Esophagus and Diaphragmatic Hernia PDF

25 Esophagus and Diaphragmatic Hernia chapter Blair A. Jobe, John G. Hunter, and David I. Watson Surgical Anatomy 1009 Diaphragmatic R...

25 Esophagus and Diaphragmatic Hernia chapter Blair A. Jobe, John G. Hunter, and David I. Watson Surgical Anatomy 1009 Diaphragmatic Repair / 1048 Carcinoma of the Esophagus 1068 Physiology1015 The Short Esophagus and PEH / 1049 Clinical Manifestations / 1068 Swallowing Mechanism / 1015 Results / 1049 General Approach to Physiologic Reflux / 1017 Schatzki’s Ring 1049 Esophageal Cancer / 1069 Staging of Esophageal Cancer / 1069 Assessment of Esophageal Scleroderma1050 Clinical Approach to Carcinoma of the Function1018 Eosinophilic Esophagitis 1051 Esophagus and Cardia / 1070 Tests to Detect Structural Symptoms / 1051 Palliation of Esophageal Cancer / 1074 Abnormalities / 1018 Signs / 1051 Surgical Treatment / 1074 Tests to Detect Functional Pathology / 1051 Abnormalities / 1019 Comparative Studies of Esophagectomy Treatment / 1051 Technique / 1077 Video- and Cineradiography / 1028 Tests to Detect Increased Motility Disorders of the Alternative Therapies / 1077 Exposure to Gastric Juice / 1028 Pharynx and Esophagus 1052 Sarcoma of the Esophagus 1078 Tests of Duodenogastric Function / 1030 Clinical Manifestations / 1052 Benign Tumors and Cysts 1080 Motility Disorders of the Pharynx and Gastroesophageal Reflux Leiomyoma / 1081 Upper Esophagus—Transit Disease1031 Dysphagia / 1052 Esophageal Cyst / 1083 The Human Antireflux Mechanism Diagnostic Assessment of the Esophageal Perforation 1083 and the Pathophysiology of Cricopharyngeal Segment / 1052 Diagnosis / 1083 Gastroesophageal Reflux Disease / 1032 Motility Disorders of the Esophageal Management / 1084 Complications Associated With Body and Lower Esophageal Gastroesophageal Reflux Disease / 1033 Mallory-Weiss Syndrome 1085 Sphincter / 1055 Metaplastic (Barrett’s Esophagus) Caustic Injury 1086 and Neoplastic (Adenocarcinoma) Operations for Esophageal Motor Pathology / 1086 Complications / 1035 Disorders and Diverticula 1060 Clinical Manifestations / 1086 Respiratory Complications / 1035 Long Esophageal Myotomy for Motor Treatment / 1086 Disorders of the Esophageal Body / 1060 Surgical Therapy for Gastroesophageal Acquired Fistula 1088 Reflux Disease / 1038 Myotomy of the Lower Esophageal Sphincter (Heller Myotomy) / 1063 Techniques of Esophageal Primary Antireflux Repairs / 1040 Open Esophageal Myotomy / 1065 Reconstruction1089 Giant Diaphragmatic Laparoscopic Cardiomyotomy / 1065 Partial Esophageal Resection / 1089 (Hiatal) Hernias 1045 Per Oral Endoscopic Reconstruction After Total Incidence and Etiology / 1045 Myotomy (POEM) / 1065 Esophagectomy / 1089 Clinical Manifestations / 1047 Outcome Assessment of the Therapy for Composite Reconstruction / 1090 Diagnosis / 1047 Achalasia / 1065 Vagal Sparing Esophagectomy Pathophysiology / 1048 Esophageal Resection for End-Stage Motor With Colon Interposition / 1090 Treatment / 1048 Disorders of the Esophagus / 1068 SURGICAL ANATOMY cartilage and at its lower end to the diaphragm; during swal- lowing, the proximal points of fixation move craniad the dis- The esophagus is a muscular tube that starts as the continu- tance of one cervical vertebral body. ation of the pharynx and ends as the cardia of the stomach. The esophagus lies in the midline, with a deviation to the When the head is in a normal anatomic position, the transi- left in the lower portion of the neck and upper portion of the tion from pharynx to esophagus occurs at the lower border of thorax, and returns to the midline in the midportion of the tho- the sixth cervical vertebra. Topographically this corresponds rax near the bifurcation of the trachea (Fig. 25-2). In the lower to the cricoid cartilage anteriorly and the palpable transverse portion of the thorax, the esophagus again deviates to the left process of the sixth cervical vertebra laterally (Fig. 25-1). The and anteriorly to pass through the diaphragmatic hiatus. esophagus is firmly attached at its upper end to the cricoid  Key Points 1 Benign esophageal disease is common and is best evaluated increases the future risk of cancer by >40x compared to indi- with thorough physiologic testing (high resolution esopha- viduals without Barrett’s esophagus. geal motility, 24-hour ambulatory pH measurement, and/or 4 Giant hiatal hernia, otherwise known as paraesophageal her- esophageal impedance testing) and anatomic testing (esoph- nia, should be repaired when symptomatic or associated with agoscopy, video esophagography, and/or computed tomog- iron deficiency anemia. Laparoscopic hiatal hernia repair raphy [CT] scanning). with fundoplication is the most common approach to repair. 2 Gastroesophageal reflux disease (GERD) is the most com- 5 Achalasia is the most common primary esophageal motor disorder. It is characterized by an absence of peristalsis and mon disease of the gastrointestinal tract for which patients a hypertensive nonrelaxing lower esophageal sphincter. It is seek medical therapy. When GERD symptoms (heartburn, best treated with laparoscopic Heller myotomy and partial regurgitation, chest pain, and/or supraesophageal symptoms) fundoplication. are troublesome despite adequately dosed PPI, surgical cor- rection may be indicated. 6 Most esophageal cancer presents with dysphagia, at which time it has invaded the muscularis of the esophagus and is 3 Barrett’s esophagus is the transformation of the distal esoph- often associated with lymph node metastases. The preferred ageal epithelium from squamous to a specialized columnar treatment at this stage is multimodality therapy with chemo- epithelium capable of further neoplastic progression. The radiation therapy followed by open or minimally invasive detection of Barrett’s esophagus on endoscopy and biopsy esophagectomy. Three normal areas of esophageal narrowing are evident depending on the distention of the esophagus by the passage on the barium esophagogram or during esophagoscopy. The of food, but has been measured at 1.6 to 1.9 cm. These normal uppermost narrowing is located at the entrance into the esopha- constrictions tend to hold up swallowed foreign objects, and the gus and is caused by the cricopharyngeal muscle. Its luminal overlying mucosa is subject to injury by swallowed corrosive diameter is 1.5 cm, and it is the narrowest point of the esopha- liquids due to their slow passage through these areas. gus. The middle narrowing is due to an indentation of the ante- Figure 25-3 shows the average distance in centimeters rior and left lateral esophageal wall caused by the crossing of the measured during endoscopic examination between the incisor left main stem bronchus and aortic arch. The luminal diameter at teeth and the cricopharyngeus, aortic arch, and cardia of the this point is 1.6 cm. The lowermost narrowing is at the hiatus of stomach. Manometrically, the length of the esophagus between the diaphragm and is caused by the gastroesophageal sphincter the lower border of the cricopharyngeus and upper border of the mechanism. The luminal diameter at this point varies somewhat, lower sphincter varies according to the height of the individual. Figure 25-1. A. Topographic rela­ a tionships of the cervical esophagus: b (a) hyoid bone, (b) thyroid c cartilage, (c) cricoid cartilage, (d) d thyroid gland, (e) sternoclavicular. B. Lateral radio-graphic appea­ rance with landmarks identified as e labeled in A. The location of C6 is also included (f). (Reproduced with permission from Shields TW: A General Thoracic Surgery, 3rd ed. Philadelphia, PA: Lea & Febiger; 1010 B 1989.)  