1 ce avian diagnostic endoscopy - amazon s3 · assessing the avian reproductive tract for many...

E ndoscopy is the internal examination ofstructures and organs using an endoscopeor telescope and has become a useful diag-

nostic tool in human and veterinary medicine.1,2

In zoological medicine, the application of diag-nostic endoscopy has shown great promise in avariety of species but has probably been mostaccepted in avian medicine.3–9 Avian endoscopyhas evolved since the 1970s and includes coe-lioscopy, tracheoscopy, gastrointestinal endoscopy,and, more recently, endosurgery.

This technology allows clinicians to examineand sample the internal organs of birds via a sin-gle, small surgical incision. The benefits include:

• Minimally invasive internal examination

• Rapid and reliable biopsy techniques

• Avoiding invasive, lengthy surgery

aDr. Stephen J. Hernandez-Divers has conductedresearch funded by Merial on the pharmacokineticsof meloxicam in iguanas. Karl Storz Veterinary

Endoscopy (Goleta, GA) suppliesequipment to the University ofGeorgia, but neither Dr. StephenJ. Hernandez-Divers nor theUniversity of Georgia receivespayment from the company.

Article #1

ABSTRACT:

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Most companion birds do not tolerate invasive diagnostics or surgery as well as compan-ion mammals. However, the ability to evaluate and sample internal structures and organsfor histopathology and microbiology is key to making a definitive diagnosis.This is partic-ularly true for exotic birds in which reliable and validated pathognomonic clinicopatho-logic data may be lacking. The ability to examine and sample using fine-diameter tele-scopes allows clinicians to make a diagnosis using a minimally invasive single-entrytechnique.This article summarizes the benefits of diagnostic rigid endoscopy in compan-ion birds.

Avian veterinarians have been endoscopicallyassessing the avian reproductive tract for manyyears, and despite the advent of DNA probesfor sex identification of many species, cliniciansinvolved with breeders, wholesalers, or retailersmay still be asked to perform this service.3 Overthe past 20 years, endoscopy has become morepopular and an important tool for antemortemdisease diagnosis; more recently, endoscopy hasalso evolved into a means of minimally invasivesurgery.6,10 The ability to exploit the air sac sys-tem of birds enables endoscopists to visualizemost, if not all, of the major organs of clinicalinterest, including the liver, lungs, air sacs,heart, kidneys, adrenal glands, spleen, pancreas,gonads, oviduct, shell gland, and intestinal tract.In addition, the oral approach permits examina-tion of the oral cavity, esophagus, crop, proven-triculus and ventriculus, glottis, and tracheadown to the level of the syrinx. The cloacal(vent) approach permits examination of thecloaca and openings to the shell gland andureters.

A modern rigid endoscopy system costs$10,000 to $20,000, representing a capitalinvestment similar to that of ultrasonography or

November 2004 839 COMPENDIUM

Avian Diagnostic Endoscopy

Stephen J. Hernandez-Divers, BVetMed, CBiol, MIBiol, DZooMed, MRCVS, DACZMa

Sonia M. Hernandez-Divers, DVM, DACZMUniversity of Georgia

radiography. Like most diagnostic imaging modalities,rigid endoscopy has multispecies appeal, with extensiveapplications in mammals (including dogs, cats, rabbits,ferrets, and rodents), reptiles, amphibians, and fish.Therefore, it is a practical, affordable, and versatile toolfor companion animal practice.

This article has been written with the general practi-tioner in mind, and only the most commonly employedavian diagnostic techniques have been described. For amore extensive description, readers should consult thereferences, which have been specifically limited to scien-

tific conferences, established texts, and peer-reviewedjournals to minimize anecdotal information.6,10,11

EQUIPMENTRigid Endoscope

The compact body size of most companion avianspecies coupled with their coelomic air sac body designmakes them ideally suited to rigid endoscopy.6 Tra-

ditional rigid endoscopes incorporated a convex glasslens system in which small glass lenses were separatedby larger air spaces. In contrast, the modern rod lens tel-escope, invented by Professor Harold Hopkins of Eng-land, uses comparatively longer rods of glass and smaller

air spaces. The advantages of this rod lens design aregreater light transmission, better image resolution, awider field of view, and image magnification.12 We haveused various makes and models but think that rod lensscopes are superior; we currently prefer the systemdesigned by Karl Storz Veterinary Endoscopy forhuman cystoscopy and modified by Taylor for birds5,12

