Auer Ch 45 Larynx

Front 1

Relation of The cricoid in the larynx:

Back 1

most caudal, connected to the first tracheal ring by the cricotracheal membrane

Front 2

Relation of the thyroid to the cricoid:

Back 2

rostral, connected by the cricothyroid membrane

Front 3

Relation of the arytenoid cartilages to the cricoid:

Back 3

rostral, right and left arytenoid cartilages articulate with the cricoid at the cricoarytenoid joints

Front 4

Relation of the arytenoid and thyroid cartilages:

Back 4

arytenoid dorsal to the thyroid

Front 5

Function of the cricoarytenoid joint:

Back 5

allow the arytenoid cartilages to rotate dorsolaterally during abduction

Front 6

Location of the cricoarytenoid articulation:

Back 6

caudal aspect of the arytenoid

Front 7

Cartilage composition of the laryngeal cartilages:

Back 7

body of the arytenoid is composed of hyaline cartilage, as is the thyroid and cricoid cartilage. The corniculate processes of the arytenoid is composed of elastic cartilage, as is the epiglottis

Front 8

Relation of the epiglottis in the larynx:

Back 8

most rostral cartilage

Front 9

Relation of the epiglottis to the thyroid cartilage:

Back 9

epiglottis sits on the dorsal surface of the thyroid cartilage, connected by the thyroepiglottic ligament

Front 10

Function of Intrinsic laryngeal muscles:

Back 10

are responsible for movement of the cartilages in relation to each other, changes the diameter of the rima glottis, either by abducting or adducting the corniculate processes of the arytenoids or by increasing or decreasing tension placed on the vocal folds

Front 11

Function of Extrinsic laryngeal muscles:

Back 11

are responsible for movement or stabilization of the larynx as a whole unit

Front 12

What are The vocal folds?

Back 12

mucous membrane covered vocal ligaments

Front 13

Location of vocal ligament:

Back 13

extends from the ventral aspect of the arytenoid to the caudal body of the thyroid and the cricothyroid membrane

Front 14

What are the Intrinsic laryngeal muscles?

Back 14

cricoarytenoideus dorsalis, thyroarytenoideus, cricothyroideus, cricoarytenoideus lateralis, and the tranverse arytenoid

Front 15

How does the transverse arytenoid differ from the other intrinsic laryngeal muscles?

Back 15

It is the only non-paired (right & left)

Front 16

What are the portions of the thyroarytenoideus?

Back 16

rostral portion called the ventricularis, caudal portion called the vocalis muscle

Front 17

What is the major abducting muscle?

Back 17

cricoarytenoideus dorsalis

Front 18

Function of the cricoarytenoideus dorsalis?

Back 18

abduct the corniculate processes and tensing the vocal folds

Front 19

What are the adducting muscles?

Back 19

thyroarytenoideus, transverse arytenoid, and cricoarytenoideus lateralis

Front 20

What is the function of the cricothyroideus?

Back 20

tenses the vocal folds during vocalization

Front 21

What is the innervation to the cricothyroideus?

Back 21

external branch of the cranial laryngeal nerve, which is a branch of the vagus nerve

Front 22

Innervation of cricoarytenoideus dorsalis:

Back 22

recurrent laryngeal nerve, which is a branch of the vagus nerve

Front 23

Innervation of thyroarytenoideus:

Back 23

recurrent laryngeal nerve, which is a branch of the vagus nerve

Front 24

Innervation of cricoarytenoideus lateralis:

Back 24

recurrent laryngeal nerve, which is a branch of the vagus nerve

Front 25

Innervation of tranverse arytenoid:

Back 25

recurrent laryngeal nerve, which is a branch of the vagus nerve

Front 26

What are the Extrinsic laryngeal muscles?

Back 26

thyrohyoideus, hyoepiglotticus, cricopharyngeus, thyropharyngeus, and sternothyroideus

Front 27

What is the aryepiglottic fold?

