Laparoscopy -A New and Rapidly

Advancing Field in Veterinary Science

LH Beierer and DM Burgess School of Veterinary Science University of Queensland, Qld 4072

Laparoscopy is a minimally invasive technique for exploration and manipulation of the internal structures and wall of the peritoneal cavity. The minimally invasive nature of the procedure, diagnostic accuracy, reduction in surgical stress, reduced patient morbidity and post-operative pain contribute to making this procedure a definite alternative to open surgical approaches in small animals. This nanative review will cover the equipment, technique, diagnostic and surgical applications, advantages, disadvantages and complications of small animal laparoscopy. Laparoscopy represents a major advancement in veterinary science and demonstrates a fmward thinking approach to patient care. [Beierer LH & Burgess DM (2009) Aust Vet Practit 39:1 0]

Minimally invasive surgical techniques are becoming increasingly prevalent in veterinary surgery as teclmology and client expectations continue to broaden. Laparoscopy is a minimally invasive technique for exploration and manipulation of the intemal structures and wall of the peritoneal cavity. The procedure involves insufflation of the abdominal cavity and placement of a rigid endoscope (laparoscope) through a portal positioned percutaneously in the abdominal wall. Once abdominal distension and visual access is attained, adjacent portals can be inserted and used for placement of a wide variety of instruments for both diagnostic and surgical procedures.

~aparoscopy is a growing discipline in veterinary sbience which promises significant advantages over traditional open surgical procedures. The minimally invasive nature of the procedure, diagnostic accuracy, reduction in surgical stress, reduced patient morbidity and post-operative pain contribute to making this procedure a definite alternative to open surgical

Ph: 07 3359 0777. Fax: 07 3359 0722. Email: Dave.Burgess@qldvetspecialists.com.au

approaches in small animals. This nanative review aims to critically evaluate published literature in the field of small animallaparoscopy.

The basic equipment required for laparoscopy includes: a laparoscope, light source, Veress needle, automatic gas insufflator, trochar-cannula unit and ancillary instruments (Jones 1990, Richter 2001, Monnet & Twedt 2003).

Light Source Light is transmitted fi'om a remote light source via a fibre-optic cable to the laparoscope (Fig 1). Commonly available light sources are 150W or 300W halogen or xenon powered and must provide sufficient illumination to satisfactorily view the abdominal contents in true colour. This can best be achieved with a xenon powered fibre optic light source, as it is brighter and provides the truest colours when compared to its halogen counterpart (Monnet & Twedt 2003).

Camera Video assisted laparoscopy (Fig 2) is now considered to be routine practice (Monnet & Twedt 2003) as it enables the entire surgical team to view the image simultane­ously, reduces operator fatigue, aids teaching and

enables recording of the procedure (Richter 2001). Currently available cameras come as a one or three chip model, the latter providing superior resolution necessmy for quality photo documentation but also are more expensive.

Laparoscope Laparoscopes (Fig 3) are rigid endoscopes which vmy in length, diameter and viewing angle. The conventional rigid endoscope optical system incorporates a series of convex lenses separated by large air spaces, but the recently developed Hopkins rod lens system utilises comparatively longer rods of glass and smaller air spaces. The advantages of the rod lens system are better image resolution, greater light transmission, a wider field of view and image magnification. They va1y from 2.7mm to lOmm outside diameter and can be fmward viewing (0 degrees) or angled (10, 25, 30, 45, 70, 90, 120 degrees). A 0 degree scope provides a direct fmward viewing ,area and is cmmnonly accepted as being more intuitively obvious as the object of interest is directly in front of the scope. However oblique angled scopes enable viewing in relatively inaccessible areas such as the dorsa-cranial aspect of the liver (Richter 2001).

Veress needle A Veress needle is used for initial gas insufflation of the abdominal cavity and consists of an outer cutting sheath which punctures through the abdominal wall and an inner spring loaded obturator that retracts into the cutting needle while penetrating the abdominal wall and extends beyond the sheath once through the peritoneum to provide a blunt protective barrier against perforation of abdominal organs.

Insufflator Gaseous insufflation of the abdomen provides exposure of the abdominal organs. Insufflation is performed via an automatic insufflator (Fig 4) which delivers gas at a prescribed rate to obtain a constant intra-abdominal pressure (IAP). A variety of different gases have been trialled for use in intra-peritoneal insufflation including carbon dioxide (C02), nitrogen (N2), nitrous oxide (N20), and helium (He). Studies of He (Wolf et al1994) and N2 (Gilroy & Anson 1987) have found them to be highly insoluble in blood and to pose a high risk for fatal gas embolism, a potential complication of laparoscopy.

