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Laparoscopy
Vet Clin Small Anim 33 (2003) 1147–1163
Laparoscopy Eric Monnet, DVM, PhD*, David C. Twedt, DVM Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
Laparoscopy is a minimally invasive technique for viewing the internal structures of the abdominal cavity. The procedure involves distention of the abdominal cavity with gas and then using a rigid telescope (laparoscope) placed through a portal positioned into the abdominal wall to examine the contents of the peritoneal cavity. Once the telescope is in place, either biopsy forceps or an assortment of surgical instruments can be introduced into the abdomen through adjacent portals to perform various diagnostic or surgical procedures. The minimal invasiveness of the procedure, rapid patient recovery, and diagnostic accuracy make laparoscopy an ideal technique compared with other more invasive procedures. Small animal laparoscopy has not only developed into a diagnostic tool but, more recently, has progressed to where it has become a means for minimally invasive surgical procedures. Laparoscopy is simple to perform and considered to be safe, having few complications. Despite the advent of newer laboratory tests, imaging techniques, and ultrasound-directed fine-needle biopsy or aspiration, laparoscopy remains a valuable tool when appropriately applied in a diagnostic plan. Laparoscopy may also provide accurate and definitive diagnostic and staging information that would otherwise only be obtained through a surgical laparotomy.
Indications and contraindications The most common indication for laparoscopy is to examine and biopsy the abdominal organs or masses. Laparoscopy is also a means of performing various surgical procedures. Laparoscopy may not completely replace abdominal exploratory surgery, but it can provide a minimally invasive
* Corresponding author. E-mail address: [email protected] (E. Monnet). 0195-5616/03/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/S0195-5616(03)00058-5
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means of accomplishing a number of diagnostic and surgical procedures in small animals (Box 1). Diagnostic laparoscopy is commonly used as a method for obtaining liver, pancreas, kidney, splenic, and intestinal biopsies. It is generally accepted that laparoscopy provides better liver biopsy tissues than other traditional percutaneous methods. Laparoscopy is also used in oncology to diagnose and stage the extent of malignancy, either primary or metastatic [1,2]. Laparoscopy may divulge small (0.5 cm or less) metastatic lesions, peritoneal metastases, or other organ involvement that is not easily observed by other diagnostic techniques. Full-thickness intestinal biopsies can be performed using laparoscopic assistance. Common surgical techniques currently being performed in small animals include cryptorchid surgery, ovariohysterectomy, and prophylactic gastropexy (Box 2). Other laparoscopic procedures performed are cystoscopy, jejunostomy or gastrostomy feeding tube placement, abdominal lavage tube placement, and even adrenalectomy. The potential for laparoscopic surgery in veterinary medicine seems to be limited only by our innovation and the surgical instrumentation available. The advantages of surgical laparoscopy compared with conventional open surgical exploratory laparotomy include improved patient recovery because of smaller surgical sites and lower postoperative morbidity with a lower infection rate and less postoperative pain [3,4]. There are few contraindications to laparoscopy because of the minimal invasiveness of the procedure. Ascites, abnormal clotting times, and poor patient condition are the only relative contraindications to laparoscopy. Generally, the ascitic fluid is removed before or during the procedure and has little influence over the probability of success of laparoscopy. Additionally, abnormal clotting times may not completely preclude the performance of laparoscopy. This is because abnormal coagulation from liver disease does not always seem to correlate with excessive bleeding at the biopsy site [5]. A further benefit of laparoscopy is that it is possible to select
Box 1. Basic diagnostic laparoscopic techniques Liver biopsy Cholecystocentesis Pancreatic biopsy Intestinal biopsy Adrenal evaluation Splenic evaluation Reproductive evaluation
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Box 2. Basic surgical laparoscopic techniques Feeding tube placement Gastropexy Ovariohysterectomy Cryptorchid surgery Gastric foreign body removal Cystoscopy
areas visually that are less vascular and to monitor the extent of bleeding after a biopsy. Absolute contraindications to laparoscopy include septic peritonitis or conditions where obvious conventional surgical intervention is indicated. Relative contraindications include patient condition, small body size (<2 kg of body weight), and obesity. Patients representing a poor anesthetic or surgical risk would obviously not be suitable candidates for the procedure. We have performed laparoscopy on severely debilitated patients, using only local anesthesia and sedation, in which general anesthesia and surgical laparotomy were considered to be too risky.
Laparoscopic equipment The basic equipment required for diagnostic laparoscopy includes the telescope, corresponding trocar-cannula units, light source, Veress (insufflation) needle gas insufflator, and various forceps and ancillary instruments (Box 3). The telescope most commonly employed by the authors is a 5-mm diameter 0 field of view telescope used for routine diagnostic laparoscopy [6]. The 0 designation means that the telescope views the visual field directly in front of the telescope. Angled viewing scopes, with the most common being a 30 telescope, view in a 30 downward direction. The angled telescopes enable the operator to look over the top of organs and examine small areas. The telescope must be attached to a light source using a light guide cable. A xenon light source with a high intensity is considered to give the truest colors of the abdominal organs and is recommended [6]. Video-assisted endoscopy is now considered to be the norm in performing laparoscopy. When an endoscopic videocamera is attached to the telescope, it allows the image to be viewed on a monitor. A Veress needle is used for initial gas insufflation of the abdominal cavity. The needle consists of an outer sharp cutting tip, but contained within the needle is a spring-loaded obturator that retracts into the needle shaft as it traverses the abdominal wall and then advances beyond the sharp tip after
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Box 3. Basic laparoscopic equipment 5-mm telescope (0 ) Two cannulae Veress needle Light source Light cable Carbon dioxide insufflator Palpation probe Oval biopsy forceps Punch biopsy forceps Grasping forceps Scissors Videocamera and monitor Optional: photographic documentation
the needle penetrates the abdominal wall. With the internal obturator in place, needle injury to internal abdominal organs is prevented. The hub of the needle is then attached to insufflation tubing that has been attached to the automatic gas insufflator. Most automatic insufflators are similar in function and deliver gas at a prescribed rate while maintaining a predetermined intra-abdominal pressure. Carbon dioxide is considered to be the gas of choice for insufflation because of safety in preventing air emboli and spark ignition during cauterization [6]. After insufflation of the abdominal cavity, the telescope and instruments can be placed through the abdominal cavity by a trocar-cannula unit that is of a corresponding size to receive either the telescope or instruments. The trocar is a sharp-pointed instrument; when it is placed into the cannula, it becomes possible to penetrate abdominal muscles and peritoneum. Once the trocar is removed, the cannula remains in place traversing the abdominal wall and creates a portal for the introduction of the telescope or instruments into the abdominal cavity. Most cannulae contain an internal one-way valve that prevents loss of insufflated gas once the trocar is removed after abdominal entry. Most cannulae also contain a Luer-lock adapter valve for attachment of the carbon dioxide line to ensure continued gas insufflation through the cannula. During diagnostic laparoscopy, a number of accessory instruments are essential. These are instruments that must be placed through a second cannula unit. A palpation probe is required to move and palpate the abdominal organs. Most palpation probes have centimeter markings so that one can estimate the relative size of organs or lesions. The palpation probe can also be used to apply pressure over an excessively bleeding biopsy site. Oval biopsy cup forceps are the most versatile forceps and are commonly
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used for biopsy of the liver, spleen, abdominal masses, and lymph nodes. Punch type biopsy forceps are sometimes preferred for pancreatic biopsies. A ‘‘true-cut’’ type biopsy needle is needed for kidney or deep tissue biopsies. Surgical laparoscopy often requires a vast array of instruments designed for specific indications. Common instruments include grasping forceps, scissors, aspiration tubes, and clip applicators. Certain specialized instruments, such as stapling devices, are generally 10 mm or larger in diameter. Many of the biopsy and surgical instruments also have a capability for monopolar electrosurgery at their distal tip.
