Avian Surgery (JTA 5) Flashcards
What are the primary avian flight muscles? What are each of their funcitons?
Label the bones of the wing and the parts of the pytagium.
Anatomy and physiology of the wing
· Primary avian flight muscles are the pectoralis and supracoracoideus
o These muscles accelerate and decelerate the wing btw downstroke and upstroke
o Pectoralis: contracts during downstroke and pronates the wing
o Supracoracoideus: elvates and supinates the wing during upstroke
Describe the anatomy of feathers.
How are primary and secondary remiges numbered? Where do they originate?
Describe feather trimmming as a flight control mechanism.
What are some problems following trimming?
Anatomy and physiology of remiges
· Contour feathers: flight feathers (remiges) and tail (retrices)
· In most species, 10 primary remiges numbered from proximal to distal
· Secondary remiges insert dorsally along ulna and counted distal to proximal
o Vary in number from 6-40
· Follicle grips the feather at the calamus by muscular contraction of the follicular muscle and friction
Wing feather trimming
· Temporary effect after cutting remiges
o Nonpainful
o One or both wings
§ May be helpful to have balance when breeding
o Duration of effectiveness depends on molt
§ 1-2 times /year
· In general all primary remiges are cut
o Cut proximal to the distal tip of the coverts
o May be less likely to chew cut feathers
· African greys may develop keep lesions from hitting substrate after trim
What is brailing?
Describe how is it performed?
Brailing
- Temporarily immobilizing the carpus to prevent flight by using external coaptation
- Applied around the carpus
- Historically used in juvenile pheasants
- Applied once flight feather begin to grow
- Sling should not be in place for more than 3 weeks or may result in wing deformity
- May cause damage to flight feathers
Describe how radial neurectomy is performed to prevent flight in birds.
What are some effects of this procedure?
Is this permananet?
Radial neurectomy
· Radial nerve runs along the medial aspect of the distal humerus
o Only skin covering at that point
o Excision of a portion of the nerve paralyzes the muscles that flex and extend the carpus
· Results in wing droop
· Does not permanently prevent flight
Various tenectomy procedures have been described for deflighting birds.
Describe the effects of tenectomy of the following muscle groups and whether a procedure is recommended?
Extensor Metacarpi Radialis Longus
Adducctor Pollicus Longus and Brevis
Supracoracoideus
Superficial and Deep Pectoralis
Triceps Brachii
TENOTOMY AND TENECTOMY PROCEDURES
- Tenotomy or Tenectomy of the extensor metacarpi radialis longus muscle
- Prevent flight without removing a portion of the wing
- Recommended to perform bilaterally
- Wing droop has been reported although in theory should not develop
- Recommended to immobilize the wing for 6 weeks post op to allow joint ankylosis
- Likely inhibition of extending the carpus was from joint arthrodesis instead
- Tenectomy of the Adductor Pollicis longus and brevis
- Inability to extend the carpus without causing a wing droop
- Inhibits take off and gliding
- Recommended in storks and herons
- Tenectomy of the supracoracoideus muscle
- Not easy to identify
- Located deep to pectoral muscles
- Tendon of insertion passes through triosseal canal at the shoulder formed by the clavicle, scapula, and coracoid bones attaching on the dorsal tubercle of the proximal humerus
- Procedure limited wing extension but did not prevent flight
- Birds with bilateral tenectomy had difficulty righting themselves when placed on their back
- Tenotomy of the superficial and deep pectoralis muscles
- Failed to prevent flight over long term
- Dissection is difficult, birds may regain ability to fly
- Tenotomy of the triceps brachii
- Transection of triceps at the elbow or distal humerus results in severe wing droop
- Not recommended
Describe the procedure of pinioning a bird.
How does this vary for hatchlings and adults?
What species have pneumatic carpometacarpal bones? How does this affect the procedure?
What are some of the complications that may be encountered?
PINIONING
- Act of surgically removing on pinion joint
- Joint of a bird’s wing farthest from the body
- Sx amputation at the carpus
- Usually only performed on one wing-will result in imbalance
- Hatchling birds
- Recommend pinioning of hatchling birds btw 3-10 days old
- Allow to eat and adapt to life outside the egg prior to procedure
- Tip of one wing is cut off with scissors by lifting the alula and positioning the scissor across the carpometacarpus
- Transect proximal to the major and minor portions
- Remove as much of the caudal aspect of the carpometacarpus as possible to remove all primary follicles
- Topical or injectable local anesthetic should be applied
- Site heals by secondary intention
- Alula is left to protect site
- Chicks under parental care may be rejected after pinioning
- In other hatchlings hemorrhage is more likely to be significant
- May want to use a hemostatic clip at an angle under the alula
- Adult birds
- Goal to remove carpometacarpus that the primary remiges are attached to
- General anesthesia and aseptic technique; postoperative analgesia
- Concern re: trauma to the stump
- Bone has very little soft tissue covering, scar tissue does not hold up well to trauma
- May be minimized by covering the stump with normal, feathered skin
- Some birds (pelicans and ground hornbills) have pneumatic carpometacarpal bones
- Transected bone must be covered to prevent aspiration of water
- RAB modified Fletcher technique
- Incision made under or caudal to alula from distal to proximal to the level of the carpus
- Incision continued caudal to alula at the carpus from dorsal then ventral toward cranial edge of joint
- Do not cut skin on the cranial edge near the alula
- Extensor process of the carpometacarpus articulates with the alula
- This projection is cut off to leave it with the alula
- Complications in adults: hemorrhage and shock
- Rec tourniquet
- Single artery supplies the distal wing: ventral metacarpal artery
- Runs along the ventral aspect of the carpus from cranially at the distal radius and radial carpal bone to the minor portion of the carpometacarpus
- Ligate and transect: pass a suture btw major and minor portions of the carpometacarpus
- Rec bandaging post op
Describe the surgical arhtordesis of the wing as a deflighting technique.