Carbon dioxide is considered the gas of choice to prevent air embolism due to its high diffusability and rate of bodily excretion (Magne & Tams 1999, Richter 2001). Conjecture exists regarding the use of both C02 and N20 in peritoneal insufflation as both have been touted as the "gas of choice" ( El-Minawi et al1981, Fitzgerald eta! 1992, Gross et al1993, Ishizaki et all993a, Ishizaki et al1993b, Kotzampassi et all993, Katircioglu et all998, Aksoy et a! 2001). Carbon dioxide is associated with significant hypercarbia and respiratmy acidosis (El­Minawi et al1981, Grosset all993, Kotzampassi eta! 1993) while N20 is disadvantageous as it places limitations on the surgeon as electrocautery techniques, that support combustion, cannot be used (Duke et a! 1996). But, it is associated with insignificant changes in arterial carbon dioxide tension and arterial pH while C02 is associated with a significant rise in mterial carbon

dioxide tension and a significant decrease in arterial pH (El-Minawi et al1981).

Older or debilitated patients with pre-existing pulmonary disease are at risk of C02 retention and He may be a reasonable alternative as it is associated with significantly less hypercarbic or acidic changes than is C02 (Bongard et a! 1991, Fitzgerald et a! 1992, Kotzampassi et a! 1993). It is an inert and non­inflammatory gas and while posing a risk of air embolism, this can be reduced through an open (manual dissection to the peritoneum) technique of insufflation. Insufflation pressures below 20mmHg have been recmmnended for laparoscopy (Motew et al1973, Jones et al1985, Grosset a!l993, Duke et al1996).

In a controlled experimental study, assessing systemic haemodynamics through step wise increases in IAP (8, 12, 16mm Hg), the changes of decreased cardiac output, increased systemic vascular resistance and decreased hepatic blood flow were not evident at 8-12mmHg, but were significant at 16mmHg (Ishizaki et al1993b). In a randomised controlled study, of eight dogs with vmying lAP of 10-20-30mmHg, all induced cardiorespiratmy changes resolved rapidly(< 5 mins) when pressures did not exceed 20mmHg (Gross et a! 1993). Pressures greater than or equal to 15mmHg are currently recommended to minimise the effects of maintaining a pneumoperitoneum (Jones et a!l985, Gross et all993, Monnet & Twedt 2003).

Ports The trochar-cannula unit comprises of a sharp tipped trochar which is contained within a cannula. The cannula is used as an instrument or laparoscope pmial and the inside trochar portion is used to traverse the abdominal wall. Once into the abdomen, the sharp tipped trochar is removed and the laparoscope or instrument is inserted into the cannula. An air tight seal and leur-lock adapter is built into each trochar-cannula for continued insufflation of gas. A recent modification is the EndoTIP(tm)1 which works to displace muscle and fascia without puncturing or cutting and potentially removes the possibility of organ injmy by uncontrolled penetration.

All patients should be fasted for a minimum of 12hrs before the procedure, and their urinmy bladder should be evacuated (Richter 2001, Monnet & Twedt 2003). Evaluating pre-surgical coagulation status for animals undergoing laparoscopic intervention has been recommended (Jones 1990), but it is controversial (Richter 2001 ). Further studies need to be performed to quantify the association between in-vitro coagulation tests and real bleeding time following biopsy, especially of the liver, before their significance in the pre­laparoscopic examination can be determined.

Laparoscopy is performed under general anaesthesia in most cases; however, select procedures can reportedly be performed under heavy sedation and local anaesthesia at portal entry sites (Mollllet & Twedt 2003). For the extremely debilitated patient laparoscopy may be

1EndoTIP, Karl Storz

accomplished with just local anaesthesia with minimal or no sedation (Jones 1990).

The approach is chosen based on the procedure to be performed and pmial site placement is selected before the animal is prepared. General and procedural specific portal placement sites and approaches are described in

FIGURE 3: A selection of telescopes commonly used for laparoscopy (top to bottom), a 1 Omm diameter telescope with a 30 degree viewing angle, a IOmm telescope with a 0 degree viewing angle, a 5mm diameter telescope ~with a 30 degree viewing angle and a 5mm diameter telescope with a 0 degree viewing angle.

the literature (Richter 2001, Monnet & Twedt 2003). The abdomen is clipped extensively to facilitate conversion to an open approach, if required, and routine aseptic patient skin preparation and draping is performed.

A 1mm skin incision is made with a scalpel blade and a Veress needle is placed into the abdomen. A gas line is then attached from the insufflator to the Veress needle

FIGURE 5: Hepatic biopsy using a laparoscopic cup biopsy forceps. (* = Cup biopsy forceps; L =Liver.)

