Topics in Medicine and SurgeryTopics in Medicine and Surgery

Radiosurgery and Laser in Zoological Practice:Separating Fact from FictionStephen J. Hernandez-Divers, BVetMed, DZooMed, MRCVS, Dip. ACZM, RCVS Specialist in zoo

and wildlife medicine

garnet [Nd

Journal of E

Abstract

With increasing equipment acquisition by private practitioners, laser and radio-surgery units can no longer be considered as advanced tools of the referralveterinarian. Unfortunately, much of the marketing, lay publications, and con-ference presentations surrounding these instruments have been based on anec-dote and opinion rather than science. This review aims to re-address the balance byconsolidating and presenting the scientific literature on CO2 laser and 4.0-MHzradiosurgery, in particular by citing those studies that have directly compared thesesurgical devices side by side. It is hoped that this information may provide theveterinarian with objective criteria that may be helpful when considering such amajor equipment purchase. Copyright 2008 Elsevier Inc. All rights reserved.

Key words: zoological medicine; exotic pets; surgery; laser; radiosurgery

Over the past 10 years, there has been a dra-matic increase in advanced technologiesand their adoption in veterinary practice.

One area that has seen an almost meteoric rise is theapplication of surgical devices such as lasers andradiosurgery units.1-5 Unsubstantiated claims andmarketing have played significant roles in persuad-ing practitioners to purchase many of these devices,especially laser units; and, indeed, many practiceshave in turn used the laser in their marketing strat-egies to clients, while some have even adopted theterm “laser” in their practice name. Many individualsand practices have invested in the laser phenome-non despite a lack of credible data to support theirpopularity. The author’s first experiences with laserwere with an 810-nm diode laser while in privatepractice in England in 1997. At that time, this wasmost likely the first veterinary laser used in practicein the United Kingdom. Today, at the University ofGeorgia, as with many university hospitals and refer-ral centers, surgeons have access t o multiple lasers(diode, CO2 , a n d neodymium-yttrium-aluminum

-YAG]), as well as 3.8-MHz and 4.0-MHz

xotic Pet Medicine, Vol 17, No 3 ( July), 2008: pp 16

radiosurgery devices. However, these devices are nolonger restricted to the referral specialist, with manyprivate practices boasting of a CO2 laser and/orradiosurgery unit among their inventory.

Intrigued by the upsurge in general interest andveterinary magazine publications hailing the benefits

From the University of Georgia, College of Veterinary Medicine,Department of Small Animal Medicine and Surgery, Athens, GAUSA.

Disclaimer: All laser and radiosurgery equipment used at theUniversity of Georgia’s Veterinary Teaching Hospital has beenpaid for, and none was donated or loaned by interested companies.In keeping with the Royal College of Veterinary Surgeons’ (Lon-don, UK) guidelines for professional conduct, the author does notendorse any particular product or company.

Address correspondence to: Dr. Stephen J. Hernandez-Divers,University of Georgia, College of Veterinary Medicine, Departmentof Small Animal Medicine and Surgery, 501 DW Brooks Dr,Athens, GA 30602-7390. E-mail: shdivers@vet.uga.edu.

© 2008 Elsevier Inc. All rights reserved.1557-5063/08/1703-$30.00

doi:10.1053/j.jepm.2008.05.003

5–174 165

166 Hernandez-Divers

of CO2 lasers and radiosurgery in companion animalpractice, a detailed review was undertaken. There islittle peer-reviewed veterinary literature and notmuch more from our human counterparts whencomparing surgical tissue reaction between that oflaser and radiosurgery technologies. This article com-pares and summarizes the methodologies, tissue ef-fects, healing, and postoperative pain associated withCO2 lasers and 4.0-MHz radiosurgery units, and brieflyreports on the findings of comparative veterinary stud-ies involving dogs, pigeons, and green iguanas. It ishoped that this information will enable practitioners tomake more informed decisions regarding the purchaseof expensive surgical equipment.