How is the carpus arthrodesed?
What about the elbow?
ARTHRODESIS of a wing joint
- Artificial induction of joint ossification btw two bones via surgery
- Generally cartilage on the articular surface must be removed and joint immobilized
- Allow bones to heal as one
- Carpal arthrodesis
- Expose distal ulna, ulnar carpal bone, and proximal carpometacarpus
- Holes are drilled in distal end of the ulna, middle of ulnar carpal bone, and proximal end of the carpometacarpus
- Pass orthopedic wire through three holes and tighten with the carpus in flexion
- For this technique to result in arthrodesis, the articular cartilage would have to be removed and wing immobilized for weeks
- Only useful in large birds
- Not a quick procedure
- Not always successful, often resulted in wing droop
- Elbow
- Medial aspect of the elbow is incised and cartilage removed from distal humerus and proximal ulna
- Close joint capsule
- Pilot hole drilled through distal caudal humerus into proximal ulna at the elbow joint
- Screw placed through distal humerus into proximal ulna
- Time consuming
What is feather extirpation?
How is surgical extirpation performed? How does it vary in large versus small birds? What are some important complications to be aware of?
How is electrosurgical fulguration performed? What are the two methods?
PRIMARY REMIGE FOLLICLE EXTIRPATION
- Extirpation: complete excision or surgical destruction of a body part
- Recently feather follicle extirpation has been recommended as method of choice for deflighting birds
Surgical excision
- All of the germinal tissue must be removed or the feathers will regrow and are generally deformed
- Recommended that blood feathers not be removed until they are hollow
- Extensive hemorrhage even with a tourniquet has been a reported complication
- Smaller birds: single incision is made along minor portion of carpometacarpus
- Skin elevated caudally to expose follicles and each follicle is elevated to completely excise the germinal tissue
- Larger birds: longitudinal incision is made over each of the primary remiges individually to provide exposure to the follicle
- Only proximal 1 cm of calamus and follicle is removed (SEE FIGURE)
- Ventral metacarpal artery must be preserved
- Damage may results in avascular necrosis of the wing distal to the point of thrombosis
- Complications: feather regrowth, excessive hemorrhage, necrosis, infection
Electrosurgical Fulguration
- Electrosurgery: use of electric current passing from a device through the patient and back to the generator
- Destroy= fulgurate
- Cryosurgery
- Liquid nitrogen to freeze tissue resulting in necrosis
- Most commonly requires more than one freeze-thaw cycle, difficult to control the amount of tissue
- Has shown promise for follicle extirpation in pigeons
- Laser
- Diode laser: heat from laser light results in thermal necrosis of the feather follicle
- Wavelength of the light beam produced by the diode laser is absorbed by hemoglobin
- Necrotic tissue must heal by invasion of inflammatory cells following wound healing
- Considered successful in a pigeon study
- Relevant feathers cut at skin level, any dry material within the shaft is removed with forceps
- Laser tip inserted through hollow calamus
- Moved in small circles, activated intermittently to allow cooling of the adjacent tissues until the tip has penetrated the follicle
- Calami of fulgurated follicles are left and shed after necrosis
- No topical medications or bandages are applied to the wing
- 94% success rate in zoo birds in one report
A recent study described the use of acrylic resin prostheses in the treatment of rhinothecal fractures in birds.
What are common causes of rhinothecal fractures in birds?
What are some advantages of using synthetic materials for rhinothecal repair?
Describe your surgical approach to placing a prosthetic on the rhinotheca.
- How do you prevent occlusion of the nares?
Use of acrylic resin prostheses in the treatment of rhinothecal fractures.
Marchio MÂ, Magalhães TV, Minto BW, Dias LG.
Journal of Zoo and Wildlife Medicine. 2022;53(2):480-484.
Background:
- Common causes of rhinotheca fracture: collisions, territorial aggression, metabolic, infectious, congenital disease
- Homologous prostheses are recommended because they maintain function up to 4 years
- Synthetics can be constructed manually during surgery, show greater resistance to forces acting on the beak, have low rejection and infection rates, are low cost, and materials are easy to store
Key Points:
- 2 urethral catheters cut and inserted into nostrils to prevent resin from occluding nostrils
- 2 Steinmann pins inserted in parallel into filed fragment of rhinotheca
– Cockatiel was too small for pins so used T-shaped cerclage wires as a frame for reconstruction
- VIPIFlash colorless resin applied with dental spatulas and formed into beak prostheses
– Prostheses fixed in a way that neutralized all forces acting on the beak, reducing risk of loosening or avulsion
- Immediate return of function (grasping, eating, climbing), good alignment, no complications at 15 mo follow-up (avulsion, torsion, loosening of implant)
- Case selection is important, if beak is still functional prosthetic may not be indicated
- Study the skull anatomy for individual birds because of delicacy of pin insertion
- Weight of synthetic prosthesis should not exceed the weight of the tissue lost from the rhinotheca
