any avian patients are small and deli-cate, increasing the risks associated withsurgery. Seemingly minor hemorrhagecan be life-threatening in patients with

such a small blood volume. Their high metabolic rate,small body size, and high ratio of body surface areato body volume predispose them to intraoperativehypoglycemia and hypothermia, the risks of whichincrease as the duration of anesthesia and surgeryincreases. These factors make it crucial that theavian surgeon not only have the procedure wellthought out, but also have any necessary equipmentready and accessible. Exactness, precision, advancedpreparation and minimal anesthesia time are thekeys to success in avian surgery.

Avian blood vessels are relatively thin-walled, tendto course in a more superficial manner and are lessprotected by surrounding tissues than in mammals.Because there is less perivascular tissue in birds,vessels are prone to move within the tissues andretract from the surgeon’s view. Even after radioco-agulation, vessels may relax and begin to leak bloodafter they retract into the tissues. The avian surgeonmust frequently re-evaluate vessels for recurrence ofhemorrhage and should be meticulous with hemosta-sis to prevent surgically induced hypovolemia. Withthe aid of magnification, small blood vessels can beidentified, isolated and coagulated, minimizing therisk of recurrent hemorrhage.

Surgery is frequently a life-prolonging procedure whenapplied correctly to a properly conditioned avian pa-tient; however, birds with severe nutritional and meta-bolic abnormalities do not have the capacity for long-term recovery from many anesthetic and surgicalepisodes. The most common cause of problems associ-ated with elective surgeries is inadequate presurgicalevaluation of the patient, which prevents proper post-surgical recovery. Although some surgical proceduresmust be performed on an emergency basis without thebenefit of a complete medical evaluation and precondi-tioning, in many situations there is adequate time toaccumulate clinical data. In some cases, surgery shouldbe delayed in the patient’s best interest.

M C H A P T E R

40SURGICAL

CONSIDERATIONS

R. Avery Bennett

Patient Evaluation

When possible, a clinical database acquired prior tosurgery should include a complete history, physicalexamination and laboratory data. A minimum data-base for any preoperative evaluation should includehematocrit, total serum solids and WBC. If possible,a complete blood chemistry profile, whole body radio-graphs, electrocardiogram and cultures, if indicated,should be obtained. A blood glucose is useful in An-seriformes and raptors.

Patients with blood glucose of <200 mg/dl shouldreceive 5% dextrose IV intraoperatively. Patientswith total serum solids of <2 mg/dl are usually se-verely debilitated and are poor candidates for surgi-cal recovery. A hematocrit >60% is indicative of dehy-dration, and fluid therapy should be instituted. If thehematocrit is <20%, surgery should be delayed or awhole blood transfusion should be administered.Blood transfusions are best made from donors of thesame species; however, heterologous transfusions ap-pear to be safe and efficacious.7,26 A serum uric acid of>30 mg/dl indicates dehydration (prerenal) or renaldisease. Surgery should always be postponed until apatient is adequately hydrated. The hematocrit andtotal serum solids can be used to determine whetherprimary renal disease is a factor.

Serum cholesterol, AST and LDH activities may behelpful in evaluating the preoperative condition of apatient. Of 54 birds used to evaluate various anes-thetic agents, three deaths occurred, two of whichhad preanesthetic serum parameters: AST=>650IU/l, LDH=>600 IU/L and cholesterol=>700 mg/dl.Many of the birds that survived had high AST andLDH activities but not in combination with a highserum cholesterol level.17

Respiratory recovery time is determined by the timeit takes a bird to return to a prestressed respiratoryrate following two minutes of handling. A return tonormal respiratory rate within three to five minutesindicates respiratory stability adequate for most an-esthetic and surgical procedures. Periods longer thanfive minutes indicate severe respiratory compromise.

The bird’s nitrogen balance should be addressed, espe-cially in birds that have been anorectic for several

days. In a properly hydrated bird, an increase in bodyweight is a good indicator of a positive nitrogen balance.

Birds have relatively little glycogen stored in theliver. A decrease in blood glucose and insulin com-bined with an increase in glucagon stimulate hepaticglycogenolysis. Liver glycogen stores may decreaseas much as 90% during a 24- to 36-hour fast andpotentially quicker in smaller birds.21 Vomiting andregurgitation may occur if the patient is not fasted,and can result in aspiration pneumonia (see Chapter39). A short fast of five to eight hours will helpdecrease the probability of aspiration pneumonia andwill have minimal effects on blood glucose.20 In emer-gency situations when the digestive tract is full, itshould be partially emptied before the bird is placedin dorsal recumbency (see Chapter 39).

When significant hemorrhage is anticipated, intraop-erative IV fluid therapy should be provided. A patientmay be suspected to have a clotting disorder if peri-follicular bleeding occurs during surgical prepara-tion. When a mature feather is removed, there shouldbe virtually no hemorrhage around the follicle.

Nutritional Support

Little is known about the nutritional requirements ofthe various species of companion and aviary birds.Even less is known about how stress, such as surgery,increases the nutritional and caloric requirements ofavian patients. In contrast to starvation, stress maycause an initial hypometabolic state followed by hy-permetabolism,32 which increases the body’s need forprotein. Protein is necessary for tissue repair, anti-body production and blood cell production, all ofwhich are necessary for postsurgical recovery. Carbo-hydrates (not fats) are nitrogen-sparing energysources that best correct a stress-related negativenitrogen balance.32 The postoperative surgical pa-tient must have a positive nitrogen balance to facili-tate tissue repair, and a source of nonprotein energyto meet increased caloric requirements.

The basal metabolic rate (BMR) of inactive animalsmay be determined using the formula BMRkcal/kg/24 hr = K(BWkg 0.75) (see Chapter 15). Addi-tional energy is required for growth, reproduction,disease and tissue repair and is defined as productiveenergy (the amount of energy a bird mobilizes abovethe requirements for existence).41 Stresses such assevere trauma, head injury and sepsis increase thepatient’s energy requirements 1.5 to 3.0 times theminimum energy requirement.13,32 Birds have a higher

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requirement for protein,13,32 and their amino acidrequirements are different from those of mammals.

Liquid diets that can be used to provide assistedalimentation to pre- or postsurgical patients are com-mercially available.13,14,32 Hyperosmolar diets shouldbe diluted (1:1) with water. Only 25% of the calcu-lated requirements should be provided initially inorder to prevent diarrhea. Over a period of two tothree days, the concentration and volume of formulaare gradually increased as the intestines adapt to thehyperosmolar solution.40

The patient’s water requirements must also be met.When using hyperosmolar diets, water may be pulledinto the intestine, which contributes to dehydration.Water requirements vary with species, diet, size, ageand environmental temperature (see Chapter 15).32

Patient Preparation

Feather ControlIn preparing the skin for surgery, feathers surround-ing the proposed surgical site should be gentlyplucked for a distance of two to three centimeters.The contour and covert feathers of the body grow inpterylae or tracts, which are separated by featherlessareas (apteria). These feathers may be easily andsafely removed individually if plucked in the samedirection as their growth. The large flight feathers(remiges and retrices) are attached to the periosteumof the underlying bone and have highly developedfeather muscles and ligaments. Removing thesefeathers is painful and is best accomplished while thepatient is anesthetized. When flight feathers must beremoved, they should be removed individually byholding the feather at its base and pulling in thedirection of feather growth. To avoid injury to theskin, muscles and periosteal attachments, the otherhand is used to carefully secure the tissues at thebase of the feather while it is being removed (seeFigure 15.12).28

Small feathers should be pulled in groups of three orfour in a direction opposite their growth.1,18,28 If theskin has been damaged or torn, the feathers in thisarea can be cut to avoid further damage to the skin.10

Cut feathers are replaced only during the normalmolt cycle.

