Theresa W. Fossum, DVM, MS, PhD, DACVS
Texas A&M University College of Veterinary Medicine, College Station, TX, USA
Surgery of the Esophagus
Esophagotomy is an incision into the esophageal lumen; esophagectomy is partial resection of the esophagus. Esophagostomy is the creation of an opening in the esophagus for placement of a feeding tube. Regurgitation is the passive expulsion of undigested food or fluid from the esophagus. Vomiting is a centrally mediated reflex that causes expulsion of food or fluid from the stomach or duodenum or both.
Abnormalities of the cervical esophagus are approached using a ventral midline cervical incision. Thoracic esophageal abnormalities at the base of the heart are approached using a right lateral thoracotomy and those cranial or caudal to the heart with a left cranial or caudal thoracotomy. The abdominal esophagus is approached through a ventral midline celiotomy. Hair should be clipped from the entire ventral cervical area for surgery of the cervical esophagus and from the entire hemithorax for approaches to the thoracic esophagus. The skin should be aseptically prepared for surgery. Atraumatic meticulous technique most be employed to ensure rapid healing without dehiscence or stricture.
Approach to the Cervical Esophagus
Position the patient in dorsal recumbency. Incise the skin on the midline, beginning at the larynx and extending caudally to the manubrium. Incise and retract the platysma muscle and subcutaneous tissues. Separate the paired sternohyoid muscles along the midline to expose the underlying trachea. Retract the thyroideum vein with the sternohyoid muscle or ligate it. If access to the caudal cervical esophagus is needed, separate and retract the sternocephalic muscles. Retract the trachea to the right to expose the adjacent anatomic structures, including the esophagus, the thyroid gland, the cranial and caudal thyroid vessels, the recurrent laryngeal nerve, and the carotid sheath (vagosympathetic trunk, carotid artery, and internal jugular vein). Pass a stomach tube or esophageal stethoscope to facilitate identification of the esophagus and lesion. After completing the definitive procedure, lavage the surgical site with warm sterile saline and return the trachea to its normal position. Close the incision by apposing the sternohyoid muscles using absorbable suture (3-0 or 4-0) in a simple continuous pattern. Appose subcutaneous tissues in a simple continuous pattern with 3-0 or 4-0 absorbable suture. Use nonabsorbable suture (3-0 or 4-0 monofilament) and an appositional suture pattern to appose the skin.
Approach to the Cranial Thoracic Esophagus via a Lateral Intercostal Thoracotomy
Position the patient in right lateral recumbency over a rolled towel placed perpendicular to the long axis of the body. Choose the appropriate intercostal space incision based on the radiographic location of the abnormality. Most abnormalities cranial to the base of the heart can be accessed through an incision in the left third or fourth intercostal space. Identify the esophagus in the mediastinum dorsal to the brachiocephalic trunk. Identification may be aided by passage of a stomach tube or by palpating the abnormality. Dissect the mediastinal pleura overlapping the esophagus to just above and below the proposed surgical site. Preserve the branch of the internal thoracic vein and the costocervical vein, which cross the cranial esophagus.
Approach to the Esophagus at the Heart Base via a Right Lateral Thoracotomy
The approach is the same as that for the cranial esophagus except that the incision is made through the right fourth or fifth intercostal space. Identify the esophagus, located just dorsal to the trachea in the mediastinum. Dissect and retract the azygous vein from the esophagus to allow adequate exposure. Ligate the azygous vein if necessary to adequately expose the esophagus. Closure is the same as for cranial thoracotomy.
Approach to the Caudal Esophagus via a Caudal Lateral Thoracotomy
Position the patient in lateral recumbency as described above for cranial lateral thoracotomy. Perform a caudal lateral thoracotomy.
Although the caudal esophagus can be approached through an incision in either the left or right eighth or ninth intercostal space, the left ninth space is preferred.
