Ebook Advances in equine laparoscopy: Part 2

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Part 1 book "Advances in equine laparoscopy" includes content: Bilateral ovariectomy in the mare, ovariectomy for the removal of large pathologic ovaries in mares, imbrication of the mesometrium to restore normal, horizontal orientation of the uterus in the mare, nephrectomy, repair of the ruptured equine bladder, equine thoracoscopy, general anesthesia in the recumbent horse,.... and other contents.

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17 Claude A. Ragle Bilateral Ovariectomy in the Mare Key Points Dykstra 1919). Laparotomy is the described surgi- cal approach for ovariectomy in these early record- • Laparoscopic ovariectomy offers excellent ings. Enough controversy was generated by the viewing, complete hemostasis, tension-free technique related to “dangerous consequences” tissue handling, and small incisions. and effects on horse breeding that in 1717, France • Ovariectomy is useful for treating behavioral passed a law to restrict the practice to “special problems in mares directly attributable to the cases” (Fleming 1881; MacQueen 1895). Charlier estrous cycle and to prevent reproduction. of France introduced the technique of mare castra- • Prior attainment of fundamental and technique- tion via the vaginal approach in 1850 (MacQueen specific laparoscopic skills is required before 1895; Hobday 1900). This approach rapidly gained performing the operation. favor and is described in widely available surgery • Careful preoperative preparations and client texts at least since 1903 (Williams 1903). communication are important for successful From these times to the present, ovariectomy outcomes. has been implemented on a very minor scale com- • Approximately 80% of mares treated for pared to castration of the male horse. In spite of estrous behavior problems will improve, while the stark differences in the frequency of applica- about 30% will continue displaying some signs tion between the equine genders, the major goals of estrous associated behavior. of the operations are similar: permanent behavior modification and elimination of reproduction. Two obvious differences between the genders, Introduction behavior and anatomy, account for the disparity in the operations. Intact mares are not as difficult Ovariectomy of the mare has a long history that is or dangerous to house and handle as intact stal- traceable to at least the seventeenth century (Mac- lions, and the external location of testicles permit Queen 1895; Hobday 1900; Schnoenleber & much easier access for removal. Few colts are kept Advances in Equine Laparoscopy, First Edition. Edited by Claude A. Ragle. © 2012 by John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc. 177
178 Advances in Equine Laparoscopy intact as breeding stallions, whereas nearly all ovariectomy is its use in the management of mares fillies remain intact and are considered potential with chronic pyometra and/or endometritis that broodmares. This is in part due to the previous have been resistant to routine treatments (M. lack of minimally invasive surgical options for LeBlanc, pers. comm.). ovariectomy. Until the application of laparoscopy It should be appreciated that the mare differs to ovariectomy, many owners and veterinarians from other domestic species in that estrogen does considered the available operative techniques too not seem to be required for at least some degree invasive and flawed for use except when surgery of estrous behavior. The most determining hor- was a last resort to salvage a problem mare (Jor- monal factor in estrous behavior in the mare seems gensen 1996). Of 800 equine practitioners that to be the absence of progesterone (Asa et al. responded to a survey regarding the effects of the 1980a,b). Ovariectomy removes the ovarian source estrous cycle on athletic performance, 89% had of progesterone and estrogen. It is common for treated mares for variation in performance during ovariectomized mares to be used as jump mares estrus (Jorgensen et al. 1996). for collecting stallions with or without supple- Case selection for bilateral ovariectomy in the mentation of estrogen (Brinsko et al. 2010). Con- mare requires clear communication with the sidering these observations, it is important to note owner with regard to expected outcomes. Although that published reports of postovariectomy mares ovariectomy to prevent reproduction is completely operated for behavior problems related to estrus effective, other surgical options (e.g., oviduct liga- indicate that only about 30% of mares are noticed tion) are available if permanent prevention of to manifest some signs of estrus (Hooper et al. pregnancy is the only goal (McCue et al. 2000). 1993). It has been stated that when used for semen When a mare is presented for operation with the collection, ovariectomized mares rarely need complaint of behavior problems, confirming the exogenous hormonal therapy to display behav- behavior’s association with the estrous cycle is ioral signs of estrus (Brinsko et al. 2010). It is also important. Publications that examine the effects of important to note that ovariectomized mares, as the estrous cycle on the athletic mare are useful for well as intact mares, can exhibit “paradoxical reviewing and sharing to aid owners in making estrous” behavior during seasonal anestrus that is informed decisions regarding their mare (Jor- associated with hormone secretion from the gensen et al. 1996; Pryor & Tibary 2005). Mare adrenal cortex (Crowell-Davis 2007). Despite these behavior issues can be a complex problem with apparent contradicting facts, owner satisfaction factors involved other than the estrous cycle. surveys of mares ovariectomized for “behavior Mental attitude problems of mares unrelated to problems during estrus” report that approxi- estrus are not improved by ovariectomy. mately 80% are satisfied with the outcome of the Some mares and female mules (mollies) are pre- operation (Hooper et al. 1993; Hanson & Galuppo sented for surgery not due to abnormal behavior 1998; Kamm & Hendrickson 2007; Smith & Mair but for the intent to promote a more “gelding-like” 2008). animal. There are owners who elect to spay mares The problem behaviors associated with estrus intended solely for a riding career from the belief that most improve following ovariectomy are that it will provide a more docile horse that is aggressive behavior and a generalized disagree- easier to manage around other horses. This prac- able demeanor; excitability, kicking, and biting; tice is common in some regions and in the United and problems during training (Kamm & Hen- States can be traced back to at least the 1900s drickson 2007). The time frame during which (Hobday 1900). However, there is no scientific improvement is noted ranges from 3 to 18 months. study that examines the opinion that the spayed Laparoscopic bilateral ovariectomy offers sig- mare makes a better riding horse than the intact nificant advantages over previous techniques via mare. colpotomy (vaginal celiotomy), laparotomy, and There are also reports of a few mares being ventral celiotomy (Kamm & Hendrickson 2007). treated by ovariectomy to eliminate signs of colic Inherent in the laparoscopic approach is providing associated with ovulation (Hanson & Galuppo clear viewing of the target tissues, ability to 1998). An indication suggested for bilateral manipulate the ovary without undue tension on
