Laparoscopic Ovariectomy and Ovariohysterectomy in Llamas and Alpacas

ENDOSCOPIC SURGERY

0749--0739/00 $15.00 + .00

LAPAROSCOPIC OVARIECTOMY AND OVARIOHYSTERECTOMY IN LLAMAS AND ALPACAS Elaine M. Carpenter, DVM, Dean A. Hendrickson, DVM, MS, and David E. Anderson, DVM, MS

Laparoscopy has been used for many years in sheep for surgical artificial insemination and in cattle for diagnostic and reproductive tract examination. Laparoscopic surgery of the equine reproductive tract has been well established in recent years with many different diagnostic and therapeutic modalities. 6, 11, 12, 18 With the introduction of improved instrumentation, insufflation, and light source equipment, operative laparoscopy has been re-energized as a tool for veterinary surgery. Laparoscopic techniques are generally accepted as being less invasive than the equivalent open techniques. The minimally invasive nature of laparoscopic techniques and the shorter convalescent periods have made these techniques increasingly popular for use in New World camelids (llamas and alpacas). This article outlines the instruments and steps needed to perform laparoscopic surgery on the female reproductive tract in llamas and alpacas. The instruments needed for laparoscopic ovariectomy and ovariohysterectomy include the following: • • • •

Video camera and monitor Light source Insufflator Teat cannula

From the Departments of Large Animal Surgery (EMC) and Clinical Sciences (DAH), Veterinary Teaching Hospital, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado; and College of Veterinary Medicine, Ohio State University, Columbus, Ohio (DEA)

VETERINARY CLINICS OF NORTH AMERICA: EQUINE PRACTICE VOLUME 16 • NUMBER 2 • AUGUST 2000

363

364

CARPENTER et al

• Three cannulas (trochar and sheath, 10 mm in diameter, 10 cm long) • One 5-mm reducer • Laparoscopic telescope (10 mm in diameter, rigid endoscope, 30-60 cm in length, 30° view) • Acute-angle claw graspers (10 mm) • Babcock forceps (10 mm) • Laparoscopic scissors (10 and 5 mm) • Laparoscopic ligaclip applier and titanium ligating clips • Two ligature loops (Endoloop, size 0 polydioxinone suture; Ethicon Endo-Surgery, Cincinnati, OH) • Surgical table that allows for Trendelenberg positioning Distention of the abdomen with gas (usually carbon dioxide) is necessary to allow for adequate exploration and viewing of the abdominal viscera. A teat cannula or Veress needle is used for insufflation of the abdomen and must be at least 4 cm in length to extend into the abdomen via the linea alba because of retroperitoneal fat deposits. A laparoscopic cannula is made of a trochar and a sheath. The trochar fits inside the sheath and is used to introduce the sheath into the insufflated abdomen. The sheath allows for insertion and removal of instruments from the abdomen without loss of insufflation. For the following procedures, we recommend a cannula that is 15 cm in length and 11 mm in diameter, with a pyramidal trochar. Alternatively, a blunt trochar may be used to minimize risk of visceral trauma. A 5-mm reducer is used for the introduction of instruments with a smaller diameter. The laparoscopic telescope that we recommend for these procedures is a rigid endoscope 54 cm in length and 10 mm in diameter, with an end angle of 30° (Karl Storz Veterinary Endoscopy-America, Goeleta, CA). Also available are shorter endoscopes; however, we have found that the longer endoscope allows the camera end of the instrument to be held well out of the way of the surgeon. This is especially true with dorsally recumbent procedures. A 150-W light source is adequate, but we have found that a 300-W xenon light source is superior. The brighter light source allows the surgeon to have a deeper field of view. The operating instruments required are the acute-angle claw graspers (10 mm), Babcock forceps (10 mm), tissue scissors (10 mm), and suture scissors (5 mm). These instruments should be 30 to 45 cm in length. Two acute-angle claw graspers make manipulation of the uterus easier. There are many different types of ligature materials available for ovariectomy and ovariohysterectomy. We recommend the Endoloop (size o PDS) or the hand-tied 4S modified Roeder knot (size 1 Maxon; Sherwood-Davis and Geck, St. Louis, MO) for ligation of the ovarian pedicle or the uterine stump. For ligation of the ovarian vessels, the use of ligating clips (Karl Storz Veterinary Endoscopy-America) with a laparoscopic applier is quick and effective. The final piece of equipment necessary for performing dorsally

