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Paper Single surgeon coelioscopic orchiectomy of desert tortoises (Gopherus agassizii) for population management L. M. Proença, S. Fowler, S. Kleine, J. Quandt, C. O. Mullen, S. J. Divers Orchiectomy in chelonians is a challenging procedure, especially in large species with deep and elongated testes and extensive mesorchial attachments. Single surgeon coelioscopic orchiectomy was performed in seven adult desert tortoises (Gopherus agassizii), maintained at the Desert Tortoise Conservation Center (DTCC) in Las Vegas, for population management. Surgery was successfully conducted through a bilateral prefemoral approach via sequential vascular clip ligation and radiosurgery (monopolar/bipolar). Bipolar endoscopic forceps were considered indispensable due to the extensive mesorchial attachments and their close association with the kidney. A mechanical arm was effectively used to permit orchiectomy to be completed by a single surgeon. Six of seven animals recovered from anaesthesia. Necropsy demonstrated that the death of the other was unrelated to surgical complications. One animal experienced surgically significant haemorrhage, but still made a clinical recovery. The six tortoises were returned to the DTCC and, six months postoperatively, remain healthy. This small study suggests this minimally invasive technique is an effective method for bilateral orchiectomy in desert tortoises and might be preferable in large chelonians with elongated testes.
Introduction
The desert tortoise (Gopherus agassizii) occurs over large portions of the Mojave and Sonoran Deserts in the southwestern USA and northwestern Mexico. It was designated as threatened under the US Endangered Species Act 1973. Abandoned and relinquished ‘pet’ tortoises, uncontrolled backyard breeding of ‘pets’ and displacement from urban development have resulted in thousands of animals received by the Desert Tortoise Conservation Center (DTCC) in Las Vegas, Nevada. While most of Nevada desert tortoises are experimentally relocated to appropriate and controlled habitat within the state, an urgent solution to this critical problem is required. This paper reports a study to evaluate endosurgical sterilisation in this species with the goal of decreasing backyard reproduction. Orchiectomy in chelonians is a challenging procedure since the testes are located in the dorsocaudal coelomic cavity, intimately associated with the kidney, below the carapace. The mesorchium of chelonians is short and tight, such that the testes cannot be exteriorised from Veterinary Record (2014) L. M. Proença, DVM, MSc, PhD, S. Kleine, DVM, J. Quandt, DVM, MS, DACVAA, DACVECC, S. J. Divers, BVetMed, DZooMed, DACZM, DECZM, FRCVS, Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Drive, Athens, GA 30602, USA S. Fowler, DVM,
doi: 10.1136/vr.102421 C. O. Mullen, PhD, U.S. Fish and Wildlife Service, Desert Tortoise Recovery Office, 777 E. Tahquitz Canyon Way, Suite 208, Palm Springs, CA 92262, USA E-mail for correspondence: [email protected], cc: [email protected] Provenance: not commissioned; externally peer reviewed Accepted June 20, 2014
the coelom (O’Malley 2005, Innis and others 2013). Other sterilisation techniques such as phallectomy, orchiectomy via plastron osteotomy or prefemoral orchiectomies without coelioscopy have been performed in male chelonians, but all have disadvantages (Lawson and Garstka 1985, Licht and others 1985, Rivera and others 2011, Innis and others 2013). In contrast, prefemoral orchiectomy with the aid of coelioscopy offers a minimally invasive approach and has been shown to be effective, safe and appears to be a preferable method for sterilisation of male freshwater turtles because of improved surgical visualisation and accessibility, combined with shorter healing and recovery times (Innis and others 2013). The previously reported coelioscopic orchiectomy technique was accomplished by a single vascular clip or monopolar radiosurgery across a short mesorchium (Innis and others 2013). Different species have variable testicular anatomy, as well as seasonal and age-related testicular variations (Innis and others 2013). Consequently, the removal of larger testes in larger species would be more problematic, requiring additional internal dissection. For example, an attempt at coelioscopic orchiectomy of a hybrid Galapagos t ortoise (Geochelone nigra) was reported to have failed (Rivera and others 2011). The purpose of this study was to develop a feasible and effective method of endoscopic orchiectomy to be used in larger species, using the desert tortoise as a model. We describe an endosurgical technique that utilises a mechanical arm to permit orchiectomy to be completed by a single surgeon in chelonians with elongated testes.
Material and methods Animals
A group of seven adult male desert tortoises (G. agassizii) maintained at the US Fish and Wildlife Service and the DTCC in Las Vegas were used in a prospective study approved by the Animal Care and Use Committee (IACUC Number A2010 11-549-Y3-A1). October 25, 2014 | Veterinary Record
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Paper The tortoises were transported to the University of Georgia (UGA) and temporarily maintained in conditions approved by the Association for Assessment and Accreditation of Laboratory Animal Care. Each tortoise was physically examined and weighed on the day of arrival. Unique numbers were used to identify each individual. Upon arrival, blood was collected from a jugular vein with blood submitted in lithium heparin for packed cell volume (PCV) and total solids (TS).
Anaesthesia
The tortoises were simultaneously participating in a parallel anaesthesia study with specific anaesthesia data to be published separately. The animals were fasted for 48–72 hours prior to anaesthesia, although access to water was maintained. They were bathed in shallow, lukewarm water for two hours prior to the procedure to stimulate urination. Manual stimulation of the cloaca was also performed to promote bladder emptying before anaesthetic induction. Oxytetracycline (Liquamycin LA200, Pfizer) (5 mg/kg intramuscular) and meloxicam (Metacam, Boehringer Ingelheim) (0.2 mg/kg subcutaneous) were administered preoperatively (12–24 hours prior to surgery). The animals were physically restrained and induction was achieved using a combination of ketamine (Ketaset, Fort Dodge) (10 mg/kg) and dexmedetomidine (Dexdomitor, Pfizer) (50 µg/kg) administered intravenously into a jugular vein. Following induction, each animal was placed in a vertical (head up) position with pressure on the site of injection to reduce haematoma formation. The tortoises were randomly assigned to receive either a combination of lidocaine (2 mg/kg, lidocaine HCl 4 per cent, Hospira) and morphine (0.1 mg/kg, morphine sulfate, Hospira) or an equivalent volume of saline control intrathecally after induction. Jugular vein catheterisation was attempted in all animals using a 24 G intravenous catheter. If successful, 3 ml/kg/hour of lactated ringers solution (LRS) was administered intravenously. If unsuccessful, one dose of 25 ml/kg of LRS was administered subcutaneously. Each animal was intubated using an appropriately sized uncuffed endotracheal tube secured using a plastic mouth gag (FMG100, Plastic mouth gag, PetAg) and taped in position. The animals were maintained on 100 per cent oxygen for the duration of the procedure. Each tortoise was ventilated using a positive-pressure ventilator (Small animal ventilator VT-5000, BAS Vetronics, Bioanalytical Systems) at two breaths per minute and at a peak inspiratory pressure of 4–10 cm H2O. If additional anaesthesia was required, isoflurane was administered in oxygen and adjusted to patient requirements. Pulse was monitored with a Doppler ultrasonic flow detector (model 811-B; Parks Medical Electronics) placed over the carotid
Kidney
artery. A multiparametric monitor (LW6000 Multiparametric monitor, Digicare Biomedical Technology) was used to monitor end-tidal capnography (ETCO2), oesophageal temperature and ECG.
Endoscopic equipment and sterilisation
A 2.7 mm (wide view), 30°, 18 cm telescope (64019BA, Karl Storz, Tuttlingen, BW, Germany), endoscopic camera (22220055-3, Karl Storz), xenon light source (20132101-1, Karl Storz), imaging capture system (22201011U110, Karl Storz), mechanical holding arm (MHA) for the telescope (28272RKBKS, Karl Storz) and 3 mm endoscopic instrumentation were used (Karl Storz). Two monitors were connected to the camera to permit coelioscopy from either side of the table, and avoid moving the endoscopy tower if a bilateral coelioscopic procedure was required.