(available commercially; see box on page 840). The Tay-

COMPENDIUM November 2004

Avian Diagnostic Endoscopy840 CE

Figure 1. Basic 2.7-mm rigid endoscopy system. A 2.7-mm telescope housed within a 14.5-Fr operating sheath, with alight guide cable and an endovideo camera attached (A). Close-upof the end of the operating sheath illustrating biopsy forcepsprotruding from the instrument channel (B). Five-Fr endoscopicinstruments used with the 14.5-Fr operating sheath (C): graspingforceps (1), biopsy forceps (2), aspiration or injection needle (3),and single-action scissors (4). (B and C are courtesy of Karl StorzVeterinary Endoscopy)

• Hopkins telescope (2.7 mm × 18 cm, 30˚)• Operating sheath (5-Fr), instrument channel, and

two ports (14.5 Fr)• Examination and protection sheath (3.5-mm outer

diameter)• Cleaning brushes and instrument lubrication oil• Nova xenon light source (175 W)a

• Light guide cable (3.5 mm × 230 cm)• Biopsy forceps (5 Fr)• Scissors (3 Fr)• Fine aspiration or injection needle with Teflon guide• Grasping forceps (5 Fr)• Wire retrieval-basket forceps (5 Fr)• Veterinary video camera (cold and gas sterilizable)• Medical-grade monitor• Documentation (e.g., videocassette recorder, digital

recorder, still-image printer)• Mobile cart for storing equipment

aA halogen light source can be used if performing endoscopyonly on animals weighing less than 4.4 lb (2 kg). However, ifconsidering the procedure for larger species (e.g., dogs andcats), xenon is a better investment.

Recommended 2.7-mmRigid Endoscopy Equipment

Definitive diagnosis of avian disease often requires demonstrationof a host response by cytology or histopathology and, if the

disease is infectious, identification of the offending pathogen.

A

B

C

1 2 3 4

lor modification of the operating sheath permits the tel-escope tip to protrude approximately 2 mm past the ter-minal end of the sheath. The advantages of this are eas-ier penetration of the air sacs when using the leadingedge of the exposed telescope and the ability to cleanthe terminal lens of the telescope by gently wiping itagainst a membrane. However, if a practitioner is likelyto perform endoscopy in mammals or reptiles, theunmodified sheath that encompasses the entire lengthof the telescope may be preferable because the dangersof mucosal laceration and tissue damage are reduced.

The system consists of a 2.7 mm × 18 cm Hopkinstelescope with a 30˚ oblique view. This angle allows notonly a straight-ahead view but also, by simply rotatingthe telescope around its longitudinal axis, a greater field

of vision than a telescope with a 0º angle. The 2.7-mmtelescope can be used with a 3.5-mm protection sheathor a 14.5-Fr operating sheath. The operating sheathprovides two stopcocks for gas or fluid insufflation, aspi-ration, and irrigation as well as a 5-Fr channel for vari-ous endoscopic instruments. The most useful instru-ments are scissors, grasping forceps, biopsy forceps, afine aspiration or injection needle, and a wire retrievalbasket (Figure 1). The flexible biopsy forceps are usefulin harvesting tissue samples for histopathology andmicrobiology. The small sample size permits collectionof several biopsy specimens for multiple tests, sequentialbiopsies to monitor progress, and endoscopic biopsytechniques in patients weighing less than 100 g. Thefine aspiration or injection needle can be used for

November 2004 COMPENDIUM

Avian Diagnostic Endoscopy 841CE

Endoscopy tower with all required equipment, including the monitor (1),digital documentation and printer (2),camera base-unit (3), light source (4),and carbon dioxide endoflator (5).

1

2

3

4

5

Monitor

InstrumentsRadiosurgery

or laser

Anesthesia

Light sourceInsuff latorCamera

Digital recorder

Figure 2. Endoscopy room preparation.

Operating room layout for avian coelioscopy. (Illustration by Mr. Kip Carter, EducationalResources, University of Georgia)

documentation equipment shouldall be placed on a mobile cart thatcan be easily moved around thehospital. This promotes use ofendoscopy in the examination,procedural, and operating roomsand ensures appropriate position-ing for maximizing surgeonergonomics (Figure 2).

