avian medicine: princilpes and application

BRANSON W. RITCHIE, DVM, PhD Assistant Professor, Avian and Zoologic Medicine Department of Small Animal Medicine College of Veterinary Medicine University of Georgia Athens, Georgia

GREG J. HARRISON, DVM Director, The Bird Hospital Lake Worth, Florida President, Harrison’s Bird Diets Omaha, Nebraska

LINDA R. HARRISON, BS President, Wingers Publishing, Inc. Former Editor, Journal of the Association of Avian Veterinarians Lake Worth, Florida

AVIAN MEDICINE: PRINCIPLES AND APPLICATION

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he development of a rigid rod-lens systemand the perfection of fiberoptic cables in thelate 1950’s and early 1960’s heralded themodern age of endoscopy in human medi-

cine. A unique lens design9 allowed for improved lighttransmission in small diameter telescopes. Over thenext decade, various rigid endoscopes were intro-duced into human gynecology, orthopedics and oto-laryngology. By the middle 1970’s veterinarians wereemploying these endoscopes in animal species, andthe concept of rigid endoscopy was introduced toavian practitioners.2,27

A growing interest in aviculture, particularly of psit-tacine birds, must also be credited with stimulatingthe field of avian endoscopy. Endoscopic determina-tion of gender (surgical sexing)22 has become an int-egral part of the captive management of many avianspecies. Birds are ideal subjects for endoscopic ex-amination due to the unique design of their respira-tory system, which provides extensive pneumatiza-tion of the coelom. A variety of diagnostic uses forendoscopy in birds has previously been described;2,8,19,21

however, the greater benefits of this technology havehardly been explored. New developments in equipmentand techniques are certain to increase the value ofendoscopy to avian veterinarians.

T C H A P T E R

13ENDOSCOPIC

EXAMINATION AND BIOPSY

TECHNIQUES

Michael Taylor

Published in IVIS with the permission of the editorClose window to return to IVIS www.ivis.org

Avian Medecine : Principles and Application, B.W. Ritchie, G.J Harrison and L.R. Harrison (Eds.)

FIG 13.1 a) An artist’s impression of the lateral view of a bird showing anatomic structures of importance when endoscope is in position6 (see Figure 13.2).

1) internal carotid artery2) jugular vein3) subclavian vessels4) lung5) abdominal air sac6) eighth rib7) gonad (in this case a testicle)

8) oscoxae 9) kidney10) vas deferens11) ureter12) cloaca13) colon14) duodenum

15) pancreas16) ventriculus17) ventral hepatic peritoneal cavity18) liver19) proventriculus20) caudal thoracic air sac21) heart

22) cranial thoracic air sac23) clavicular air sac24) crop25) trachea26) pectoral muscle

SECTION TWO PATIENT EVALUATION

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b) An artist’s impression of the VD view of a bird showing anatomic structures of importance when performing endoscopy from variousentry sites: When the scope is introduced through entry site 6 (see Figure 13.2), it enters the caudal thoracic air sac. On the VD view it mayappear as though the scope goes through the abdominal air sac as well. The abdominal air sac actually forms a backwards C positioneddorsal and ventral to the caudal thoracic air sac (see Anatomy Overlay). In some species, the right and left abdominal air sacs may be moresymmetrical than shown.

1) internal carotid artery2) jugular vein3) subclavian vessels4) lung5) abdominal air sac6) eighth rib7) gonad (in this case a testicle)

8) oscoxae 9) kidney10) vas deferens11) ureter12) cloaca13) colon14) duodenum

15) pancreas16) ventriculus17) ventral hepatic peritoneal cavity18) liver19) proventriculus20) caudal thoracic air sac21) heart

22) cranial thoracic air sac23) clavicular air sac24) crop25) trachea26) pectoral muscle



FIG 13.2 Numbered endoscopic sites described for evaluation ofthe internal anatomy of birds. Entry sites are shown as eitherleft-sided approaches (open circle) or right-sided approaches(solid circle).

FIG 13.3 Left flank approach for endoscopic evaluation of the bird. The leg ispulled cranially and the entry site is at the junction of the caudal edge of the 1)eighth rib and the 2) flexor cruris medialis muscle. 3) The pubic bone serves as anadditional landmark. This approach is listed as entry site 6 in Figure 13.2.

Endoscopic laparotomy can be performed fromeither the right or left side of a bird, and 14different approaches have been described.These approaches are depicted in Figure 13.2.Site 4, located between the seventh and eighthribs, is frequently used for endoscopic evalu-ation of the gonads; however, an entrance pointthrough the left flank (site 6, Figures 13.2, 13.3)just ventral to the flexor cruris medialis muscleand caudal ventral to its intersection with thevertebral portion of the eighth rib and the pubicbone is a site that provides better visualizationof many abdominal structures.


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FIG 13.4 An artist’s rendition of the anatomic features that are visible when the endoscope is placed in different directions and at differentdepths from entry site 6 (Figure 13.2). By matching the angle and depth of the endoscope, the endoscopist can develop an insight into therelative position of organs as viewed from entry site 6. The views are divided into four angles (A,B,C,D) and depths (1 through 9). Each colorendoscopic picture has a corresponding angle and position marker to help the endoscopist envision the anatomic relationship of theendoscopic view. Thus, if the scope is oriented to B-4, the gonad, adrenal gland and kidney would be in view. Structures that will be usedfor orientation in the various endoscopic pictures include: a) lung b) ostium of the cranial thoracic air sac c) adrenal gland d) gonad e) kidneyf) ureter, oviduct, vas deferens area g) abdominal air sac h) caudal thoracic air sac i) liver j) proventriculus k) heart and l) cranial thoracicair sac.

CHAPTER 13 ENDOSCOPIC EXAMINATION AND BIOPSY TECHNIQUES

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Endoscopic Examination and Biopsy Techniques

Understanding the relationship of struc-tures is critical to effective endoscopy. Thisapproach to endoscopic anatomy will guidethe clinician through the evaluation ofthoracoabdominal structures that can beviewed from various entrance points to theabdominal cavity. (All color photographs inthis section 1994 by Michael Taylor.)

Color 13.1 The left abdominal wall has been removedfrom an Amazon parrot. Note the tieredeffect of the cranial thoracic (open arrows),caudal thoracic (arrows) and abdominal airsacs (a). The intestinal peritoneal cavity(IPC) has been infused with red dye. Otherprominent organs include the lung (lu),heart (h), liver (li) and proventriculus (p).

Color 13.2 A bird is placed in right lateral recumbencywith the leg extended cranially to show theinsertion point to entry site 6 (see Figure13.2). Dotted lines mark the caudal edge ofthe eighth rib (r), the flexor cruris medialismuscle (m) and the pubic bone (p). Theentrance site is at the junction of the eighthrib and the flexor cruris medialis muscle.

Color 13.3 Endophotograph of entry site 6 to show theeighth rib (r), ventral border of the flexorcruris medialis muscle (m) and the penetra-tion point in the lateral abdominal wall.

Color 13.4 (Position A-1 see Figure 13.4) Immediatelyafter entering the abdominal cavity of anAmazon parrot, the caudal thoracic air saccan be visualized. The air sac should betransparent with minimal vascularity. Theproventriculus (p) is ventral to the en-doscope. The medial wall of the caudal tho-racic air sac (a) becomes contiguous withthe lateral wall of the abdominal air sac.

Color 13.5 (Position A-2 see Figure 13.4) Normal cau-dal thoracic air sac of an Amazon parrot. Inthis view, a clear, unobstructed view of theostium (o) of the caudal thoracic air sacindicates that the tip of the endoscope iswithin this air space. Also visible are thedorsal edge of the left liver (li), lung (lu),proventriculus (p) and the confluent wall ofcranial thoracic and caudal thoracic air sac(open arrow). The proventricular arteriesare clearly visible (arrow).

Color 13.6 (Position A-3 see Figure 13.4) Normal or-gans and air sacs in an Amazon parrot.Ostium (o), lung (lu), proventriculus (p),liver (li), confluent wall of cranial and cau-dal thoracic air sacs (open arrow) and con-fluent wall of caudal thoracic and abdomi-nal air sacs (arrow).

Color 13.7 (Position B-4 see Figure 13.4) Maturemelanistic left testicle (t) of a Goffin’sCockatoo. Also visible are the left adrenalgland (a), ilium (i), cranial pole of the leftkidney (k), left common iliac vein (arrow)and aorta (open arrow).

Color 13.8 (Position B-4 see Figure 13.4) Normal im-mature testicle (t) of a Quaker Parakeet.Also visible are the left adrenal gland (a),right and left common iliac veins (arrows)and the caudal vena cava (open arrow).

Color 13.9 (Position B-4 see Figure 13.4) Endoscopicview of the kidney (k) and immature melan-istic ovary (o) of a six-month-old Blue andGold Macaw. Note the sulci and gyri. Ves-sels are seen through the abdominal air sacin the peritoneal membrane overlying thegonads (arrows).


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Color 13.10 (Position B-4 see Figure 13.4) Unpig-mented, mature testicle (lt) in an Amazonparrot. Also noted are the lung (lu), cranialpole of the left kidney (k), epididymis (e),right testicle (rt), caudal vena cava (arrow)and right kidney (rk).

Color 13.11(Position B-4 see Figure 13.4) Normal im-mature ovary (o) in a 14-week-old Amazonparrot. Also visible are the left adrenalgland (a), cranial pole of the left kidney (k),lung (lu), dorsal ligament of the oviduct(arrow) and common iliac vein (open ar-row).

Color 13.12 (Position B-4 see Figure 13.4) Developingovary (o), cranial pole of the left kidney (k),lung (lu), adrenal gland (a), dorsal ligamentof the oviduct (arrow) and oviduct (openarrow). The vessels coursing across the ovi-duct, kidney and ovary are present in theabdominal air sac.

Color 13.13 (Position B-5 see Figure 13.4) Normal ovaryin a 14-week-old Blue and Gold Macaw. Thenondescript, fatty-appearing ovary (o) isdifficult to identify, but the dorsal ligamentof the oviduct (arrow) coursing across thekidney (k) confirms that this is a female.The vessels coursing across the kidney andovary are in the peritoneal membrane andare seen through the abdominal air sac.

Color 13.14 (Position B-4 see Figure 13.4) Normal ovaryof a mature cockatoo. The ovary (o) ismelanistic and the developing follicles aretranslucent (arrow). The cranial pole of theleft kidney (k), lung (lu), left common iliacvein (open arrow) and aorta (a) are alsovisible.

Color 13.15 (Position B-4 see Figure 13.4) Mature ovaryof an Amazon parrot. Note the developingfollicles (f) and the characteristic yellowish(“cooked egg”) appearance of the involutedovary, indicating previous ovulation sites(open arrow). The cranial pole of the left

kidney (k) and dorsal mesentery (dm) over-lying the right kidney are also noted. Thecranial oviductal artery (arrow) is easilyvisualized. The vessels seen crossing theovary are those that are present in theperitoneal membrane and are visiblethrough the abdominal air sac.