Physics

RadiosurgeryElectrical current has been used in medical equip-ment for over a century. Traditional electrocauteryand low-frequency electrosurgery consists of a plati-num wire heated with an electric current, and hasthe ability to both cut and coagulate tissues. Furtherdevelopment led to the advent of alternating currentand transformer circuitry, which could producehigh-electric currents that were used in medicine tocoagulate, cut, and destroy tissues. In 1978, Manessand colleagues discovered that high radiowave fre-quencies (3.8 MHz) were preferred for cutting softtissues.6 This frequency served as the starting pointfor modern radiosurgery units, but has subsequentlybeen surpassed by the development of 4.0-MHzunits. Surgery performed with a modern radiosurgi-cal unit should not be confused with the resultsobtained with electrocautery, low-frequency electro-surgery, diathermy, spark gap generators, or partiallyrectified devices that do not provide surgical cuttingwaveforms. The modern radiosurgery units dis-cussed here use ultra-high frequencies to vaporizeintracellular water, which accurately destroys cellswith minimal collateral damage.

LaserThe term laser stands for “light amplification by thestimulated emission of radiation” and relies on theproduction of electromagnetic radiation in responseto photon emission by the lasing medium.2 Photonsare directed from the optical laser chamber as co-herent, monochromatic electromagnetic radiation.These photons are transmitted, via a series of lensesand delivery fibers, in a focused and controlled man-ner called a laser beam (Fig 1). The wavelength and

frequency of this radiation are peculiar to the specific

lasing medium. CO2 units selectively vaporize intracel-lular water and destroy cells with minimal collateraldamage, whereas diode lasers are more selective forpigments (especially melanin and hemoglobin), maybe less effective in pale or avascular tissues, and tend toprovide deeper penetration with greater collateraldamage when used in noncontact mode.

Equipment

RadiosurgeryThere is only one manufacturer of veterinary equip-ment and 2 models available; the long-established 3.8-MHz and the more advanced and expensive 4.0-MHzdual radiofrequency units (Fig 2). Both of these unitsoffer monopolar/bipolar applications with foot-pedal/

Figure 1. Diagrammatic representation of laser. The top diagramdemonstrates the resting lasing medium molecules within the opticallaser chamber. As energy in the form of electrical current is applied,these molecules attain a higher energy level and become unstable(middle). There is a constant effort to return to a more stable state,and the molecules achieve this by losing energy in the form ofphotons (bottom). These photons leave the optical chamber via thelaser fiber output as a monochromatic laser beam.

finger switch control for several waveforms (Fig 3):

(B) 4

Radiosurgery and Laser in Zoological Practice 167

1. Pure filtered waveform (pure micro-smooth cut-ting): for skin incisions and wire loop excisionswhere hemostasis is not expected to be a problem;creates minimal thermal damage, comparable tofocused small-spot CO2 laser incisions.7-9

2. Fully rectified waveform (blended cutting andcoagulation): used where bleeding might be ex-pected; cuts as well as coagulates small bloodvessels and gives slight lateral heat to the tissues.

3. Partially rectified waveform: primarily used forhemostasis; not used for cutting but is excellentfor coagulation.

4. Fulguration (spark-gap tissue destruction): similarto the unipolar diathermy and gives superficialtissue damage by holding the needle electrodeclose to the tissue and allowing a stream of sparksto burn the tissues; suitable for superficial hemo-

Figure 2. (A) 3.8-MHz and

Figure 3. The different radiosurgery waveforms and their surgical

uses (photo courtesy of Ellman International, Inc., Hewlett, NY USA).

stasis and destruction of cysts and superficial neo-plasms.

5. Bipolar coagulation: precise hemostasis usingbipolar forceps; each blade is connected to theradiosurgery unit so that the current passes be-tween the points of the forceps.