Basic laparoscopic technique Preparation, restraint, and surgical considerations Once the decision is made to perform a laparoscopy, there are a number of presurgical details and considerations to be made. The patient should be fasted for at least 12 hours before the procedure, and the urinary bladder should be evacuated to prevent puncture with trocars or cannulae. Laparoscopy is commonly performed using general gas anesthesia. Most patients tolerate general anesthesia well during laparoscopy; however, it is expected that the pneumoperitoneum from carbon dioxide insufflation will increase intra-abdominal pressure and may interfere with excursions of the diaphragm [7,8]. In some situations, the authors perform diagnostic laparoscopy using only heavy sedation in conjunction with local anesthesia at the entry sites. It is advisable to avoid high intra-abdominal insufflation pressures or excessive tilting of the surgical table, which would apply undue pressure from the abdominal organs on the diaphragm. In cases in which ventilation becomes compromised, assisted ventilation is necessary. The objectives of the laparoscopy procedure must be determined to select the appropriate cannula portal placement sites. The two most common approaches are the right lateral approach and midline approach. The right lateral approach is the recommended approach for diagnostic evaluation of the liver, gallbladder, right limb of the pancreas, duodenum, right kidney, and right adrenal gland. A ventral approach is often useful for many operative procedures and offers good visualization of the liver, gallbladder, pancreas, stomach, intestines, reproductive system, urinary bladder, and spleen. In the ventral approach, the primary portal is placed on or adjacent to the midline near the umbilicus. A disadvantage of the ventral approach is that the falciform ligament may hinder visualization of the anterior abdomen, especially in obese animals. A left lateral approach may be used, but the spleen lies directly under the normal entry sites, and there is the potential for splenic trauma by a trocar. With any approach, the entry site may be modified by moving either cranial or caudal to give adequate working space for the laparoscope as well as for the procedure to be performed.
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Technique The first step in laparoscopy is to establish a pneumoperitoneum before cannula placement. This begins with placement of the Veress needle either adjacent to the cannula portal sites or in the same site to be used by the first telescope portal. Once the needle passes through the abdominal wall, one should make sure that the Veress needle is actually in the abdominal cavity and is not retained in the muscle planes of the abdominal wall or penetrating an abdominal organ. Inadvertent insufflation in the subcutaneous tissues with carbon dioxide makes the procedure almost impossible to continue. To ensure that the Veress needle is in the abdominal cavity and not within an organ, the ‘‘hanging drop test’’ can be performed. This requires placing a drop of saline in the hub of the Veress needle and then lifting the abdominal wall with the needle shaft. The negative pressure within the abdominal cavity pulls the drop of saline into the needle. This finding confirms that the needle is in the peritoneal cavity. Insufflation of gas into a mass, organ, or vessel can result in fatal air emboli [9]. The Veress needle is then attached to the automatic insufflator. When the abdomen is adequately distended with carbon dioxide, it becomes tympanic on palpation. The abdominal pressure should be no greater than 15 mm Hg, and in most cases, 10 mm Hg is adequate to maintain abdominal distention and perform laparoscopy in small animals. A cannula unit that receives the telescope is then placed through the abdominal wall [10]. The entry site is determined, and an incision is made through the skin large enough to accommodate the cannula. The trocarcannula unit is then passed through the abdominal wall using a twisting and thrusting motion. One can hear a hollow ‘‘pop’’ and the sound of hissing air through the trocar once it has entered the gas-distended abdomen. Immediately after abdominal entry, the sharp trocar is removed from the cannula to prevent possible organ trauma. After initial cannula placement, the telescope is prepared for entry into the abdomen. The light cable is then attached to the telescope, and the light guide cable is attached to the light source. A videocamera is next attached to the telescope and focused to give a sharp clear image. The telescope is now advanced through the cannula and into the abdomen. Frequently, the image becomes blurred as the telescope enters the abdominal cavity as a result of tissue, fluid, or blood contaminating the lens as the telescope is passed through the cannula or from condensation on the lens as a result of temperature change. When this occurs, the tip of the scope is simply cleaned by carefully wiping the tip against abdominal tissues, such as the intestine. If the image is still blurred, the telescope is removed and cleaned using saline-soaked gauze. Once the telescope is in the abdominal cavity, careful examination of the contents is performed. Next, the site of entry for the second (accessory) portal is selected. This location depends on the ancillary procedures that are
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to be performed. The technique for placement of the accessory cannula involves visual laparoscopic control, viewing the trocar entry from inside the abdomen. Once the approximate entry site is determined, the abdominal wall is depressed with a finger and the site is viewed internally, identifying the palpation site. The entry site is then assessed to ensure that underlying organs will not be traumatized during trocar entry. The second cannula is then placed through the abdominal wall as described in the procedure for placement of the first telescope cannula, except this time, one watches the trocar entry viewed internally. Once the cannula has entered the abdomen, the trocar is removed. Exploration of the abdominal cavity is assisted by using the palpation probe to ‘‘feel’’ and move the organs as needed. When the probe or any instrument is passed into the abdomen, it should be viewed as it exits the cannula, and it is then directed to the area of examination. Instruments should never be blindly passed into the abdomen but rather viewed internally as they pass through the cannula and directed to the area of interest. Using this technique prevents serious tissue trauma by the probe or other accessory instruments. At the conclusion of the laparoscopic procedure, the instruments and telescope are removed and the pneumoperitoneum is allowed to escape. The cannulae are then removed, and the puncture sites are sutured in a routine manner, concluding the laparoscopic procedure. For postoperative pain management, we generally infiltrate bupivacaine local anesthesia in the trocar-cannula sites and prescribe systemic analgesia.
Basic laparoscopic biopsy techniques Liver biopsy Laparoscopic liver biopsy is considered by many to be the preferred method of obtaining a liver biopsy [10,11]. Other diagnostic modalities often do not provide sufficient information on the liver. One is able to view not only the liver but adjacent organs as well. A right lateral approach for evaluation of the liver, extrahepatic biliary system, and right limb of the pancreas is recommended. Using this approach, one is able to examine greater than 85% of the liver surface, take directed tissue biopsies, and monitor for excessive bleeding. We recommend using 5-mm oval cup biopsy forceps for the liver [12]. A recent study emphasized the benefit of laparoscopic cup biopsies when two 18-gauge needle biopsies were compared with the laparoscopic cup biopsies [13]. Before liver biopsy, the coagulation parameters are generally evaluated, including bleeding time. Although coagulopathies are a relative contraindication to liver biopsy, the coagulation status does not necessarily predict whether the patient will bleed from a liver biopsy.
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Fig. 1. Biopsy of the liver with cup biopsy forceps.