Telescope, Sheath, andInstrument Preparation

It is essential to use properlycleaned and sterilized equipmentto prevent postsurgical infection.Equipment should first becleaned using a neutral pH enzy-matic cleaner, ensuring that allstopcocks and channels havebeen thoroughly scrubbed withappropriate brushes. Instrumentsshould be regularly lubricated

using instrument oil. Autoclaving is seldom recom-mended (although modern autoclavable telescopes areavailable) because the longevity of the equipment maybe reduced. The two practical options are gas (e.g., eth-ylene oxide or hydrogen peroxide) or cold (e.g., 2% glu-taraldehyde solution) sterilization. Endoscopic equip-ment should not be soaked in any solution for morethan 30 minutes, and the manufacturer’s recommenda-tions should always be followed. Plastic telescope pro-tectors as well as dedicated storage and sterilizationcontainers can help minimize the risks to equipment.

ENDOSCOPY TECHNIQUESAnesthesia

Examination of the oral cavity and cloaca may be pos-sible in a conscious or sedated patient with a mouth gagor other appropriate restraint, but we prefer generalanesthesia to reduce the risk of damage to the equip-ment and injury to the patient and staff. Performingcoelioscopy on conscious birds is no longer tenable, andgeneral anesthesia is required for all surgical procedures,including endoscopy.3 Isoflurane or sevoflurane admin-istered by facemask, followed by intubation, is the normfor psittacines, although anesthesia should be main-tained via an air sac tube when performing prolongedtracheoscopy. For a complete description of avian anes-thesia, current reviews should be consulted.13,14

remote aspiration, irrigation, and drug administration.The grasping forceps are useful for manipulation of tis-sues, debridement, and foreign body retrieval, althoughthe wire retrieval-basket forceps may be better suited forlarger items. A smaller 1.9-mm telescope with an oper-ating sheath that can accommodate 3-Fr instruments isalso available and is particularly suited to birds weighingless than 150 g.

Light Sources, Cameras, andDocumentation

Two major types of light source are available: the lessexpensive tungsten halogen and the more expensive rare-earth xenon. Halogen is sufficient for rigid endoscopywhen using the eyepiece, but xenon is preferred forvideoendoscopy or documentation and is essential for ani-mals heavier than 4.4 lb (2 kg). The light source is con-nected to the endoscope via a flexible fiber-optic cable.The efficiency of light transmission is reduced as cablelength increases. A xenon light source with a dedicatedendoscopy camera and some form of documentation capa-bility (e.g., videocassette recorder, digital video recorder,digital still image capture, still image printout) is recom-mended for case records and client education.A common mistake in practice is to store endoscopyequipment in its shipping container, making it impracticalto use frequently. The monitor, camera, light source, and



Figure 3. Patient positioning and technique for left-sided avian coelioscopy.(Illustration by Mr. Kip Carter, Educational Resources, University of Georgia)

The bird should be positioned in right lateralrecumbency with its wings dorsal and pelvic limbcranial to expose the flank.

Close-up of the surgical site demonstratinginsertion of the sheathed telescope (T)behind the last rib (arrow), just ventral to theflexor cruris medialis muscle (F).The pubis(P) is the third anatomic landmark.

F

PT



Coelioscopy (Laparoscopy)There are four basic approaches to the coelom: left,

right, ventral, and interclavicular. Physical examination,diagnostic imaging (including radiography and ultra-sonography), and clinical pathology should be used toidentify the most appropriate approach. For example, thespleen is best visualized via a left approach and thepsittacine pancreas from the right, and more of the livercan be seen from a ventral approach.6

There are few contraindications for endoscopy, butinsurmountable anesthetic risks are an obvious example.In addition, gross obesity and large masses or otherspace-occupying lesions that severely compress or obliter-ate the air sacs can greatly hamper coelioscopy. Left orright approaches should be avoided in birds with ascitesbecause fluid leakage into the air sac system is almostunavoidable; however, in such cases, a ventral midlineapproach into the hepatoperitoneal cavities is practical.6

The left approach to the coelom is most commonly

Cranial division of the kidney(K), pigmented testis (T), andadrenal gland (A) in animmature cockatoo.

Cranial division of the kidney(K), ovary (O), and adrenalgland (A) in an immaturefemale Amazon parrot.

Cranial division of the kidney(K), ovary (O), adrenal gland (A),and dorsal ovarian ligament(arrow) in a mature femaleAfrican grey parrot.

Cranial (Ka) and middle (Kb)divisions of the kidney separatedby the external iliac vein (whitearrow), testis (T), ureter, and vasdeferens (black arrow) in amature pigeon.

Figure 4. Coelioscopic evaluation of avian gonadsviewed from within the left abdominal air sac.

