Chapter 68 Laparoscopic Surgery in the Elephant and Rhinoceros
Traditional abdominal surgery in the elephant and rhinoceros has rarely been performed and, in those cases in which it has, success has been limited.1,4 Emergency cesarean sections in elephants have been attempted and have proved fatal for both the calf and mother. Successful castration of bull elephants has been described.2,3,12 In these reports, young animals were castrated in a single procedure, whereas adults required multiple procedures. These elephant castration procedures were difficult and it was not uncommon for incisions to break down and heal by second intention. An abdominal exploratory and ovariectomy has been reported in an Indian one-horned rhinoceros, but the animal died 48 hours after the surgery.11
Abdominal surgery in the elephant and rhinoceros is difficult for several reasons, the first being the animal’s overall size and how it affects the surgeon’s ability to reach and manipulate organs. Second, there is considerable thickness to the skin and body wall, which requires larger incisions and an inordinate amount of time for closure. Surgical sites may also be predisposed to dehisce and break down.2,12 An additional complicating anatomic variation in elephants is their peritoneum. Unlike most other mammal species, the peritoneum is covered by a fibroelastic layer and is itself redundant and only loosely attached to the body wall.5 For this reason, entering the peritoneal cavity of elephants, even after making an incision through the dermis and associated muscle layers, may be very challenging. Finding a route to and through the peritoneum is much more of an issue when animals are in lateral recumbency (versus standing), when there is less tension on the peritoneum. Rigid laparoscopy, or minimally invasive surgery (MIS), offers a variety of advantages over traditional surgical procedures. In humans and animals, MIS has been shown to be less painful, requires less healing time, allows faster return to normal function, and has less chance for infection.19 For the elephant and rhinoceros, MIS has these advantages and thus makes abdominal surgery a realistic and much less risky procedure. Laparoscopic abdominal surgeries have been successfully performed in the African elephant, white rhinoceros, and black rhinoceros.6,13,15–17 Procedures have included abdominal exploration with diagnostic sampling and a variety of reproductive surgical techniques.
Abdominal laparoscopic surgery in elephants is best accomplished in a standing position, either with the animal sedated and in a restraint device or under general anesthesia, with the animal in a standing position while being suspended from a crane truck.6,15–17 Using MIS and maintaining the elephant in a standing position allows for small incisions, rapid access to the abdominal cavity, and excellent overall surgical success.7 In captive situations, in which sedation may be used along with some degree of manual restraint, abdominal laparoscopic surgery may be readily accomplished. We have successfully used butorphenol and detomidine in conjunction with local analgesic nerve blocks with the elephant in a restraint chute (Fig. 68-1). The patient is sedated to the level at which it cannot lift its trunk and maintains a wide stance on all four legs, but is not likely to lie down. Once sedated, a regional analgesic block is accomplished using a 5-inch, 18-gauge spinal needle. In elephants, an elevated platform is used to place the surgeons at the level of the paralumbar fossa. This standing sedation approach has been used for abdominal exploratory and reproductive procedures in both adult elephants and rhinoceroses.
Figure 68-1 Standing sedation being used in an elephant chute for laparoscopic abdominal exploratory in a female African elephant. The surgeons’ and associated equipment are on an elevated platform that provides access to the paralumbar fossa. The rigid laparoscope has been placed inside the elephant’s abdomen. The surgeons are wearing video goggles, which are attached to the laparoscope camera unit and provide direct image viewing. These goggles significantly reduce glare issues when working outside in sunlight and allow both surgeons the same view without limitations of head position or monitor placement.
In free-ranging elephants, for which restraint facilities do not exist and the location of the patient is difficult to predict, the animals are placed under general anesthesia via a remote injection system. Once the patient is laterally recumbent, large padded straps or ropes (5-ton capacity with foam or wool padding) are placed around the proximal base of each leg and connected to the hook of a crane truck. These ropes are looped around the axilla or inguinal areas, ensuring limited pressure on the thoracic or abdominal cavities (Fig. 68-2). Limited pressure on the thorax greatly improves respiration and limited pressure on the abdominal cavity assists in insufflation and laparoscopic visibility. Once the ropes have been placed around each leg and secured to the crane, the elephant is lifted into a standing position. An additional rope is placed around the base of the tusks and attached with the other ropes so that the head is held in a normal upright position. In most cases, these animals are intubated to facilitate assisted ventilation when insufflation is applied.