Color 13.16 (Position C-6 see Figure 13.4) Normalepididymis (e) of an Indian Hill Mynah.Also visible are the kidney (k), caudal poleof the testicle (t) and a loop of intestines (i).

Color 13.17 (Position C-7 see Figure 13.4) Ductus def-erens (arrow) of an immature macaw. Notethat the ductus deferens is smaller than theureter (u). The kidney (k) and aorta (a) arealso visible.

Color 13.18 (Position C-8 see Figure 13.4) Ductus def-erens (d) of a mature Amazon parrot. Alsovisible are the ureter (u), kidney (k), renalportal vein (arrow), synsacrum (s), ischium(i), aorta (a) and a loop of intestines (in).

Color 13.19 (Position C-7 see Figure 13.4) Oviduct (o) ina juvenile macaw. The ureter (u), kidney(k), and vessels in the abdominal air sac arealso visible.

Color 13.20 Endoscopic appearance of chronic neph-rosis and tubular dilation in a toucan. Theabnormal kidney (k) and ureter (u) areclearly visible.

Color 13.21 (Insertion point 5 see Figure 13.2) A rightabdominal (as opposed to the normal leftabdominal) approach has been used todemonstrate the regression of the rightovary (ro) as the left ovary (lo) matures inan Orange-winged Amazon Parrot. Alsovisible are the cranial pole of the rightkidney (k), the right adrenal gland (a), thecaudal vena cava (arrow), the cranial mes-enteric artery (open arrow) and the dorsalmesentery (dm).


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Equipment

Rigid EndoscopeDiameter Size: Fine-diameter, rod-lens endoscopesare the most suitable for avian work because of theirsmall size, excellent optical resolution and superiorlight transmission capabilities. For diagnostic pur-poses, a 1.9 mm is the smallest diameter endoscopeavailable with high quality optics. This endoscope isexcellent for patients weighing less than 100 gramsor in small anatomic sites (eg, sinus, trachea, ovi-duct). The major disadvantages of these very smallendoscopes are their fragility, relatively small field ofview and transmission of less light, which limit use-fulness in larger body cavities. Because the 2.7 mmendoscope provides good light transmission capabili-ties with an adequate image size at a diameter thatmay be used in a wide range of birds, it is a good choiceas the sole or principal endoscope in an avian prac-ticea (Table 13.1).

The 2.7 mm endoscope has been used in patientsweighing from 55 grams to 4.0 kilograms. Interme-diate-sized telescopes (eg, 2.2 mm) are availableand may be preferred by some clinicians. En-doscopes (4.0 or 5.0 mm) can be employed in largerpatients or when documentation demands. The ad-vantages of the larger optics are greater lighttransmission and a bigger image circle. Most mod-ern 4.0 or 5.0 mm endoscopes also incorporate newdistal lens designs that provide a wider field ofview; these are currently unavailable in telescopesless than 4.0 mm diameter. The author has used a4.0 mm endoscope with wide-angle optics in birdsas diverse as Golden Eagles, Crowned Cranes andMarabou Storks.

Length: For general avian endoscopy, a length of theendoscope in the range of 170 to 190 mm is recom-mended. Shorter working lengths may give a morecomfortable feel in use but often lack the reach de-sired for use in the trachea, esophagus or larger bodycavities. An excessively long scope is more prone tobending or breaking.

Angle of View: The final consideration when select-ing an endoscope for avian diagnostics is the angle ofview of the distal lens element. A 0° lens offset affordsstraight ahead viewing with a natural orientation. A30° offset angles the field of view obliquely in thedirection of the offset (Figure 13.5). This allows forimproved viewing in confined areas, especially whenthe telescope is rotated. The bevelled distal lens ele-ment necessary to achieve this viewing angle enableseasier and less traumatic passage through air sac and

peritoneal walls. For these reasons endoscopes witha 30° offset are recommended for general diagnosticpurposes. Specialized telescopes (eg, 70°, 90°, 130°angles) are not useful for general avian applications.

In the late l970’s, a laparoscopic technique was de-vised using a veterinary otoscope as the optical de-vice.12 Although this instrument had the advantageof relatively low cost, it soon became clear that itcould not be compared to a rod-lens endoscope ineither optical quality or size of the incision necessary

FIG 13.5 Endoscope lens with a 30° offset allows for improvedvision in confined spaces.

TABLE 13.1 Instrumentation for Avian Endoscopy

A. Diagnostic Examination2.7 mm 30° view endoscopeGlass fiber light cableDiagnostic light source (150 W)

B. Minimum Diagnostic Working Set for Examination and BiopsyElements listed in “A” as well as:Diagnostic sheath for 2.7 mm endoscope incorporating a single5 Fr instrument channel5 Fr double spoon flexible biospy forceps (oval jaws)5 Fr flexible grasping forceps

C. Expanded CapabilitiesElements listed in“A” and “B” as well as:Diagnostic sheath incoporating a single 7 Fr instrumentchannel (for larger birds)7 Fr double spoon flexible biopsy forceps (oval jaws)5 Fr double spoon flexible biopsy forceps (round jaws)3 Fr flexible grasping forceps150 W Xenon high intensity light sourceEndovideo camera

D. Other Optics1.9 mm endoscope, many different lengths are available2.2 mm endoscope4.0 mm endoscope, 0° to 30° viewing, excellent for photo-documentation or use in larger birds


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to perform laparoscopy. In the l980’s a tubular en-doscope that attached to a handle-mount batterypack was introduced to the veterinary market as aless-expensive alternative to rod-lens endoscopes.bWhile this device had the advantages of lower cost, afocusing ocular and a length similar to a rod-lensendoscope, it had the disadvantages of poorer resolu-tion, reduced light transmission and a limited field ofview. The cost of a rod-lens endoscope system may beup to five times greater than less expensive instru-ments; however, the high optical quality, light trans-mission and field of view provide better long-termvalue when considered over the life of the endoscope.Before purchasing any endoscopic system the veteri-narian is well advised to become familiar with theoptical qualities of all systems under consideration.An endoscope must allow the clinician to examinetissues with accuracy and to recognize pathology orit is of no value. High quality optical systems arerequired to enable the clinician to achieve reliable,reproducible results. With appropriate care, modernrigid endoscopes should have a working life of five toten years.

Veterinarians who see so few cases that they cannotjustify the purchase of the appropriate equipmentshould refer endoscopy services to more experiencedpractitioners. Over the past decade, rod-lens en-doscopes have become the standard for use in avianendoscopy.2,8,21,23,27 The interests of clients and pa-tients are best served by the use of quality opticalequipment.

Flexible Endoscopes

Conventional flexible endoscopes are based entirelyon fiberoptic systems for both illumination and imag-ing. Unlike modern rigid endoscopes, which employsolid rod-lenses, flexible endoscopes use many coher-ent, flexible, glass fiber bundles to transmit the im-age.10 Rigid telescopes, particularly those with asmall diameter, offer far better image resolution,illumination and quality than is technically possibleto achieve with a flexible system. However, flexibleendoscopes do provide a controllable distal tip, whichallows manipulation that is not possible with a rigidrod-lens endoscope. They are most useful in examin-ing tubular organs that are sinuous or folded. A l0mm flexible colonoscope was found to be effective inremoving lead shot from the proventriculus of Trum-peter Swans.3 Fine-diameter, flexible endoscopesmay have limited usefulness in smaller birds (eg, lessthan 800 g body weight) when compared to newerrigid systems.

The major disadvantage of a small-sized, flexibleendoscope is that one cannot control the tip directionunless the instrument is located in a confined areasuch as the gastrointestinal tract. In an open area(such as the air sac), the scope cannot be manipu-lated or used to penetrate beyond the air sac wallswithout a probe. A specialty avian practice may havea small diameter flexible endoscope available to per-form indicated procedures. Large flexible scopes withan operating channel for placement of grasping andbiopsy instrumentation can be used in ratites.

Instrument Care

Flexible and rigid endoscopes are expensive, preci-sion, optical instruments that will give excellentlong-term performance if properly maintained. Rigidtelescopes, especially those of small diameter, arefragile and must be carefully handled during trans-port and cleaning to avoid damage to the rod-lenselements. Torsional stresses upon the long axis of theendoscope must be avoided. This is most importantwhen a fine-diameter telescope is being used withouta protective sheath, as is frequently the case fordiagnostic purposes. It is particularly important thatthe operator be sensitive to the amount of force beingapplied to the telescope during a procedure. Rigidendoscopes should always be picked up by the ocular(eyepiece) rather than the distal tip. One should laythe instrument flat to avoid bending the optical tipand fracturing the optic bundles. It is wise to cleanthe instrument immediately after a procedure is fin-ished. A nonabrasive cleanser may be used to removefat and debris. In many cases, simply washing thetelescope in distilled water is all that is needed. Aquality lens paper is used to clean the lens surfaces.An alcohol flush chemically dries the endoscope be-fore it is placed in a padded storage container that

CLINICAL APPLICATIONSRigid endoscopes should always be picked up by theocular (eyepiece) rather than the distal tip.

For office or field sterilization, sensitive endoscopic equip-ment may be soaked in a two percent solution of glutaral-dehyde (of a type approved by the manufacturer of theequipment).

Moderate to marked obesity leading to the intra-abdominaldeposition of fat is the most frequent cause of difficulty inendoscopic visualization.

Familiarity with anatomy, use of gentle tissue handlingtechniques and careful movements of the endoscope willreduce the risk of iatrogenic trauma.


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meets the manufacturer’s recommendations. A sim-ple but effective plastic endoscope sleeve is availableto cover the shaft of the telescope for protection dur-ing transport and disinfection procedures (Figure13.6).

Flexible endoscopes should also be handled withcare. They should not be coiled tightly or have objectsof any weight placed on the shaft, or the glass fiberbundles will be damaged. Instrument channelsshould be flushed thoroughly with warm soapy waterto remove debris after use. Most manufacturers rec-ommend that flexible endoscopes be stored sus-pended from the ocular end with the flexible shaftallowed to hang vertically. Detailed instructions forendoscope care are provided by most manufacturers.Technical staff should be properly trained in thehandling and cleaning of these sensitive instrumentsbefore receiving the responsibility for their care.

SterilizationMost endoscopic procedures require properly steril-ized equipment. Even in the examination of noncriti-cal areas such as the oral cavity or ear canal, it isprudent to remember that many animals (particu-larly carnivores) may harbor pathogenic organismsthat can be physically transferred to another patient(particularly birds) if instrumentation is not disin-fected between examinations. Due to the sensitivityof the rod-lens systems, sterilization by autoclavingis seldom recommended by the manufacturer. Expan-sion and contraction caused by the marked tempera-ture extremes of steam autoclaving will damage orseverely shorten the life of most telescopes. Sometypes of recently produced rigid endoscopes aresteam autoclavable, although this process may alsodecrease their working life.

