Respiratory

Question 1

Cranial nerve whose branches innervate the intrinsic muscles of the canine larynx. Also name of the branch

Answer 1

Vagus nerve (10th pair), recurrent laryngeal nerve branches

Question 2

Muscles that contribute to the abduction of the arytenoid cartilages

Answer 2

Intrinsic laryngeal abductor and cricoarytenoideus dorsalis

Question 3

Breeds affected by congenital laryngeal paralysis

Answer 3

Bouvier de Flandres, bull terriers, Siberian huskies and white coated German Shepherd

Question 4

Proposed etiologies of laryngeal paralysis (7)

Answer 4

Congenital (Bouvier the Flanders Road, bullterriers, Siberian huskies, white coated German shepherds)

Accidental trauma (Penetrating wounds)

Surgical trauma (cranial thoracic surgery, thyroidectomy, parathyroidectomy, tracheal surgery, ventral slot)

Cervical or intrathoracic
neoplasia (Lymphoma, thyroid carcinoma)

Neuromuscular disease (Geriatric onset, hypothyroidism, hypoadrenocorticism)

Immune mediated (Myasthenia gravis, polymyopathy, infectious)

Systemic lupus erythematosus

Question 5

Describe the basic goal of the most common method of surgical treatment of laryngeal paralysis

Answer 5

The most common technique involves suturing the cricoid cartilage to the muscular process of the arytenoid cartilage. This mimics the directional pull of the cricoarytenoid dorsalis muscle and rotates the arytenoid cartilage laterally.

Question 6

Describe the Arytenoid lateralization technique

Answer 6

Make a skin incision just ventral to the jugular vein, beginning at the caudal angle of the mandible and extending over the dorsolateral aspect of the larynx to 1 to 2 cm caudal to the larynx (Fig. 28.28A). Incise and retract the SC tissues, platysma, and parotidoauricularis muscles. Retract the sternocephalicus muscle and the jugular vein dorsally and the sternohyoid muscle ventrally to expose the laryngeal area. Palpate the dorsal margin of the thyroid cartilage. Incise the thyropharyngeus muscle along the dorsolateral margin of the thyroid cartilage laminate Place a stay suture through the thyroid cartilage lamina to retract and rotate the larynx laterally. Identify and transect the cricoarytenoideus dorsalis muscle. Disarticulate the cricothyroid articulation with a No. 11 blade or scissors (Fig. 28.28B); however, this step is often unnecessary. Palpate, identify, and disarticulate the cricoarytenoid articulation at the muscular process. Place a nonabsorbable monofilament suture (e.g., 2-0 to 0 polypropylene [Prolene], polybutester [Novafil]) from the caudal one-third of the cricoid cartilage near the dorsal midline to the muscular process of the arytenoid cartilage to mimic the direction of the cricoarytenoid dorsalis muscle Tie the suture with enough tension to abduct the arytenoid cartilage moderately. Have an assistant verify abduction by intraoral visualization of the larynx. If abduction is insufficient, the suture can be repositioned to achieve better abduction. Lavage the surgical site. Appose the thyropharyngeus muscle in a cruciate or simple continuous pattern with 3-0 absorbable suture. Appose the SC tissues and skin routinely.

Question 7

Factors associated with an increased risk of aspiration ammonia following arytenoid cartilage lateralization

Answer 7

Increasing age, temporary tracheostomy, progressive neurologic disease, postoperative megaesophagus, ongoing esophageal disease, concomitant neoplasia and postoperative administration of opioids

Question 8

Name the 12 axial pattern flaps available in dogs.

Answer 8

1) Superficial temporal
2) Caudal Auricular (sternocleidomastoideus branches of the caudal auricular artery)
3) Omocervical
4) Thoracodorsal
5) Lateral thoracic
6) Superficial brachial
7) Cranial superficial epigastric
8) Caudal superficial epigastric
9) Deep Circumflex Iliac
10) Genicular
11) Reverse Saphenous conduit
12) Lateral caudal

Question 9

What is the use of the superficial temporal axial Pattern flap?

Answer 9

Ipsilateral and contralateral head and face, particularly maxillofacial defects

Question 10

Which axial pattern flap can be passed through a parapharyngeal tunnel to cover oronasal defects caudal to the third premolar?

Answer 10

Omocervical Axial Pattern Flap

Question 11

Axial pattern flap utilized to cover defects of the antebrachium

Answer 11

Superficial brachial Axial Pattern flap

Question 12

Of the 12 Axial pattern flaps available for dogs, how many Have been evaluated in cats? What are their names?

Answer 12

6
Superficial temporal, Caudal auricular, superficial cervical, thoracodorsal, caudal superficial epigastric, reverse saphenous conduit flap

Question 13

Describe the grading system utilized for Tracheal Collapse

Answer 13

Grade 1 -Normal tracheal anatomy; Redundant dorsal tracheal membrane occludes lumen by 25%
Grade 2 – Mild to moderate flattening of tracheal cartilages; 50 % loss of luminal diameter
Grade 3 – Severe flattening of tracheal cartilages; 75% loss of luminal diameter
Grade 4 – Complete obstruction; tracheal lumen is obliterated

Question 14

The overall complication rate for extratracheal Vs endotracheal surgical options for treatment of tracheal collapse

Answer 14

The overall complication rate for extratracheal Vs endotracheal methods is similar, around 42% to 43%

Question 15

Complications associated with endotracheal stent placement for treatment of tracheal collapse

Answer 15

Endotracheal prosthesis may be incorrectly placed or sized, leading to death. Too small implants may migrate, while too large implants may lead to tracheal necrosis. Stents too close to the larynx may lead to intractable laryngospasm. Granulomas may develop in 20 to 30% of cases and require management with steroids. Persistent cough, pneumothorax, emphysema, infection, mucous obstruction, tracheal rupture, ulceration of the tracheal epithelium, implant fracture, implant collapse or deformation.

Question 16

Complications associated with the placement of extra tracheal rings for treatment of tracheal collapse.

