Staged endoscopic ventricular foreign body removal in a gyr falcon (Falco rusticolus).
Article Type: Report
Subject: Endoscopic surgery (Usage)
Endoscopy (Usage)
Foreign bodies (Medical care) (Health aspects)
Heart diseases (Care and treatment)
Heart diseases (Research)
Author: Lloyd, Christopher
Pub Date: 12/01/2009
Publication: Name: Journal of Avian Medicine and Surgery Publisher: Association of Avian Veterinarians Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Association of Avian Veterinarians ISSN: 1082-6742
Issue: Date: Dec, 2009 Source Volume: 23 Source Issue: 4
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: United Arab Emirates Geographic Code: 7UNIT United Arab Emirates
Accession Number: 252007009
Full Text: Abstract: A large ventricular foreign body was identified on radiographs in a captive-bred gyr falcon (Falco rusticolus) that was presented for paresis and swollen abdomen. On endoscopic examination, a large shiny mass was visible in the ventriculus. An ingluviotomy was done, and pieces of the mass, which consisted of a ball of artificial grass fibers, were removed by using a rigid endoscope and grasping forceps. Subsequently, 4 more ingluviotomies were required to gain endoscopic access to the ventriculus and to allow staged removal of the mass in a piecemeal fashion. Feeding the falcon a feathered quail and allowing it to cast naturally removed the remaining fibers of the mass. No deleterious effects were observed in the bird.

Key words. ventricular foreign body, rigid endoscopy, ingluviotomy, avian, gyr falcon, Falco rusticolus

Clinical Report

An 8-year old, 1.1-kg, captive-bred, male gyr falcon (Falco rusticolus) was presented for left leg paresis of 48 hours' duration. The bird was housed in an artificially lit indoor flight pen, was eating well, and was showing no other clinical signs. The perches and floor were covered in artificial grass matting. The bird had been vaccinated against Newcastle disease with an inactivated poultry vaccine (Nobilis Newcavac, Intervet, Boxmeer, Holland) 6 months earlier and was fed a diet of skinned quail bred on-site from a closed flock.

Clinical examination with the falcon under isoflurane anesthesia administered by face mask revealed a swollen abdomen. A large, hard, immobile mass was palpable in the abdomen caudal to the sternal border. Lateral radiographs showed a 4.5 x 5.0-cm, laminated, partially radiodense mass in the ventriculus (Figs 1 and 2). The mass was closely associated dorsally with the renal silhouette and was displacing the intestines caudally and the liver cranially. A blood sample was taken from the right jugular vein and submitted for hematologic and plasma biochemical analysis. Results revealed a mild leukocytosis, at 10.9 x [10.sup.3] cells/[micro]L (reference range, 4.2-10.8 x [10.sup.3] cells/[micro]L), (1) with an absolute heterophilia, at 9.92 x 103 cells/[micro]L (reference range, 2.31 8.85 x [10.sup.3] cells/[micro]L). (1) Results of biochemical analysis showed high concentrations of uric acid, at 23.4 mg/dL (reference range, 1.3511.61 mg/dL) (2) and creatine kinase at 3267 IU/L (mean [SD] reference value, 402 [+ or -] 163 IU/L). (3) A 2.7-mm, 18-cm 30[degrees] Hopkins telescope (Karl Storz 64019A, Karl Storz Veterinary Endoscopy America Inc, Goleta, CA, USA) connected to a xenon light source by a fiber-optic cable was housed within a 14.5-Fr operating sheath (67065CV; Karl Storz), and a length of intravenous tubing was connected to the lateral port. The contralateral port and the instrument channel were closed. The endoscope was introduced into the crop through the oral cavity, and the crop was manually insufflated by the operator while the endoscope was passed through the thoracic esophagus into the proventriculus to the level of the isthmus. At the full working length of the endoscope, a shiny fibrous black mass fully occupying the ventriculus and stretching the isthmus was visible. A provisional diagnosis of a foreign body was made. The bird was scheduled for endoscopic exploration by ingluviotomy the next day and was given marbofloxacin (20 mg/kg IM q24h, Marbocyl 10%; Vetoquinol, Lure Cedex, France) before surgery.