1011 CHAPTER 25 ESOPHAGUS AND DIAPHRAGMATIC HERNIA A B Figure 25-2. Barium esophagogram. A. Posterior-anterior view. White arrow shows deviation to left. Black arrow shows return to midline. B. Lateral view. Black arrow shows anterior deviation. (Reproduced with permission from Shields TW: General Thoracic Surgery, 3rd ed. Philadelphia, PA: Lea & Febiger; 1989.) Incisor teeth The pharyngeal musculature consists of three broad, flat, overlapping fan-shaped constrictors (Fig. 25-4). The opening of the esophagus is collared by the cricopharyngeal muscle, Pharynx which arises from both sides of the cricoid cartilage of the lar- 15cm 14cm ynx and forms a continuous transverse muscle band without an interruption by a median raphe. The fibers of this muscle 24–26cm Upper sphincter (C6) Superior pharyngeal Aortic arch constrictor m. (T4) Middle pharyngeal constrictor m. 25cm 23cm 40cm Inferior pharyngeal 38cm constrictor m. Cricopharyngeus m. Lower sphincter Esophagus (T11) A B Figure 25-3. Important clinical endoscopic measurements of the Figure 25-4. External muscles of the pharynx. A. Posterolateral esophagus in adults. (Reproduced with permission from Shields view. B. Posterior view. Dotted line represents usual site of myotomy. TW: General Thoracic Surgery, 3rd ed. Philadelphia, PA: Lea & (Reproduced with permission from Shields TW: General Thoracic Febiger; 1989.) Surgery, 3rd ed. Philadelphia, PA: Lea & Febiger; 1989.) 1012 blend inseparably with those of the inferior pharyngeal constric- both the vagal nerves and the esophageal nerve plexus lie on tor above and the inner circular muscle fibers of the esophagus the muscular wall of the esophagus. below. Some investigators believe that the cricopharyngeus is Dorsally, the thoracic esophagus follows the curvature of part of the inferior constrictor; that is, that the inferior constric- the spine and remains in close contact with the vertebral bod- tor has two parts, an upper or retrothyroid portion having diago- ies. From the eighth thoracic vertebra downward, the esopha- nal fibers, and a lower or retrocricoid portion having transverse gus moves vertically away from the spine to pass through the fibers. Keith in 1910 showed that these two parts of the same hiatus of the diaphragm. The thoracic duct passes through the muscle serve totally different functions. The retrocricoid portion hiatus of the diaphragm on the anterior surface of the verte- serves as the upper sphincter of the esophagus and relaxes when bral column behind the aorta and under the right crus. In the the retrothyroid portion contracts, to force the swallowed bolus thorax, the thoracic duct lies dorsal to the esophagus between from the pharynx into the esophagus. the azygos vein on the right and the descending thoracic aorta The cervical portion of the esophagus is approximately on the left. PART II 5 cm long and descends between the trachea and the vertebral The abdominal portion of the esophagus is approximately column, from the level of the sixth cervical vertebra to the level 2 cm long and includes a portion of the lower esophageal of the interspace between the first and second thoracic verte- sphincter (LES). It starts as the esophagus passes through the brae posteriorly, or the level of the suprasternal notch anteriorly. diaphragmatic hiatus and is surrounded by the phrenoesopha- The recurrent laryngeal nerves lie in the right and left grooves geal membrane, a fibroelastic ligament arising from the subdia- SPECIFIC CONSIDERATIONS between the trachea and the esophagus. The left recurrent nerve phragmatic fascia as a continuation of the transversalis fascia lies somewhat closer to the esophagus than the right, owing to lining the abdomen (Fig. 25-7). The upper leaf of the membrane the slight deviation of the esophagus to the left, and the more attaches itself in a circumferential fashion around the esopha- lateral course of the right recurrent nerve around the right sub- gus, about 1 to 2 cm above the level of the hiatus. These fibers clavian artery. Laterally, on the left and right sides of the cervi- blend in with the elastic-containing adventitia of the abdominal cal esophagus are the carotid sheaths and the lobes of the thyroid esophagus and the cardia of the stomach. This portion of the gland. esophagus is subjected to the positive-pressure environment of The thoracic portion of the esophagus is approximately the abdomen. 20 cm long. It starts at the thoracic inlet. In the upper portion The musculature of the esophagus can be divided into an of the thorax, it is in intimate relationship with the posterior outer longitudinal and an inner circular layer. The upper 2 to wall of the trachea and the prevertebral fascia. Just above the 6 cm of the esophagus contains only striated muscle fibers. tracheal bifurcation, the esophagus passes to the right of the From then on, smooth muscle fibers gradually become more aorta. This anatomic positioning can cause a notch indentation abundant. Most clinically significant esophageal motility dis- in its left lateral wall on a barium swallow radiogram. orders involve only the smooth muscle in the lower two-thirds Immediately below this notch, the esophagus crosses both the of the esophagus. When a long surgical esophageal myotomy is bifurcation of the trachea and the left main stem bronchus, indicated, the incision needs to extend only this distance. owing to the slight deviation of the terminal portion of the The longitudinal muscle fibers originate from a crico- trachea to the right by the aorta (Fig. 25-5). From there esophageal tendon arising from the dorsal upper edge of the down, the esophagus passes over the posterior surface of anteriorly located cricoid cartilage. The two bundles of mus- the subcarinal lymph nodes (LNs), and then descends over the cle diverge and meet in the midline on the posterior wall of pericardium of the left atrium to reach the diaphragmatic hiatus the esophagus about 3 cm below the cricoid (see Fig. 25-4). (Fig. 25-6). From the bifurcation of the trachea downward, From this point on, the entire circumference of the esophagus is Ascending aorta Thymus Left main stem bronchus Pericardium Bottom of aortic arch Superior vena cava a e c Tracheal carina d b Descending Right main stem aorta bronchus Esophagus IV B A Figure 25-5. A. Cross-section of the thorax at the level of the tracheal bifurcation. B. Computed tomographic scan at same level viewed from above: (a) ascending aorta, (b) descending aorta, (c) tracheal carina, (d) esophagus, (e) pulmonary artery. (Reproduced with permission from Shields TW: General Thoracic Surgery, 3rd ed. Philadelphia, PA: Lea & Febiger; 1989.)  