Answer 16

Extratracheal prosthetic ring application may lead to damage to tracheal vasculature and innervation (Recurrent laryngeal nerves) during application, leading to tracheal necrosis and laryngeal paresis/paralysis respectively. Infection deriving from penetration of the tracheal lumen; Improperly aerated EO sterilized prosthesis (syringe case rings) can lead to extensive tissue reaction; These complications may be lethal.

Question 17

Spinal segment origin of the phrenic nerves

Answer 17

C5,6 and 7

Question 18

Respiratory infections are often caused by gram negative bacteria. What antibiotics are typically used to treat these infections?

Answer 18

“Antibiotics commonly recommended for treatment of upper respiratory disease include ampicillin, fluoroquinolones, cephalosporins, doxycycline, azithromycin, and potentiated sulfonamides (see Box 28.4).”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 19

What bacteria are most commonly isolated from the respiratory tract of normal dogs?

Answer 19

“Streptococci, Escherichia coli, Pseudomonas spp., Klebsiella spp., and Bordetella bronchiseptica are the bacteria most commonly isolated from normal dogs.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 20

How much of the trachea can be resected and still directly anastomosed?

Answer 20

“Depending on the degree of tracheal elasticity and tension, approximately 20% to 50% of the trachea in an adult dog (approximately 8–10 rings) may be resected and direct anastomosis achieved”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 21

When is ventriculocordectomy considered acceptable according. To AVMA? What’s the preferred approach?

Answer 21

“The policy of the American Veterinary Medical Association regarding canine devocalization is that it should only be performed by qualified, licensed veterinarians as a final alternative to euthanasia after behavioral modification to correct excessive vocalization has failed and after discussion of potential complications from the procedure with the owner. Ventriculocordectomy may be performed through an oral or ventral (laryngotomy) approach. The ventral approach is recommended.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 22

Discuss the healing mechanism of the trachea

Answer 22

“Tracheal epithelium responds immediately to irritation or disease by increased production of mucus. If the insult continues, cells desquamate and goblet cell hyperplasia occurs to increase the protective mucous layer. Superficial wounds heal by reepithelialization. Healing begins within 2 hours after sloughing of superficial cells. Intact ciliated columnar cells surrounding the defect flatten, lose their cilia, and migrate over the wound. Mitosis begins approximately 48 hours after injury in the ciliated columnar and basal epithelial cells. Organization and differentiation begin after 4 days. Squamous cells replace ciliated and goblet cells if injury recurs without healing. Full-thickness tracheal mucosal wounds with a gap between mucosal edges fill with granulation tissue before reepithelialization. Full-thickness wounds may heal with scar tissue protruding into the lumen. Scar tissue narrows the lumen and may interfere with transport of mucus. A 20% reduction in lumen diameter may reduce mucociliary clearance by more than 50%.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 23

Five most common errors in managing patients with upper respiratory disease

Answer 23

“• Failing to diagnose and treat upper respiratory disease before secondary problems develop (i.e., aspiration pneumonia)
• Failing to recognize laryngeal collapse
• Causing trauma to the recurrent laryngeal nerves
• Rough handling or overhandling of tissue, causing excessive swelling
• Failing to monitor the patient intensively after surgery”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 24

What brachycephalic breed is most likely to have a poor outcome from upper airway surgery?

Answer 24

“English bulldogs are more likely to have a negative outcome compared with other breeds.11”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 25

Describe the function and innervation of the palatine muscle

Answer 25

“The palatine muscle, which is covered by mucosa and innervated by the pharyngeal plexus (cranial nerves IX and X), shortens the soft palate during contraction. ”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 26

What are the three stages of laryngeal collapse?

Answer 26

“Laryngeal collapse is described in three stages: stage 1 is commonly referred to as laryngeal saccule eversion (see p. 851); stage 2 collapse is medial deviation of the cuneiform cartilage and aryepiglottic fold, or aryepiglottic collapse; stage 3 collapse is medial deviation of the corniculate process of the arytenoid cartilages, or corniculate collapse. Stages 2 and 3 are advanced stages of laryngeal collapse.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 27

What two conditions are considered predisposing factors for laryngeal collapse?

Answer 27

“Animals with brachycephalic syndrome (see p. 849) or laryngeal paralysis (see p. 858) are predisposed to laryngeal collapse. ”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 28

You operate on a English bulldog to address brachycephalic upper airway syndrome. The patient does very well initially, but a few days later the clinical signs of relapse with moderate to severe respiratory distress. What is the most likely differential diagnosis?

Answer 28

Laryngeal collapse

Question 29

What are the 3 described stages of laryngeal collapse?

Answer 29

“Stage 1 laryngeal collapse (lateral saccule eversion) is recognized as prolapsed, edematous mucosa just rostral to the vocal cords at the ventral aspect of the glottis (see p. 851).

Stage 2 laryngeal collapse is present when one or both aryepiglottic folds are deviated medially and obstruct the ventral aspect of the glottis (Fig. 28.27).

Stage 3 laryngeal collapse occurs when the corniculate processes of the arytenoid cartilages deviate medially from their normal paramedian position and are not adequately abducted during inspiration. The cartilages often have a flaccid appearance.”

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Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 30

List 4 breeds predisposed to congenital, inherited laryngeal paralysis

Answer 30

“Congenital, inherited laryngeal paralysis occurs in Bouviers des Flandres, bull terriers, Siberian huskies, and white-coated German shepherd dogs. ”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 31

What is the proposed pathoanatomy, potential causes and currently proposed new designation for acquired laryngeal paralysis?