Excess feather removal will reduce a bird’s insulatingability, increase metabolic demand during the recov-ery period (energy used to regrow the feathers)28 and,if primary or secondary feathers are removed, the

bird will not be able to fly until they regrow. Theremoval of primary and secondary feathers should beavoided because it is easy to damage the follicle,resulting in the growth of malformed replacementfeathers. Flight feathers are molted one at a time andrequire the structural support of the adjacent feath-ers for proper growth. Because the skin of birds isvery fragile and tears easily, removal of feathers is adelicate procedure, and attempting to remove toomany feathers too quickly may result in bruising andtearing of the skin. Feathers in adjacent pterylae canbe retracted using a stockinette, masking tape orwater-soluble gel.1,18,28 Water-soluble gels will pre-vent clear plastic drapes from properly adhering tothe skin and should not be used in this situation.

Creating a Sterile FieldStandard aseptic technique30,39 must be adhered towhen performing surgery on avian patients. Poortechnique may have devastating consequences. Skinpreparation solutions are used to decrease the num-ber of bacteria present on the skin surface to mini-mize the risk of bacterial contamination of the sur-gery site. They should accomplish this objectivewithout damaging the skin and predisposing thepatient to dermatitis.27

Concentrations of chlorhexidine diacetate (0.05%)aand povidone iodine (1.0%)b are effective for skinpreparation. Although studies have shown these con-centrations to be cytotoxic in vitro, they do not havea significant clinical effect on wound healing. Chlor-hexidine gluconate (4%)c is equally effective whenrinsed with saline or alcohol. A saline rinse has beenfound to leave sufficient residual chlorhexidine glu-conate bound to the skin to be effective. This isbeneficial in avian patients where the use of alcoholpredisposes to hypothermia. When povidone iodine(1%) was used as a skin preparation, approximately

CL INICAL APPL ICAT IONSClinical pathology parameters for which postponement of sur-gery may be necessary include:

PCV: <20% - delay surgery or provide blood transfusion >60% = dehydration; give fluid therapy

Total solids: <2 mg/dl = severe debilitation

Blood glucose (raptors, Anseriformes): <200 mg/dl - give 2.5-5% dextrose

Uric acid: >30 mg/dl = dehydration (prerenal) or renal dis-ease

AST: >650 IU/dl

LDH: >600 IU/dl

Cholesterol: >700 mg/dl

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50% of the treated dogs developed erythema, edema,papules, wheals and “weeping” of serum from theskin surface.27 Chlorhexidine is generally preferredover povidone iodine solution as a patient prepara-tion27 because it has a broader spectrum of antimicro-bial activity, longer residual antimicrobial activity, isefficacious in the presence of blood and organic mat-ter and is nontoxic and hypoallergenic. However, inclinical settings, the type of scrub solution used hasnot been found to affect the rate of wound infections.34

It is challenging to create a sterile field of the wingbecause of the large flight feathers, which should notbe removed unless absolutely necessary. The primaryand secondary flight feathers can be wrapped to-gether with masking tape. The surgeon can thencover the entire wing with a sterile stockinette orself-adherent bandage materiald creating a sterilefield (Figure 40.1).28

Patient drapes are currently available in a variety ofsizes, shapes and materials. With avian patientsclear drapes are recommended, as they allow thesurgeon and anesthetist to visually monitor the pa-tient during the procedure. Clear plastic drapes arecommercially availablee with or without povidoneiodine impregnation. These drapes have an adhesivethat will stick to dry avian skin and create a sterilefield, but must be removed with care to preventdamaging the tissue. These drapes conform closely tothe patient’s body, are lightweight, disposable andinexpensive, and allow the anesthetist to monitorrespiratory movements. As an alternative, a clear

plastic drape can be made from plastic kitchen wrap.The border of the plastic should be edged with mask-ing tape, making it easy to find the edges and openthe drape. These drapes can be folded with a sheet ofplastic but must be gas sterilized and are not adhesive.

In most cases, the plastic drape is small and does notallow the surgeon to create a sterile field incorporat-ing the entire surgery table and instrument stand. Inorder create such a field, the clear plastic drape isplaced over the patient and a large drape sheet witha central fenestration large enough to allow thedraped patient to be exposed, is placed over theentire field. This will prevent accidental contamina-tion of the arms and elbows by touching them to anundraped table.

Perioperative antibiotic therapy involves the use ofantibiotics such that there are therapeutic tissuelevels of the agent present at the time of exposure tobacteria. With most antibiotics, parenteral admini-stration one to two hours preoperatively, and main-taining therapeutic doses for 8 to 16 hours postopera-tively, will accomplish this goal. Unless there isinfection or significant contamination, use of antibi-otics beyond this period is not indicated and has beenshown not to decrease the incidence of surgicalwound infections.

Wound Healing

Wound healing has been thoroughly studied in mam-mals, and five phases have been described: the in-flammatory stage, the fibroblastic phase, the epi-thelialization phase, the contraction phase and theremodeling phase.29,31 The cellular and vascularevents of the inflammatory phase have been studiedin chickens.2,8,10,24,25 The inflammatory response inbirds is similar to that classically described in mam-mals with early vasoconstriction to initiate hemosta-sis, followed by vasodilation within 30 minutes.25,31

Bradykinin, histamine, 5-hydroxytryptamine andother chemical mediators initiate the acute inflam-matory phase of wound healing in birds.2 During thefirst two to six hours, large numbers of heterophils,basophils and monocytes migrate into the woundmargins.8,25 Phagocytosis of cellular debris and bac-teria begins during this phase. After 12 hours thereis a shift in the cellular response from one of primar-ily polymorphonuclear leukocytes initially to one ofprimarily mononuclear cells such as lymphocytes,plasma cells, macrophages and monocytes.25 Duringthe next 36 hours, macrophages and multinucleatedgiant cells begin to phagocytize those leukocytes that

FIG 40.1 Feather removal in preparation for surgery should besufficient to allow the establishment of a sterile field but not sosevere that the bird is predisposed to hypothermia. In this case,the feathers from the mid-diaphysial humerus to the carpus wereremoved to prepare the bird for the placement of an external fixatorto repair a fractured ulna. The primary feathers were clipped andwrapped in a self-adherent bandage material to facilitate thecreation of a sterile field without removal of the primary feathers.

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have been involved in the early phagocytosis of tissuedebris and bacteria. Fibroblasts begin to appear atthe wound margins and proliferate over the next fewdays.