Pericardium 1013 Right ventricle Left ventricle f Right atrium Left atrium e d Pericardium Esophagus c g b Pleura a Aorta CHAPTER 25 ESOPHAGUS AND DIAPHRAGMATIC HERNIA Pleura VII B A Figure 25-6. A. Cross-section of the thorax at the midleft atrial level. B. Computed tomographic scan at same level viewed from above: (a) aorta, (b) esophagus, (c) left atrium, (d) right atrium, (e) left ventricle, (f) right ventricle, (g) pulmonary vein. (Reproduced with permission from Shields TW: General Thoracic Surgery, 3rd ed. Philadelphia, PA: Lea & Febiger; 1989.) covered by a layer of longitudinal muscle fibers. This configura- form a longitudinal plexus, giving rise to an intramural vascular tion of the longitudinal muscle fibers around the most proximal network in the muscular and submucosal layers. As a conse- part of the esophagus leaves a V-shaped area in the posterior quence, the esophagus can be mobilized from the stomach to wall covered only with circular muscle fibers. Contraction of the level of the aortic arch without fear of devascularization and the longitudinal muscle fibers shortens the esophagus. The cir- ischemic necrosis. Caution, however, should be exercised as to cular muscle layer of the esophagus is thicker than the outer the extent of esophageal mobilization in patients who have had longitudinal layer. In situ, the geometry of the circular muscle a previous thyroidectomy with ligation of the inferior thyroid is helical and makes the peristalsis of the esophagus assume a arteries proximal to the origin of the esophageal branches. wormlike drive, as opposed to segmental and sequential squeez- Blood from the capillaries of the esophagus flows into ing. As a consequence, severe motor abnormalities of the esoph- a submucosal venous plexus, and then into a periesophageal agus assume a corkscrew-like pattern on the barium swallow radiogram. The cervical portion of the esophagus receives its main blood supply from the inferior thyroid artery. The thoracic por- tion receives its blood supply from the bronchial arteries, with Esophageal branch 75% of individuals having one right-sided and two left-sided Inferior thyroid branches. Two esophageal branches arise directly from the artery aorta. The abdominal portion of the esophagus receives its blood supply from the ascending branch of the left gastric artery and from inferior phrenic arteries (Fig. 25-8). On entering the wall of the esophagus, the arteries assume a T-shaped division to Superior left Right bronchial bronchial artery artery Inferior left bronchial artery Aortic esophageal Phreno-esophageal membrane arteries Diaphragm (Ascending leaf) Parietal peritoneum Phreno-esophageal membrane (Descending leaf) Visceral peritoneum Para-esophageal fat pad Ascending branches of left gastric artery Left gastric artery Figure 25-7. Attachments and structure of the phrenoesophageal membrane. Transversalis fascia lies just above the parietal peri- Figure 25-8. Arterial blood supply of the esophagus. (Reproduced toneum. (Reproduced with permission from Shields TW: General with permission from Shields TW: General Thoracic Surgery, 3rd ed. Thoracic Surgery, 3rd ed. Philadelphia, PA: Lea & Febiger; 1989.) Philadelphia, PA: Lea & Febiger; 1989.) 1014 venous plexus from which the esophageal veins originate. In the Recurrent cervical region, the esophageal veins empty into the inferior thy- laryngeal roid vein; in the thoracic region, they empty into the bronchial, nerves Right vagus nerve azygos, or hemiazygos veins; and in the abdominal region, they empty into the coronary vein (Fig. 25-9). The submucosal Left vagus nerve venous networks of the esophagus and stomach are in continuity Right recurrent with each other, and, in patients with portal venous obstruction, laryngeal nerve this communication functions as a collateral pathway for portal Left recurrent blood to enter the superior vena cava via the azygos vein. laryngeal nerve The parasympathetic innervation of the pharynx and esophagus is provided mainly by the vagus nerves. The con- strictor muscles of the pharynx receive branches from the PART II pharyngeal plexus, which is on the posterior lateral surface of the middle constrictor muscle, and is formed by pharyngeal Anterior esophageal Thoracic chain branches of the vagus nerves with a small contribution from cra- plexus nial nerves IX and XI (Fig. 25-10). The cricopharyngeal sphinc- ter and the cervical portion of the esophagus receive branches SPECIFIC CONSIDERATIONS Left or anterior from both recurrent laryngeal nerves, which originate from the vagal trunk vagus nerves—the right recurrent nerve at the lower margin of the subclavian artery and the left at the lower margin of the aortic arch. They are slung dorsally around these vessels and ascend in the groove between the esophagus and trachea, giving Right or posterior branches to each. Damage to these nerves interferes not only vagal trunk with the function of the vocal cords but also with the function of the cricopharyngeal sphincter and the motility of the cervical esophagus, predisposing the individual to pulmonary aspiration Figure 25-10. Innervation of the esophagus. (Reproduced with permission from Shields TW: General Thoracic Surgery, 3rd ed. on swallowing. Philadelphia, PA: Lea & Febiger; 1989.) Afferent visceral sensory pain fibers from the esophagus end without synapse in the first four segments of the thoracic spinal cord, using a combination of sympathetic and vagal path- ways. These pathways are also occupied by afferent visceral plexus (Fig. 25-11). There are more lymph vessels than blood sensory fibers from the heart; hence, both organs have similar capillaries in the submucosa. Lymph flow in the submucosal symptomatology. plexus runs in a longitudinal