Introduction
The cricopharyngeus muscle is the major component of the upper esophageal sphincter (UES). The cricopharyngeus muscle is innervated by the pharyngeal plexus, which is composed of contributions from the vagus and glossopharyngeal nerves. Increasing evidence suggests that contributions from the recurrent laryngeal nerve (RLN) also innervate the cricopharyngeus muscle. The origin of the parasympathetic innervation is vagal, whereas sensory branches are derived from the glossopharyngeal nerve. Sympathetic fibers arise from the superior cervical ganglion and also join the pharyngeal plexus.
In its normal resting state, the cricopharyngeus muscle is in tonic contraction. When a swallow occurs, the cricopharyngeus relaxes during pharyngeal contraction (mediated by the vagus nerve), and anterior-superior movement of the larynx opens the UES to allow passage of the bolus into the esophagus; the bolus itself causes further distention of the UES. Dysphagia related to dysfunction of the UES results from (1) failure of cricopharyngeal relaxation, which can be due to lack of vagal innervation or loss of the normal viscoelastic properties of the muscle; (2) discoordination between cricopharyngeal relaxation and pharyngeal contraction; or (3) weakness of the suprahyoid musculature with poor elevation (anterosuperior movement) of the laryngeal complex.
Cricopharyngeal myotomy is used for alleviating cricopharyngeal dysfunction caused by lesions of the central and peripheral nervous systems, which affect laryngeal and pharyngeal muscle activity and coordination, as well as for the treatment of postsurgical dysphagia.
One of the most widely recognized manifestations of UES dysfunction is Zenker’s diverticulum. Although the first description of a pharyngoesophageal diverticulum is attributed to Ludlow in 1769, this entity became known as Zenker’s diverticulum after it was described in Zenker and Ziemssen’s Krankheiten des Oesophagus, a landmark compilation of esophageal pathology published in 1877. Killian clarified the anatomic site of origin as the space between the inferior constrictor muscle and the cricopharyngeus muscle—hence its name Killian’s triangle. Zenker’s diverticulum is a pulsion diverticulum that forms in the muscular dehiscence of Killian’s triangle as the UES fails to open with pharyngeal contraction, thus raising pressure in the pharynx ( Fig. 46.1 ). Other areas of weakness have been identified and can lead to variations of the site of origin of the diverticulum (Killian-Jamieson and Lamier triangles). Failure of UES opening may be the result of failure of cricopharyngeal relaxation or weakness of laryngeal elevation.
The standard treatment of a Zenker’s diverticulum includes a myotomy of the UES, which may be combined with resection of the diverticulum through a left-sided cervical incision; however, other techniques are also in common use. Dohlman and Mattson described an endoscopic technique for cricopharyngeal myotomy that has been modified with the introduction of bivalved endoscopes to provide better exposure of the party wall between the diverticulum and esophagus (containing the cricopharyngeus muscle) and the use of lasers, staplers, and harmonic scalpels for its transection. Advances in endoscopic instrumentation enabled Collard and associates to perform the first esophagodiverticulostomy with an endoscopic stapler in 1993. This procedure involves endoscopic division of the cricopharyngeus muscle with marsupialization of the diverticulum into the pharyngoesophagus. Modification of the stapler as described by Lang and colleagues allows the division to extend as close as possible to the inferior aspect of the diverticulum. Alternative endoscopic approaches use the CO 2 laser or the harmonic scalpel to divide the party wall between the esophagus and diverticulum.
Key Learning Points
- 1.
History of dysphagia and confirmation of upper esophageal dysfunction with imaging are essential in the diagnosis of dysfunction of the UES.
- 2.
Presence of normal or nearly normal pharyngeal function will optimize swallowing outcomes following cricopharyngeal myotomy.
- 3.
Transcervical and endoscopic approaches are valid treatments for Zenker’s diverticulum and multiple factors should be considered in selecting the best approach for each patient.
Preoperative Period
History
- 1.
History of present illness
- a.
Dysphagia to solids more than liquids
- b.
Dietary restrictions related to dysphagia
- c.
Regurgitation of undigested food
- d.
Unintentional weight loss
- e.
Recurrent pneumonia
- f.
Gastroesophageal reflux symptoms and response to treatment
- a.
- 2.
Past medical history and comorbid conditions
- a.
Cerebrovascular accident
- b.
Neurologic diseases (Parkinson’s, amyotrophic lateral sclerosis [ALS]) or neuromuscular diseases (inclusion body myositis)
- c.
History of head and neck surgery or radiation therapy to the neck
- a.
Physical Examination
- 1.
Palpation of laryngeal elevation with swallowing
- 2.