Bilateral Ovariectomy in the Mare 179 the pedicle, excellent hemostasis, and small inci- of about 200 L of ingesta (Kararli 1995). The weight sions. This combination of technical advantages is of the gastrointestinal contents will range from 5% not possible with the nonlaparoscopic techniques to 10% of the body weight depending on the diet of ovariectomy. Laparoscopic ovariectomy per- composition (5% with concentrate and 10% with formed in the standing horse presents technical roughage) (Harris et al. 2006). Intestinal transit advantages over the technique performed in the time, or mean retention time, of feedstuffs in recumbent horse. Foremost is that the mesovar- horses varies in studies from 18 to 60 hours ium and ovary as suspended in the standing horse depending on methodology of measurement, diet, are much easier to locate and manipulate as com- level of exercise, and so on (Van Weyenberg et al. pared to the passively positioned reproductive 2006). For clinical application, it is considered that tract of the mare positioned in dorsal recumbency. 45–72 hours are required for food to completely The dorsal positioning requires specific instru- pass through the digestive tract of the horse ment manipulation to elevate the uterine horn to (Swinker 2002). The goal is that prior to surgery, localize the ovary and requires a second instru- the horse should be concave in the paralumbar ment for grasping it and for applying traction fossae. Observing the concave shape in the flanks during sectioning of the pedicle (Ragle & Sch- and a low intestinal bulk detected during transrec- neider 1995). tal exam are the best indicators that the operation Contraindications for standing elective bilateral can proceed. Depending on the horse, the time to laparoscopic ovariectomy are few and similar to achieve this can vary from 12 to 72 hours. The any elective laparoscopic procedure performed on alternative to complete feed withdrawal is to the standing horse. The horse should be of correct restrict feed to a low bulk, high energy diet (e.g., size and training to allow safe restraint in standing 1 cup of soaked complete pelleted feed with ¼ cup stocks. It is preferable to perform the operation corn oil four times a day) until there is a concaved when the mare is in diestrus or anestrus. Perform- contour to the paralumbar fossae (∼48 hours). ing the operation while the mare is in estrus The greater the internal body fat, the more should be avoided. Although it seems intuitive important it is to reduce the contents in the gas- that ovariectomy of mares with “behavior prob- trointestinal tract. Excess internal body fat has a lems during estrus” would be more successful in significant negative impact on the size of the lapa- younger mares, at least one study indicates that roscopic visual field and in the ease of establishing the age at ovariectomy did not significantly affect and maneuvering laparoscopic portals (Figure the outcome (Kamm & Hendrickson 2007). 17.1). Although the body condition score may be Anesthesia, positioning, and surgical preparation Normal preoperative screening prior to surgery is standard. Horses that present with no significant current or past illness receive a physical exam, including a rebreathing exam and an electrocar- diogram. Complete blood count with packed cell volume (PCV) and total protein (TP) is usually performed, although a PCV and TP are adequate in a young healthy horse. In the majority of horses, it is advisable to reduce the intestinal contents prior to surgery to improve intraoperative viewing. The preoperative diet is modified by feed with- drawal or feeding a high energy, low bulk diet. Figure 17.1 Excess internal body fat reduces the portal’s Water is not restricted prior to surgery. A 450-kg range of motion and increases the tissue disruption horse will have a digestive tract volume capacity surrounding the portal.
180 Advances in Equine Laparoscopy prepared for surgery with chlorhexidine surgical scrub solution alternated with sterile gauze soaked in saline (0.9% NaCl) solution. The rectum is man- ually evacuated and a urinary catheter is asepti- cally placed for the duration of the operation. Instrumentation 1 57-cm 30° laparoscopic telescope 1 Video camera, monitor, light source, insufflator 1 5-mm, 32-cm, 18-ga tip laparoscopic injection needle 2 5- to 12-mm laparoscopic cannula Figure 17.2 A mare with excessive internal body fat. Fat is bulging from the paralumbar fossa and the mesocolon. assemblies 2 10-mm laparoscopic cannula assemblies 1 5- or 10-mm traumatic grasping forceps one indicator of possible excess internal body fat, 1 10-mm vessel-sealing device (LigaSure) some horses seem to have greater internal body fat 1 Morcellator (especially in the retroperitoneal area of the para- Items to have available lumbar fossae, mesocolon, and mesovarium) than their amount of subcutaneous fat would suggest – Ligating loops (Figure 17.2). Transrectal examination is per- – Hemoclips formed prior to surgery to evacuate the rectum, – Staples to confirm the reproductive tract status, and to – Semm claw forceps verify that the paralumbar fossa area is clear of – Specimen bag any obstructions that would complicate portal – 10-mm × 20-cm laparoscopic cannula assemblies placement. – 5-mm laparoscopic scissors Mares that are anticipated to be nervous in the stocks prior to surgery are premedicated with acepromazine at about 0.03–0.06 mg/kg IM 30 Surgery minutes prior to loading into the stocks. Before laparoscopy, the horse is administered penicillin G The primary task of the operation is to achieve potassium (22,000 U/kg [10,000 U/lb], IV), genta- excellent hemostasis during transection of the micin sulfate (6.6 mg/kg [3 mg/lb], IV), and flu- ovarian pedicle (Figure 17.3) and removal of the nixin meglumine (1.1 mg/kg [0.045 mg/lb], IV). ovary from the abdominal cavity. Practically every The horse is led into a standing operating room, method available for use in operations has been restrained in stocks, and positioned to gain access applied to ovariectomy of the horse. An excellent to the paralumbar fossae. Extra stall mats can be review of these has been published (Lee & Hen- stacked at the rear of the stocks to achieve a 10- to drickson 2008; Shettko & Hendrickson 2008). This 12-cm elevation of the pelvis to aid viewing of the surgical description will focus on a two-portal caudal abdomen. Detomidine hydrochloride technique utilizing vessel-sealing technology and (0.015 mg/kg [0.0068 mg/lb], IV) and butorphanol morcellation. tartrate (0.025 mg/kg [0.011 mg/lb], IV) are admin- After draping the surgical areas, 2% mepiva- istered. Sedation is maintained with detomidine caine hydrochloride (20–40 mL) is infiltrated hydrochloride continuous rate infusion (CRI) and throughout the full thickness of the body wall adjusted as needed (0.1 mg/kg/min). The hair with special attention to the skin at each of the over the caudal thorax, paralumbar fossae, and four portal sites. Intradermal injection of the local caudal flanks are clipped, and the sites are anesthetic is performed, creating a 3- to 5-cm