LAPAROSCOPIC OVARIECTOMY AND OVARIOHYSTERECTOMY

365

recumbent procedures is a surgical table capable of a 30° declined position (Trendelenberg position, with head down and tail up). This can be accomplished with a hydraulic table, a hoist attached to one end of the table, or a table with a wedge-shaped patient mold. It has been reported that mild intra-abdominal insufflation with carbon dioxide can be used safely in llamas under general anesthesia. 8 ANATOMY AND PHYSIOLOGY

The uterus of the New World camelids is a bicornate uterus. The cervix is approximately 2 to 5 cm in length and 2 to 4 cm in diameter.3,16 The cervix, which contains two to three spirals or ring-like structures, relaxes with estrogen stimulation but does not readily open.3, 15 The uterine body is 2 to 4 cm in length and 2 to 4 cm in diameter.16 Because the two uterine horns are fused for 6 to 16 cm, the uterine body seems longer from the external perspective. 3 The uterine hom from the bifurcation to the tip is 8.5 to 15.0 cm in length with a diameter of 2 to 4 cm. 3,16 The left uterine hom is generally slightly larger than the right hom. The oviduct is 10 to 18 cm in length in the llama and 20 cm long in the alpaca, with a diameter of 3 mm. 3 The oviduct runs from the blunt tip of the uterine hom to the ovary within the mesosalpinx. The ovaries of llamas and alpacas usually contain many follicles that vary from 2 to 13 mm in diameter.3 The ovary is spherical to ellipsoid in shape and measures approximately 2 cm by 1 cm by 1 cm. 3,16 Camelids are induced ovulators, meaning that ovulation is induced by copulation. These animals do not have an estrous period; thus, follicles grow and regress in an overlapping wavelike pattern. Puberty is believed to occur when the animal is approximately 10 to 12 months old.3,16 A 7- to 9-mm diameter follicle is considered to be mature; however, follicles greater than 13 mm in diameter are considered to be pathologic by some investigators.3 TECHNIQUE Dorsally Recumbent Ovariectomy and Ovariohysterectomy

Preoperative Preparation

Preoperative preparation consists of a physical examination, complete blood cell count, and selected blood chemistry analysis. A modified Lee-White clotting time may be estimated by observing the time required for clotting in the serum collection tube. 9 The patient needs to be held off feed for 24 to 48 hours and held off water for 12 hours. Fasting for 48 hours is preferred to decrease the amount of intestinal filling, which can obscure the view of the abdomen. The use of preoperative antibiotics

366

CARPENTER et

ru

is variable; however, the authors have not observed infections after approximately 200 laparoscopic procedures in camelids. A 14- or 16gauge intravenous catheter is placed in the right jugular vein in preparation for general anesthesia. Induction for general anesthesia can be accomplished with intravenous administration of ketamine (4.4 mg/kg) and diazepam (0.2 mg/ kg). An endotracheal tube is then placed, and anesthesia is maintained with isoflurane. lO The llama or alpaca is then placed in dorsal recumbency, and the ventrum is clipped and prepared from the xyphoid to the pubis. A rope or band around the chest attached to the table can help to prevent slippage during Trendelenberg positioning. Approach

A l-cm skin incision is made on the ventral midline through the umbilicus. A small stab incision can then be made through the linea alba. A teat cannula is inserted into the abdominal cavity. Care must be taken to ensure that the cannula is in the abdominal cavity so as to prevent extra-abdominal insufflation. This can be accomplished using multiple tests. When the teat cannula is in the abdominal cavity, it can be easily moved in a craniocaudal or lateral direction. Another test is to inject saline and evaluate the ease of injection. It should inject easily if the teat cannula is in the abdomen. Insufflation tubing is then attached to the teat cannula, and the abdomen is insufflated to 15 to 20 mm Hg. Once proper intra-abdominal pressure is achieved, the teat cannula is removed, and a cannula (pyramidal trochar and sheath) is inserted into the umbilical incision. A cannula 10 to 12 mm in diameter and 10 to 20 cm long may be used. Using careful controlled pressure with a twisting motion during insertion of the cannula can help to avoid inadvertent damage to abdominal viscera. An alternative approach to ensure that visceral penetration is avoided is the open technique with a blunt trochar. With this approach, a small incision (slightly smaller than the cannula) is created with a scalpel blade. This incision penetrates the parietal peritoneum and opens the abdominal cavity. A cannula with a blunt trochar can then be inserted, reducing the risk of penetrating the viscera. Guarded trochars are available that can make insertion safer; however, most are disposable and cost-prohibitive. The trochar is then removed, and the laparoscopic telescope is inserted. The insufflation tubing can be attached to the cannula to maintain abdominal distention. The patient is placed in the Trendelenberg position, that is, tilted with head down to move the abdominal viscera craniad. Exploration of the caudal abdomen should reveal the ovaries and uterus (Fig. 1).19 Instrument portals can then be created. The approximate location of these portals is 10 cm caudal to the umbilicus and 4 cm lateral on each side of midline (Fig. 2).7 Accurate placement can be accomplished by using digital pressure externally and observing with the laparoscope to identify the best location for the portals. Cannulas can be inserted into each of these portals using a technique similar to that used for the first