direction, and, on injection of a The lymphatics located in the submucosa of the esopha- contrast medium, the longitudinal spread is seen to be about six gus are so dense and interconnected that they constitute a single times that of the transverse spread. In the upper two-thirds of the esophagus, the lymphatic flow is mostly cephalad, and, in the lower third, caudad. In the thoracic portion of the esophagus, Inferior thyroid veins Superior Internal jugular paraesophageal nodes nodes Paratracheal nodes Accessory azygous vein Pulmonary hilar Hemiazygous vein nodes Subcarinal nodes Azygous vein Inferior paraesophageal nodes Parahiatal nodes Splenic artery Short nodes gastric Left gastric artery nodes Coronary vein veins Hepatic artery nodes Portal vein Superior mesenteric Celiac artery nodes vein Splenic vein Figure 25-11. Lymphatic drainage of the esophagus. (Reproduced Figure 25-9. Venous drainage of the esophagus. (Reproduced with with permission from DeMeester TR, Barlow AP. Surgery and cur- permission from Shields TW: General Thoracic Surgery, 3rd ed. rent management for cancer of the esophagus and cardia: Part I, Philadelphia, PA: Lea & Febiger; 1989.) Curr Probl Surg. 1988 Jul;25(7):475-531.) the submucosal lymph plexus extends over a long distance in 1015 a longitudinal direction before penetrating the muscle layer to enter lymph vessels in the adventitia. As a consequence of this nonsegmental lymph drainage, a primary tumor can extend for a considerable length superiorly or inferiorly in the submucosal plexus. Consequently, free tumor cells can follow the submu- 1 cosal lymphatic plexus in either direction for a long distance 3 before they pass through the muscularis and on into the regional 2 LNs. The cervical esophagus has more direct segmental lymph drainage into the regional nodes, and, as a result, lesions in this 4 6 CHAPTER 25 ESOPHAGUS AND DIAPHRAGMATIC HERNIA portion of the esophagus have less submucosal extension and a 5 more regionalized lymphatic spread. 1. Elevation of tongue The efferent lymphatics from the cervical esophagus drain 2. Posterior movement of tongue into the paratracheal and deep cervical LNs, and those from the 3. Elevation of soft palate upper thoracic esophagus empty mainly into the paratracheal 4. Elevation of hyoid LNs. Efferent lymphatics from the lower thoracic esophagus 5. Elevation of larynx drain into the subcarinal nodes and nodes in the inferior pulmo- 6. Tilting of epiglottis nary ligaments. The superior gastric nodes receive lymph not only from the abdominal portion of the esophagus, but also from Figure 25-12. Sequence of events during the oropharyngeal phase the adjacent lower thoracic segment. of swallowing. (Reproduced with permission from Zuidema GD, Orringer MB: Shackelford’s Surgery of the Alimentary Tract, 3rd ed. Vol 1. Philadelphia, PA: Elsevier/Saunders; 1991.) PHYSIOLOGY Swallowing Mechanism The act of alimentation requires the passage of food and drink gradient speeds the movement of food from the hypopharynx from the mouth into the stomach. One-third of this distance con- into the esophagus when the cricopharyngeus or upper esopha- sists of the mouth and hypopharynx, and two-thirds is made up geal sphincter relaxes. The bolus is both propelled by peristaltic by the esophagus. To comprehend the mechanics of alimenta- contraction of the posterior pharyngeal constrictors and sucked tion, it is useful to visualize the gullet as a mechanical model into the thoracic esophagus. Critical to receiving the bolus is in which the tongue and pharynx function as a piston pump the compliance of the cervical esophagus; when compliance is with three valves, and the body of the esophagus and cardia lost due to muscle pathology, dysphagia can result. The upper function as a worm-drive pump with a single valve. The three esophageal sphincter closes within 0.5 seconds of the initiation valves in the pharyngeal cylinder are the soft palate, epiglottis, of the swallow, with the immediate closing pressure reaching and cricopharyngeus. The valve of the esophageal pump is the LES. Failure of the valves or the pumps leads to abnormali- ties in swallowing—that is, difficulty in food propulsion from mouth to stomach—or regurgitation of gastric contents into the P esophagus or pharynx. C 0 Food is taken into the mouth in a variety of bite sizes, Upright position % Esophagus length where it is broken up, mixed with saliva, and lubricated. Once 20 initiated, swallowing is entirely a reflex act. When food is 40 ready for swallowing, the tongue, acting like a piston, moves Air the bolus into the posterior oropharynx and forces it into the E 60 hypopharynx (Fig. 25-12). Concomitantly with the posterior 80 movement of the tongue, the soft palate is elevated, thereby 100 closing the passage between the oropharynx and nasopharynx. DES This partitioning prevents pressure generated in the oropharynx G from being dissipated through the nose. When the soft palate is –10 –5 0 5 10 15 20 25 30 35 40 paralyzed, for example, after a cerebrovascular accident, food Pressure (mm Hg) is commonly regurgitated into the nasopharynx. During swal- Figure 25-13. Resting pressure profile of the foregut showing the lowing, the hyoid bone moves upward and anteriorly, elevating pressure differential between the atmospheric pharyngeal pressure the larynx and opening the retrolaryngeal space, bringing the (P) and the less-than-atmospheric midesophageal pressure (E) and epiglottis under the tongue (see Fig. 25-12). The backward tilt greater-than-atmospheric intragastric pressure (G), with the inter- of the epiglottis covers the opening of the larynx to prevent aspi- posed high-pressure zones of the cricopharyngeus (C) and distal ration. The entire pharyngeal part of swallowing occurs within esophageal sphincter (DES). The necessity for relaxation of the cri- 1.5 seconds. copharyngeus and DES pressure to move a bolus into the stomach During swallowing, the pressure in the hypopharynx rises is apparent. Esophageal work occurs when a bolus is pushed from abruptly, to at least 60 mmHg, due to the backward movement the midesophageal area (E), with a pressure less than atmospheric, of the tongue and contraction of the posterior pharyngeal con- into the stomach, which has a pressure greater than atmospheric strictors. A sizable pressure difference develops between the (G). (Reproduced with permission from Waters PF, DeMeester TR: hypopharyngeal pressure and the less-than-atmospheric mid- Foregut motor disorders and their surgical managemen, Med Clin esophageal or intrathoracic pressure (Fig. 25-13). This pressure North Am. 1981 Nov;65(6):1235-1268.) 