K

TA

Ka

T

Kb

K

OA

K

OA



used because the female reproductive organs are locatedon the left side of most avian species. The bird shouldbe positioned in right lateral recumbency with its wingssecured dorsad over its back using self-adhesive tape. Toexpose the left flank, the left pelvic limb should bepulled craniad and secured to the neck using a self-adhesive bandage. The entry site is located immediatelybehind the last rib and just ventral to the flexor crurismedialis muscle as it courses from the caudal stifle tothe ischium (Figure 3). Very few feathers, if any, need to

Caudal ventriculus (V), testis(T), and spleen (S) observedfrom the left abdominal air sac in a common pigeon.

Proventriculus (P), liver (L), andcranial membrane of the caudalthoracic air sac (A) observed fromthe left caudal thoracic air sac inan Amazon parrot.

Figure 5. Avian coelioscopy.

Intestinal loops observed fromthe left abdominal air sac in aneclectus parrot.

Pancreas (P) and duodenum(D) observed from the right abdominal air sac in an Amazon parrot.

Middle (Kb) and caudal (Kc)divisions of the kidney and theureter (arrow) observed fromthe left abdominal air sac in amale cockatoo.

Dilated proventriculus (P), liver(L), and heart (H) observed from the left cranial thoracic air sac in a cockatoo withproventricular dilation disease.

P

LH

PL

A

V

T

S

KbKc

D PP



be plucked before aseptically preparing the area. Follow-ing a 2- to 4-mm skin incision, straight hemostatsdirected in a slight craniodorsal direction should be usedto bluntly dissect between the thin subcutaneous tissuesand enter the caudal thoracic air sac. The hemostatsshould be replaced by the sheathed telescope, and cor-rect position within the caudal thoracic air sac should beconfirmed by identifying the lungs (straight ahead), cra-nial thoracic air sac (to the left), abdominal air sac (tothe right), caudal edge of the liver and proventriculus(ventral), and ribs and intercostal muscles (dorsal).Adjacent air sacs can be explored by pressing the tip ofthe telescope against the proximal air sac membrane andadvancing the telescope in a sweeping motion until theair sac membranes are breached. Normal membranes aretransparent, and tissues in the adjacent air sac can be

visualized and avoided. Great care is required whenbreaking through thickened opaque air sacs becausevision is impaired and trauma can occur if the telescopeis blindly advanced. The lungs, liver, heart, and associ-ated great vessels can be examined from the cranial tho-racic air sac, whereas the genitourinary system, intestine,spleen, adrenal gland, and associated vasculature can bevisualized from the abdominal air sac (Figures 4 and 5).There is no need to repair the small holes punctured in

the air sac membranes because they generally healwithin 10 days. Postoperative subcutaneous emphysemamay be seen in some birds when only skin closure hasbeen performed. Therefore, a single absorbable (i.e.,polyglactin or polydioxanone) suture incorporating thebody wall and skin is recommended.6

The right approach to the coelom is essentially thesame as the left approach. Of particular note is the asym-metric location of the psittacine pancreas, which can beaccessed from the right abdominal air sac6 (Figure 5).

The ventral approach to the coelom provides excellentaccess to much of the liver. In cases of ascites, the ventralapproach is preferred because the telescope can enter thehepatoperitoneal cavities without penetrating an air sac.The bird should be positioned in dorsal recumbency, andfollowing aseptic preparation, the ventral midline should

be entered just caudal to the keel (Figure 6). Thehepatoperitoneal cavity is divided into left and right sides,and the midline membrane can be perforated as previouslydescribed.6

To identify and preserve the crop, a larger (1 cm) sur-gical approach (the interclavicular approach) is re-quired in the midventral coelomic inlet with the bird indorsal recumbency. The telescope must be carefullyadvanced because of the close proximity of major car-

Most companion birds do not tolerate invasive procedures aswell as domestic mammalian pets.

Figure 6. Ventral midline approach to the ventralhepatoperitoneal cavities and liver in a cockatiel using a2.7-mm telescope and 14.5-Fr sheath.