The biopsy forceps are directed to the area of the liver to be sampled. Either an edge of the liver or the surface of the liver can be biopsied with forceps (Fig. 1). It is always important to biopsy three to four areas of the liver, including areas that appear normal as well as those that appear abnormal. We generally hold the cups tightly closed for approximately 15 to 30 seconds before pulling the sample away from the liver. Some have suggested that biopsies taken at the edge of the liver may not reflect pathologic findings of deeper samples, because the subcapsular tissues are more reactive and fibrotic. The biopsy area is then closely monitored for excessive bleeding. Generally, most biopsy sites do not bleed much. If bleeding is considered to be excessive, several steps should be taken. The palpation probe can be placed into the biopsy site, with pressure applied over the area with the tip of the probe. Alternatively, a small piece of saline-soaked Gel-Foam (Pharmacia and Upjohn Company, Kalamazoo, MI) can be placed into the biopsy site using either laparoscopic grasping or biopsy forceps. These options are sufficient to control excessive bleeding. Pancreatic biopsy Laparoscopic forceps can also be used to biopsy the pancreas. We generally find pancreatic biopsies to be free of complications, and a study evaluating laparoscopic pancreatic biopsies in normal dogs found no postoperative complications or indications of secondary pancreatitis [12,14]. We believe that the punch type biopsy forceps work well for pancreatic biopsies; however, the cup biopsy forceps can also be used (Fig. 2). To obtain a pancreatic biopsy, the right lateral approach is preferred. This approach gives an excellent view of the duodenum and right limb of the pancreas as well as the extrahepatic biliary system and liver. The left limb of the pancreas is more difficult to examine from the right lateral approach,
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Fig. 2. Pancreatic biopsy taken from a normal pancreas using punch type biopsy forceps.
however. The biopsy site selected should be at the edge of the pancreas and away from the pancreatic ducts that traverse the center of the gland and subsequently enter the duodenum with the common bile duct. We generally take only one or two representative biopsy sample of the pancreas unless multiple lesions are present. Renal biopsy Laparoscopy is well suited for the evaluation and biopsy of the kidney [15,16]. To biopsy the kidney, we use an automatic ‘‘core type’’ biopsy needle (Vet-Core Biopsy Needle [16-gauge diameter]; Cook Veterinary Products, Bloomington, IN). The advantage is direct visualization of the kidney, which allows the operator to navigate the biopsy needle to the desired site to be sampled as well as to monitor for excessive postoperative bleeding. Before a kidney biopsy, adequate renal evaluation is necessary, including such considerations as renal excretory function, ultrasonography, or intravenous urography. This is important to determine which kidney to sample. Unless there is a specific indication to biopsy the left kidney the right kidney is preferred because it is less movable. A left kidney biopsy through a left lateral approach is more difficult because of the location of the spleen underlying the usual cannula entry site. Using a right lateral midabdominal telescope placement, the right kidney is easily visualized (Fig. 3). The authors then always place a second cannula so that a palpation probe is available to provide tamponade at the biopsy site. The palpation probe is placed in the abdomen near the kidney. Once the area of the kidney to biopsy is determined, a biopsy needle is directed to the
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Fig. 3. A view showing the right kidney from a right lateral approach. Also seen are the vena cava, portal vein, and caudate lobe of the liver. The right kidney is less movable and easier to biopsy.
site. This involves external palpation of the right midparalumbar region caudal to the last rib so as to select the location for the needle to transverse the abdominal wall. While viewing with the telescope internally, one palpates the abdominal wall with a finger for selection of an appropriate entry site. Next, a 2-mm skin incision is made at the desired entry site, and the needle is directed into the abdominal cavity and to the kidney. The usual location of sample collection is from the cranial or caudal pole of the kidney, being careful to obtain predominantly cortex with little medulla. The biopsy needle is seated through the renal capsule, and the needle is fired. The biopsy needle is then removed from the abdominal cavity. There are generally several milliliters of blood flowing from the biopsy site, and the palpation probe is quickly moved over the bleeding area, with pressure is applied for several minutes. Additional samples are taken if the first sample is not considered to be suitable. There are several precautions to keep in mind when obtaining a renal biopsy. First, the patient should not have been given drugs to increase renal blood flow (ie, dopamine), and the needle entry site through the abdominal wall should be caudal to the diaphragm. If the needle penetrates the diaphragm, an iatrogenically induced pneumothorax may result from leakage of the pneumoperitoneum into the thorax. Finally, one should avoid directing the needle deep into the kidney and involving the corticomedullary junction of the kidney, where the large arcuate vessels are located.
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Intestinal biopsy Small intestinal biopsies can be obtained with the laparoscope using the technique of grasping and then exteriorizing that portion of intestine through the abdominal wall. The intestinal biopsy sample is then obtained from the exteriorized bowel as would be done with a standard surgical biopsy [17]. The technique involves using 5-mm atraumatic grasping forceps with multiple teeth to grasp the intestine at the site to be sampled. It is often necessary to ‘‘run’’ the bowel using two grasping forceps to select a location to biopsy. Once the location is determined, the antimesenteric border of the intestine is firmly grasped with the forceps and the intestine is pulled to the cannula. A scalpel blade is then used to increase the cannula incision sufficiently so as to exteriorize the loop of bowel. One can watch the scalpel blade internally enter parallel to the cannula shaft and then cut away from the cannula to increase the incision length. Once the cannula incision is extended, a 3- to 4-cm loop of intestine is exteriorized and stay sutures are used in the intestine to prevent it from falling back into the abdominal cavity (Fig. 4). A small full-thickness biopsy is obtained in the same manner as one would use when performing an open abdominal surgical biopsy. The intestine is then returned to the abdominal cavity.
Fig. 4. After identification of the loop of bowel to biopsy, 5-mm atraumatic grasping forceps with multiple teeth are used to grasp the jejunum. The loop is exteriorized through the abdominal wall at one of the cannula sites. A stay suture is placed in the loop as soon as it is exteriorized.
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The intestinal biopsy should be the last laparoscopic procedure to be performed, because the pneumoperitoneum is lost during the procedure. If additional intestinal biopsies or other laparoscopic procedures are to be performed, the trocar-cannula must be reintroduced through the abdominal incision and the pneumoperitoneum re-established. A technique for multiple biopsies of the intestine using a serosal patch graph has also been described [17]. This technique involves retaining each segment of bowel biopsied using stay sutures after exteriorization and biopsy. The different biopsy sites are then sutured together to create a serosal patch graft. Other biopsy techniques A number of other biopsy techniques can also be performed with laparoscopic direction. These include biopsy of mass lesions, lymph nodes, the spleen, and the adrenal gland. Splenic biopsies are generally safe to perform using the cup type biopsy forceps or a biopsy needle. The technique, precautions, and coagulation control methods are the same as those described for a liver biopsy. Adrenal biopsies are sometimes performed when an adrenal mass is identified. Care should be taken, because bleeding after adrenal biopsy is common and hemostatic precautions are usually necessary. Cup forceps are used to obtain adrenal biopsies. Laparoscopy may also be used to determine the cause of unexplained abdominal effusion. The fluid is aspirated under endoscopic direction to enable examination of the abdominal contents. Surgical laparoscopy There are a number of minimally invasive surgical procedures that the authors currently perform using laparoscopy. A complete description of these surgical techniques is beyond the scope of this article, and the reader is advised to refer to other publications covering surgical techniques. Most of these surgical procedures require multiple trocar-cannula portals, specific laparoscopic surgical instruments, loop ligatures, clip applicators or monopolar electrosurgery. The techniques described are the primary procedures to be used for laparoscopic surgery in veterinary medicine. Feeding tube placement Duodenostomy or jejunostomy feeding tubes can be placed using the laparoscope simply by exteriorizing a piece of intestine through the abdominal wall and inserting the tube externally [17]. The technique of bowel exteriorization is similar to that described for intestinal biopsy. The intestine must be pexied to the abdominal wall in conjunction with the tube placement. A gastrostomy feeding tube can also be placed using the laparoscopy by simply by exteriorizing the body of the stomach through the left abdominal wall and then inserting the tube externally after a gastropexy.