Bilateral Ovariectomy in the Mare 181 Figure 17.3 The ovarian artery is tortuous and may be cleaved several times when transected. Figure 17.5 Sites of local anesthetic injection for portals and drape attachment. Portal Site Figure 17.4 Local anesthetic injection creating a ∼5-cm intradermal wheal followed by deep infiltration to the peritoneum. Caudal Edge wheal over each portal site (Figure 17.4). An addi- of Pleural Cavity tional intradermal site can be injected at the ventral aspect of the drape fenestration to permit towel clamp application (Figure 17.5). On the mare’s left side, the first portal (laparo- scope) is located at the level of the ventral tuber coxae and between the last two ribs. To avoid pos- sible penetration of the pleural space, it is impor- tant that the intercostal portal is not located dorsal Figure 17.6 To avoid penetration of the left pleural cavity, to a horizontal line from the most ventral aspect a portal in the 17th intercostal space is placed below a of the tuber coxae (Figure 17.6). The second portal horizontal line from the most ventral aspect of the tuber coxae. (instruments) is located 5 cm below the dorsal margin of the internal abdominal oblique muscle 5 cm distal and caudal to the first portal. A 15-mm midway between the last rib and tuber coxae. On skin incision is made over the first portal location the right side, the first portal is located just dorsal on the left side. A 10- to 12-mm portal sheath with to the internal abdominal oblique muscle and just conical obturator is placed into the abdominal caudal to the last rib. The second portal is located cavity (Figure 17.7). The obturator is removed and
182 Advances in Equine Laparoscopy Figure 17.7 Depth of portal insertion to penetrate the peritoneum at the 17th intercostal space on a horse with normal internal body fat. Figure 17.8 Laparoscopic injection needle positioned to infiltrate the mesovarium of the left ovary. replaced with a 50-cm-long, 10-mm-diameter, 30° angle viewing laparoscope. Mansfield, MA) is inserted to begin the removal of If the field of view is not adequate, insufflation the ovary. The instrument is capable of both vessel is used. The amount of insufflation should be kept sealing and transection of the mesovarium with to the minimum amount to permit viewing. Not each placement of the jaws. The cutting function every horse will require the use of an insufflator is activated by a trigger on the instrument handle for adequate viewing of the ovarian pedicles. and should only be used when vessel sealing has When needed, the abdomen is insufflated with been successful, as indicated by visual assessment carbon dioxide (CO2) (7 L/min) for ∼4 minutes of tissue reaction to the energy source and the with adjustments as needed and then turned off, correct audible signal from the unit. The maximum the goal being to allow clear viewing of the ovarian length of tissue that the jaws will accommodate is area and to provide an intra-abdominal pressure 20 mm. Transection can begin at the cranial or below 10 mmHg. caudal aspect of the ovary. It is technically easier Once a field of view is established on the left to begin at the cranial aspect as the angle of side, the laparoscope is passed under the descend- approach is straight and the mesovarium is a ing colon at the level of the bladder and then single-layer structure with a free leading margin directed dorso-cranial, providing a view of the at that point as compared to the double-layer right paralumbar fossa area. A 15-mm skin inci- structure (proper ligament and mesosalpinx) at sion is made over the first portal site, and a 5- to the caudal attachments to the uterine horn. If the 12-mm sheath and obturator is inserted using the mare has excessive adipose tissue in the mesovar- laparoscopic view to confirm placement into the ium, extra caution should be taken to assure abdominal cavity. The second portal on the right hemostasis. When the pedicle becomes too thick is placed using an identical technique. The laparo- due to fat to allow secure closure of the handle, scope is withdrawn from under the descending the pedicle should be split sagittally using the jaws colon and focused on the intra-abdominal location of the vessel-sealing instrument. This will reduce of the paralumbar fossa for the second portal on the thickness of the tissue placed between the the left side; it again is placed under laparoscopic jaws, allow transection of the pedicle to progress, guidance to confirm cleanly entering the abdomi- and improve hemostasis. It is also possible to nal cavity. perform a double seal over the area of the ovarian After all four portal sheaths are established, a artery by placing the first grasps of the jaws more long injection needle is placed in the newly estab- dorsal on the mesovarium and releasing the jaws lished port and 30–60 mL of 2% lidocaine is infil- after sealing without triggering the scissors. The trated along the mesovarium of the ovary (Figure next placement of the jaws should be just ventral 17.8). The needle is withdrawn from the portal to the last seal, this time completing another and a vessel-sealing device (LigaSure, Covidien, sealing cycle and transecting. As the transection
Bilateral Ovariectomy in the Mare 183 Figure 17.9 A tag of mesovarium is preserved to suspend Figure 17.11 Tenaculum forceps provide a secure grasp of the ovary for morcellation. the ovary with complete closure of the jaws, reducing instrument interference during morcellation. portal in the paralumbar fossae. If the extra 5-mm portal is used, then the ovary can be suspended from the 5-mm forceps for morcellation. Once the ovary is freed from all but the small band of mes- ovarium, the vessel-sealing instrument and associ- ated portal are removed. The skin incision is slightly enlarged to accommodate the 15-mm diameter of the morcellator. The obturator is placed in the 15-cm insert length barrel of the mor- cellator, and the assembly is placed into the abdomen. The obturator is removed and a pair of 5- or 10-mm laparoscopic tenaculum forceps (Figure 17.11) is placed through the portal of the morcellator to grasp a leading edge of the ovary. Figure 17.10 Transection of the proper ligament of the ovary is important to prevent injury to the uterine horn The ovary is drawn to the morcellator, and the during morcellation. morcellator is activated either by foot pedal or handpiece, depending on the surgeon’s prefer- continues, a 5-mm band of attached mesovarium ence. The morcellator has a 12- to 13-mm blade should be preserved to suspend the ovary for mor- consisting of a rigid inner tube that rotates within cellation (Figure 17.9). Care should be taken to an outer tube. The blade connects to an electric transect the robust proper ligament of the ovary motor drive unit. When activated, the blade and not use that structure for suspending the extends 2–4 mm out beyond the tube except in a ovary for morcellation (Figure 17.10). There is risk small guarded area that extends from the outer of damage to the uterine horn by pulling it into tube to permit cutting via a peeling action. The the morcellator if the proper ligament of the ovary morcellator can also be set where the cutting blade remains attached to the ovary. If at anytime during is extended beyond the guard if a core cut is the operation an additional laparoscopic instru- needed. For morcellation of the ovary, the adjust- ment would augment the viewing and dissection able guard is used and set in the 6 o’clock position of the ovary, a 5-mm portal can be established. so it can be rotated as needed to aid in the process Depending on the individual anatomy of the of morcellation. It is important that excellent mare, the extra portal can be located approxi- viewing of the morcellation is maintained. If the mately 10 cm ventral or dorsal to the existing view becomes obscured, the morcellator blade