Figure 7. Interclavicular approach to the coelomic inlet inan Amazon parrot using an unsheathed 2.7-mm telescope.



diovascular structures in this region (Figure 7). Theinterclavicular approach is less commonly used but doesprovide access to the syringeal region, heart, and greatvessels and has been useful in identifying, sampling, andtreating cranial coelomic masses.15

Biopsy TechniqueOne of the great benefits of endoscopy is that when

an abnormal structure or pathologic lesion is observed,

biopsy specimens can be taken under direct visual con-trol. Biopsy specimens can be harvested from the kid-neys, gonads, liver, spleen, pancreas, lungs, fat, air sac,coelomic musculature, and generally any abnormal softtissue structure. It is important to examine as much ofthe target structure as possible to determine whetherpathology is focal, multifocal, or diffuse. In cases of dif-fuse renal or hepatic disease (e.g., tubulonephrosis,nephrocalcinosis, hepatic lipidosis, hepatitis), two orthree biopsy specimens taken from the most convenientsites are generally diagnostic. Ultrasound-guided andblind-percutaneous biopsy techniques may be equallyeffective in diagnosing diffuse disease. However, poorervisualization of closely associated structures makes iatro-genic trauma more likely. Most diagnostic failures occurbecause of poor tissue selection for biopsy, and this isespecially true when dealing with focal (e.g., abscess,neoplasia, cyst) and multifocal (e.g., pyogranulomata,mycobacteriosis) diseases. In these cases, direct endo-scopic visualization offers the best chance of sampling

the most appropriate area(s). In cases of focal or multi-focal disease, single or multiple discrete lesions are visi-ble and biopsy specimens should ideally be harvestedfrom the edge of the lesion, taking normal and abnor-mal tissue in the same biopsy sample for both microbi-ology and histology. For a technically easier alternative,small biopsy specimens can be collected from the abnor-mal and normal areas and submitted together for com-parison. Although rare, focal disease deep within an

organ and showing no surface lesions may be missedduring endoscopic examination. It is important to corre-late histopathologic and microbiologic biopsy resultswith clinicopathologic data when dealing with organdisease. It is often surprising how biopsy results providea definitive diagnosis even in the face of unremarkableclinicopathologic data.

When confronted by a potentially cystic lesion orabscess, it is safer to first attempt drainage using fine-needle aspiration rather than risk postbiopsy leakageinto the air sacs or coelom. When attempting to per-form a liver, lung, or testicular biopsy from the left orright approach, it is preferable to first incise the air sacand serosal membranes using endoscopic scissors. Thisprovides better access to the tissue parenchyma andyields biopsy samples of superior histologic qualitywith minimal artifacts. Biopsies of the spleen, kidneys,adrenal gland, and most pathologic lesions can usuallybe performed without using scissors. The biopsy in-strument should be passed through the operating chan-

Cranial division of the kidney,illustrating urate deposits belowthe capsule.

Advancement of the biopsyforceps–sheath–telescope unittoward the kidney.

Gentle closure of the biopsyforceps.

Postbiopsy site with minimalhemorrhage.

Figure 8. Kidney biopsy viewed from the left abdominal air sac in an Amazon parrot.

Early diagnosis of avian disease directs appropriate casemanagement and helps maximize clinical success.



ing. Postsampling hemorrhage tends to be inconse-quential because of the avian extrinsic coagulationpathway and, in particular, tissue-associated thrombo-plastin.16 As an example, approximately 500 endoscopicsplenic biopsies were performed in research pigeons atthe University of Georgia without a single serioushemorrhagic incident.17

In cases of diffuse liver pathology, the most accessi-ble sampling site is the caudal edge of the liver, locatedon the ventral floor of the caudal (or sometimes cranial)thoracic air sac. To access the liver, it is necessary toincise the air sac and hepatoperitoneal membranesusing scissors that have one fixed and one movableblade. The scissors should be opened and the fixedblade gently inserted through the membranes parallelwith the caudal edge of the liver. While keeping theblades open, the scissors–sheath–telescope unit shouldbe elevated and advanced to extend the incision. Oncethe incision is large enough to introduce biopsy forceps,the blades should be closed and the scissors retracted.Biopsy forceps should then be inserted through theincision, and a clean liver sample can be collected (Fig-ure 9). Multiple biopsy samples can be taken from thesame site.

Renal biopsy specimens are most easily collectedfrom the cranial division of the kidneys but can also beharvested from the middle and caudal divisions. In gen-eral, there is no need to use scissors because the renal

parenchyma protrudes into the abdominal air sac and iseasily accessed.

Lung tissue is most accessible from the left or rightcaudal thoracic air sacs. The air sac and pleural mem-branes must first be incised using scissors. It is generallyeasier to rotate the scissors within the operating channelso that the fixed blade is dorsal. The scissors–sheath–tele-scope unit should be advanced and the point of the fixedblade inserted through the membranes covering thelungs. The scissors–sheath–telescope unit should then begently moved ventrad, creating a dorsoventral incisionthrough which biopsy forceps can be inserted to collectlung biopsy specimens.