Back 27

mucous membrane of the epiglottis reflects off the lateral, caudal aspect of the epiglottis to continue with the mucous membrane of the corniculate processes

Front 28

Where is the laryngeal saccule?

Back 28

between the medial wall of the thyroid cartilage and the lateral wall of the ventricle

Front 29

What is the laryngeal ventricle?

Back 29

broad band of tissue that extends from ventral aspect of the arytenoid cartilage to the caudal, lateral border of the epiglottis

Front 30

Laryngeal arterial supply:

Back 30

caudal laryngeal artery and branches of the ascending pharyngeal artery

Front 31

What is Recurrent laryngeal neuropathy?

Back 31

progressive loss of large myelinated axons in the left recurrent laryngeal nerve, resulting in neurogenic atrophy of the intrinsic laryngeal muscles. Paralysis of the cricoarytenoid dorsalis causes loss of abduction, there is increase in the negative inspiratory pressure, reducing the size of the rima glottis

Front 32

Grade 1 laryngeal movement:

Back 32

all arytenoid movement synchronous and symmetrical, and full abduction of the corniculate process can be achieved and maintained

Front 33

Grade 2A laryngeal movement:

Back 33

transient asynchrony, flutter, or delay in movements

Front 34

Grade 2B:

Back 34

asymmetry of the rima glottis most of the time because of reduced mobility of the arytenoid or vocal fold, but with after swallowing or nasal occlusion, full abduction is seen and maintained

Front 35

Grade 3A laryngeal movement:

Back 35

asymmetry of the rima glottis most of the time because of reduced mobility of the cartilage but occasionally after swallowing or nasal occlusion, full symmetrical abduction is achieved but can not be maintained

Front 36

Grade 3B:

Back 36

abductor muscle deficit and cartilage asymmetry and full abduction is never achieved

Front 37

Grade 3C:

Back 37

marked but not total abductor muscle deficit and cartilage asymmetry with little cartilage movement and full abduction is never achieved

Front 38

Grade 4:

Back 38

complete immobility of the cartilage and vocal fold

Front 39

Surgical options for RLN:

Back 39

prosthetic laryngoplasty, ventriculectomy, ventriculocordectomy, reinnervation of the CAD muscle, and partial arytenoidectomy

Front 40

What can be performed in conjuction with PL or reinnervation:

Back 40

VE and VCE

Front 41

Why are VE and VCE performed with PL or reinnervation?

Back 41

reduce noise and scar formation may improve airflow mechanics

Front 42

When is Partial arytenoidectomy performed?

Back 42

congenital malformation of the cartilages, when PL has failed and there is fracture of the cartilage, arytenoid chondropathy

Front 43

Goal of PL:

Back 43

suture is used as a prosthesis between the cricoid and arytenoid cartilages, to have some degree of permanent abduction of the arytenoid

Front 44

Describe PL:

Back 44

10-12 cm incision is made ventral to the linguofacial vein starting 4 cm rostral to the ramus of the mandible. The vein is separated from the omohyoideus muscle, and with retraction of the vein, a plane is evident between the sternocephalicus and cricothyroideus muscles, which is digitally opened. The thyropharyngeus and cricopharyngeus muscles are separated from each other to allow better exposure of the muscular process of the arytenoid. Suture needle is walked off the caudal dorsolateral aspect of the cricoid and the suture is passed in a cranial direction. Suture ends are drawn rostrally under the cricopharngeus muscle and a second suture is placed 1 cm lateral to the first. Suture is passed through the muscular process in a caudomedial to craniolateral direction, with the second suture placed 5 cm more caudal than the first. Suture is tied, leaving 1.5-2cm tails.

Front 45

What procedure can prevent loss of abduction post- PL?

Back 45

tendon of insertion of the CAD can be cut and the cricoarytenoid articulation can be opened and curetted to facilitate ankylosis of the joint

Front 46

When is the tendon of insertion of the CAD cut and the CAJ opened during PL?

Back 46

Prior to placement of suture in the muscular process of the arytenoid

Front 47

What degree of abduction should be the end result of PL?