1016 mm Swallow contraction, and resume its resting tone once a bolus has entered Hg Pharynx 60 the upper esophagus. Operative damage to the innervation can 50 40 interfere with laryngeal, cricopharyngeal, and upper esophageal Cricopharyngeus 30 function, and predispose the patient to aspiration. 20 10 The pharyngeal activity in swallowing initiates the esoph- 0 Seconds ageal phase. The body of the esophagus functions as a worm- 50 40 drive propulsive pump due to the helical arrangement of its 30 circular muscles, and it is responsible for transferring a bolus 20 10 of food into the stomach. The esophageal phases of swallow- 0 ing represent esophageal work done during alimentation, in 50 Seconds that food is moved into the stomach from a negative-pressure 40 environment of –6 mmHg intrathoracic pressure, to a positive- PART II Esophageal body 30 20 pressure environment of 6 mmHg intra-abdominal pressure, or 10 0 over a gradient of 12 mmHg (see Fig. 25-13). Effective and Seconds coordinated smooth muscle function in the lower one-third of 50 40 the esophagus is therefore important in pumping the food across this gradient. SPECIFIC CONSIDERATIONS 30 20 10 The peristaltic wave generates an occlusive pressure vary- 0 ing from 30 to 120 mmHg (see Fig. 25-14). The wave rises 50 Seconds to a peak in 1 second, lasts at the peak for about 0.5 seconds, 40 and then subsides in about 1.5 seconds. The whole course of 30 High pressure zone 20 the rise and fall of occlusive pressure may occupy one point in 10 Stomach 0 the esophagus for 3 to 5 seconds. The peak of a primary peri- Seconds staltic contraction initiated by a swallow (primary peristalsis) moves down the esophagus at 2 to 4 cm/s and reaches the distal Figure 25-14. Intraluminal esophageal pressures in response esophagus about 9 seconds after swallowing starts. Consecutive to swallowing. (Reproduced with permission from Waters PF, swallows produce similar primary peristaltic waves, but when DeMeester TR: Foregut motor disorders and their surgical man- the act of swallowing is rapidly repeated, the esophagus remains agemen, Med Clin North Am. 1981 Nov;65(6):1235-1268.) relaxed and the peristaltic wave occurs only after the last move- ment of the pharynx. Progress of the wave in the esophagus is caused by sequential activation of its muscles, initiated by effer- approximately twice the resting level of 30 mmHg. The postre- ent vagal nerve fibers arising in the swallowing center. laxation contraction continues down the esophagus as a peri- Continuity of the esophageal muscle is not necessary for staltic wave (Fig. 25-14). The high closing pressure and the sequential activation if the nerves are intact. If the muscles, but initiation of the peristaltic wave prevents reflux of the bolus not the nerves, are cut across, the pressure wave begins dis- from the esophagus back into the pharynx. After the peristaltic tally below the cut as it dies out at the proximal end above the wave has passed farther down the esophagus, the pressure in the cut. This allows a sleeve resection of the esophagus to be done upper esophageal sphincter returns to its resting level. without destroying its normal function. Afferent impulses from Swallowing can be started at will, or it can be reflexively receptors within the esophageal wall are not essential for prog- elicited by the stimulation of areas in the mouth and pharynx, ress of the coordinated wave. Afferent nerves, however, do go to among them the anterior and posterior tonsillar pillars or the the swallowing center from the esophagus because if the esoph- posterior lateral walls of the hypopharynx. The afferent sen- agus is distended at any point, a contraction wave begins with a sory nerves of the pharynx are the glossopharyngeal nerves forceful closure of the upper esophageal sphincter and sweeps and the superior laryngeal branches of the vagus nerves. Once down the esophagus. This secondary contraction occurs without aroused by stimuli entering via these nerves, the swallowing any movements of the mouth or pharynx. Secondary peristalsis center in the medulla coordinates the complete act of swallow- can occur as an independent local reflex to clear the esophagus ing by discharging impulses through cranial nerves V, VII, X, of ingested material left behind after the passage of the primary XI, and XII, as well as the motor neurons of C1 to C3. Dis- wave. Current studies suggest that secondary peristalsis is not charges through these nerves occur in a rather specific pattern as common as once thought. and last for approximately 0.5 seconds. Little is known about the Despite the powerful occlusive pressure, the propulsive organization of the swallowing center, except that it can trigger force of the esophagus is relatively feeble. If a subject attempts swallowing after a variety of different inputs, but the response to swallow a bolus attached by a string to a counterweight, the is always a rigidly ordered pattern of outflow. Following a cere- maximum weight that can be overcome is 5 to 10 g. Orderly brovascular accident, this coordinated outflow may be altered, contractions of the muscular wall and anchoring of the esopha- causing mild to severe abnormalities of swallowing. In more gus at its inferior end are necessary for efficient aboral propul- severe injury, swallowing can be grossly disrupted, leading to sion to occur. Loss of the inferior anchor, as occurs with a large repetitive aspiration. hiatal hernia, can lead to inefficient propulsion. The striated muscles of the cricopharyngeus and the upper The LES provides a pressure barrier between the esopha- one-third of the esophagus are activated by efferent motor fibers gus and stomach and acts as the valve on the worm-drive pump distributed through the vagus nerve and its recurrent laryngeal of the esophageal body. Although an anatomically distinct LES branches. The integrity of innervation is required for the cri- has been difficult to identify, microdissection studies show copharyngeus to relax in coordination with the pharyngeal that, in humans, the sphincter-like function is related to the  -50 Physiologic Reflux 1017 On 24-hour esophageal pH monitoring, healthy individuals have occasional episodes of gastroesophageal reflux. This physi- Gastro-esophageal ologic reflux is more common when awake and in the upright 50- muscular ring Phreno- position than during sleep in the supine position. When reflux esophageal -0 mm of gastric juice occurs, normal subjects rapidly clear the acid membrane Oblique gastric juice from the esophagus regardless of their position. Semi-circular fibers -20 There are several explanations for the observation that fibers physiologic reflux in normal subjects