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Gastropexy A preventive gastropexy is used for high-risk gastric dilation-volvulus in animals. Laparoscopic gastropexy is performed by exteriorizing the pyloric antrum region of the stomach through the right abdominal wall [18,19]. The animal is placed in dorsal recumbency, and the telescope portal is placed on the midline at the level of the umbilicus. The instrument portal for the grasping forceps is placed 2 cm behind the last rib on the right side and at the junction of distal and proximal third of the last rib. A portion of the gastric antrum is exteriorized, and an incisional gastropexy is performed to develop the serosomuscularis flap that is then pexied to the transverse abdominal muscle. Ovariohysterectomy Ovariohysterectomy can be performed using laparoscopy in most medium- and large-sized dogs [20]. Limitations of laparoscopic-assisted ovariohysterectomy relate to the size of the patient, because the space in the abdominal cavity of small animals makes the procedure technically difficult. The advantage of laparoscopic ovariohysterectomy is the perceived rapid patient recovery after the procedure. Ovariohysterectomy is performed with the animal positioned in dorsal recumbency. Both ovarian pedicles are dissected and ligated. The ovarian pedicle can be ligated with either a suture or vascular clips (Fig. 5) [21]. Next, a pretied loop of suture (Endoloop Suture or Loop Ligature, Endoloop PDS II, Ethicon Inc, Somerville, NJ) is placed in the abdominal cavity through one cannula. The ovaries and uterine horns are then passed through the loop. The loop is tightened down at the level of the cervix (Fig. 6). The uterus is transected, and both the uterus and ovaries are removed through one of the cannula holes that has been enlarged. Cryptorchid surgery A testicle that is located in the abdominal cavity can be removed easily using laparoscopy [22]. Laparoscopic vasectomy can also be performed by means of this technique [23]. The dog is placed in dorsal recumbency, and the table is tilted with the dog’s head in the lower position. Gravity then displaces the abdominal organs in the cranial abdomen, which facilitates visualization of the internal inguinal canal. Internal inguinal rings are inspected to determine the presence of the vas deference and testicular arteries. If these structures are present, either the dog has already been castrated or the testicles are in the inguinal area. Absence of the vas deferens and testicular artery in the inguinal canal means the testicle is ectopic. The ectopic testicle is usually readily visible on entering the abdominal cavity. The vascular pedicle and the vas deference are ligated with a pretied suture or clips (Fig. 7). The ectopic testicle is transected and removed through one of the cannula holes.
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Fig. 5. (A) Ovarian pedicle exposed with caudal traction of the uterus. (B) Vascular clips have been placed on the ovarian pedicle.
Other potential surgical procedures Adrenalectomy, removal of remnants of ovarian pedicles, correction of hiatal hernias, and nephrectomy are other surgical procedures possible to perform using laparoscopy. Laparoscopic removal of pancreatic neoplasia,
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Fig. 6. Both uterine horns have been placed through an Endoloop. The Endoloop is tightened around the cervix. The suture is then cut, and the uterus is excised. The uterus and the ovaries are removed through one of the cannula holes that has been extended.
such as an insulinoma, is possible. Small animal surgical laparoscopy is limited only by one’s imagination and innovation as well as by the instrumentation available to accomplish the procedure [24,25]. Complications of laparoscopy The complication rate of laparoscopy is low. In a review of 360 consecutive cases involving diagnostic laparoscopy, the authors found
Fig. 7. Right cryptorchid testicle cranial to the bladder. An Endoloop has been placed around the pampiniform plexus.
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Box 4. Potential laparoscopic complications Anesthesia-related problems Veress needle/trocar insertion Vascular injury to abdominal wall Penetration of organs Perforation of hollow viscus Insufflation Subcutaneous emphysema Peritoneal tenting Inappropriate insufflation Pneumothorax Gas embolism Operative complications Bleeding Tissue injury Technical problems Lack of experience Equipment-related problems
a complication rate less than 2%. Potential complications are listed in Box 4. Serious complications include anesthetic- or cardiovascular-related death, bleeding, or air embolism [26].
Summary Laparoscopy is a minimally invasive technique for both diagnostic biopsy and surgical procedures. After the basic technique of laparoscopy is mastered and the appropriate indications are learned, these procedures become an easy and rewarding addition to any small animal veterinary practice.
References [1] Johnson GF, Twedt DC. Endoscopy and laparoscopy in the diagnosis and management of neoplasia in small animals. Vet Clin North Am Small Anim Pract 1977;7:77–92. [2] Wildt DE. Laparoscopy in the dog and cat. In: Harrison RM, Wildt DE, editors. Animal laparoscopy. Baltimore: Williams & Wilkins; 1980. p. 31–72. [3] Rothuizen J. Laparoscopy in small animal medicine. Vet Q 1985;3:225–8. [4] Bessler M, Whelan RL, Halverson A, et al. Is immune function better preserved after laparoscopic versus open colon resection? Surg Endosc 1994;8:881–3. [5] Richter KP. Laparoscopy in dogs and cats. Vet Clin North Am Small Anim Pract 2001; 4:707–27.
