Surgical diseases of the esophagus

The pathology and pathogenesis of experimental severe acute respiratory syndrome and influenza in animal models

Respiratory viruses that emerge in the human population may cause high morbidity and mortality, as well as concern about pandemic spread. Examples are severe acute respiratory syndrome coronavirus (SARS-CoV) and novel variants of influenza A virus, such as H5N1 and pandemic H1N1. Different animal models are used to develop therapeutic and preventive measures against such viruses, but it is not clear which are most suitable. Therefore, this review compares animal models of SARS and influenza, with an emphasis on non-human primates, ferrets and cats. Firstly, the pathology and pathogenesis of SARS and influenza are compared. Both diseases are similar in that they affect mainly the respiratory tract and cause inflammation and necrosis centred on the pulmonary alveoli and bronchioles. Important differences are the presence of multinucleated giant cells and intra-alveolar fibrosis in SARS and more fulminant necrotizing and haemorrhagic pneumonia in H5N1 influenza. Secondly, the pathology and pathogenesis of SARS and influenza in man and experimental animals are compared. Host species, host age, route of inoculation, location of sampling and timing of sampling are important to design an animal model that most closely mimics human disease. The design of appropriate animal models requires an accurate pathological description of human cases, as well as a good understanding of the effect of experimental variables on disease outcome.

Esophagectomy and substitution of the thoracic esophagus in dogs

PURPOSE

To evaluate a technique to remove the thoracic esophagus without thoracotomy and two methods for thoracic esophageal replacement in dogs.

METHODS

27 ex-vivo dogs were divided into three groups in order to evaluate: G1 - total thoracic esophagectomy by the everting stripping method; G2 - total thoracic esophagectomy and esophageal substitution using the whole stomach; G3 - total thoracic esophagectomy and esophageal substitution using fundus rotation gastroplasty. After esophageal resection in G1, the integrity of the intrathoracic route was evaluated by endoscopy and tested with 1% methylene blue solution.

RESULTS

Visceral pleural rupture was observed in all animals. However, this intrathoracic route made it possible to bring both esophagus substitutes (G2 and G3) to be anastomosed to the cut end of the cervical esophagus.

CONCLUSIONS

Thoracic esophageal substitution using the whole stomach showed less anastomotic tension and was less technically demanding than the fundus rotation gastroplasty method. The ex-vivo results support further studies to validate the techniques in clinical cases.

Chronic oesophageal foreign body in a cat

An 11-year-old cat was presented with an approximately 2-month history of dysphagia, intermittent regurgitation and weight loss. An oesophageal foreign body was identified on plain radiographs, and an oesophagotomy was performed to remove a large V-shaped bone from the caudal cervical oesophagus. A gastrostomy feeding tube was placed to allow nutritional support postoperatively. Medical treatment for oesophagitis was initiated after surgery. No complications were encountered and the cat was discharged 4 days after surgery.

Partial Esophagectomy with Single Layer Closure for Treatment of Esophageal Sarcomas in 6 Dogs

OBJECTIVE

To report partial esophagectomy (PE) as a treatment for esophageal sarcoma in dogs.

STUDY DESIGN

Retrospective study (2000-2002).

ANIMALS

Six dogs with caudal thoracic esophageal tumors.

METHODS

Medical records of 6 dogs that had surgical removal of esophageal tumors were reviewed. Signalment, medical history, physical examination results, complete blood count, surgical procedure, tumor classification, postoperative treatment, and complications were retrieved.

RESULTS

Esophageal masses were approached by thoracotomy and esophagotomy on the side opposite the mass, removed with 1 cm margins by full thickness excision, and the defects closed with a single layer of interrupted sutures. All dogs recovered rapidly without major complications. Tumors were fibrosarcoma (3 dogs), undifferentiated sarcoma (1), and osteosarcoma (2). Five dogs were administered doxorubicin chemotherapy after surgery. Good quality of life was observed postoperatively in 5 dogs until deterioration necessitated euthanasia; survival ranged from 2-16 months. The remaining dog was alive, 20 months after surgery.

CONCLUSIONS

Partial esophagectomy and closure using 1 suture layer, was an effective, simple, and safe technique for removal of sarcomas of the distal thoracic esophagus.

CLINICAL RELEVANCE

Removal of esophageal masses by partial esophagectomy can be used reliably as a method of esophageal surgery.

Fluoroscopic and endoscopic localization of an esophagobronchial fistula in a dog

A 10-month-old, intact male Chihuahua presented for a 7-month history of regurgitation and coughing. Survey radiographs revealed a soft-tissue opacity within the distal esophagus. A contrast study confirmed the presence of an esophagobronchial fistula. Endoscopic removal of foreign material within the esophagus allowed for visualization of an esophageal diverticulum. Bronchoscopic examination revealed the presence of an abnormal opening in a right caudal tertiary bronchus. Passage of a cardiac guidewire was accomplished, confirming the presence of the fistula and aiding its subsequent surgical removal.