Figure 68-2 An anesthetized free-ranging bull elephant in South Africa undergoing laparoscopic surgery. Five-ton capacity ropes are used to suspend the animal from a crane truck in an upright standing position. The elephant has been intubated and is being provided with assisted ventilation. A rigid operating laparoscope has been placed into the abdominal cavity. The laparoscopic viewing monitor has been placed on the animal’s dorsum so that the sun is behind it and the unit has been modified with the addition of black side panels to reduce glare.
The nonlaparoscopic surgical instruments used for creating and closing the abdominal incisions are commonly available through veterinary surgical catalogues. In most cases, the large versions are used. The procedure benefits from two to four no. 8 surgical scalpel handles with no. 60 scalpel blades, and two to four long no. 4 scalpel handles with no. 22 scalpel blades. Elephant and rhinoceros skin is tough, dense, and thick, so many blades are generally used for a single incision. It is always better to have too many blades than not enough. Other instruments include penetrating towel clamps, large Mayo scissors, long needle holders, long thumb forceps, vulsellum forceps, wire needle holders, and wire cutters. Modified Finocetto rib spreaders are also used to distract the skin while making the primary incision (Fig. 68-3).
Figure 68-3 Skin incision made in the paralumbar fossa of an African elephant. Note the use of Finocetto rib spreaders to retract the skin margins and provide access and visibility to the underlying muscle layers. In larger animals, the blades of the rib spreaders will need to be lengthened to retract the entire body wall of the elephant. Once the laparoscope is placed into the abdomen and insufflation has begun, the rib spreaders are removed.
Laparoscopic surgical equipment for minimally invasive surgery in the megavertebrate species must be longer and stronger than traditional equipment. The telescope—a rigid laparoscope— should have at least an 80-cm working length for bull elephants younger than 20 years and for cow elephants. In larger bull elephants, a working length of 100 to 112 cm is helpful (Fig. 68-4). A traditional telescope may be used but, to reduce the number of portals necessary, an operating laparoscope is more useful. Specialty telescopes (Karl Storz Endoscopy, Tutlingen, Germany) with two light source input posts will improve the amount of light that may be delivered into a potentially large peritoneal space. Visibility may be difficult because of the size of the abdominal cavity and the amount of fat and bowel distension that may occur. Having an appropriate amount of light is important. In the rhinoceros, depending on the size of the animal and procedure being attempted, an equine telescope (Hopkins Telescope, Karl Storz Endoscopy, 10 mm × 57 cm, 30-degree angle) may be used.13
Figure 68-4 This 112-cm megavertebrate telescope (Karl Storz Endoscopy) has been developed for minimally invasive surgery in elephants and rhinoceros. This is an operating laparoscope, which has a 10-mm working channel for placement of laparoscopic instruments. The Techno Pack (Karl Storz Endoscopy) system is a self-contained, battery-operated light source, monitor, and camera. This system is easily transported in field situations. This is a halogen light system and a xenon light source may be required for optimum viewing in elephants.
Laparoscopic cannulas are designed to allow exchange of instrumentation with minimal loss of intra-abdominal pressure, thereby maintaining an operating space within the abdominal cavity. Traditional diameter cannulas with their associated instruments and telescopes may be used. However, they should be 50 cm long and have thicker walls than traditional cannulas. If a larger diameter telescope is used, a larger diameter cannula is helpful. At least one of the cannulas should have two high-volume, stopcocks installed to allow larger volumes of insufflation gas to be instilled into the abdomen. The second stopcock may be used to measure intra-abdominal pressure. When using a longer large-diameter cannula as described earlier, the cannula should be at least 75 cm long but may be 50 cm long if the shorter telescope is used. In general, a large- diameter (30 mm for introduction of an operating telescope) and a traditional diameter (11 mm for introduction of instruments) cannula are used. This combination allows two instruments for diagnostics and surgical procedures. A third cannula would be necessary if a nonoperating telescope is used.
Obturators (trochars) for megavertebrate laparoscopy are similar to those used in traditional surgery. Because the primary cannula is placed using an open technique, no obturator is needed for the telescope. When placing the accessory instrument portal, a conical obturator is the best choice. This portal is placed blindly, after the abdomen has been insufflated, but the surgeon must be careful to avoid trauma to the bowel or other structures when placing the sharp obturator. The cannula-obturator unit is advanced until it may be seen laparoscopically tenting the peritoneum. The obturator is then removed and a hooked scissors is used to cut through and penetrate the peritoneum under direct visualization.