Prefemoral coeliotomy
Each tortoise was placed onto a heated surgery table (GMRTP22E, Heated water mattress, Gaymar Industries) maintained at 28–30°C. Each animal was positioned in right lateral recumbency using a vacuum bean bag positioner (SN103526, Natus, Planegg, Germany). Additional elevation of the head above the horizontal was undertaken to reduce the cranial movement of intrathecal medication. The hindlimbs were extended caudad and taped together to allow exposure of both prefemoral fossae. The left prefemoral fossa and surrounding shell were aseptically prepared and draped using standard techniques. A 5–6 cm craniocaudal skin incision was made in the cranial prefemoral fossa using a #15 scalpel blade. The subcutaneous tissues were bluntly dissected and the aponeurosis of the tendinosis parts of the ventral and oblique abdominal muscles identified and incised exposing the coelomic membrane. A 3 mm incision was made in the coelomic membrane to permit insertion of the telescope and confirmation of correct coeliotomy approach. The coelomic membrane incision was carefully extended, taking care not to damage the often voluminous and closely associated bladder, the septum horizontale (postpulmonary septum) or lung. A ring and elastic stay retractor (Lone star retractor, Cooper Surgical) was positioned to provide improved exposure of the coelom. The use of a single prefemoral coeliotomy incision permitted the use of multiple instruments without the need for additional cannulae.
Endoscopic orchiectomy
Following prefemoral coeliotomy, endoscopic examination of the coelomic cavity and identification of the left testis (Figs 1 and 3a), the
Testis
Lung
Large intestine
Colon Cloaca
Liver
Gall bladder Bladder
Small intestine
c 2013 UGA
FIG 1: Regional anatomy and instrument position during prefemoral coelioscopic orchiectomy of a male desert tortoise (Gopherus agassizii) in right lateral recumbency. Courtesy of Kip Carter, University of Georgia
Veterinary Record | October 25, 2014
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Paper
FIG 2: Mechanical holding arm (MHA) telescope orientation during prefemoral coelioscopic orchiectomy of a male desert tortoise (Gopherus agassizii). The optimal position of the MHA telescope was achieved when the telescope was positioned perpendicular to the table in the mid-dorsal region of the incision. A ring and elastic stay retractor was used to provide improved exposure of the coelom. Courtesy of Kip Carter, University of Georgia
MHA was used to secure the telescope in place. The MHA telescope was positioned to allow triangulation of the endosurgery equipment and optimal visualisation of the endosurgical field. Following correct positioning of the MHA telescope (Fig 2), the testis was grasped at the caudal aspect using 3 mm atraumatic endoscopic forceps with ratchet handle (303530N, Karl Storz), inserted alongside the telescope. The left (non-dominant) hand of the surgeon was used to secure and elevate the testis to expose the mesorchium and associated blood vessels (Fig 3b). The surgeon’s right (dominant) hand was used to manipulate 3 mm short curved Metzenbaum endoscopic scissors (30310MSS, Karl Storz) (Fig 3d), connected to a monopolar radiosurgery unit (Surgitron 4.0 MHz, Ellman International), 3 mm bipolar endoscopic forceps (26184HCS, Karl Storz) (Fig 3c), or medium to large stainless steel vascular clips (LT400 Vascular clips, Ethicon Endosurgery; 523600 Hemoclips, Teleflex) (Fig 3e) with curved or straight applicators. A combination of these instruments was used to dissect the testis free from its mesorchial attachments, paying careful attention to haemostasis. As the mesorchial transection proceeded in a caudal to cranial direction, the grip on the testis was adjusted to permit better exposure of the remaining mesorchium. After complete removal of the left testis, the coelomic cavity was inspected to verify haemostasis (Fig 3f). Visualisation of the contralateral (right) testis, through the left prefemoral approach, was attempted. If not possible, a bilateral procedure was elected. The left prefemoral coeliotomy was closed in a routine manner. Absorbable suture, poliglecaprone 25 (Monocryl-Plus; Ethicon) 3–0, on a tapered needle in a simple continuous pattern was used to close the coelomic aponeurosis and associated subcutaneous tissues in a single layer. The skin was closed using 3–0 poliglecaprone 25 on a cutting needle using a simple horizontal mattress pattern. If the right testis was not removed, the procedure was repeated via the right prefemoral fossa to remove the second testis. An adapted published scoring scale (Divers and others 2010) was used on this study. The ease of gonad visualisation was scored from 0 to 3 (0, no manipulation required; 1, minor manipulation; 2, major manipulation; and 3, impossible) for right and left testes. Ease of visualisation of the right gonad through a left prefemoral approach was scored from 0 to 3 (0, no manipulation required; 1, minor manipulation; 2, major manipulation; and 3, impossible). Ease of resection of both testes (right and left) was scored from 0 to 3 (0, simple; 1, minor
difficulty; 2 major difficulty; 3, impossible). Coeliotomy time (from start of the prefemoral incision to time of telescope entry) for the left and right side was individually recorded. Total surgery time (from start of the left prefemoral incision to the end of last suture on the right prefemoral fossa), left approach surgery time (from start of the left prefemoral incision to the end of last suture on the left prefemoral fossa) and right approach surgery time (from start of the right prefemoral incision to the end of last suture on the right prefemoral fossa) were accessed and recorded. All surgeries were performed by either one of two authors (Proença and Divers).
Postoperative care
All tortoises received postoperative hydromorphone (West-Ward) (0.5 mg/kg intramuscular) for pain management. If present, the intravenous catheter was removed once recovered and ambulatory. The animals were kept in recovery holding pens, without substrate, food or water, for the first 12–24 hours, until fully recovered. Each animal was given additional doses of oxytetracycline (5 mg/kg, intramuscular) and meloxicam (0.2 mg/kg, subcutaneous) daily for three days. Incisions were inspected daily for the duration of their hospitalisation at UGA (6–16 days postsurgery). Postoperative weights, PCV and TS were performed before discharge.