Two options provide safe yet consistently reliablesterilization for sensitive telescopes and light cables.Ethylene oxide gas is an extremely effective ster-ilant, but exposed materials must be aerated for aminimum of eight to twelve hours before use. Ethyl-ene oxide is a human health hazard and must be usedunder carefully controlled conditions.

The most practical and safe alternative for the avianpractitioner for office or field sterilization of sensitiveendoscopic equipment is soaking in a two percentsolution of glutaraldehyde (of a type approved by themanufacturer of your equipment).c The solution mustbe used according to the supplier’s directions forsoaking telescopes, hand instruments and light ca-bles. The practitioner should be aware of the acti-vated life of the product (usually 14 to 28 days) andchange solutions accordingly. Stacking or layeringinstruments in the soak tray should be avoided sothat the solution can properly reach all surfaces.Circulating the solution using a syringe is useful toensure that all surfaces have been contacted. Mini-mum recommended soaking times in properly pre-pared glutaraldehyde solutions typically range from15 to 20 minutes. Although greater germicidal effectis achieved the longer the equipment is soaked, manymanufacturers caution against soaking for longerthan two hours, as damage to glass fibers may occur.

After the soaking cycle has been completed, theequipment must be thoroughly rinsed in sterilewater to prevent tissue-damaging glutaraldehydefrom contacting the patient. Glutaraldehyde is ex-tremely irritating to most tissues and may causelocal irritation, tissue death, delayed healing andperitoneal reaction. Rinsing the equipment in a ster-ile container of sterile water for three to five minutesis most effective. The instruments are drained, im-mersed in a second container of sterile water forthree to five minutes and wiped dry. A final alcoholwash may be used to chemically dry the equipment.

Other types of disinfectant solutions such as quater-nary ammonium compounds, chlorhexidine and povi-done iodine are not acceptable alternatives to two percent glutaraldehyde solutions for soaking endoscopicequipment. With the number of resistant viruses andbacteria seen in many avian species, it is importantfor the endoscopist to ensure that only effective, ap-proved products are used, or the result may be theunnecessary spread of disease.

FIG 13.6 A sleeve should be placed over the endoscope for protec-tion during movement or sterilization.


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Clinical Applicationsof Endoscopy

Pre-endoscopy Considerations

IndicationsEndoscopic examination is indicated whenever thevisual inspection of an organ or site may yield addi-tional diagnostic information. Diagnostic endoscopyis usually preceded by less-invasive examinationssuch as a complete blood count, biochemistries orradiology. The patient’s history, findings of the physi-cal examination and the results of laboratory andradiologic studies may not be conclusive or may sug-gest endoscopic followup for additional diagnosticinformation (Table 13.2).

TABLE 13.2 Common Indications for Endoscopic Examination

Loss or change in character of voice

Acute or chronic dyspnea

Acute or chronic sneezing

Ingluvitis, crop burns or trauma

Abnormal radiographic findings (plain or contrast); eg, lung,gastrointestinal tract, air sacs, organomegaly, granuloma

Abnormal biochemical studies; eg, kidney (uricemia) or liver(elevated bile acids or liver enzyme activities)

Persistent leukocytosis (nonresponsive to treatment)

Acute or chronic systemic disease

Reproductive system (suspected infertility)

Polyuria, polydipsia

Follow-up examination to check on lesion resolution (“second look”)

Diagnostic Uses: The endoscope and its light cablemay be used to aid the physical examination.8 Thelight cable may be used singly to offer additionalillumination, to transilluminate a structure such asthe trachea, sinus or crop, to augment examinationof the oral cavity or for back lighting of overexposedradiographs. Fine-diameter endoscopes can be usedin a variety of external sites where the properties ofmagnification, illumination and small optic diameterenhance diagnostic visualization. Many structures ofthe eye, ear canal, nares, oral cavity and upper res-piratory tract may be examined without anesthesia.More thorough, noninvasive examinations of otherbody orifices are best completed under general anes-thesia. The high quality optics of modern endoscopesallow visualization and inspection of tissues undermagnification and are particularly useful in confined

areas. Fine-diameter endoscopes introduced througha small incision, often referred to as laparoscopy,2permit excellent visualization of the coelomic cavitiesand air sacs, while creating minimal trauma.

Endoscopy has been compared to performing a ne-cropsy on a live bird.21 The endoscopist must becomefamiliar with the normal and pathologic appearanceof the tissues to be examined. Lesions should bedescribed accurately regarding the location, color,size, shape and consistency. Photo or video documen-tation can be a tremendous aid in this process. In onestudy, the ability to review video recordings of exami-nations was believed to be an essential tool in under-standing certain anatomic relationships in juvenilemacaws.29

Improved instrumentation enhances the routine col-lection of specimens of suspect or abnormal-appear-ing tissue and debris for histologic, cytologic andmicrobiologic examination. Previous techniques forbiopsy and specimen collection have relied on themanipulation of secondary instrumentation (eg, rigidbiopsy forceps or cannulas for micro-swabs) separatefrom but in coordination with the endoscope. Thesetechniques are awkward and can lead to iatrogenictrauma.18,19,20 A new diagnostic endoscopy system forbirds has recently been developed that greatly sim-plifies sample collection.11,31 The system incorporatesa 2.7 mm, 30° view endoscope with a single instru-ment port in a special sheath (Figure 13.7). Variousflexible instruments may be introduced into thesheath, passed alongside the endoscope and guidedto a specific site with great ease (Figure 13.8). Iatro-genic tissue trauma is markedly reduced because theinstruments are directed to the visual field throughthe integral sheath, avoiding the blind manipulationrequired to place a second, rigid instrument.

Surgery: Harrison8 first suggested the use of theendoscope as an operating telescope in open aviansurgery to enhance visualization of small structures.

Endoscopic surgery is currently one of the fastestgrowing areas in the human surgical specialties. Spe-cial hand instruments have been developed to enabletissue manipulation, suture and clip placement andradiosurgical techniques using the endoscope. Theadvantage of this type of surgery in humans hasdecreased patient trauma and hospitalization. Thetechnology offers great promise if it can be adaptedfor avian surgery. In addition to decreased trauma,the magnification and illumination provided by aquality endoscopic system enable more precise tech-niques in small avian patients. Surgical procedures


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are under development for endoscope-guided hyster-ectomy, ulcer repair and egg removal.

Identification of Gender of Monomorphic Birds:The use of endoscopy to identify the gender of mono-morphic birds was the earliest widespread applica-tion of this technology in avian medicine; it has beenthe major force supporting the development and in-troduction of improved diagnostic capabilities utiliz-ing endoscopy.

ContraindicationsThe general contraindications for endoscopy arethose that would apply to general avian surgery andanesthesia. Moderate-to-marked obesity leading tothe intra-abdominal deposition of fat is the mostfrequent cause of difficulty in endoscopic visualiza-tion. Large peritoneal fat reserves may make theexamination of parts of the coelom impossible. Insome cases, an improved diet is recommended for thepatient (with reexamination in six to eight weeks).

The presence of ascites may cause difficulties if theperitoneum of the ventral hepatic peritoneal cavity(VHPC) or intestinal peritoneal cavity (IPC) isbreached while entering the air sac. Fluid could drainfrom the peritoneal cavity into the air sac and fromthere into the lung, leading to aspiration and death.This is most likely to happen in a lateral approach tothe caudal thoracic air sac. If ascites is suspected andan endoscopic examination of the liver is necessary,the ventral approach to the VHPC should be used.

Fluid from the VHPC will drain fromthe incision site and can be safelysuctioned without the concern for airsac involvement.

Left coelomic examinations shouldnot be performed in the hen near thetime of ovulation, as the ova greatlyenlarges in size, virtually obliterat-ing the abdominal air sac. The ovi-duct also increases in size and tortu-osity, filling the left portion of theIPC. Use of the post-pubic approachto the abdominal air sac risks dam-age to the oviduct or an egg nearingoviposition. A left lateral coelomic ap-proach is rendered less useful by thepresence of large, developing ovathat makes visualization difficult.Attempting passage into the abdomi-nal air sac from the caudal thoracicair sac may be difficult and poten-

tially risks damage to the ova.

Inexperience of the operator remains one of the mostcommon causes of endoscopic complications.8,21 Vet-erinarians considering the addition of endoscopicservices to their avian practice are well advised toseek out appropriate continuing education and tobecome thoroughly familiar with normal avian anat-omy. Experienced colleagues may be contacted foradvice on practical equipment needs before purchas-ing new equipment. Necropsy specimens can be usedto study endoscopic principles and are particularlyuseful in learning to identify tissue changes. Lec-tures and laboratories are available on endoscopictechniques.

FIG 13.7 A specialized 2.7 mm endoscope that fits into a sleeve is ideal for most avianendoscopic procedures. The sleeve has been designed to accomodate the introduction ofbiopsy forceps and other flexible instruments to facilitate the collection of diagnosticsamples (courtesy of Karl Storz Veterinary Endoscopy–America).

FIG 13.8 Biopsy forceps passing through a specially designedsheath for a 2.7 mm endoscope (courtesy of Karl Storz VeterinaryEndoscopy–America).


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ComplicationsAs part of the informed consent process, the clientmust be made aware of potential complications of theendoscopic process. Anesthesia-related incidents aredescribed in Chapter 39. Organ trauma is one of themost serious intraoperative endoscopic complica-tions. The proventriculus may be punctured using atrocar and cannula or similar entry device from alateral approach. Failure to identify and repair thisinjury can result in a fatal peritonitis. Laceration ofa blood vessel or organ such as the liver or spleen ispossible and may lead to serious or fatal hemorrhage.Liver or kidney contusions can be caused by theendoscope tip during excessively vigorous manipula-tion. These are infrequently the cause of seriousclinical problems.

Familiarity with anatomy, use of gentle tissue han-dling techniques and careful movements of the en-doscope will reduce the risk of iatrogenic trauma.

Subcutaneous emphysema is a potential (if rare)postoperative complication. Air may leak through thebody wall at the point of the air sac entry and collectunder the skin. Usually, the body wall opening willseal without incident, but occasionally the skin inci-sion must be reopened and the body wall puncturesutured. This is most common when a large en-doscope or sheath has been used. Endoscopic punc-tures may be routinely closed with a fine-diameter,absorbable, monofilament suture.

