Surgical Anatomy of Paraesophageal Hernias
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Surgical Anatomy of Paraesophageal Hernias Roman V. Petrov, MD, PhDa,b,*, Stacey Su, MDb, Charles T. Bakhos, MD, MSa, Abbas El-Sayed Abbas, MD, MSa,b KEYWORDS Hiatal hernia Paraesophageal hernia Surgical anatomy Esophageal hiatus Gastroesophageal junction KEY POINTS Incidence of paraesophageal hernias is increasing owing to the increased proportion of advanced age patients and clinicians’ awareness. Minimally invasive, including robotic, surgical techniques are increasing in popularity and produce excellent results. Thorough understanding of anatomic relationship in paraesophageal hernias is required for suc- cessful surgical repair regardless of the surgical approach. NORMAL ESOPHAGEAL ANATOMY enters the chest through the thoracic inlet and is located initially in the superior and then the poste- The esophagus is a tubular organ, approximately rior mediastinum. The midesophagus deviates 25 cm long, which connects the hypopharynx to slightly to the right, usually passing behind the the stomach. Along its course, it traverses 3 left mainstem bronchus and pericardium anterior body areas: the neck, the chest, and the abdomen to the prevertebral fascia of T1 though T10 verte- (Fig. 1A). Accordingly, it is subdivided into 3 bral bodies. Both vagus nerves accompany the anatomic segments: cervical, thoracic, and esophagus throughout its course on each side. abdominal. The descending thoracic aorta is located posteri- The cervical segment of the esophagus starts at orly and to the left, whereas the mediastinal pleura the hypopharynx, from which it is separated by the drapes over both sides of the esophagus. upper esophageal sphincter, at the level of the The abdominal esophagus is a short segment of sixth cervical vertebra. The cervical esophagus ex- the organ, extending from the diaphragmatic hia- tends down to the level of suprasternal notch. It is tus at the level of T10 to the gastric cardia at the located directly behind and partially to the left of level of T11. After passing through the hiatus, the the trachea, in front of C6 and C7 vertebral bodies. abdominal esophagus deviates to the left and en- Laterally, the esophagus is surrounded by the ters the stomach, forming the gastroesophageal lower poles of the thyroid gland and the carotid junction (GEJ). The descending aorta is located sheaths. On the left side, the termination of the posterior to the GEJ, and the inferior vena cava thoracic duct can be found entering the venous is posterior and to the right. It is covered anteriorly angle at the junction of the left internal jugular by the left lobe of the liver. and subclavian veins. In cross-section, the esophagus has 3 layers The thoracic esophagus extends from the (mucosa, submucosa, and muscularis propria) suprasternal notch to the diaphragmatic hiatus. It Dr. Abbas received honoraria from Boston Scientific and Intuitive. No disclosures for other authors. a Department of Thoracic Medicine and Surgery, Division of Thoracic Surgery, Lewis Katz School of Medicine at Temple University, 3401 North Broad Street C-501, Philadelphia, PA 19140, USA; b Department of Surgical Oncology, Fox Chase Cancer Center, 333 Cottman Avenue C-312, Philadelphia, PA 19111, USA * Corresponding author. Department of Thoracic Medicine and Surgery, Division of Thoracic Surgery, Lewis Katz School of Medicine at Temple University, 3401 North Broad Street C-501, Philadelphia, PA 19140. E-mail address: [email protected] Thorac Surg Clin 29 (2019) 359–368 https://doi.org/10.1016/j.thorsurg.2019.07.008 1547-4127/19/Ó 2019 Elsevier Inc. All rights reserved. thoracic.theclinics.com Downloaded for Anonymous User (n/a) at Second Military Medical University from ClinicalKey.com by Elsevier on February 15, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. 360 Petrov et al Fig. 1. Anatomy of the esophagus and GEJ. (A) Position of the esoph- agus, with its locations in the neck, chest, and abdomen. (B) Diaphragm, esophageal hiatus and gastroesopha- geal junction. surrounded by the adventitia. After crossing nodes. There is significant overlap in the lymphatic through the hiatus, the esophagus is enveloped drainage between these segments. by the visceral peritoneum, forming a serosa. The The intrinsic nervous system is formed by the muscularis propria, formed in the proximal third submucosal and the intramuscular neural plexi. of the esophagus by striated muscle, is replaced Innervation to the esophagus is supplied by both by smooth muscle in the distal esophagus. It con- vagus nerves, providing the parasympathetic con- sists of an inner circular layer and outer longitudi- trol of esophageal wall motility, the esophageal nal layer. The circular muscle fibers are arranged sphincters, and glandular secretions. Sympathetic in a helical fashion, sometimes giving rise to a innervation is provided by the sympathetic chains corkscrew appearance in many motility and is mostly responsible for vasomotor effects disorders.1 and pain sensation. The vagus nerves arise in the The