All the above selections are effected through but-tons and displays, which give the operator feedbackof the unit’s operating status. The power level foreach mode is indicated by front-panel digital displays(4.0-MHz unit), which also indicate self-test andmonitoring modalities. The final output power con-trol is made through foot and/or hand switches. Mo-nopolar cutting needles are typically used for dissec-tion, wire loops for tissue biopsies or tissue debride-ment, and bipolar forceps for sealing blood vessels (Fig4). In addition, a wide variety of soft tissue, dental,microsurgical, and endoscopic instruments are avail-able for use with the radiosurgery unit, which makes itversatile for a range of applications in veterinary prac-tice. Radiosurgery requires tissue contact and providestactile feedback, but it is important to keep the elec-trode clean to avoid tissue drag.

LaserThere are a variety of lasers available, but CO2 mod-els (10,600 nm) are probably most common in vet-erinary medicine today, largely because they offerthe advantages of minimal tissue penetration and areduced collateral thermal injury when comparedwith diode lasers (Fig 5, A).1 CO2 lasers consist of abase unit and a delivery arm. The base unit may betabletop or on wheels, and permits the surgeon tochoose the power output and wave form:

1. Continuous: laser energy is supplied as a con-

.0-MHz radiosurgery units.

tinuous beam.

168 Hernandez-Divers

2. Pulse: laser energy is supplied as high-ampli-tude, short-duration pulses, followed by shortpauses during which tissue is allowed to cool.

3. Superpulse: high-pulse frequencies, around 200per second, permit primary incisions whilemaintaining lower tissue temperatures.

The laser beam is activated by a foot pedal andtransferred from the base unit to the ceramic handpiece by either an articulated arm or a flexiblewaveguide. The characteristics of the laser beam as itemerges from the ceramic hand piece can be con-trolled in 2 ways:

Figure 4. Radiosurgery in practice. (A) Radiosurgical arthrotomy incusing bipolar dissection and hemostasis in a ferret.

Figure 5. (A) CO2 laser. (B)

1. The size of the ceramic tip can range from 0.25 to1.0 mm, although 0.8 mm appears to be mostpopular in veterinary medicine. The smaller thetip, the smaller the focused spot size of the beam.

2. The laser beam can be focused to create a point(similar in diameter to the ceramic tip size) atthe tissue interface for cutting, or defocused bymoving the tip further away from the tissue tocreate a larger diameter at the tissue interfacefor thermal damage and ablation.

CO2 laser hand pieces and ceramic probes do notcontact the tissue, and therefore there is no tissue

into the stifle of a black-footed penguin. (B) Adrenal gland isolation

ision

980-nm diode laser.

Radiosurgery and Laser in Zoological Practice 169

drag but a lack of tactile feedback (Fig 6, A). Unlikeradiosurgery and diode lasers, CO2 units cannot beused in a liquid medium. There are few terminalattachments for the CO2 laser, and, although there isa probe available for the 2.7-mm telescope, their useendoscopically is generally impractical.

Diode lasers are less common and generallycheaper to purchase. They are also composed of abase unit that provides a laser beam of 810 or 980nm (Fig 5, B). This lower wavelength is absorbedpreferentially by pigmented tissues (e.g., hemoglo-bin and melanin), but can traverse liquid environ-ments. The beam is activated by a foot pedal andtransferred from the base unit to the hand piece bya flexible quartz fiber ranging from 200 to 1000 �min diameter. The flexibility of the fibers makes thislaser much more versatile with regards to use via theinstrument channel of most rigid and flexible endo-scopes (Fig 6, B). The diode laser can be used incontinuous or pulse modes in 2 ways:

1. Noncontact mode: the laser beam emanatesfrom the end of the fiber and continues until itis absorbed by pigment; as a result, the beammay travel up to 4 mm into tissue and can causesignificant damage below the tissue surface.However, diode lasers are also able to seal largerblood vessels than other lasers, up to 2 mm indiameter.