FIGURE 6: An ultrasonic current generatm:

FIGURE 7: A laparoscopic renal biopsy being pei.formed using a Tru-Cut biopsy needle. (* = Tm-Cut biopsy needle; K = Right kidney.)

and set to a constant intra-abdominal pressure. Once a pneumoperitoneum is established another skin incision is made, no larger than the diameter of the cannula, to allow for placement of the trochar-cannula unit. The trochar-cannula is placed into the abdomen via a twist and tluust motion. Once into the abdomen the trochar is removed to prevent organ damage and then the cannula is immediately advanced further. The laparoscope is placed tlu·ough this portal into the abdomen. The gas line is then transferred to the cannula stop-cock and the Veress needle is removed under direct visualisation. Additional instmment pmials can then be inserted under direct vision through the laparoscope, in combination with external palpation, to prevent organ damage.

On completion of the procedure a final examination is made of the abdomen for unsuspected trauma or abnormal bleeding from biopsy or therapeutic intervention sites. Suction can be used to eliminate any remaining free fluid. Once the abdomen has been satisfactorily evaluated and no complications are present, all instruments and the laparoscope can be removed from the abdomen and the valves on all cannulas are opened. Gentle pressure is placed onto the abdomen to force out any remaining gas and then all cannulas are removed. At entry sites, the rectus fascia, subcutaneous tissue and skin are then closed using standard techniques.

Liver Biopsy Numerous methods of obtaining liver biopsies have been described (Dalton & Hill1972, Lettow 1972, Bunch et al 1985, Jones et al1985, Van Den Ingh et a/1988, Richter 2001, Barnes et al2006, Vasanjee et al2006). Obtaining liver specimens is an invasive technique, but one that can achieve an aetiological diagnosis and help plan appropriate treatment regimes (Jones et al 1985). Biopsies may be collected using percutaneous, keyhole, laparoscopic (Fig 5) and conventional open surgical techniques (Jones et al1985). Specimens are obtained by using biopsy punches, biopsy needles, the ligature method, laparoscopic biopsy forceps and the ultrasonically activated scalpel (Fig 6) (Vasanjee et al 2006).

Laparoscopic biopsy offers a minimally invasive alternative to open surgical biopsy (Richter 2001 ), visual control, visual assessment of coagulation post-biopsy, the ability to select samples from multiple sites in the liver (Rawlings & Howerth 2004, Richter 2001) and the ability to simultaneously survey other abdominal stmctures (Jones et al 1985). Laparoscopy is often the preferred biopsy technique in animals with either coagulation or wound healing deficiencies (Rawlings & Howerth 2004). However, laparoscopy is inferior in detecting intra-hepatic lesions and ultrasonography may be preferred in this instance (Rawlings & Howerth 2004). A blinded prospective case series of 124 dogs and cats undergoing 18 gauge needle biopsy (simulating ultrasound-guided biopsy) and simultaneous surgical wedge biopsy (similar in size to laparoscopic biopsy, defined in the paper as the definitive histopathologic diagnosis) found a poor correlation, 48% (59 of 124), between morphologic diagnosis on needle biopsy to the

definitive finding (Cole et al 2002). In that study, the histopathologists were blinded from the clinical data associated with tissue samples and the disparity between interpretations was likely associated with obtaining smaller tissue samples during needle biopsy and indicates the superiority of laparoscopic biopsy when compared with ultrasound guided needle biopsy.

Vasanjee et al (2006) compared five different hepatic biopsy techniques in a study of 12 dogs; biopsy punch (4mm Bakers Biopsy2), biopsy needle (16g" Tm-cut3),

ligature method, clamshell laparoscopic biopsy forceps and ultrasonically activated scalpel; all but the biopsy needle yielded adequate samples for histopathology. The study, however, failed to define "adequate for histological evaluation" and did not adequately blind the pathologists. Only 19% of the biopsy punch samples contained less than six portal triads; this is of concern when hepatic pathology involves the portal-triads, as human studies have shown greater than six-to-eight portal triads are required for diagnosis of human liver disease (Bravo et al 2001 ). The number of pmial triads required for diagnosis of canine liver disease has not been quantified but it is likely to be similar to this human figure.

Laparoscopy can also be used in animals with ascites to obtain liver biopsies without the accompanying protein loss that is inherent with a traditional laparotomy (Rawlings & Howerth 2004). However paracentesis is often performed before laparoscopy to evacuate cloudy fluid which readily impedes visualisation and increases anaesthesia time (Richter 2001).