Flexible laryngoscopy
- a.
Rule out other pathologies such as tumor or infection.
- b.
Pooling of secretions in hypopharynx
- a.
- 3.
Functional endoscopic examination of swallowing (FEES)
- a.
Hypopharyngeal residue is suggestive of UES dysfunction.
- b.
Evaluate for aspiration.
- c.
Regurgitation (most commonly to the left piriform)
- a.
Imaging
- 1.
Barium esophagram
- a.
Prominence of the cricopharyngeus muscle on lateral view at the level of C5-C7 vertebral bodies
- b.
Failure of relaxation of the cricopharyngeus muscle ( Fig. 46.2 )
Fig. 46.2
Barium esophagogram (lateral view) demonstrating failure of relaxation of the cricopharyngeus muscle (arrow).
- c.
Presence of Zenker’s diverticulum ( Fig. 46.3 )
Fig. 46.3
Barium esophagogram demonstrating Zenker’s diverticulum (arrow).
- a.
- 2.
Modified barium swallow
- a.
Identify and quantify laryngeal penetration and aspiration.
- b.
Evaluate the coordination of swallow and laryngeal elevation.
- a.
- 3.
High-resolution impedance manometry
- a.
Allows for measurement of pharyngeal strength, UES relaxation, and intrabolus pressures
- b.
During swallowing, normal pharyngeal contraction with elevated UES residual pressure is suggestive of UES dysfunction.
- a.
Indications
- •
Moderate to severe dysphagia symptoms with poor UES opening on Modified barium swallow MBS
- •
Normal or nearly normal pharyngeal function, which is required for propulsion of the bolus
- •
Adequate laryngeal elevation, which is required for opening of the UES
- •
- •
Dysphagia causing significant weight loss
- •
Complications of aspiration (i.e., recurrent pneumonia)
Contraindications
- •
Medically unfit
- •
Diffuse pharyngeal motor abnormalities and poor anterosuperior laryngeal elevation
- •
Comorbid conditions such as ALS, Parkinson’s disease, or cerebellar atrophy that would contribute to diffuse pharyngeal motor abnormalities
- •
Conditions that affect the opening of the lower esophageal sphincter LES (achalasia, stricture)
- •
Severe esophageal dismotility with antegrade regurgitation
- •
Uncontrolled gastroesophageal reflux disease GERD
Preoperative Preparation
- •
Discontinue antiplatelet drugs and herbal medicines.
- •
Optimize GERD control.
Operative Period
Anesthesia
- •
General anesthesia is preferred.
- •
Local anesthesia can be used if the patient’s condition does not permit general anesthesia (transcervical approach only).
Positioning
- •
Supine
- •
Shoulder roll facilitates exposure for transcervical approach
Perioperative Antibiotic Prophylaxis
- •
Antibiotics are administered during induction of anesthesia.
- •
Choices
Clindamycin
Ampicillin-sulbactam
Cephalosporin and metronidazole
Monitoring
Routine anesthesia monitoring
Instruments and Equipment to Have Available
- •
Endoscopic approach for Zenker’s diverticulum
- •
Weerda diverticuloscope
- •
Endo-GIA stapler
- •
Endoscopic stitch or alligator forceps for retraction
- •
Zero-degree and 30-degree endoscopes
- •
- •
Transcervical approach
- •
Rigid esophagoscope
- •
Standard head and neck set
- •
Bipolar cautery
- •
Key Anatomic Landmarks
- •
Cricoid cartilage marks the level of the cricopharyngeus muscle
- •
Cricothyroid joint is the entry point of the RLN
- •
Cricopharyngeus muscle can be distinguished from inferior pharyngeal constrictor by the horizontal orientation of its fibers
Prerequisite Skills
- •
Rigid esophagoscopy
- •
Transcervical approach to the retropharyngeal space
- •
Closure of pharyngotomy
Operative Risks
- •
Injury to the teeth
- •
Contained salivary leak or salivary fistula
- •
Bleeding
- •
Mediastinitis
Surgical Technique
Cricopharyngeal Myotomy
- •
A nasogastric tube (NG) is placed.
- •
Transverse incision in a skinfold at the level of the cricoid cartilage
- •
Subplatysmal flaps are elevated inferiorly to the clavicle and superiorly above the thyroid notch.
- •
Sharp separation of the sternocleidomastoid (SCM) muscle from the strap muscles exposes the carotid sheath.
- •
The SCM and carotid sheath are separated from the strap muscles, thyroid gland, and laryngotracheal complex and retracted anterolaterally and rotated to the right to allow entry into the retropharyngeal-prevertebral space ( Fig. 46.4 ).
