history
  - 1)
    Do any first-degree relatives have cancer?
- e.
  Social history
  - 1)
    Tobacco use
    - a)
      Assessment of pack-year history and current use
    - b)
      Prior attempts to stop smoking and pharmacologic interventions
  - 2)
    Alcohol use
    - a)
      Daily volume versus drinks per week, alcohol abuse, and current use?
    - b)
      Prior attempts to stop drinking, symptoms of withdrawal/seizures?
  - 3)
    Occupation
  - 4)
    Does the patient rely on his or her voice at work?
- f.
  Medications
  - 1)
    Daily inhalers and/or oxygen for COPD?
  - 2)
    Does the patient take heart failure or antiplatelet medications?

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%.
- 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.

Contraindications

1.
Patients with general medical comorbidity, who are unable to undergo anesthesia or withstand postoperative aspiration
- a.
  Inability to climb two flights of stairs
- b.
  Karnofsky Performance Status less than 80
2.
Primary characteristics of the cancer making horizontal partial laryngectomy impossible:
- a.
  Interarytenoid/posterior commissure involvement
- b.
  Involvement of both arytenoid cartilages
- c.
  Cricoarytenoid joint involvement
- d.
  Cricoid cartilage involvement
- e.
  Subglottic extension greater than 10 mm
- f.
  Massive invasion of the inferior paraglottic space extending to the apex of the piriform sinus or piriform sinus involvement
- g.
  Greater than 2 cm of base of tongue involvement
- h.
  Extralaryngeal spread of the cancer

Note that advanced age was previously a relative contraindication to horizontal partial laryngectomy. However, recent literature indicates that age is of limited importance.

Preoperative Preparation

1.
Preoperative pulmonary function tests and arterial blood gases (ABG) can help in evaluating the severity of COPD; however, there is no defined parameter by which patients are selected for horizontal partial laryngectomy. Weber et al. report using the patient’s ability to climb two flights of stairs as helpful in selecting appropriate candidates.
2.
Perform operative direct laryngoscopy with biopsy using angled telescopes (30- and 70-degree), with palpation of the cricoarytenoid joint to assess mobility. Fixation is a contraindication to horizontal partial laryngectomy. Biopsy should also be performed in order to provide the histologic diagnosis of cancer. Operative examination and biopsy can be performed prior to the day of surgery or immediately prior to surgery with frozen section diagnosis (if one has a reliable pathologist). Biopsies done at outside institutions should be reviewed by in-house pathologists to confirm the diagnosis.

Consider preoperative evaluation of speech and swallowing as well as nutritional evaluation. This is not essential and can be done successfully in the immediate postoperative period by the appropriate team.

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