Air sac and peritoneal granulomas can occur by usinginstrumentation that has been improperly sterilizedor in situations where poor technique or inadequateskin preparation has allowed contamination of theendoscope tip. The peritoneum of most birds seemsto be quite forgiving of small insults. Many granu-lomas may not be appreciated clinically. The authorand editors have never experienced a case of gener-alized sepsis related to endoscopic manipulation, al-though this may be possible in cases where the wallof an existing granuloma is damaged or where inef-fective sterilization practices have been used. Colddisinfectant solutions such as chlorhexidine2 are notappropriate, as some organisms such as Pseudo-monas aeruginosa will survive this treatment. Nocomprehensive studies have examined the endoscopyand biopsy sites days to weeks following the proce-dure. However, preliminary work indicates thatthere was no local infection in patients where a twopercent glutaraldehyde solution was used for instru-ment preparation and appropriate sterile techniquewas employed. The inability to perform proper ster-

ilization of a single endoscope makes surgical sexingclinics obsolete. Transmission of viral infections (par-ticularly Pacheco’s disease virus and polyomavirus),resulting in the loss of numerous birds has beenlinked to “sexing clinics.” The mixing of birds frommultiple sources (particularly when an invasive pro-cedure is performed) should be discouraged. It ispossible, however, to safely perform endoscopy onseveral birds from a single client by utilizing twoendoscopes, with one being sterilized while the otheris in use.

Patient PreparationPatients should be fasted a minimum of three hours.In some cases the length of the fast is extended,especially if the endoscopic examination will involvethe gastrointestinal tract. Species that consumelarge boluses of whole foods (eg, raptors) may requirefasting for 24 to 36 hours. Failure to do this maymake examination of many portions of the coelomimpossible due to distension of the proventriculus.

Surgical sites are prepared as for any avian surgery.Particular attention should be paid to the skin sur-face. The endoscope can transmit surface debris intothe body cavity if the entry site is not properly pre-pared. Small, sterile, transparent, wound dressingsd

make excellent drapes for endoscopic procedures.They are available in a variety of sizes and are lightlyadhesive so they stay in place without clamps; theirtransparency improves anesthetic monitoring insmall patients.

Anesthesia: Appropriate anesthesia is an essentialpart of good endoscopic practice. It is seldom possibleto perform an endoscopic examination in the physi-cally restrained bird without the risk of organ contu-sion or other trauma. Consistency in positioning ofthe patient is mandatory for anatomic orientation.Maintaining position is neither possible nor humaneusing physical restraint only. Clinical anesthesia hasbeen thoroughly reviewed in Chapter 39. The anes-thetic agent of choice for most endoscopic proceduresremains isoflurane.e

Sites of Application

Air Sacs, LungsBirds are excellent subjects for endoscopic examina-tion because the unique system of air sacs allowsvisualization of coelomic structures without artificialinsufflation. Air sacs invaginate the thoracoabdomenof birds to facilitate examination of or access to spe-cific organs. There are marked similarities in the


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morphology of caudal air sacs among selected Pas-seriformes, Psittaciformes, Columbiformes, Gruifor-mes, Strigiformes and Falconiformes. In chickens,there are three paired air sacs (cranial thoracic, cau-dal thoracic, abdominal) and two single, median airsacs (cervical, clavicular).17

There is one published examination of air sac mor-phology in a psittacine bird (budgerigar).4 The budg-erigar has paired, unfused cervical air sacs but wasotherwise similar to the chicken. The caudal thoracicair sacs of the pigeon extend farther caudally than inmost Psittaciformes. In some diving birds, the caudalthoracic air sacs are much larger than in other spe-cies. This is assumed to be an adaption to increasedair requirements while diving underwater.

For endoscopic purposes, it is preferable to considerthe cranial and caudal thoracic and the abdominalair sac pairs together. In the parrot, the cranial tho-racic air sacs are the smallest of the group and arelocated ventral and cranial to the caudal thoracic airsacs (Color 13.1). They are best accessed from theventrolateral thoracic wall using the approach firstdescribed by Bush,2 who suggested an entry sitecaudal to the last sternal rib in the area of the lateralnotch (a “V”-shaped depression palpable between thesternum and the last rib).

The patient is placed in lateral recumbency with thewings extended dorsally. The wings may be taped toa restraint surface or they may be affixed with ashort loop of non-adhesive, self-adhering tapef

passed between the primary feathers and around thecarpus. The landmarks are located and a small skinincision is made. The musculature of the body wall isbluntly separated and the endoscope is inserted in acraniodorsal direction. From this approach the peri-cardial sac and heart can be seen as well as the lobeof the liver and the caudal, ventromedial surface ofthe lung (Color 13.23).

The traditional left lateral surgical approach takesadvantage of the air sac anatomy to approach thegonads by either directly entering the abdominal airsac or by entering the caudal thoracic air sac first andthen passing into the abdominal air sac through asmall incision (see Figure 13.2). This approach issimilar to the early laparotomy techniques of fieldornithologists.1,26

The patient is placed in true lateral recumbency withthe wings extended dorsally. The upper leg is ex-tended and held caudally. The point of insertion islocated by palpating the triangle cranial to the mus-

cle mass of the femur, ventral to the synsacrum andcaudal to the last rib.8,19,23 The body wall may bepenetrated by a trocar and cannula or by blunt sepa-ration. In Psittaciformes, this entry site has beendemonstrated to occur between the seventh andeighth ribs (not the behind the last rib). With thisapproach, the tip of the endoscope enters the mid tocaudal portion of the caudal thoracic air sac in mostbirds.

As an alternative approach to the caudal thoracic airsac, the bird is restrained in lateral recumbencyexcept that the leg is extended cranially.15 The site ofentry is the same as previously described in theupper part of the triangle formed by the proximalfemur, the last rib and the cranial edge of the pubis.

A similar approach to the caudal thoracic air sacsthat is based upon precise landmarks has been devel-oped (see Figure 13.3).29,30,31 The animal is positionedas described. The entry site is located by finding thepoint where the semimembranosus muscle (M. flexorcruris medialis) crosses the last rib (Color 13.2). Theventral fascia of the semimembranosus muscle isbluntly separated from the underlying body wall andthe muscle is reflected dorsally. A blunt entry is madejust caudal to the last rib, beneath the reflectedsemimembranosus muscle. Except in individualswith moderately to markedly increased fat reserves,the landmarks are located easily. The procedure isreproducible in members from a wide variety of or-ders including Psittaciformes, Passeriformes, Co-lumbiformes, Gruiformes, Falconiformes and Strigi-formes. A major advantage in placing the leg forwardis that the lateral body wall can be more easilyapproached without the interference of the femoralmusculature. This becomes particularly important inbirds with heavily muscled upper thighs (eg, manyPsittaciformes).

With either of these approaches the endoscope entersthe caudal thoracic air sac at or near its caudalborder. Color 13.4 was photographed from the leftentry point of this caudal approach looking cranially.Visible from eleven to one o’clock is the caudal sur-face of the lung with its large ostium. From the twoto three o’clock position is the transparent membraneformed by the confluent walls of the caudal thoracicair sac and the abdominal air sac. Passing throughthis wall would place the endoscope within the ab-dominal air sac. At four to six o’clock is the ventrolat-eral border of the proventriculus. The lateral edge ofthe left lobe of the liver may be seen at the seven toeight o’clock position. From nine to ten o’clock is


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another transparent membrane. This one is com-posed of the walls of the confluent caudal thoracic airsac and cranial thoracic air sacs. Passing throughthis membrane would place the tip of the endoscopein the cranial thoracic air sac.

The abdominal air sacs of most birds are the largestair sacs. They extend from the caudal surface of thelung to the craniolateral borders of the cloaca. Entryinto the abdominal air sacs may be gained throughone of the previously described caudal thoracic airsac approaches or by direct access through the caudalbody wall. Lumeij21 was the first to describe a post-pubic approach to the caudal portion of the abdomi-nal air sac. The entry point is situated dorsal to thepubic bone and caudal to the ischium (see Figure13.2). The endoscope generally first enters the mostcaudal portion of the intestinal peritoneal cavity andmust be penetrated through this thin membrane toenter the abdominal air sac. The endoscope can thenbe moved cranially up the length of the abdominal airsac. From the left approach a large number of struc-tures may be examined including the kidney, adre-nal, gonad and associated structures, spleen, proven-triculus, ventriculus and intestine (Color 13.26). Theabdominal air sac may also be approached from aflank position. The entry site is located directly ven-tral to the acetabulum and just dorsal to the ventralborder of the flexor cruris medialis muscle.

Reproductive OrgansIn most avian species, only the left ovary and oviductdevelop.14,16 The development of the right ovary isnormally arrested in a testis-like stage and can fre-quently be visualized near the right adrenal gland,along the caudal vena cava (Color 13.8). For thisreason, endoscopy to examine gonadal structures isperformed through the left side of the abdomen.

The testicle of the adult male bird is ellipsoidal tobean-shaped. In most species it is creamy white al-though it may be more or less pigmented (gray toblack) in others (eg, cockatoos, mynahs, toucans)(Color 13.7). Under the seasonal influence of hor-mones, the mass of the testicle may increase from 10up to 500 times.14 The pattern of surface vesselsincreases and becomes more prominent. Theepididymis enlarges, and the ductus deferens be-comes very tortuous in preparation for storage andtransportation of the spermatozoa (Color 13.16).

In contrast, the ovary of the mature female has theappearance of tapioca pudding with many small fol-licles visible during the nonbreeding season. Under

appropriate hormonal stimulation, a hierarchy offollicles develops and matures giving the ovary theappearance of a cluster of grapes (Color 13.15). Afollicle enlarges as it matures; simultaneously, theoviduct increases in size and becomes tortuous andfolded in preparation to accept the ovum. A largeovum can be mistaken for a testicle, especially in anobese bird where other structures are difficult to seeor where the surgeon fails to check related anatomicreference points.

The differences in the morphology of adult gonadsare relatively distinct. In juvenile birds, gonadal tis-sue is less obvious and differentiation is more diffi-cult. It is possible to endoscopically identify the cor-rect gender of most species of birds at a young age ifgood optical equipment is used and a careful exami-nation of the gonads and associated structures isperformed.

In one study of juvenile macaws,29 differentiation ofthe sexes was uniformly possible as young as sixweeks of age when gonadal and oviductal or ductusdeferens morphology were considered together. Tes-ticles were tubular to ellipsoidal with distinct,rounded cranial and caudal poles. A paired righttesticle could usually be seen through the dorsalmesentery (Color 13.10). The ductus deferens was athin, white tubular structure, usually only one-thirdthe diameter of the ureter (Color 13.17).

The juvenile ovary was comma-shaped, dorsoven-trally flattened and closely applied to the adrenaland cranial pole of the kidney. The surface texture ofthe ovary was dependent on the age of the bird. Veryyoung ovaries had a faintly granular surface withfine sulci (Color 13.13). As the birds aged, the sulcideepened, giving the ovary a furrowed, brain-likeappearance (Color 13.12). With the maturation of theprimary oocytes, the ovary began to take on a dis-tinctly granular texture with a more three-dimen-sional shape, and the sulci disappeared (Color 13.14).The oviduct was pale white with a thicker, moresubstantial appearance than the vas deferens. Theoviduct was generally two to four times the thicknessof the ureter and on close inspection, fine, longitudi-nal, spiral bands were visible (Color 13.19). Thesemay have represented the developing spiral folds ofthe mature oviductal mucosa. The most interestingfinding of this study was the presence of the support-ing ligament of the infundibulum, which was clearlyvisible crossing the cranial division of the kidney.This structure is part of the dorsal ligament of theoviduct and is absent in juvenile males (Color 13.11).