Expose the caudal esophagus by transecting the pulmonary ligament and packing the caudal lung lobes cranially. Identify the esophagus, which is just ventral to the aorta. Identify the dorsal and ventral vagal nerve branches on the lateral aspect of the esophagus and protect them.
Pack off the esophagus from the remainder of the field with moistened laparotomy pads. Suction material from the cranial esophagus before making the esophagotomy incision to minimize contamination of the surgical site. If ingesta and secretions have not been completely suctioned, occlude the lumen cranial and caudal to the proposed esophagotomy site with fingers or noncrushing forceps. Place stay sutures adjacent to the proposed incision site to stabilize, aid manipulation, and avoid trauma to the esophageal edges. Make a stab incision into the lumen of the esophagus and extend the incision longitudinally as necessary to remove the foreign body or observe the lumen. Make the incision over the foreign body if the esophageal wall appears normal. If the wall appears compromised, make the incision caudal to the lesion or foreign body. Remove foreign bodies with forceps, taking care to avoid further esophageal trauma (tearing or perforation). Examine the esophageal lumen. Obtain culture specimens from necrotic and perforated areas. Debride and close perforations surrounded by healthy tissue that involve less than one fourth the circumference of the esophagus. Identify large necrotic areas or extensive perforations and perform a resection and anastomosis (see below).
Esophagotomy incisions may be closed with a one-or two-layer closure. A two-layer simple interrupted closure results in greater immediate wound strength, better tissue apposition, and improved healing after esophagotomy but takes longer to perform than single-layer techniques.
Place each suture approximately 2 mm from the edge and 2 mm apart. Incorporate the mucosa and submucosa in the first layer of a two-layer simple interrupted closure. Place sutures so that the knots are within the esophageal lumen. Incorporate the adventitia, muscularis, and submucosa in the second layer of sutures with the knots tied extraluminally. When a one-layer closure is used, pass each suture through all layers of the esophageal wall and tie the knots on the extraluminal surface. Check closure integrity by occluding the lumen, injecting saline, applying pressure, and observing for leakage between sutures.
Esophagectomy is performed to remove devitalized or diseased esophageal segments. Benign strictures should be dilated endoscopically if possible, with surgery reserved as a salvage procedure. Periesophageal tissues must be dissected from around the abnormal area to allow resection of diseased tissue and mobilization of normal esophagus; however, extensive dissection should be avoided to preserve vasculature. Excessive tension along the anastomosis may cause dehiscence. Although 20% to 50% of the esophagus has been resected and primarily anastomosed without tension relieving techniques, resection of more than 3 to 5 cm risks anastomotic dehiscence. Partial myotomy is recommended to relieve anastomotic tension when resecting large segments of esophagus. Circumferential myotomy is a partial thickness myotomy through the longitudinal muscle layers 2 to 3 cm cranial and caudal to the anastomosis. The inner circular muscle layers are not incised to avoid damaging the submucosal blood supply. Injection of saline into the muscularis may aid identification of the different muscle layers. The myotomy gap heals by second intention without stricture or dilatation. Mobilizing the stomach cranially through an enlarged esophageal hiatus can also help reduce tension across the anastomosis. Other tension relieving techniques include interruption of the phrenic nerve and placement of "pexy" sutures between the esophagus and the prevertebral fascia. Esophageal replacement may be necessary if segments of more than 3 to 5 cm are resected. Many replacement techniques have been described, including microvascular anastomosis of the colon or small intestine to the esophagus, gastric tubes, skin tubes, and various prostheses. Replacement of the esophagus requires specialized training, techniques, and equipment.