Answer 31

“Acquired laryngeal paralysis is caused by damage to the recurrent laryngeal nerve or intrinsic laryngeal muscles most often attributed to polyneuropathy, polymyopathy, accidental or iatrogenic trauma, or intrathoracic or extrathoracic masses, although many other causes have been proposed (Box 28.9). It has been shown that many dogs thought to have idiopathic acquired laryngeal paralysis develop systemic neurologic signs within 1 year following diagnosis of laryngeal paralysis, which is consistent with progressive generalized neuropathy.15 Abnormalities in the results of electrodiagnostic tests and histopathologic analysis of nerve and muscle biopsy specimens reflecting generalized polyneuropathy have been documented in a small number of dogs with acquired laryngeal paralysis.16 Therefore it has been proposed that dogs previously believed to have idiopathic laryngeal paralysis may in fact have a progressive generalized polyneuropathy.17,18 The abbreviation GOLPP (geriatric onset laryngeal paralysis polyneuropathy) has been proposed as a more accurate term for dogs with acquired laryngeal paralysis where other causes have been ruled out.1”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 32

Briefly describe the typical presentation, pathoanatomy and proposed causes of laryngeal paralysis in the cat

Answer 32

“Laryngeal paralysis is an uncommon condition in the cat. Clinical presentation is similar to that of the dog; however, cats with unilateral laryngeal paralysis can present with significant clinical signs, unlike dogs, which are rarely symptomatic. A prevalence of left-sided unilateral laryngeal paralysis has been noted in cats, similar to what is reported in humans and horses. The specific cause of laryngeal paralysis in cats is unknown, but several cases have been associated with trauma, neoplastic invasion, and iatrogenic damage.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 33

What radiographic pattern do you expect to observe in a patient with post obstruction pulmonary edema, such as caused by laryngeal paralysis?

Answer 33

“Postobstruction pulmonary edema may occur in dogs and can be recognized as an interstitial pattern (sometimes coalescing to an alveolar pattern) on thoracic films. ”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 34

What endocrinopathy is frequently involved in the pathophysiology of laryngeal paralysis in dogs? What percentage of dogs with acquired laryngeal paralysis also have this endocrine disease?
Will treatment of this condition improve laryngeal collapse?

Answer 34

“Hypothyroid neuropathy (see p. 615) should be excluded by evaluation of serum total thyroxine (T4) and endogenous canine thyroid-stimulating hormone concentrations; approximately 30% to 40% of dogs with acquired laryngeal paralysis have concurrent hypothyroidism.”

“Hypothyroidism should be appropriately treated; however, no improvement in clinical signs related to laryngeal paralysis should be expected.”

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Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 35

What is the reported rate of aspiration pneumonia after arytenoid lateralization surgery? What factors may influence the occurrence of this complication?

Answer 35

“Aspiration pneumonia occurs in approximately 10% to 20% of dogs after surgery for laryngeal paralysis. It may occur any time after surgery. Factors associated with a high risk of developing aspiration pneumonia include increasing age, temporary tracheostomy, progressive neurologic disease, postoperative megaesophagus, esophageal disease, concurrent neoplastic disease, and postoperative administration of opioids.”

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Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 36

Proposed etiology of epiglottis retroversion and most-commonly affected breed

Answer 36

“theories about etiology in dogs include hypothyroid-associated peripheral neuropathy, epiglottic fracture or malacia, and denervation of the hypoglossal nerve or the glossopharyngeal nerve or both. Evaluation of this condition found that almost 80% of dogs diagnosed with epiglottic retroversion had concurrent or historical upper airway disorders.18 Therefore epiglottic retroversion may most likely occur secondary to chronic increased inspiratory airway pressures that can occur with other causes of upper airway obstruction.”

Yorkshire Terrier

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Question 37

Typical clinical history of dogs with epiglottic retroversion

Answer 37

“Dogs present with acute or chronic signs of upper airway obstruction: respiratory distress caused by inspiratory stridor. Signs may be intermittent, with dogs being clinically normal between episodes. Respiratory distress may be precipitated by stress or exercise. In some dogs, clinical signs may be worse when the animal is sleeping.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 38

What other conditions should you also rule out when performing laryngoscopy to evaluate a case of suspected epiglottic retroversion?

Answer 38

“Dogs should also be evaluated for laryngeal paralysis, laryngeal collapse, elongated soft palate, tracheal collapse, and bronchial collapse.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 39

For the treatment of epiglottic retroflexion: preferred technique

Answer 39

“For subtotal epiglottectomy, use Metzenbaum scissors, a radiofrequency surgical unit, or a carbon dioxide laser to transect the epiglottis at the widest part, approximately 0.5 to 1 cm from the tip of the epiglottis. Close incised mucosal edges using 3-0 to 4-0 rapidly absorbable suture in a simple continuous pattern to cover the exposed cartilage.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 40

What are Oncocytomas? What’s the typical signalment and prognosis for affected dogs?

Answer 40

“Oncocytomas arise from epithelial cells called oncocytes, small numbers of which are found in various organs, such as the larynx, thyroid, pituitary, and trachea.”

“Rhabdomyomas and oncocytomas are laryngeal tumors that appear histologically similar with light microscopy; electron microscopy and immunocytochemistry are necessary to distinguish them. Oncocytomas have been reported in young dogs and warrant special consideration because long-term survival of patients without metastasis has been reported after surgical resection (Fig. 28.29).”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 41

What are the three types of inflammatory laryngeal disease in dogs? What’s the potential consequence of this disorder?

Answer 41

“Inflammatory laryngeal disease is an uncommon nonneoplastic condition of the arytenoid cartilages of the larynx that has been reported in both dogs and cats. It can be granulomatous, lymphocytic-plasmacytic, or eosinophilic in nature, with multiple factors likely contributing to development of the disease. Severe cases can result in laryngeal stenosis and significant upper airway obstruction. ”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 42

Parasitic tracheal and mainstem bronchi of dogs, causing neoplastic-like nodules.