Back 47

approximately 88% of the maximal rima glottis area for adequate airflow

Front 48

When does training resume after PL?

Back 48

approximately 45 days post-operatively

Front 49

Intra-operative complications of PL:

Back 49

hemorrhage, needle break, perforation of the mucosa, and suture cut through

Front 50

When is perforation of the mucosa during PL most likely to occur?

Back 50

placing the suture in the cricoid cartilage

Front 51

Post-operative complications of PL:

Back 51

seroma, wound infection, dehiscence, dysphagia, coughing, suture infection and contamination of the lower airway resulting in lower airway disease

Front 52

What is initial coughing and dysphagia after PL a result of?

Back 52

excessive abduction or inflammation from retraction on the cricopharyngeus and thyropharyngeus

Front 53

What is the cause of chronic pharyngeal dysfunction after PL?

Back 53

may be due to surgical trauma to nerves or overabduction of the cartilage

Front 54

When should infected PL suture be removed?

Back 54

delayed until at least 4 months after the initial surgery to prevent failure of arytenoid abduction

Front 55

When is repeat PL indicated?

Back 55

overabduction or loss/ failure of abduction

Front 56

Complications of repeat PL:

Back 56

Formation of dense scar tissue makes visualization difficult and transection of scar tissue causes hemorrhage

Front 57

Prognosis after PL:

Back 57

50-70% in racehorses and higher in non-racehorses

Front 58

What is Ventriculectomy (VE)?

Back 58

removal of the mucosal lining of the ventricle/ saccule to help reduce noise and potentially airflow

Front 59

Approaches of VE:

Back 59

laryngotomy approach in either dorsal recumbency after PL or standing

Front 60

Describe VE:

Back 60

laryngotomy is performed, a burr is introduced into the saccule, engaging the mucosa, then everted. The everted saccule is clamped prior to transection with metzenbaum scissors

Front 61

What is VCE?

Back 61

removal of the ventricle and the leading edge of the vocal fold

Front 62

Indications for VCE:

Back 62

sport horses with primary complaint of respiratory noise, with racehorses with grade 3 laryngeal movement caused by vocal fold collapse during exercise, or racehorses that have had PL but have performance limiting issues related to vocal fold collapse

Front 63

Approaches to VCE:

Back 63

laryngotomy approach or through nasal endoscopic laser assisted approach

Front 64

Describe VCE:

Back 64

With laryngoplasty approach, after eversion and removal of the saccule, a 2 cm by 2-3 cm cresent shaped wedge of tissue is removed from the leading edge of the vocal fold. Mucosal edeges are sutured.

Front 65

What is the benefit of suturing the mucosal edges in VCE?

Back 65

decrease hemorrhage, decrease formation of cicatrix, and result in smoother airway surface

Front 66

Describe Laryngotomy:

Back 66

incision is made on ventral midline from just rostral to the thyroid cartilage to just caudal to the cricoid cartilage. The sternothyroideus muscle is separated, and loose adventitia over the larynx is bluntly separated. The cricothyroid membrane is incised

Front 67

What can improve exposure with laryngotomy?

Back 67

cricoid and/ or thyroid can be split

Front 68

Ideal candidates for laryngeal reinnervation:

Back 68

younger horses with grade 3 movement, or those in which performance is not necessary within a year of surgery

Front 69

Source of reinnervation graft:

Back 69

first cervical nerve and the omohyoideus muscle

Front 70

Benefit of 1st cervical nerve and omohyoideus for reinnervation graft:

Back 70

muscle and nerve are active during inspiration

Front 71

Describe reinnervation:

Back 71

laryngotomy, first cervical nerve is identified and followed to insertion in the omohyoideus. Dorsal, surface branches of the nerve are used, and 3 mm grafts are created with tenotomy scissors. Longitudinal separation of fibers in the CAD are made with vascular forceps to create pockets for the grafts. The graft is sutured to the pocket, mainly at the junction of the dorsal and lateral muscle bellies at the caudal aspect of the muscle

Front 72

When does training resume after reinnervation?

