Endoscopy, biopsy and endosurgery

image of Endoscopy, biopsy and endosurgery
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Compared with other invasive techniques, endoscopy is relatively simple and easy to perform. Endoscopy is also valuable for diagnosing conditions affecting a flock, and offers an alternative to sacrificial necropsy. This chapter covers equipment, patient preparation and contraindications, evaluation of internal organs and complications of a range of endoscopic and endosurgical procedures.

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12.1 Types of endoscope. Top to bottom: 1.9 mm diameter scope, 2.7 mm diameter scope and 4 mm diameter scope. The different viewing angles available (0 degrees and 30 degrees) are shown in the top left-hand corner of the figure.
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12.2 (a) View through a4 mm, 0-degree endoscope, which allows only a straight forward view. (b) View through a 2.7 mm, 30-degree endoscope. The 30-degree angle allows a panoramic view by turning the scope around its optical axes.
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12.3 A flexible 22 G needle in a plastic sleeve can be used for the endoscopic administration of medication and the collection of aspirate biopsy samples.
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12.4 Excessive fat deposits are commonly seen in poultry and can obscure the view of other internal organs.
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12.5 (a) The opening of the trachea is located at the base of the tongue. (b) The tracheal rings in birds are closed and the mucosa appears slightly red.
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12.6 For gastroscopy and cloacoscopy, a working channel is required for water insufflation to allow examination of the hollow organs. 1 = inlet (left) and outlet (right) water taps; 2 = working channel for endoscopic instruments. The arrows indicate the direction of water flow.
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12.7 (a) When entering the oesophagus, the mucosal folds are clearly visible. Insufflation with air or water increases the pressure within the oesophagus, causing it to expand. (b) The mucosal fold (arrowed) can be used to locate the entrance to the crop.
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12.8 Endoscopic view upon entering the cloaca. Papillae are clearly visible when water is used for insufflation.
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12.9 Patient positioning for laparoscopy. (a) The chicken has been placed in lateral recumbency with the wing pulled dorsally and the legs pulled caudally. The arrow indicates the incision site. (b) The incision site (3) is located using a triangle drawn from behind the last rib (1) to the cranial border of the iliotibialis muscle (2).
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12.10 The iliotibialis muscle is pushed caudally using curved forceps to allow visualization of the body wall. (The skin has been removed for better demonstration.)
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12.11 Depending on the orientation of the forceps or trocar when penetrating the body wall, either (a) the caudal thoracic air sac or (b) the abdominal air sac will be entered.
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12.12 Correct handling technique for the endoscope: the hand of the clinician should be in contact with the bird at all times.
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12.13 (a) Gross anatomy of the bird from a left lateral view. a (yellow circle) = entrance for the endoscope; 1 = lung; 2 = heart; 3 = liver; 4 = intestine; 5 = kidney; 6 = spleen; 7 = proventriculus. (b) Gross anatomy of the body cavity. The arrow demonstrates the direction of the endoscope for full exploration of the body cavity. 1 = lung; 2 = heart; 3 = liver; 4 = intestine; 5 = kidney; 6 = gonads and adrenal gland; 7 = spleen; 8 = proventriculus; 9 = ventriculus.
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12.14 (a) Endoscopic view upon entering the abdominal air sac. 1 = kidney; 2 = ovary; 3 = intestine; 4 = adrenal gland; 5= uterus/ureter. (b) Endoscopic view upon entering the abdominal air sac with the scope positioned at a slightly more downwards angle than in (a). 1 = spleen; 2 = adrenal gland; 3 = kidney; 4 = intestine; 5 = proventriculus. (c) Endoscopic view upon entering the caudal thoracic air sac. 1 = liver; 2 = proventriculus; 3 = lung; 4 = retrograde entrance into the lung; 5 = hole in the air sac (made by surgeon to access the abdominal air sac).
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12.15 The connection between the caudal thoracic air sac and lung allows a retrograde internal exploration of the lung and evaluation of the honeycomb structure. This type of view is not possible via tracheobronchoscopy.
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12.16 The suspensory ligament of the ovary is important in determining sex in poultry. 1 = suspensory ligament; 2 = ovary; 3 = adrenal gland; 4 = kidney.
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12.17 The gonads can be difficult to assess in juvenile birds. The lack of a suspensory ligament in this case indicates a male bird. 1 = kidney; 2 = testicle; 3 = adrenal gland.
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12.19 Reddening of the tracheal mucosa is a clear sign of irritation or inflammation. The presence of blood in the trachea, as in this case, indicates severe disease such as infectious laryngotracheitis. The clinician should also be aware that iatrogenic damage to the trachea (mucosal irritation and haemorrhage) can occur with inappropriate handling of the endoscope.
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12.20 Endoscopic view of the thyroid glands and trachea after bypassing the heart. 1 = thyroid glands; 2 = trachea.
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12.21 (a) The air sac of a healthy bird is like a window. The internal organs behind the air sac can be seen and only a few vessels are present. (b) Granuloma detached from the wall within the caudal thoracic air sac.
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12.22 The presence of foreign material is a clear sign of infection and can be easily sampled for cytology and microbiology during endoscopy. In chickens, this foreign material can also be egg yolk, resulting in aseptic egg yolk peritonitis.
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12.23 The proventriculus (1) is a compact organ above the liver and below the lung (2).
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12.24 Endoscopic view of the deferent duct of a sexually active cock. The festoon appearance makes identification easy.
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12.25 The pancreas is visible within the duodenal loop.
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12.26 Endoscopic view of the liver. Note the homogeneous brown-red colour and sharp border.
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12.27 Colour change in the liver is always a pathological alteration. In this case, haemosiderosis is present. Note that haemorrhage may have a similar appearance.
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12.28 Multiple white foci within the liver typically represent (a) areas of necrosis or (b) granulomas/tubercles. Granulomas and tubercles are usually visible above the surface of the liver, whereas areas of necrosis appear below the surface. Differential diagnoses include , , tuberculosis, herpesvirus and histomoniasis.
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12.29 A swollen spleen is regularly seen with systemic infections. Colour changes or areas of necrosis (as seen in this case) are occasionally visible. Splenic biopsy may be of value if the infectious agent cannot be detected by other means. Differential diagnoses include herpesvirus or adenovirus.
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12.30 Large granuloma during laser ablation.
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12.31 Double-entry technique for minimally invasive surgery in birds. The insertions points for the endoscope (2) and additional working channel for instruments (1) are shown.
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12.32 Triple-entry technique for minimally invasive surgery in birds. (a) The insertion points for the endoscope (1) and two additional working channels for instruments (2) are shown. (b) Correct placement of the endoscope and cannulas for triple-entry techniques in a chicken. (c) Correct triangulation of the endoscope (middle) and instruments is vital for successful surgery.
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12.33 A diode laser can be used to vaporize the ovary in juvenile birds.
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12.34 Sterilization of an adult male bird. The deferent duct is elevated and cut using a pair of scissors. This procedure must be performed in two locations in order to remove at least 1 cm of the duct to prevent reunion.
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12.35 Cranial pole of the kidney of a male bird 3 months following castration using a diode laser. Note the absence of testicular tissue.
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