Laparoscopy and Coelioscopy

Laparoscopy encompasses MIS procedures in the abdominal cavity. Coelioscopy, which is endoscopy of the coelomic cavity in nonmammalian species, is also commonly referred to as laparoscopy, although this usage is not strictly accurate. This is the most widely recognized and the best reported MIS technique in the zoo and wildlife surgical field. It has been applied in mammal species ranging from mice⁵⁶ to elephants,⁵⁸ as well as in birds, reptiles, amphibians, and fish.^10,39 It has applications in diagnosis, surgery, and assisted reproduction in wildlife. The emphasis in this chapter is on laparoscopy and coelioscopy, as still relatively few reports on the application of other MIS modalities in wildlife have been published.

Thoracoscopy

Thoracoscopy holds potential for further application in zoo animal surgery. Maintenance of postoperative chest drains commonly employed in open thoracotomy procedures is difficult in wildlife patients. Many human surgeons prefer the term video-assisted thoracic surgery (VATS) to thoracoscopy, which highlights one of the main benefits that endosurgery brings to thoracic surgery—visualization. Endoscopic visualization allows examination of parts of the pleural cavity, which are difficult to access or see adequately in open thoracotomy procedures. VATS also recognizes that although the majority of a procedure such as a lung lobectomy can be completed thoracoscopically, a mini-thoracotomy is usually still needed for tissue extraction. In laparoscopy, alternatives such as insertion of hand access ports, motorized tissue morcellators, and rip-proof impervious extraction bags allow an entire liver lobe to be broken down with sponge forceps and extracted through a 10- to 15-millimeter (mm) port site.

Currently, published thoracoscopy reports have largely been limited to those on laboratory primates such as macaques⁴ and domestic animals.⁴⁰ Postmortem thoracoscopic access was assessed in an adult giraffe, but visualization and access were notably limited by the wide, closely spaced ribs that allowed for little angulation of the endoscope and instruments,⁴⁴ which is also an issue with other large herbivores and megavertebrates. Access was, however, sufficient for peripheral lung biopsies. Thoracoscopy is not possible in elephants because of the lack of a pleural space.⁸

Vascular ring anomalies such as persistent right aortic arch have been treated in zoo animals such as a tiger by open thoracotomy,²² and the procedure has been performed in domestic animals via 3-mm thoracoscopy,⁴⁰ making this equally applicable in zoo animals not intended for breeding. Esophageal hiatal hernias, diaphragmatic hernias, and chylothorax, reported in zoo species,^19,21,23,29 are amenable to operative thoracoscopy techniques.

The extracorporeal applied Meltzer knot (Figure 72-1), which is an extremely useful technique for performing lung biopsies, also has other MIS and open surgery applications. It can be used in a wide range of taxa and body sizes, in cases where alternatives such as endosurgical staplers cannot be used. It is more cost effective than staplers or commercially available pretied endoloops (Surgitie, Covidien; Endoloop, Ethicon). This also allows surgeons greater choice of suture material and diameter than commercially available endoloops. The author has used this in species ranging from 1 to 650 kilograms (kg), via 3-mm ports and larger ports in thoracoscopy and laparoscopy. A loop with a pretied Meltzer knot is inserted via one port with a knot pusher and grasping forceps inserted via a different port. The forceps end is passed through the loop to grasp the tissue to be ligated for purposes such as biopsy. The tip of the knot pusher is then placed on the tissue where ligation is required, and the suture loop tightened, thus locking the knot. Knot ends of about 1 centimeter (cm) length should be left for safety. The tissue may then be transected. A suture may also be first passed around a fixed structure such as the cystic duct or ligamentum arteriosis before the suture exits from the same port, and the knot is then tied and similarly placed with a knot pusher for ligation.