For esophagectomy, occlude and stabilize the esophagus with fingers (scissor action of middle and index fingers) or noncrushing forceps. Resect the diseased portion of the esophagus. Suction debris from the lumen of the remaining esophagus. Place three equally spaced stay sutures at each end of the remaining esophagus to facilitate gentle handling of the esophagus and help maintain apposition and alignment of the transected ends. Bring the esophageal ends into apposition with the stay sutures and suture the ends together using a one- or two-layer closure as described for esophagotomy. Place sutures in the contralateral (far) wall first and then in the more accessible ipsilateral (near) wall. When using a two-layer closure, appose the esophagus in the following four steps: 1) appose the adventitia and muscularis of the contralateral wall around approximately one half of the esophageal circumference; 2) appose the mucosa and submucosa of the contralateral wall, B); 3) appose the mucosa and submucosa of the ipsilateral wall; and 4) appose the adventitia and muscularis of the ipsilateral wall. Check the integrity of the closure by occluding the lumen, injecting saline, applying pressure, and observing for leakage between sutures.
An end-to-end circular stapling device may reduce operating time and contamination of the surgical field, but this technique may have a greater potential for stricture formation.
Place a purse-string suture in the cranial esophageal remnant. Insert the anvil and tie the purse string around the instrument shaft. Place a second purse-string suture around the distal resection site and secure it. Appose the esophageal ends by tightening the stapler's wing nut. Activate the instrument and then remove it with a rotating motion. Close the access incision for placement of the stapling device with a linear stapler.
Feeding tubes placed in the midcervical esophagus are associated with fewer complications than pharyngostomy or nasogastric feeding tubes. Tubes are positioned rostral to the gastroesophageal junction to reduce gastroesophageal reflux. Ostomy wounds heal by second intention after removal of the tube without evidence of stricture or esophagocutaneous fistula.
Surgery of the Stomach
Gastric surgery is commonly performed to remove foreign bodies and to correct gastric dilatation-volvulus. Gastric ulceration or erosion, neoplasia, and benign gastric outflow obstruction are less common indications. Gastric disease may cause vomiting (intermittent or profuse and continuous) or just anorexia. Dehydration and hypokalemia are common in vomiting animals and should be corrected before induction of anesthesia. Alkalosis may occur secondary to gastric fluid loss; however, metabolic acidosis may also be seen. Hematemesis may indicate gastric erosion or ulceration or coagulation abnormalities. Peritonitis arising from perforation of the stomach caused by necrosis or ulceration often is lethal if not treated promptly and aggressively. Aspiration pneumonia or esophagitis may also occur in vomiting animals. If possible, severe aspiration pneumonia should be treated before induction of anesthesia for gastric surgery.
The most common indication for gastrotomy in dogs and cats is removal of a foreign body. Make a ventral midline abdominal incision from the xiphoid to the pubis. Use Balfour retractors to retract the abdominal wall and provide adequate exposure of the gastrointestinal tract. Inspect the entire abdominal contents before incising the stomach. To reduce contamination, isolate the stomach from remaining abdominal contents with moistened laparotomy sponges. Place stay sutures to assist in manipulation of the stomach and help prevent spillage of gastric contents. Make the gastric incision in a hypovascular area of the ventral aspect of the stomach, between the greater and lesser curvatures. Make sure the incision is not near the pylorus, or closure of the incision may cause excessive tissue to be enfolded into the gastric lumen, resulting in outflow obstruction. Make a stab incision into the gastric lumen with a scalpel and enlarge the incision with Metzenbaum scissors. Use suction to aspirate gastric contents and reduce spillage. Close the stomach with 2-0 or 3-0 absorbable suture material (e.g., polydioxanone, polyglyconate) in a two-layer inverting seromuscular pattern. Include serosa, muscularis, and submucosa in the first layer, using a Cushing or simple continuous pattern, then follow it with a Lembert or Cushing pattern that incorporates the serosal and muscularis layers. As an alternative, close the mucosa in a simple continuous suture pattern as a separate layer to reduce postoperative bleeding. Before closing the abdominal incision, substitute sterile instruments and gloves for those contaminated by gastric contents. Whenever you remove a gastric foreign body, be sure to check the entire intestinal tract for additional material that could cause an intestinal obstruction.