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From this approach, it may be difficult or impossibleto view the right side in mature birds. Examinationof the right abdominal air sac (AAS) would be re-quired to confirm the presence of abnormalities re-lated to the remnant ovary or the right testicle suchas ovotestes or hermaphrodism. While these condi-tions are uncommon, their presence may need to beruled out in cases of infertility.

Caution should be exercised in estimating age, repro-ductive history or reproductive potential based upona single endoscopic examination. During the non-breeding times of the year, the adult gonads return toa quiescent state similar to those of the late adoles-cent bird. Several male Hyacinth Macaws in theirteens had very small testicles, yet went on to breedwithin months of evaluation. A mature African GreyParrot showed no evidence of follicular developmentat examination but ovulated 24 days later.

During the endoscopic examination for gender deter-mination, the endoscopist is able to evaluate the airsacs, liver, lung, spleen, kidney, adrenal gland, pro-ventriculus, ventriculus and the visual portions ofthe intestines. A systematic examination that maysuggest a subclinical health problem can providedata of value to the aviculturist. This information isnot available using cytogenetic or molecular biologi-cal techniques of gender determination.

Ear CanalThe external auditory meatus is hidden by special-ized covert feathers that lack barbules. There is nopinna. The opening is usually rounded but can varyin diameter from small (2.0 to 15.0 mm in passerineand psittacine birds) to very large (up to 6.0 cm inowls). The ear canal is straight and short. The tym-panum can usually be visualized clearly (Color13.41). A 1.9 mm telescope is often needed to explorethe deeper aspects of the canal. Unlike the dog andcat, birds infrequently suffer from otitis externa.

OropharynxThe oral cavity is easily approached in most avianspecies. The bill may be held open manually or witha speculum. In species with strong mandibular mus-culature (such as Psittaciformes) it is recommendedthat the patient be anesthetized for most oral exami-nations. If manual restraint is used, extra care mustbe taken to prevent damage to the equipment.

The avian tongue may exhibit a number of adapta-tions for food prehension and manipulation. In manyspecies it is a flat, triangular-shaped organ with a

relatively smooth epithelium. Psittaciformes havelarge, fleshy tongues ideally suited to food manipula-tion. They are the only order with intrinsic lingualmuscles17 that allow a great variety of movement andflexibility. In many species, including parrots (Color13.34), there are a group of mucus-secreting salivaryglands at the base of the tongue. Inspissation ofkeratinized debris due to squamous metaplasia willbe seen in birds suffering from hypovitaminosis A(Color 13.33).

Salivary glands are most prominent in species thateat primarily a dry diet (cereal grains) and may beabsent in those that eat a moist, lubricated diet(fish). In the parrot, salivary glands are found alongthe roof and the floor of the mouth and on the tongue.The oropharynx is lined with stratified squamousepithelium and may be keratinized in areas of wear.In some species, the epithelium may be heavily pig-mented. It normally has a smooth, unblemished sur-face except in areas where spike-like sensory papillaeare present (Color 13.34). The mucosa should beexamined for adherent exudate, debris or ulcers, asmay be seen in certain protozoal (eg, Trichomonassp.), fungal (eg, Candida albicans) or viral (eg,poxvirus) diseases.

The choanal slit is visible as a median “V”-shapedcleft in the palate. There is species variation in thewidth of the choanal borders. In pigeons and mostraptors, the choana is slit-shaped (Color 13.35). Inthe parrot the borders are more widely spaced, form-ing a distinctive “V” shape. The borders of the cho-anal slit are lined with sensory papillae. By enteringthe choanal slit with the scope and moving craniodor-sally, the nasal septum and conchae can be examined(Color 13.37). Just caudal to and on the midline of thechoana is the small slit-like infundibular cleft. Thisis the common opening of the right and left pharyn-gotympanic tubes17 also referred to as the eustachiantubes (Color 13.35).

The laryngeal mound is visualized at the base of thetongue on the midline of the caudal floor of the oro-pharynx. The paired, fleshy laryngeal prominencesopen and close to form the conspicuous glottis. Thereis no epiglottis (Color 13.31).

TracheaThe trachea may be entered at the larynx by passingthrough the glottis of an anesthetized patient. Theavian larynx does not contain vocal cords. Trachealrings of the bird are usually calcified and are com-pletely circular. The tracheal mucosa consists of


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smooth, stratified squamous epithelium. The syrinxis the site of sound production and is located wherethe trachea bifurcates into the primary bronchi. Thesyringeal membrane may be the site of opportunisticbacterial and fungal infection (aspergillosis).25 Tra-cheoscopy to the level of the syrinx is possible inmedium-to-large birds using a 180 mm long, 2.7 mmendoscope. Smaller patients (larger than cockatiels)may be examined with a l.9 mm endoscope. Visuali-zation can be improved by extending the neck. Inpatients with acute to subacute dyspnea, tracheo-scopy should be considered to rule out foreign objectsor inflammatory debris.

In seed-eating birds, hulls or whole seeds may beaspirated into the larynx or syrinx. In carnivorousbirds, small pieces of bone, tendon or cartilage maybecome lodged in the glottis. These may be removedusing endoscopically guided grasping forceps. Tra-cheitis may be caused by bacterial or viral agents.Culture of the endoscope tip immediately after re-moval from the patient may be helpful in determin-ing an etiologic agent.

Esophagus and IngluviesThe esophagus is easily entered by passing the en-doscope caudally into the pharynx and over the la-ryngeal mound. The surface of the esophagus is com-prised of longitudinal folds that vary depending uponthe dietary habits of the species (see Color 19). Forexample, the number and size of folds and the degreeof distensibility are less in insectivores and seedeaters than in carnivores like hawks and owls (Color13.38).

It is a common misconception that all birds have aningluvies. Galliformes, Psittaciformes, Columbifor-mes and some Passeriformes have a true crop. Theingluvies can be examined with either a flexible orrigid endoscope after passing the instrumentthrough the cervical portion of the esophagus. Insuf-flating the crop with air will help with visualization.To do this, a small-diameter, flexible feeding tube,gwhich has been attached to a 35 or 60 cc syringe, canbe passed into the crop (Color 13.39). Alternately, theinsufflation channel on a 4 mm or greater diameterflexible endoscope, or the instrument channel on theStorz rigid avian sheatha can be used to distend theingluvies with air. Some pressure will need to bemaintained around the proximal cervical esophagusto retain the infused air within the crop. Patientsundergoing elective ingluvioscopy should be fastedfor several hours before the procedure to reduce theeffects of retained food materials upon visualization.

With this technique the crop mucosa can be thor-oughly examined and small foreign objects can beremoved with grasping forceps. The grasping forcepscan be endoscopically guided using either a flexibleendoscope with an instrument channel or the rigidsheath with channel.

Proventriculus, VentriculusThe proventriculus and the ventriculus may be ex-amined using either flexible or rigid equipment. In a250 to 600 g parrot it can be a difficult chore to guidea small-diameter, flexible endoscope down the cervi-cal esophagus, across the crop and into the thoracicesophagus, although this equipment can be usedsuccessfully in larger parrots and in moderatelylarge avian species that lack a crop (eg, owls andAnseriformes). A pediatric bronchoscope is requiredin smaller patients. The smallest practical flexibleendoscopes with an instrument channel are pediatricbronchoscopes at 4.0 mm and 5.0 mm diameter. Hu-man flexible colonoscopes (10.0 mm) have beenshown to be useful in very large species such asswans and cranes.3 Once the endoscope is positionedin the thoracic esophagus, the pathway becomes arelatively straight one continuing into the proven-triculus (Color 13.40) and the ventriculus.

Preliminary studies using a midline ingluviotomy toenter the thoracic esophagus using the Storz 2.7 mmrigid endoscope and instrumented sheath have beenperformed.a Birds were anesthetized, intubated andplaced in dorsal recumbency.

Care was taken to avoid the passage of proventricu-lar contents into the trachea or choana by insertingan absorptive gauze tampon into the cranial cervicalesophagus and ensuring that the endotracheal tubewas secure. Whenever possible, patients were fastedfor five to six hours in order to empty the proventricu-lus. In cases where fasting was not possible (eg, acuteforeign body ingestion), the proventriculus wasflushed with sterile saline and ingesta was forcedout of the thoracic esophagus and into the crop, fromwhich it was suctioned. Placing the patient with itshead down facilitated this procedure. A small skinincision was made over the middorsal portion of thecrop. The crop wall was incised. The entrance to thethoracic esophagus was located on the ventralmidline border of the crop, and the telescope andsheath were introduced.

The sheath and endoscope were inserted into thethoracic esophagus. A 3-5 Fr rubber catheter con-nected to a syringe containing saline was inserted


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into the instrument channel for use in flushing de-bris from the visual field. Grasping forcepsj (3 Fr or 5Fr) can be inserted into the channel to manipulateand remove foreign objects. The crop incision wasclosed using standard techniques.

Ventral Hepatic Peritoneal CavitiesThe liver of the bird is encapsulated within twopaired peritoneal cavities: the ventral and dorsalhepatic peritoneal cavities. The paired ventral he-patic peritoneal cavities (VHPC) are the largest andof greatest clinical significance. The right and leftVHPC are separated by the ventral mesentery. Theright lobe of the liver is larger in most birds (Colors13.22, 13.28).

To gain access to the liver, one or both of these ventralcavities must be entered. The liver can be visualizedfrom the cranial and caudal thoracic air sacs (Colors13.5, 13.24) and indeed seems tantalizingly close inmost birds. In reality, the liver is covered by a layerof peritoneum that is contiguous with the overlyingair sac. To access the liver, the ventral hepatic perito-neal cavity (VHPC) must be entered either laterallyfrom the caudal thoracic air sac or by a direct, ventralmidline approach. The ventral approach16 is best forexamining and sampling both lobes of the liver. Askin incision is made on the midline just caudal to theborder of the sternum. The linea alba is incised andthe caudal border of the VHPC is bluntly penetrated.A substantial fat pad may be present overlying theouter surface of the caudal border of the VHPC.Under conditions of health, the liver should not pro-trude past the caudal border of the sternum.

The VHPC may also be entered from the caudalthoracic air sac. This may be most convenient whena lateral approach has been used for a general diag-nostic examination and liver lesions have been noted.An opening can be made in the confluent walls of thecaudal thoracic air sac and the VHPC by using endo-scopically guided forceps to pick up and tear a smallhole in the membranes. The lateral border of the livercan then be grasped through this VHPC access (Col-ors 13.29, 13.42). This approach is contraindicated inpatients with ascites because fluid will drain into theair sac and may be aspirated (Color 13.30).