Surprisingly few reports of arthroscopic surgery in wildlife species have been published, considering how widespread and established the use of this MIS modality is in domestic animals. Two reports of arthroscopy in giraffe—one of arthroscopic treatment of a metacarpophalangeal joint injury and osteochondral fragment,⁵⁰ and the second of exploratory arthroscopy in the femorotibial joint of a giraffe with an avulsion fracture of the peroneus tertius origin—have been published.⁴⁹ Arthroscopy has also been reported in the Dromedary camel,^2,36 alpaca, and llama.³⁷With the increased longevity of zoo animals and the associated needs for diagnosis and management of geriatric conditions such as osteoarthritis, arthroscopy is likely to be increasingly performed in individual zoo animals in future. Arthroscopy also has a potential role to play in the diagnosis of some dysplastic joint diseases that may have heritable factors, with subsequent implications for captive breeding.

Further studies are needed to clarify optimal safe entry sites in the joints of different species, particularly in species that markedly differ anatomically from domestic animal models and humans. Poor site selection for joint entry or lack of experience in the operators poses the risk of cartilage and joint damage. In larger animals, as in domestic equines, insufflation of the joints with carbon dioxide may be helpful in improving visualization.⁵¹

Percutaneous Surgical Interventions

Interventional procedures include interventional radiology, interventional cardiology, and ultrasound-guided procedures. Some conditions that were surgically managed previously are increasingly performed via percutaneous techniques, which hold potential applications in wildlife species. These include occlusion of patent ductus arteriosis, balloon valvuloplasty for pulmonic stenosis, cardiac pacemaker implantation, and attenuation of single portosystemic shunts, performed under fluoroscopy. These percutaneous techniques are all based on the Sildinger technique of vascular access.⁵⁵ The implantation of a cardiac resynchronization device in a gorilla has been reported,^52,53 and in the future more interventional procedures may be used for managing the health and welfare of nonbreeding great apes, carnivores, and other charismatic exhibit animals.

Ultrasound-guided procedures are also replacing surgical procedures used previously and even other more invasive MIS techniques such as laparoscopy in some applications. Much of the initial research on wildlife laparoscopy was focused on its applications in assisted reproduction, such as examination of ovaries, artificial insemination, and oocyte retrieval.^5,8 These applications of laparoscopy are increasingly being replaced by ultrasonography, transcervical insemination, and transvaginal ultrasound-guided fine-needle techniques. Trans­rectal ultrasound-guided oocyte recovery has been performed in white and black rhinoceroses,¹⁸ in which, as in other megavertebrates, laparoscopic access to the ovaries is not easily achieved.^44,58

Other Endosurgical Techniques

Other rigid and flexible endoscopic modalities may be used for both diagnostic and operative applications, although only a small number of reports of their operative use in wildlife have been published. Operative rhinoscopy has been used to remove obstructing nasal polyps in a chimpanzee¹² and a California sea lion.⁵⁷ Endoscopy, in conjunction with fluoroscopy, may be used to apply temporary or permanent stents. Urethral stenting, in conjunction with laser lithotripsy, has been used in a bottlenose dolphin⁵⁴ and an Asian small-clawed otter.⁶⁶ Bilateral urethral stenting in a Guinea baboon has been reported in the management of urethral strictures caused by endometriosis that occurred after an ovariohysterectomy.⁹ The author is unaware of any reports of permanent stenting for tracheal collapse in zoo animals, but the technique appears feasible in many mammalian species, should it be needed.

Natural orifice transluminal endoscopic surgery (NOTES) has been investigated for its potential for truly “scarless” surgery in human abdominal surgery. Transvaginal and transgastric cholecystectomies have been performed in humans, as an alternative to laparoscopy or open surgery. However, the use of NOTES in human surgery is still highly controversial and has only been performed in a small number of cases. Besides studies in laboratory animals, NOTES has been investigated experimentally in domestic horses for standing bilateral ovariectomies with reasonable initial technical results.³⁴ Transvaginal laparoscopy for oocyte retrieval was investigated in a black rhinoceros,⁴⁸ as a potential alternative to flank laparoscopy, but the technique was problematic and has been replaced by other less invasive methods such as an ultrasound-guided fine-needle transrectal technique,¹⁸ which appears safer and more feasible.

