The Thorax. Small animal surgery

The veTerinary publishing company

As in previous books, the illustrations play an important role and, combined with a highly instructive text, provide a faithful representation of the surgical procedures. As a result, this is a high-quality book that will be of great help to veterinary clinicians and undergraduates.

This time, the lecturers at the University of Zaragoza and clinicians at the Veterinary Hospital of the Zaragoza Faculty of Veterinary Medicine (HCVZ) combine their experience and expertise with that of other surgical specialists to enhance wherever possible the contents of this book.

Surgery atlas, a step-by-step guide

This latest book in the series ‘Small animal surgery’ concerns the thorax and gives a detailed and clear description of the most common surgical procedures in this region as well as some of the latest techniques.

The thorax

Small animal surgery

small animals

Small animal surgery José Rodríguez Gómez (Editor and coordinator) María José Martínez Sañudo Jaime Graus Morales

Rib cage

The Thorax small animal surgery

Oesophagus

Technical specificaTions

Lungs

authors:José Rodríguez Gómez

Cardiovascular system Cranial mediastinum Trachea General techniques

Surgery atlas, a step-by-step guide

The thorax

(Editor and coordinator) María José Martínez Sañudo Jaime Graus Morales

format: 23 x 29.7 cm number of pages: 380 number of images: 1,000 binding: Hardcover isbn: 978-84-92569-99-1 This new volume of the collection presents the anatomical region of the thorax. It describes the most common surgical procedures, for instance the thoracotomy or the placement of a thoracic drainage; and also the most complex ones like the placement of a transvalvular patch, the extraction of oesophagic foreign bodies, tracheal collapse treatment or innovative techniques such as cardioplasty in idiopatic megaesophagus cases.

The high quality of its images, some of them come with diagrams and illustrations, allow an accurate description of the pathologies and their etiology.

Aimed at veterinary surgeons, students, teachers and other professionals in the veterinary sector.

Centro Empresarial El Trovador, planta 8, oficina I - Plaza Antonio Beltrán Martínez, 1 • 50002 Zaragoza - España Tel.: 976 461 480 • Fax: 976 423 000 • pedidos@grupoasis.com • Grupo Asís Biomedia, S.L.

The veTerinary publishing company

The Thorax. small animal surgery Table of conTenTs 1. introduction 2. rib cage and thoracic cavity Overview Instruments and equipment for thoracic surgery Pleural space

Megaoesophagus. Overview Idiopathic megaoesophagus.

Oesophagus-diaphragmatic cardioplasty Case 1 / Megaoesophagus

4. lungs

Pneumothorax

Overview

Case 1 / Traumatic pneumothorax

Pulmonary neoplasia

Pleural effusion Chylothorax Case 1 / Chylothorax Pyothorax Diaphragm. Overview Diaphragmatic rupture Case 1 / Complicated radial rupture in a dog Case 2 / Circumferential avulsion in a cat Peritoneal-pericardial diaphragmatic hernia Case 1 / PPDH in a dog

Case 1 / Hypertrophic osteopathy (Pierre Marie syndrome) Pulmonary abscess Encapsulated abscess in the caudal mediastinum Lung lobe torsion

5. cardiovascular system Overview Patent ductus arteriosus (PDA).

Overview

Oesophageal hiatus hernia. Overview

PDA. Conventional surgical treatment

Case 1 / Para-oesophageal hiatus hernia and gastro-oesophageal intussusception

Case 1 / Intraoperative rupture of a PDA

Rib cage. Overview Flail chest

3. oesophagus Overview Oesophageal foreign bodies. Overview Case 1 / Foreign body in the caudal thoracic oesophagus. Oesophagotomy Case 2 / Foreign body in the caudal thoracic oesophagus. Gastrotomy Persistence of the right aortic arch (PRAA)

Case 2 / Closure with a surgical stapler Case 3 / PDA. Occlusion using the Amplatzer Canine Duct Occluder (ACDO) Pulmonary valve stenosis. Overview Treatment of pulmonary valve stenosis.

Valvuloplasty Treatment of pulmonic stenosis.

Transvalvular patch (open patch graft) Vascular occlusion entry technique.

Complete occlusion of venous return Cardiac tamponade Cardiac neoplasms. Overview

Case 1 / Persistence of the right aortic arch (PRAA)

Centro Empresarial El Trovador, planta 8, oficina I - Plaza Antonio Beltrán Martínez, 1 • 50002 Zaragoza - España Tel.: 976 461 480 • Fax: 976 423 000 • pedidos@grupoasis.com • Grupo Asís Biomedia, S.L.

The veTerinary publishing company

6. cranial mediastinum

8. general techniques

Overview

Anaesthesia for thoracic surgery

Feline thymoma

Thoracic drains

Tumour in the cranial mediastinum

7. Trachea Trachea. Overview Tracheal collapse Tracheal collapse. Extraluminal cervical tracheoplasty Tracheal collapse. Intraluminal tracheoplasty

Thoracocentesis Fixation of tubes and drains Thoracic radiography Thoracic cytology Thoracic endoscopy Minimally invasive surgery Interventional radiology Thoracoscopy. Overview Thoracotomy. Overview Lateral thoracotomy Midline thoracotomy

Centro Empresarial El Trovador, planta 8, oficina I - Plaza Antonio Beltrán Martínez, 1 • 50002 Zaragoza - España Tel.: 976 461 480 • Fax: 976 423 000 • pedidos@grupoasis.com • Grupo Asís Biomedia, S.L.

