Laryngeal reinnervation

1

• Laryngeal reinnervation
• First described 1989, but largely unsuccessful
• Surgical repositioning and grafting of other
  respiratory accessory muscles/nerve to dorsal
  cricoarytenoideus muscle

2

• 85 successful reinnervation
• Much lower incidence of complications, ie
  pneumonia

3

• Pharyngeal collapse
• Dysfunction of pharyngeal constrictor muscles
  that dilate and stiffen pharynx during
  respiration
• Increased noise during peak expiration
• Exact cause unknown
• Currently no known treatment

4

• Epiglotticentrapment
• Loosesubepi-glottic tissue moves dorsally over
  cartilage
• Impedes air flow
• Surgical laser repair

5

• Facial nerve trauma
• During exercise,nostrils normallyflare
  fromcomma shapeto circular toincreaseair
  flow
• Via primarilycaninus muscle,innervated by
  facial nerve

6

• Facial nerveCN VIIalsoinnervatesothermuscles
  offacial expression, including eyelid, sensory
  to caudal 2/3rds of tongue, lacrimal and salivary
  glands

7

• Neural damage gtcannot flarenostril onaffected
  sideduring exercise
• Fluttering soundduring exercise
• Restricted air flow

8

• Neural damageusually unilateral(one side),lip
  and nostriltowards theunaffectedside
• Possible droopingeyelid, dry eye

9

• Horses can also voluntarily relax the muscles to
  nostrils
• Stops as intensity of exercise increases
• Fluttering sound from both nostrils, never just
  one
• Both nostrils that stops when you increase
  intensity goofing around
• One nostril facial neuropathy

10

• Guttural pouchdisease
• Lots of primarypathology here
• Also causeslots of problemsin nearby
  airwaysdue to the nervesand vasculature in
  close association with guttural pouches

11

• Internal andexternalbranches of thecarotid
  artery
• Maxillaryartery and vein
• Caudal auricularartery

12

• Cranial nerves that course superficially past
  mucosa of guttural pouches
• All function in motor innervation of pharynx,
  larynx or accessory respiratory structures
• IX glossopharyngeal
• X vagus, pharyngeal branch and recurrent
  laryngeal branch
• XI spinal accessory
• XII - hypoglossal

13

• ANY inflammation, infection or irritation in the
  guttural pouches can cause a secondary neuropathy
  in associated nerves and dysfunction of pharynx
  or larynx, and thus an exercise intolerance and
  decrease in performance.

14

• Irritation to nerves can also be iatrogenic
  (caused by the vet) if caustic substances are
  instilled
• Almost anything other than isotonic saline is
  potentially irritating

15

• Empyema (pus)
• Most commonguttural pouch disease
• Primary bacterialinfection, or
• Drainage fromretropharyngeallymph node abscess
• Strep equi
• Guttural pouches can be site of strangles
  chronic carrier infection

16

• Gutturalpouchempyemawithfluidline

17

• Complications of empyema
• Pus from guttural pouch can potentially drain
  into and cause lower respiratory tract infection
• Dysphagia (problems swallowing)
• Higher risk of aspiration pneumonia
• Weight loss

18

• Gutturalpouchmycosis (fungal)
• Erosion ofwall intounderlyingvasculature
• Intermittentepistaxis(nose bleed)

19

• Guttural pouch mycosis
• Infrequent occurance, but serious
• Aspergillus spp most common fungal pathogen
• Size of fungal lesion does not necessarily
  correlate to severity of infection
• 50 of affected horses with epistaxis will die of
  fatal hemorrhage if untreated

20

• Fungallesionsoftenassocdwith
  ananeurysmaldilation ofaffected artery

21

• Surgicalocclusionof bloodvesselscausesspontan
  eousresolutionof fungal lesion within 30-60
  days without further treatment

22

• Mycosis can also be treated with systemic and/or
  topical antifungal meds
• Expensive
• Potentially nephrotoxic
• Potential for phlebitis
• Extended treatment and layup
• (Why shouldnt you exercise this horse?)
• Ongoing risk of fatal hemorrhage