2. Contact mode: the terminal end of the fiber iscoated with a fine layer of carbon (most easily

Figure 6. Laser surgery in practice. (A) Proximal tail amputation inof cloacal papilloma in a macaw; the diode laser is delivered by anunaffected papilloma (p).

accomplished by activating the laser beam while

holding a tongue depressor against the terminaltip); the laser beam is completely absorbed atthe carbon-coated tip, which becomes superheated and can be used to ablate tissue; theadvantage here is that there is no laser penetra-tion into the tissue, but thermal collateral cellu-lar damage is greater.

Staff Safety

To prevent retinal damage to personnel in the op-erating room, it is essential that protective glasses beworn at all times when lasers are in use.10 The safetyglasses need to be appropriate for the wavelength ofthe laser being used (Fig 7, A). Likewise, the pa-tient’s eyes should also be protected by gauze ordrapes, unless specifically operating on the oculartissues. Finally, windows in the operating roomshould be covered to prevent potential damage tononsurgical personnel outside of the operatingsuite. All CO2 and diode lasers come with emergencycut-off switches that can be operated by persons inthe room, or when a door is opened.10 No suchocular health issues exist with the use of radiosur-gery.

The use of laser or radiosurgery on biologicaltissue produces a smoke plume that may containpyrolysis products that are known to be cytotoxic.11,12

This smoke, which can contain viable bacterial, viral,or patient DNA, should always be evacuated with a

en iguana using CO2 laser. (B) Endoscopic diode laser coagulationl fiber (f ), and coagulated tissue (c) is clearly demarcated from the

a greoptica

filtered vacuum from the surgical site (Fig 7, B).

170 Hernandez-Divers

Purchase Costs

Table 1 details the purchase costs obtained from thesole radiosurgery distributor and one of many veter-inary laser distributors in the United States.

Tissue Effects

All CO2 lasers and radiosurgery units cause cellulardestruction in the same way—the vaporization of

Table 1. Current sources and list prices for rEllman International, Inc.3333 Royal AveOceanside, NY 11572 USATel: 1-800-835-5355, ext. 6512Fax: 1-516-569-0054www.ellman.com

3.4.

Lumenis, Inc. (AccuVet)5302 Betsy Ross DrSanta Clara, CA 95054 USATel: 1-877-586-3647, ext. 3997Fax: 1-800-783-5671www.lumenis.com

DiDiCOCONo

Prices were obtained from a company representative in November 200

Figure 7. Occupational safety. (A) Appropriate protective glassesevacuation devices are required when using laser or radiosurgery.

intracellular water. The way this energy is deliveredto cause vaporization differs, but the end result is thesame. It should, therefore, come as no surprise thatthe tissue effects are very similar—an immediate areaof vaporization, surrounded by a zone of irreversiblecoagulative necrosis, and a further zone of reversibleedema and inflammation (Fig 8).

With proper technique, collateral damage is min-imal with both small-spot focused CO2 lasers andmicro-fiber radiosurgery set to pure cut mode. Ul-

surgery and laser units in the United Statesz Surgitron radiosurgery unit, $4,300z Surgitron radiosurgery unit, $18,000

980 nm 15 W, $16,995980 nm 25 W, $19,995er 12 W, $21,000er 20 W, $29,000ulse CO2 laser 20 W with superpulse, $33,500

face masks are required when working with lasers. (B) Smoke

adio8-MH0-MH

odeode

2 las2 lasva p

7.

and

Radiosurgery and Laser in Zoological Practice 171

trafine incisions permit delicate and precise dissec-tion with reduced tissue damage and less postoper-ative inflammation. However, despite the suggestionthat radiosurgery and lasers can be used to harvesttissue biopsies, there will always be a degree of coag-ulative artifact that may hinder the histopathologicalevaluation at the biopsy margins.13 In cases wheremargin evaluation is critical (e.g., tumor resection),the use of the scalpel to collect biopsy samples maystill be preferred. At the extreme of minimal dam-age, surgical devices are less effective at maintaininghemostasis (the least damaging incisional device isthe scalpel blade, which is well known to cause hem-orrhage). Conversely, diode lasers can seal vessels upto 2 mm in diameter by virtue of their greater col-lateral damage. Therefore, the benefits of minimalcollateral damage must be weighed against the needfor hemostasis. For example, greater collateral dam-age and cellular destruction would be preferablewhen dissecting through vascular tissue or ablatingneoplastic cells. This can be achieved with radiosur-gical coagulation or fulgaration modes, or by usingthe defocused CO2 laser beam.