The spleen can be best visualized from the leftabdominal air sac, and although greater hemorrhage is

Figure 9. Liver biopsy from the left caudal thoracic airsac in an eclectus parrot. It is necessary to incise the over-lying caudal thoracic air sac and ventral hepatoperitoneal cavitymembranes (M) for the biopsy forceps (B) to sample the liver (L).

B

L

M

nel of the sheath and into the endoscopic field. Theforceps should be advanced until they are in the centerof the field of view and the opening and closing mech-anism is unhindered by the sheath. The instrument–sheath–telescope unit should be advanced as a singleinstrument. Attempts to move the forceps independ-ently of the sheath tend to create erratic, uncontrolledmovements inside the bird. When immediately in frontof the organ or tissue of interest, the biopsy jaws

should be opened and the instrument–sheath–telescopeunit advanced to the tissue. Sharp, well-maintainedbiopsy forceps close automatically when the handle isreleased and harvest excellent tissue samples with onlyminimal, if any, additional force (Figure 8). The biopsyforceps should be removed from the sheath, ensuringthat the instrument is withdrawn in straight alignmentwith the operating channel. Delicate biopsy samplesare best removed from the forceps by rolling them ontomoistened cotton-tipped applicators and sandwichingthem between the foam inserts of a biopsy cassette.Biopsy cassettes, available from any pathology service,reduce the chances of tissue damage and loss duringsubmission. Tissue samples may also be submitted formicrobiologic culture and antimicrobial sensitivity test-

Endoscopy facilitates minimally invasive collection of diagnostic samples in birds.



usually associated with biopsy, the clinical consequencesappear minimal.17

Pancreatic biopsy specimens are most easily collectedfrom the right abdominal air sac of psittacines.

TracheoscopyThe lower respiratory tract can be evaluated using the

left and right approaches to the air sacs and lungs. How-ever, to complete the respiratory examination, an oralapproach to the choanae, trachea, and syrinx and anexternal approach to the nares are required. Parrots thatare severely dyspneic or suddenly lose their voice andpresent in acute respiratory distress must first be stabi-lized. Oxygen and, when necessary, an air sac tube toprovide an alternative airway should be used. Gas anes-thesia can be delivered by an air sac tube, leaving themouth and trachea clear for endoscopy, biopsy, anddebridement. In birds heavier than 400 g (e.g., Amazons,African greys, macaws, cockatoos), a 2.7-mm telescopeshould be used to allow tracheoscopy (Figures 10 and

11). In smaller birds, a 1-mm semirigid endoscope or1.9-mm telescope is required. The 1.9- and 2.7-mm tel-escopes can be used without a sheath; however, theadvantages of reduced diameter should be weighedagainst increased risks of damaging the telescope. Withthe bird in dorsal (preferred) or ventral recumbency andits head and neck extended, the telescope can be insertedthrough the glottis and into the trachea. A surgical planeof anesthesia is required to prevent coughing, but irrita-tion and mucosal damage can be reduced by raising theleading edge of the 30˚ telescope above the mucosal sur-face while advancing it down the trachea. Even when thetracheal diameter prevents use of a sheathed telescope,retrieval and biopsy forceps can be inserted alongside thetelescope for retrieval of foreign bodies, debridement,and sample collection.

Gastrointestinal and Cloacal EndoscopyExamining the oral cavity, esophagus, crop, proven-

triculus, and ventriculus is possible in most birds weigh-

Figure 10. Avian tracheoscopy.

Tracheoscopy using an unsheathed 2.7-mm telescope in a barnowl in dorsal recumbency.

Tracheoscopy using an unsheathed 2.7-mm telescope in anAfrican grey parrot in ventral recumbency.

View of the distal tracheademonstrating almost completeocclusion of the lumen by whiteamorphous material andadvancing biopsy forceps.

Perioperative view illustratingpartial debridement of the lesionand revealing the syrinx below.Microscopic examination ofremoved material revealed fungalelements, and samples weresubmitted for fungal culture.

Postoperative view illustratinguse of an endoscopic injectionneedle with a Teflon guide todeliver amphotericin B directlyinto the distal trachea andsyrinx.

Reexamination of the distaltrachea and syrinx 10 days afterinitial surgery and itraconazoletherapy.Based on this examination,medication was stopped and thecondition did not recur.