Renal Biopsy Current renal biopsy techniques described for use in small animals include percutaneous and surgical approaches (Grauer et al 1983, Wise et al 1989, Rawlings et al2003a, Rawlings & Howerth 2004, Vaden 2005). Percutaneous methods include blind/palpation, laparoscopic (Fig 7), keyhole and ultrasound guided techniques. Wedge and needle biopsies can be obtained via a laparotomy (Vaden 2005). A ,prospective experimental case series of 36 dogs, comparing laparoscopy-guided biopsy and variations o'fthe keyhole biopsy technique found no statistical difference between specimens obtained via either method (Wise et all989). This was despite the risk of artefact associated with considerable displacement of the kidney, as sometimes occurs with the keyhole technique (Vaden 2005). This study was unable to quantify the post-biopsy complication rate as all dogs were euthanised immediately after the final biopsy and the primary outcome measure was not dependant on diagnostic yield. Instead, suitable tissue was defined as core biopsies which contained greater than or equal to five intact glomemli and adjacent tubules. Another prospective experimental study comparing 14 gauge and 18 gauge ultrasound guided percutaneous and laparoscopic needle kidney biopsy specimens concluded that 14 gauge biopsy specimens, obtained laparoscopically, had a significantly higher mean number of glomemli than the mean number of glomemli obtained using ultrasound-

2Baker-Cummins, Miami, FL 3 Allegiance, McGaw Park, IL

guidance (Rawlings et a! 2003a). However, the authors are unaware of any clinical studies in dogs that document the required number of glomeruli in biopsy specimens required for an accurate histological diagnosis. All laparoscopic biopsies had transient and easily monitored haemorrhage whereas one ultrasound-guided sample had a large amount of haemorrhage (Rawlings et al2003a).

A retrospective case series of 197 needle biopsy specimens obtained via the keyhole technique (dogs) and blind percutaneous (cats) found a 96% correlation rate with necropsy diagnosis in 101 cases and all cases of incorrect diagnosis were attributed to a lack of focal lesions and lack of glomeruli in samples (Jeraj et a! 1982). Visual direction oflaparoscopic biopsy leads to a higher likelihood that diagnostic tissue will be obtained when focal lesions exist and provides direct observation of haemorrhage after biopsy (Grauer eta! 1983, Vaden 2005). Visualisation of the kidney can detect renal tumours, infarcts, petechiation and irregular renal surfaces, all of which can be missed by digital palpation with the keyhole biopsy technique (Grauer eta! 1983). Sedation and local anaesthesia requirements for laparoscopy are similar to those for the keyhole technique (Grauer et a! 1983). Surgical biopsy may be the prefened method in small dogs (less than 5kg) and those undergoing a laparotomy for another reason (Vaden 2005).

Pancreatic Biopsy Laparoscopic biopsy of the canine pancreas (Fig 8) was perfonned in 10 clinically normal dogs without incident. Biopsied tissue was deemed to be of satisfactory size and condition to allow for a histopathologic diagnosis by the attending pathologist (Hanington et a/1996). In a case series of 23 dogs that underwent laparoscopic biopsy of the pancreas, biopsies could not be obtained in four cases due to severe pancreatic atrophy or coalescence (Spillmann et a! 2000). In an early study, laparoscopic pancreatic biopsy was performed successfully in two dogs and the authors believe the speed with which the procedure can be conducted under sedation and local or general anaesthesia avoids some of the risks sunounding a laparotomy (Dalton & Hill 1972). An experimental case report described laparoscopic pancreatic biopsies in four healthy laboratmy beagles which were completed uneventfully, and without difficulty, providing satisfactory tissue for histopathologic examination. Two dogs were euthanised at seven and 21 days post-surgery and did not exhibit any permanent abnormalities in clinical health, haematology or biochemical parameters (Harmoinen et a/2002). Pancreatic biopsy is considered a relatively safe procedure for the diagnosis of pancreatic diseases with high diagnostic value (Spillmann et a! 2000).

Intestinal Biopsy A technique of laparoscopic-assisted small intestinal biopsy has been described (Rawlings et a! 2002a, Monnet & Twedt 2003). A portion of intestine is grasped and exteriorised through an extended trochar incision and a small full thickness biopsy (as per an open abdominal surgical biopsy) is obtained (Rawlings eta! 2002a, Monnet & Twedt 2003). In an evaluation of endoscopic (EB) and full-thickness biopsies (FTP) (obtained by laparotomy or laparoscopy), laparoscopy

was identified as an effective minimally invasive alternative to laparotomy for abdominal exploration. It was also useful for assisting in FTB of the stomach and intestine (Evans et a! 2006). In seven cats FTP was obtained with laparoscopic assistance and a laparotomy was performed in 15 cats and no surgical complications occurred after any of these procedures (Evans et:' a! 2006). However EB yielded incorrect or inconclusive results in as many as nine of 11 cats (Evans et a! 2006).

General Biopsy Barnes et a! (2006) successfully obtained laparoscopic biopsy of the liver, spleen, adrenal gland, pancreas, stomach, jejunum and bladder using laparoscopic or laparoscopic-assisted methods in 12 dogs. This suggests that laparoscopy can be used to obtain biopsies from almost all abdominal organs.