Answer 42

“Oslerus osleri (Filaroides osleri) is a nematode that forms neoplastic-appearing nodules in the canine trachea and mainstem bronchi (Fig. 28.30). Nonendoscopic diagnosis of filaroidosis (i.e., finding larvae by Baermann fecal examination) is difficult because larvae are intermittently shed in the feces. Diagnosis is best made by finding larvae or adults by tracheal cytology. Anthelmintic therapy and surgical resection have met with varying success. ”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 43

Behavior and typical signalment of tracheal osteochondromas

Answer 43

“Tracheal osteochondromas may occur in dogs younger than 1 year of age. These masses probably reflect a malfunction of osteogenesis and are benign. Their growth is expected to stop with skeletal maturity. ”

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Question 44

Recommended biopsy technique for tracheal or laryngeal masses

Answer 44

“It is usually advisable to first attempt brush cytology because this is faster and less risky. If cytology is not diagnostic, then one may take a biopsy of the mass; however, one should inspect the mass first and note the blood supply. If numerous vessels are seen on the mass, then hemorrhage is a greater risk, and suction (usually through the endoscope) must be readily available.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 45

Medical management options for laryngeal/tracheal tumors

Answer 45

“Radiation therapy may help treat squamous cell carcinomas, mast cell tumors, and lymphomas, but little information is available. Some tumors (e.g., lymphomas, mast cell tumors, adenocarcinomas) often respond to chemotherapy. Permanent tracheostomy (see p. 843) can palliate signs of respiratory distress during medical therapy.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 46

Discuss the surgical removal of tracheal tumors. How much of the trachea can be successfully removed still allowing primary anastomosis?

Answer 46

“For removal of tracheal tumors, tracheal resection and end-to-end anastomosis are required (see p. 844). Depending on its elasticity, 20% to 50% of the trachea (i.e., usually eight to ten rings) may be resected. Resection of large tumors with a minimum of 1 cm of normal trachea on both sides of the mass is not always possible. When resection would be too extensive to achieve, end-to-end anastomosis, tracheal replacement, or prostheses may be considered but are rarely successful. Resection of a segment of the tracheal wall without complete transection (i.e., wedge resection) with reapposition of the cut edges is not recommended because it narrows, or kinks, the trachea, which interferes with airflow and mucociliary transport.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 47

Discuss the post-op management of patients who underwent laryngotomy or tracheotomy for tumor resection

Answer 47

“Postoperatively, these patients should be monitored carefully for signs of airway obstruction. Supplemental oxygen and glucocorticoids may be given if needed. Water should be offered 6 to 12 hours postoperatively and food 18 to 24 hours after surgery if gagging, regurgitation, or vomiting does not occur. The animal should be kept quiet without exercise for 2 to 4 weeks. Endoscopic reevaluation is recommended at 4 to 8 weeks to identify tumor recurrence or stenosis. Stenosis of greater than 20% leads to mucostasis and infection, whereas a decrease in lumen size of approximately 50% causes respiratory distress. Periodic physical and radiographic evaluation is recommended to check for metastasis or recurrence.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 48

What are the most common complications post-tracheotomy or tracheal anastomosis? How can they be minimized?

Answer 48

“Dehiscence may occur after tracheal anastomosis if tension is excessive and if head and neck motion are not restricted. To relieve tension, the neck should be kept mildly to moderately ventroflexed by attaching a muzzle to a harness with a lead or by placing a suture from the chin to the manubrium for 2 weeks. SC emphysema may be evident with dehiscence or anastomotic leakage. Infection and fistula formation are possible. Mild stenosis (<20%) is expected with the split-cartilage technique, in which anastomotic tension is minimal.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 49

The cause of tracheal collapse is not entirely understood. What re some of the proposed causes? What happens to the tracheal cartilage rings in cases of tracheal collapse?

Answer 49

“The cause of tracheal collapse is unknown and probably multifactorial. Proposed causes include genetic factors, nutritional factors, allergens, neurologic deficiency, small airway disease, and degeneration of cartilage matrices. Affected tracheal cartilages become hypocellular, and their matrices degenerate. Normal hyaline cartilage is replaced by fibrocartilage and collagen fibers, and the quantities of glycoprotein and glycosaminoglycans are diminished. The cartilages lose their rigidity and their ability to maintain normal tracheal conformation during the respiratory cycle.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 50

Where is tracheal collapse most commonly observed? Why?

Answer 50

“The thoracic inlet is most susceptible to tracheal collapse because this is the site of the equal pressure point: where intrapleural pressure equals intraluminal airway pressure, and where the transition from intrapleural to atmospheric pressure occurs (Fig. 28.33).”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 51

What are some of the concurrent conditions typically occurring concomitantly with tracheal collapse?

Answer 51

Almost 50% of dogs suffer from a degree of obesity that will worsen clinical signs.

Laryngeal paresis or paralysis - 20% to 30% of dogs

One-third of dogs have concurrent systolic heart murmur consistent with mitral valve insufficiency.

Upper respiratory signs may be aggravated by an enlarged left atrium putting pressure on the carina and mainstem bronchi.

40% of dogs are thought to have a degree of dental or periodontal disease. Aspiration of oral bacteria into diseased airways is hypothesized to contribute to exacerbation of clinical signs caused by increased airway inflammation or increased coughing.

Concurrent hepatomegaly and hepatopathy are common in dogs with tracheal collapse. The reason for this association is unclear, although speculative theories include passive hepatic congestion and centrilobular liver cell necrosis secondary to chronic hypoxia.”

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Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
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Question 52

Diagnostic accuracy of inspiratory/expiratory radiographs for severe tracheal collapse (Grade 2 or higher)

Answer 52

“Inspiratory and expiratory lateral radiographs of the neck and thorax are diagnostic in approximately 60% of patients with severe tracheal collapse (>50% of the lumen)”

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Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 53

Location of the left and right recurrent laryngeal nerves as it applies to tracheal surgery

Answer 53

“The segmental blood and nerve supply to the trachea travels in the lateral pedicles on each side of the trachea. Minimal mobilization of the trachea is necessary to maintain a good blood supply after surgery. The left recurrent laryngeal nerve is located in the lateral pedicle; the right is sometimes located within the carotid sheath.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 54

Describe the technique for making and placement of extraluminal tracheal stents.