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[6] Magne ML, Tams TR. Laparoscopy: instrumentation and technique. In: Tams TR, editor. Small animal endoscopy. 2nd edition. St. Louis: CV Mosby; 1999. p. 397–408. [7] Bufalari A, Short CE, Giannoni C, Pedrick TP, Hardie RJ, Flanders JA. Evaluation of selected cardiopulmonary and cerebral responses during medetomidine, propofol, and halothane anesthesia for laparoscopy in dogs. Am J Vet Res 1997;12:1443–50. [8] Duke T, Steinacher SL, Remedios AM. Cardiopulmonary effects of using carbon dioxide for laparoscopic surgery in dogs. Vet Surg 1996;1:77–82. [9] Gilroy BA, Anson LW. Fatal air embolism during anesthesia for laparoscopy in a dog. J Am Vet Med Assoc 1987;5:552–4. [10] Kolata RJ, Freeman LJ. Access, portal placement and basic endosurgical skills. In: Freeman LJ, editor. Veterinary endosurgery. St. Louis: CV Mosby; 1999. p. 44–60. [11] Twedt DC, Johnson GF. Laparoscopy in the evaluation of liver disease in small animals. Am J Dig Dis 1977;22:571–80. [12] Twedt DC. Laparoscopy of the liver and pancreas. In: Tams TR, editor. Small animal endoscopy. 2nd edition. St. Louis: CV Mosby; 1999. p. 44–60. [13] Cole TC, Center SA, Flood SN, et al. Diagnostic comparison of needle and wedge biopsy specimens of the liver in dogs and cats. J Am Anim Hosp Assoc 2002;220(10):1483–90. [14] Harmoinen J, Saari S, Rinkinen M, Westermarck E. Evaluation of pancreatic forceps biopsy by laparoscopy in healthy beagles. Vet Ther 2002;3(1):31–6. [15] Grauer GF, Twedt DC, Morrow KN. Evaluation of laparoscopy for obtaining renal biopsy specimens from dogs and cats. J Am Vet Med Assoc 1983;183:677–9. [16] Grauer G. Laparoscopy of the urinary tract. In: Tams TR, editor. Small animal endoscopy. 2nd edition. St. Louis: CV Mosby; 1999. p. 427–30. [17] Rawlings CA, Howerth EW, Bement S, Canalis C. Laparoscopic-assisted enterostomy tube placement and full-thickness biopsy of the jejunum with serosal patching in dogs. Am J Vet Res 2002;63(9):1313–9. [18] Rawlings CA. Laparoscopic-assisted gastropexy. J Am Anim Hosp Assoc 2002;38(1):15–9. [19] Rawlings CA, Foutz TL, Mahaffey MB, Howerth EW, Bement S, Canalis C. A rapid and strong laparoscopic-assisted gastropexy in dogs. Am J Vet Res 2001;6:871–5. [20] Minami S, Okamoto Y, Eguchi H, Kato K. Successful laparoscopy assisted ovariohysterectomy in two dogs with pyometra. J Vet Med Sci 1997;9:845–7. [21] Stoloff DR. Laparoscopic suturing and knot tying techniques. In: Freeman LJ, editor. Veterinary endosurgery. St. Louis: CV Mosby; 1999. p. 73–91. [22] Pena FJ, Anel L, Dominguez JC, et al. Laparoscopic surgery in a clinical case of seminoma in a cryptorchid dog. Vet Rec 1998;142(24):671–2. [23] Silva LD, Onclin K, Donnay I, Verstegen JP. Laparoscopic vasectomy in the male dog. J Reprod Fertil Suppl 1993;47:399–401. [24] Rawlings CA, Howerth EW, Mahaffey MB, Foutz TL, et al. Laparoscopic-assisted cystopexy in dogs. Am J Vet Res 2002;63(9):1226–31. [25] Schulsinger DA, Sosa RE, Perlmutter AA, Vaughan ED, Jr. Acute and chronic interstitial cryotherapy of the adrenal gland as a treatment modality. J Endourol 1999;4:299–303. [26] Freeman LJ. Complications. In: Freeman LJ, editor. Veterinary endosurgery. St. Louis: CV Mosby; 1999. p. 93–101.
Laparoscopy Eric Monnet, DVM, PhD*, David C. Twedt, DVM Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
Laparoscopy is a minimally invasive technique for viewing the internal structures of the abdominal cavity. The procedure involves distention of the abdominal cavity with gas and then using a rigid telescope (laparoscope) placed through a portal positioned into the abdominal wall to examine the contents of the peritoneal cavity. Once the telescope is in place, either biopsy forceps or an assortment of surgical instruments can be introduced into the abdomen through adjacent portals to perform various diagnostic or surgical procedures. The minimal invasiveness of the procedure, rapid patient recovery, and diagnostic accuracy make laparoscopy an ideal technique compared with other more invasive procedures. Small animal laparoscopy has not only developed into a diagnostic tool but, more recently, has progressed to where it has become a means for minimally invasive surgical procedures. Laparoscopy is simple to perform and considered to be safe, having few complications. Despite the advent of newer laboratory tests, imaging techniques, and ultrasound-directed fine-needle biopsy or aspiration, laparoscopy remains a valuable tool when appropriately applied in a diagnostic plan. Laparoscopy may also provide accurate and definitive diagnostic and staging information that would otherwise only be obtained through a surgical laparotomy.
Indications and contraindications The most common indication for laparoscopy is to examine and biopsy the abdominal organs or masses. Laparoscopy is also a means of performing various surgical procedures. Laparoscopy may not completely replace abdominal exploratory surgery, but it can provide a minimally invasive
* Corresponding author. E-mail address: [email protected] (E. Monnet). 0195-5616/03/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/S0195-5616(03)00058-5
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means of accomplishing a number of diagnostic and surgical procedures in small animals (Box 1). Diagnostic laparoscopy is commonly used as a method for obtaining liver, pancreas, kidney, splenic, and intestinal biopsies. It is generally accepted that laparoscopy provides better liver biopsy tissues than other traditional percutaneous methods. Laparoscopy is also used in oncology to diagnose and stage the extent of malignancy, either primary or metastatic [1,2]. Laparoscopy may divulge small (0.5 cm or less) metastatic lesions, peritoneal metastases, or other organ involvement that is not easily observed by other diagnostic techniques. Full-thickness intestinal biopsies can be performed using laparoscopic assistance. Common surgical techniques currently being performed in small animals include cryptorchid surgery, ovariohysterectomy, and prophylactic gastropexy (Box 2). Other laparoscopic procedures performed are cystoscopy, jejunostomy or gastrostomy feeding tube placement, abdominal lavage tube placement, and even adrenalectomy. The potential for laparoscopic surgery in veterinary medicine seems to be limited only by our innovation and the surgical instrumentation available. The advantages of surgical laparoscopy compared with conventional open surgical exploratory laparotomy include improved patient recovery because of smaller surgical sites and lower postoperative morbidity with a lower infection rate and less postoperative pain [3,4]. There are few contraindications to laparoscopy because of the minimal invasiveness of the procedure. Ascites, abnormal clotting times, and poor patient condition are the only relative contraindications to laparoscopy. Generally, the ascitic fluid is removed before or during the procedure and has little influence over the probability of success of laparoscopy. Additionally, abnormal clotting times may not completely preclude the performance of laparoscopy. This is because abnormal coagulation from liver disease does not always seem to correlate with excessive bleeding at the biopsy site [5]. A further benefit of laparoscopy is that it is possible to select
Box 1. Basic diagnostic laparoscopic techniques Liver biopsy Cholecystocentesis Pancreatic biopsy Intestinal biopsy Adrenal evaluation Splenic evaluation Reproductive evaluation
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Box 2. Basic surgical laparoscopic techniques Feeding tube placement Gastropexy Ovariohysterectomy Cryptorchid surgery Gastric foreign body removal Cystoscopy
areas visually that are less vascular and to monitor the extent of bleeding after a biopsy. Absolute contraindications to laparoscopy include septic peritonitis or conditions where obvious conventional surgical intervention is indicated. Relative contraindications include patient condition, small body size (<2 kg of body weight), and obesity. Patients representing a poor anesthetic or surgical risk would obviously not be suitable candidates for the procedure. We have performed laparoscopy on severely debilitated patients, using only local anesthesia and sedation, in which general anesthesia and surgical laparotomy were considered to be too risky.