As soon as necrotic tissue, blood clots and otherdebris are removed by phagocytic cells, fibroblastsmove into the damaged tissue. In the inflammatoryphase, the exudate contains fibrinogen, which is con-verted to fibrin by the release of tissue enzymes. Thisacts as a hemostatic barrier and a scaffolding forother repair elements such as the incoming fi-broblasts. New capillaries enter immediately behindthe migrating fibroblasts. They contain plasminogenactivator that is necessary for the breakdown of thefibrin. Collagen is synthesized during this fibroblas-tic phase beginning on the third or fourth day inbirds8 and on the fourth or fifth day in mammals.31

The collagen bundles are initially small, but gradu-ally enlarge to form dense collagen networks thatbind the edges of the wound together. The fibroblasticphase of healing lasts two to four weeks. As thecontent of collagen increases, the number of fi-broblasts decreases, and the capillaries begin to re-gress. Eventually, the rate of collagen productionroughly equals the rate of collagen destruction.31

The epithelialization phase is characterized by themigration of epithelial cells from the wound margin.The epidermal basal cells are normally adhered toeach other. These adhesions break down, allowingthe cells to be mobilized. The cells enlarge and mi-grate down and across the wound. These cells do notbegin to proliferate until the entire wound surfacehas been covered by a single layer of epithelial cells.Eventually, the normal epithelial thickness is re-stored.

The contraction phase is described as “the process bywhich the size of a full-thickness open wound isdiminished and is characterized by the centripetalmovement of the whole thickness of surroundingskin.”29 Several mechanisms have been theorized tobe responsible for this action.31

The remodeling phase is described in terms of earlywound strength and late wound strength.31 There isno appreciable gain in wound strength during thefirst four to six days of healing. However, the fibrinclot, epithelialization and ingrowth of new capillariesoccur early and provide some support to the wound.After the early fibroblastic phase, wound strengthincreases to an early maximum at 14 to 16 days,paralleling the rise in collagen content of the

wound.31 Late wound strength occurs as a result ofcollagen maturation. The collagen content stabilizesafter the third week. Wound strength may continueto increase for a period of years following the stabili-zation of the collagen content resulting from theintramolecular and intermolecular cross linking ofcollagen fibers.

Freshly created (within eight hours), uncomplicatedwounds should be treated by primary closure withanticipated first intention healing;5 however, this isnot appropriate for the treatment of open, contami-nated wounds.

Instrumentation

Instuments for avian surgery should be appropriateto the patient’s size. In many cases, ophthalmic in-struments are suitable and should be included in thestandard avian surgery pack. Iris scissors (curvedand straight), forceps with fine teeth, micro Halsteadmosquito forceps, jeweler’s forceps (curved andstraight), iris hooks, eyelid retractors for abdominalretractors, retinal forceps, adventitia scissors, springhandled scissors and Castroviejo needle holders areparticularly useful (Figure 40.2). Because avian tis-sues are delicate, the use of toothed forceps is seldomappropriate. Debakey-type forceps are relativelyatraumatic and serve well in avian surgery. Penrosedrains or other sterile rubber materials may be usedto wrap around structures for elevation or retraction,and eyelid retractors work well as wound retractors(Figure 40.3). A sterile gavage or feeding tube can beused for irrigation or for flushing out hollow viscera(such as the proventriculus during proventriculo-tomy). Various sizes of bone curettes are useful toretrieve foreign bodies from the ventriculus orproventriculus. A tuberculin syringe with an at-tached 25 ga needle can be fashioned into a tissuehook by bending the tip of the needle 45 to 90° underthe operating microscope.

A mini-Frazier suction tip is well suited for aviansurgery because of its small, delicate size. This typeof suction tip also has a small hole at the finger rest,which the surgeon may use to adjust the amount ofsuction created at the tip. Red rubber urinary cathe-ters and infant feeding tubes are available in varyingsizes and may be cut off and adapted for use as a

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suction tip. Care must be taken with this type of tipand a powerful suction unit in order not to damageviscera inadvertently suctioned against the tip. Thestrength of suction can be controlled on most suctionunits and should be adjusted so that fluids can beevacuated without damaging tissues. A Poole-typesuction tip can be fashioned from a catheter by cut-ting multiple fenestrations along the terminal two tothree centimeters of the catheter. By having manyfenestrations, the suction force is distributed amongthe inlets, decreasing the force at any one hole. Addi-tionally, if some of the holes are occluded by tissue,the remaining inlets continue to evacuate the celomiccavity.

A one- to three-millimeter rigid endoscope is helpfulfor visualizing areas that the surgeon may not beable to access with the operating microscope (eg,lumen of hollow viscera). Abdominal retractors ap-propriate for small avian patients should maintainretraction but not have blades that extend deep intothe body cavity. Mini-Balfour retractors are useful inlarge patients such as macaws and cockatoos, Almretractors are appropriate for medium-sized patientslike Amazons and conures, and Heiss retractors workwell in small avian patients including cockatiels andbudgerigars.

In many situations, the placement of ligatures indeep surgical sites is unachievable or results in un-acceptable tissue damage due to the relative inacces-sibility and delicate nature of avian tissues. Hemo-static clipsh,i are best for controlling bleeding in these

cases. Multiple-sized clips should be available to ad-dress varied-sized patients and different surgicalneeds. The major expense is encountered in purchas-ing the applier, as the clips themselves are relativelyinexpensive. The appliers are available eitherstraight or with a 45° bend. The bent-tipped applieris useful for deep clip placement; however, the bent-tipped instruments are about twice the size of theequivalent straight-tipped applier, making themmore cumbersome to use. Generally, the small andmedium clips are used most frequently.

Number 15 and No. 11 scalpel blades are most appro-priate for avian surgery. Small gauze pads (2 x 2) andsterile cotton-tipped applicators should also be avail-able (see Figure 40.2). Surgical spearsj are small,wedge-shaped, highly absorbent, synthetic spongesattached to a stick. The point of the spear providescritical control when working under magnification.

FIG 40.2 Ophthalmic instrumentation is best suited for use in birds.

FIG 40.3 Various types of lid retractors are ideal for use in main-taining access to the abdomen of birds. In this photograph, a lidretractor is being used to maintain an opening in the left abdomi-nal wall. The seventh rib (r) has been isolated and cut ventrally tofacilitate its removal for better access to the proventriculus. Sev-eral rents can be seen in the relatively clear caudal abdominal airsac (arrow) just to the left of the rib. The proventriculus (p) andventriculus (v) can be seen deep to the surgical site.

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Absorbable gelatin spongesk are valuable for control-ling hemorrhage, as is oxidized regenerated cellulose.l

With avian patients it is best to place the patient ona restraint board, which is then placed on the operat-ing table. This allows the surgical assistant to movethe patient intraoperatively to acheive proper visu-alization of structures. This is especially importantwhen using the operating microscope as it is mucheasier to move the patient than to move and refocusthe microscope (Figure 40.4). Such boards are com-mercially availablem or can be easily constructedfrom a plastic container lid, a piece of styrofoam or asection of cardboard. Any material that is used shouldbe disposable or sterilizable. Tape restraints are pre-ferred over velcro restraints because they are dispos-able and minimize the risk of disease transmission.

An ideal monitor for the surgical patient would beeasy to apply, unaffected by the surgical environ-ment, economically priced and provide data on thepatient’s heart rate, respiration, body temperatureand hemoglobin oxygen saturation. The high heartrate and small tidal volume of small avian patientsare not easily detected by traditional monitors. Pulseoximeters have become standard in human anesthe-sia but may be unable to detect the high pulse rate ofsome smaller patients. Sensitive respiratory moni-tors that have a thermistor that extends to the end ofan endotracheal tuben are effective in intubated pa-

tients but do not function properly if the patient ismaintained using a face mask (see Chapter 39). Re-mote thermometers are available at a reasonableprice.o The best monitor for surgical anesthesia is stilla well trained and experienced surgical technician.