Intercostal Approach to LungsAn intercostal approach to the lung for biopsy hasbeen recently described in the pigeon.11 Entry wasrecommended through the dorsolateral portion of thethird or fourth intercostal space where pulmonarytissue is the thickest in cross section. The third inter-

costal space is located by counting cranially from thelast rib. The space is palpated just ventral to thescapula and a small skin incision is made. The inter-costal muscles are bluntly separated to the level ofthe pleura. Care must be taken during dissectionthrough the intercostal muscle to avoid deep penetra-tion, which can traumatize the surface of the lung.The resulting hemorrhage may make visualizationdifficult and lead to sample artifact.

An instrumented sheath and rigid endoscope areinserted into the incision and maneuvered carefullybetween the ribs so that the surface of the lung canbe visualized. The rounded edges of the sheath aid inatraumatically positioning the instrument. A 5 Frflexible forceps is advanced into the lung paren-chyma, the jaws closed rapidly and removed. Post-bi-opsy hemorrhage may vary from mild to moderatebut is usually controlled by pressure. Intercostalmuscle and skin are closed routinely with simpleinterrupted sutures.

While it is not essential to utilize an endoscope tobiopsy the lung from this site, it was found that thesheath and endoscope combination greatly aided thecollection of quality pulmonary biopsies with lessrisk of trauma to the patient.11 Rigid cup biopsyforceps can be manipulated unaided through a simi-lar intercostal incision, but trauma to the surface ofthe lung may be greater due to the short workingdistance and lack of magnification.

Intestinal Peritoneal CavityThe intestinal peritoneal cavity (IPC) is the largestof the peritoneal cavities. It is a single, midline po-tential space that extends from the level of the kid-neys caudal to the vent. It is somewhat subdivided bythe several mesenteries formed by reflections of theperitoneum that suspend the proventriculus, intes-tines, gonads and supporting structures.16,24 The go-nads are actually suspended within the IPC and arenot located within the abdominal air sac. The confu-sion in this positioning is understandable becausethe gonads are clearly visible from the abdominal airsac even though they are covered by the air sac walland the confluent peritoneum (Color 13.12, 13.13).One method to demonstrate the relationship be-tween the IPC and the abdominal air sac is to insertan endoscope into the IPC, optically guiding it to-ward the left gonad and then viewing this arrange-ment from the abdominal air sac via a second en-doscope (Color 13.25). The thin but substantial airsac/peritoneal wall can be seen clearly covering theendoscope.


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The intimate relationship between the abdominal airsac and the IPC is of greatest clinical significance inthe female bird. The dorsal mesentery, the dorsalparietal peritoneum and the peritoneum covering theleft abdominal air sac fuse to form a serous pocketsurrounding the ovary.24 This “ovarian pocket” is be-lieved to help guide ova to the infundibulum.6 It hasbeen suggested5 that extensive damage to both theright and left abdominal air sacs in female birds willlead to infertility and that trauma should be limitedto only one of the abdominal air sacs. This suggestionignores the presence of the IPC and simplifies therole of the abdominal air sacs. Under routine en-doscopic examination from a lateral approach onlythe lateral wall of the abdominal air sac is pene-trated. The confluent medial wall of the abdominalair sac and the IPC would not be penetrated underthese circumstances. Thus, the ovarian pocket wouldnot be disrupted. A hysterectomy (salpingohysterec-tomy) performed from a lateral approach will disruptthe left IPC membrane.

CloacaThe cloaca is a unique, three-chambered structurethat receives the terminal portions of the colon, ure-ters and reproductive tract. Endoscopic examinationof the three parts of the cloaca is complicated by thepresence of feces and urates. Flushing the proc-todeum with saline and then insufflating the struc-ture while closing the vent lips around the telescopewill enhance viewing. Uroliths,18 papillomatous in-flammation and true prolapse have been documentedwith endoscopy. Bacterial and fungal cloacitis mayalso occur.

Distal Oviduct (Uterus)Endoscopic examination of the distal oviduct (uterus)is possible in reproductively active birds and may bea useful procedure for the sampling and diagnosis ofoviductal disease.

Biopsy Techniques

Patient Considerations

IndicationsOpen (surgical) and percutaneous techniques for bi-opsy of the liver have been described in avian medi-cine. Other internal organs have occasionally been

biopsied using open techniques. The ability to obtainprecise target biopsies of specific organs is a naturalextension of endoscopic examination and offers a farless traumatic method for obtaining diagnostic speci-mens. Carefully selected biopsies of affected organsmay be critical in establishing a diagnosis and allowmore precise therapeutic decisions. Table 13.3 de-scribes approaches and techniques for specific organbiopsies.

Indications for biopsy may include abnormal radio-graphic findings or biochemical parameters, chronicrespiratory disease, polyuria and polydipsia (see Ta-ble 13.2). The endoscopist should be prepared tocollect biopsies during routine examinations. It is notuncommon to find unexpected lesions in patientspresented for gender determination. Specimens fromobvious lesions are easily collected from the borderzone where abnormal meets normal tissue. If thepatient’s history, physical examination or biochemi-cal findings suggest renal or hepatic abnormalities,biopsy of the kidney or liver is indicated. Tissues willfrequently appear grossly normal even though thereare significant histologic lesions present.20

The decision to biopsy the liver or kidney (Color13.43) is frequently made too late in the diseaseprocess to be truly helpful to the patient and client.Sampling the end stage liver is seldom illuminatingbeyond confirming a poor prognosis that should beotherwise clinically evident. Many birds with earlycases of hepatic disease demonstrate few clinicalsigns. Recent advances in avian clinical biochemistryprocedures, particularly the measurement of bile ac-ids, promise to improve the clinician’s ability to de-tect liver disease at an early stage. Bile acids deter-mination is a sensitive and specific indicator of liverdamage (see Chapters 11, 20). Histologic changes areseen in the livers of patients with persistent in-creases in the bile acids of two times or greater thenormal reference intervals. A liver biopsy is recom-mended in cases where the bile acids measurementremains elevated following the completion of therapyfor a systemic disease (eg, chlamydiosis) or wherecontinued elevation of two weeks or more is confirmed.

Renal disease can also be challenging to recognizeand diagnose in its early stages (Color 13.47, 13.48).Elevations in uric acid levels may not occur until arelatively large number of renal tubules have beendamaged. Polyuria is frequently noted. Kidney bi-opsy is recommended when uric acid levels are con-sistently above reference values or show evidence of


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an increasing trend or where polydipsia and polyuriapersist without clinical explanation.

Air sac and pulmonary biopsies are indicated whenclinical examination, radiographic studies or auscul-tation reveal persistent, nonresponsive respiratorydisease. Dyspnea upon exertion is common in parrotswith chronic respiratory disease but is not diagnosticbecause other thoracoabdominal pathology (eg, hepa-tomegaly, abdominal tumors) may also generate thisclinical sign. Generalized pulmonary disease is bestassayed with these techniques although specifictypes of focal lesions may also be sampled (Color13.49).

Biopsies of the spleen are indicated in persistentsystemic diseases where an etiologic diagnosis islacking, in cases of unexplained splenomegaly and ingranulomatous inflammation of the spleen.

Samples of the ventricular serosa and muscularisthat include nerve tissue can be valuable in thedefinitive antemortem diagnosis of neuropathic gas-tric dilatation (NGD). A minimum of two specimensis obtained from the caudoventral surface of the ven-triculus. A site near a branching blood vessel is cho-sen in an attempt to harvest nervous tissue. Thethick ventricular muscularis prevents perforation ofthe viscus. These sites heal well, as only a portion ofthe serosa and outer muscularis is required. Ven-tricular biopsies are preferred for the diagnosis ofNGD over proventricular biopsies because the serosaof the ventriculus can be harvested much more safelywith less risk of perforation due to the thicker mus-cularis. The ventriculus is believed to be the mostimportant site for NGD involvement due to its role inthe motility of the gastrointestinal system. Biopsy ofthe proventriculus is contraindicated due to its thin

TABLE 13.3 Specific Organ Biopsies: Approaches and Techniques

Organ Approach Technique

Liver Best accessed from the VHPC but may also be approachedthrough the left and right caudal thoracic air sac (caudal TAS).

In generalized diseases of the liver, samples can be mosteasily obtained from the hepatic border using a 5 or 7 Frinstrument. In focal disease (eg, granulomas, neoplasia), thelesion should be specifically targeted taking care not to openthe jaws of the forceps too wide when pushing into the liver.This will reduce crush artifact. Larger, rigid forceps can beused but are not usually necessary.

Kidney Through the caudal TAS into the cranial portion of theabdominal air sac (AAS) or via the AAS approach. May alsobe approached directly through the IPC, although thispotential space would need to be insufflated. The caudal TASapproaches are most suitable for reaching the cranial andmiddle divisions of the kidney. Entry into the AAS is anexcellent way to reach the caudal division of the kidney.

Depending upon the size of the patient, 3, 5 or 7 Fr forcepscan be used. Cup-shaped forceps can be used to controldepth of penetration. In some smaller birds, the 5 Fr roundcup forcepsj may be more appropriate than those with astandard elliptical shape.

Air Sac In most species, the caudal TAS is the one most frequentlyinvolved in air sac pathology. Lesions may be moreprominent on one side than another or may involve thecranial TAS more extensively. Radiographs may be mosthelpful in selecting the preferred entry site.

Cup biopsy forceps may be used to grasp a small piece of airsac from the border of an air sac puncture site (eg, the caudalTAS/AAS entry site) or to harvest focal lesions directly fromthe surface of the air sac. Exudate may also be collected withthe forceps for microbiology.

Lung Two approaches to the avian lung were recently described.11

An endoscopically-guided biopsy of the caudal surface of thelung can be collected from the caudal TAS using the Storzsystem. It is also possible to access the costal surface of thelung through an intercostal approach. The Storz system maybe used to enter the intercostal space and visualize the lung,or a rigid forceps may be guided by the surgeon unaided.

5, 7 and 9 Fr forceps have been used to collect pulmonarybiopsies. The degree of localized pulmonary hemorrhage isdirectly related to the size of the biopsy forceps used and thedepth of penetration.

Spleen The spleen is approached from the left AAS. The AAS maybe entered through the caudal TAS or from the caudalapproach. The spleen is located on the right side of theproventriculus near the junction with the ventriculus.

A 5 Fr elliptical cup is satisfactory for most patients.

Ventriculus The greater curvature of the ventriculus, particularly thecaudoventral surface, is best approached from the caudalTAS through the left paralumbar fossa.

A 7 or 9 Fr elliptical forceps is recommended. A minimum oftwo biopsies is collected from the caudoventral surface neara blood vessel to ensure the harvesting of nerve as well asserosa and muscularis.

Testes The right or left testicle can be reached from its respectiveAAS or from the IPC.