Oncological Applications Laparoscopy can be used to diagnose and stage abdominal tumours through direct visual inspection and allows directed biopsies (Richter 2001). Laparoscopy can facilitate oncological staging, where surgety is of no benefit or may be detrimental to compromised animals, by facilitating documentation of disease for further management (Johnson & Twedt 1977). They reported that laparoscopic evaluation to assess prognosis was valuable for detecting peritoneal and diaphragmatic metastases, following splenectomy in one patient while undergoing chemotherapy. A second dog that was receiving chemotherapy for a malignant mast cell tumour developed abnonnalliver function. In this case, laparoscopy facilitated non-invasive biopsy which revealed a lack of hepatic malignant invasion and chemotherapy-induced hepatopathy was subsequently diagnosed. Masses on the peritoneal surface (less than 1mm) can be visualised during laparoscopy despite being vety difficult to detect via traditional diagnostic methods (Richter 2001). While ultrasonography is used commonly for imaging of most intra-abdominal masses, laparoscopy does confer the advantage of direct visual examination of masses and for visually guided biopsies (Magne 1995).

Reproductive Evaluation Laparoscopy has been used to assess reproductive function in the bitch including ovarian changes (Wildt et a/1977a, Wildt et a/1977b, Wildt et a/1978, Wildt eta! 1979, Wildt et a/198lb), and is reportedly useful for the examination of ovaries, the uterus, the pelvic vagina and for the detection of pathological lesions (Seager 1990, Wildt eta! 1978). Applications, which may be superior to alternate techniques such as ultrasonography, have been investigated (Seager 1990) and include internal visual reproductive tract examination, collection of reproductive tract fluids and secretions, aspiration of ovarian follicular fluids and cysts, insemination of sperm directly into the uterus, uterine horn or oviduct and collection of ova by follicular aspiration. Additionally, intra-uterine insemination in the bitch has been performed with successful results (Silva et a/1995, Silva & Verstegen 1995). Although useful for detecting morphological ovarian changes, it does not allow precise determination of the time of ovulation (Silva et a/1996). Laparoscopic methods of male and female sterilisation are described later.

Ultrasound Assisted Diagnostics The advent of high frequency ultrasonographic probes designed to be introduced into the peritoneal cavity, enables operators to overcome the inability to assess the internal structure of organs during diagnostic and surgical laparoscopy (Penninck & Finn-Bodner 1998, Sanchez-Margallo et a! 2003, Spinella et a! 2006). Laparoscopic ultrasonography (LU), via a microconvex transducer located at the tip of a rigid probe, allows core biopsy or needle aspiration to be performed by guiding the needle into non-superficial lesions, where video endoscopic guidance alone is not sufficient (Spinella et a! 2006). Six dogs unde1went pre-surgical ultrasound examination followed by LU which aided in obtaining biopsies from three of the dogs with focal intra­parenchymal anechoic areas in the liver. One dog had an inhomogenous hypoechogenic mass crania-medial to the right kidney and two dogs had vascularised masses. In the two dogs, where post-biopsy haemoperitoneum was

FIGURE 8: Pancreatic cup biopsy obtained laparo­scopically. (* =Cup biopsy forceps; P =Pancreas.)

FIGURE 9: Intra-operative view of a uterine horn and OVGJ)I. Once visualisation of the ovmy is maintained, the swgeon can proceed with a laparoscopic ovariohyster­ectomy, ovariectomy or laparoscopic-assisted ovariohyster­ectomy. (*=Forceps; C =Descending colon; 0 =Left ovary; SL =Suspensory ligament; U =Left uterine hom.)

considered a high risk, LU allowed the needle to be guided into the neoplastic tissue avoiding the vascular lacunae (Spinella et a/2006). Additionally, LU permitted comparison between surface findings discovered by laparoscopy and the sonographic structural examination of the parenchyma (Spinella et a! 2006). In a study evaluating changes in characteristics of the gastroduodenal junction, during pyloroplasty performed laparoscopically, the authors found LU effective for morphological evaluation of the pyloric sphincter. With the addition of colour Doppler, it was useful for differentiating the common bile duct from the right gastric artery in clinically normal dogs (Sanchez­Margallo et a/2003).

Lymphangiography and Thoracoscopic Thoracic Duct Ligation Mesenteric lymphangiography, via a laparoscopic approach, was successfully performed in two of five dogs (Brisson et a! 2006) and could be combined with

FIGURE 10: Intra-operative view of a completed laparoscopic incisional gastropexy. (GP = Gastropexy; P = Pyloric antlum.)

FIGURE 11: Intra-operative vierv of a laparoscopically identified c1yptorchid testicle. Castration can be peJformed entirely laparoscopically or be converted to a laparoscopic­assisted procedure. (*=Forceps; B =Bladder; T =Left testis.)

thoracoscopic thoracic duct ligation in the treatment of canine chylothorax (Radlinsky et a! 2002). Direct mesenteric lymphangiography has been recommended as the imaging technique of choice for use before, and after, thoracic duct occlusion (Brisson et a! 2006). Laparoscopy enabled efficient identification of mesenteric lymph nodes in all dogs, however failure of contrast injection in three dogs occurred because of lack of stabilisation of the injected lymph node. Further studies are required to refine the procedure (Brisson eta! 2006).