Answer 54

“Incise the skin and SC tissues along the ventral cervical midline from the larynx to the manubrium. Separate the sternohyoid and sternocephalicus muscles along their midline to expose the cervical trachea. Examine the trachea for evidence of collapse and deformity (Fig. 28.35). Identify and protect the recurrent laryngeal nerves. Place the first tracheal prosthesis one or two cartilages distal to the larynx. Dissect the peritracheal tissues and create a tunnel immediately around the trachea only in the areas of prosthetic ring placement. Guide and position a prosthetic ring through the tunnel and around the trachea with a long, curved hemostat (Fig. 28.36A–B). Position the prosthetic ring with the split on the ventral aspect of the trachea. Chondrotomy is occasionally necessary to allow deformed, rigid cartilages to conform to the prosthesis. Secure the prosthesis with sutures ventrally, laterally, and dorsally (Fig. 28.36.C). Place three to six sutures (3-0 or 4-0 polypropylene [Prolene], polybutester [Novafil], or polydioxanone [PDS]) to secure each prosthesis. Direct sutures around rather than through cartilages, and engage the trachealis muscle in at least one suture. Place four to six additional ring prostheses 5 to 8 mm apart along the trachea (Fig. 28.37). Cranial traction[…]”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 55

Reported incidence of major complications for extra and intraluminal tracheal stents

Answer 55

“Regardless, the most recent report on the incidence of major complications between extraluminal and endoluminal stenting found them to be similar (42%–43%).26”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 56

Mean survival time for dogs receiving extraluminal or intraluminal tracheal stents can be long, often exceeding 1500 days. What single factor is most often associated with shorter survival?

Answer 56

“Regardless of treatment type, the presence of mainstem bronchi collapse is associated with shorter survival times.26”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 57

Name three bacteria that compose the normal nasal flora of dogs and cats

Answer 57

“E. coli, Streptococcus spp., Pasteurella spp.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 58

Most common nasal fungi to affect dogs (2) and cats (1)

Answer 58

“aspergillosis and penicilliosis in dogs; cryptococcosis in cats”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 59

What is the prognosis for dogs with nasal tumors treated with surgery alone? What is the recommended adjuvant modality for nasal carcinomas?

Answer 59

“Radiotherapy appears to be the most effective treatment for nasal carcinomas.”

“Surgery as the sole treatment for dogs with nasal tumors has not prolonged survival time. The poor response of dogs with nasal tumors to surgery is due to the advanced nature of most tumors at the time of diagnosis, a propensity for these tumors to invade bones that are inaccessible or that cannot be surgically removed, and lack of appreciable encapsulation; each of these makes it almost impossible to completely remove the tumor. However, surgery may palliate clinical signs in some dogs by alleviating obstruction and epistaxis. Surgery may be of value in patients with recurrence following radiation therapy.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 60

Median survival time for dogs with sinonasal tumors treated treated with stereotactic radiation therapy

Answer 60

“The use of cone-based stereotactic radiosurgery for canine sinonasal tumors appears promising, as it is currently associated with an overall median survival time of 8.5 months.28”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 61

What precaution regarding instrument length must always be observed when performing nasal biopsies?

Answer 61

“Transnostril core biopsies may be obtained by using the outer protective shield of a Sovereign catheter with the end cut off at a sharp angle, or an alligator forceps. To prevent inadvertent penetration of the cribriform plate, the catheter or forceps should be measured with the tip placed at the medial canthus of the eye; these instruments should not be advanced past this point. ”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 62

Prognosis (MST) for dogs and cats with nasal tumors;

Adenocarcinoma Vs carcinoma Vs sarcoma

Answer 62

“The prognosis for dogs with nasal tumors is generally poor. In patients not treated and in those treated with surgery, chemotherapy, immunotherapy, or cryosurgery, the mean survival time is generally 3 to 6 months. Improvement in this survival period has been accomplished with radiation therapy combined with or without surgical debulking (see previous discussion), with mean reported survival times of 8 to 25 months. Animals with lymph node or pulmonary metastasis have shortened median survival times. The prognosis for carcinoma is better than that for sarcoma, and adenocarcinoma appears to have the best overall prognosis. It is unlikely that therapy will result in cure in most dogs, and more successful local control may lead to increased detection of metastasis. Conversely, the prognosis for cats with lymphoid neoplasia of the nasal cavity appears good.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 63

What essential precaution must be taken prior to topical clotrimazole therapy for nasal aspergillosis?

Answer 63

“Complications and death may occur if the cribriform plate is not intact; therefore a CT scan should be done before clotrimazole therapy is administered.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 64

Nasal clotrimazole infusions are very effective at treating the nasal form of aspergillosis. What are the two most serious complications associated which this type of treatment?

Answer 64

“Seizures and sometimes death occur if the cribriform plate has been eroded. Pneumonia may occur if clotrimazole is aspirated.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 65

When is Reexpansion Pulmonary Edema (RPE) likely to occur? (conditions, timing). What is the pathophysiology of the condition?

Answer 65

“It is possible for RPE to occur in any type of chronically collapsed lung that can be reexpanded. Therefore lung protective ventilator strategies are recommended for any lung reexpansion surgeries (e.g., diaphragmatic hernia, pectus excavatum, pleural effusion, pneumothorax, large pulmonary neoplasia). RPE is characterized by fluid within the alveoli, interstitial edema, and thickened basement membranes. It is believed that RPE is a permeability pulmonary edema associated with the injury of pulmonary microvessels.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 66

What are the two proposed causes of Reexpansion Pulmonary Injury?