Radiosurgery (Electrosurgery)

Radiosurgery employs high frequency (two to fourmHz), alternating current to generate energy waves,which create vibration and molecular heat insideindividual cells, causing water to vaporize and thecells to rupture while the active electrode remainscool (Figure 40.5).15,16,19,33,38 Most electrosurgical unitsgenerate wave forms in the frequency range of radiowaves, making the term radiosurgery applicable. Thefrequency can be varied to achieve either cutting oftissues or coagulation of vessels. Coagulation occurswhen the current density is sufficient to dehydratecells and coagulate their organic contents.16,19,33,38

When set for monopolar operation, a radiosurgeryunit employs two electrodes (an active electrode andan indifferent electrode or ground plate), which con-centrate the current density at the tip of the smaller(active) electrode. Monopolar radiosurgical tech-niques are acceptable for gross tissue manipulationsin avian patients weighing more than two kilograms.These are analogous to a broadcast antenna (activeelectrode) and a receiving antenna (indifferent elec-trode) for radio transmission. The ground (indiffer-ent electrode) should be large and placed as close aspossible to the surgical area, and the contact with thepatient should be improved using an electrode paste.It is important to keep the active electrode clean andfree of char and debris. A dirty electrode will drag

FIG 40.4 Surgical boards made of sterilizable materials are help-ful to facilitate the movement of patients undergoing microsurgicalprocedures. An anesthetized cockatiel hen has been taped to asurgical board in preparation for a hysterectomy.

FIG 40.5 Radiosurgery units are indispensable in avian practice.Versatile units are available that also have numerous applicationsin mammalian surgery (courtesy of Ellman Intl. Mfg. Inc.).

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through the tissue, inhibiting the cutting action andincreasing tissue coagulation, which can delay heal-ing and predispose the wound to dehiscence.15,16,19

Many types of active electrode tips are commerciallyavailable. Ball-type electrodes create a lot of tissuedestruction and are used for fulguration and coagu-lation of large vessels. Loop electrodes are used tocontour tisses, obtain organ biopsies and removelarge masses in a piecemeal fashion. Skin incisionsand incisions into other fine tissues are best accom-plished with fine wire electrodes.

Bipolar ForcepsBipolar radiosurgical forceps are superior to monopo-lar forceps in patients weighing less than two kilo-grams and when manipulating tissues in the realmof microsurgery. With bipolar forceps a ground plateis not needed as one of the tips serves as the activeelectrode and the other as the indifferent electrode(Figure 40.6). Compared with the fine-needle or wiremonopolar electrodes, the tips of the bipolar forcepsare broader, allowing the current to be dispersed justenough to accomplish the tissue welding that is criti-cal for hemostasis. The current passes from one tip(active electrode), through the contacted tissue andto the other electrode (indifferent) without passingthrough the entire patient. In avian patients, bipolarforceps induce less reflex hemorrhage and provideimproved tissue control. With the two electrodes insuch close proximity, the transmitted wave currentsare different from those generated with the monopo-

lar system, resulting in precise control of energyapplication.

Some commercially available bipolar ophthalmic for-ceps are slightly wider than is ideal for avian surgery.These forceps can be made more appropriate foravian surgery by using a fine sharpening stone toreduce the width of the tips. It is best to make theactive electrode tip slightly narrower than the indif-ferent tip. Forceps with the active electrode slightlybent are commercially available and are best foravian surgery.p The energy passes through the tissuebetween these tips in a manner not attainable withunmodified, straight-tipped bipolar forceps. A lowerenergy setting can be used with these forceps. Withthe Surgitron,q the fully filtered wave pattern of thecutting settings are used most commonly. The unit isset at 1 for vessel coagulation, 2 for muscle transec-tion, and 3 for incision of dry skin. For vessels thatare difficult to coagulate, the cutting/coagulationsettings may occasionally be indicated. The coagula-tion setting is used primarily for tissue fulguration(such as the destruction of cloacal papillomas).

Incision TechniquesThe Harrison modified bipolar forcepsp may be usedto make primary skin incisions, coagulate cutaneousvessels prior to blade incision and coagulate individ-ual vessels. These forceps may also be used with orwithout current for tissue dissection. Skin incisionsshould be planned in a manner to minimize the effecton feathers and feather tracts and to avoid the majorblood supply to feathers. The skin is tented withthumb forceps and grasped with the bipolar forcepsat the location of the proposed incision (Figure 40.7).

The current is activated (using a foot switch) pre-cisely as the grasp on the tissue is relaxed slightly,and with a smooth, rapid motion, the forceps arepulled off the tissue.15,16 When correctly applied, afine, white blanching of the tissues occurs with abarely discernible separation of the skin that can beseen under magnification. This will create a smallincision in the tissue that may then be parted toallow introduction of the indifferent electrode of thebipolar forceps (non-bent tip). The electrode is in-serted subcutaneously to the extent of the proposedincision. The electrodes of the bipolar forceps arelightly apposed, the current is activated and theforceps withdrawn. This creates a skin incision withminimal damage. If properly performed, the skinshould remain a normal color except immediatelyadjacent to the incision (which should be white), andthere should be no hemorrhage.15

FIG 40.6 Several styles of bipolar forceps are available. The topone has been specifically designed for avian microsurgical applica-tion. These tips are thinner than normal bipolar tips and the activeelectrode has a 45° bend to facilitate cutting of avian tissues(courtesy of Ellman Intl. Mfg. Inc.).

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When thicker tissue is to be transected, small bitesof tissue are grasped with the bipolar forceps, thecurrent is activated and the forceps are withdrawnthrough the tissue, creating a small nick. This proc-ess is repeated until the tissue is completely tran-sected, stroke by stroke.

Coagulation TechniquesIf hemorrhage is encountered, a sterile cotton-tippedapplicator is used to dry the area for radiocoagula-tion, which cannot be achieved in a wet field. Theswab is rolled toward the source of blood flow withgentle pressure to serve as a tourniquet (Figure40.8). The pressure is relaxed slightly to identify thesource of hemorrhage. Once the vessel is identified,the slightly broader, flat indifferent electrode isplaced under the vessel, and the bent-tipped, activeelectrode is loosely apposed to occlude the vessel. Thecurrent is activated as the forceps are relaxed, seal-ing the vessel. At high current or coagulation set-tings, the vessel frequently retracts within the tissuedue to vasospasm. This results in temporary hemo-stasis only. As the vessel relaxes, the hemorrhagerecurs.

When using monopolar radiosurgery, the power set-tings vary with the type and size of the electrode, thearea of electrode surface in contact with tissue, thenature of the tissue, the operation performed (cut orcoagulation) and the depth of the incision desired.Higher settings are necessary with tough tissues,deep incisions and large electrodes. Healing afterradioincision is by first intention. When used cor-rectly for creating an incision, the current should beactivated before touching tissue, and the electrodeshould glide effortlessly, producing only a slight color

FIG 40.7 a) When possible, the site for a skin incision is chosen byselecting an area that does not pass directly through a featherfollicle. A small nick incision is made with a scalpel or by raisingthe skin slightly with a pair of forceps and grasping the tissue withthe bipolar forceps. b) The indifferent electrode of the bipolarforceps is then inserted under the skin, the tips are gently apposedand the forceps are pulled out of the nick incision in a straight line.c) The length of the bloodless incision line can be increased asneeded. Note that the skin is incised between, not through, thefeather follicles.