[FIGURE 1 OMITTED]

The bird was premedicated with butorphanol (1 mg/kg IM, Torbugesic; Fort Dodge, Fort Dodge, IA, USA), and general anesthesia was induced by face mask with 5% isoflurane. The bird was intubated with an uncuffed 3.5-mm endotracheal tube and placed in dorsal recumbency on a heated table. The endotracheal tube was connected to an artificial ventilator (SAV-03; Vetronic Services, Devon, UK) and ventilated every 5 seconds with 2%-3% isoflurane in oxygen. The cardiac rate was constantly monitored with an electrocardiogram (CardioStore; Vetronic). Warmed 0.9% saline solution with 5% dextrose solution was given via an intravenous 25-gauge catheter placed in the ulnar vein as an initial bolus of 10 ml and then 5 ml every 30 minutes. The bird was prepared for surgery and draped at the level of the thoracic inlet. A cotton-tipped applicator was placed into the crop through the oral cavity and used to identify the location for an ingluviotomy incision. After a 3cm skin incision, stay sutures were placed in the crop wall and a crop incision roughly half the length of the skin incision was made. A 1-L bag of 0.9% saline solution warmed to 90[degrees]F was connected via an intravenous drip set to the lateral port of the 2.7-mm Hopkins telescope and operating sheath described above. The flow rate of the saline solution was controlled by the port on the examination sheath. The tubing from an intravenous drip set was then connected to the opposite port on the examination sheath in an attempt to accommodate any overflow of saline solution. The head of the falcon was kept below the ingluviotomy incision to prevent aspiration of infused saline solution. The endoscope was introduced into the crop, which then was insufflated with saline solution to allow visualization of the thoracic esophagus. The endoscope then was passed through the thoracic esophagus and into the proventriculus and ventriculus. A fibrous ball of tightly packed artificial fibers filled the entire ventriculus and was pressed tightly against the mucosal surface. A flexible 5F grasping forceps (67161T; Karl Storz) was passed down the instrument channel of the operating sheath to assess the mass. The density of the mass and the poor bite strength of the forceps prevented any sizeable amounts of fibrous material from being removed. A rigid grasping forceps (Richard Wolf GmBH, Knittlingen, Germany) with a locking ratchet mechanism was inserted through the ingluviotomy incision into the proventriculus alongside the endoscope. Pieces of fibrous material were removed from the ball by grasping and pulling small amounts from the main mass. The material was identified as plastic artificial grass matting. After 1 hour, the procedure was abandoned because of anesthetic duration, the fact that it was not possible to remove the entire mass at one session by using this method, and the repeated cranial traction placed on the mass was causing some mucosal damage to the isthmus. The ingluviotomy incision was closed with 2-0 polyglactin 910 (Vicryl; Johnson & Johnson, Sommerville, NJ, USA) on a round-bodied taper needle in a continuous inverting suture pattern. The skin incision was closed separately by using the same suture material in a simple interrupted suture pattern. The bird was sent home on marbofloxacin (20 mg/kg PO q24h for 5 days), and the owner was instructed to remove all possible sources of carpeting material from the enclosure and to feed quail with no casting material. The weight of the removed matting after 48 hours drying at 35[degrees]C was 0.49 g.

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

The bird was reexamined 3 days later and was reported to be standing on its left leg and perching normally. Anesthesia was induced as described above. A repeated lateral radiograph was taken, and the mass had reduced in size to 4.2 x 4.5 cm, with a noticeably increased distance between the kidney silhouette and the dorsal wall of the ventriculus. The surgery was repeated, as described above, through the same ingluviotomy incision. On this occasion, the procedure was again limited to 1 hour in duration for the reasons described above, and 0.65 g of material (dry weight) was removed. Radiographs and surgery were repeated 3 more times on days 15, 43, and 64, when 0.9 g, 2.3 g, and 2.9 g (dry weight), respectively, of carpet material were removed (Fig 3). On day 68, a lateral radiograph was repeated. The mass was now 2.5 x 2.5 cm (Fig 4). Results of a blood sample submitted for hematologic testing and plasma biochemical analysis were within reference ranges. Because the mass was small enough to cast, a feathered quail was offered on day 70 when the ingluviotomy incision had healed. The bird cast 1.5 g of plastic matting fiber 2 days after being offered feathered quail. Follow-up radiographs showed no foreign material in the ventriculus. No further problems have been reported by the owner.