LAPAROSCOPIC OVARIECTOMY AND OVARIOHYSTERECTOMY

367

Figure 1. Parts of the llama uterus.

cannula while observing with the laparoscope (Fig. 3). Babcock forceps can be inserted into one of the instrument portals to move bowel and assist with the abdominal exploratory examination. Ovariectomy

Once the right ovary has been identified, acute-angle claw graspers are passed through the right portal. A ligature loop is passed through a 5-mm reducer placed in the left cannula. The claw graspers are passed through the ligature loop, and the right ovary is then grasped. The loop is passed around the ovary and tightened around the ovarian pedicle (Fig. 4). In larger animals such as the horse, it is thought that to obtain adequate ligation, the pedicle must be reduced in size by transecting any nonvascular tissue. 4 Because of the small size of the llama and alpaca pedicle, we have not found this procedure necessary. The 5-mm scissors are inserted into the left portal, and the tail of the ligature is transected. The lO-mm laparoscopic scissors can then be inserted into the left portal and used to transect the ovarian pedicle. The pedicle is observed for adequate ligation. If ligation is not adequate, a second loop can be placed at this time. The right ovary can be removed via the right portal. The left ovary is then identified, ligated, and removed in a similar manner. Ovariohysterectomy

Once the ovaries and uterus have been identified, ligation of the ovarian vessels can begin. The right ovary can be grasped using acute-

368

CARPENTER et al

Figure 2. Placement of cannulas in dorsal recumbency.

angle claw graspers inserted through the right portal. The mesovarium is exposed, and a ligaclip applier is inserted into the left portal. A clip is placed on the cranial edge of the mesovarium (Fig. 5). The ligaclip applier is removed, and IO-mm scissors are placed into the left portal and used to cut the mesovarium adjacent to the clip. This procedure is repeated until the ovarian vessels are ligated. We have found that three ligaclips are needed for secure ligation. The remainder of the mesovarium and broad ligament can then be transected using the tissue scissors. The uterus may need to be manipulated with the acute claw graspers during this procedure to expose the broad ligament for transection. Caution must be taken when considering the use of claw graspers when

Figure 3. Penetration of the trochar through the peritoneum from the internal perspective.

LAPAROSCOPIC OVARIECTOMY AND OVARIOHYSTERECTOMY

369

Figure 4. Ligation of the ovary with a ligature loop during ovariectomy.

working with a pyometra. The broad ligament is transected close to the uterine horns but not close enough to cut the uterine artery, which runs parallel to the uterus in the broad ligament. The broad ligament is cut caudal to the uterine body (Fig. 6). The same procedure is repeated for the opposite ovary and broad ligament. A ligature loop is then introduced into the abdomen through the left portal. The graspers are passed through the loop, and the right ovary and uterine hom are pulled through the loop. Once the right ovary and uterine hom are pulled through, the left ovary and uterine hom are manipulated through the loop. The ligature is then manipulated to the level of the uterine body (Fig. 7). Care must be taken to avoid including other abdominal structures such as small intestine or ureter in the ligature loop. The ligature is then tightened and the free end of the suture is transected with the 5-mm scissors. A second loop is placed on the uterine body using a similar technique. It is recommended that a

Figure 5. Application of ligation clips using a laparoscopic applier. The clips are being applied to the ovarian vessels.

370

CARPENTER et al

Figure 6. Locations shown are for ligature clips on the vasculature (A); broad ligament (B); ligatures on the body (C); and uterine body transection (D).

third loop be left on the portion of the uterus to be removed when excising a pyometra so as to reduce spillage of uterine contents during removal. Once the ligatures are placed, the uterus can be transected (Fig. 8). The lO-mm tissue scissors are used to transect the uterus, and the pedicle is observed for adequate ligation. The uterus can then be removed by enlarging the instrument portal (Fig. 9). The pneumoabdomen is reduced before closure of the incisions by opening the cannulas. Standing Ovariectomy

A standing ovariectomy may be performed in llamas sedated (0.1 mg/kg of butorphanol tartrate administered intravenously) and placed

Figure 7. Application of the ligature loop around the body of the uterus during ovariohysterectomy.