184 Advances in Equine Laparoscopy Figure 17.12 Gynecare Morcellex and morcellated tissue of one ovary. should be immediately disengaged until the view Figure 17.13 Hemostasis following complete resection of is reestablished. The ovary is extracted in peeled ovarian attachments. sections and, depending on the size, consistency, and configuration of the ovary, it can be removed in typically three to seven segments (Figure 17.12). The small band of mesovarium that suspends the ovary is cut by the blade of the morcellator as the final portion of suspended ovary is pulled into the portal and the portal is angled to transect the band as it is stretched over the blade edge. Alter- natively, the remaining piece of suspended ovary can be grasped with 5-mm tenaculum forceps, and a pair of 5-mm scissors can be placed alongside to cut the band. Any fragments of ovary that may become separated and free in the abdomen are Figure 17.14 Postoperative bandage of laparoscopic located and removed through the morcellator portals. portal. Although not a common practice in the horse, free transected ovaries have been left in the over the incisions before the horse is returned to abdomen with little apparent negative effect its stall (Figure 17.14). (Shoemaker et al. 2004). At the conclusion of the operation on the left side, a final check of the ovarian pedicle is performed to confirm hemosta- Postoperative management sis (Figure 17.13). The laparoscope and morcella- tor are then removed, and the operation is repeated Postoperatively, the horse is returned to its stall on the right side. and allowed food and water several hours after When the ovariectomy is completed, remaining surgery. Antibiotics are continued for 12 hours gas in the abdominal cavity is decompressed. postoperatively. The day after surgery, transrectal Suction can be used to aid in the removal of the palpation is performed to sweep the resected gas to more completely empty the abdomen to ovarian pedicles and to free any tissue that might reduce the occurrence of subcutaneous emphy- have become adhered. Non-steroidal anti- sema. The surgical site is cleaned of any signs of inflammatories are administered for 3–7 days after blood, and the skin incisions are apposed using surgery. Body temperature should be monitored at skin staples or size 2-0 or 0 monofilament nonab- least once per day for 3–4 days. The surgical inci- sorbable suture. Typically, there is no need to sions are kept bandaged and are monitored daily. suture the aponeurosis of the external abdominal Mild reaction to palpation over the portal sites oblique muscle. An adherent bandage is placed during the first 3–5 days is to be expected. If
Bilateral Ovariectomy in the Mare 185 (A) (B) Figure 17.15 Optical trocars allow the surgeon to place the port while the laparoscope is within the cannula, allowing visualization of the tissue as the trocar is advanced. (A) Clear tip cannula. (B) Threaded corkscrew cannula. pressurized insufflation was used during the space that degrades the field of view. If a sharp operation, the paralumbar area should be moni- trocar or a longer cannula is used, the peritoneum tored for subcutaneous crepitus. Owners should is penetrated, but the risk to underlying viscera be instructed on observation of the horse after during this blind placement is increased. The tech- release from the hospital and on how to recognize nique of placing a cannula with a blunt obturator subcutaneous crepitus as it is common when in the 17th intercostal space on the left is a method insufflation is used. Horses are confined to a stall to easily penetrate the peritoneum without dis- for 24 hours, and then hand-walked or allowed placing it. This is possible because the peritoneum small paddock turnout. Light riding can begin is tightly adhered to the ribs in this location. after staple or suture removal and then progress Although portals can be established in the 17th to full work over 2 weeks. intercostal space of the right side, the peritoneum is not adhered here as it is on the left. Even in using the left intercostal or optical trocar tech- Complications niques (Figure 17.15) care must be taken to only insert the obturator until it just penetrates the peri- There are several technical challenges in perform- toneum; over-advancing can cause blunt damage ing laparoscopic ovariectomy that can lead to to the spleen or kidney. During placement of the complications. At the top of the list would be the cannula, the obturator should be removed every challenge of establishing the laparoscopic portals. few centimeters advanced to check for the aspira- The risk of damage to internal organs (e.g., spleen, tion of air from the negative intra-abdominal pres- kidney, cecum, mesovarium, mesocolon, and sure. Once the intercostal portal is established, it descending colon) or failure to enter the peritoneal permits the remaining portals to be placed under cavity are the primary complications (Desmaizie direct viewing. If during direct viewing there is et al. 2003). Recognizing these concerns, cannula trouble with the obturator or the trocar penetrat- manufacturers have devised special laparoscopic ing the peritoneum, the “chopstick” maneuver can cannulas to aid in placement. The common feature be employed. The chopstick maneuver involves of these ports is that they permit placement while using an ipsilateral instrument or a laparoscope to the laparoscope is within the cannula for viewing alternately cross over the dorsal and ventral the tissue planes as the trocar is advanced. The aspects of the tip of the advancing cannula, thus peritoneum overlying the paralumbar fossae of pushing the peritoneum over the cannula from the horse is resistant to penetration and is easily inside the abdomen. displaced by a blunt obturator. This can lead to the Although there are a multitude of technical common length (15 cm) cannula being too short to errors that can occur during laparoscopic ovariec- enter the abdomen, creating a retroperitoneal tomy (e.g., dropping a freed ovary, thermal or