Results
Mean preoperative weight of the seven animals was 7.02 kg (range 5.94–8.36 kg). Results of preoperative physical examination revealed no abnormalities, except for animal number seven, which presented a scar on the left prefemoral fossa that may have been associated with a previous surgery. Preoperative results for PCV and TS were within the normal limits, with a mean of 26 per cent (range 24–29 per cent) and 35 g/l (range 29–40 g/l), respectively. No tortoises voided urine despite manual attempts to empty the bladder, but a few animals may have urinated during the bath in lukewarm water as faecal material was observed in the water. Despite unremarkable preoperative physical examinations, significant abnormalities were observed during coelioscopy of animals two, three and seven. Animal number two exhibited pale serosa of coelomic organs and what appeared to be vasoconstricted blood vessels, with an almost imperceptive pulse in coelomic arteries. Animal number three exhibited evidence of severe liver disease, and animal October 25, 2014 | Veterinary Record
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Paper
FIG 3: Coelioscopic orchiectomy of a male desert tortoise (Gopherus agassizii) via sequential vascular clip ligation and radiosurgical dissection. (a) Telescope view of the caudal coelom via a left prefemoral approach. (b) Atraumatic endoscopic forceps (F) used to expose the mesorchium and associated vasculature (arrow). (c) Stainless steel vascular clip (arrow) has been placed on the caudal aspect of the mesorchium, close to the kidney, prior to mesorchial coagulation using bipolar forceps (B). (d) Mesorchial dissection using short curved Metzenbaum scissors (S). (e) Placement of vascular clip (arrow) across the cranial aspect of the mesorchium. (f) View of the ligation clips (arrows) across the mesorchium remnant following excision of the testis. L, Lung; K, kidney; T, testis; C, colon; M, mesorchium
number seven had a large abscess in the left caudal lobe of the liver causing adhesion of the liver to the body wall. The surgical scores and times are summarised in Table 1. The ease of gonad visualisation for both right and left testes was consistently excellent (score 0), when approached through their respective sides. Ease of visualisation of the right gonad through the initial left prefemoral approach was never possible (score 3), and a bilateral approach was invariably required for all seven animals. Ease of testicular resection varied from simple (0) to major difficulty (2), but was successfully completed in all cases. The epididymis was not removed. The mean score for surgical ease was 0.85 for the right testis and 0.42 for the left testis (ie, between simple (0) and minor difficulty (1)). Left and right coeliotomy times were five and four minutes on average, respectively. Total surgery time was 154 minutes on average, with a mean of 82 minutes for left side and 72 minutes for the right side. The dark brown and smooth testes, approximately 6–8 cm in length and 0.5–1.5 cm wide, were tubular with tapering ends, and extended from the deep pelvic region medially towards the bridge of the shell laterally. The mesorchium was short with the caudal two-thirds closely attached to the ventral surface of the kidney. The epididymis was easily identified attached to the mid to caudal extent Veterinary Record | October 25, 2014
of the testis, and closely associated with the ventral aspect of the kidney. Bilateral orchiectomy was achieved via sequential vascular clip ligation and radiosurgery (monopolar and bipolar) starting at the caudal pole of the testis, and progressing craniad. Vascular clips were applied when large blood vessels were encountered, especially at the caudal, middle and cranial aspects of the mesorchium. Vascular clips were applied as close to the kidney as possible, and the mesorchium transected distal to the clip as close as possible to the testis. Special care was taken not to leave any testicular tissue behind (Fig 3). The size of the clips and shape of the applicator (curved or straight) were chosen based on the size of the vessel and position of the testis in relation to the incision, respectively. Bipolar endoscopic forceps were used when large vessels were not present and the space between the testis and kidney was considered too small for the use of monopolar scissors that create greater collateral tissue damage (Fig 3c). Following the use of the bipolar forceps, the 3 mm Metzenbaum endoscopic scissors were used to transect the cauterised mesorchium. Where there was sufficient space between kidney and testis, the Metzenbaum endoscopic scissors were used as a monopolar device to both effect haemostasis and transection of
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Paper TABLE 1: Endoscopy scores and surgery times for coelioscopic orchiectomy in seven desert tortoises (Gopherus agassizii)
Animal number
Ease of gonad visualisation right testis (right approach)*
1 2 3 4 5 6 7 Mean sd
0 0 0 0 0 0 0 0 0
Ease of gonad visualisation left testis (left approach)* 0 0 0 0 0 0 0 0 0
Ease of gonad visualisation right testis (left approach)* 3 3 3 3 3 3 3 3 0
Ease of resection of the right testis†
Ease of resection of the left testis†
0 0 2 1 1 2 0 0.85 0.89
0 0 1 0 1 0 1 0.42 0.53
Total surgery time (minutes) 128 117 187 114 174 183 179 154 33
Right approach surgery time (minutes) 68 40 94 56 80 100 69 72 20
Left approach surgery time (minutes) 60 77 93 58 94 83 110 82 18
Right coeliotomy time (minutes)
Left coeliotomy time (minutes)
2 2 11 3 3 5 3 4.14 3.18
3 6 1 19 3 2 3 5.28 6.23
*From 0 to 3 (0, no manipulation required; 1, minor manipulation; 2, major manipulation; and 3, impossible) †From 0 to 3 (0, simple; 1, minor difficulty; 2, major difficulty; 3, impossible)
the mesorchium (Fig 3d). Greater care was required to allow current to be applied only to the mesorchium without touching the kidney or other surrounding tissues. The radiosurgery unit was set to cut/ coagulation with power settings varied from 10 to 45 digital units or approximately 15–45 W. Particular care was taken to retract the testis away from the adjacent colon, lung, urinary bladder, kidneys and adrenal gland during dissection of the mesorchium. Correct positioning of the MHA telescope was essential to provide the best view and promote triangulation of the instruments. The optimal MHA telescope orientation was achieved when the telescope was positioned perpendicular to the table, in the mid-dorsal region of the incision (Fig 2). As the mesorchial transection proceeded in a caudal to cranial direction, the position of the MHA telescope was adjusted to permit closer view of the surgical site. All animals recovered from anaesthesia, with the exception of number two. Necropsy of this tortoise revealed hepatic lipidosis (diffuse, moderate to severe) and a large 5 cm×2 cm haematoma associated with the jugular vein (consistent with vein cannulation). No evidence of surgical complications was observed and the death was considered related to anaesthesia and pre-existing disease. Profuse haemorrhage occurred during resection of the right testis of number six. The haemorrhage occurred during final resection of the cranial aspect of the mesorchium, closely associated with the kidney, after the last vascular clip placement. Attempts were made to promote haemostasis using pressure (with sterile cotton tip applicators) and radiosurgery, and a partial reduction in bleeding was achieved. The animal’s coelom was copiously flushed with warm sterile saline before closure, with the animal monitored closely during the following 24 hours. Postoperative PCV and TS were decreased from 26 to 18 per cent and from 38 to 25 g/l, respectively. All remaining animals were observed eating the day following surgery. Mean postoperative PCV and TS were 25 per cent (range 18–30 per cent) and 27 g/l (range 25–32 g/l), respectively. There was no significant weight loss, postoperatively (mean weight 6.9 kg, range 6.12–8.74 kg). The six tortoises were returned to the DTCC and, six months postoperatively, remain healthy.