Discussion

In this falcon, a ventricular foreign body that consisted of plastic matting was removed successfully by staged endoscopic removal assisted by natural casting material. Staged endoscopic removal of a large foreign body in birds has not previously been reported, and, for some cases, this technique may provide an alternative to ventriculotomy. The retrieval of the foreign body in this falcon could have been accomplished by either the method described or by ventriculotomy. The size of the mass prevented it from being cast naturally. Casting is a physiologic process in many birds of prey that clinicians can use to their advantage when trying to remove small foreign bodies from the proventriculus and ventriculus. (4) To cast naturally, the mass must physically be able to pass through the isthmus from the ventriculus to the proventriculus, into the crop, and lastly through the oral cavity. Despite strong, repeated cranial traction during piecemeal removal of this mass, pulling the mass through the isthmus into the proventriculus was not possible; therefore, the bird would not have cast it naturally. Although wire basket retrieval devices (67023 VK; Karl Storz) were used to remove carpeting material from similar-sized psittacine birds, (5) the size of this mass and the volume it occupied in the ventriculus

precluded use in this case, because the basket could not have enclosed the mass and would still have necessitated removing the mass through the isthmus. The operating sheath and integrated grasping forceps supplied for the 2.7-mm rigid endoscope did not have the bite strength to pull pieces of matting from the main mass in any substantial amount. A flexible endoscope may have allowed access to the mass through the oral cavity, but the delicacy of the forceps would have negated this advantage. Although ventriculotomy would likely have allowed removal of the foreign body in one surgical procedure, there are no reports on the success of ventriculotomy in raptors or on how the anatomy of the gastrointestinal tract in carnivorous birds may affect the procedure and prognosis compared with other species in which the procedure was described. (6-7) Most texts indicate that retrieval by endoscopic methods is preferable to ventriculotomy. (8)

[FIGURE 4 OMITTED]

Sealing ventriculotomy incisions with sutures can be difficult because the muscular wall may not hold sutures well, and muscular contraction of the ventriculus can lead to dehiscence, in addition, birds do not have an omentum that can adhere to damaged serosal surfaces and prevent small leaks. In this falcon, the foreign body would have to have been removed through a large ventriculotomy incision or broken up in situ and removed piece by piece through a smaller ventriculotomy incision.

The advantage of endoscopic removal is that no incisions of the body wall, air sacs, or ventriculus are required. In falcons up to 1.4 kg, the proventriculus can be visualized via the oral cavity by using an 18-cm telescope and air insufflation. However, access to the ventriculus via the oral cavity was not possible in this bird, thus necessitating an ingluviotomy as described for other species. (9) The ingluviotomy incision was relatively small, and repeated ingluviotomies appeared to cause no problems for this bird. The bird was fed quail meat without casting material after each procedure with no complications. After resolution of the initial paresis, the foreign body caused no clinical problems, so it was thought that the removal could be staged. Periods of up to 3 weeks were left between procedures to allow time for surgical wounds to heal.

A disadvantage of endoscopic removal is the restricted visualization of the entire ventriculus. The 18-cm telescope enabled visualization of the entire ventriculus in this falcon; however, in a larger bird, a longer rigid telescope or flexible endoscope would be required. Certain small foreign bodies among the stomach contents may be difficult to locate by endoscopy, or a suitable instrument may not be available to grasp the object, in which case, ventriculotomy is indicated. Speer (10) described the use of an endoscope through a proventricular incision to remove foreign material in a cockatoo; however, the singular, dense nature of the mass in this case precluded this method. A disadvantage of the procedure used in this case was that continued traction on the mass to remove fibers caused the bulk of the mass to rub against the isthmus. This caused some minor mucosal bleeding and was a limiting factor on the length of the procedure. After the second surgery, the mass became easier to break apart, presumably because the amount of matting remaining was such that it was not becoming tightly compressed by the muscular contractions of the ventriculus. As a result, larger amounts of material could be removed at each subsequent surgery.