Thorax of the dog

Rib cage and thoracic cavity

Diaphragm Thoracic view Intercostal spaces

Left

Descending aorta

Right Longissimus m. of the thorax Diaphragm (left crus)

Oesophagus Pulmonary veins Diaphragm

Instruments and equipment for thoracic surgery

Pleural space

Vagal trunks

Aorta Oesophagus

Heart

Overview

Caudal vena cava

Diaphragm (costal part)

Central tendon of the diaphragm

Diaphragm (sternal part) Transverse m. of the thorax

Sternum

Pneumothorax Case 1 / Traumatic pneumothorax Pleural effusion Chylothorax Case 1 / Chylothorax Pyothorax

Left pulmonary a.

Left subclavian a.

Cranial vena cava

Pulmonary trunk Brachiocephalic trunk

6

7

Transverse section. Caudal view Left

Longitudinal section. Dorsal view

Right

Left

Right Pleural dome

Right lung Left lung Oesophagus

Pleural space Costal pleura Descending aorta Dorsal vagal trunk

Oesophagus

Diaphragm. Overview

Abdominal view Left Transversus abdominis m.

Abdominal retractor m.

Aortic hiatus

Diaphragmatic rupture Right

Case 1 / Complicated radial rupture in a dog

Psoas minor m.

Diaphragm (lumbar part), left and right crura

Pulmonary pleura Ventral vagal trunk Phrenic nerve

Oesophageal

hiatus

Endothoracic fascia Central tendon of the diaphragm

Pericardial pleura Heart

Pericardial cavity Parietal pericardium

Caval foramen Diaphragm (costal part) Diaphragm (sternal part)

Visceral pericardium Mediastinal pleura Diaphragmatic pleura

Peritoneal-pericardial diaphragmatic hernia Case 1 / PPDH in a dog Oesophageal hiatus hernia. Overview Case 1 / Para-oesophageal hiatus hernia and gastro-oesophageal intussusception

Left lung Caudal vena cava

Case 2 / Circumferential avulsion in a cat

Xiphoid process

Rib cage. Overview Flail chest

Thorax of the dog

Rib cage and thoracic cavity

Diaphragm Thoracic view Intercostal spaces

Left

Descending aorta

Right Longissimus m. of the thorax Diaphragm (left crus)

Oesophagus Pulmonary veins Diaphragm

Instruments and equipment for thoracic surgery

Pleural space

Vagal trunks

Aorta Oesophagus

Heart

Overview

Caudal vena cava

Diaphragm (costal part)

Central tendon of the diaphragm

Diaphragm (sternal part) Transverse m. of the thorax

Sternum

Pneumothorax Case 1 / Traumatic pneumothorax Pleural effusion Chylothorax Case 1 / Chylothorax Pyothorax

Left pulmonary a.

Left subclavian a.

Cranial vena cava

Pulmonary trunk Brachiocephalic trunk

6

7

Transverse section. Caudal view Left

Longitudinal section. Dorsal view

Right

Left

Right Pleural dome

Right lung Left lung Oesophagus

Pleural space Costal pleura Descending aorta Dorsal vagal trunk

Oesophagus

Diaphragm. Overview

Abdominal view Left Transversus abdominis m.

Abdominal retractor m.

Aortic hiatus

Diaphragmatic rupture Right

Case 1 / Complicated radial rupture in a dog

Psoas minor m.

Diaphragm (lumbar part), left and right crura

Pulmonary pleura Ventral vagal trunk Phrenic nerve

Oesophageal

hiatus

Endothoracic fascia Central tendon of the diaphragm

Pericardial pleura Heart

Pericardial cavity Parietal pericardium

Caval foramen Diaphragm (costal part) Diaphragm (sternal part)

Visceral pericardium Mediastinal pleura Diaphragmatic pleura

Peritoneal-pericardial diaphragmatic hernia Case 1 / PPDH in a dog Oesophageal hiatus hernia. Overview Case 1 / Para-oesophageal hiatus hernia and gastro-oesophageal intussusception

Left lung Caudal vena cava

Case 2 / Circumferential avulsion in a cat

Xiphoid process

Rib cage. Overview Flail chest

The thorax

Rib cage and thoracic cavity / Overview Instruments and equipment for thoracic surgery

General complications that may occur during thoracic surgery

Instruments

When planning and performing a surgical procedure of the thorax, the following possible complications should be borne in mind.

■■ Increase

Haemothorax

■■ Altered

The presence of blood in the pleural space may be a serious complication in thoracic surgery, and any kind of bleeding should be controlled, whether it originates from the thoracic wall (muscular layers, intercostal vessels or sternebrae) or the systemic circulation (bronchial arteries, mediastinal vessels, azygos system).