Discussion
Surgical sterilisation of male chelonians is not commonly performed. An effective technique of neutering red-eared terrapins (Trachemys scripta elegans) without the use of coelioscopy has been previously described (Kinney and others 2011). However, this method relies on the ability of the surgeon to visualise and manipulate the gonad through a small incision, using the unaided eye. The magnification and optimal visualisation provided by coelioscopy seems to be preferable in small species, such as red-eared terrapins, and essential in larger chelonians, such as Amazon River turtle (Podocnemis unifilis), but objective comparison requires future controlled studies (Innis and others 2013). In the authors’ opinion, orchiectomy without coelioscopy in larger species, such as the desert tortoise with longer and deeper testes, is not possible. Exteriorisation of the testicle is not feasible due to the short mesorchium attachment; therefore,
complete visualisation of the entire testicle is not achievable with the unaided eye, especially the cranial aspect, where the testicle is closely associated with the kidney and a large blood vessel is present and need to be properly ligated/coagulated. Endoscopic orchiectomy techniques have been described for three different species of chelonians: red-eared terrapin, Amazon River turtle and painted turtle (Chrysems picta picta). For smaller species, redeared terrapin and painted turtle (mean weight of 436 g), orchiectomy was conducted with a unilateral technique using a single vascular clip and/or radiosurgical transection of the mesorchium, requiring no major dissection. It is important to appreciate that, similar to the orchiectomy without coelioscopy, this method was only possible because of the small size and spherical shape of the testis (Innis and others 2013). By contrast, the procedure in the Amazon River turtle was protracted and more difficult, requiring a bilateral approach due to the different anatomy of the gonads (Innis and others 2013). The mean score for surgical excision of both testes was similar, between simple to minor difficulty. The slightly higher mean score for the right side was partially due to complications associated with tortoise number six. Visualisation on the contralateral testis through the left prefemoral approach was not possible in any animal. It is unclear if the ability of the surgeon, location of testes or a combination of factors could be responsible. Nevertheless, even if visualisation of the contralateral testis were possible, resection of both gonads via a unilateral approach would be more difficult. Mean surgery times for left and right orchiectomies were similar, 82 and 72 minutes, respectively. Mean total surgery time was 154 minutes, which was longer than that reported using similar techniques in other species, probably attributable to the longer testes of the desert tortoise (Innis and others 2013). These differences are probably compared with the red-eared terrapin (0.5–1 cm) and Amazon River turtle (4–5 cm) (Innis and others 2013). In this study, bilateral orchiectomy was achieved via sequential vascular clip ligation and radiosurgery (monopolar/bipolar). Although bipolar endoscopic forceps were not described in previous publications, they were considered indispensable for desert tortoise orchiectomy. Bipolar instruments resemble surgical forceps, with both the active electrode and the return electrode functions being performed at the surgical site, and confined only to the tissue between the forceps. Consequently, bipolar energy delivery reduces the chances of collateral damage to closely associated tissues, even if one electrode is touching an adjacent tissue. Contrarily, monopolar instruments offer a greater risk of collateral tissue damage, since the energy delivered by the instrument needs to travel through the animal and back to the generator through a conductive grounding pad placed under the patient (Massarweh and others 2006), and therefore any tissue inadvertently touched would be affected. In the desert tortoise, the mesorchial attachments are extensive and closely associated with the kidney. In these areas, bipolar radio surgery offers considerable advantages by avoiding collateral damage to the kidney and closely associated vasculature. The use of monopolar scissors is certainly possible and encouraged where the mesorchium width is larger, and enough space October 25, 2014 | Veterinary Record
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Paper exists between the instrument and adjacent kidney. The authors do not advise performing orchiectomy in mid to large chelonians without having bipolar endoscopic forceps available. In addition, a variety of vascular clip sizes and applicators are also useful and recommended. Contrary to previous reports, no complications (eg, perforation of the urinary bladder and inadvertent entry into the retrocoelomic space) were observed during coeliotomy (Innis and others 2013). The larger size of desert tortoises may have helped reduce these surgical complications. Although attempted, cloacal stimulation to encourage urination was not successful, and full urinary bladders were often observed upon entry. If concerns regarding large bladders exist, then ultrasound-guided cystocentesis or percloaca urethral catheterisation via cloacoscopic guidance could be considered. Number six was the only animal that endured surgical complications. Profuse haemorrhage occurred during final dissection of caudal aspect of the right mesorchium. Analysis of the endosurgery video suggested that telescope positioning was less than ideal and too far away from the surgical site. Therefore, a blood vessel, closely associated with the kidney, was not fully appreciated during vascular clip placement and only partial ligation was achieved. Despite significant blood loss, anaesthesia recovery was unremarkable and the animal demonstrated no clinical disadvantage. Number two did not recover from anaesthesia and necropsy demonstrated that death was unrelated to surgery or haemorrhage. However, a large haematoma, associated with the jugular vein, was found at necropsy, and demonstrates that a head-up position and local pressure may not prevent bleeding following venipuncture. Despite unremarkable preoperative physical examinations, significant abnormalities were observed during coelioscopy in three of the seven animals, which could complicate anaesthetic and surgical outcomes and should always be taken into consideration before submitting the patient through a surgical procedure. Due to the small number of tortoises used in the present research, further studies involving a larger number of animals are needed to assess the safety of coelioscopic orchiectomy in medium to large size tortoises. The use of antibiotics for routine sterilisation is controversial because of the possibility of causing antibacterial drug resistance. In this study, we started oxytetracycline preoperatively and repeated dosing for three days postoperatively at a dose of 5 mg/kg. To the authors’ knowledge, there is no pharmacokinetically derived oxytetracyline dose available for tortoises; however, pharmacokinetically derived doses of 10 mg/kg every five days in American alligators (Alligator mississippiensis) or of 25 mg/kg every 61 hours in sea turtles (Caretta caretta) may have been more appropriate (Harms and others 2004, Helmick and others 2004). Since the testes in chelonians are located in the dorsocaudal coelomic cavity, below the carapace, it is imperative that the telescope is equipped with a 30° angle to allow visualisation of the gonad. In the authors’ experience, the length of the telescope is not significant since inserting the instrument more than only few centimetres in the coelom caused instrument stumping (Fig 2). The 2.7 mm telescope is likely to be suitable for the procedure in larger chelonians, as long as a xenon light source is used. The MHA telescope was compact and unobtrusive, and enabled the surgeon to operate alone, without the otherwise mandatory surgical assistant. While the procedure can be performed with an assistant, the use of the MHA telescope offers several advantages, including image stability, lack of operator fatigue, reduced crowding of surgical field and reduced personal costs. Appropriate positioning was imperative for effective triangulation of the instruments. Optimal MHA telescope positioning was achieved when the telescope was angled
Veterinary Record | October 25, 2014
perpendicular to the table in the mid-dorsal region of the prefemoral incision. Based on our observations, improper positioning resulted in poor instrument triangulation, prolonged operating times and surgeon frustration. Improved instrument dexterity and reduced surgical times were appreciated as surgeon experience increased. In the authors’ opinion, previous endosurgical training is necessary when attempting to perform any endosurgical procedure, including coelioscopic orchiectomy. Results for the seven tortoises described in the present report suggest that coelioscopic orchiectomy is a feasible and practical method for performing orchiectomy in desert tortoises. Chelonian spermatozoa are known to persist within the epididymis for four to six months (Lofts and Tsui 1977), and therefore it may be wise to keep orchiectomised males away from fertile females for 12 months (Innis and others 2013).
Acknowledgements
The authors thank Lynn Reece, Emily Garber and Rob Miller for technical assistance. Funding Supreme Pet Foods provided financial support for Dr Proenca’s residency and also helped fund this research study. Major funding for the study was provided by Clark County, Nevada Desert Conservation Program. Karl Storz Veterinary Endoscopy Inc provided equipment support for research and development.