is more common when 0- Greater curvature wall thickness they are awake and in the upright position than during sleep in CHAPTER 25 ESOPHAGUS AND DIAPHRAGMATIC HERNIA 20- the supine position. First, reflux episodes occur in healthy vol- Lesser curvature -50 unteers primarily during transient losses of the gastroesophageal wall thickness barrier, which may be due to a relaxation of the LES or intra- gastric pressure overcoming sphincter pressure. Gastric juice can also reflux when a swallow-induced relaxation of the LES is not protected by an oncoming peristaltic wave. The average -0 mm frequency of these “unguarded moments” or of transient losses of the gastroesophageal barrier is far less while asleep and in -20 the supine position than while awake and in the upright posi- Anterior wall thickness tion. Consequently, there are fewer opportunities for reflux to Figure 25-15. Wall thickness and orientation of fibers on micro- occur in the supine position. Second, in the upright position, dissection of the cardia. At the junction of the esophageal tube there is a 12-mmHg pressure gradient between the resting, posi- and gastric pouch, there is an oblique muscular ring composed of tive intra-abdominal pressure measured in the stomach and the an increased muscle mass inside the inner muscular layer. On the most negative intrathoracic pressure measured in the esophagus lesser curve side of the cardia, the muscle fibers of the inner layer at midthoracic level. This gradient favors the flow of gastric are oriented transversely and form semicircular muscle clasps. On juice up into the thoracic esophagus when upright. The gradi- the greater curve side of the cardia, these muscle fibers form oblique ent diminishes in the supine position. Third, the LES pressure loops that encircle the distal end of the cardia and gastric fundus. in normal subjects is significantly higher in the supine posi- Both the semicircular muscle clasps and the oblique fibers of the tion than in the upright position. This is due to the apposition fundus contract in a circular manner to close the cardia. (Reproduced of the hydrostatic pressure of the abdomen to the abdominal with permission from Glenn WWL: Thoracic and Cardiovascular portion of the sphincter when supine. In the upright position, Surgery, 4th ed. Norwalk, CT: Appleton-Century-Crofts; 1983.) the abdominal pressure surrounding the sphincter is negative compared with atmospheric pressure, and, as expected, the abdominal pressure gradually increases the more caudally it is measured. This pressure gradient tends to move the gastric con- architecture of the muscle fibers at the junction of the esoph- tents toward the cardia and encourages the occurrence of reflux ageal tube with the gastric pouch (Fig. 25-15). The sphincter into the esophagus when the individual is upright. In contrast, actively remains closed to prevent reflux of gastric contents into in the supine position, the gastroesophageal pressure gradient the esophagus and opens by a relaxation that coincides with a diminishes, and the abdominal hydrostatic pressure under the pharyngeal swallow (see Fig. 25-14). The LES pressure returns diaphragm increases, causing an increase in sphincter pressure to its resting level after the peristaltic wave has passed through and a more competent cardia. the esophagus. Consequently, reflux of gastric juice that may The LES has intrinsic myogenic tone, which is modu- occur through the open valve during a swallow is cleared back lated by neural and hormonal mechanisms. α-Adrenergic neu- into the stomach. rotransmitters or β-blockers stimulate the LES, and α-blockers If the pharyngeal swallow does not initiate a peristaltic con- and β-stimulants decrease its pressure. It is not clear to what traction, then the coincident relaxation of the LES is unguarded extent cholinergic nerve activity controls LES pressure. The and reflux of gastric juice can occur. This may be an explanation vagus nerve carries both excitatory and inhibitory fibers to the for the observation of spontaneous lower esophageal relaxation, esophagus and sphincter. The hormones gastrin and motilin thought by some to be a causative factor in gastroesophageal have been shown to increase LES pressure; and cholecystokinin, reflux disease (GERD). The power of the worm-drive pump of estrogen, glucagon, progesterone, somatostatin, and secretin the esophageal body is insufficient to force open a valve that decrease LES pressure. The peptides bombesin, l-enkephalin, does not relax. In dogs, a bilateral cervical parasympathetic and substance P increase LES pressure; and calcitonin gene- blockade abolishes the relaxation of the LES that occurs with related peptide, gastric inhibitory peptide, neuropeptide Y, and pharyngeal swallowing or distention of the esophagus. Conse- vasoactive intestinal polypeptide decrease LES pressure. Some quently, vagal function appears to be important in coordinating pharmacologic agents such as antacids, cholinergics, agonists, the relaxation of the LES with esophageal contraction. domperidone, metoclopramide, and prostaglandin F2 are known The antireflux mechanism in human beings is composed to increase LES pressure; and anticholinergics, barbiturates, cal- of three components: a mechanically effective LES, efficient cium channel blockers, caffeine, diazepam, dopamine, meperi- esophageal clearance, and an adequately functioning gastric dine, prostaglandin E1 and E2, and theophylline decrease LES reservoir. A defect of any one of these three components can pressure. Peppermint, chocolate, coffee, ethanol, and fat are all lead to increased esophageal exposure to gastric juice and the associated with decreased LES pressure and may be responsible development of mucosal injury. for esophageal symptoms after a sumptuous meal. 1018 ASSESSMENT OF ESOPHAGEAL FUNCTION to confirm the presence of IM, and to evaluate the Barrett’s epi- thelium for dysplastic changes. BE is susceptible to ulceration, A thorough understanding of the patient’s underlying anatomic bleeding, stricture formation, and, most important, malignant and functional deficits before making therapeutic decisions is degeneration. The earliest sign of the latter is high grade dys- fundamental to the successful treatment of esophageal disease. plasia or intramucosal adenocarcinoma (see Fig. 25-16). These The diagnostic tests, as presently used, may be divided into four dysplastic changes have a patchy distribution, so a minimum 1 broad groups: (a) tests to detect structural abnormalities of the esophagus; (b) tests to detect functional abnormalities of four biopsy samples spaced 2 cm apart should be taken from the Barrett’s-lined