Answer 66

“There are two major causes of RPE. One is the abnormality of the pulmonary microvessels caused by the chronic collapse. The microvasculature becomes thickened, less flexible, and more susceptible to injury. The second is mechanical stress caused by the abrupt reexpansion.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 67

Discuss strategies to avoid Reexpansion Pulmonary Injury (RPE)

Answer 67

“To avoid RPE, there are two general concepts to consider. The first is slow recruitment of collapsed lung by using PEEP. A PEEP of 5 to 10 helps to prevent recollapsing of alveoli and the associated atelectrauma. The second strategy is to be very careful not to over distend healthy lungs. This may be challenging because most veterinary anesthesia machines do not have measured tidal volume displays. Therefore careful observation of the lungs within the surgical field is imperative. Use estimated tidal volumes of less than 6 mL/kg, being careful not to over inflate normal lung tissue. Do not attempt to rapidly recruit collapsed lung because this will only damage healthy, compliant lung. To achieve adequate oxygenation, lung volumes will need to be small and respiratory rates more frequent. Do not administer “sighs,” as they will almost certainly cause overdistention. Once the chest tube is in place and the thoracic closure is being completed, do not distend the lungs to remove the air from the pleural space. Slowly correct the pneumothorax by incrementally removing small portions over several hours. The goal is to gradually reduce the pneumothorax to avoid further lung trauma, rather than rapid correction. Although not easy[…]”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 68

What’s the appropriate use of intraoperative antibiotics during pulmonary surgery?

Answer 68

“Appropriate use of prophylactic antibiotics depends on the length of surgery, the type of surgery being performed, the animal’s immune status, and the underlying disease process. Debilitated animals undergoing thoracotomy for removal of large neoplastic lesions (which may contain focal areas of necrosis) are likely to benefit from prophylactic antibiotic therapy. Prophylactic antibiotics should be given intravenously at induction of anesthesia and generally discontinued immediately after surgery or within 12 to 24 hours (see Chapter 9).”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 69

What muscles are responsible for inspiration and for expiration? Include the function of intercostal and accessory respiratory muscles

Answer 69

Inspiratory muscles:
External intercostals
Scalenes
Serratus dorsalis cranialis
Levator costalis
Diaphragm

Expiratory muscles:
Internal Intercostals
Rectus abdominis
External abdominal oblique
Internal abdominal oblique
Transversus abdominis
Serratus dorsalis caudalis
Transversus costarus
Iliocostalis

“The deepest muscles of the thoracic wall are the intercostal muscles. The fibers of the external intercostal muscle arise on the caudal border of each rib and run caudoventrally to the cranial border of the next rib. This muscle is important primarily in inspiration. The internal intercostal muscles, on the other hand, run from the cranial border of one rib to the caudal border of the preceding rib, primarily functioning to aid expiration. Other inspiratory muscles are the scalenus, serratus dorsalis cranialis, levatores costarum, and diaphragm. Additional expiratory muscles include the rectus abdominis, external abdominal oblique, internal abdominal oblique, transversus abdominis, serratus dorsalis caudalis, transversus costarum, and iliocostalis.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 70

Describe the three stages of Laryngeal Collapse?

Answer 70

Stage 1: Everted Laryngeal Saccules
Stage 2: Medial displacement of the cuneiform processes of the aryepiglottic folds
Stage 3: Collapse of the corniculate processes of the arytenoid cartilages

Question 71

How much of the lungs can be safely removed in the dog?

Answer 71

50%

Transient respiratory acidosis and exercise intolerance may occur.

Question 72

What are the main complications associated with thoracotomies? Overall rate? How can they be avoided?

Answer 72

Overall complication rate 40%, mostly wound and thoracic drain issues.

Air leakage and hemorrhage. Minor air leaks resolve spontaneously, but severe leakage or hemorrhage require emergency revision surgery.

Sternotomy delayed healing/nonunion. Avoided by keeping several sternebrae intact and adequately closing with cerclage.

Pyothorax 6.5%, with 67% mortality

SQ seroma on ventral aspect of thoracotomy. Avoided by careful closure of the Serratus Ventralis and Pectoral muscles.

Postoperative lameness/pain due to latissimus dorsi myotomy. Self-resolving but avoidable if lat is not transected.

Question 73

When are antibiotics indicated in cases of thoracic trauma?

Answer 73

Pulmonary contusions or hemorrhage

Question 74

What’s the emergency care for flail chest?

Answer 74

Place patient with affected side down to minimize fractures segment movement and lung damage. Stabilize patient with analgesia, O2, IVF, etc…
Surgical repair or external splinting.

Question 75

Most common primary lung tumor in dogs; most common location and biological behavior.

Answer 75

Adenocarcinoma, followed by a aplastic carcinoma and SCC
Right caudal lung lobe
Highly aggressive. About 50% of adenocarcinomas and nearly all AC and SCC metastatic at the time of diagnosis. Metastasis typically to the lung itself.

Question 76

Name 5 tumors likely to cause metastatic pulmonary neoplasia

Answer 76

Mammary carcinoma
Thyroid carcinoma
Hemangiosarcoma
Osteosarcoma
Transitional Cell Carcinoma

Question 77

List the 3 bacteria most commonly cultured from pulmonary abscesses

Answer 77

PEK

Pseudomonas spp

E. coli

Klebsiella spp

Question 78

Parasitic agent that causes lung lesions which may resemble neoplasia or abscess, but is treated medically.

Answer 78

Paragonimus kellicotti (lung flukes)
Infection through consumption of raw crayfish or crabs. Flukes migrate from GI tract through diaphragm to lungs.

Question 79

Proposed pathophysiology of lung lobe torsion. Most commonly affected lobe.

Answer 79

Any disease that alters the spacial relationship between the lungs and the thoracic wall/adjacent structures (I.e. lung collapse due to trauma, neoplasia, etc..).

Right middle lobe in large dogs

Left cranial lobe in small dogs

Question 80

Most common causes of lung lobe torsion (6)

Answer 80

Pneumonia
Trauma
Pneumothorax 
Pleural effusion 
Surgical manipulation 
Spontaneous

Question 81

Typical signalment for dogs with lung lobe torsion

Answer 81

Large breed, deep-chested. Afghan Hound predisposed.

LLT also often occurs in small/toy-breed dogs. Young male Pugs predisposed.

Question 82

Most common radiographic finding associated with Lung Lobe Torsion

Answer 82

Pleural effusion

Question 83

When should a thoracostomy tube be removed?

Answer 83

When no air or less than 2.2ml/kg/day of fluid is obtained

Question 84

What syndrome is frequently associated with pectus excavatum?