A smaller forceps is less traumatic (eg, 5 Fr round) althoughtesticular biopsy utilizing a 9 Fr elliptical cup instrument hasbeen reported.8


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wall and the difficulty in preventing perforation withgastric spillage and peritonitis. Some researchers areinvestigating the possibility of identifying his-topathologic lesions of NGD in biopsies of the crop.

Small, precise biopsies of the testicle may be usefulin the documentation of reproductive failure due todysfunction of the testes. Local and systemic infec-tions may cause testicular lesions, although thesehave been poorly documented.

ContraindicationsThe specific contraindications for biopsy relate toblood clotting. Biopsy collection should be delayed inany avian patient that shows evidence of abnormali-ties of the hemostatic system. This usually becomesevident at the time of blood collection. Most birdsshould show clot formation in one to two minutes.Deficiency of vitamin K is the most common coagula-tion disorder, for which vitamin K1h is administeredpre-surgically (see Chapter 18). The blood filmshould be examined for the presence of adequatethrombocyte numbers.

A biopsy cup shape and diameter appropriate to thesize of the patient and organ to be biopsied must bechosen. Forceps too large for the purpose may causeexcessive organ trauma and hemorrhage.

Biopsy cups generally come in only two shapes:round or elliptical. The round shape does not pene-trate as deeply into tissue as the same diameterelliptical cup and this may be indicated for use withcertain organs such as the kidney or testes.

Inexperience with the instrumentation and ap-proaches to the organ is a potential cause of biopsycomplications.

Instrumentation

Table 13.4 lists selected sources of endoscopic andbiopsy equipment.

A percutaneous technique to biopsy the avian liverusing a 19 ga modified Jamshidi or Menghini needlehas been described.18 The larger, right lobe of theliver was approached through the sternal notch withthe needle directed posteriorly to avoid puncture ofthe heart. The technique is relatively rapid to per-form, but it is a blind procedure. The liver cannot beinspected nor can focal lesions be sampled. Theproventriculus, heart and bile duct are at risk fororgan trauma. Optically guided biopsies of the liverare superior.20 A rigid cup biopsy forceps originally

designed for otolaryngologyi can be guided along theshaft of the endoscope to the visual field. Biopsies ofthe liver, kidney, spleen, air sacs, lung and testes canbe obtained under direct observation. The 8150.00forceps has a 3.0 mm (9 Fr) diameter cup and takesa relatively large, elliptical sample. This instrumentshould not be used in birds under 200 g. This forcepsin combination with a 2.2 or 2.7 mm telescope hasbeen the most widely utilized and accepted methodfor collecting optically guided biopsies in the avianpatient. The forceps is “walked” into position alongthe shaft of the endoscope until it can be visualized.

In an effort to improve the usefulness of endoscopi-cally guided biopsies, a new endoscope and sheathset has been developeda in cooperation with KarlStorz Endoscopy. An instrument channel permits theuse of implements up to 5 Fr (1.7 mm) diameter.Flexible forceps for biopsy and grasping as well asaspiration and infusion cannulas can be placed intothe port of the channel and guided easily to the tip ofthe sheath and into the viewing field of the en-doscope. This single puncture system simplifies themanipulation of instrumentation for the endoscopistand helps prevent additional patient trauma.

The system is appropriate for patients weighing ap-proximately 150 g to 2000 g. In larger birds or atcertain sites (eg, the ventriculus), a heavier biopsyforceps (eg, 7 Fr) is frequently required. This neces-sitates a larger sheath. The advantage of a system-atic approach to endoscopic equipment employingone manufacturer is that a modular design can be

TABLE 13.4 Manufacturers of Endoscopic Equipment

Karl Storz Veterinary Endoscopy-America, Inc.175 B Cremona DriveGoleta, California 93117USA

Richard Wolf Medical Instruments Corp.7046 Lyndon AvenueRosemont, Illinois 60018USA

Olympus Corporation4 Nevada DriveLake Success, New York 11042-1179USA

Orlux Engineering and Instrumentation Ltd.18 Strathearn Avenue, Unit 17 BBrampton, Ontario L6T 4X9CANADA


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Color 13.22 Gross view from the end of the sternum ina cockatoo placed in dorsal recumbency.The sternum (s) has been elevated to accen-tuate the division of the cavities visiblefrom endoscope insertion point 11 (Figure13.2). The confluent wall of the right cra-nial thoracic air sac and right ventral he-patic peritoneal cavity (1), ventral mesen-tery (2) and confluent wall of the left cranialthoracic air sac and left ventral hepaticperitoneal cavity (3) are clearly visible. Theright liver lobe (rl) and left liver lobes (ll)are also visible. The right ventral hepaticperitoneal cavity is marked by arrows; theleft ventral hepatic peritoneal cavity ismarked with open arrows.

Color 13.23 (Insertion point 2 see Figure 13.2) Viewinside the left cranial thoracic air sac of anAmazon parrot. For reference purposes, in-sertion point 2 would provide a similar viewto position D-9 if entering through site 6 asshown in Figure 13.4. Easily identifiablestructures include ribs (r), proventriculus(p), medial intercostal muscle (m), heart(h), attachment of pericardial sac (arrow),lung (lu), ostium of cranial thoracic air sac(open arrow) and liver (li).

Color 13.24 (Insertion Point 2 see Figure 13.2) The en-doscope is in the cranial thoracic air sac,and the contiguous wall between the cra-nial and caudal thoracic air sacs is visiblecaudally (a). In this entry site, the heart (h)will be observed beating cranially. Otherstructures that can be visualized includeribs (r), lung (lu), liver (l), medial intercos-

tal muscle (m) and the ostium for the cra-nial thoracic air sac (arrow).

Color 13.25 (Insertion point 10 see Figure 13.2) An en-doscope placed in the left abdominal air sacwas used to take a picture of a second en-doscope guided into the intestinal perito-neal cavity. Note the membrane (arrow)covering the tip of the endoscope with theintestinal (in) tract under the membrane.Other visible structures include the lung(lu), cranial pole of the left kidney (k),transverse abdominal muscle (m), ilium (i)and proventriculus (p).

Color 13.26 (Insertion point 10 see Figure 13.2) ThisAmazon parrot had been endoscoped frominsertion point 6 and the iatrogenic tearthat was made in the contiguous wall of thecaudal thoracic and abdominal air sac isclearly visible (arrow). Equipment used forendoscopy must be sterile to prevent air sacinfections or peritonitis. The air sacs wereoriginally clear and now are consideredcloudy, and there is an increase in vascu-larization. When viewed from insertionpoint 8, a granuloma is evident in the airsac (g). Other structures that are visibleinclude lung (lu), ilium (i), cranial pole ofthe left kidney (k), loop of intestines (in),proventriculus (p), external iliac vein (openarrow).

Color 13.27 (Insertion point 10 see Figure 13.2) A rentis visible in the contiguous wall of the cau-dal thoracic and abdominal air sac (arrow)showing the path of the endoscope wheninserted at point 6 for gender determina-

tion. Other visible structures include lung(lu), external iliac vein (open arrow), cra-nial division of the left kidney (k1), middledivision of the left kidney (k2), (i) ilium,loops of intestines (in) and proventriculus(p). This represents how a site should ap-pear if the original entry was performedunder aseptic conditions. Compare this toColor 13.26.

Color 13.28 (Insertion point 11 see Figure 13.2) Thenormal endoscopic anatomy of the ventralhepatic peritoneal cavity of a pigeon. Thisview provides clear visualization of thesize, shape and texture of the liver. Thisposition can be used to obtain endoscopi-cally guided biopsies of the liver. Note thatthe right lobe of the liver (rl) extends fur-ther caudally than the left lobe of the liver(ll). Other structures that can be visualizedinclude the sternum (s), deep pectoral mus-cle (m), proventriculus (p) and heart (h).

Color 13.29 A small tear (arrow) has been created in thecaudal thoracic air sac to enter the under-lying left ventral hepatic peritoneal cavityof a normal pigeon. Liver (li), proventricu-lus (p), lung (lu), ostium of caudal thoracicair sac (o), contiguous wall of the caudalthoracic and abdominal air sac (a), contigu-ous wall of the cranial and caudal thoracicair sac (open arrows).

Color 13.30 Left, ventral, hepatic peritoneal cavity dis-tended with air (arrows) following biopsy ofthe liver. Other visible structures includethe lung (lu) and proventriculus (p).

FIG 13.2 (repeated) Numbered endoscopic sites described for evalu-ation of the internal anatomy of birds. Entry sites are shown as eitherleft-sided approaches (open) or right-sided approaches (solid).

FIG 13.4 (repeated) The endoscopist can develop an insight into therelative position of organs as viewed from entry site 6. The views aredivided into four angles (A,B,C,D) and depths (1 through 9). Struc-tures used for orientation include: a) lung b) ostium of the cranialthoracic air sac c) adrenal gland d) gonad e) kidney f) ureter, oviduct,vas deferens area g) abdominal air sac h) caudal thoracic air sac i) liverj) proventriculus k) heart and l) cranial thoracic air sac.

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Color 13.31 An endoscope has been placed in the oralcavity of a Great Horned Owl showing theinfundibular cleft (arrow), sphenopterygoidsalivary glands (ssg), longitudinal folds ofthe esophagus (e), laryngeal mound (openarrow), tongue (t) and mandibular salivaryglands (msg).

Color 13.32 An endoscope has been placed in the oralcavity of a normal African Grey Parrot.Note the dark pigmentation and uniformcoloration and texture of the oral mucosa.Well formed papillae (arrow) are noted oneither side of the choanal slit (c). Also vis-ible are the lateral commissures of themouth (open arrows) and the tongue (t).

Color 13.33 Lateral view of the oral cavity in a Yellow-crowned Amazon Parrot with hypovitami-nosis A. Abscessation (open arrow) at thebase of the tongue (t), and blunting andabscessation of the choanal papillae (ar-row) are characteristic. Hyperkeratosis ofthe tongue and oral mucosa are also noted.

Color 13.34 An endoscope has been placed in the oralcavity of a normal Amazon parrot. Note thesmooth texture of the tissues in the oralmucosa. All secretions are serous in nature.The choanal (arrow) and lingual papillaeare sharp and well defined. Other struc-tures that can be visualized include thetongue (t), oropharynx (o), infundibularcleft (open arrow) and choana (c).

Color 13.35 Endoscopic view of the palate in a GreatHorned Owl. The cranial choanal slit (ar-row) and sphenoptergoid salivary glands(ssg) are visible. Note that the choanal slitdoes not contain papillae, but that papillaeare present on the caudal edge of the sphe-nopterygoid salivary glands.

Color 13.36 Caudal view of the choanal area in an Afri-can Grey Parrot. The visible structures in-clude the choanal slit (c), infundibular cleft(arrow) and endotracheal tube placed in thetrachea (open arrow). Note that the struc-ture of the choanal papillae is different inan African Grey Parrot than in an Amazonparrot (see Color 13.34).