Dogs are able to absorb 30% of their blood volume from the pleural space within 90 hours, provided that the bleeding is under control.

Any significant haemothorax should be drained to prevent respiratory distress by pleural effusion. Hypovolaemia should be controlled through fluid therapy and blood transfusion if necessary.

This type of complication will normally appear within 24 hours. If it occurs later, it is most probably due to vascular erosion and an emergency thoracotomy should be performed.

12

Pneumothorax

page 265

Pulmonary oedema Pulmonary oedema is the abnormal accumulation of fluid in the interstitial space, airways and alveoli, changing the balance between the fluid transport through the capillaries and lymphatic drainage of the lungs. This fluid accumulation interferes with the gas exchange in the lungs, leading to respiratory distress.

There are many possible causes of pulmonary oedema. The most common are: ■■ Increased

in the negative pressure in the interstitial space, due to a rapid aspiration of a pneumothorax, in an erroneous attempt to speed recovery of the patient.

Apart from the general instruments needed for any surgical procedure, thoracic surgery requires specific instruments:

permeability of the alveolar capillary membrane due to aspiration of material from the digestive tract.

Treatment of this complication is based on the administration of oxygen, corticosteroids, diuretics and bronchodilators.

Atelectasis

Instruments for thoracic surgery should be long (average 18-24 cm) so that they can reach into the deepest part of the operating field, which is also quite narrow.

A collapsed lung can be caused by compression of the lung or by airway obstruction.

Atelectasis commonly occurs during thoracic surgery, and after surgery there is always a certain degree of lung compression.

In certain cases, the lung volume is reduced during anaesthesia as the dry incoming air impairs the surfactant. Furthermore, postoperative pain reduces respiratory movements and coughing, leading to an accumulation of secretions and causing the small airways to collapse, which reduces the lung volume and pulmonary compliance.

To prevent atelectasis, air or fluid should be removed from the thorax to improve pulmonary expansion. Postoperative analgesia enhances the depth of respiration and coughing. It can also be beneficial to change the position of the patient and perform thoracic percussion to mobilise secretions.

■■ Finochietto

rib retractors of various sizes according to the pa-

tient (fig. 1).

■■ Self-retaining

retractors used in traumatology: these may be used instead of the Finochietto retractors in small dogs and cats (fig. 2).

Fig. 1. The Finochietto rib retractors are very powerful and keep the ribs or the sternum separated after thoracotomy. The surgeon should at least have a large and a medium size available.

13

Acute respiratory failure

Postoperative residual pneumothorax is a normal occurrence, and the pleura is able to absorb the air rapidly. However, its progress should be monitored with daily radiographs.

A pneumothorax due to a badly placed or maintained chest drain may constitute a serious complication, because air will enter the thoracic cavity through or around the drain.

See thoracic drainage.

José Rodríguez, Amaya de Torre

pulmonary capillary pressure, secondary to left-sided heart failure or iatrogenic over-hydration due to excessive fluid administration.

Acute respiratory failure occurs if the patient is unable to maintain pulmonary gas exchange.

This complication is due to hypercapnia (PaCO2 > 45 mmHg) and hypoxaemia (PaO2 < 60 mmHg) as a result of a ventilation-perfusion mismatch in the patient.

Treatment includes oxygen therapy, corticosteroids, antibiotics, diuretics and bronchodilators as well as positive pressure ventilation at the end of expiration.

Cardiac arrhythmias

A

B

Heart surgery may cause cardiac abnormalities following manipulation of the myocardium, but may also occur in the course of any surgical intervention of the thoracic cavity.

Causes of this complication include the following: ■■ Increased

pulmonary vascular resistance.

■■ Mediastinal ■■ Increased

masses.

vagal tone.

■■ Hypoxaemia.

■■ Electrolyte

and acid-base disturbances.

■■ Underlying

heart disease or disorder.

Fig. 2. In puppies, cats and small dogs, the ribs can be spread with retractors used in traumatology, such as the Gelpi (A) or Schuhknecht retractors (B).

The thorax

Rib cage and thoracic cavity / Overview Instruments and equipment for thoracic surgery

General complications that may occur during thoracic surgery

Instruments

When planning and performing a surgical procedure of the thorax, the following possible complications should be borne in mind.

■■ Increase

Haemothorax

■■ Altered

The presence of blood in the pleural space may be a serious complication in thoracic surgery, and any kind of bleeding should be controlled, whether it originates from the thoracic wall (muscular layers, intercostal vessels or sternebrae) or the systemic circulation (bronchial arteries, mediastinal vessels, azygos system).

Dogs are able to absorb 30% of their blood volume from the pleural space within 90 hours, provided that the bleeding is under control.

Any significant haemothorax should be drained to prevent respiratory distress by pleural effusion. Hypovolaemia should be controlled through fluid therapy and blood transfusion if necessary.

This type of complication will normally appear within 24 hours. If it occurs later, it is most probably due to vascular erosion and an emergency thoracotomy should be performed.