FIG 40.8 A cotton swab is used to roll toward a bleeding vessel and,with gentle pressure, to occlude the vessel, stop the bleeding andallow the identification and coagulation of the severed vessel.

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change in the tissue. When used for coagulation, theelectrode should be activated after contacting thetissue and should produce a white spot at the site ofenergy transfer. Current applied repeatedly to thesame area will cause excessive heating and damageto underlying tissues.

A radio current may pass through any portion of theexposed metal portion of the electrode. When thecurrent is activated, it is important to be certain thatonly the tissue to be cut or coagulated is in contactwith the metal portion of the electrode tip. This isespecially important when attempting to coagulatevessels in the abdominal cavity through a small inci-sion in a small bird. If the electrode inadvertentlytouches other structures (abdominal wall, parenchy-mous organs), the current will pass from the elec-trode through the first tissue it touches and exit atthe ground plate, potentially without even contactingthe intended tissue. Most bipolar forceps are insu-lated such that only the tips are exposed. This re-duces the likelihood of errors causing unwanted dam-age to adjacent structures.

The fine-tipped monopolar electrode requires ahigher setting when used on avian tissues than whenused on thicker mammalian skin. When a vessel isencountered at these high settings, the electrode hasa tendency to cut rather than coagulate the vessel,resulting in hemorrhage. A second effort must thenbe made to locate the vessel and coagulate it sepa-rately, creating the potential to induce more damageto the vessel and surrounding tissues. In mammals,the tissues surrounding vessels will heat slightlywith the application of radiocurrent, which helps sealany transected vessels.

The application of a bipolar radiosurgical unit toavian practice and to veterinary practice in generalis limited only by the time that the clinician spendsin practicing with this equipment. Each radiosurgi-cal unit requires precise adjustments that must beperformed by the surgeon who will be using theinstrument. Time invested in practicing with a radio-surgical unit will be well worth the improvement inclinical results.

Magnification

The hands and fingers are able to accomplish tasksof intricate detail, and vision is generally the limitingfactor in surgical procedures. Therefore, some form ofmagnification is recommended for avian surgery33

and is an integral part of an avian specialty practice.

Operating MicroscopeIn patients weighing less than a kilogram, an operat-ing microscope and microsurgical instrumentationare mandatory and would be considered advanta-geous in larger birds. Using microsurgical tech-niques, severed nerves and vessels, which if left un-repaired would result in a dysfunctional post-fracturelimb, can be anastomosed. Binocular magnificationloupes of 2.5x to 8x are adequate for many proce-dures. Head sets with higher magnification usuallycreate disorientation because of the constant micro-movements of the head. Attaching a fiberoptic lampto the loupe facilitates vision. With the use of magni-fication, individual vessels are more easily identifiedfor coagulation, minimizing the degree of hemor-rhage associated with a procedure.1,19,33 Because mi-nor hand tremors are magnified, it is recommendedthat microsurgeons abstain from the use of alcohol,caffeine, other stimulants and heavy exercise prior tosurgery.16 The major disadvantage of performing sur-gery under an operating microscope is that it gener-ally requires more time to complete a procedure thanwhen a magnification loupe is used.

The operating microscope should have a lens objec-tive of approximately 150 mm with 12.5 mm ocularlenses.12 An electronic zoom is advantageous. A fi-beroptic ring light can be attached to the lens forimproved illumination of the surgical field. This typeof ring light can be connected to most standard en-doscope light sources. Bright white light is critical forvisualization during microsurgery. Microscopes areexpensive, but used and reconditioned models arebecoming more readily available.

Microsurgical InstrumentsThere are four requirements for microsurgical in-struments: they should be long, be counterbalanced,have round handles and have miniaturized tips (Fig-ure 40.9).16 It is important that only the tips of micro-surgical instruments are miniaturized. The handlesshould be of normal length to help provide stabilityto the tips and diminish the effect of hand tremors.The handles should be long enough to rest comfort-ably in the hand between the thumb and index finger.The instrument should be held like a fine writinginstrument and be manipulated with minimal pres-sure. Gripping the instrument will fatigue the handand fingers, causing motion at the tips. Microsurgicalinstruments have a counterbalance and are con-toured to rest in the groove between the thumb andindex finger. They should lie in the hand and not fallout when the grip is released (Figure 40.10). Thehandles should be round (except for scissors) to facili-

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tate a rolling action that results in smooth, precise,flowing movements at the tip. This rolling motion isespecially important for delicate cutting, suturingand knot-tying. It is important to note that totallyminiaturized instruments (older generation of oph-thalmic instruments) are not appropriate for micro-surgery. These instruments have short shanks andhandles, and their use under the operating micro-scope results in loss of balance and control leading tofast, jerky movements.

The microsurgical pack should include micro-scis-sors, micro-needle holders and a variety of micro-for-

ceps. Needle holders should not have a clasp or boxlock, as the motion that occurs when the lock is setand released is enough to cause the needle to teartissues. Inexpensive forceps can be fashioned by plac-ing vulcanized silicone on the handles of jewelryforceps. Layers of liquid plastic (dispensed from a hotglue gun) may be applied to the handles to achievethe necessary round shape. An ophthalmic Castro-viejo needle holder can be modified for microsurgeryby grinding the tip narrower, removing the box lockand making the handle round.12,16

For microvascular work, specialized clips are used tomaintain the severed ends of the vessel in approxi-mation. A colored background is placed under thevessel to improve contrast and make identification ofthe vessel easier. These backgrounds are commer-cially availabler or can be made from pieces of balloonappropriately sterilized. Vessel dilators are also nec-essary. A vascular irrigation system can be madeusing a 27 or 30 ga needle, the tip of which has beencut off and polished smooth so it will not damage thevascular intima. A motorized rotary tool and theoperating microscope are used to modify the needle.Heparinized irrigation solution in a hand syringewith the modified needle attached is used to clear thevessel of clots and debris.12,16 Suture material forsmall avian patients usually is of 6-0 to 10-0 size,while for microvascular work, 10-0 nylon suture on a75 micron needle is routinely used.12

Developing Microsurgical SkillsThe avian surgeon should take advantage of everyopportunity to gain experience. Human plastic sur-geons and microvascular surgeons are valuable re-sources. Continuing education courses and opportu-

FIG 40.9 A microsurgical needle holder with long, rounded,counter-balanced handles and miniaturized tips is compared to astandard needle holder.

FIG 40.10 a) The handles of microsurgical instruments should be of sufficient length to allow them to rest comfortably in the groove betweenthe thumb and index finger. b) Miniaturized instruments are difficult to manipulate and cause increased fatigue of the hands during use.

