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Procedures

( Stephen J. Divers BVetMed, DZooMed, Dipl ACZM, Dip ECZM (herpetology), FRCVS )

Diagnostic endoscopy has proven to be an important diagnostic tool for exotic animal veterinarians wishing to visualize and biopsy from internal structures; however, such procedures have concentrated on single-entry techniques. The evolution of multiple-entry endoscopic procedures has been developed at the University of Georgia from human pediatric laparoscopy. The addition of a second and third port using 2.5 or 3.5 mm cannulae has facilitated the use of 2 or 3 mm instruments within the avian or reptile body cavity. Triangulation of various instruments coupled with radiosurgical hemostasis has made several endoscopic procedures possible including gonadectomy and salpingohysterectomy. In addition, endoscope-assisted minimally-invasive procedures including enterotomy, enterectomy, cloacopexy, and pneumotomy may be initiated internally and completed using more established techniques. The majority of pet birds and reptiles are relatively small and delicate, and standard coeliotomy procedures cause greater morbidity and may not be well tolerated. The advent of minimally-invasive endoscopic surgery offers significant benefits including rapid and accurate diagnosis, reduced need for extensive coeliotomy, reduced surgical stress, improved pulmonary function, more stable anesthesia, and reduced surgical and hospitalization periods. Training in reptile and bird endosurgery is available through the continuing education service of the College of Veterinary Medicine.


Single-Entry Techniques

Single-entry endosurgery is limited to a single instrument that cannot be manipulated independently of the telescope. Salpingohysterectomy in juvenile cockatiels has been accomplished using the 2.7 mm telescope, 14.5 Fr sheath and grasping forceps to break down the suspensory ligaments and remove the infundibulum, oviduct, and uterus. Air sac granulomas have been successfully removed using a combination of endoscopic debridement and diode laser ablation in several parrots.


Endoscopic debridement of airsac granulomas from a parrot. Left - before surgery showing the intact granuloma. Right - after endosurgical debridement and laser ablation.


Double-Entry Techniques

An additional operating port enables the endoscopist to utilize a second instrument independently of the telescope. Salpingohysterectomy and gonadectomy can be performed using by two-entry technique. Grasping forceps placed via the sheath can be used to elevate the testis, while monopolar scissors are used to dissect the testis free from the mesorchium. Alternatively, a polypectomy snare can be inserted and slid over the testis. Double-entry techniques can also facilitate endoscope-assisted coelomic procedures. The telescope is used to identify the specific structure or organ of interest. Small hemostats are pressed against the coelom until the most appropriate coeliotomy site is identified using the telescope. A small, targeted coeliotomy incision directly over the structure of interest is made using a scalpel followed by blunt dissection into the coelom using hemostats. Endoscope-guided forceps can be used to exteriorize the structure, or minor procedures may be accomplished internally by using the endoscope to provide focal illumination and magnification. Examples would include biopsy, enterotomy, enterectomy, duodenostomy tube placement, cloacopexy, syringeal surgery, pneumonectomy, and gastrotomy. Such minimally-invasive procedures would decrease surgical trauma compared to standard coeliotomy.


Diagnostic coelioscopy through the prefemoral fossa of an adult Aldabra tortoise (Aldabrachelys gigantea). (A) inserting an endotip cannula under telescope guidance; (B) placement of two 6 mm endotip cannulae into the prefemoral fossa for telescope and instrument insertion; (C) examination of the insufflated coelom (oviduct on monitor) using a 5 mm 30o telescope.



Endoscopic castration in a pigeon using a double entry technique. Left - the polypectomy snare is placed over the testis to encircle the mesorchidium. Right - Following radiosurgical activation the testis is removed via the port hole.


Triple-Entry Technique

The most complicated but versatile techniques involve the use of 3 ports. The primary endoscopist controls both instruments and the foot-pedal activated radiosurgery device, while the telescope is maintained in position by support sandbags or an assistant. All of the procedures previously described can be more easily accomplished in larger birds using a triple-entry technique. Endosurgery is generally easier to perform as the structures can be handled and manipulated using two independent instruments without adversely affecting telescope position and hence the surgical field of view. The ability to employ two independent instruments makes endosurgery a practical alternative to more extensive standard coeliotomy procedures.


Operating room set-up for multiple-entry minimally-invasive endoscopic orchidectomy in a green iguana. Note that the endoscopist controls both instruments and an assistant supports the camera-endoscope unit.



Multiple-entry minimally-invasive endosurgery being performed in a green iguana. Note the two instruments that are entering the coelom via ports either side of the telescope to permit instrument triangulation.



Male green iguana undergoing endoscopic orchidectomy; a) The grasping forceps (F) are used to grasp the ventral edge of the testis (T) as it lies adjacent to the epididymis (E); b) The testis (T) is elevated revealing the testicular ligament (L) and associated blood vessels, the adrenal gland (A), and the renal vein (V); c) Scissors with monopolar radiosurgery are used to dissect the testis free, d) The testis is removed through the trocar hole. Note the lack of bleeding from the surgical site.



Patient positioning and technique for triple-entry avian endosurgery. (A) The bird is positioned in lateral recumbency with the pelvic limb held craniad to expose the flank; (B) Close-up of the surgical site demonstrating the sheathed telescope behind the last rib (port 1), the first cannula behind the pubis (port 2), and the second cannula through the last intercostal space (port 3).



Endoscopic salpingohysterectomy in a bird. Left - grasping forceps are used to elevate the oviduct and uterus, while monopolar scissors dissect the tract free close to the cloacal insertion. Right - View following endosurgery, note the complete absence of the oviduct and uterus.



Endoscopy in a Gulf sturgeon using a 5 mm telescope via ventral midline cannula 1. Instrument cannulae 2 and 3 are also in place.



Endoscopic gonadectomy in a Gulf sturgeon;
a) Babcock forceps (B) elevating the ovary (O) away from the dorsolateral peritoneum (P) to reveal the mesovarium (M). Forceps (F) have penetrated the mesovarium to begin dissection;
b) Bipolar radiosurgery forceps (R) dissecting through the mesorchium, between the testis (T) and peritoneum (P);
c) Caudal attachment of the gonad resected by bipolar radiosurgery forceps revealing the surface of the caudal kidney (K);
d) Testis (T) held by Babcock forceps (B) as the bipolar radiosurgery forceps (R) dissect craniad between the testis and the dorsolateral peritoneum;
e) Cranial attachment of the gonad after gonadectomy illustrating the proximity of the cranial endocrine kidney (K) just below the peritoneum (P). The liver (L) is also visible; f) A complete testis, approx 25 cm in length, removed by endoscopy.


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