12

Pneumothorax

page 265

Pulmonary oedema Pulmonary oedema is the abnormal accumulation of fluid in the interstitial space, airways and alveoli, changing the balance between the fluid transport through the capillaries and lymphatic drainage of the lungs. This fluid accumulation interferes with the gas exchange in the lungs, leading to respiratory distress.

There are many possible causes of pulmonary oedema. The most common are: ■■ Increased

in the negative pressure in the interstitial space, due to a rapid aspiration of a pneumothorax, in an erroneous attempt to speed recovery of the patient.

Apart from the general instruments needed for any surgical procedure, thoracic surgery requires specific instruments:

permeability of the alveolar capillary membrane due to aspiration of material from the digestive tract.

Treatment of this complication is based on the administration of oxygen, corticosteroids, diuretics and bronchodilators.

Atelectasis

Instruments for thoracic surgery should be long (average 18-24 cm) so that they can reach into the deepest part of the operating field, which is also quite narrow.

A collapsed lung can be caused by compression of the lung or by airway obstruction.

Atelectasis commonly occurs during thoracic surgery, and after surgery there is always a certain degree of lung compression.

In certain cases, the lung volume is reduced during anaesthesia as the dry incoming air impairs the surfactant. Furthermore, postoperative pain reduces respiratory movements and coughing, leading to an accumulation of secretions and causing the small airways to collapse, which reduces the lung volume and pulmonary compliance.

To prevent atelectasis, air or fluid should be removed from the thorax to improve pulmonary expansion. Postoperative analgesia enhances the depth of respiration and coughing. It can also be beneficial to change the position of the patient and perform thoracic percussion to mobilise secretions.

■■ Finochietto

rib retractors of various sizes according to the pa-

tient (fig. 1).

■■ Self-retaining

retractors used in traumatology: these may be used instead of the Finochietto retractors in small dogs and cats (fig. 2).

Fig. 1. The Finochietto rib retractors are very powerful and keep the ribs or the sternum separated after thoracotomy. The surgeon should at least have a large and a medium size available.

13

Acute respiratory failure

Postoperative residual pneumothorax is a normal occurrence, and the pleura is able to absorb the air rapidly. However, its progress should be monitored with daily radiographs.

A pneumothorax due to a badly placed or maintained chest drain may constitute a serious complication, because air will enter the thoracic cavity through or around the drain.

See thoracic drainage.

José Rodríguez, Amaya de Torre

pulmonary capillary pressure, secondary to left-sided heart failure or iatrogenic over-hydration due to excessive fluid administration.

Acute respiratory failure occurs if the patient is unable to maintain pulmonary gas exchange.

This complication is due to hypercapnia (PaCO2 > 45 mmHg) and hypoxaemia (PaO2 < 60 mmHg) as a result of a ventilation-perfusion mismatch in the patient.

Treatment includes oxygen therapy, corticosteroids, antibiotics, diuretics and bronchodilators as well as positive pressure ventilation at the end of expiration.

Cardiac arrhythmias

A

B

Heart surgery may cause cardiac abnormalities following manipulation of the myocardium, but may also occur in the course of any surgical intervention of the thoracic cavity.

Causes of this complication include the following: ■■ Increased

pulmonary vascular resistance.

■■ Mediastinal ■■ Increased

masses.

vagal tone.

■■ Hypoxaemia.

■■ Electrolyte

and acid-base disturbances.

■■ Underlying

heart disease or disorder.

Fig. 2. In puppies, cats and small dogs, the ribs can be spread with retractors used in traumatology, such as the Gelpi (A) or Schuhknecht retractors (B).

The thorax

Rib cage and thoracic cavity / Pleural space

Pleural space Fig. 11. To open the stapler, release the lever A so

C

B

that the cartridge B is separated from the anvil C. Next, the tissue to be stapled is placed between B and C.

A

Pleural changes

A. Lever to move the head containing the staples.

The pleura is a serous membrane that covers all surfaces of the thoracic cavity:

B. Staple cartridge. Its colour depends on the size of the staples it contains.

■■ The

Changes in hydrostatic or oncotic pressure or of lymphatic reabsorption may increase the production of pleural fluid or decrease its absorption, leading to pleural effusion.

Trauma and certain diseases that affect the pleural space may lead to separation of the pleurae, compromising respiration due to the accumulation of air (pneumothorax), fluid (pleural effusion) or both (fig. 1).

There are three kinds of pleural effusion: transudate, modified transudate and exudate (table I).

C. Anvil on which the staples are closed when firing.

D

Prevalence

Overview

The different parts of the surgical stapler are:

E

José Rodríguez, Roberto Bussadori, Amaya de Torre, Silvia María Repetto

parietal pleura covers the thoracic wall, the diaphragm and the structures of the mediastinum.

■■ The

visceral pleura covers the lungs.

D. Security lock to prevent accidental firing of staples.

E. Trigger handle, firing the staples into the tissue placed in the stapler.

In dogs and cats, the mediastinum is perforated so that there is a communication between the two hemithoraces.

Table I. The pleural space lies between these two membranes. This is a virtual space with a negative pressure (4-6 mmHg) allowing lung expansion when the thoracic wall is distended.