Figure 11. Tracheoscopy of a cockatoo that presented with acute dyspnea.



When cadavers are the only available option, addi-tional instruction from an experienced endoscopistwho has worked with live birds is recommended. Incountries that permit and regulate the use of live ani-mals for training veterinarians, nonrecovery endo-surgery laboratories using anesthetized pigeons offeran unparalleled opportunity for establishing compe-tence before managing clinical cases. Such courses areoffered regularly by the University of Georgia, theAssociation of Avian Veterinarians, and continuingeducation meetings throughout the United States andEurope.

ACKNOWLEDGMENTSThe authors thank Karl Storz Veterinary Endoscopy for providing insertsB and C in Figure 1 as well as Mr. Kip Carter of Educational Resources,University of Georgia, for illustrating Figures 2 and 3.

REFERENCES1. Macfadyen BV, Arregui ME, Eubanks S, et al: Laparoscopic Surgery of the

Abdomen. New York, Springer-Verlag, 2004.

2. Tams TR: Small Animal Endoscopy. St Louis, Mosby, 1999.

3. Harrison GJ: Endoscopic examination of avian gonadal tissues. Vet Med SmallAnim Clin 73:479–484, 1978.

4. Cooper JE: Endoscopy in exotic species, in Brearley MJ, Cooper JE, SullivanM (eds): Color Atlas of Small Animal Endoscopy. St Louis, Mosby, 1991, pp111–122.

5. Taylor M: Diagnostic applications of a new endoscopic system for birds. ProcEur Conf Avian Med Surg:127–131, 1993.

6. Taylor M: Endoscopic examination and biopsy techniques, in Ritchie BW,Harrison GJ, Harrison LR (eds): Avian Medicine: Principles and Appli-

ing less than 500 g using a 2.7-mm telescope and 14.5-Fr operating sheath via an oral approach. In larger birds,an ingluviotomy is required to reach the proventriculusand ventriculus. Gas insufflation can be used to dilateand examine the esophagus, crop, and proventriculus forforeign bodies. However, warm (103˚F [39.4˚C]) salineirrigation allows better visualization and superiormucosal detail and helps dilate the tract as the sheathand telescope are advanced. All birds should be intu-bated and placed at a 45˚ incline to reduce the risks ofaspiration.

Cloacoscopy using warm saline irrigation is veryrewarding and is preferred for evaluating cloacal papillo-mas as well as the coprodeum, urodeum (including theopenings to the ureters and, in females, the shell gland),bursa of Fabricius, and proctodeum. Excessive cloacalfluid administration can result in oral regurgitation, sointubation is still important (Figure 12).

CONCLUSIONThe combination of three-dimensional, real-time

color video with direct hand control and manipulationmakes endoscopy a straightforward technique to learnand, with practice, master. Initial training is bestobtained through continuing education courses andpractical laboratories. Although every opportunityshould be taken to practice these techniques on liveanimals, cadavers represent a useful but imperfectmodel because of rapid deterioration after death.

Figure 12. Gastrointestinal and cloacal endoscopy in a common pigeon.

Cloacoscopy in a common pigeon positioned in dorsalrecumbency. Note the ingress and egress fluid linesattached to the stopcocks of the operating sheath(arrows) that permit control of fluid flow for maintaining a clear endoscopy field.

Cloacoscopic view of the dorsalproctodeum illustrating the openingof the involuted bursa of Fabricius(arrow).

View of the inside of the ventriculusillustrating the yellow–green koilincovering of the mucosa and severalpieces of grit.

cation. Fort Worth, FL, Harrison Bird Diets International, 1994, pp327–354.

7. Burrows CF, Heard DJ: Endoscopy in nondomestic species, in Tams TR (ed):Small Animal Endoscopy. St Louis, Mosby, 1999, pp 297–321.

8. Pye GW, Bennett RA, Plunske R, Davidson J: Endoscopic salpingohysterec-tomy of juvenile cockatiels (Nymphicus hollandicus). J Avian Med Surg15:90–94, 2001.

9. Hernandez-Divers SJ: Endosurgical debridement and diode laser ablation oflung and air sac granulomas in psittacine birds. J Avian Med Surg16:138–145, 2002.