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nities to practice on cadaver specimens are also valu-able. Prior to practicing on tissues, it is helpful togain experience manipulating objects under magnifi-cation by picking up and moving small objects (eg,canary seeds) with the microsurgical instruments. Aslit can be placed in a latex glove to practice sutureplacement and knot tying. Initially, the clinicianmust develop new eye-hand coordination, and it isimportant to develop dexterity with both hands un-der the operating microscope. Microsurgery is tedi-ous, time-consuming work, and it is imperative thatthe surgeon be comfortable. Prior to the onset of theprocedure, the height of the table and chair should beadjusted for the surgeon’s maximum comfort. Motionfrom the shoulders and arms should be minimized byresting the mid-antebrachium along the edge of thetable to serve as a fulcrum. The fourth and fifthfingers should also rest on the table to provide asecond fulcrum and additional stability. The handsshould be relaxed, and any motion should originatefrom the wrists and fingers, resulting in smooth,accurate paint brush-type movements. Breathingpatterns should be natural. Breath-holding results intremors at the instrument tips.16

Suture Materials

The goals of incision repair are to limit the adverseeffects of the repair technique and to restrict the lossof tissue function. In routine avian surgery, suturesizes of 3-0 to 6-0 are most commonly used.18 Forsmall patients and microsurgery, sutures of 10-0 maybe necessary. Companion birds may have a ratherformidable beak that could easily remove the tough-est materials; however, they generally do not trau-matize suture lines.1 This characteristic allows theuse of continuous patterns in the skin of many avianpatients. Topical medications, splints and bandagesare not well tolerated by companion birds.

Many factors should be considered when selecting anappropriate suture material for a given procedure.The tissue characteristics, the presence of contami-nation or infection and the characteristics of thesuture material influence the selection. The ability ofsuture material to potentiate infection is roughlyproportionate to the inflammatory reaction causedby the suture.36 The inflammatory response and re-action to various suture materials differ betweenbirds and mammals. A number of factors influencethe amount of inflammation a suture material in-duces including the surface area of material exposedto the tissue, the tissue in which the material is used(ie, fascia does not react to silk while intestines and

skin react strongly), the method of placement (tightsutures strangulate tissue), the length of time thematerial has been present (some sutures stimulate areaction shortly after placement but become inactivewithin a few months) and the chemical properties ofthe material.36,37

Suture is a foreign material in a surgical wound andmay potentiate infection. Bacteria may be protectedfrom the body’s defenses within the suture material.By reducing the amount of material implanted (thefewest number of sutures and the smallest diameterpossible to accomplish the task) and minimizing sur-gical tissue trauma, the risk of suture-related infec-tion may be diminished.36,37 Braided sutures shouldnot be used in contaminated or infected wounds asthey delay the clearance of bacteria, prolonging andpromoting inflammation.36 Bacteria are better ableto bind to braided materials than monofilament su-ture made of the same material. Where there iscontamination or infection, a monofilament, nonre-active material such as nylon is indicated, as it willnot allow bacterial wicking and will retain its tensilestrength long enough for resolution of the infectionand completion of tissue healing. In a study of theability of bacteria to adhere to suture material it wasfound that monofilament, nonabsorbable materialshave the least capacity for adherence while polygly-colic acid and polyglactin 910 have the most.36

Sutures that act as a wick to allow transport of serumand bacteria are called capillary sutures.37 They maypotentiate the spread of infection from a contami-nated or infected tissue into a sterile area.36 Multi-filament sutures are also more likely to cause theformation of suture sinus tracts and granulomasthan monofilament materials. The advantage ofbraided sutures is that they generally have betterhandling characteristics.

The extent of tissue damage during suture placementalso influences the reaction and the risk of infection.Sutures should be placed with a minimum amount ofboth intrinsic (tension on tissue within the loop ofsuture material) and extrinsic (tension on surround-ing tissues) tension. Knots must be securely tied, yetthe surgeon must attempt to use the least amount ofsuture material to decrease the foreign body reaction.It is important to use the fewest throws to create asecure knot, which will fail by suture breakage andnot by knot failure. For chromic catgut, polyglactin910, polyglycolic acid and polypropylene, threethrows are required and four are required for polydi-oxanone and nylon.35 When starting and finishing a

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continuous pattern, a different number of throws isrequired to create a secure knot. To start a continu-ous pattern with polygycolic acid, polyglactin 910and polypropylene three throws are required. Fourare required for chromic catgut and five for polydiox-anone. When ending a continuous pattern, it takesfive throws for polypropylene, chromic catgut andpolyglycolic acid, six for nylon and polyglactin 910,and seven for polydioxanone to create a secure knot.

After considering suture characteristics, tissue inter-action and the processes of wound healing, the finalfactor in suture selection is personal preference. Thetechnique of suture placement and tissue handlingremains more important for uncomplicated woundhealing than the selection of suture material.37 Theplacement of sutures in a manner that allows accu-rate tissue apposition appears to be more critical inavian patients than in mammals. Tension and theresultant tearing of tissue in birds dictates the use ofmore sutures per centimeter, less intrinsic tension(within the suture loop) and atraumatic insertion.Most avian tissues have low tensile strength. It isimportant to use the smallest swaged-on atraumaticneedle that is available for a particular suture. Manyvisceral organs are very delicate and require that thesurgeon develop specialized handling techniques.

Evaluation of Suture Materials in BirdsThe tissue reaction to five suture materials (poly-glactin 910, polydioxanone suture, monofilament ny-lon, medium chromic catgut and monofilament stain-less steel) in pigeons was evaluated at 3, 7, 15, 30, 60,90 and 120 days following implantation in the bodywall.4 In mammals, it is known that chromic catgutis absorbed by the action of proteolytic enzymes re-leased from monocytes. The pigeons in this studydeveloped a marked granulocytic inflammatory re-sponse the the catgut that diminished during theperiod of evaluation; however, the material was stillpresent at the end of the study indicating prolongedabsorption of the material. Polyglactin 910 is consid-ered nonreactive in mammals. It is absorbed by theprocess of hydrolysis and does not require enzymedegradation. In this study, polyglactin 910 caused themost intense inflammatory reaction but it was ab-sorbed the most quickly (completely gone by day 60).Polydioxanone is a monofilament material, which,like polyglactin 910, is absorbed by hydrolysis. It isconsidered nonreactive in mammals and is usuallycompletely absorbed by 180 days after implantation.This material behaved similarly in the pigeons stud-ied. It caused minimal tissue reaction and absorptionwas underway at the close of the study.

Nylon and stainless steel cause minimal tissue reac-tion but are nonabsorbable. In the pigeons, theycaused minimal tissue reaction but, because they arestiff and potentially more mechanically irritating tosurrounding tissues, they were more often associatedwith hematoma, seroma and caseogranuloma forma-tion. Based on the findings reported in this study,chromic catgut should be avoided in avian surgery.Slowly absorbed monofilament, synthetic materialsabsorbed by hydrolysis rather than proteolysis aremost appropriate when wound healing is expected tobe prolonged. Rapidly absorbed, braided, syntheticmaterials absorbed by hydrolysis are best used whenthe benefit of rapid absorption outweighs the disad-vantage of a pronounced inflammatory reaction.

(The editors have experienced some adverse reactionswith Polyglactin 910 in psittacine birds; thereforethey personally use nylon for subcutaneous suturesand stainless steel wire for skin.)