portion of the esophagus. Changes seen in of the esophagus; (c) tests to detect increased esophageal expo- one biopsy are significant. Nishimaki has determined that the sure to gastric juice; and (d) tests of duodenogastric function as tumors occur in an area of specialized columnar epithelium near they relate to esophageal disease. the squamocolumnar junction in 85% of patients, and within Tests to Detect Structural Abnormalities PART II 2 cm of the squamocolumnar junction in virtually all patients. Endoscopic Evaluation. The first diagnostic test in patients Particular attention should be focused on this area in patients with suspected esophageal disease is usually upper gastrointesti- suspected of harboring a carcinoma. nal endoscopy. This allows assessment and biopsy of the mucosa Abnormalities of the gastroesophageal flap valve can be of the stomach and the esophagus, as well as the diagnosis and visualized by retroflexion of the endoscope. Hill has graded the appearance of the gastroesophageal valve from I to IV according SPECIFIC CONSIDERATIONS assessment of obstructing lesions in the upper gastrointestinal tract. In any patient complaining of dysphagia, esophagoscopy to the degree of unfolding or deterioration of the normal valve is indicated, even in the face of a normal radiographic study. architecture (Fig. 25-17). The appearance of the valve correlates For the initial endoscopic assessment, the flexible fiber- with the presence of increased esophageal acid exposure, occur- optic esophagoscope is the instrument of choice because of its ring predominantly in patients with grade III and IV valves. technical ease, patient acceptance, and the ability to simultane- A hiatal hernia is endoscopically confirmed by finding a ously assess the stomach and duodenum. Rigid endoscopy is pouch lined with gastric rugal folds lying 2 cm or more above now only rarely required, mainly for the disimpaction of diffi- the margins of the diaphragmatic crura, identified by having the cult foreign bodies impacted in the esophagus, and few individ- patient sniff. A hernia is best demonstrated with the stomach uals now have the skill set and experience to use this equipment. fully insufflated and the gastroesophageal junction observed When GERD is the suspected diagnosis, particular atten- with a retroflexed endoscope. A prominent sliding hiatal hernia tion should be paid to detecting the presence of esophagitis and frequently is associated with increased esophageal exposure to Barrett’s columnar-lined esophagus (CLE). When endoscopic gastric juice. When a paraesophageal hernia (PEH) is observed, esophagitis is seen, severity and the length of esophagitis particular attention is taken to exclude gastric (Cameron’s) involved are recorded. Whilst many different grading systems ulcers or gastritis within the pouch. The intragastric retroflex or have been proposed, the commonest system now in use is the J maneuver is important in evaluating the full circumference of Los Angeles (LA) grading system. In this system, mild esopha- the mucosal lining of the herniated stomach. gitis is classified LA grade A or B—one or more erosions lim- When an esophageal diverticulum is seen, it should ited to the mucosal fold(s) and either less than or greater than be carefully explored with the flexible endoscope to exclude 5 mm in longitudinal extent respectively (Fig. 25-16). More ulceration or neoplasia. When a submucosal mass is identified, severe esophagitis is classified LA grade C or D. In grade C, biopsy specimens are usually not performed. At the time of sur- erosions extend over the mucosal folds but over less than three- gical resection, a submucosal leiomyoma or reduplication cyst quarters of the esophageal circumference; in grade D, confluent can generally be dissected away from the intact mucosa, but if erosions extend across more than three-quarters of the esopha- a biopsy sample is taken, the mucosa may become fixed to the geal circumference. In addition to these grades, more severe underlying abnormality. This complicates the surgical dissec- damage can lead to the formation of a stricture. A stricture’s tion by increasing the risk of mucosal perforation. Endoscopic severity can be assessed by the ease of passing a standard endo- ultrasound provides a better method for evaluating these lesions. scope. When a stricture is observed, the severity of the esopha- Radiographic Evaluation. Barium swallow evaluation is under- gitis above it should be recorded. The absence of esophagitis taken selectively to assess anatomy and motility. The anatomy of above a stricture suggests the possibility of a chemical-induced large hiatal hernias is more clearly demonstrated by contrast radi- injury or a neoplasm as a cause. The latter should always be ology than endoscopy, and the presence of coordinated esopha- considered and is ruled out only by evaluation of a tissue biopsy geal peristalsis can be determined by observing several individual of adequate size. It should be remembered that gastroesophageal swallows of barium traversing the entire length of the organ, reflux is not always associated with visible mucosal abnormali- with the patient in the horizontal position. Hiatal hernias are best ties, and patients can experience significant reflux symptoms, demonstrated with the patient prone because the increased intra- despite an apparently normal endoscopy examination. abdominal pressure produced in this position promotes displace- Barrett’s esophagus (BE) is a condition in which the tubu- ment of the esophagogastric junction above the diaphragm. To lar esophagus is lined with columnar epithelium, as opposed to detect lower esophageal narrowing, such as rings and strictures, the normal squamous epithelium (see Fig. 25-16). Histologi- fully distended views of the esophagogastric region are crucial. cally, it appears as intestinal metaplasia (IM). It is suspected at The density of the barium used to study the esophagus can poten- endoscopy when there is difficulty in visualizing the squamoco- tially affect the accuracy of the examination. Esophageal disorders lumnar junction at its normal location, and by the appearance of shown clearly by a full-column technique include circumferential a redder, salmon-colored mucosa in the lower esophagus, with carcinomas, peptic strictures, large esophageal ulcers, and hia- a clearly visible line of demarcation at the top of the Barrett’s tal hernias. A small hiatal hernia is usually not associated with esophagus segment. Its presence is confirmed by biopsy. Mul- significant symptoms or illness, and its presence is an irrelevant tiple biopsy specimens should be taken in a cephalad