To assist the sliding of the pleurae and the movement of the lungs without friction, avoiding injury to the mesothelial cells lining the pleurae, a fluid is secreted by the systemic capillaries of the parietal pleura and absorbed by the pulmonary capillaries of the visceral pleural and by the lymph vessels in the parietal pleura.

Types of pleural effusion Type

Protein (g/L)

Cells (109/L)

Transudate

< 25

< 1-1,5

Modified transudate

> 25

< 5-7

Exudate

> 30

>7

18

19

Pleuritis may impair reabsorption of the pleural fluid, leading to effusion.

The pleural space can also be occupied by abdominal organs passing into the thoracic cavity through defects in the diaphragm (fig. 2).

Fig. 12. To place the stapler around the tissue, squeeze lever A. This will release a metal retaining pin at the far end of the stapler, which will slide into the anvil to ensure

that the staples can be placed correctly. The pin ensures that the tissue does not slip out of the stapling line when the stapler is fired. Then, security lock D is released and the trigger is pulled as far as it goes. After firing the staples, D is returned to the locked position and lever A is released to remove the stapler.

Suture material Suture material used in most intrathoracic surgical procedures should be mounted on atraumatic, round-bodied needles so that it passes through the tissues by separating the fibres (fig. 13). If needles with sharp edges are used, this may cut the tissue and make it more friable, increasing the risk of suture dehiscence.

The thickness of the suture material depends on the tissue concerned. For example, a 5/0 or 6/0 size thread may be used when suturing a vessel, while size 2 may be used when closing a thoracotomy in a large patient.

For more details, see the chapter on surgical techniques.

page 256

Fig. 13. The needles should normally be round-bodied to prevent damaging the

blood vessels of the tissues they pass through.

Fig. 1. Pleural effusion. This radiograph was taken with the animal in standing position, with a horizontal X-ray beam to allow an accurate assessment of the accumulation of fluid in the pleural space, which will gravitate towards the lower part of the thorax.

Fig. 2. Cranial displacement of part of the small intestine and liver due to a traumatic defect of the diaphragm. The lack of detail of the radiograph is due to the presence of a thoracic effusion secondary to the displaced abdominal organs.

The thorax

Rib cage and thoracic cavity / Pleural space

Pleural space Fig. 11. To open the stapler, release the lever A so

C

B

that the cartridge B is separated from the anvil C. Next, the tissue to be stapled is placed between B and C.

A

Pleural changes

A. Lever to move the head containing the staples.

The pleura is a serous membrane that covers all surfaces of the thoracic cavity:

B. Staple cartridge. Its colour depends on the size of the staples it contains.

■■ The

Changes in hydrostatic or oncotic pressure or of lymphatic reabsorption may increase the production of pleural fluid or decrease its absorption, leading to pleural effusion.

Trauma and certain diseases that affect the pleural space may lead to separation of the pleurae, compromising respiration due to the accumulation of air (pneumothorax), fluid (pleural effusion) or both (fig. 1).

There are three kinds of pleural effusion: transudate, modified transudate and exudate (table I).

C. Anvil on which the staples are closed when firing.

D

Prevalence

Overview

The different parts of the surgical stapler are:

E

José Rodríguez, Roberto Bussadori, Amaya de Torre, Silvia María Repetto

parietal pleura covers the thoracic wall, the diaphragm and the structures of the mediastinum.

■■ The

visceral pleura covers the lungs.

D. Security lock to prevent accidental firing of staples.

E. Trigger handle, firing the staples into the tissue placed in the stapler.

In dogs and cats, the mediastinum is perforated so that there is a communication between the two hemithoraces.

Table I. The pleural space lies between these two membranes. This is a virtual space with a negative pressure (4-6 mmHg) allowing lung expansion when the thoracic wall is distended.

To assist the sliding of the pleurae and the movement of the lungs without friction, avoiding injury to the mesothelial cells lining the pleurae, a fluid is secreted by the systemic capillaries of the parietal pleura and absorbed by the pulmonary capillaries of the visceral pleural and by the lymph vessels in the parietal pleura.

Types of pleural effusion Type

Protein (g/L)

Cells (109/L)

Transudate

< 25

< 1-1,5

Modified transudate

> 25

< 5-7

Exudate

> 30

>7

18

19

Pleuritis may impair reabsorption of the pleural fluid, leading to effusion.

The pleural space can also be occupied by abdominal organs passing into the thoracic cavity through defects in the diaphragm (fig. 2).

Fig. 12. To place the stapler around the tissue, squeeze lever A. This will release a metal retaining pin at the far end of the stapler, which will slide into the anvil to ensure

that the staples can be placed correctly. The pin ensures that the tissue does not slip out of the stapling line when the stapler is fired. Then, security lock D is released and the trigger is pulled as far as it goes. After firing the staples, D is returned to the locked position and lever A is released to remove the stapler.

Suture material Suture material used in most intrathoracic surgical procedures should be mounted on atraumatic, round-bodied needles so that it passes through the tissues by separating the fibres (fig. 13). If needles with sharp edges are used, this may cut the tissue and make it more friable, increasing the risk of suture dehiscence.