186 Advances in Equine Laparoscopy sharp damage to the adjacent viscera, inadequate Crowell-Davis, S.L. (2007) Sexual behavior of mares. hemostasis, poor field of view, and inability to Hormones and Behavior, 52, 12–17. efficiently manipulate instruments), it has still Desmaizie, L.M., Martinot, S., Lepage, O.M., et al. (2003) Complications associated with cannula insertion tech- been demonstrated to have fewer complications niques used for laparoscopy in standing horses. Vet- than previous techniques (Rocken et al. 2011). erinary Surgery, 32, 501–506. Fleming, G. (1881) Cryptorchidism, and the castration of cryptorchid horses. The Veterinary Journal and Annals of Comparative Pathology, 12, 147–148. Conclusion Hanson, C.A. & Galuppo, L.D. (1998) Bilateral laparo- scopic ovariectomy in standing mares. Proceedings of Bilateral laparoscopic ovariectomy offers many the American Association of Equine Practitioners, 44, pp. advantages over the previous techniques of bilat- 300–301. eral ovariectomy in the mare. Continued improve- Harris, P.A. (ed.), Coenen, M., Frape, D., et al. (2006) ments in technique and instrumentation will only Equine nutrition and metabolic diseases. In: The Equine Manual, 2nd ed. (ed. A.J. Higgins & J.R. Snyder), add to the efficacy, affordability, and operative p. 164. Saunders, London. benefits. Although primarily used to salvage Hobday, F.F. (1900) Oophorectomy or ovariotomy of the mares with behavioral problems during estrus mare. The Veterinary Journal, 1, 84–88. and to produce “jump” mares, additional indica- Hooper, R.N., Taylore, T.S., Varner, D.D., et al. (1993) tions are reported. Among these additional indica- Effects of bilateral ovariectomy via colpotomy in tions is the use of ovariectomy to improve the mares: 23 cases (1984–1990). Journal of the American consistency of performance as riding horses, to Veterinary Medical Association, 203, 1043–1046. Jorgensen, J.S. (1996) Effects of the estrous cycle on per- contribute to the reduction of unwanted and feral formance in athletic mares. Compendium on Continuing horse populations, and as a method for horse Education for the Practicing Veterinarian, 18, 692–699. breeders to gain greater control over the distribu- Jorgensen, J.S., Vivrette, S., Correa, M., et al. (1996) Sig- tion of their genetic breeding pool. nificance of the estrous cycle on athletic performance There is a dearth of research related to the effects in mares. 1996 Proceedings, 42nd Annual Meeting of bilateral ovariectomy on the overall behavior of the American Association of Equine Practitioners, pp. 98–100, Denver, CO, American Association of Equine and health of the mare. There has been little to no Practitioners. research effort evaluating the in-depth normal Kamm, J.L. & Hendrickson, D.A. (2007) Clients’ per- estrous behavior of the mare mule. Understanding spectives on the effects of laparoscopic ovariectomy what is normal both for a population and for an on equine behavior and medical problems. Journal of individual is a prerequisite for being able to Equine Veterinary Science, 27, 435–438. compare the effects of ovariectomy. Without Kararli, T.T. (1995) Comparison of the gastrointestinal doubt, it is a challenging area of study but one that anatomy, physiology, and biochemistry of humans and commonly used laboratory animals. Biopharma- could drastically improve the decision-making ceutics & Drug Disposition, 16, 366. process for laparoscopic bilateral ovariectomy in Lee, M. & Hendrickson, D. (2008) A review of equine the mare. standing laparoscopic ovariectomy. Journal of Equine Veterinary Science, 28, 105–111. MacQueen, J. (1895) Abdominal surgery. The Veterinary Journal and Annals of Comparative Pathology, 41, 296. References McCue, P.M., Hendrickson, D.A., & Hess, M.B. (2000) Fertility of mares after unilateral laparoscopic tubal Asa, C.S., Goldfoot, D.A., Garcia, M.C., et al. (1980a) ligation. Veterinary Surgery, 29, 543–545. Sexual behavior in ovariectomized and seasonally Pryor, P. & Tibary, A. (2005) Management of estrus in the anovulatory pony mares (Equus caballus). Hormones performance mare. Clinical Techniques in Equine Prac- and Behavior, 14, 46–54. tice, 4, 197–209. Asa, C.S., Goldfoot, D.A., Garcia, M.C., et al. (1980b) Ragle, C.A. & Schneider, R.K. (1995) Ventral abdominal Dexamethasone suppression of sexual behavior in the approach for laparascopic ovariectomy in horses. Vet- ovariectomized mare. Hormones and Behavior, 14, erinary Surgery, 24, 492–497. 55–64. Rocken, M., Mosel, G., Seyrek-Intas, K., et al. (2011) Uni- Brinsko, S.P., Blanchard, T.L., Varner, D.D., et al. (2010) lateral and bilateral laparoscopic ovariectomy in 157 Manual of Equine Reproduction, 3rd ed. Mosby, mares: a retrospective multicenter study. Veterinary St. Louis, MO. Surgery, 40(8), 1009–1014.
Bilateral Ovariectomy in the Mare 187 Schnoenleber, F.S. & Dykstra, R.R. (1919) Castration of Smith, L.J. & Mair, T.S. (2008) Unilateral and bilateral males and females. In: Castration of Domesticated laparoscopic ovariectomy of mares by electrocautery. Animals, pp. 1–3. Orange Judd Co., New York, New The Veterinary Record, 163(10), 297–300. York. Swinker, A. (2002) The Anatomy and Function of the Shettko, D.L. & Hendrickson, D.A. (2008) Principles of Horse’s Gastrointestinal Tract, http://www.das.psu laparoscopic hemostasis: ligation techniques. Journal .edu/research-extension/equine/news/the-anatomy of Equine Veterinary Science, 28(1), 46–50. -and-function-of-the-horse2019s Shoemaker, R.W., Read, E.K., Duke, T., et al. (2004) In Van Weyenberg, S., Sales, J., & Janssens, G.P.J. (2006) situ coagulation and transaction of the ovarian pedicle: Passage rate of digesta through the equine gastroin- an alternative to laparoscopic ovariectomy in juvenile testinal tract: a review. Livestock Science, 99(1), 3–12. horses. The Canadian Journal of Veterinary Research, 68, Williams, W.L. (1903) Surgical and Obstetrical Operations, 27–32. p. 97. Williams, Ithaca, NY.
18 Ovariectomy for the Removal of Large Pathologic Ovaries in Mares Hans Wilderjans Introduction nonlaparoscopic methods include hemorrhage, postoperative colic, seroma and hematoma forma- Unilateral or bilateral laparoscopic ovariectomy tion, shock, peritonitis, diarrhea, myositis, intesti- through ventral and standing lateral approaches nal adhesions, nerve paresis, incision line infection has been reported for the removal of both normal and dehiscence, and sudden death (Moll et al. and large pathologic ovaries in mares (Palmer 1987; Loesch & Rodgerson 2003; Embertson 2006). 1993, 2002; Ragle & Schneider 1995; Walmsley Difficulty in adequately exteriorizing the ovary in 1999; Rodgerson et al. 2002; De Bont et al. 2010; nonlaparoscopic approaches results in suboptimal Kummer et al. 2010). Colpotomy, flank, ventral observation of the mesovarium, with ligation, and diagonal paramedian, and ventral median electrocauterization, or stapling often occurring celiotomy approaches have been used (Moll et al. with the ovarian pedicle under maximum tension 1987; Hooper et al. 1993; Carson-Dunkerley & (Ragle & Schneider 1995). General anesthesia is Hanson 1997; Loesch & Rodgerson 2003; Embert- associated with its own inherent risks including son 2006). The most common causes of enlarged cardiac arrest, myopathy, neuropathy, and limb ovaries are granulosa cell tumors (GCTs), cysts fractures during recovery (Mee et al. 1998). (luteal, follicular), and ovarian hematomas During the last decade, laparoscopic techniques (Meagher et al. 1977). GCT results in a spectrum and instruments have improved, and standing of clinical signs because of alterations in normal laparoscopic ovariectomy is commonly used for hormonal production, including stallion-like the removal of normal and oversized ovaries. behavior, aggressiveness, nymphomania, and dis- However, there is still some concern on the removal ruption of the normal estrous cycle (anestrus, pro- of large, oversized ovaries (15 cm and more) in the longed estrus, continuous estrus) (McCue et al. standing mare. Dissection of the pedicle and con- 2006). trolling the hemorrhage is no longer the major Complications associated with the removal of problem since the introduction of electrosurgical both healthy and diseased ovaries by traditional instruments, but removing the large ovary from Advances in Equine Laparoscopy, First Edition. Edited by Claude A. Ragle. © 2012 by John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc. 189