Cosmesis is the main reason for the development of NOTES in human surgery and is of little concern in wildlife patients. The need for expensive specialist equipment such as double-channel operative flexible endoscopes; difficulties in monitoring surgical entry sites in the stomach, rectum, or vagina postoperatively; increased technical difficulty and increased procedure time; and ongoing controversy over its safety and benefits in humans make it unlikely that NOTES will find much application in wildlife surgery in the near future.

Cognitive Bias in Wildlife MIS

Cognitive bias caused by heuristics and subsequent errors in decision making need to be recognized in wildlife MIS.⁶¹ Veterinary surgeons able to perform MIS may inadvertently be subject to the risk of “technology bias,” or “law of the instrument,” which is summed up by Maslow as follows: “If the only tool you have is a hammer, everything looks like a nail.”²⁸ All surgery, even MIS, is invasive and carries risks of adverse consequences for the patient. A 2010 study in the British Journal of Surgery found that not only were a significant number of human elective surgery patients not better a year after elective surgery, 17% actually suffered worse pain than before surgery, and 14% had less function than before surgery.³⁸ This indicates that approximately 1 in 7 human elective surgery patients are, in fact, worse off a year later after the surgery. No comparable veterinary data are available, but it is uncertain whether veterinary surgical patients fare any better. It is strongly recommended that wildlife surgical decisions be routinely discussed with nonsurgical colleagues, to evaluate if a procedure is technically feasible and if it, in fact, is indicated, carries a reasonable likelihood of a successful outcome for the patient, and another equally applicable nonsurgical option is not available. Without this consideration, everything may start to resemble “a chance to cut being a chance to cure,” rather than “Primum non nocere” (“First do no harm”). Auditing surgical outcomes is vital to improving surgical skills and reducing complications, as well as to improving future surgical decisions.

MIS being less invasive does not always mean that it is better than open surgery. Recent systematic reviews have found no evidence for better long-term oncologic or functional outcomes among open prostatectomy, laparoscopic prostatectomy, and robotic radical prostatectomy in men.^14,24

Wildlife surgeons may benefit from surgical research into nonpatient factors that affect surgery on humans, domestic animals, and wildlife equally. Even relatively small changes in surgical practice may have a large influence on patient safety and outcomes. Under the World Health Organization (WHO) “Safe surgery saves lives” initiative, the use of a simple surgical checklist in human surgery has been found to reduce surgical complications by more than one third and reduce deaths by almost half.²⁷ A safety checklist modified for veterinary endosurgery can be downloaded from http://www.veterinarylaparoscopy.com/Vet endosurgery safety checklist.pdf.

Cognitive bias may also lead to the belief that new equipment or additional instrumentation would improve surgical capabilities and the procedures that can be performed, when the procedures may not, in fact, be necessary. The author is aware of several hundred laparoscopic cholecystectomies safely and rapidly performed by experienced surgeons in human medicine working in developing countries, when electrosurgery was not available, simply by careful and meticulous dissection.⁵⁹ When performing laparoscopic cholecystectomies in bears (Figure 72-2), self-tied extracorporeal knots may be the only viable option for ligation of the cystic duct, as clips are too small and access for 12-mm diameter endosurgical staplers is insufficient.⁴⁵

Emphasis is commonly placed on the small wounds and reduced postoperative pain in veterinary MIS. However, the enhanced magnified visualization, access to parts of the body and structures difficult to visualize in open surgery, provision of excellent illumination, and ability to perform less traumatic and more physiologic surgery in MIS are also of considerable value to the wildlife surgeon. Reducing the invasiveness of surgical procedures through different MIS techniques should not, however, be accomplished at the cost of increased risks to the patient.⁴⁶