Laparoscopic equipment The basic equipment required for diagnostic laparoscopy includes the telescope, corresponding trocar-cannula units, light source, Veress (insufflation) needle gas insufflator, and various forceps and ancillary instruments (Box 3). The telescope most commonly employed by the authors is a 5-mm diameter 0 field of view telescope used for routine diagnostic laparoscopy [6]. The 0 designation means that the telescope views the visual field directly in front of the telescope. Angled viewing scopes, with the most common being a 30 telescope, view in a 30 downward direction. The angled telescopes enable the operator to look over the top of organs and examine small areas. The telescope must be attached to a light source using a light guide cable. A xenon light source with a high intensity is considered to give the truest colors of the abdominal organs and is recommended [6]. Video-assisted endoscopy is now considered to be the norm in performing laparoscopy. When an endoscopic videocamera is attached to the telescope, it allows the image to be viewed on a monitor. A Veress needle is used for initial gas insufflation of the abdominal cavity. The needle consists of an outer sharp cutting tip, but contained within the needle is a spring-loaded obturator that retracts into the needle shaft as it traverses the abdominal wall and then advances beyond the sharp tip after
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Box 3. Basic laparoscopic equipment 5-mm telescope (0 ) Two cannulae Veress needle Light source Light cable Carbon dioxide insufflator Palpation probe Oval biopsy forceps Punch biopsy forceps Grasping forceps Scissors Videocamera and monitor Optional: photographic documentation
the needle penetrates the abdominal wall. With the internal obturator in place, needle injury to internal abdominal organs is prevented. The hub of the needle is then attached to insufflation tubing that has been attached to the automatic gas insufflator. Most automatic insufflators are similar in function and deliver gas at a prescribed rate while maintaining a predetermined intra-abdominal pressure. Carbon dioxide is considered to be the gas of choice for insufflation because of safety in preventing air emboli and spark ignition during cauterization [6]. After insufflation of the abdominal cavity, the telescope and instruments can be placed through the abdominal cavity by a trocar-cannula unit that is of a corresponding size to receive either the telescope or instruments. The trocar is a sharp-pointed instrument; when it is placed into the cannula, it becomes possible to penetrate abdominal muscles and peritoneum. Once the trocar is removed, the cannula remains in place traversing the abdominal wall and creates a portal for the introduction of the telescope or instruments into the abdominal cavity. Most cannulae contain an internal one-way valve that prevents loss of insufflated gas once the trocar is removed after abdominal entry. Most cannulae also contain a Luer-lock adapter valve for attachment of the carbon dioxide line to ensure continued gas insufflation through the cannula. During diagnostic laparoscopy, a number of accessory instruments are essential. These are instruments that must be placed through a second cannula unit. A palpation probe is required to move and palpate the abdominal organs. Most palpation probes have centimeter markings so that one can estimate the relative size of organs or lesions. The palpation probe can also be used to apply pressure over an excessively bleeding biopsy site. Oval biopsy cup forceps are the most versatile forceps and are commonly
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used for biopsy of the liver, spleen, abdominal masses, and lymph nodes. Punch type biopsy forceps are sometimes preferred for pancreatic biopsies. A ‘‘true-cut’’ type biopsy needle is needed for kidney or deep tissue biopsies. Surgical laparoscopy often requires a vast array of instruments designed for specific indications. Common instruments include grasping forceps, scissors, aspiration tubes, and clip applicators. Certain specialized instruments, such as stapling devices, are generally 10 mm or larger in diameter. Many of the biopsy and surgical instruments also have a capability for monopolar electrosurgery at their distal tip.
Basic laparoscopic technique Preparation, restraint, and surgical considerations Once the decision is made to perform a laparoscopy, there are a number of presurgical details and considerations to be made. The patient should be fasted for at least 12 hours before the procedure, and the urinary bladder should be evacuated to prevent puncture with trocars or cannulae. Laparoscopy is commonly performed using general gas anesthesia. Most patients tolerate general anesthesia well during laparoscopy; however, it is expected that the pneumoperitoneum from carbon dioxide insufflation will increase intra-abdominal pressure and may interfere with excursions of the diaphragm [7,8]. In some situations, the authors perform diagnostic laparoscopy using only heavy sedation in conjunction with local anesthesia at the entry sites. It is advisable to avoid high intra-abdominal insufflation pressures or excessive tilting of the surgical table, which would apply undue pressure from the abdominal organs on the diaphragm. In cases in which ventilation becomes compromised, assisted ventilation is necessary. The objectives of the laparoscopy procedure must be determined to select the appropriate cannula portal placement sites. The two most common approaches are the right lateral approach and midline approach. The right lateral approach is the recommended approach for diagnostic evaluation of the liver, gallbladder, right limb of the pancreas, duodenum, right kidney, and right adrenal gland. A ventral approach is often useful for many operative procedures and offers good visualization of the liver, gallbladder, pancreas, stomach, intestines, reproductive system, urinary bladder, and spleen. In the ventral approach, the primary portal is placed on or adjacent to the midline near the umbilicus. A disadvantage of the ventral approach is that the falciform ligament may hinder visualization of the anterior abdomen, especially in obese animals. A left lateral approach may be used, but the spleen lies directly under the normal entry sites, and there is the potential for splenic trauma by a trocar. With any approach, the entry site may be modified by moving either cranial or caudal to give adequate working space for the laparoscope as well as for the procedure to be performed.
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Technique The first step in laparoscopy is to establish a pneumoperitoneum before cannula placement. This begins with placement of the Veress needle either adjacent to the cannula portal sites or in the same site to be used by the first telescope portal. Once the needle passes through the abdominal wall, one should make sure that the Veress needle is actually in the abdominal cavity and is not retained in the muscle planes of the abdominal wall or penetrating an abdominal organ. Inadvertent insufflation in the subcutaneous tissues with carbon dioxide makes the procedure almost impossible to continue. To ensure that the Veress needle is in the abdominal cavity and not within an organ, the ‘‘hanging drop test’’ can be performed. This requires placing a drop of saline in the hub of the Veress needle and then lifting the abdominal wall with the needle shaft. The negative pressure within the abdominal cavity pulls the drop of saline into the needle. This finding confirms that the needle is in the peritoneal cavity. Insufflation of gas into a mass, organ, or vessel can result in fatal air emboli [9]. The Veress needle is then attached to the automatic insufflator. When the abdomen is adequately distended with carbon dioxide, it becomes tympanic on palpation. The abdominal pressure should be no greater than 15 mm Hg, and in most cases, 10 mm Hg is adequate to maintain abdominal distention and perform laparoscopy in small animals. A cannula unit that receives the telescope is then placed through the abdominal wall [10]. The entry site is determined, and an incision is made through the skin large enough to accommodate the cannula. The trocarcannula unit is then passed through the abdominal wall using a twisting and thrusting motion. One can hear a hollow ‘‘pop’’ and the sound of hissing air through the trocar once it has entered the gas-distended abdomen. Immediately after abdominal entry, the sharp trocar is removed from the cannula to prevent possible organ trauma. After initial cannula placement, the telescope is prepared for entry into the abdomen. The light cable is then attached to the telescope, and the light guide cable is attached to the light source. A videocamera is next attached to the telescope and focused to give a sharp clear image. The telescope is now advanced through the cannula and into the abdomen. Frequently, the image becomes blurred as the telescope enters the abdominal cavity as a result of tissue, fluid, or blood contaminating the lens as the telescope is passed through the cannula or from condensation on the lens as a result of temperature change. When this occurs, the tip of the scope is simply cleaned by carefully wiping the tip against abdominal tissues, such as the intestine. If the image is still blurred, the telescope is removed and cleaned using saline-soaked gauze. Once the telescope is in the abdominal cavity, careful examination of the contents is performed. Next, the site of entry for the second (accessory) portal is selected. This location depends on the ancillary procedures that are
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to be performed. The technique for placement of the accessory cannula involves visual laparoscopic control, viewing the trocar entry from inside the abdomen. Once the approximate entry site is determined, the abdominal wall is depressed with a finger and the site is viewed internally, identifying the palpation site. The entry site is then assessed to ensure that underlying organs will not be traumatized during trocar entry. The second cannula is then placed through the abdominal wall as described in the procedure for placement of the first telescope cannula, except this time, one watches the trocar entry viewed internally. Once the cannula has entered the abdomen, the trocar is removed. Exploration of the abdominal cavity is assisted by using the palpation probe to ‘‘feel’’ and move the organs as needed. When the probe or any instrument is passed into the abdomen, it should be viewed as it exits the cannula, and it is then directed to the area of examination. Instruments should never be blindly passed into the abdomen but rather viewed internally as they pass through the cannula and directed to the area of interest. Using this technique prevents serious tissue trauma by the probe or other accessory instruments. At the conclusion of the laparoscopic procedure, the instruments and telescope are removed and the pneumoperitoneum is allowed to escape. The cannulae are then removed, and the puncture sites are sutured in a routine manner, concluding the laparoscopic procedure. For postoperative pain management, we generally infiltrate bupivacaine local anesthesia in the trocar-cannula sites and prescribe systemic analgesia.