In general, radiosurgical and CO2 laser incisions

Figure 8. General effects of laser or radiosurgery on soft tissue (t ).Energy provided by the laser beam or radiosurgical electrode (e)causes intracellular water to vaporize, which causes cellular ablation(v). A thin layer of char (c), may be present and is surrounded by anarea of irreversible coagulative necrosis (n). The combined thicknessof char and necrosis equates to the collateral thermal damagecaused by the device during surgery. A larger zone of reversibleedema and inflammation (i) develops within minutes or hours ofsurgery but later resolves.

cause less collateral damage than cryosurgery, elec-

trocautery, and diode lasers. However, an experi-enced surgeon using a scalpel blade or electrocau-tery could produce superior results compared withan inexperienced surgeon using CO2 laser or radio-surgery. No amount of advanced technology canmake up for lack of training, surgical skill, or expe-rience.

Research and Peer-Reviewed Literature

There is a plethora of scientific reports, case reviews,and research studies that have looked at the effectsof an individual surgical device. However, there arevery few studies that have objectively and directlycompared laser and radiosurgery.

Incisional CharacteristicsStudies that have objectively assessed different surgi-cal modalities generally do so by comparison with agold standard that causes no collateral damage (e.g.,scalpel blade incision). Unlike electrocautery andlow-frequency electrosurgery, radiosurgery and CO2

laser offer superior accuracy and reduced collateraldamage. Histologic studies involving human skinpeel grafts concluded that radiosurgery producesless epidermal loss, reduced zone of thermal dam-age, and reduced dermal fibrosis than CO2 laser.7 Inother comparative studies including turbinate abla-tion and resection, biopsy collection, and effects onoviductal tissue, radiosurgery was comparable or su-perior to CO2 laser.8,9,14 In veterinary medicine, evenless has been published; however, a recent publica-tion in Veterinary Surgery described the collection ofskin biopsies from greyhounds using scalpel, skinbiopsy punch, monopolar electrosurgery, CO2 laser,and radiosurgery.13 This study found that collateraldamage and char associated with radiosurgery wassignificantly less than for CO2 laser, and concludedthat radiosurgery caused less lateral thermal damageto canine skin biopsies than CO2 laser. Studies at theUniversity of Georgia have compared the incisionalcharacteristics of radiosurgery and CO2 laser on theskin and muscle of pigeons and iguanid lizards. Inpigeon skin, radiosurgery caused less collateral ther-mal damage than CO2 laser (94 � 60 �m vs 150 � 64�m) (Fig 9).15 The results from iguanas were similar,with both radiosurgery and laser able to producebloodless incisions, but radiosurgery caused signifi-cantly less collateral tissue damage in skin (307 � 94�m vs 386 � 108 �m) and muscle (18 � 7 �m vs 91 �31 �m) compared with CO2 laser (Hernandez-Divers, unpublished data, 2006) (Fig 10). From theseveterinary studies, it appears that radiosurgery causes

significantly less collateral damage than CO2 laser.