Tissue AdhesivesTissue adhesives of cyanoacrylate have many appli-cations in avian medicine and surgery. The cy-anoacrylate monomer is a liquid that polymerizes inthe presence of the small amount of water present intissues. The time required for the liquid to becomesolid and bond tissues depends on the amount ofwater (more water present will delay curing) and thethickness of the acrylic applied (thicker will delaycuring). Medical grade adhesivess are biologically in-ert and cause minimal tissue reaction. Some preferto use the less expensive commercial grade of glue(eg, SuperGlue); however, these contain substancesthat are toxic to tissues6,19 and are not recommendedfor medical use.

These materials hold tissues in approximation toallow healing to progress; however, cells cannot pene-trate the adhesive. It is important not to allow theadhesive to run between the tissues to be apposed asthe presence of the acrylic will delay healing bycreating a physical barrier. In some cases, especiallywith water birds, the acrylic may be applied in a thinlayer over the apposed incision to create a seal yetallow epithelial cells to migrate under the acrylicduring the healing process. These adhesives mayalso be used to secure IV catheters in place, to attachthe limbs or digits of tiny patients to splints fororthopedic problems and various other purposes.Caution should be exercised when using these mate-rials in the presence of anesthetic gases with whichthey are synergistic and may cause ocular irritationand vomiting in avian patients.19

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Postoperative Care

The patient should be placed in an incubator at 85°Fwith supplemental oxygen during recovery from sur-gery. It is best to continue maintaining the postsur-gical patient in a small, controlled environment dur-ing the convalescent period (see Chapter 39). Thepatient’s activity level should be kept to a minimumto allow proper tissue healing. A square, box-typeenclosure is preferred and in most circumstancesperches should be removed or lowered to decrease thelikelihood of falling. Food and water should be placedwhere they are easily accessed by the patient. Toysand extraneous objects within the enclosure shouldbe removed.

Postoperative antibiotic therapy should be institutedwhen there is a specific indication, such as with open,contaminated wounds or where there has been in-traoperative contamination of the surgical field. IMperioperative antibiotic therapy is recommended forgeneral prophylaxis in these cases.

In general, avian patients do not traumatize theirsurgical incisions, and they poorly tolerate bandagesand other devices. Elizabethan collars or neck bracesshould be reserved for the most desperate cases. If anElizabethan collar is considered necessary, the pa-tient’s neck should first be wrapped so the collar willbe held in position against the mandible. Using thistechnique, a smaller, looser collar may be utilized.22

In some patients, the center core of cardboard from aroll of bathroom tissue may be padded and used as aneck brace alone or in conjunction with an Elizabe-than collar. The first day, the Elizabethan collarshould open rostrally in the traditional manner. Thiswill allow the patient time to become accustomed tothe collar, and it will not damage the wings while thepatient is struggling to escape the device. The secondday, the collar should be reversed such that the coneopens caudally. This will allow the patient moreready access to food and water. The patient should bekept in a plain box with nothing to trap and hold thecollar. Food and water should be placed on a pedestalfor easy access. The patient’s weight should be closelymonitored to assure that an adequate amount of foodand water is being consumed. The collar should be

regularly evaluated for evidence of pressure oresophageal obstruction.

AnalgesicsHistorically, it has been considered that birds have aremarkable capacity to deal with pain, although theassessment of what animals perceive as pain is diffi-cult. Research in the area of avian pain perceptionhas been minimal. Companion birds have a welldeveloped sense of touch and react by loud vocaliza-tion and withdrawal when potentially painful stim-uli are applied. Clients expect that analgesia will beprovided for their pet, and it is the responsibility ofthe entire staff to relieve a patient’s postoperativepain and suffering.

Some research has been conducted with respect to painin pigeons and poultry. One study was conducted inbudgerigars3 to evaluate the effect of high doses ofbutorphanol tartratet and flunixin meglumineu onheart rate, motor control and respiratory rate.

Butorphanol is an opioid analgesic with both agonistand antagonist properties, resulting in a “ceiling effect”such that above a maximum effective dose, neitherbeneficial nor deleterious effects are noted. The actionand potency of opiates and opioids is related to thespecific receptor sites to which a given agent binds.3

There are three major types of opiate receptors. Mureceptors mediate analgesia and euphoria. They arealso responsible for physical dependency, sedationand respiratory suppression. Kappa receptors alsoare involved in analgesia and, to a lesser degree, withsedation and respiratory depression. Sigma receptorstimulation results in cardiac and respiratory stimu-lation, anxiety and hallucinations.

Butorphanol exerts its effects at mu and kappa re-ceptors. Doses of 3 to 4 mg/kg of butorphanol given tobudgerigars had no statistically significant effect onheart rate or respiratory rate;3 however, some treatedbirds lost motor control. This effect was consideredminor and all birds remained alert. Return to normalmotor coordination occurred within two to four hourspost-administration. No gastrointestinal effects wereobserved with this agent. This study did not evaluatethe minimum and maximum effective doses. It wouldbe advisable to start with a standard dose of 0.2 to0.4 mg/kg of butorphanol, recognizing that doses upto ten times this dose are safe in birds.

Buprenorphine hydrochloridev is another opioid withagonist/antagonist activity that appears to be effec-tive in controlling pain in avian patients. A dose of

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0.01 to 0.05 mg/kg IM appears to provide adequatepostoperative analgesia.23

Flunixin meglumine is a nonsteroidal anti-inflamma-tory agent that is a potent analgesic for certain types ofpain; however, surgical pain is rarely responsive to thisclass of analgesic, and it is more appropriate for use inthe treatment of inflammatory conditions. It has beenrecommended for use as an analgesic in companionbirds at 1 to 10 mg/kg SID IM or IV.9,23 Flunixin at 10mg/kg had no effect on respiratory or heart rates inbudgerigars.3 Additionally, motor function remainednormal following IM administration of flunixin. Regur-gitation or vomiting occurred within two to five mini-utes after administration in five of six patients. Tenes-mus was also observed several minutes afteradministration of flunixin. Aspirin has been recom-mended at a dose of one 5 gr tablet dissolved in 250 mldrinking water. These nonsteroidal agents have thepotential to cause serious gastrointestinal side effectsand may prolong clotting time. They should be usedwith caution until their benefits and limitations arebetter understood.

Products Mentioned in the Texta. Nolvasan Solution, Fort Dodge Laboratories, Inc,

Fort Dodge, IAb. Betadine Solution, The Purdue Frederick Co, Norwalk, CT c. Hibiclens, Stuart Pharmaceuticals Division of ICI America,

Inc, Wilmington, DEd. Vetrap, 3M Company, St. Paul, MNe. Incise, Johnson & Johnson Co, Inc., New Brunswick, NJf. Safe & Warm, Safe & Warm, Inc., Boulder City, NVg. Heiss blunt retractors, small Alm retractors - Fine Science

Tools, Foster City, CAh. Ligaclip, Pitman Moore, Mundeleing, ILi. Hemoclip, Weck, Solvay Animal Health, Inc,

Mendota Heights, MNj. Weck-Cell Surgical Spears, Solvay Animal Health, Inc.,

Mendota Heights, MNk. Gelfoam, Upjohn Co., Kalamazoo, MIl. Surgicel, Johnson & Johnson Co, Inc., New Brunswick, NJm. Miami Vise, Henry Schein, NYn. The Beeper, Spencer Instrumentation, Irvine, CAo. Model Bat-12, Sensortek, Santa Clara, CAp. Harrison Modified Bipolar Forceps, Ellman Intl. Mfg,

Hewlett, NYq. Surgitron, Ellman Intl. Manufacturing, Hewlett, NYr. Visual Background, Ethicon, Somerville, NJs. TissuGlu, Ellman Intl. Mfg, Hewlett, NYt. Torbugesic, Fort Dodge Laboratories, Fort Dodge, IAu. Banamine, Schering Corp, Kenilworth, NJv. Buprenex, Rickitt & Colman, Hull, England

References and Suggested Reading

1.Altman RB: General principles ofavian surgery. Comp Cont Ed PracVet 3:177-183, 1985.

