Dysphagia: Diagnosis and Treatment of Esophageal Motility Disorders

Dysphagia: Diagnosis and Treatment of Esophageal Motility Disorders provides a interdisciplinary overview of the diagnosis and management of dysphagia and other esophageal symptoms. All aspects of dysphagia are covered, with detailed consideration of both physiology and evaluation methods. Hot topics include coverage on the pharmacological causes of dysphagia, the physiology of normal swallowing, ambulatory pH monitoring as well as recurrent dysphagia after treatments. The content is grounded in evidence-based medicine that is the result of clinical outcome research, both prospective and randomized, making this the perfect reference for clinical researchers and a go-to for general surgeons, foreguts surgeons, thoracic surgeons and gastroenterologists.

• Presents a unified interdisciplinary approach to dysphagia covering perspectives from multiple specialties
• Provides in-depth analysis of radiologic, endoscopic and manometric evaluation of dysphagia including analysis of the Chicago Classification 4.0, which has changed previous paradigms
• Includes comprehensive coverage of dysphagia from evidence-based medicine that is the result of clinical outcome research, both prospective and randomized

• Language: English
• Publisher: Academic Press
• Release date: Jan 6, 2023
• ISBN: 9780323912990

Book preview

Preface

Benign esophageal diseases are a heterogenous group of disorders that may cause diverse symptoms, such as heartburn, regurgitation, and dysphagia. A motility disorder is often present, either primary such as in achalasia or secondary such as in gastroesophageal reflux disease.

The treatment of these disorders is based on a thorough work-up that includes a barium swallow, upper endoscopy, esophageal manometry, and pH monitoring. The goal is to characterize each disorder precisely, with the aim of tailoring treatment. The best results are obtained in centers where a multidisciplinary team composed of radiologists, gastroenterologists, and surgeons is present and able to offer different treatment options.

The authors of the 13 chapters have been carefully selected as they are experts in the treatment of these disorders, with many years of experience. Their recommendations for diagnosis and treatment are both based on evidence and personal experience. We do hope that our effort will be useful for both physicians in training as well as practicing gastroenterologists and surgeons.

Marco G. Patti

Francisco Schlottmann

Fernando Augusto Mardiros Herbella

Chapter 1

Normal swallowing physiology

Fernando Augusto Mardiros Herbellaa, Rafael Melillo Laurino Netob, Renata Azevedoc and Marco G. Pattid

aDepartment of Surgery, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil

bDepartment of Surgery, Nove de Julho University, Mandaqui Hospital, São Paulo, Brazil

cDepartment of Speech Therapy, Federal University of São Paulo, São Paulo, Brazil

dDepartment of Surgery, University of Virginia, Charlottesville, VA, United States

Introduction

Swallowing is defined as a process in which liquid or solid substances arrive from mouth to stomach, passing through the pharynx and esophagus. This process occurs approximately 600 times a day, especially while awake and during feeding, but in a much smaller number, approximately 50 times a day, it also happens during sleep.¹

It is a very complex behavior learned early in the individual's development. Evidence shows that already in intrauterine life, around the 15th week of pregnancy, this process already occurs, seeking to regulate the volume of amniotic fluid. The process of sucking, swallowing, and breathing already takes place in newborns and develops with the introduction of new foods, allowing for their conscious control in early childhood.²

Despite being an innate function of the body, it is a complex process involving the coordinated function of several muscles and nerves.

Functional anatomy

Many anatomical structures participate in the swallowing process. Several bones (mandible, maxilla, hard palate, hyoid, and cervical vertebrae), cartilage (thyroid, cricoid, arytenoid, and epiglottis), teeth, salivary glands (parathyroid, sublingual, and submandibular), and muscles take part in this process (Fig. 1.1).

Figure 1.1 Midsagittal view of head and neck. Public Domain (from https://commons.wikimedia.org/wiki/File:Sobo_1906_328.png).

After passing through the oral cavity, which includes lips, oral mucosa, teeth, gums, anterior two-thirds of the tongue, floor of the mouth and hard palate, food enters the pharynx, which is an organ common to the digestive and respiratory tract, allowing communication between these two systems. The pharynx is located in the posterior region of the nose, mouth, and larynx, being thus divided into three parts: nasopharynx, oropharynx, and laryngopharynx. After leaving pharynx, food enters the esophagus, where it is transported to the stomach (Fig. 1.2).

Figure 1.2 Posterior view of head and neck. Public Domain (from https://commons.wikimedia.org/wiki/File:Sobo_1906_365.png).

In particular, regarding the participation of muscles in this process, we must keep in mind that more than 30 pairs of these are activated during swallowing. In Table 1.1, we have individually described each one, and how they are didactically grouped.³,⁴ All muscles, involved in swallowing are striated, with the exception of the medial and distal esophagus, which have segments that are partially or completely smooth muscle. Muscle movements are controlled by several cranial and peripheral nerves and are coordinated within the brain stem. Somatic afferent and efferent feedback are provided primarily via cranial and peripheral nerves (for striated musculature) and an autonomic enteric system (for smooth muscle).