blood supply to the esophagus is segmental. medulla oblongata as the tenth cranial nerves The cervical esophagus is supplied by branches of and after exiting the skull base run on each side the inferior thyroid arteries, whereas the thoracic of the esophagus. They enter the chest via the esophagus is supplied by small aortoesophageal thoracic inlet and travel caudally along the esoph- arteries, in addition to branches from the bronchial agus to the hiatus. Because of the embryologic and superior phrenic arteries. The abdominal clock-wise rotation of the lower foregut in the esophagus receives blood supply from branches abdomen, the left vagus nerve becomes anterior, of the left gastric artery, the splenic artery, and whereas the right vagus nerve lies posteriorly.1,2 the left inferior phrenic artery. Venous drainage forms a submucosal plexus, draining the cervical STOMACH segment through the inferior thyroid veins and the thoracic esophagus through the azygos system The stomach is a J-shaped saccular expansion of into the superior vena cava. The lower thoracic the foregut, serving as a reservoir for the ingested and abdominal esophagus is drained into the portal food at the beginning of the digestive process system via the gastric veins. In cases of portal hy- (Fig. 2A). It receives the food bolus from the pertension, these lower esophageal veins can esophagus, via the GEJ, below the esophageal hi- dilate, forming esophageal varices. atus. It transitions into the duodenum at the pylo- The lymphatic drainage also starts at the sub- rus. On the right, the concave edge of the mucosal plexus, forming lymphatic channels that stomach is termed the lesser curvature, whereas drain into the regional lymph nodes. The deep cer- the left convex edge is called the greater curva- vical nodes receive lymph flow from the cervical ture. The peritoneal reflections, connecting the and the upper thoracic esophagus. The paraeso- lesser curvature to the liver, form the lesser omen- phageal lymph nodes of the superior and posterior tum, also called the gastrohepatic ligament. It con- mediastinum drain the thoracic segment. The tains branches of the left and right gastric arteries. lower thoracic segment and the abdominal esoph- Peritoneal reflections on the greater curvature side agus drain into the celiac and perigastric lymph form the greater omentum and are subdivided by Downloaded for Anonymous User (n/a) at Second Military Medical University from ClinicalKey.com by Elsevier on February 15, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. Surgical Anatomy of Paraesophageal Hernias 361 Fig. 2. Types of paraesophageal hernias. (A) Normal anatomy of the GEJ. (B) Type I (sliding) hiatal hernia. (C) Type II paraesophageal hernia. The GEJ is retained at the hiatus and fundus has herniated into the mediastinum through a localized defect at the phrenoesophageal membrane, with formation of peritoneal hernia sac. (D) Type III paraesophageal hernia (herniation of the GEJ and various degrees of the gastric fundus and the body into posterior mediastinum, with formation of the peritoneal hernia sac). (E) Type III paraesophageal hernia with totally intrathoracic stomach. (F) Type IV paraesophageal hernia with herniation of the other intraabdomi- nal organs in addition to the GEJ and various degrees of the gastric fundus and the body with formation of the hernia sac. the site of the attachment into gastrophrenic, gas- diaphragm, providing a major contribution to the trosplenic, and gastrocolic ligaments. They respiratory cycle. Several important structures contain both right and left gastroepiploic branches cross the diaphragm. The inferior vena cava enters from the pancreaticoduodenal and the splenic ar- the chest through the opening in the central teries that form an arch along the antrum and the tendon and is accompanied by small branches of body of the stomach about a centimeter lateral right phrenic nerve. The aorta with the accompa- to the stomach wall. The fundus is directly sup- nying thoracic duct traverses the diaphragm plied by the branches of the short gastric vessels. through aortic hiatus between the diaphragmatic crura. The splanchnic nerves, sympathetic chains, DIAPHRAGM hemiazygos vein, and internal thoracic artery travel through an additional minor opening in the dia- The diaphragm is a complex flat dome-shaped phragm. The esophagus with both vagus nerves fibromuscular structure that separates the chest traverses the diaphragm through the esophageal from the abdomen. It has a central fibrous tendon hiatus. and muscular fibers peripherally, attaching to the lumbar vertebrae in the back, lower 6 ribs on THE ESOPHAGEAL HIATUS both sides, and xyphoid process anteriorly. Contraction of the muscular fibers results in the The esophageal hiatus is a slit-like opening in the vertical displacement of the fibrous center of the diaphragm that is formed by the thickened Downloaded for Anonymous User (n/a) at Second Military Medical University from ClinicalKey.com by Elsevier on February 15, 2020. For personal use only. No other uses without permission.