ar �

172 Hernandez-Divers

Tissue Effects and HealingThere have been few veterinary studies to assess thehealing process after their use. The effects of Nd-YAG and CO2 laser tenotomies of flexor digitorumprofundus muscles in rabbits were used to evaluatethe effects of laser on collagen tissue.16 The mostconsistent observation was variable carbonization(charring) in most cases. Studies on the morpholog-ical consequences of thermosurgery and carboniza-tion in human tissue biopsies and rat organs havedemonstrated areas of necrosis, coagulation, andedema, with cellular granulation predominantly bygiant cells. Laser surgery on the buccal mucosa ofrats was performed to assess the effects on lymphaticvessels, and whether laser tumor resection may leadto iatrogenic metastases via the lymphatics.17 Thisstudy demonstrated that lymphatic vessels are absentfrom the area of carbonization, occluded by coagu-lation in the zone of necrosis, and dilated within thezone of edema. The authors concluded that laserresection of tumors was unlikely to result in lym-phatic spread. The regeneration of lymphatics wascorrelated to overall wound healing, being delayedwith laser (CO2 more so than Nd-YAG) comparedwith conventional scalpel surgery. Other studies

Figure 9. Comparison between CO2 laser (A) and 4.0-MHz radiosurnecrosis associated with the laser. Hematoxylin and eosin (stain), b

Figure 10. Comparisons between scalpel (A), radiosurgical (B), andcollateral damage in the scalpel incision and the greatest thickness

(stain), bar � 50 �m.

have confirmed this delayed primary intentionwound healing after laser surgery. This delay is pri-marily because of the temporary postponement ofinflammation, phagocytic resorption, collagen pro-duction, and re-epithelialization in the early stagesof repair.18

Various human studies involving radiosurgery de-vices, particularly in dermatologic and ophthalmo-logic surgery, have been published.19-25 These studieshave demonstrated the atraumatic and minimal col-lateral damage associated with radiosurgery. Tonsi-lectomy using radiosurgery has been shown to causeless pain and result in faster healing than traditionalsurgery in human pediatrics.24 In one study, radio-surgery was credited with reducing stump neuromasin the rat—a common complication of traditionalamputation techniques.25 In addition, veterinarytexts, especially those dealing with avian and otherexotic species, have advocated radiosurgery for anumber of years.5,26-28

Few studies have directly compared the functionaltissue effects and healing associated with laser andradiosurgery. One study compared radiosurgical andCO2 laser resection of nasal turbinates in humans,and concluded that although both methodologies

B) skin incisions in pigeons; note the greater thickness of collateral100 �m.

aser (C) muscle incisions in green iguanas; note the absence of anyollateral necrosis associated with the laser. Hematoxylin and eosin

gery (

CO2 lof c

Radiosurgery and Laser in Zoological Practice 173

were equally effective at accomplishing the surgicalgoals and resolving nasal obstruction, CO2 laser re-sulted in significantly greater disturbance of muco-ciliary function.29 Another comparative study involv-ing human oviducts revealed that radiosurgery wasthe least traumatic instrument used, with CO2 laserbeing second.8

Postoperative Pain and ComplicationsDespite the common proclamation that CO2 lasersresult in less postoperative pain, there have been fewobjective comparisons between radiosurgery and la-ser.30 However, 2 independent studies that evaluatedpain after soft palate resection in humans both con-cluded that radiosurgery produced less postopera-tive pain than CO2 laser.14,31 Typically, patients whounderwent radiosurgery had discomfort for 2.6 dayswith only 9% requiring narcotic analgesics, com-pared with patients who underwent laser treatmentwho experienced pain for an average of 13.8 daysand 100% required narcotic analgesics.31 Further-more, postoperative side effects (e.g., trouble withsmell and taste, pharyngeal dryness, globus sensa-tion, voice change, and pharyngonasal reflux) andcomplications (e.g., wound infection, dehiscence,posterior pillar narrowing) were more common afterCO2 laser surgery than those when radiosurgery was

Table 2. Comparison between 4Surgical device 4.0-MHz radiosurgeryEnergy provision Ultrahigh frequency radiowaveIncisions Minimal trauma using filter-cu

fiber electrodeCosts Less expensive ($4,300-$18,0Occupational Safety and

Health Administrationregulations

Minimal: evacuation of surgica

Available modes Monopolar (cutting, coagulatioBipolar

Ancillary equipment Large selection of wire electrofor soft tissue, dentistry, neuorthopedics, and endoscopic