190 Advances in Equine Laparoscopy the abdomen without creating a large flank inci- Anesthesia, positioning, and sion is now the major challenge. Large flank inci- surgical preparation sions increase the risk of hemorrhage from the abdominal wall and intestinal prolapse during Instruments surgery. They also increase surgical time for closure and increase the risk of complications – 1 × 10 mm, 32-cm rigid 0° or 30° angled lapa- during wound healing (seroma formation, wound roscope (long laparoscope is less practical) dehiscence, infection) that may lead to a dimin- – 3 × 10-mm-diameter, 20-cm-long trocar- ished cosmetic result. cannula unit (one for the laparoscope, two for Developing techniques that are not too time- the instruments) consuming and that do not require a large flank – Reducers from 10 to 5 mm incision for the removal of large ovaries is attrac- – Laparoscopic injection needle tive (De Bont et al. 2010). Motorized morcellators – Laparoscopic scissors (5 or 10 mm) have been used successfully in standing mares, – Largest size claw grasping forceps but they are expensive (Kummer et al. 2010). – Retrieval bag: Cheaper methods using retrieval bags, intra- * Strong and large sterile plastic bag (e.g., abdominal suction, and dissection have been sterile laparoscopic instrument bag or developed, negating the need for large flank inci- sterile plastic cover for X-ray cassette) sions or general anesthesia (De Bont et al. 2010). * Or commercial retrieval bag (largest diam- eter ±15 cm) – 30- to 40-cm-long and 5- to 10-mm-diameter Indications cannula with semisharp trocar and suction for fluid aspiration from ovary Horses with enlarged ovaries (GCT, cystic ovary, – LigaSureTM or other electrosurgical vessel- ovarian hematoma, teratoma) are candidates for sealing instruments laparoscopic ovariectomy. The size of the ovary is, in most cases, no longer a contraindication for standing laparoscopic Preoperative preparation surgery. The size of pathologically enlarged ovaries normally varies between 8 and 30 cm. The Preoperatively, the mare should have a physical flank incision does not normally exceed 10 cm examination and a hematologic and serum bio- when using retrieval bags and intra-abdominal chemical profile screening if needed. A rectal dissection. examination and rectal ultrasound examination should always be carried out before surgery to determine the size of the ovary, its location, and Contraindications the presence of adhesions between the ovary and the surrounding tissue. There are no contraindications for standing lapa- The ultrasound examination is also important to roscopic ovariectomy for the removal of enlarged define the composition of the enlarged ovary. The ovaries. surgeon has to know if the enlarged ovary con- However, one should be prepared to convert tains pockets of fluid, which can be drained pre- to general anesthesia and ventral midline operatively using suction, or if the ovary is solid, celiotomy when the enlarged ovary is adhered to multicystic, or fluid-filled (cyst, hematoma). Also, the mesenterium, small intestines, or other sur- the size and location of the spleen can be checked rounding structures. Minor adhesions can be rectally to reduce the chance of perforating the dealt with laparoscopically. In case of extensive spleen when introducing the first trocar through adhesions or adhesions requiring small intestinal the left paralumbar fossa. resection, dissection of the ovarian pedicle can be The mare is weighed and the appropriate flank performed standing before inducing general is clipped preoperatively. Feed is withheld for anesthesia. 12–36 hours before surgery, with free access to
Ovariectomy for the Removal of Large Pathologic Ovaries in Mares 191 water. Immediately before surgery, procaine peni- anesthesia. A laparoscopic instrument bag can be cillin G (22,000 U/kg, intramuscularly [IM]) and attached to the draping for easier storage of the phenylbutazone (4.4 mg/kg, intravenously [IV]) long laparoscopic instruments. are administered. Thirty minutes after aceproma- zine (0.01 mg/kg, IV) administration, detomidine hydrochloride (0.015 mg/kg, IV) is administered, Surgical procedure and morphine (0.1 mg/kg, IM or IV) is given for additional analgesia. The mare is restrained in a The scope portal is located between the 17th and holding stock with the head cross tied in a padded 18th ribs ±5 cm ventral to the ventral border of the halter. Make sure the horse does not rest its neck tuber coxae. The two instrument portals are on the front door. This can lead to tracheal obstruc- located in the paralumbar fossa (Figure 18.1). tion and collapse. Cotton wool can be placed in Alternatively, all three portals can be made in the the ears to prevent sudden distraction, and the tail paralumbar fossa. The first laparoscopic cannula is bandaged and tied to the door of the stocks with with obturator is introduced blindly without tape to prevent movement during surgery. Make insufflation of the abdomen. The two other lapa- sure the horizontal bars of the stock are low roscopic cannulas are positioned after CO2 insuf- enough to enable free movement of all instru- flation under direct visualization. ments. A urinary catheter to facilitate bladder The first portal is made at the dorsal margin of decompression is placed for the duration of the the internal abdominal oblique muscle (mid tuber surgery. coxae level) midway between the last rib and the An assistant or an anesthetist should remain at tuber coxae. After a 1.5-cm stab incision is made, the mare’s head during the procedure, and this a 10-mm-diameter, 20-cm-long trocar-cannula person can also assist in providing extra equip- unit with a conical blunt obturator (Optomed ment to the surgeon. Endoscopy, Courtaboeuf Cedex, France) is inserted Sedation is maintained with detomidine hydro- into the abdomen slightly angled to the opposite chloride continuous rate infusion (CRI, 0.1 µg/kg/ stifle until perforation of the peritoneum is min). The paralumbar fossa is clipped to within achieved. Aspiration of room air in the abdomen 15 cm of the dorsal midline dorsally to the level of can often be heard because of the negative pres- the flank fold ventrally and from the 13th/14th rib sure normally present within the abdomen. On cranially to 5 cm caudal of the caudal border of the trocar removal, a 10-mm, 32-cm rigid 0° or 30° tuber coxae. The region is aseptically prepared angled laparoscope is inserted through the cannula and 2% mepivacaine hydrochloride (10–20 mL) is to check for proper intra-abdominal placement infiltrated subcutaneously and intramuscularly at the intended trocar sites before draping. The laparoscopy tower is positioned behind the horse. A small step is sometimes needed in big horses to maintain a comfortable position of both arms during surgery. Elevation of the shoulders, abduction of the upper arms, and flexion of the elbows should be avoided as they cause fatigue and loss of concentration. An electrosurgical unit, a CO2 bottle, and suction are also placed behind the mare. Large disposable drapes should be used and they should cover the horse from the shoulder to the tail. The drape should also be long enough to cover the horizontal bars of the stock even when the horse is moving from left to right. The drapes can be secured to the skin with skin Figure 18.1 Laparoscopic closed portals after removal of a staples or towel clamps without using local 20-cm GCT 2.