Falcons harbor a large population of gramnegative bacteria in the gastrointestinal tract as normal commensal organisms. (11) In the correct environment, these bacteria may become opportunistic pathogens and often are a cause of ingluvitis and stomatitis. Enterobacter, Klebsiella, and Proteus species, and Escherichia coli are regularly isolated from healthy falcons presented to our hospital. This falcon had a compromised gastrointestinal tract before surgery and thus was at higher risk of gram-negative infection. For this reason and because the bird was a breeding bird that could not be caught for twice daily therapy, the bird was treated once daily with a fluoroquinolone antibiotic.

The first clinical sign observed in this bird was paresis, presumably because of pressure of the mass on the kidney and ischiatic nerve roots. The bird had been in the chamber with the carpet for 5 years. The bird was imprinted and trained to donate semen for artificial insemination; however, it was not accustomed to the "hat" collection technique used by this keeper and would try to mate with the keeper's leg. The bird subsequently became frustrated and would tear at the carpet in the room when the keeper left. It seems unusual that the falcon never cast after ingesting this foreign material; however, the diet offered did not contain any natural casting material. Once most of the plastic matting was removed by endoscopy, the bird was offered natural casting material and produced a pellet within 48 hours.

The approach to ventricular foreign bodies in birds is affected by the nature of the foreign body, the clinical signs, the species affected, the tools available, and the preference or experience of the veterinarian. In this case, the decision to manage the case by staged endoscopic removal proved to be a reasonable option and resulted in a favorable outcome for the bird.

References

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(2.) Lierz M. Plasma chemistry reference values for gyrfalcons (Falco rusticolus). Vet Rec. 2003;153: 182-183.

(3.) Altman RB, Clubb SL, Dorrestein GM, Quesenberry K. Avian Medicine and Surgery. Appendix I. Philadelphia, PA: WB Saunders; 1997:1020.

(4.) Cooper JE. Fits, incoordination and coma. In: Beynon PH, Forbes NA, Harcourt-Brown NH, eds. BSAV A Manual of Raptors, Pigeons and Waterfowl. Cheltenham, Gloucestershire, UK: British Small Animal Veterinary Association Ltd; 1996:197-207.

(5.) Hernandez-Divers S J, Blasier M, Wilson HG, Chrisian M. Endoscopic removal of (pro)ventricular foreign bodies in parrots. Proc Annu Conf Assoc Avian Vet. 2006:359-362.

(6.) Bailey TA, Kinne J, Naldo J, et al. Two cases of ventricular foreign bodies in the kori bustard (Ardeotis kori). Vet Rec. 2001;149:187-188.

(7.) Honnas CM, Blue-McLendon A, Zamos DT, et al. Proventriculotomy in ostriches: 18 cases (1990-1992). J Am Vet Med Assoc. 1993;202:1989-1992.

(8.) Bennett RA. Surgery of the avian gastrointestinal tract. Proc Atlantic Coast Vet Conf. 2002.

(9.) Murray M J, Taylor M. Retrieval of proventricular and ventricular foreign bodies with rigid endoscopy equipment. Proc Annu Conf Assoc Avian Vet. 1995:281-284.

(10.) Speer BL. Chronic partial proventricular obstruction caused by multiple gastrointestinal foreign bodies in a juvenile umbrella cockatoo (Cacatua alba). J Avian Med Surg. 1998;12:271-275.

(11.) Lloyd C. Raptors: gastrointestinal tract disease. In: Chitty J, Lierz M, eds. BSA VA Manual of Raptors, Pigeons and Passerine Birds. Quedgeley, Gloucestershire, UK: British Small Animal Veterinary Association Ltd; 2008:260-269.

Christopher Lloyd, BVSc, MSc, CertZooMed, MRCVS

From Nad Al Shiba Veterinary Hospital, PO Box 116345, Dubai, UAE.
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