LAPAROSCOPIC OVARIECTOMY AND OVARIOHYSTERECTOMY

371

Figure 8. Transection of the uterine body distal to the ligature loops.

in stocks (Fig. 10). Unlike llamas, alpacas rarely remain standing during laparoscopy. Alpacas respond to stressful handling by lying down in sternal recumbency. As a result, ovariectomy is performed in alpacas with the female animal positioned in sternal recumbency. Sedation and rope restraint are used to maintain a sternal position. If necessary, the alpaca may be laid in lateral recumbency, but this positioning limits exposure to a single ovary. The left paralumbar fossa is clipped, blocked with 2% lidocaine hydrochloride, and surgically prepared. The block can be an inverted L-block or a series of local blocks that correspond to the portal locations. Caution should be exercised to limit the amount of

Figure 9. Excised llama uterus.

372

CARPENTER et al

Figure 10. Standing llama ready for ovariectomy.

lidocaine used. Lidocaine toxicity has been observed in llamas and alpacas. The location of the telescopic portal is approximately 4.5 cm caudal to the twelfth rib and 8 cm ventral to the transverse processes of the lumbar vertebrae. The abdomen can be insufflated using a teat cannula, and an insufflation device can be placed through a l-cm skin incision at the telescopic portal location? Once the abdomen is insufflated, the laparoscopic portals can be created in the paralumbar fossa in the same manner as described for the recumbent technique. Three portals are necessary to perform this technique: one telescopic portal and two instrument portals. The two instrument portals are located ventral (2 and 7 em) to the telescopic portal and caudal (6 and 10 cm) to the twelfth rib (Fig. 11).7 Usually, the entire procedure can be performed through the left flank using the same procedure as described for the dorsally recumbent ovariectomy. Bilateral flank laparoscopy has been used in alpacas, however, because of poor visibility, probably owing to sternal recumbency. Poor visibility also may be caused by a distended urinary bladder. Closure

The linea alba and sheath of the external abdominal oblique muscle can be closed with an absorbable suture such as size 0 polyglyconate placed in a cruciate pattern. Subcutaneous tissue can be closed using a

LAPAROSCOPIC OVARIECTOMY AND OVARIOHYSTERECTOMY

373

Figure 11. Location of cannulas for the standing flank procedure.

smaller absorbable material such as size 2-0 polyglyconate with a simple continuous pattern. Skin closure is optional and may be dictated by the disposition of the patient. CONCLUSIONS

Ovariectomy and ovariohysterectomy have become more commonly performed in domestic New World camelids. With the growing role of these animals as companions, commingling pet male and female llamas and alpacas has become relatively common. In large herds, neutering is used as a means of controlling breeding. Pyometra, neoplasia, and endometritis are examples of pathologic conditions that can be treated via ovariohysterectomy.17 More specific pathologic problems diagnosed and treated by laparoscopy include follicular cysts, cystic corpora lutea, ovarian tumors, hydrosalpinx, ovarian abscesses, paraovarian cysts, pyometra, mucometra, and segmental hypoplasia.1O, 18 Sumar and Adams16 report using laparoscopy in New World camelids to make observations of the reproductive tract (e.g., follicular activity before and after breeding, time of ovulation, corpus luteum formation and regression, early embryonic death, failure of ovulation). There have been few complications reported with laparoscopic ovariectomy or ovariohysterectomy in the New World camelids.7, 10, 16