The thickness of the suture material depends on the tissue concerned. For example, a 5/0 or 6/0 size thread may be used when suturing a vessel, while size 2 may be used when closing a thoracotomy in a large patient.

For more details, see the chapter on surgical techniques.

page 256

Fig. 13. The needles should normally be round-bodied to prevent damaging the

blood vessels of the tissues they pass through.

Fig. 1. Pleural effusion. This radiograph was taken with the animal in standing position, with a horizontal X-ray beam to allow an accurate assessment of the accumulation of fluid in the pleural space, which will gravitate towards the lower part of the thorax.

Fig. 2. Cranial displacement of part of the small intestine and liver due to a traumatic defect of the diaphragm. The lack of detail of the radiograph is due to the presence of a thoracic effusion secondary to the displaced abdominal organs.

The thorax

Rib cage and thoracic cavity / Diaphragm

Next, the bowel loops were gently extracted from the thoracic cavity and repositioned in the abdomen (fig. 6).

Fig. 6. Traction on the intestinal loops should be gentle to avoid damage to the wall or the mesentery.

Fig. 9. The adhesions should be handled with care to

avoid liver lesions and bleeding.

After returning the bowel loops to the abdomen, several liver lobes were found in the thoracic cavity (fig. 7). These had to be returned to their normal position with care, so as not to damage them.

52

The abnormal position of the liver leads to congestion due to inadequate systemic venous return. Affected liver lobes become increased in size and friable.

If too many days have passed between the diaphragmatic rupture and the surgical intervention, liver adhesions should be expected in the thoracic cavity.

53

Fig. 7. The caudate lobe that was still located in the abdomen had increased in size due to stasis of the blood.

Fig. 10. This image shows cutting the adhesions

between the right lateral lobe and the thoracic wall.

After sectioning hepatic adhesions, the liver lobes were returned to their anatomical position. The caudate lobe was returned to the abdominal cavity without major problems, but the hepatomegaly in the right lobes impeded their passage through the diaphragmatic rupture (fig. 11).

To minimize the risk of a revascularisation syndrome, methylprednisolone (30 mg/kg) was injected IV.

Each of the hepatic lobes was mobilised with care to detect adhesions in the thoracic cavity and avoid rupture of the parenchyma (fig.

8). The fibrous adhesions were cut with scissors until the affected liver lobes were completely free (figs. 8-10).

Handling of the liver lobes is made easier when they are grasped with swabs moistened in sterile saline.

Fig. 8. The caudate liver lobe had significant adhesions to the diaphragmatic cupola (arrow).

Fig. 11. Secondary hepatomegaly due to liver congestion makes it impossible to

reposition the right lateral lobe in the abdominal cavity.

The thorax

Rib cage and thoracic cavity / Diaphragm

Next, the bowel loops were gently extracted from the thoracic cavity and repositioned in the abdomen (fig. 6).

Fig. 6. Traction on the intestinal loops should be gentle to avoid damage to the wall or the mesentery.

Fig. 9. The adhesions should be handled with care to

avoid liver lesions and bleeding.

After returning the bowel loops to the abdomen, several liver lobes were found in the thoracic cavity (fig. 7). These had to be returned to their normal position with care, so as not to damage them.

52

The abnormal position of the liver leads to congestion due to inadequate systemic venous return. Affected liver lobes become increased in size and friable.

If too many days have passed between the diaphragmatic rupture and the surgical intervention, liver adhesions should be expected in the thoracic cavity.

53

Fig. 7. The caudate lobe that was still located in the abdomen had increased in size due to stasis of the blood.

Fig. 10. This image shows cutting the adhesions

between the right lateral lobe and the thoracic wall.

After sectioning hepatic adhesions, the liver lobes were returned to their anatomical position. The caudate lobe was returned to the abdominal cavity without major problems, but the hepatomegaly in the right lobes impeded their passage through the diaphragmatic rupture (fig. 11).

To minimize the risk of a revascularisation syndrome, methylprednisolone (30 mg/kg) was injected IV.

Each of the hepatic lobes was mobilised with care to detect adhesions in the thoracic cavity and avoid rupture of the parenchyma (fig.

8). The fibrous adhesions were cut with scissors until the affected liver lobes were completely free (figs. 8-10).

Handling of the liver lobes is made easier when they are grasped with swabs moistened in sterile saline.

Fig. 8. The caudate liver lobe had significant adhesions to the diaphragmatic cupola (arrow).

Fig. 11. Secondary hepatomegaly due to liver congestion makes it impossible to

reposition the right lateral lobe in the abdominal cavity.

The thorax

A 6 to 12 mm stomach tube is introduced to facilitate the visualisation and manipulation of the abdominal oesophagus and stomach (fig. 11).

Rib cage and thoracic cavity / Diaphragm

Great care should be taken at this stage so as not to damage the vessels that supply the oesophagus or the vagal trunks.

By pulling on the stomach, some 2 to 3 centimetres of the thoracic oesophagus enter the abdominal cavity. This increases the external pressure on the distal oesophagus and the risk of gastro-oesophageal reflux is reduced.