References
DIVERS, S. J., STAHL, S. J. & CAMUS, A. (2010) Evaluation of diagnostic coelioscopy including liver and kidney biopsy in freshwater turtles (Trachemys scripta). Journal of Zoo and Wildlife Medicine 41, 677–687 HARMS, C. A., PAPICH, M. G., STAMPER, M. A., ROSS, P. M., RODRIGUEZ, M. X. & HOHN, A. A. (2004) Pharmacokinetics of oxytetracycline in loggerhead sea turtles (Caretta caretta) after single intravenous and intramuscular injections. Journal of Zoo and Wildlife Medicine 35, 477–488 HELMICK, K. E., PAPICH, M. G., VLIET, K. A., BENNETT, R. A. & JACOBSON, E. R. (2004) Pharmacokinetic disposition of a long-acting oxytetracycline formulation after single-dose intravenous and intramuscular administrations in the American alligator (Alligator mississippiensis). Journal of Zoo and Wildlife Medicine 35, 341–346 INNIS, C. J., FEINSOD, R., HANLON, J., STAHL, S., OGUNI, J., BOONE, S., SCHNELLBACHER, R., CAVIN, J. & DIVERS, S. J. (2013) Coelioscopic orchiectomy can be effectively and safely accomplished in chelonians. The Veterinary Record 172, 526–526 KINNEY, M. E., JOHNSON, S. M. & SLADKY, K. K. (2011) Behavioral evaluation of red-eared slider turtles (Trachemys scripta elegans) administered either morphine or butorphanol following unilateral gonadectomy. Journal of Herpetological Medicine and Surgery 21, 54–62 LAWSON, G. O. & GARSTKA, W. R. (1985) Castration of turtles, Pseudemys scripta. Journal of Alabama Academic Science 56, 89 LICHT, P., KHORRAMI-YAGHOOBI, P. & PORTER, D. A. (1985) Effects of gonadectomy and steroid treatment on plasma gonadotropins and the response of superfused pituitaries to gonadotropin-releasing hormone in the turtle Sternotherus odoratus. General and Comparative Endocrinology 60, 441–449 LOFTS, B. & TSUI, H. W. (1977) Histological and histochemical changes in the gonads and epididymides of the male Soft shelled turtle, Trionyx sinensis. Journal of Zoology 181, 57–68 MASSARWEH, N. N., COSGRIFF, N. & SLAKEY, D. P. (2006) Electrosurgery: history, principles, and current and future uses. Journal of the American College of Surgeons 202, 520–530 O’MALLEY, B. (2005) Tortoises and turtles. In Clinical Anatomy and Physiology of Exotic Species. Editor: O’MALLEY. London: Elsevier Saunders. pp 41–56 RIVERA, S., DIVERS, S. J., KNAFO, S. E., MARTINEZ, P., CAYOT, L. J., TAPIAAGUILERA, W. & FLANAGAN, J. (2011) Sterilisation of hybrid Galapagos tortoises (Geochelone nigra) for island restoration. Part 2: phallectomy of males under intrathecal anaesthesia with lidocaine. The Veterinary Record 168, 78–78
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Single surgeon coelioscopic orchiectomy of desert tortoises ( Gopherus agassizii) for population management L. M. Proença, S. Fowler, S. Kleine, J. Quandt, C. O. Mullen and S. J. Divers Veterinary Record 2014 175: 404 originally published online July 11, 2014
doi: 10.1136/vr.102421 Updated information and services can be found at: http://veterinaryrecord.bmj.com/content/175/16/404
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Paper Single surgeon coelioscopic orchiectomy of desert tortoises (Gopherus agassizii) for population management L. M. Proença, S. Fowler, S. Kleine, J. Quandt, C. O. Mullen, S. J. Divers Orchiectomy in chelonians is a challenging procedure, especially in large species with deep and elongated testes and extensive mesorchial attachments. Single surgeon coelioscopic orchiectomy was performed in seven adult desert tortoises (Gopherus agassizii), maintained at the Desert Tortoise Conservation Center (DTCC) in Las Vegas, for population management. Surgery was successfully conducted through a bilateral prefemoral approach via sequential vascular clip ligation and radiosurgery (monopolar/bipolar). Bipolar endoscopic forceps were considered indispensable due to the extensive mesorchial attachments and their close association with the kidney. A mechanical arm was effectively used to permit orchiectomy to be completed by a single surgeon. Six of seven animals recovered from anaesthesia. Necropsy demonstrated that the death of the other was unrelated to surgical complications. One animal experienced surgically significant haemorrhage, but still made a clinical recovery. The six tortoises were returned to the DTCC and, six months postoperatively, remain healthy. This small study suggests this minimally invasive technique is an effective method for bilateral orchiectomy in desert tortoises and might be preferable in large chelonians with elongated testes.
Introduction
The desert tortoise (Gopherus agassizii) occurs over large portions of the Mojave and Sonoran Deserts in the southwestern USA and northwestern Mexico. It was designated as threatened under the US Endangered Species Act 1973. Abandoned and relinquished ‘pet’ tortoises, uncontrolled backyard breeding of ‘pets’ and displacement from urban development have resulted in thousands of animals received by the Desert Tortoise Conservation Center (DTCC) in Las Vegas, Nevada. While most of Nevada desert tortoises are experimentally relocated to appropriate and controlled habitat within the state, an urgent solution to this critical problem is required. This paper reports a study to evaluate endosurgical sterilisation in this species with the goal of decreasing backyard reproduction. Orchiectomy in chelonians is a challenging procedure since the testes are located in the dorsocaudal coelomic cavity, intimately associated with the kidney, below the carapace. The mesorchium of chelonians is short and tight, such that the testes cannot be exteriorised from Veterinary Record (2014) L. M. Proença, DVM, MSc, PhD, S. Kleine, DVM, J. Quandt, DVM, MS, DACVAA, DACVECC, S. J. Divers, BVetMed, DZooMed, DACZM, DECZM, FRCVS, Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Drive, Athens, GA 30602, USA S. Fowler, DVM,
doi: 10.1136/vr.102421 C. O. Mullen, PhD, U.S. Fish and Wildlife Service, Desert Tortoise Recovery Office, 777 E. Tahquitz Canyon Way, Suite 208, Palm Springs, CA 92262, USA E-mail for correspondence: [email protected], cc: [email protected] Provenance: not commissioned; externally peer reviewed Accepted June 20, 2014
the coelom (O’Malley 2005, Innis and others 2013). Other sterilisation techniques such as phallectomy, orchiectomy via plastron osteotomy or prefemoral orchiectomies without coelioscopy have been performed in male chelonians, but all have disadvantages (Lawson and Garstka 1985, Licht and others 1985, Rivera and others 2011, Innis and others 2013). In contrast, prefemoral orchiectomy with the aid of coelioscopy offers a minimally invasive approach and has been shown to be effective, safe and appears to be a preferable method for sterilisation of male freshwater turtles because of improved surgical visualisation and accessibility, combined with shorter healing and recovery times (Innis and others 2013). The previously reported coelioscopic orchiectomy technique was accomplished by a single vascular clip or monopolar radiosurgery across a short mesorchium (Innis and others 2013). Different species have variable testicular anatomy, as well as seasonal and age-related testicular variations (Innis and others 2013). Consequently, the removal of larger testes in larger species would be more problematic, requiring additional internal dissection. For example, an attempt at coelioscopic orchiectomy of a hybrid Galapagos t ortoise (Geochelone nigra) was reported to have failed (Rivera and others 2011). The purpose of this study was to develop a feasible and effective method of endoscopic orchiectomy to be used in larger species, using the desert tortoise as a model. We describe an endosurgical technique that utilises a mechanical arm to permit orchiectomy to be completed by a single surgeon in chelonians with elongated testes.
Material and methods Animals
A group of seven adult male desert tortoises (G. agassizii) maintained at the US Fish and Wildlife Service and the DTCC in Las Vegas were used in a prospective study approved by the Animal Care and Use Committee (IACUC Number A2010 11-549-Y3-A1). October 25, 2014 | Veterinary Record
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Paper The tortoises were transported to the University of Georgia (UGA) and temporarily maintained in conditions approved by the Association for Assessment and Accreditation of Laboratory Animal Care. Each tortoise was physically examined and weighed on the day of arrival. Unique numbers were used to identify each individual. Upon arrival, blood was collected from a jugular vein with blood submitted in lithium heparin for packed cell volume (PCV) and total solids (TS).
Anaesthesia
The tortoises were simultaneously participating in a parallel anaesthesia study with specific anaesthesia data to be published separately. The animals were fasted for 48–72 hours prior to anaesthesia, although access to water was maintained. They were bathed in shallow, lukewarm water for two hours prior to the procedure to stimulate urination. Manual stimulation of the cloaca was also performed to promote bladder emptying before anaesthetic induction. Oxytetracycline (Liquamycin LA200, Pfizer) (5 mg/kg intramuscular) and meloxicam (Metacam, Boehringer Ingelheim) (0.2 mg/kg subcutaneous) were administered preoperatively (12–24 hours prior to surgery). The animals were physically restrained and induction was achieved using a combination of ketamine (Ketaset, Fort Dodge) (10 mg/kg) and dexmedetomidine (Dexdomitor, Pfizer) (50 µg/kg) administered intravenously into a jugular vein. Following induction, each animal was placed in a vertical (head up) position with pressure on the site of injection to reduce haematoma formation. The tortoises were randomly assigned to receive either a combination of lidocaine (2 mg/kg, lidocaine HCl 4 per cent, Hospira) and morphine (0.1 mg/kg, morphine sulfate, Hospira) or an equivalent volume of saline control intrathecally after induction. Jugular vein catheterisation was attempted in all animals using a 24 G intravenous catheter. If successful, 3 ml/kg/hour of lactated ringers solution (LRS) was administered intravenously. If unsuccessful, one dose of 25 ml/kg of LRS was administered subcutaneously. Each animal was intubated using an appropriately sized uncuffed endotracheal tube secured using a plastic mouth gag (FMG100, Plastic mouth gag, PetAg) and taped in position. The animals were maintained on 100 per cent oxygen for the duration of the procedure. Each tortoise was ventilated using a positive-pressure ventilator (Small animal ventilator VT-5000, BAS Vetronics, Bioanalytical Systems) at two breaths per minute and at a peak inspiratory pressure of 4–10 cm H2O. If additional anaesthesia was required, isoflurane was administered in oxygen and adjusted to patient requirements. Pulse was monitored with a Doppler ultrasonic flow detector (model 811-B; Parks Medical Electronics) placed over the carotid
Kidney
artery. A multiparametric monitor (LW6000 Multiparametric monitor, Digicare Biomedical Technology) was used to monitor end-tidal capnography (ETCO2), oesophageal temperature and ECG.