Comments Excellent results possible withexperience

Versatile for traditional and ensurgery

Tissue contact � good tactile

used.14

Summary

Table 2 provides a comparative summary of CO2

laser and radiosurgery units. Laser and radiosurgeryusage is well established in veterinary medicine, andtheir list of surgical indications is certain to grow asthis technology becomes further used within prac-tice. In the future, those procedures already devel-oped in areas of human medicine, including oph-thalmology, gastroenterology, urology, neurology,and gynecology, will continue to filter into the vet-erinary profession. In an age when marketing hypecan sometimes overshadow science, it is wise to fullyinvestigate and personally evaluate equipment be-fore making a major capital investment. The latterpoint cannot be overstressed because individual sur-geon ability and preferences will undoubtedly havemore effect on surgical outcomes than the nature ofthe surgical device used.

References

1. Klause SE, Roberts SM: Lasers and veterinary sur-gery. Compend Contin Educ Pract Vet 12:1565-1576,1990

2. Polanyi TG: Physics of the surgical laser. Adv SurgOncol 1:205-215, 1978

Hz radiosurgery and CO2 laserCO2 laser

8-4.0 MHz LASER 10,600 nmmicro- Minimal trauma using focused beam and

small spot sizeMore expensive ($21,000-$33,500)

ors Significant: evacuation of surgical vapors,covered windows, protective glasses,and covering patients’ eyes to preventretinal damage

lgaration) Focused beamDefocused beam

and devicesrgery,ery

Limited number of hand pieces andceramic tips available from 0.25-1mm; a 2.7-mm cystoscope probe isavailable

ing and Excellent results possible with trainingand experience

opic Unable to use in fluid environments or inmost endoscopic applications

back No tissue contact � no tissue drag

.0-M

s, 3.t and

00)l vap

n, fu

desrosusurg

train

dosc

feed

3. Miller WW: Using high-frequency radio wave tech-

174 Hernandez-Divers

nology in veterinary surgery. Vet Med Small AnimClin 99:796-802, 2004

4. Ackerman LJ: Dermatologic applications of radio-wave surgery (radiosurgery). Compend Contin EducPract Vet 19:463-471, 1997

5. Altman RB: Radiosurgery. Semin Avian Exotic PetMed 9:180-183, 2000

6. Maness WL, Roeber FW, Clark RE, et al: Histologicevaluation of electrosurgery with varying frequencyand waveform. J Prosthet Dent 40:304-308, 1978

7. Acland KM, Calonje E, Seed PT, et al: A clinical andhistologic comparison of electrosurgical and carbondioxide laser peels. J Am Acad Dermatol 44:492-496,2001

8. Olivar AC, Forouhar FA, Gillies CG, et al: Transmis-sion electron microscopy: evaluation of damage inhuman oviducts caused by different surgical instru-ments. Ann Clin Lab Sci 29:281-285, 1999

9. Turner RJ, Cohen RA, Voet RL, et al: Analysis oftissue margins of cone biopsy specimens obtainedwith “cold knife,” CO2 and Nd:YAG lasers and aradiofrequency surgical unit. J Reprod Med 37:607-610, 1992

10. Administration OSH: OSHA Technical Manual. Sec-tion III: Chapter 6, Laser Hazards. Washington, DC,US Department of Labor, 2006

11. Plappert UG, Stocker B, Helbig R, et al: Laser pyrol-ysis products—genotoxic, clastogenic and mutageniceffects of the particulate aerosol fractions. Mutat Res441:29-41, 1999

12. Winstin C: The effects of smoke plume generatedduring laser and electrosurgical procedures. MinimInvasive Surg Nurs 8:99-102, 1994