374

CARPENTER et al

Potential complications include vascular pedicle hemorrhage, infection, inadvertent ligation of abdominal viscera, retroperitoneal placement of insufflation or laparoscope, visceral trauma, or inadequate viewing because of intestinal filling. Postoperative pain has not been reported as a complication in llamas or alpacas after ovariectomy or ovariohysterectomy. One author reports the inadvertent ligation of a ureter in one alpaca. These complications are considered to be rare when compared with those of traditional laparotomy. Also, the risk of incisional hernia is rare after laparoscopy. Good surgical technique can help to prevent many of the possible complications mentioned here. The authors have been able to perform the recumbent ovariectomy procedure in an average time of 35 minutes. Laparoscopy is a skill that must be learned through practice and can be somewhat frustrating in the early stages. There are some important points that can help to make this experience more enjoyable. There is little more frustrating to a laparoscopist than having distended or gas-filled abdominal viscera obscure the view. Fasting the animals for 48 hours can not only help to decrease intestinal filling but may also help to decrease intestinal gas accumulation, which can also obscure visibility. The authors have not observed complications of this fasting time in llamas or alpacas. Using a surgery table that can accommodate acceptable Trendelenberg positioning (30°) also assists in locating and working with the ovaries and uterus. If the uterus or ovaries are enlarged, a hand-tied ligature loop may be needed to make a loop large enough to pass around the enlarged structures. The larger loops tend to lose their shape and become difficult to work with if they are not made from sufficiently large suture material. With practice, the techniques described for ovariectomy and ovariohysterectomy can be mastered, and the techniques described here can be performed with increasing ease. References 1. Anderson DE, Gaughan EM, Baird AN, et al: Laparoscopic surgical approach and anatomy of the abdomen in llamas. JAVMA 208:111-115, 1996 2. Boure L, Marcoux M, Laverty S: Paralumbar fossa laparoscopic ovariectomy in horses with the use of Endoloop ligatures. Vet Surg 26:478-483, 1997 3. Fowler ME: Reproduction. In Medicine and Surgery of South American Camelids. Iowa City, lA, Iowa State University Press, 1998 4. Hanson CA, Galuppo LD: Bilateral laparoscopic ovariectomy in standing mares: 22 cases. Vet Surg 28:102-112, 1999 5. Hendrickson DA, Wilson DG: Instrumentation and techniques for laparoscopic and thorascopic surgery in the horse. Vet Clin North Am Equine Pract 12:235-259, 1996 6. Hendrickson DA, Wilson DG: Laparoscopic cryptorchid castration in standing horses. Vet Surg 26:335-339, 1997 7. King MR, Hendrickson DA, Southwood LL, et al: Laparoscopic ovariectomy in 2 standing llamas. JAVMA 213:523-525, 1998 8. Lin HC, Baird AN, Pough DG, et al: Effects of carbon dioxide insufflation combined with changes in body position on blood gas and acid base status in anesthetized llamas (Llama glama). Vet Surg 26:440--450, 1997 9. Lumsden JH: Basic hematology. In Davidson M (ed): Manual of Small Animal Clinical Pathology. Cheltenham, British Small Animal Veterinary Association, 1998, pp 34-60

LAPAROSCOPIC OVARIECfOMY AND OVARIOHYSTERECfOMY

375

10. Morrow CK, Barrington GM, Johnson LW, et al: How to perform laparoscopic ovariectomy in llamas and alpacas. Vet Med (Praha) 93:295-298,1998 11. Ragle CA, Schneider RK: Ventral abdominal approach for laparoscopic ovariectomy in horses. Vet Surg 24:492-497, 1995 12. Ragle CA, Schneider RK, Southwood LL: Abdominallaparoscopy in horses. Compend Contin Educ Pract Vet 18:1231-1239, 1996 13. Rodgerson DH, Baird AN, Lin He, et al: Ventral abdominal approach for laparoscopic ovariectomy in llamas. Vet Surg 27:331-336, 1998 14. Sanfran DB, Orlando R: Physiologic effects of pneumoperitoneum. Am J Surg 167:281285, 1994 15. Sumar J, Bravo PW: In situ observation of the ovaries of llamas and alpacas by use of a laparoscopic technique. JAVMA 199:1159-1162, 1991 16. Sumar J, Adams GP: Reproductive anatomy and physiology of the female llama. In Youngquist RS (ed): Current Therapy in Large Animal Theriogenology. Philadelphia, WB Saunders, 1997, pp 792-798 17. Turner AS: Surgical conditions in the llama. Vet Clin North Am Food Anim Pract 10:81-99, 1994 18. Wilson DG: Surgery of the genitalia of llamas. In Youngquist RS (ed): Current Therapy in Large Animal Theriogenology. Philadelphia, WB Saunders, 1997, p 842 19. Wilson GL: Laparoscopic examination of the reproductive tract of the mare. In Morrow DA (ed): Current Therapy in Theriogenology, ed 2. Philadelphia, WB Saunders, 1986, pp 840-843 20. Yarbrough TB, Snyder JR, Harmon FA: Laparoscopic anatomy of the llama abdomen. Vet Surg 24:244-249, 1995 Address reprint requests to

Elaine M. Carpenter, DVM Department of Large Animal Surgery Veterinary Teaching Hospital College of Veterinary Medicine and Biomedical Sciences Colorado State University 300 West Drake Road Fort Collins, CO 80523-1620