direction finding unless the hiatal hernia is large (Fig. 25-18) or the hernia  1019 CHAPTER 25 ESOPHAGUS AND DIAPHRAGMATIC HERNIA A B C D Figure 25-16. Complications of reflux disease as seen on endoscopy. A. Linear erosions of LA grade B esophagitis. B. Uncomplicated Barrett’s mucosa. C. High-grade dysplasia in Barrett’s mucosa. D. Early adenocarcinoma arising in Barrett’s mucosa. is of the paraesophageal variety. Lesions extrinsic but adjacent to A gastric or duodenal ulcer, partially obstructing gastric neoplasm, the esophagus can be reliably detected by the full-column tech- or scarred duodenum and pylorus may contribute significantly to nique if they contact the distended esophageal wall. Conversely, symptoms otherwise attributable to an esophageal abnormality. a number of important disorders may go undetected if this is the When a patient’s complaints include dysphagia and no sole technique used to examine the esophagus. These include obstructing lesion is seen on the barium swallow, it is useful to small esophageal neoplasms, mild esophagitis, and esophageal have the patient swallow a barium-impregnated marshmallow, a varices. Thus, the full-column technique should be supplemented barium-soaked piece of bread, or a hamburger mixed with bar- with mucosal relief or double-contrast films to enhance detection ium. This test may bring out a functional disturbance in esopha- of these smaller or more subtle lesions. geal transport that can be missed when liquid barium is used. Motion-recording techniques greatly aid in evaluating functional disorders of the pharyngoesophageal and esophageal Tests to Detect Functional Abnormalities phases of swallowing. The technique and indications for cine- In many patients with symptoms of an esophageal disorder, and videoradiography will be discussed in the section entitled standard radiographic and endoscopic evaluation fails to dem- “Video- and Cineradiography,” as they are more useful to evalu- onstrate a structural abnormality. In these situations, esophageal ate function and seldom used to detect structural abnormalities. function tests are necessary to identify a functional disorder. The radiographic assessment of the esophagus is not com- Esophageal Motility. Esophageal motility is a widely used plete unless the entire stomach and duodenum have been examined. technique to examine the motor function of the esophagus and 1020 PART II A SPECIFIC CONSIDERATIONS B C Figure 25-17. A. Grade I flap valve appearance. Note the ridge of tissue that is closely approximated to the shaft of the retroflexed endoscope. It extends 3 to 4 cm along the lesser curve. B. Grade II flap valve appearance. The ridge is slightly less well defined than in grade I and it opens rarely with respiration and closes promptly. C. Grade III flap valve appearance. The ridge is barely present, and there is often failure to close around the endoscope. It is nearly always accompanied by a hiatal hernia. D. Grade IV flap valve appearance. There is no muscular ridge at all. The gastroesophageal valve stays open all the time, and squamous epithelium can often be seen from the retroflexed position. A hiatal hernia is always present. (Reproduced with permission from Hill LD, Kozarek RA, Kraemer SJ, et al: The gastroesophageal flap valve: in vitro and in vivo observations, Gastrointest Endosc. 1996 Nov;44(5):541-547.)  1021 CHAPTER 25 ESOPHAGUS AND DIAPHRAGMATIC HERNIA D Figure 25-17. (Continued ) its sphincters. The esophageal motility study (EMS) is indicated guiding selection of the appropriate procedure based upon the whenever a motor abnormality of the esophagus is suspected on patient’s underlying esophageal function and excluding patients the basis of complaints of dysphagia, odynophagia, or noncar- with achalasia who can be misdiagnosed with gastroesophageal diac chest pain, and the barium swallow or endoscopy does not reflux when clinical and endoscopic parameters alone are used show a clear structural abnormality. EMS is particularly neces- for diagnosis. sary to confirm the diagnosis of specific primary esophageal EMS is performed using electronic, pressure-sensitive motility disorders (i.e., achalasia, diffuse esophageal spasm transducers located within the catheter, or water-perfused cath- [DES], nutcracker esophagus, and hypertensive LES). It also eters with lateral side holes attached to transducers outside the identifies nonspecific esophageal motility abnormalities and body. The traditional water perfused catheter has largely been motility disorders secondary to systemic disease such as sclero- replaced by high resolution motility (HRM), but knowledge of derma, dermatomyositis, polymyositis, or mixed connective tis- traditional methods of assessing esophageal motility is helpful sue disease. In patients with symptomatic GERD, manometry for understanding esophageal physiology. of the esophageal body can identify a mechanically defective As the pressure-sensitive station is brought across the gas- LES and evaluate the adequacy of esophageal peristalsis and troesophageal junction (GEJ), a rise in pressure above the gas- contraction amplitude. EMS has become an essential tool in the tric baseline signals the beginning of the LES. The respiratory preoperative evaluation of patients before antireflux surgery, inversion point is identified when the positive excursions that occur in the abdominal cavity with breathing change to negative deflections in the thorax. The respiratory inversion point serves as a reference point at which the amplitude of LES pressure and the length of the sphincter exposed to abdominal pressure are measured. As the pressure-sensitive station is withdrawn into the body of the esophagus, the upper border of the LES is identified by the drop in pressure to the esophageal baseline. From these measurements, the pressure, abdominal length, and overall length of the sphincter are determined (Fig. 25-19). To Overall length Gastric baseline pressure Pressure 43 42 41 40 39 38 37 cm 10 sec RIP Esophageal baseline Abdominal length pressure RIP = Respiratory inversion point Figure 25-19. Manometric pressure profile of the lower esophageal sphincter. The distances are measured from the nares. (Reproduced Figure 25-18. Radiogram of an intrathoracic stomach. This with permission from Zaninotto G, DeMeester TR, Schwizer W, is the end stage of a large hiatal hernia, regardless of its initial et al: The lower esophageal sphincter in health and disease, Am J classification. Surg. 1988 Jan;155(1):104-11.) 1022 LP foregut disorder. A mechanically defective sphincter is identified P by having one or more of the following characteristics: an 0 average LES pressure of