192 Advances in Equine Laparoscopy before CO2 insufflation is started. The abdomen is caudal to proximal approach is strongly recom- then insufflated with CO2 (6–8 L/min) with an mended when not using bipolar or unipolar elec- intra-abdominal pressure cutoff level of 12 mmHg. trosurgical instruments to seal the blood vessels. The laparoscopic portal between the 17th and 18th It leaves the ovary attached to a smaller pedicle, ribs ±5 cm ventral to the ventral border of the tuber which makes ligation of the pedicle much easier. coxae is then made under direct visualization. A 5- to 8-metric vicryl suture is placed around the This avoids accidental injury or perforation of the pedicle and an extracorporeal 4S modified Roeder spleen. The laparoscope is then switched from the knot is tied and advanced using a knot pusher paralumbar position to the intercostal position, (Shettko et al. 2004). If the pedicle is too wide, a and the second instrument portal is made ±10 cm small vertical incision can be made in the middle ventral to the first one. A 20-cm laparoscopic of the pedicle. This opening is then used to guide trocar-cannula unit (Optomed Endoscopy) is one suture around the cranial half and one around introduced through the instrument portals. the caudal half of the pedicle. Both sutures are tied After observation of the ovarian pedicle, mepi- as described above using a slipknot. The advan- vacaine hydrochloride (2%, 15–20 mL) is adminis- tages of using a small opening in the mesovarium tered into the mesovarium and mesosalpinx and using a cranial and caudal ligature are easier through the dorsal instrument portal using a lapa- placement of the suture with less slipping away, roscopic injection needle (Optomed Endoscopy). less tissue per ligature, and better hemostasis. The The injection needle is removed and the ovary is mesovarium is then cut distal to the ligature, grasped using a 10-mm claw grasping forceps making sure the large ovary is firmly grasped with (Optomed Endoscopy) placed through the lower a 10-mm claw forceps. Any residual hemorrhage instrument portal. Some pathologic ovaries are so from the pedicle can be controlled with the Liga- large and heavy that lifting them and complete Sure or other electrosurgical equipment. Ligation exposure of the ovary are not possible. Appropri- with a small loop or laparoscopic vascular clips ate traction and some lifting will expose the proper can be used if one has no access to electrosurgical ligament of the ovary and the uterine horn. A instruments. 10-mm LigaSure vessel-sealing and cutting elec- The free ovary is now suspended in the abdo trosurgical instrument (Valley Lab, Boulder, CO) men by the grasping forceps. If an ovary is large is introduced through the dorsal instrument and heavy, elevating it clear of the intestines is portal. The LigaSure is placed across the cranial impossible and only the top of the ovary is aspect of the mesovarium ±1 cm proximal to the exposed. ovary, and the mesovarium, mesosalpinx, and Depending on ovary size, a number of tech- proper ligament are cauterized, incising in a niques can be used to facilitate safe removal cranial to caudal direction, taking care to avoid the through the smallest possible skin incision. uterus, until dissected completely free. LigaSure For smaller solid ovaries (≤10 cm), the dorsal or and some other electrosurgical instruments will ventral instrument portal can be extended ven- first seal and then cut the tissue. The 10-mm Liga- trally to create a 5-cm skin incision. The external Sure can only grasp relatively small tissue bites. abdominal oblique, internal abdominal oblique, This often requires separating the mesovarium in and transverse abdominal muscles are subse- two planes to ensure proper coagulation and quently bluntly divided parallel to their fiber cutting. Other electrosurgical instruments will alignment using a grid technique (Figure 18.2). It only seal the blood vessels and the cutting is per- is important that the opening in the peritoneum is formed using laparoscopic scissors. The latter is sufficiently large to allow easy passage of the more time-consuming and requires continuously ovary without dropping it in the abdomen. This interchanging both instruments. can be achieved with both index fingers or by Dissection can also be started in the caudal to using two blunt obturators in very large or fat cranial direction starting with dividing the proper mares. The ovary is positioned against the opening ligament, salpinx, and mesosalpinx. Gentle trac- and grasped externally using large grasping or tion is applied to the grasping forceps to optimize claw forceps. An assistant stretches the margins of visualization and access to those structures. This the incision, while the surgeon twists and lifts the
Ovariectomy for the Removal of Large Pathologic Ovaries in Mares 193 Figure 18.2 Enlarged 8-cm proximal flank portal grid technique. Figure 18.3 Intra-abdominal ovary suction. ovary using the large grasping or claw forceps and manipulates it through the small incision. For larger ovaries (15–30 cm), the incision can be extended in a vertical plane connecting both instrument portals, creating a skin incision of ±10 cm. A number of techniques can be used to reduce the size of larger ovaries before removal. Aspiration of fluid When intraovarian fluid is detected presurgically by ultrasonography, a cannula aspiration tech- nique can be used to reduce the size (Figure 18.3). Figure 18.4 Fluid removed from ovarium hematoma; only A 5- to 10-mm-diameter metal suction cannula the capsule remains. with blunt trocar (Richard Wolf GmbH, Knittlin- gen, Germany) can be inserted through one of the hematomas are more difficult to empty completely instrument portals. In some cases, the blunt trocar by suction. The cannula and suction tube are often can be pushed easily through the ovarian capsule; blocked with the very thick coagulated and in other cases, a small incision in the ovarian digested blood, but suction will often decrease the capsule is made using laparoscopic scissors to size to ±50% (Figure 18.5A–C). facilitate entrance of the suction cannula. The cannula is connected to a sterile suction tube and all fluid pockets are aspirated. This might require Bagging the ovary and several puncture sites. Aspiration of fluid can also intra-abdominal dissection be achieved at the start of the procedure before the dissection of the pedicle. In large cystic ovaries, For large solid mass ovaries that cannot be drained several liters of fluid can be removed, leaving only or ovaries that remain too big after fluid removal, an empty ovarian capsule intra-abdominally, intra-abdominal dissection within a strong which can easily be removed through a 3- to 5-cm retrieval bag is indicated. Commercial retrieval skin incision (Figure 18.4). Long-standing ovarian bags made of nylon can be used, providing the
194 Advances in Equine Laparoscopy (A) (B) (C) Figure 18.5 (A,B) Ovarian hematoma after removal and partial suction. (C) Ovarian hematoma removal after intra- abdominal suction. ovary is not larger than 15 cm (Super E-Sac, Espiner It is up to the surgeon’s preference which portal Medical Ltd, Bristol, UK). The nylon bag is intro- will be enlarged. Sterile disposable X-ray cassette duced in the abdomen before dissecting the covers can be used, but I use a strong plastic dis- pedicle. The oviduct, mesosalpinx, and proper posable instrument bag (one-section adhesive bag, ligament can be cut previously to reduce the size 43 × 38 cm; Foliodrape® No. 258 322, Hartmann, of the pedicle. The bag is introduced in the Heidenheim, Germany). abdomen through a 15-mm-diameter cannula and Hand-assisted bagging of the ovary after dis- opened by pulling the colored tabs using 5-mm secting the pedicle requires a surgeon with small grasping forceps. The ovary is bagged and the bag hands if the skin incision does not exceed 10 cm in is partially closed by pulling the wire drawstring. length. After sectioning the pedicle, the ovary is The pedicle is then cut as described above. The firmly grasped within the 10-mm claw grasping ovary is now ready for dissection. forceps. The skin at the proximal or distal instru- For ovaries that are larger than 15 cm, a strong ment portal is enlarged and the underlying sterile plastic bag can be introduced intra- muscles are split in the fiber direction. The bag and abdominally and the ovary manipulated into it, one hand are introduced in the abdomen, and the either by a hand-assisted intra-abdominal tech- plastic bag is positioned around the ovary. At that nique or by the use of grasping forceps. This moment, visualization is poor, partially due to loss requires enlarging one of the instrument portals. of pneumoperitoneum.