13. Silverman EB, Read RW, Boyle CR, et al: Histologiccomparison of canine skin biopsies collected usingmonopolar electrosurgery, CO2 laser, radiowave ra-diosurgery, skin biopsy punch, and scalpel. Vet Surg36:50-56, 2007

14. Rombaux P, Hamoir M, Bertrand B, et al: Postop-erative pain and side effects after uvulopalatopha-ryngoplasty, laser-assisted uvulopalatoplasty, andradiofrequency tissue volume reduction in primarysnoring. Laryngoscope 113:2169-2173, 2003

15. Hernandez-Divers SJ, Stahl SJ, Cooper T: Compari-son between CO2 laser and 4.0 MHz radiosurgery forincising skin in white Carneau pigeons (Columbalivia). J Avian Med Surg, in press, 2008

16. Gebauer D, Constantinescu MA: Effect of surgicallaser on collagen-rich tissue [article in German].Handchir Mikrochir Plast Chir 32:38-43, 2000

17. Werner JA, Lippert BM, Schunke M, et al: Animal

experiment studies of laser effects on lymphatic ves-

sels. A contribution to the discussion of laser surgerysegmental resection of carcinomas [article inGerman]. Laryngorhinootologie 74:748-755, 1995

18. Hendrick DA, Meyers A: Wound healing after lasersurgery. Otolaryngol Clin North Am 28:969-986,1995

19. Lushkin AS, Berlev OB, Kalashnikov SA, et al: Fea-tures of radio wave tissue dissection in surgical prac-tice [article in Russian]. Vestn Khir Im I I Grek162:26-31, 2003

20. Hettinger DF: Soft tissue surgery using radiowavetechniques. J Am Podiatr Med Assoc 87:131-135,1997

21. Eisenmann D, Jacobi KW: Use of the Ellman Surgi-tron in eyelid and plastic surgery [article in Ger-man]. Ophthalmologe 91:540-542, 1994

22. Hurwitz JJ, Johnson D, Howarth D, et al: High-fre-quency radio wave electrosection of full-thicknesseyelid tissues. Can J Ophthalmol 28:28-31, 1993

23. Henry F: The value of a high-frequency bistoury inplastic surgery [article in French]. Ann Chir PlastEsthet 34:65-68, 1989

24. Hultcrantz E, Ericsson E: Pediatric tonsillotomy withthe radiofrequency technique: less morbidity andpain. Laryngoscope 114:871-877, 2004

25. Rahimi F, Muehleman C: Epineurial capping via Sur-gitron and the reduction of stump neuromas in therat. J Foot Surg 31:124-128, 1992

26. Bennett RA: Surgical considerations, in Ritchie BW,Harrison GJ, Harrison LR (eds): Avian Medicine:Principles and Application. Lake Worth, FL, WingersPublishing, 1994, pp 1081-1095

27. Bowles HL, Odberg E, Harrison GJ, et al: Surgicalresolution of soft tissue disorders, in Harrison GJ,Lightfoot TL (eds): Clinical Avian Medicine. Volume 2.Palm Beach, FL, Spix Publishing, Inc., pp 775-829, 2006

28. Hernandez-Divers SJ: Surgery: principles and tech-niques, in Raiti P, Girling S (eds): Manual of Rep-tiles. 2nd ed. Cheltenham, England, British SmallAnimal Veterinary Association, pp 147-167, 2004

29. Sapci T, Sahin B, Karavus A, et al: Comparison of theeffects of radiofrequency tissue ablation, CO2 laserablation, and partial turbinectomy applications onnasal mucociliary functions. Laryngoscope 113:514-519, 2003

30. Mader DR: Laser surgery for avian and exotic pets.Vet Pract News 17:26, 2005

31. Troell RJ, Powell NB, Riley RW, et al: Comparison ofpostoperative pain between laser-assisted uvulopala-toplasty, uvulopalatopharyngoplasty, and radiofre-quency volumetric tissue reduction of the palate.

Otolaryngol Head Neck Surg 122:402-409, 2000