Answer 84

Swimmer’s syndrome

Question 85

Typical signalment and possible consequences of Pectus Excavatum

Answer 85

Young dog or cat, often brachycephalic. Most commonly asymptomatic but occasionally associated with cardiovascular or respiratory abnormalities.

Question 86

Preferred diagnostic for thoracic trauma and for the diagnosis of pulmonary thromboembolism

Answer 86

Contrast CT

Question 87

Describe the technique and recommended location for thoracocentesis

Answer 87

“Unless there is a reason to go elsewhere, perform thoracentesis at the sixth, seventh, or eighth intercostal space, near the level of the costochondral junction (Fig. 30.5). Clip the selected site and perform a local anesthetic block if needed (this is rarely the case). Aseptically prepare the site, and introduce the needle into the middle of the selected intercostal space. Carefully avoid large vessels associated with the posterior aspect of the rib margins. Advance the needle into the pleural space. Aspirate fluid while the needle is being advanced to allow prompt recognition of the appropriate depth of needle placement. If you feel the heart beating or lungs rubbing across the tip of the needle, withdraw the needle and reassess the situation. With the bevel of the needle facing inward, orient the needle against the rib cage to prevent damage to the lung surface. Gently aspirate fluid and place 5-mL samples in an ethylenediaminetetraacetic acid (EDTA) tube and a clot tube for a cell count and biochemical parameters, respectively. Also, make six to eight direct smears for cytologic evaluation. Submit samples for aerobic and anaerobic cultures.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 88

In what situations (pleural diseases) are bilateral thoracostomy tubes occasionally needed?

Answer 88

“most dogs and cats have a mediastinum permeable to fluid or air, allowing drainage of both hemithoraces through a single tube. The exception to this may be in chylothorax or pyothorax (discussed previously).”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 89

Discuss the pathophysiology of fibrosis pleuritis in dogs and cats

Answer 89

“Fibrosing pleuritis has been reported in dogs and cats secondary to prolonged exudative or blood-stained effusions. In animals with fibrosis, the pleura is thickened by diffuse, fibrous tissue that restricts normal pulmonary expansion (the lungs do not adhere to the body wall in these patients; Fig. 30.16). Exudates are characterized by a high rate of fibrin formation and degradation because chronic inflammation induces changes in the morphologic features of mesothelial cells that cause increased permeability, desquamation of mesothelial cells, and triggering of both pathways of the coagulation cascade. The desquamated mesothelial cells have also been shown to produce type III collagen in cell culture, promoting fibrosis. Additionally, the chronic presence of pleural fluid might lead to impaired fibrin degradation.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 90

Most common complications associated with thoracocentesis and thoracostomy tubes and how to avoid them.

Answer 90

“Although lung penetration and damage are possible with needle thoracentesis, risk is minimal if proper technique is used. The major complication associated with thoracostomy tubes is pneumothorax caused by damage to the tube by the patient (e.g., biting or scratching) or loosening of the connections of the tube to the adapters. Risk of these complications can be minimized by placing a clamp close to the tube’s exit site (see Fig. 30.9), by securing the tube to the adapters (see Fig. 30.11), and by proper bandaging of the chest and tube. Constant surveillance of animals with a thoracostomy tube is recommended. Other complications associated with thoracostomy tube placement are rare but include lung perforation, empyema, laceration of an intercostal vessel, and pulmonary injury caused by aspiration of a portion of lung into a tube drainage port. Risk of lung perforation is related to the type of tube placed and underlying pleuropulmonary disease. If needle thoracentesis or ultrasonography suggests that the fluid is severely loculated or that extensive adhesions are present, surgical or thoracoscopic placement of the thoracostomy tube may be advisable.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 91

You are presented with a case of traumatic diaphragmatic hernia. What considerations should you make regarding the timing of surgical treatment?

Answer 91

“If pulmonary contusions are severe, surgical repair of diaphragmatic hernias should be delayed until the patient’s condition has been stabilized; however, herniorrhaphy should not be delayed unnecessarily. Animals with gastric herniation should be evaluated carefully for gastric distention and should be operated on as soon as they can safely be anesthetized, because acute gastric distention within the thorax may cause rapid, fatal respiratory impairment. Rarely, large diaphragmatic defects require a muscle transposition (e.g., rectus abdominis muscle pedicle flap) or insertion of mesh.4”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 92

Prognosis for surgically-treated diaphragmatic hernias in dogs and cats

Answer 92

“The prognosis is generally excellent if the animal survives the early postoperative period (i.e., 12–24 hours), and recurrence is uncommon with proper technique. In a 2017 study of 96 animals (79 dogs, 17 cats) with acute traumatic diaphragmatic hernias, 79.2% and 83.3% of the dogs and cats, respectively, survived to discharge.5 Of the chronic cases, 100% of the cats (n = 5) and 80.6% (n = 25) of the dogs survived to discharge. Interestingly, an association between the time of the trauma and when surgery was performed did not appear to affect survival, nor was the time between trauma and admission or admission and surgery associated with survival. Increased duration of anesthesia and increased length of time for the surgical procedure were associated with increased mortality. Animals with concurrent injuries were also less likely to survive. Perioperative oxygen dependence was associated with increased mortality.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 93

What is the difference between pulmonary cysts, bulla and bled?

Answer 93

Cysts are closed cavities or sacs lined by epithelium that are usually filled with fluid or semisolid material.

Bullae are nonepithelialized cavities produced by disruption of intraalveolar septa. Maintain a direct connection with the pulmonary parenchyma.

Bleb is a localized collection of air contained within the visceral pleura. Located between the internal and external elastic layers of the visceral pleura.

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 94

What are the most common causes of tracheal rupture in dogs and cats? How is the condition diagnosed and treated? Prognosis?