Basic laparoscopic biopsy techniques Liver biopsy Laparoscopic liver biopsy is considered by many to be the preferred method of obtaining a liver biopsy [10,11]. Other diagnostic modalities often do not provide sufficient information on the liver. One is able to view not only the liver but adjacent organs as well. A right lateral approach for evaluation of the liver, extrahepatic biliary system, and right limb of the pancreas is recommended. Using this approach, one is able to examine greater than 85% of the liver surface, take directed tissue biopsies, and monitor for excessive bleeding. We recommend using 5-mm oval cup biopsy forceps for the liver [12]. A recent study emphasized the benefit of laparoscopic cup biopsies when two 18-gauge needle biopsies were compared with the laparoscopic cup biopsies [13]. Before liver biopsy, the coagulation parameters are generally evaluated, including bleeding time. Although coagulopathies are a relative contraindication to liver biopsy, the coagulation status does not necessarily predict whether the patient will bleed from a liver biopsy.
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Fig. 1. Biopsy of the liver with cup biopsy forceps.
The biopsy forceps are directed to the area of the liver to be sampled. Either an edge of the liver or the surface of the liver can be biopsied with forceps (Fig. 1). It is always important to biopsy three to four areas of the liver, including areas that appear normal as well as those that appear abnormal. We generally hold the cups tightly closed for approximately 15 to 30 seconds before pulling the sample away from the liver. Some have suggested that biopsies taken at the edge of the liver may not reflect pathologic findings of deeper samples, because the subcapsular tissues are more reactive and fibrotic. The biopsy area is then closely monitored for excessive bleeding. Generally, most biopsy sites do not bleed much. If bleeding is considered to be excessive, several steps should be taken. The palpation probe can be placed into the biopsy site, with pressure applied over the area with the tip of the probe. Alternatively, a small piece of saline-soaked Gel-Foam (Pharmacia and Upjohn Company, Kalamazoo, MI) can be placed into the biopsy site using either laparoscopic grasping or biopsy forceps. These options are sufficient to control excessive bleeding. Pancreatic biopsy Laparoscopic forceps can also be used to biopsy the pancreas. We generally find pancreatic biopsies to be free of complications, and a study evaluating laparoscopic pancreatic biopsies in normal dogs found no postoperative complications or indications of secondary pancreatitis [12,14]. We believe that the punch type biopsy forceps work well for pancreatic biopsies; however, the cup biopsy forceps can also be used (Fig. 2). To obtain a pancreatic biopsy, the right lateral approach is preferred. This approach gives an excellent view of the duodenum and right limb of the pancreas as well as the extrahepatic biliary system and liver. The left limb of the pancreas is more difficult to examine from the right lateral approach,
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Fig. 2. Pancreatic biopsy taken from a normal pancreas using punch type biopsy forceps.
however. The biopsy site selected should be at the edge of the pancreas and away from the pancreatic ducts that traverse the center of the gland and subsequently enter the duodenum with the common bile duct. We generally take only one or two representative biopsy sample of the pancreas unless multiple lesions are present. Renal biopsy Laparoscopy is well suited for the evaluation and biopsy of the kidney [15,16]. To biopsy the kidney, we use an automatic ‘‘core type’’ biopsy needle (Vet-Core Biopsy Needle [16-gauge diameter]; Cook Veterinary Products, Bloomington, IN). The advantage is direct visualization of the kidney, which allows the operator to navigate the biopsy needle to the desired site to be sampled as well as to monitor for excessive postoperative bleeding. Before a kidney biopsy, adequate renal evaluation is necessary, including such considerations as renal excretory function, ultrasonography, or intravenous urography. This is important to determine which kidney to sample. Unless there is a specific indication to biopsy the left kidney the right kidney is preferred because it is less movable. A left kidney biopsy through a left lateral approach is more difficult because of the location of the spleen underlying the usual cannula entry site. Using a right lateral midabdominal telescope placement, the right kidney is easily visualized (Fig. 3). The authors then always place a second cannula so that a palpation probe is available to provide tamponade at the biopsy site. The palpation probe is placed in the abdomen near the kidney. Once the area of the kidney to biopsy is determined, a biopsy needle is directed to the
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Fig. 3. A view showing the right kidney from a right lateral approach. Also seen are the vena cava, portal vein, and caudate lobe of the liver. The right kidney is less movable and easier to biopsy.
site. This involves external palpation of the right midparalumbar region caudal to the last rib so as to select the location for the needle to transverse the abdominal wall. While viewing with the telescope internally, one palpates the abdominal wall with a finger for selection of an appropriate entry site. Next, a 2-mm skin incision is made at the desired entry site, and the needle is directed into the abdominal cavity and to the kidney. The usual location of sample collection is from the cranial or caudal pole of the kidney, being careful to obtain predominantly cortex with little medulla. The biopsy needle is seated through the renal capsule, and the needle is fired. The biopsy needle is then removed from the abdominal cavity. There are generally several milliliters of blood flowing from the biopsy site, and the palpation probe is quickly moved over the bleeding area, with pressure is applied for several minutes. Additional samples are taken if the first sample is not considered to be suitable. There are several precautions to keep in mind when obtaining a renal biopsy. First, the patient should not have been given drugs to increase renal blood flow (ie, dopamine), and the needle entry site through the abdominal wall should be caudal to the diaphragm. If the needle penetrates the diaphragm, an iatrogenically induced pneumothorax may result from leakage of the pneumoperitoneum into the thorax. Finally, one should avoid directing the needle deep into the kidney and involving the corticomedullary junction of the kidney, where the large arcuate vessels are located.