2.Awadhiya RP, et al: Studies on acuteinflammation in the chicken usingmesentery as a test system. Res VetSci 29:172-180, 1980.

3.Bauck L: Analgesics in avian medi-cine. Proc Assoc Avian Vet, 1990, pp239-244.

4.Bennett RA, Yeager M, Trapp A, et al:Tissue reaction to five suture materi-als in pigeons (Columbia livia). ProcAssoc Avian Vet, 1992, pp 212-218.

5.Bojrab MJ: A Handbook on Veteri-nary Wound Management. Boston,Kendall Co, 1981.

6.Boothe HW: Suture materials and tis-sue adhesive. In Slatter DH (ed):Textbook of Small Animal Surgery.Philadelphia, WB Saunders Co, 1985,pp 334-343.

7.Bos JH, et al: Treatment of anemicbirds with iron dextran therapy: Ho-mologous and heterologous bloodtransfusions. Proc Assoc Avian Vet,1990, pp 221-225.

8.Carlson HC, Allen JR: The acute in-flammatory reaction in chicken skin:Blood cellular response. Avian Dis13:817-833, 1969.

9.Clubb SL: Therapeutics. In HarrisonGJ, Harrison LR (eds): Clinical AvianMedicine and Surgery. Philadelphia,WB Saunders Co, 1986, pp 327-355.

10.Degernes LA: Soft tissue wound man-agement in avian patients. Proc As-soc Avian Vet, 1990, pp 182-190.

11.Degernes LA, et al: Preliminary re-port on the use of total parenteral nu-trition in birds. Proc Assoc Avian Vet,1992, pp 19-20.

12.Doyle JE: Introduction to microsur-gery. In Harrison GJ, Harrison LR(eds): Clinical Avian Medicine andSurgery. Philadelphia, WB SaundersCo, 1986, pp 568-576.

13.Fowler ME: Nutrition in injured anddiseased birds: Proc Avian PediatricSeminar, 1990, pp 115-121.

14.Goring RL, et al: Needle catheter duo-denostomy: A technique for duodenalalimentation of birds. J Am Vet MedAssoc 189:1017-1019, 1986.

15.Greene JA: Electrosurgery. In BojrabMJ (ed): Current Techniques inSmall Animal Surgery 3rd ed. Phila-delphia, Lea & Febiger, 1990, pp 40-41.

16.Harrison GJ: New aspects of aviansurgery. Vet Clin No Am Sm AnimPract 14:363-380, 1984.

17.Harrison GJ: Evaluation and supportof the surgical patient. In HarrisonGJ, Harrison LR (eds): Clinical AvianMedicine and Surgery. Philadelphia,WB Saunders Co, 1986, pp 543-549.

18.Harrison GJ: Selected surgical proce-dures. In Harrison GJ, Harrison LR(eds): Clinical Avian Medicine andSurgery, Philadelphia, WB SaundersCo, 1986, pp 577-595.

19.Harrison GJ: Surgical instrumenta-tion and special techniques. In Harri-son GJ and Harrison LR (eds): Clini-cal Avian Medicine and Surgery.Philadelphia, WB Saunders Co, 1986,pp 560-567.

20.Harrison GJ: Preanesthetic fastingrecommended. J Assoc Avian Vet5(3):126, 1991.

21.Hazelwood RL: Carbohydrate metabo-lism. In Sturkie PD (ed): Avian Physi-ology 4th ed. New York, Springer-Ver-lag, 1986, pp 303-325.

22.Janeczek F: Pipe foam collar. J AssocAvian Vet 5(4):191, 1991.

23.Jenkins JR: Postoperative care. SemAvian Exotic Pet Med 2(2):97-102,1993.

24.Jain NK, et al: Studies on acute in-flammation in the chicken using ter-pentine-induced pleuroperitonitis asa test system. Vet Rec 110:421-422,1982.

25.Jortner BS, Adams WR: Turpentine-in-duced inflammation in the chicken. Alight- and electron-microscope study,with emphasis on the macrophage,epithelioid cell, and multinucleate gi-ant cell reaction. Avian Dis 15:533-550, 1971.

26.Martin HD: Resection of a false aneu-rysm in a cockatiel (Nymphicus hol-landicus). J Assoc Avian Vet 5(3):142-146, 1991.

27.Osuna DJ, DeYoung DJ, Walker RL:Comparison of three skin preparationtechniques in the dog. Part 1: Experi-mental trial. Vet Surg 19:14-19, 1990.

28.Paul-Murphy J: Feather plucking inpreparation for surgery. J AssocAvian Vet 1:17, 1989.

29.Peacock EE, Van Winkel W: WoundRepair. Philadelphia, WB SaundersCo.

30.Powers DL: Preparation of the surgi-cal patient. In Slatter DH (ed): Text-book of Small Animal Surgery. Phila-delphia, WB Saunders Co, 1985, pp279-284.

31.Probst CW, Bright RM: Wound heal-ing. In Slatter DH (ed): Textbook ofSmall Animal Surgery. Philadelphia,WB Saunders Co, 1985, pp 28-37.

32.Quesenberry KE, et al: Nutritionalsupport of the avian patient. Proc As-soc Avian Vet, 1989, pp 11-19.

33.Ritchie BW, Doyle JE, Harrison GJ: Mi-cro Techniques for the Surgical Man-agement of Avian Diseases. Res InstAvian Med, Nut & Repro, LakeWorth, 1990, pp 13-18.

34.Romatowski J: Prevention and con-trol of surgical wound infection. JAm Vet Med Assoc 194:107-114,1989.

35.Rosin E, Robinson GM: Knot securityof suture materials. Vet Surg 18:269-273, 1989.

36.Smeak DD, Wendelburg KL: Choosingsuture materials for use in contami-nated or infected wounds. CompCont Ed Pract Vet 11:467-475, 1989.

37.Smeak DD: Selection and use of cur-rently available suture materials. InBojrab MJ (ed): Current Techniquesin Small Animal Surgery 3rd ed.Philadelphia, Lea & Febiger, 1990,pp 34-39.

38.Toombs JP, Crowe, DT Jr: Operativetechniques. In Slatter DH (ed): Text-book of Small Animal Surgery. Phila-delphia, WB Saunders Co, 1985, pp310-333.

39.Wagner SD: Preparation of the surgi-cal team. In Saltter DH (ed): Text-book of Small Animal Surgery.Phildelphia, WB Saunders Co, 1985,pp 269-278.

40.Wheeler SL, McGuire BH: Enteral nu-tritional support. In Kirk RW (ed):Current Veterinary Therapy X. Phila-delphia, WB Saunders Co, 1989, pp30-36.

41.Whittow GC: Energy metabolism. InSturkie PD (ed): Avian Physiology4th ed. New York, Springer-Verlag,1986, pp 253-268.

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