Endoscopic equipment and sterilisation
A 2.7 mm (wide view), 30°, 18 cm telescope (64019BA, Karl Storz, Tuttlingen, BW, Germany), endoscopic camera (22220055-3, Karl Storz), xenon light source (20132101-1, Karl Storz), imaging capture system (22201011U110, Karl Storz), mechanical holding arm (MHA) for the telescope (28272RKBKS, Karl Storz) and 3 mm endoscopic instrumentation were used (Karl Storz). Two monitors were connected to the camera to permit coelioscopy from either side of the table, and avoid moving the endoscopy tower if a bilateral coelioscopic procedure was required.
Prefemoral coeliotomy
Each tortoise was placed onto a heated surgery table (GMRTP22E, Heated water mattress, Gaymar Industries) maintained at 28–30°C. Each animal was positioned in right lateral recumbency using a vacuum bean bag positioner (SN103526, Natus, Planegg, Germany). Additional elevation of the head above the horizontal was undertaken to reduce the cranial movement of intrathecal medication. The hindlimbs were extended caudad and taped together to allow exposure of both prefemoral fossae. The left prefemoral fossa and surrounding shell were aseptically prepared and draped using standard techniques. A 5–6 cm craniocaudal skin incision was made in the cranial prefemoral fossa using a #15 scalpel blade. The subcutaneous tissues were bluntly dissected and the aponeurosis of the tendinosis parts of the ventral and oblique abdominal muscles identified and incised exposing the coelomic membrane. A 3 mm incision was made in the coelomic membrane to permit insertion of the telescope and confirmation of correct coeliotomy approach. The coelomic membrane incision was carefully extended, taking care not to damage the often voluminous and closely associated bladder, the septum horizontale (postpulmonary septum) or lung. A ring and elastic stay retractor (Lone star retractor, Cooper Surgical) was positioned to provide improved exposure of the coelom. The use of a single prefemoral coeliotomy incision permitted the use of multiple instruments without the need for additional cannulae.
Endoscopic orchiectomy
Following prefemoral coeliotomy, endoscopic examination of the coelomic cavity and identification of the left testis (Figs 1 and 3a), the
Testis
Lung
Large intestine
Colon Cloaca
Liver
Gall bladder Bladder
Small intestine
c 2013 UGA
FIG 1: Regional anatomy and instrument position during prefemoral coelioscopic orchiectomy of a male desert tortoise (Gopherus agassizii) in right lateral recumbency. Courtesy of Kip Carter, University of Georgia
Veterinary Record | October 25, 2014
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Paper
FIG 2: Mechanical holding arm (MHA) telescope orientation during prefemoral coelioscopic orchiectomy of a male desert tortoise (Gopherus agassizii). The optimal position of the MHA telescope was achieved when the telescope was positioned perpendicular to the table in the mid-dorsal region of the incision. A ring and elastic stay retractor was used to provide improved exposure of the coelom. Courtesy of Kip Carter, University of Georgia
MHA was used to secure the telescope in place. The MHA telescope was positioned to allow triangulation of the endosurgery equipment and optimal visualisation of the endosurgical field. Following correct positioning of the MHA telescope (Fig 2), the testis was grasped at the caudal aspect using 3 mm atraumatic endoscopic forceps with ratchet handle (303530N, Karl Storz), inserted alongside the telescope. The left (non-dominant) hand of the surgeon was used to secure and elevate the testis to expose the mesorchium and associated blood vessels (Fig 3b). The surgeon’s right (dominant) hand was used to manipulate 3 mm short curved Metzenbaum endoscopic scissors (30310MSS, Karl Storz) (Fig 3d), connected to a monopolar radiosurgery unit (Surgitron 4.0 MHz, Ellman International), 3 mm bipolar endoscopic forceps (26184HCS, Karl Storz) (Fig 3c), or medium to large stainless steel vascular clips (LT400 Vascular clips, Ethicon Endosurgery; 523600 Hemoclips, Teleflex) (Fig 3e) with curved or straight applicators. A combination of these instruments was used to dissect the testis free from its mesorchial attachments, paying careful attention to haemostasis. As the mesorchial transection proceeded in a caudal to cranial direction, the grip on the testis was adjusted to permit better exposure of the remaining mesorchium. After complete removal of the left testis, the coelomic cavity was inspected to verify haemostasis (Fig 3f). Visualisation of the contralateral (right) testis, through the left prefemoral approach, was attempted. If not possible, a bilateral procedure was elected. The left prefemoral coeliotomy was closed in a routine manner. Absorbable suture, poliglecaprone 25 (Monocryl-Plus; Ethicon) 3–0, on a tapered needle in a simple continuous pattern was used to close the coelomic aponeurosis and associated subcutaneous tissues in a single layer. The skin was closed using 3–0 poliglecaprone 25 on a cutting needle using a simple horizontal mattress pattern. If the right testis was not removed, the procedure was repeated via the right prefemoral fossa to remove the second testis. An adapted published scoring scale (Divers and others 2010) was used on this study. The ease of gonad visualisation was scored from 0 to 3 (0, no manipulation required; 1, minor manipulation; 2, major manipulation; and 3, impossible) for right and left testes. Ease of visualisation of the right gonad through a left prefemoral approach was scored from 0 to 3 (0, no manipulation required; 1, minor manipulation; 2, major manipulation; and 3, impossible). Ease of resection of both testes (right and left) was scored from 0 to 3 (0, simple; 1, minor
difficulty; 2 major difficulty; 3, impossible). Coeliotomy time (from start of the prefemoral incision to time of telescope entry) for the left and right side was individually recorded. Total surgery time (from start of the left prefemoral incision to the end of last suture on the right prefemoral fossa), left approach surgery time (from start of the left prefemoral incision to the end of last suture on the left prefemoral fossa) and right approach surgery time (from start of the right prefemoral incision to the end of last suture on the right prefemoral fossa) were accessed and recorded. All surgeries were performed by either one of two authors (Proença and Divers).
Postoperative care
All tortoises received postoperative hydromorphone (West-Ward) (0.5 mg/kg intramuscular) for pain management. If present, the intravenous catheter was removed once recovered and ambulatory. The animals were kept in recovery holding pens, without substrate, food or water, for the first 12–24 hours, until fully recovered. Each animal was given additional doses of oxytetracycline (5 mg/kg, intramuscular) and meloxicam (0.2 mg/kg, subcutaneous) daily for three days. Incisions were inspected daily for the duration of their hospitalisation at UGA (6–16 days postsurgery). Postoperative weights, PCV and TS were performed before discharge.