The stomach is pulled caudally, the oesophagus is placed in its dorsal position next to the vertebral column and the hiatus is plicated and reduced.

Fig. 11. Placement of a large-bore stomach tube

helps to identify and manipulate the oesophagus. In this French Bulldog, a 10 mm tube was used.

Reduction of the hiatal plication Caudal traction is applied to the stomach to visualise and dissect the phreno-oesophageal ligament. To assist in the manipulation of the stomach and prevent vascular and nervous injury in the area, a vascular tape or Penrose drain is placed around the abdominal oesophagus (fig. 12).

Special care should be taken not to damage the dorsal and ventral vagal trunks that run along the oesophagus.

To reduce the size of the hiatus, several sutures are placed. Horizontal mattress sutures are made using a monofilament synthetic absorbable material mounted on an atraumatic cylindrical needle.

Great care should be taken not to damage the phrenic vessels, vena cava or vagal trunks (fig. 14).

The new diameter of the hiatus should be approximately 10 mm in cats and small dogs, and 10-15 mm in medium and large dogs.

The hiatus should be reduced around a stomach tube to avoid constriction.

74

75 Fig. 14. Closure and plication of the ventral side Fig. 12. To prevent vascular and nervous injury

to the stomach and assist in its manipulation, a Penrose drain is placed around the abdominal oesophagus.

This image shows the start of the dissection and section of the phreno-oesophageal ligament.

Next, the ligament that attaches the oesophagus to the diaphragm is cut over 180Âş of its ventral side (which is close to the surgeon); at this moment, the thoracic cavity is opened, so that the anaesthetist should be ready to maintain the patientâ&#x20AC;&#x2122;s respiration (figs. 12 and 13).

of the oesophageal hiatus (green arrow) with two horizontal mattress sutures in a 3/0 monofilament absorbable material (blue arrow).

Special care should be taken not to damage the vagal nerves that run along the oesophagus (yellow arrow) or the vena cava, that may be close (white arrow).

Oesophagopexy Oesophagopexy consists of placing several simple interrupted sutures around the oesophagus to attach it to the hiatus. These sutures include all layers of the oesophagus except the mucosa (figs. 15 and 16).

Fig. 13. Section of the phreno-oesophageal ligament

in the ventral area of the hiatus in order to return the oesophagus to its correct position and reduce the oesophageal hiatus to its normal size. Note the large size of the hiatus in this patient.

Fig. 15. The oesophagus is attached to its hiatus

using several simple sutures in the same material as used before. The sutures should not perforate the mucosa, to avoid infection complications.

The thorax

A 6 to 12 mm stomach tube is introduced to facilitate the visualisation and manipulation of the abdominal oesophagus and stomach (fig. 11).

Rib cage and thoracic cavity / Diaphragm

Great care should be taken at this stage so as not to damage the vessels that supply the oesophagus or the vagal trunks.

By pulling on the stomach, some 2 to 3 centimetres of the thoracic oesophagus enter the abdominal cavity. This increases the external pressure on the distal oesophagus and the risk of gastro-oesophageal reflux is reduced.

The stomach is pulled caudally, the oesophagus is placed in its dorsal position next to the vertebral column and the hiatus is plicated and reduced.

Fig. 11. Placement of a large-bore stomach tube

helps to identify and manipulate the oesophagus. In this French Bulldog, a 10 mm tube was used.

Reduction of the hiatal plication Caudal traction is applied to the stomach to visualise and dissect the phreno-oesophageal ligament. To assist in the manipulation of the stomach and prevent vascular and nervous injury in the area, a vascular tape or Penrose drain is placed around the abdominal oesophagus (fig. 12).

Special care should be taken not to damage the dorsal and ventral vagal trunks that run along the oesophagus.

To reduce the size of the hiatus, several sutures are placed. Horizontal mattress sutures are made using a monofilament synthetic absorbable material mounted on an atraumatic cylindrical needle.

Great care should be taken not to damage the phrenic vessels, vena cava or vagal trunks (fig. 14).

The new diameter of the hiatus should be approximately 10 mm in cats and small dogs, and 10-15 mm in medium and large dogs.

The hiatus should be reduced around a stomach tube to avoid constriction.

74

75 Fig. 14. Closure and plication of the ventral side Fig. 12. To prevent vascular and nervous injury

to the stomach and assist in its manipulation, a Penrose drain is placed around the abdominal oesophagus.

This image shows the start of the dissection and section of the phreno-oesophageal ligament.

Next, the ligament that attaches the oesophagus to the diaphragm is cut over 180Âş of its ventral side (which is close to the surgeon); at this moment, the thoracic cavity is opened, so that the anaesthetist should be ready to maintain the patientâ&#x20AC;&#x2122;s respiration (figs. 12 and 13).

of the oesophageal hiatus (green arrow) with two horizontal mattress sutures in a 3/0 monofilament absorbable material (blue arrow).

Special care should be taken not to damage the vagal nerves that run along the oesophagus (yellow arrow) or the vena cava, that may be close (white arrow).

Oesophagopexy Oesophagopexy consists of placing several simple interrupted sutures around the oesophagus to attach it to the hiatus. These sutures include all layers of the oesophagus except the mucosa (figs. 15 and 16).