Color 13.37Endoscopic view of the cranial margin ofthe choanal slit in a Moluccan Cockatoo.The nasal septum (n), left middle nasalconcha (arrow) and nasal mucous mem-branes (open arrow) are visible.

Color 13.38 Normal esophagus of a Great Horned Owlshowing longitudinal folds.

Color 13.39 Normal crop of a cockatoo. A red rubberfeeding catheter (t) has been introducedinto the crop and is just ventral to theopening from the crop into the thoracicesophagus (arrow). Normal, clear, bubblymucus is seen covering the crop mucosa.Wrinkling of the crop mucosa (open arrow)is occurring in response to a peristalticwave. Note the smooth, thin texture andeven color of the crop mucosa.

Color 13.40 An endoscope has been passed into thefluid-filled proventriculus of a pigeon. Notethe openings of the proventricular glands(arrow) and a pelleted food particle (openarrow).

Color 13.41 a) An endoscope has been inserted into theexternal ear canal of a Great Horned Owlto show the tympanic membrane (t), extra-columellar cartilage (e), cranial wall of theear canal (arrow) and caudal wall of the earcanal (open arrow). b) Closer view of extra-columellar cartilage.

Color 13.42 Biopsy forceps are being used to take asample from the caudal edge of the left liver

lobe (l). The confluent wall of the caudalthoracic air sac and left ventral hepaticperitoneal cavity membrane are clearly vis-ible (arrow).

Color 13.43 Post-biopsy view of the left liver lobe (l) ina pionus parrot with avian mycobacte-riosis.

Color 13.44 Insertion 6. Post-biopsy photograph of thelung as viewed from within the left caudalthoracic air sac.

Color 13.45 Liver of an Amazon parrot showing severebiliverdin accumulation secondary tochlamydiosis.

Color 13.46 Endoscopic view of the liver (l) prior tobiopsy of several white-to-yellow prolifera-tive masses (arrow). Histopathology indi-cated bile duct carcinoma in an Amazonparrot. This bird had a history of cloacalpapillomatosis.

Color 13.47 (Position B-4 see Figure 13.4) Endoscopicview of the cranial pole of the left kidney inan Amazon parrot showing several white,proliferative masses (arrow). Biopsy indi-cated lymphosarcoma. Other visible struc-tures include the lung (lu).

Color 13.48 (Insertion point 6, postion B-4 see Figure13.4) Endoscopic appearance of chronicglomerulonephritis in an Amazon parrot.The cranial pole of the left kidney (k), com-mon iliac vein (arrow) and ovary (o) areclearly visible.

Color 13.49 Granuloma in the abdominal air sac of apionus parrot. The substantial vascularityof the adjacent air sacs suggests a chronicreaction. The fact that the air sac tissue atthe periphery of the mass is normal sug-gests that the infection has been contained.The spleen (s) is enlarged and pale.


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used. Thus the 2.7 mm endoscope in the standardStorz avian set can be inserted into other sheathssuch as the modified 26156 H, which permits theintroduction and use of the larger 7 Fr biopsy forceps.

Preparation of Small BiopsiesThe biopsies obtained with the types of forceps pre-viously mentioned are small and must be handledwith care so that they are not lost or damaged. Vari-ous techniques have been recommended in the pastto enable the histotechnologist to locate and properlyimbed small specimens for processing. Wrapping tinypieces of tissue in filter paper or a very fine clothbefore immersion in the fixative is one method. Orthe specimens can be placed into a small stopperedblood collection container without anticoagulant.kThis system is simple and effective, allowing thetechnician to clearly visualize the sample(s). No morethan two to three specimens should be placed in eachclearly labelled container. Small tissue samples re-quire far less time to fix than larger samples (likelyless than two hours in formalin). Specifically buff-ered, ten per cent formalin designed for tissue fixa-tion must be used. Failure to do so will lead toprecipitates and artifacts. If biopsies cannot be proc-essed immediately, the specimens can be stored in asolution of 97% methyl alcohol after fixation in orderto ensure sample quality. The laboratory should becontacted for specific recommendations.

Consulting PathologistsThe value of the clinical biopsy is directly related tothe quality of the sample, the history provided andthe experience of the pathologist. Reading small sur-gical biopsies from exotic avian species is a relativelyspecialized area of pathology. Best results are likelyto be obtained by working with a consultant patholo-gist who has a real interest and expertise in this field.Timely reporting of results is essential to enable theclinician to make optimal use of the biopsy information.

Products Mentioned in the Texta. Avian Endoscopy Diagnostic Set, 2.7 mm, Karl Storz

Veterinary Endoscopy, Goleta, CA, 64108 BS, 2.7 mm, 30Telescope, 67065 C Sheath, 67161 Z Biopsy Forceps.

b. Focuscope, MDS Inc, Clearwater, FL c. Gluterex, 3M Medical Products, St. Paul, MN.d. Tegaderm 1626 and 9505, 3M Medical-Surgical Division, St.

Paul, MN, OpSite 4963C, Smith and Nephew Inc., Lachine, QCe. AErrane, Anaquest, Madison, WI; Isoflo, Solvay Animal

Health, Mendota Heights, MNf. Vetwrap, 3M Corp, St. Paul, MNg. Sovereign, Sherwood Medical, St. Louis, MOh. AquaMephyton, MSD, Rahway, NJi. Forceps 8150.00, Richard Wolf Medical, Rosemont, ILj. Storz # 27071 T, Karl Storz Veterinary Endoscopy, Goleta, CA k. Vacutainer red top three ml. tube #6381, Becton Dickinson,

Rutherford, NJ

References and Suggested Reading

1.Bailey RE: Surgery for sexing and ob-serving gonad condition in birds. Auk70:497-499, 1953.

2.Bush M: Laparoscopy in birds andreptiles. In Harrison RM, Wildt DE(eds): Animal Laparoscopy. Balti-more, Williams and Wilkins, l980, pp183-197.

3.Degernes LA, et al: Lead poisoning intrumpeter swans. Proc Assoc AvianVet, , l989, pp l44-l55.

4.Evans HE: Anatomy of the budgeri-gar. In Petrak ML (ed): Diseases ofCage and Aviary Birds 2nd ed. Phila-delphia, Lea and Febiger, 1982, pp111-187.

5.Frankenhuis MT, Kappert HJ: Infertil-ity due to surgery on body cavity in fe-male birds: Cause and prevention.XXII Inter Symp Erkr Zoo-Arnhem,Akademie-Verlag, Berlin, 1980, pp237-239.

6.Goodchild WM: Differentiation of thebody cavities and air sacs of Gallusdomesticus postmortem and their lo-cation in vivo. Br Poult Sci ll:209-215,l970.

7.Harrison GJ: Endoscopic examinationof avian gonadal tissue. Vet MedSmall Anim Clin 73:479-484, l978.

8.Harrison GJ: Endoscopy. In HarrisonGJ, Harrison LR (eds): Clinical Avian

Medicine and Surgery. Philadelphia,WB Saunders Co, l986, pp 224-244.

9.Hopkins HH: Optical principles of theendoscope. In Berci G (ed): En-doscopy. New York, Appleton Cen-tury Crofts, 1976, pp 3-27.

10.Hulka JF: Textbook of Laparoscopy.Orlando, Grune and Stratton, 1985, p11.

11.Hunter DB, Taylor, M: Lung biopsy asa diagnostic technique in avian medi-cine. Proc Assoc Avian Vet, 1992, pp207-211.

12. Ingram KA: Laparotomy techniquefor sex determination of psittacinebirds. J Am Vet Med Assocl73(9):1244-1246, 1978.

13. Ingram KA: Otoscopic technique forsexing birds. In Kirk RW (ed): Cur-rent Veterinary Therapy VII. Phila-delphia, WB Saunders Co, 1980, pp656-658.

14. Johnson AL: Reproduction in the fe-male and male. In Sturkie PD (ed):Avian Physiology 4th ed. New York,Springer Verlag, 1986, p 404.

15. Jones DM, et al: Sex determination ofmonomorphic birds by fibreoptic en-doscopy. Vet Rec 115:596-598, 1984.

16.King AS, McLelland J: Female repro-ductive system. In Birds: Their Struc-ture and Function. London, BalliéreTindall, 1984, pp l45-l65.

17.King AS, McLelland J: Respiratory sys-tem. In Birds: Their Structure andFunction. London, Balliére Tindall,1984, pp 110-144.

18.Kollias GV: Liver biopsy techniquesin avian clinical practice. Vet ClinNorth Am l4(2):287-298, 1984.

19.Kollias GV: Avian endoscopy. In Ja-cobson ER, Kollias GV (eds): Contem-porary Issues in Small Animal Medi-cine, Exotic Animals. New York,Churchill Livingstone, 1988, pp 75-104.

20.Kollias GV, Harrison GJ: Biopsy tech-niques. In Harrison GJ, Harrison LR(eds): Clinical Avian Medicine andSurgery. Philadelphia, WB SaundersCo, 1986, pp 245-249.

21.Lumeij JT: Endoscopy. A Contributionto Clinical Investigative Methods forBirds with Special Reference to theRacing Pigeon (Columbia livia domes-tica). Utrecht, PhD Thesis, 1987, ppl51-166.

22.McDonald SE: Surgical sexing of birdsby laparoscopy. Calif Vet 5:l6-22, l982.

23.McDonald SE: Endoscopic examina-tion. In Burr EW (ed): CompanionBird Medicine. Ames, Iowa State Uni-versity Press, 1987, pp 166-174.

24.McLelland J, King AS: The gross anat-omy of the peritoneal and coelomic

cavities of Gallus domesticus. AnatAnaz Bd 127:480-490, l970.

25.Redig PT: Aspergillosis. In Kirk RW(ed): Current Veterinary TherapyVIII. Philadelphia, WB Saunders Co,1983, pp 611-613.

26.Risser AC: A technique for perform-ing laparotomy on small birds. Con-dor 73:376-379, 1971.

27.Satterfield W: Diagnostic laparoscopyin birds. In Kirk RW (ed): CurrentVeterinary Therapy VII. Philadel-phia, WB Saunders Co, 1980, pp 659-661.

28.Satterfield W: Early diagnosis ofavian tuberculosis by laparoscopyand liver biopsy. In Cooper JE,Greenwood AG (eds): Recent Ad-vances in the Study of Raptor Dis-eases. Keighley, Chiron Publications,1981, pp l05-l06.

29.Taylor M: A morphologic approach tothe endoscopic determination of sexin juvenile macaws. J Assoc AvianVet 3(4):l99-201, 1989.

30.Taylor M: Endoscopy. Proc AssocAvian Vet, Phoenix, 1990, pp 319-323.

31.Taylor M: Endoscopy. LaboratoryManual. Assoc Avian Vet, 1992, pp 1-10.


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avian medicine: princilpes and application

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