Results
Mean preoperative weight of the seven animals was 7.02 kg (range 5.94–8.36 kg). Results of preoperative physical examination revealed no abnormalities, except for animal number seven, which presented a scar on the left prefemoral fossa that may have been associated with a previous surgery. Preoperative results for PCV and TS were within the normal limits, with a mean of 26 per cent (range 24–29 per cent) and 35 g/l (range 29–40 g/l), respectively. No tortoises voided urine despite manual attempts to empty the bladder, but a few animals may have urinated during the bath in lukewarm water as faecal material was observed in the water. Despite unremarkable preoperative physical examinations, significant abnormalities were observed during coelioscopy of animals two, three and seven. Animal number two exhibited pale serosa of coelomic organs and what appeared to be vasoconstricted blood vessels, with an almost imperceptive pulse in coelomic arteries. Animal number three exhibited evidence of severe liver disease, and animal October 25, 2014 | Veterinary Record
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Paper
FIG 3: Coelioscopic orchiectomy of a male desert tortoise (Gopherus agassizii) via sequential vascular clip ligation and radiosurgical dissection. (a) Telescope view of the caudal coelom via a left prefemoral approach. (b) Atraumatic endoscopic forceps (F) used to expose the mesorchium and associated vasculature (arrow). (c) Stainless steel vascular clip (arrow) has been placed on the caudal aspect of the mesorchium, close to the kidney, prior to mesorchial coagulation using bipolar forceps (B). (d) Mesorchial dissection using short curved Metzenbaum scissors (S). (e) Placement of vascular clip (arrow) across the cranial aspect of the mesorchium. (f) View of the ligation clips (arrows) across the mesorchium remnant following excision of the testis. L, Lung; K, kidney; T, testis; C, colon; M, mesorchium
number seven had a large abscess in the left caudal lobe of the liver causing adhesion of the liver to the body wall. The surgical scores and times are summarised in Table 1. The ease of gonad visualisation for both right and left testes was consistently excellent (score 0), when approached through their respective sides. Ease of visualisation of the right gonad through the initial left prefemoral approach was never possible (score 3), and a bilateral approach was invariably required for all seven animals. Ease of testicular resection varied from simple (0) to major difficulty (2), but was successfully completed in all cases. The epididymis was not removed. The mean score for surgical ease was 0.85 for the right testis and 0.42 for the left testis (ie, between simple (0) and minor difficulty (1)). Left and right coeliotomy times were five and four minutes on average, respectively. Total surgery time was 154 minutes on average, with a mean of 82 minutes for left side and 72 minutes for the right side. The dark brown and smooth testes, approximately 6–8 cm in length and 0.5–1.5 cm wide, were tubular with tapering ends, and extended from the deep pelvic region medially towards the bridge of the shell laterally. The mesorchium was short with the caudal two-thirds closely attached to the ventral surface of the kidney. The epididymis was easily identified attached to the mid to caudal extent Veterinary Record | October 25, 2014
of the testis, and closely associated with the ventral aspect of the kidney. Bilateral orchiectomy was achieved via sequential vascular clip ligation and radiosurgery (monopolar and bipolar) starting at the caudal pole of the testis, and progressing craniad. Vascular clips were applied when large blood vessels were encountered, especially at the caudal, middle and cranial aspects of the mesorchium. Vascular clips were applied as close to the kidney as possible, and the mesorchium transected distal to the clip as close as possible to the testis. Special care was taken not to leave any testicular tissue behind (Fig 3). The size of the clips and shape of the applicator (curved or straight) were chosen based on the size of the vessel and position of the testis in relation to the incision, respectively. Bipolar endoscopic forceps were used when large vessels were not present and the space between the testis and kidney was considered too small for the use of monopolar scissors that create greater collateral tissue damage (Fig 3c). Following the use of the bipolar forceps, the 3 mm Metzenbaum endoscopic scissors were used to transect the cauterised mesorchium. Where there was sufficient space between kidney and testis, the Metzenbaum endoscopic scissors were used as a monopolar device to both effect haemostasis and transection of
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Paper TABLE 1: Endoscopy scores and surgery times for coelioscopic orchiectomy in seven desert tortoises (Gopherus agassizii)
Animal number
Ease of gonad visualisation right testis (right approach)*
1 2 3 4 5 6 7 Mean sd
0 0 0 0 0 0 0 0 0
Ease of gonad visualisation left testis (left approach)* 0 0 0 0 0 0 0 0 0
Ease of gonad visualisation right testis (left approach)* 3 3 3 3 3 3 3 3 0
Ease of resection of the right testis†
Ease of resection of the left testis†
0 0 2 1 1 2 0 0.85 0.89
0 0 1 0 1 0 1 0.42 0.53
Total surgery time (minutes) 128 117 187 114 174 183 179 154 33
Right approach surgery time (minutes) 68 40 94 56 80 100 69 72 20
Left approach surgery time (minutes) 60 77 93 58 94 83 110 82 18
Right coeliotomy time (minutes)
Left coeliotomy time (minutes)
2 2 11 3 3 5 3 4.14 3.18
3 6 1 19 3 2 3 5.28 6.23
*From 0 to 3 (0, no manipulation required; 1, minor manipulation; 2, major manipulation; and 3, impossible) †From 0 to 3 (0, simple; 1, minor difficulty; 2, major difficulty; 3, impossible)
the mesorchium (Fig 3d). Greater care was required to allow current to be applied only to the mesorchium without touching the kidney or other surrounding tissues. The radiosurgery unit was set to cut/ coagulation with power settings varied from 10 to 45 digital units or approximately 15–45 W. Particular care was taken to retract the testis away from the adjacent colon, lung, urinary bladder, kidneys and adrenal gland during dissection of the mesorchium. Correct positioning of the MHA telescope was essential to provide the best view and promote triangulation of the instruments. The optimal MHA telescope orientation was achieved when the telescope was positioned perpendicular to the table, in the mid-dorsal region of the incision (Fig 2). As the mesorchial transection proceeded in a caudal to cranial direction, the position of the MHA telescope was adjusted to permit closer view of the surgical site. All animals recovered from anaesthesia, with the exception of number two. Necropsy of this tortoise revealed hepatic lipidosis (diffuse, moderate to severe) and a large 5 cm×2 cm haematoma associated with the jugular vein (consistent with vein cannulation). No evidence of surgical complications was observed and the death was considered related to anaesthesia and pre-existing disease. Profuse haemorrhage occurred during resection of the right testis of number six. The haemorrhage occurred during final resection of the cranial aspect of the mesorchium, closely associated with the kidney, after the last vascular clip placement. Attempts were made to promote haemostasis using pressure (with sterile cotton tip applicators) and radiosurgery, and a partial reduction in bleeding was achieved. The animal’s coelom was copiously flushed with warm sterile saline before closure, with the animal monitored closely during the following 24 hours. Postoperative PCV and TS were decreased from 26 to 18 per cent and from 38 to 25 g/l, respectively. All remaining animals were observed eating the day following surgery. Mean postoperative PCV and TS were 25 per cent (range 18–30 per cent) and 27 g/l (range 25–32 g/l), respectively. There was no significant weight loss, postoperatively (mean weight 6.9 kg, range 6.12–8.74 kg). The six tortoises were returned to the DTCC and, six months postoperatively, remain healthy.