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Intestinal biopsy Small intestinal biopsies can be obtained with the laparoscope using the technique of grasping and then exteriorizing that portion of intestine through the abdominal wall. The intestinal biopsy sample is then obtained from the exteriorized bowel as would be done with a standard surgical biopsy [17]. The technique involves using 5-mm atraumatic grasping forceps with multiple teeth to grasp the intestine at the site to be sampled. It is often necessary to ‘‘run’’ the bowel using two grasping forceps to select a location to biopsy. Once the location is determined, the antimesenteric border of the intestine is firmly grasped with the forceps and the intestine is pulled to the cannula. A scalpel blade is then used to increase the cannula incision sufficiently so as to exteriorize the loop of bowel. One can watch the scalpel blade internally enter parallel to the cannula shaft and then cut away from the cannula to increase the incision length. Once the cannula incision is extended, a 3- to 4-cm loop of intestine is exteriorized and stay sutures are used in the intestine to prevent it from falling back into the abdominal cavity (Fig. 4). A small full-thickness biopsy is obtained in the same manner as one would use when performing an open abdominal surgical biopsy. The intestine is then returned to the abdominal cavity.
Fig. 4. After identification of the loop of bowel to biopsy, 5-mm atraumatic grasping forceps with multiple teeth are used to grasp the jejunum. The loop is exteriorized through the abdominal wall at one of the cannula sites. A stay suture is placed in the loop as soon as it is exteriorized.
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The intestinal biopsy should be the last laparoscopic procedure to be performed, because the pneumoperitoneum is lost during the procedure. If additional intestinal biopsies or other laparoscopic procedures are to be performed, the trocar-cannula must be reintroduced through the abdominal incision and the pneumoperitoneum re-established. A technique for multiple biopsies of the intestine using a serosal patch graph has also been described [17]. This technique involves retaining each segment of bowel biopsied using stay sutures after exteriorization and biopsy. The different biopsy sites are then sutured together to create a serosal patch graft. Other biopsy techniques A number of other biopsy techniques can also be performed with laparoscopic direction. These include biopsy of mass lesions, lymph nodes, the spleen, and the adrenal gland. Splenic biopsies are generally safe to perform using the cup type biopsy forceps or a biopsy needle. The technique, precautions, and coagulation control methods are the same as those described for a liver biopsy. Adrenal biopsies are sometimes performed when an adrenal mass is identified. Care should be taken, because bleeding after adrenal biopsy is common and hemostatic precautions are usually necessary. Cup forceps are used to obtain adrenal biopsies. Laparoscopy may also be used to determine the cause of unexplained abdominal effusion. The fluid is aspirated under endoscopic direction to enable examination of the abdominal contents. Surgical laparoscopy There are a number of minimally invasive surgical procedures that the authors currently perform using laparoscopy. A complete description of these surgical techniques is beyond the scope of this article, and the reader is advised to refer to other publications covering surgical techniques. Most of these surgical procedures require multiple trocar-cannula portals, specific laparoscopic surgical instruments, loop ligatures, clip applicators or monopolar electrosurgery. The techniques described are the primary procedures to be used for laparoscopic surgery in veterinary medicine. Feeding tube placement Duodenostomy or jejunostomy feeding tubes can be placed using the laparoscope simply by exteriorizing a piece of intestine through the abdominal wall and inserting the tube externally [17]. The technique of bowel exteriorization is similar to that described for intestinal biopsy. The intestine must be pexied to the abdominal wall in conjunction with the tube placement. A gastrostomy feeding tube can also be placed using the laparoscopy by simply by exteriorizing the body of the stomach through the left abdominal wall and then inserting the tube externally after a gastropexy.
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Gastropexy A preventive gastropexy is used for high-risk gastric dilation-volvulus in animals. Laparoscopic gastropexy is performed by exteriorizing the pyloric antrum region of the stomach through the right abdominal wall [18,19]. The animal is placed in dorsal recumbency, and the telescope portal is placed on the midline at the level of the umbilicus. The instrument portal for the grasping forceps is placed 2 cm behind the last rib on the right side and at the junction of distal and proximal third of the last rib. A portion of the gastric antrum is exteriorized, and an incisional gastropexy is performed to develop the serosomuscularis flap that is then pexied to the transverse abdominal muscle. Ovariohysterectomy Ovariohysterectomy can be performed using laparoscopy in most medium- and large-sized dogs [20]. Limitations of laparoscopic-assisted ovariohysterectomy relate to the size of the patient, because the space in the abdominal cavity of small animals makes the procedure technically difficult. The advantage of laparoscopic ovariohysterectomy is the perceived rapid patient recovery after the procedure. Ovariohysterectomy is performed with the animal positioned in dorsal recumbency. Both ovarian pedicles are dissected and ligated. The ovarian pedicle can be ligated with either a suture or vascular clips (Fig. 5) [21]. Next, a pretied loop of suture (Endoloop Suture or Loop Ligature, Endoloop PDS II, Ethicon Inc, Somerville, NJ) is placed in the abdominal cavity through one cannula. The ovaries and uterine horns are then passed through the loop. The loop is tightened down at the level of the cervix (Fig. 6). The uterus is transected, and both the uterus and ovaries are removed through one of the cannula holes that has been enlarged. Cryptorchid surgery A testicle that is located in the abdominal cavity can be removed easily using laparoscopy [22]. Laparoscopic vasectomy can also be performed by means of this technique [23]. The dog is placed in dorsal recumbency, and the table is tilted with the dog’s head in the lower position. Gravity then displaces the abdominal organs in the cranial abdomen, which facilitates visualization of the internal inguinal canal. Internal inguinal rings are inspected to determine the presence of the vas deference and testicular arteries. If these structures are present, either the dog has already been castrated or the testicles are in the inguinal area. Absence of the vas deferens and testicular artery in the inguinal canal means the testicle is ectopic. The ectopic testicle is usually readily visible on entering the abdominal cavity. The vascular pedicle and the vas deference are ligated with a pretied suture or clips (Fig. 7). The ectopic testicle is transected and removed through one of the cannula holes.
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Fig. 5. (A) Ovarian pedicle exposed with caudal traction of the uterus. (B) Vascular clips have been placed on the ovarian pedicle.
Other potential surgical procedures Adrenalectomy, removal of remnants of ovarian pedicles, correction of hiatal hernias, and nephrectomy are other surgical procedures possible to perform using laparoscopy. Laparoscopic removal of pancreatic neoplasia,
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Fig. 6. Both uterine horns have been placed through an Endoloop. The Endoloop is tightened around the cervix. The suture is then cut, and the uterus is excised. The uterus and the ovaries are removed through one of the cannula holes that has been extended.
such as an insulinoma, is possible. Small animal surgical laparoscopy is limited only by one’s imagination and innovation as well as by the instrumentation available to accomplish the procedure [24,25]. Complications of laparoscopy The complication rate of laparoscopy is low. In a review of 360 consecutive cases involving diagnostic laparoscopy, the authors found
Fig. 7. Right cryptorchid testicle cranial to the bladder. An Endoloop has been placed around the pampiniform plexus.
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Box 4. Potential laparoscopic complications Anesthesia-related problems Veress needle/trocar insertion Vascular injury to abdominal wall Penetration of organs Perforation of hollow viscus Insufflation Subcutaneous emphysema Peritoneal tenting Inappropriate insufflation Pneumothorax Gas embolism Operative complications Bleeding Tissue injury Technical problems Lack of experience Equipment-related problems
a complication rate less than 2%. Potential complications are listed in Box 4. Serious complications include anesthetic- or cardiovascular-related death, bleeding, or air embolism [26].
Summary Laparoscopy is a minimally invasive technique for both diagnostic biopsy and surgical procedures. After the basic technique of laparoscopy is mastered and the appropriate indications are learned, these procedures become an easy and rewarding addition to any small animal veterinary practice.
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