Back 72

rested for 16 weeks then return to training for 6 weeks before assessment

Front 73

Reflexes used to determine function after reinnervation:

Back 73

stretching the head and neck to an elevated position and observing a flicker or a single abduction, applying sudden pressure on the commissure of the mouth and observing an abduction

Front 74

What stabilizes The vocal fold?

Back 74

contraction of the cricothyroideus

Front 75

Treatment of Axial deviation of the vocal fold:

Back 75

bilateral VCE

Front 76

Treatment of Bilateral laryngeal paralysis:

Back 76

aimed at the underlying disease, but in unresponsive cases a unilateral PL can be performed as a salvage procedure in non-performance horses or trachestomy can be considered in horses that need to have some athletic capabilities

Front 77

Portions of larynx derived embryologically from the 4th branchial arch:

Back 77

Lateral wings of the thyroid, cricoarytenoid articulation, crcithyroideus, thyropharyngeus, and cricopharyngeus muscles

Front 78

What is the side predilection for 4BAD?

Back 78

Right side is more commonly affected than the left and bilateral involvement is more common than left sided disease

Front 79

What palpable abnormalities occur with 4BAD?

Back 79

thyroid wing is absent or decreased in size, and there is a gap between the cricoid and thyroid cartilage because there is absence or atrophy of the cricothyroideus muscle

Front 80

What is often observed endoscopically with 4BAD?

Back 80

rostral displacement of the palatopharyngeal arch, where the caudal pharynx is displaced rostral to the dorsal aspect of the corniculate processes

Front 81

Treatment for Axial deviation of the aryepiglottic folds:

Back 81

transendoscopy laser transection or laryngotomy resection of a 2 cm section of tissue that is collapsing into the airway

Front 82

What is Arytenoid chondropathy?

Back 82

abnormal enlargement in 1 or 2 arytenoid cartilages, usually due to mucosal injury and subsequent infection, but may be multifactorial

Front 83

Why is abduction restricted with ACC?

Back 83

lateral position of the thyroid cartilage and inflammation in the CAJ and/ or CAD

Front 84

Endoscopy signs of ACC:

Back 84

granulation tissue, fistulas or sinus tracts, and ulceration or granulation opposite to the original granulation lesion

Front 85

Types of arytenoidectomy:

Back 85

Subtotal arytenoidectomy removes all of the cartilage except for the muscular process and the corniculate process. Partial arytenoidectomy is removal of all of the arytenoid except for the muscular process

Front 86

Which type of arytenoidectomy is preferred and why?

Back 86

Partial is preferred because subtotal has been shown to not improve upper airway function

Front 87

What approach to arytenoidectomy should be taken with bilateral ACC?

Back 87

worst side is removed with partial arytenoidectomy

Front 88

When is Bilateral arytenoidectomy performed?

Back 88

salvage procedure.

Front 89

Describe partial arytenoidectomy:

Back 89

laryngotomy, U shaped incision is made on the axial surface of the arytenoid and the mucosa is undermined off of the cartilage. The cartilage is elevated and transected with Mayo scissors or a scalpel.

Front 90

What is a modified partial arytenoidectomy approach?

Back 90

removal of the portion of the arytenoid in 2 pieces with its overlying mucosa. The defect is closed by suturing the remaining mucosa and the aryepiglottic fold

Front 91

Benefits of modified partial arytenoidectomy?

Back 91

easier dissection, shorter surgery time, reduces soft tissue in the airway, and is equal in post-operative complications and airflow mechanics achieved with the traditional approach

Front 92

Complications of partial arytenoidectomy:

Back 92

Dyspnea and dysphagia are the most common, Intraluminal granulation and advanced mineralization of the cartilages

Front 93

Disorders of the epiglottis:

Back 93

entrapment in the aryepiglottic fold, acute epiglottitis, subepiglottic cyst or granulomas, dorsal epiglottic abscesses, hypoplasia, and retroversion

Front 94

When does Epiglottic entrapment occur?