Table 1.1

Swallowing phases

Swallowing process is divided into four distinct phases: oral preparatory phase, oral propulsive phase, pharyngeal phase, and esophageal phase. Although the two oral phases have voluntary control, the other two are characterized by being reflex actions. It should also be noted that both oral and pharyngeal phases of swallowing share anatomical structures with the respiratory tract, what it does the protection of the airway, being of great importance throughout the process.⁵

1) Oral preparatory phase

In the first phase of swallowing, there is a fractionation of food with formation of a cohesive bolus through mastication.⁶,⁷

Facial muscles (orbicularis oris and buccinators) closing the lips, as well as soft palate approaching to base of the tongue, delimit the oral cavity and prevent the premature escape of food to oropharynx, protecting the airway. Mastication muscles (masseter, temporalis, and medial and lateral pterygoid muscles) are used when solid food is ingested, promoting active movement of the jaw. On the other hand, tongue movements place food particles between the teeth, which are also mixed with saliva. Once mastication is complete, the bolus is contained between the dorsal surface of the tongue and the hard palate.⁸,⁹

2) Oral propulsive phase

This phase begins after a cohesive bolus formation, with its transport backwards to the oropharynx, through oral cavity. Facial muscles remain contracted and soft palate rises, promoting isolation of the nasal cavity from oropharynx, and creating a closed pressure loop that facilitates bolus transport.

Through the action of intrinsic and extrinsic muscles of the tongue (genioglossus, hyoglossus, styloglossus, palatoglossus, superior longitudinal), a wave-shaped movement of alimentary bolus, which passes from oral cavity to oropharynx, takes place. The entrance of the bolus into oropharynx is also facilitated by the contraction of muscles at base of the tongue (via contraction of hyoglossus muscle) and elevation of soft palate by contraction of this region muscles (levator veli palatini and musculus uvulae) (Fig. 1.3A).

Figure 1.3 Fluoroscopy of swallowing phases (A—oral, B—pharyngeal, C—esophageal).

Stabilization of jaw and tongue at this stage is achieved by activating masticatory (temporalis, masseter, and medial and lateral pterygoids) and suprahyoid muscles (mylohyoid, geniohyoid, anterior digastric, posterior digastric, and stylohyoid).¹⁰,¹¹

3) Pharyngeal phase

Although this phase of swallowing lasts approximately just 1 second, it is considered the most complex of all, requiring coordinated action of practically all muscles involved in this whole process¹² (Table 1.1).

The involuntary trigger for beginning this phase is the passage of alimentary bolus through anterior faucial pillar area, being influenced by the way in which transport took place in oral phase, as well as by characteristics (texture, taste, volume) of swallowed food.¹³,¹⁴

After this trigger, pharynx rises, by contraction of pharyngeal muscles (lateral cricoarytenoid, transverse arytenoid, and thyroarytenoid) and tongue base retraction through contraction of its extrinsic muscles (hyoglossus and styloglossus) and pharyngeal constrictors. This coordinated action, which occurs at a rate of 9 to 25 cm/s, is known as pharyngeal peristalsis, and results in pushing the bolus through the pharynx and into the proximal esophagus.¹⁵

Simultaneously with elevation of pharynx, there is also an elevation of hyoid bone by contraction of suprahyoid muscles (mylohyoid, stylohyoid, geniohyoid, and anterior and posterior bellies of digastric). This anterior and superior movement of larynx and hyoid bone, in addition to protecting airway, by aligning larynx below base of the tongue and inverting epiglottis, creates a source of negative pressure below bolus, that generates a suction mechanism, as well as creates a biomechanical force, that forces opening of upper esophageal sphincter (UES) (Fig. 1.3B).

Assuming that labial and nasopharyngeal seals have remained intact, opening of UES creates an additional source of negative pressure, or suction force in upper esophagus, that greatly enhances the efficiency of pharyngeal bolus transit.¹³

As in the two previous swallow phases, in order to keep tongue and jaw stabilized, mastication muscles must remain active throughout the entire pharyngeal phase.

4) Esophageal phase

Esophageal phase of swallowing begins when bolus passes through UES (Fig. 1.3C).

UES opening happens due to the sum of biomechanical forces and relaxation of cricopharyngeal muscle. This short-term relaxation (0.5–1.2 seconds) takes place just long enough for food to pass into esophagus through UES, after which cricopharynx returns to its contracted state, preventing retrograde flow of bolus into hypopharynx.¹⁶,¹⁷

Esophageal peristalsis begins after food passes through UES, promoting the transport of the bolus to stomach through lower esophageal sphincter. This esophageal peristaltic wave travels inferiorly at a rate of approximately 3–4 cm/s and serves to squeeze the bolus through esophagus. Esophageal transit lasts between 8 and 13 seconds. Several secondary peristaltic waves also occur up to an hour after swallow and help to clear any remaining esophageal