Ovariectomy for the Removal of Large Pathologic Ovaries in Mares 195 (A) (B) Figure 18.6 (A) Open polyprop bag. (B) Closed polyprop bag. Bagging the enlarged ovary by the use of grasp- site, completely isolating the ovary from the ing forceps requires a smaller enlargement of one abdomen. An assistant can then open the bag by of the portals. Often, a third instrument portal is pulling the edges of the bag apart, exposing a needed to open the plastic bag wide enough using small part of the enlarged ovary (Figure 18.8). grasping forceps to allow entrance of the ovary. Remaining fluid pockets can be drained by suction Non-hand-assisted bagging an enlarged ovary or by making stab incisions in the ovary (Figure through a 5- to 10-cm enlarged instrument portal 18.9). can be time-consuming, and the most difficult part Outward traction on the edges of the bag sepa- is keeping the bag open so the ovary can be rates the abdominal muscles, allowing for easy dropped into it. intra-abdominal dissection using a scalpel blade For this reason, I developed a “polypropylene or scissors. Rotating the ovary along a vertical band plastic retrieval bag.” A 160-cm-long, 1-cm- plane with a forceps and deeply incising each new wide, and 3-mm-thick polypropylene band is used piece of tissue allow it to be sectioned into smaller in a loop fashion, and the adhesive edges of the pieces without contamination or loss of segments bag (one-section adhesive bag, 43 × 38 cm; Folio- within the abdominal cavity. However, care should drape No. 258 322, Hartmann) are folded over the be taken not to incise the bag. Nylon bags are band so that it resembles a brailer bag (Figure stronger and rip free even after accidental stab- 18.6A,B). The distal or proximal instrument portal bing. The pieces of ovary can be removed from the is enlarged to 5–8 cm, and the polypropylene band bag with claw forceps or the bag containing the retrieval bag is introduced in the abdomen after smaller segments can then easily be manipulated splitting the muscles as described above. Once in through the 5- to 8-cm incision (Figure 18.10). the abdomen, the polypropylene band will open the edges of the bag and the enlarged ovary can be positioned in the bag (Figure 18.7A–E). Once Motorized morcellator the ovary is bagged, the polypropylene band is pulled outside the abdomen and the edges of the Motorized morcellators are expensive but can be bag are grasped with both hands (Figure 18.8). used to remove large ovaries through a small lapa- Bagging the ovary in this way is easier and less roscopic portal (Kummer et al. 2010). A morcella- time-consuming. Large ovaries of 20–30 cm can be tor consists of a stainless steel cylinder with a bagged through a relatively small (5–8 cm) flank cone-shaped knife at its intra-abdominal end. It is incision. placed inside the upper or lower cannula. A grasp- Once the enlarged ovary is bagged, the opening ing forceps is inserted through this cylinder with of the bag is then pulled back through the incision the knife, and the ovary is grasped and pushed
(A) (B) (C) (D) (E) Figure 18.7 (A) GCT entering a polyprop bag open in the abdomen. (B) Polyprop bag with GCT in situ. (C,D) Polyprop bag open in abdomen with ovary. (E) Bagging the ovary. 196
Ovariectomy for the Removal of Large Pathologic Ovaries in Mares 197 (A) (B) Figure 18.8 (A) GCT (25 cm) bagged and ready for intra-abdominal dissection. (B) Large GCT bagged and ready for intra-abdominal dissection. continuous pattern with 5 or 8 metric polyglactin 910 using a large 48 mm half-circle needle. The subcutaneous tissue is closed similarly with 3 metric polydioxanone or polyglecaprone 25, and the skin is stapled or sutured in an interrupted pattern using 3 metric polydioxanone (Figures 18.1 and 18.11). An adhesive dressing can be placed over the surgical sites to further prevent postoperative contamination. Postoperative care Mares are muzzled until free of sedative effects Figure 18.9 Suction GCT in bag before intra-abdominal and are then gradually reintroduced to normal dissection. feeding. Procaine penicillin G (22,000 U/kg, IM) and phenylbutazone (2.2 mg/kg orally once daily) against the rotating knife. Cylindrical tissue blocks are administered for 3–5 days. Horses can be dis- from 8 to 10 mm thick and up to 30 cm long can charged 48 hours after surgery. A rug can be placed be cut from the ovary and removed from the for 2 weeks to protect the surgical wounds. Skin abdomen using the grasping forceps. This pro staples/sutures are removed 14 days postopera- cedure is then repeated numerous times until the tively. After 2 weeks of complete stable rest, daily entire ovary is removed. The morcellator can also hand walking for 20–30 minutes accompanied by be used on a bagged ovary to prevent intra- turnout in a small paddock is allowed. Mares are abdominal contamination. gradually returned to work 4 weeks after surgery. Once the enlarged ovary is removed, all can- nulas are removed and the abdominal wall is closed. Complications The enlarged portal can be closed, either in a single layer incorporating all three muscle layers Complications following laparoscopic removal of or only the external abdominal oblique and inter- GCT or other types of oversized ovaries are nal abdominal oblique muscles, in a simple uncommon.