Back 94

loose subepiglottic tissue becomes displaced dorsal to the soft palate

Front 95

What is associated with epiglottic entrapment?

Back 95

entrapment is persistent, and usually the tissue is thickened. Epiglottic entrapment may be associated with epiglottic hypoplasia

Front 96

Treatment options for EE:

Back 96

transnasal endoscopic guided laser, bistoury, or electrocautery axial resection of the membrane, bistoury transection through an oral approach or excision through a laryngotomy or pharyngotomy

Front 97

Recurrence rate Laser assisted EE transection:

Back 97

4-10%

Front 98

Complications Laser assisted EE transection:

Back 98

thermal trauma to the epiglottis

Front 99

recurrence rate bistoury EE transection:

Back 99

5-15%

Front 100

Complications bistoury EE transection:

Back 100

laceration of the soft palate, epiglottis, or pharynx

Front 101

Recurrence rate Transnasal endoscopic guided electrosurgical EE transection:

Back 101

40%

Front 102

When is laryngotomy EE transection used?

Back 102

reserved for very thickened, ulcerated, and fibrotic appearing entrapments

Front 103

Possible sequella of relief of epiglottic entrapment, regardless of surgical approach taken:

Back 103

DDSP

Front 104

Endoscopic appearance of acute epiglottitis:

Back 104

thickened, reddened, edematous mucous membrane of the epiglottis

Front 105

Origin of Subepiglottic cysts:

Back 105

submucosal in origin

Front 106

Histology of subepiglottic cysts:

Back 106

stratisfield and pseudostratisfied columnar epithelium with mucous glands, ducts, and eosinophilic mucous

Front 107

Treatment options for subepiglottic cysts:

Back 107

removed through a laryngotomy approach, transorally using a laser or a cyst snare, and transnasally using laser or electrosurgery. A single report of cyst injection of 10% formalin resulting in resolution.

Front 108

When is transnasal approach to subepiglottic cyst chosen?

Back 108

small cysts that are easily manipulated

Front 109

Location of Subepiglottic granulomas:

Back 109

form on the ventral aspect of the epiglottis

Front 110

Cause of subepiglottic granulomas:

Back 110

inflammation and ulceration of the aryepiglottic fold

Front 111

What is the most important aspect of treating subepiglottic granulomas?

Back 111

extended periods of rest are mandatory

Front 112

Treatment of Epiglottic hypoplasia:

Back 112

epiglottic augmentation, submucosal injection of polytetrafluoroethylene (Teflon)

Front 113

How does Augmentation affect the epiglottis?

Back 113

increased thickness but not increased length

Front 114

What is the cause of Epiglottic retroversion?

Back 114

Trauma or inflammation of the geniohyoid or hypoglossal nerves

Front 115

Treatment options for epiglottic retroversion?

Back 115

attempts have been with epiglottic augmentation, placement of a prosthetic suture between the epiglottis and thyroid cartilage

Front 116

Back 116

vocal fold collapse

Front 117

Back 117

rostral displacement of palatopharyngeal arch in 4bad

Front 118

Back 118

axial deviation of aryepiglottic folds

Front 119

Back 119

after resection of aryepiglottic folds

Front 120

Back 120

arytenoid chondritis

Front 121

Back 121

arytenoid chondritis

Front 122

Back 122

left = subtotal right = partial

Front 123

Back 123

epiglottic entrapment

Front 124

Back 124

epiglottic entrapment

Front 125

Back 125

ulcerated epiglottic entrapment

Front 126

Back 126

epiglottic hypoplasia

Front 127

Back 127

epiglottic retroversion

Front 128

Back 128

grade 4 RLN

Front 129

Back 129

moderate abduction (grade 2) after prosthetic laryngoplasty

Front 130

Back 130

excessive abduction (grade 1) after prosthetic laryngoplasty

Front 131

Back 131

exercise videoendoscopy grade 4 RLN with vocal fold collapse