Answer 94

“Tracheal rupture may occur because of trauma (see Chapter 28). The primary signs of tracheal rupture are pneumomediastinum and subcutaneous emphysema; pneumothorax is less pronounced (Fig. 30.25). Pneumomediastinum in cats is most commonly associated with overinflation of the endotracheal tube cuff1; however, it may also be associated with tracheal damage due to puncture by a stylet during intubation. Other causes of pneumomediastinum in cats include trauma and tracheal foreign bodies. Barotrauma associated with overinflation of the lung, particularly in animals with severe lung pathology, is more likely to lead to pneumothorax than pneumomediastinum. Tracheoscopy is rarely necessary to document/localize tracheal rupture. It is important to distinguish tracheal rupture without pneumothorax from that causing pneumothorax. Tracheal rupture without pneumothorax is best treated by cage rest; tracheoscopy is unnecessary and often only makes the tear worse. Tracheal rupture with pneumothorax, in which the clinician is planning on surgery, may benefit from first performing tracheoscopy to localize the lesion(s). However, it can be difficult to find the site of rupture endoscopically or even at surgery. Fortunately, surgery is rarely indicated as most lesions heal spontaneously with medical management (e.g., cage rest and oxygen supplementation).”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 95

What is the difference in the management of traumatic Vs. Spontaneous pneumothorax?

Answer 95

“Be sure to differentiate traumatic and spontaneous pneumothorax, because the former usually responds to medical management, whereas the latter typically requires surgery.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 96

Spontaneous pneumothorax may be primary (no disease) or secondary. What are the most common causes of spontaneous primary and secondary pneumothorax in dogs?

Answer 96

“Primary spontaneous pneumothorax in dogs may be due to rupture of subpleural blebs; remaining lung tissue may appear normal. These blebs are most commonly located in the apices of the lungs. ”

“secondary (with underlying disease such as pneumonia, pulmonary abscess, neoplasia, chronic granulomatous infection, or pulmonary parasitic infection, such as Paragonimus spp.).”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 97

Most common cause of spontaneous secondary pneumothorax in cats? Management?

Answer 97

“Secondary spontaneous pneumothorax in cats is frequently associated with underlying lung pathology, particularly asthma; however, in some cats other conditions associated with pulmonary pathology (e.g., pulmonary neoplasia, heartworm infection, pulmonary abscesses, lungworm infection) may be found.9 Clinical presentation of cats with asthma-associated spontaneous pneumothorax and that due to other causes is not different and supportive medical management is most appropriate, except in rare cases with focal congenital abnormalities that may benefit from surgical intervention.9”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 98

Dog breed predisposed to spontaneous pneumothorax

Answer 98

Siberian Husky

Question 99

What is the radiographic appearance of pneumomediastinum? Is CT recommended in cases of spontaneous pneumothorax where ruptured bullae are suspected?

Answer 99

“Pneumomediastinum is characterized by the ability to visualize thoracic structures (e.g., aorta, thoracic trachea, vena cava, esophagus) that are not usually apparent on thoracic radiographs. Improved imaging techniques for bullae would be helpful in surgical planning of affected animals; however, in a 2013 study the sensitivity and positive predictive value of CT for bulla detection was low.12 In this study, CT was determined to be an ineffective preoperative diagnostic technique in dogs with spontaneous pneumothorax caused by bulla rupture because lesions were missed or incorrectly diagnosed in many animals unless they were large. False-positive diagnoses are also common.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 100

Describe the intra-op identification and treatment of pulmonary air leakage sites

Answer 100

“Identify and remove diseased lung. If the source of the pleural air is not evident, fill the chest with warmed, sterile saline and look for air bubbles when the anesthetist ventilates the animal. If multiple partial lobectomies are necessary, use an automatic stapling device to reduce operative time. Perform pleural abrasion (mechanical pleurodesis) using a dry gauze sponge. Gently abrade the entire surface of the lung. Before closure, fill the thoracic cavity with warmed fluid and look for air bubbles when the animal is ventilated to ensure that no other air leaks are present. Place a thoracostomy tube and remove residual air before recovering the animal.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 101

Drug and dose administered at induction prior to upper respiratory tract surgery to minimize swelling

Answer 101

“Administer dexamethasone (0.1–0.2 mg/kg IV [intravenous]) at the time of induction to minimize postoperative swelling and edema.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 102

Most common causes of failure of closure of primary or secondary palate

Answer 102

“Incomplete closure of either the primary or secondary palate is attributed to inherited (recessive or irregular dominant, polygenic traits), nutritional (inadequate folic acid), hormonal (steroids), mechanical (in utero trauma), and toxic (including viral) factors”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 103

What spectrum of activity would you look for when choosing antibiotics for aspiration pneumonia? What choices do you have?

Answer 103

“Broad-spectrum antibiotics with efficacy against anaerobes (Box 18.3) are indicated for severe aspiration or purulent rhinitis”

Chloramphenicol (Chloromycetin)
Cefazolin (Ancef, Kefzol)
Enrofloxacin (Baytril)
Ampicillin
Amikacin (Amiglyde-V)
Clindamycin (Antirobe, Cleocin)
Ampicillin Sodium & Sulbactam Sodium (Unasyn)

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 104

Briefly discuss the typical timing, primary goal and realistic expectations for the surgical treatment of patients with primary or secondary cleft palate

Answer 104

“Surgical treatment is generally delayed until the patient is at least 8 to 12 weeks of age to allow growth and easier access to the palate. Older patients seem to have less friable tissue that holds suture better. Palatoplasty performed before 16 weeks of age may hinder maxillofacial growth and development. Although rare, a narrower maxilla and occlusal problems may result. The primary goal of repairing a cleft palate is to reconstruct the nasal floor. Several procedures may be necessary before the entire cleft is permanently reconstructed. This is a hereditary defect; affected patients should be neutered.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 105

Typical radiographic appearance of the lungs in a patient with non-cardiogenic shock caused by electrocution

Answer 105

Bilateral caudo-dorsal alveolar infiltrates

Question 106

Name two alternative but rarely utilized techniques to Arytenoid Lateralization.

Answer 106

Castellated laryngofissure (technically difficult and inconsistent)

Reinervation of the laryngeal musculature (takes too long to provide clinical relief)