Ovariohysterectomy and ovariectomy Numerous laparoscopic methods of female sterilisation have been described in the literature (Wildt & Lawler 1985, Minami et a! 1997, Dharmaceelan et a! 2000, Austin eta! 2003, Hamdane eta! 2003, Davidson et al 2004, Devitt et a! 2005, Hancock et al 2005) however they have not been widely adopted by veterinarians, due to the cost and complexity of laparoscopic equipment, the difficulty in mastering laparoscopic technique, the duration of laparoscopic procedures and the lack of knowledge about the benefits. Laparoscopic ovariohysterectomy (Fig 9) (Austin et al2003, Hancock et al 2005) offers a minimally invasive alternative to the traditional ovariohysterectomy (OVH) via a coeliotomy. Laparoscopic ovariohysterectomy (LOVH) can be performed as a complete laparoscopic procedure or via a laparoscopic-assisted approach. Laparoscopic-assisted OVH (LAOVH) techniques are able to maintain the minimally invasive attributes of laparoscopic technique while incorporating extracorporeal techniques to improve the efficiency of more complex procedures (Minami et a! 1997, Davidson et al 2004, Devitt et al 2005). Ovariectomy can also be completed laparo­scopically (Dhannaceelan et al 2000, Hamdane et a! 2003, Van Goethem et al 2003, Van Nimwegen et al 2005) and is being promoted as a relatively rapid, minimally invasive approach providing excellent observation of the genitourinmy tract and other viscera (Van Goethem et al2003).

Gastropexy Gastropexy is commonly indicated as a prophylactic procedure in large breed dogs that are susceptible to

gastric dilation-volvulus (GDV). Laparoscopic techniques for gastropexy (Fig 1 0) are aimed at circumventing the drawbacks of a laparotomy. A variety of laparoscopic gastropexy techniques have been described in the literature (Thompson et a/1992, Hardie et al 1996, Wilson et al 1996, Rawlings et al 2001, Rawlings 2002, Rawlings et al2002c ). Additionally, two incidents of laparoscopic-assisted de-rotation of the stomach and incisional gastropexy have been reported (Rawlings et al 2002c). Wilson et al (1996) compared laparoscopic and standard belt-loop gastropexy techniques in eight dogs, randomly divided into two groups of four, and found no statistical differences between biomechanical strength and surgical duration. In another study in which 14 dogs underwent laparoscopic stapled gastropexy (LG) and six dogs underwent incisional gastropexy (IG), the IG adhesions were found to be significantly stronger than the LG adhesions at seven days but at 30 days after surgery, the strength of the LG and IG adhesions were statistically equal (Hardie et al1996). The maximum tensile strength required for a pem1anent gastropexy is unknown (Levine & Caywood 1983, Fox et al 1985). Multiple breaking strengths of different gastropexy techniques have been documented (Table 1). These in vitro strengths demonstrate the adhesions produced by laparoscopic techniques are of similar strength to open gastropexy techniques.

Although laparoscopic correction of GDV in clinically affected dogs has been reported, the authors stipulated careful selection criteria. These included the ability to pass a stomach tube to ensure gastric deflation, lack of inh·a-gastric haemorrhage, as determined by the gastric contents, and haemodynamic stability after fluid resuscitation (Rawlings et al 2002c). Prophylactic laparoscopic-assisted gastropexy can feasibly be combined with laparoscopic ovariohysterectomy (Rawlings et al2002c ).

Cryptorchid surgery Multiple techniques for laparoscopic detection and removal of cryptorchid testicles (Fig 11) have been described (Gallagher et al 1992, Spinella. et al 2003, Miller et al 2004, Catone et al 2005, Le*v et a! 2005). Laparoscopy has also been used in the removal of a seminoma in a c1yptorchid dog (Pena et al 1998).

RESIDUAL STRENGTH COMPARISONS

• Gastropexy technique Open or Assessment Breaking strength Investigator laparoscopic {days after surgery) - mean ±SD (Newtons)

lncisional Open 21 60* Fox et al (1985)

lncisional Open 58 61.98 ± 14.65 Waschak eta! (1997)

lncisional ');1

Open 30 71.17 ± 12.11 Hardie eta/ (1996)

' 'Laparoscopic stapled Laparoscopic 30 72.93 ± 18.01 Hardie eta! (1996)

Laparoscopic Laparoscopic 50 76.55 ± 22.78 Wilson eta/ (1996)

Laparoscopic-assisted Laparoscopic 30 106.5 ± 45.6 Rawlings eta/ (2001)