10. Hernandez-Divers SJ: Minimally invasive endoscopic surgery in birds. JAvian Med Surg, in press, 2004.

11. Taylor M, Murray M: Endoscopic surgery. Semin Avian Exot Pet Med 8(3),1999.

12. Chamness CJ: Endoscopic instrumentation, in Tams TR (ed): Small AnimalEndoscopy. St Louis, Mosby, 1999, pp 1–16.

13. Abou-Madi N: Avian anesthesia. Vet Clin North Am Exot Anim Pract4:147–167, 2001.

14. Paul-Murphy J, Ludders JW: Avian analgesia. Vet Clin North Am Exot AnimPract 4:35–45, 2001.

15. Hanley CS, Wilson GH, Latimer KS, Frank P, Hernandez-Divers SJ: Inter-clavicular hemangiosarcoma in a double Yellow-Headed Amazon (Amazonaochrocephala oratrix). J Avian Med Surg, submitted for publication, 2004.

16. Sturkie PD, Griminger P: Blood: Physical characteristics, formed elements,hemoglobin and coagulation, in Sturkie PD (ed): Avian Physiology. NewYork, Springer-Verlag, 1976, pp 53–75.

1. Which statement regarding avian endoscopy isincorrect?a. Birds tolerate coelioscopy better than coeliotomy.b. Coelioscopy should be performed in conscious birds.c. Coelioscopy is a minimally invasive technique.d. Rigid endoscopes are preferred over flexible endo-

scopes for most diagnostic applications.e. The cost of endoscopy is comparable with that of

radiography and ultrasonography.


ARTICLE #1 CE TESTThis article qualifies for 2 contact hours of continuingeducation credit from the Auburn University College ofVeterinary Medicine. Subscribers who wish to apply thiscredit to fulfill state relicensure requirements should consulttheir respective state authorities regarding the applicabilityof this program. To participate, fill out the test form insertedat the end of this issue. To take CE tests online and get real-time scores, log on to www.VetLearn.com.

CE

17. Hernandez-Divers SJ, Lester VK, Latimer KS, et al: Endoscopic techniquesfor the collection of lymphoid tissue from pigeons: Evaluation of splenic andbursa of Fabricius biopsy techniques and histopathologic quality. Proc AmAssoc Zoo Vet:269–270, 2003.

2. Which of the following is not a benefit ofendoscopy?a. Internal examination can be minimally invasive.b. Major surgical exposure for biopsy can be avoided.c. Biopsies can be safely performed.d. There are no risks associated with endoscopic pro-

cedures.e. Diagnosis can be expedited by facilitating lesion his-

tology and culture.

3. A rod lens telescopea. is flexible.b. is robust.c. provides better image quality than traditional endo-

scope designs.d. provides worse image quality than traditional endo-

scope designs.e. provides the same image quality as traditional endo-

scope designs.

4. When performing single-entry endoscopy inbirds, a sheath is least effective fora. preventing damage to the telescope.b. providing a means for insufflation.c. providing a means for irrigation.d. facilitating instrument use.e. preventing iatrogenic tissue trauma during entry.

5. What is the preferred method of restraint forprolonged tracheoscopy in a dyspneic bird?a. repeated intermittent use of a facemask and isofluraneb. placing an air sac tube for continuous delivery of oxy-

gen and isofluranec. connecting the anesthesia line to one of the stop-

cocks on the sheath for isoflurane deliveryd. using injectable anesthetic agentse. not using anesthesia and relying on physical restraint

alone

6. The preferred entry site for examining the avianreproductive tract is thea. left side, caudal to the last rib and ventral to the

flexor cruris medialis muscle.b. left side, caudal to the pubis and ventral to the flexor

cruris medialis muscle.c. right side, caudal to the last rib and ventral to the

flexor cruris medialis muscle.

d. right side, caudal to the pubis and ventral to theflexor cruris medialis muscle.

e. ventral midline, just caudal to the keel.

7. The liver can be visualized and a biopsy per-formed from all of the following approaches ex-cept the a. left lateral.b. right lateral.c. interclavicular.d. ventral midline.e. dorsal.

8. From which air sac can direct examination andbiopsy of the kidneys be performed?a. clavicularb. cervicalc. cranial thoracicd. caudal thoracice. abdominal

9. From which air sac are examination and biopsyof the psittacine pancreas most easy?a. left abdominalb. right abdominalc. left caudal thoracicd. right caudal thoracice. right cranial thoracic

10. From which air sac are examination and biopsyof the spleen most easy?a. left abdominalb. right abdominalc. left caudal thoracicd. right caudal thoracice. left cranial thoracic



1 ce avian diagnostic endoscopy - amazon s3 · assessing the avian reproductive tract for many...

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