Discussion
Surgical sterilisation of male chelonians is not commonly performed. An effective technique of neutering red-eared terrapins (Trachemys scripta elegans) without the use of coelioscopy has been previously described (Kinney and others 2011). However, this method relies on the ability of the surgeon to visualise and manipulate the gonad through a small incision, using the unaided eye. The magnification and optimal visualisation provided by coelioscopy seems to be preferable in small species, such as red-eared terrapins, and essential in larger chelonians, such as Amazon River turtle (Podocnemis unifilis), but objective comparison requires future controlled studies (Innis and others 2013). In the authors’ opinion, orchiectomy without coelioscopy in larger species, such as the desert tortoise with longer and deeper testes, is not possible. Exteriorisation of the testicle is not feasible due to the short mesorchium attachment; therefore,
complete visualisation of the entire testicle is not achievable with the unaided eye, especially the cranial aspect, where the testicle is closely associated with the kidney and a large blood vessel is present and need to be properly ligated/coagulated. Endoscopic orchiectomy techniques have been described for three different species of chelonians: red-eared terrapin, Amazon River turtle and painted turtle (Chrysems picta picta). For smaller species, redeared terrapin and painted turtle (mean weight of 436 g), orchiectomy was conducted with a unilateral technique using a single vascular clip and/or radiosurgical transection of the mesorchium, requiring no major dissection. It is important to appreciate that, similar to the orchiectomy without coelioscopy, this method was only possible because of the small size and spherical shape of the testis (Innis and others 2013). By contrast, the procedure in the Amazon River turtle was protracted and more difficult, requiring a bilateral approach due to the different anatomy of the gonads (Innis and others 2013). The mean score for surgical excision of both testes was similar, between simple to minor difficulty. The slightly higher mean score for the right side was partially due to complications associated with tortoise number six. Visualisation on the contralateral testis through the left prefemoral approach was not possible in any animal. It is unclear if the ability of the surgeon, location of testes or a combination of factors could be responsible. Nevertheless, even if visualisation of the contralateral testis were possible, resection of both gonads via a unilateral approach would be more difficult. Mean surgery times for left and right orchiectomies were similar, 82 and 72 minutes, respectively. Mean total surgery time was 154 minutes, which was longer than that reported using similar techniques in other species, probably attributable to the longer testes of the desert tortoise (Innis and others 2013). These differences are probably compared with the red-eared terrapin (0.5–1 cm) and Amazon River turtle (4–5 cm) (Innis and others 2013). In this study, bilateral orchiectomy was achieved via sequential vascular clip ligation and radiosurgery (monopolar/bipolar). Although bipolar endoscopic forceps were not described in previous publications, they were considered indispensable for desert tortoise orchiectomy. Bipolar instruments resemble surgical forceps, with both the active electrode and the return electrode functions being performed at the surgical site, and confined only to the tissue between the forceps. Consequently, bipolar energy delivery reduces the chances of collateral damage to closely associated tissues, even if one electrode is touching an adjacent tissue. Contrarily, monopolar instruments offer a greater risk of collateral tissue damage, since the energy delivered by the instrument needs to travel through the animal and back to the generator through a conductive grounding pad placed under the patient (Massarweh and others 2006), and therefore any tissue inadvertently touched would be affected. In the desert tortoise, the mesorchial attachments are extensive and closely associated with the kidney. In these areas, bipolar radio surgery offers considerable advantages by avoiding collateral damage to the kidney and closely associated vasculature. The use of monopolar scissors is certainly possible and encouraged where the mesorchium width is larger, and enough space October 25, 2014 | Veterinary Record
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Paper exists between the instrument and adjacent kidney. The authors do not advise performing orchiectomy in mid to large chelonians without having bipolar endoscopic forceps available. In addition, a variety of vascular clip sizes and applicators are also useful and recommended. Contrary to previous reports, no complications (eg, perforation of the urinary bladder and inadvertent entry into the retrocoelomic space) were observed during coeliotomy (Innis and others 2013). The larger size of desert tortoises may have helped reduce these surgical complications. Although attempted, cloacal stimulation to encourage urination was not successful, and full urinary bladders were often observed upon entry. If concerns regarding large bladders exist, then ultrasound-guided cystocentesis or percloaca urethral catheterisation via cloacoscopic guidance could be considered. Number six was the only animal that endured surgical complications. Profuse haemorrhage occurred during final dissection of caudal aspect of the right mesorchium. Analysis of the endosurgery video suggested that telescope positioning was less than ideal and too far away from the surgical site. Therefore, a blood vessel, closely associated with the kidney, was not fully appreciated during vascular clip placement and only partial ligation was achieved. Despite significant blood loss, anaesthesia recovery was unremarkable and the animal demonstrated no clinical disadvantage. Number two did not recover from anaesthesia and necropsy demonstrated that death was unrelated to surgery or haemorrhage. However, a large haematoma, associated with the jugular vein, was found at necropsy, and demonstrates that a head-up position and local pressure may not prevent bleeding following venipuncture. Despite unremarkable preoperative physical examinations, significant abnormalities were observed during coelioscopy in three of the seven animals, which could complicate anaesthetic and surgical outcomes and should always be taken into consideration before submitting the patient through a surgical procedure. Due to the small number of tortoises used in the present research, further studies involving a larger number of animals are needed to assess the safety of coelioscopic orchiectomy in medium to large size tortoises. The use of antibiotics for routine sterilisation is controversial because of the possibility of causing antibacterial drug resistance. In this study, we started oxytetracycline preoperatively and repeated dosing for three days postoperatively at a dose of 5 mg/kg. To the authors’ knowledge, there is no pharmacokinetically derived oxytetracyline dose available for tortoises; however, pharmacokinetically derived doses of 10 mg/kg every five days in American alligators (Alligator mississippiensis) or of 25 mg/kg every 61 hours in sea turtles (Caretta caretta) may have been more appropriate (Harms and others 2004, Helmick and others 2004). Since the testes in chelonians are located in the dorsocaudal coelomic cavity, below the carapace, it is imperative that the telescope is equipped with a 30° angle to allow visualisation of the gonad. In the authors’ experience, the length of the telescope is not significant since inserting the instrument more than only few centimetres in the coelom caused instrument stumping (Fig 2). The 2.7 mm telescope is likely to be suitable for the procedure in larger chelonians, as long as a xenon light source is used. The MHA telescope was compact and unobtrusive, and enabled the surgeon to operate alone, without the otherwise mandatory surgical assistant. While the procedure can be performed with an assistant, the use of the MHA telescope offers several advantages, including image stability, lack of operator fatigue, reduced crowding of surgical field and reduced personal costs. Appropriate positioning was imperative for effective triangulation of the instruments. Optimal MHA telescope positioning was achieved when the telescope was angled
Veterinary Record | October 25, 2014
perpendicular to the table in the mid-dorsal region of the prefemoral incision. Based on our observations, improper positioning resulted in poor instrument triangulation, prolonged operating times and surgeon frustration. Improved instrument dexterity and reduced surgical times were appreciated as surgeon experience increased. In the authors’ opinion, previous endosurgical training is necessary when attempting to perform any endosurgical procedure, including coelioscopic orchiectomy. Results for the seven tortoises described in the present report suggest that coelioscopic orchiectomy is a feasible and practical method for performing orchiectomy in desert tortoises. Chelonian spermatozoa are known to persist within the epididymis for four to six months (Lofts and Tsui 1977), and therefore it may be wise to keep orchiectomised males away from fertile females for 12 months (Innis and others 2013).
Acknowledgements
The authors thank Lynn Reece, Emily Garber and Rob Miller for technical assistance. Funding Supreme Pet Foods provided financial support for Dr Proenca’s residency and also helped fund this research study. Major funding for the study was provided by Clark County, Nevada Desert Conservation Program. Karl Storz Veterinary Endoscopy Inc provided equipment support for research and development.
References
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Single surgeon coelioscopic orchiectomy of desert tortoises ( Gopherus agassizii) for population management L. M. Proença, S. Fowler, S. Kleine, J. Quandt, C. O. Mullen and S. J. Divers Veterinary Record 2014 175: 404 originally published online July 11, 2014
doi: 10.1136/vr.102421 Updated information and services can be found at: http://veterinaryrecord.bmj.com/content/175/16/404
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