Belt loop Open 50 109 ± 22.29 Wilson eta/ (1996)

Open 21 109* Fox eta/ (1985)

TABLE 1: Comparison of open and laparoscopic gastmpexy techniques with regards to the breaking strength at time of assessment. *SD not available

Laparoscopy offers two important advantages in animals with non descended testes: insertion of the laparoscope permits rapid exploration of the inguinal ring, to determine if the testicle has exited the abdomen, thereby enabling exploration to be limited to the inguinal region (if it has) and secondarily in animals with intra­abdominal testes it offers excellent visibility of important structures with minimal trauma to the patient (Miller eta! 2004). Also described was a laparoscopic­assisted technique which involves exteriorisation of the testicle and ligation externally, which simplifies ligation of the testicular vasculature and ductus deferens as well as forgoing the need for intra-corporeal ligation (Miller et al 2004). Other techniques include: intra-corporeal ligation with endoscopic ligating clips and transection of the vessels and the vas deferens between the ligation implants (Gallagher et al 1992, Spinella et a/2003) and applying a manual knot of absorbable material (Lew et al 2005). All, bf the intra-corporeal ligation techniques described involve the use of an extraction bag in which to place the testicles prior to removal (Gallagher et al 1992, Spinella et a/2003, Lew et al 2005). A report of 15 cases of laparoscopic cryptorchidectomy with intra­corporeal ligation detailed an average surgery time of about 15min, with the shortest procedure lasting llmin (unilateral) and the longest, 28min (bilateral). An extraction bag was used when the observed testes was enlarged, in order to restrict contact of possible neoplastic material with tissues of the abdominal wall (Lew et al 2005). A novel cryptorchidectomy technique forgoing abdominal insufflation in 10 dogs has been discussed which used a Y-shaped, abdominal wall, lifting device inserted in the abdominal cavity, through a 20mm incision, to complete a gasless, hand-assisted laparoscopic cryptorchidectomy (Catone et a! 2005). Laparoscopic techniques of male sterilisation via disruption of a fragment of the ductus deferens have also been described (Silva et a/1993, Wildt et a71981a).

A case of laparoscopic deferentopexy has been reported in the management of a male dog with refractory incompetence of the urethral sphincter mechanism (USMI) (Salomon et al 2002). The procedure improved the dog's clinical status, but some nocturnal, passive urine leakage persisted one month after surgery. When combined with the alpha-adrenergic drug, phenylpropanolamine, the incontinence resolved. The author commented that the laparoscopic procedure can be easily performed with low morbidity and high efficacy and is a simple, safe and quick technique.

Cystopexy Cystopexy has been used to prevent retro-flexion of the urinmy bladder in male dogs with a perineal hernia (Huber et al 1997) and in female dogs with a pelvic bladder as a treatment of USMI (Massat et a! 1993, White 2001). Eight male and seven female dogs were used to develop a technique for laparoscopic-assisted cystopexy which was subsequently performed in three client-owned dogs with retro-flexion of the bladder (Rawlings et al 2002b). All dogs were noted to have recovered rapidly after the cystopexy and were able to void urine normally. All of the dogs (except for one female) were euthanised within 30 days after surge1y and mechanical load testing was performed on the tissues.

The mean ±SD (Newtons) of the failing load was 89.8 ± 77.9 N which, on review of gastropexy load data, indicate a dependable pexy strength. No cystopexy load data exist in the literature. In two of the three clinical cases, both dogs had no recunences and normal urine voiding at nine and 10 months post-operatively. One dog was euthanised 11 days after surgery due

1 to

complications arising from leakage at a colopexy site, which was performed at the same time as the cystopexy.

For cystic calculi too large for removal by urohydropropulsion and not amendable to medical dissolution, surge1y has been recommended (Waldron 2003). Laparoscopic-assisted cystoscopy provides a minimally invasive alternative for removal of urinary calculi and is reportedly an easy procedure to perform. It also limits injmy to tissues that may be caused by an open laparotomy and cystotomy as well as potentially reducing urine contamination of the peritoneal cavity (Rawlings et al 2003b). According to the authors' knowledge no comparative evaluation of cystoscopy techniques exists.

Feeding Tubes Duodenostomy and jejunostomy feeding tubes can be placed by exteriorising a segment of intestine through the abdominal wall via a laparoscope and securing the tube externally (Rawlings et al 2002a, Hewitt et al 2004). Reported complication rates of the procedure are low and associated complications were mild and non-life threatening. In an experimental case series, laparoscopic­assisted, jejunal tube placement was completed in 10 dogs and via a traditional coeliotomy approach in five dogs. Reportedly the minor complications rates were not significantly different between groups (Hewitt et a! 2004). In an experimental case series of eight male dogs undergoing laparoscopic-assisted enterostomy tube placement no post-operative complications were detected (Rawlings et al2002a).