Fig. 13. Section of the phreno-oesophageal ligament

in the ventral area of the hiatus in order to return the oesophagus to its correct position and reduce the oesophageal hiatus to its normal size. Note the large size of the hiatus in this patient.

Fig. 15. The oesophagus is attached to its hiatus

using several simple sutures in the same material as used before. The sutures should not perforate the mucosa, to avoid infection complications.

The thorax

Rib cage and thoracic cavity / Diaphragm

The next step was section of the ligament that joins the ventral oesophagus to diaphragm (fig. 7).

Considering the lesions in the oesophageal mucosa, it was decided to place a feeding tube in the stomach to avoid the transit of food and water through the oesophagus (fig. 11).

Additionally, a chest drain was placed to check for the development of a pleural effusion and simplify recovery from the pneumothorax (fig. 12).

Fig. 7. To reposition the oesophagus in its correct anatomical position, the phreno-oesophageal ligament should be cut.

After returning the oesophagus to its anatomical position on the dorsal side of the hiatus (fig. 8), the hiatus was reduced, as described (figs. 9 and 10).

80

A pneumothorax is created by cutting the phreno-oesophageal ligament; from this moment onwards, assisted ventilation is required.

81

Fig. 8. Before suturing the area, a stomach tube

should be placed to delineate the oesophagus, to avoid excessive closure of the hiatus.

Fig. 11. The gastropexy was combined with the placement of a feeding tube in

Fig. 12. Final image after the operation that shows the chest drain and the feeding

the stomach. The image shows how part of the omentum is placed around the gastrotomy to promote the adhesion of the stomach to the abdominal wall and avoid leaking of the stomach contents into the abdominal cavity.

tube in the stomach.

After surgery During the immediate postoperative period, the pleural contents were aspired every two hours. Twelve hours after the operation (fig. 13), no air could be extracted and the chest drain was removed the next day.

Antibiotic treatment was maintained for five days and the metoclopramide and omeprazole for two weeks.

A liquid nutritional recovery diet was administered through the stomach tube for six days. On the seventh day, the dog started to take oral food.

From the fourth day onwards, the owners continued the treatment at home. Recovery was normal. On the ninth day after the operation, the sutures were removed and four days later, the stomach tube.

Fig. 9. The sutures should create a strong bond between the oesophagus and the diaphragm, so each suture should include sufficient tissue of both structures.

Fig. 10. The oesophageal sutures should never perforate the mucosa; they should

only include the tunica adventitia and submucosa. This image shows the end result of the hiatal reduction and the oesophagopexy.

Fig. 13. The thorax was drained every two hours. Twelve hours after the operation,

the pneumothorax had disappeared. The next day, the drain yielded nothing, so it was removed.

The thorax

Rib cage and thoracic cavity / Diaphragm

The next step was section of the ligament that joins the ventral oesophagus to diaphragm (fig. 7).

Considering the lesions in the oesophageal mucosa, it was decided to place a feeding tube in the stomach to avoid the transit of food and water through the oesophagus (fig. 11).

Additionally, a chest drain was placed to check for the development of a pleural effusion and simplify recovery from the pneumothorax (fig. 12).

Fig. 7. To reposition the oesophagus in its correct anatomical position, the phreno-oesophageal ligament should be cut.

After returning the oesophagus to its anatomical position on the dorsal side of the hiatus (fig. 8), the hiatus was reduced, as described (figs. 9 and 10).

80

A pneumothorax is created by cutting the phreno-oesophageal ligament; from this moment onwards, assisted ventilation is required.

81

Fig. 8. Before suturing the area, a stomach tube

should be placed to delineate the oesophagus, to avoid excessive closure of the hiatus.

Fig. 11. The gastropexy was combined with the placement of a feeding tube in

Fig. 12. Final image after the operation that shows the chest drain and the feeding

the stomach. The image shows how part of the omentum is placed around the gastrotomy to promote the adhesion of the stomach to the abdominal wall and avoid leaking of the stomach contents into the abdominal cavity.

tube in the stomach.

After surgery During the immediate postoperative period, the pleural contents were aspired every two hours. Twelve hours after the operation (fig. 13), no air could be extracted and the chest drain was removed the next day.

Antibiotic treatment was maintained for five days and the metoclopramide and omeprazole for two weeks.

A liquid nutritional recovery diet was administered through the stomach tube for six days. On the seventh day, the dog started to take oral food.

From the fourth day onwards, the owners continued the treatment at home. Recovery was normal. On the ninth day after the operation, the sutures were removed and four days later, the stomach tube.

Fig. 9. The sutures should create a strong bond between the oesophagus and the diaphragm, so each suture should include sufficient tissue of both structures.

Fig. 10. The oesophageal sutures should never perforate the mucosa; they should

only include the tunica adventitia and submucosa. This image shows the end result of the hiatal reduction and the oesophagopexy.

Fig. 13. The thorax was drained every two hours. Twelve hours after the operation,

the pneumothorax had disappeared. The next day, the drain yielded nothing, so it was removed.