Porto-systemic Shunt Attenuation Laparoscopic porto-systemic shunt attenuation has been successfully performed in a clinical setting (Miller & Fowler 2006). Two dogs with extrahepatic portocaval vessels were confirmed using laparoscopic visualisation and attenuated with laparoscopically placed cellophane bands (Miller & Fowler 2006). Both dogs had minimal post-operative morbidity and biochemical evidence of adequate shunt ligation was present at follow-up examination (Miller & Fowler 2006). This result demonstrates that further evaluation of laparoscopy for identifying and banding portoazygos and intra-hepatic vessels are warranted (Miller & Fowler 2006).

Splenectomy Successful laparoscopic splenectomy has been reported in two canine and five porcine models utilising four-to­seven trochars (Thibault et al 1992). The reported surgeries took an average of 1hr 50min and did not require an open conversion (Thibault et a! 1992). All animals were euthanised atthe completion of the surge1y (Thibault et al 1992). While this htiinan clinical report did not describe the canine procedure in detail, iti does support further investigation into the feasibility , df this operation in a practical setting (Thibault et al 1992).

Pyloric Surgery Different laparoscopic pyloric surgery techniques have been trialled in dogs: Ramstedt pyloromyotomy (n=5) (Sanchez-Margallo eta! 2005); Heineke-Mikulicz (n=5) (Sanchez-Margallo eta! 2005) and Finney Pyloroplasty (n=6) (Sanchez-Margallo et a/2007). The technique was found to be technically feasible and was performed without complication. Laparoscopic pyloric surgery was found to be as effective as open surgery in reducing gastric emptying times in a study of 20 clinically normal dogs without surgical complication (Sanchez-Margallo et a/2005).

End-to-end Intestinal Anastomosis Successful laparoscopic end-to-end intestinal anast­omosis has been reported in 50 dogs and 30 pigs with only one reported complication (Bohm et a! 1993). Laparoscopic oncological right colectomy, with ~ntra­peritoneal ileocolic anastomosis, was. performe~ 1~ 21 dogs without any major intra-operative comphcatwns (Bohm et al1995b).

Other Procedures Other laparoscopic procedures have been described: laparoscopic cholocystectomy is now considered a routine therapy in humans (Chin et a/1997) and has been demonstrated in canine models (Moscovici et a! 1988, Bass eta! 1994, Zografakis eta! 2003); canine laparo­scopic liver resection (Machado et a! 2004, Frezza & Wachtel 2006); cryoablation for treatment of renal tumours (Stephenson et a! 1996); distal pancrectomy (Naitoh et a! 2002); and laparoscopic assisted end-on Jejunostomy for faecal diversion (Chandler et a/2005).

Laparoscopy has a wide range of indications in the healthy animal and in debilitated animals, as procedures can be completed with minimal sedation. However, laparoscopy has both relative and absolute contraindications in some disease states (Table 2).

CONTRAINDICATION$

Absolute

Septic Peritonitis (Monnet & Twedt 2003)

Obvious conventional surgical intervention is required (Monnet & Twedt 2003)

Diaphragmatic hernia (Jones 1990, Rothuizen 1985)

Abdominal Trauma (Steinman et a/1998)

Relative

Ascites (Jones 1990, Monnet & Twedt 2003)

Abnormal clotting times (Richter 2001)

Obesity (Monnet & Twedt 2003)

Ffoor patient condition (Monnet & Twedt 2003)

Extensive intra-abdominal adhesions (Rothuizen 1985, Jones 1990)

Severe cardiac dysfunction (Rothuizen 1985, Jones 1990)

Pyometra (Minami et a/1997)

Pregnancy (Jones 1990)

TABLE 2: Contraindications to lapamscopic procedures.

Laparoscopy is a minimally invasive technique as each incision only needs to be large enough to insert an instmment port and in doing so results in a marked reduction in risk of surgical wound dehiscence and eventration. The relative risk of eventration from a lcm laparoscopic incision compared to a 1 0-15cm lapar­otomy is significantly lower.

The changing face of human medicine and its wide adoption of minimally invasive surgery raises the potential for increased client acceptance and serves as a drawcard for clients and practitioners looking for an advanced level of surgical care. Laparoscopic images are automatically magnified 10 times which improves the tissue image, highlights detailed anatomy and provides the ability to work in a narrowed space. Laparoscopy also provides a new method for obtaining minimally invasive surgical biopsies without sacrificing specimen size.

A reduction in post-operative pain has been touted as a great benefit of laparoscopic procedures but has not been extensively investigated in the veterinary literature. A few comparative studies of laparoscopic and traditional OVH have been reported. Hancock et a! (2005) compared post-operative pain after OVH by harmonic scalpel4 assisted laparoscopic OVH (HALO) (n= 8) and OVH via median celiotomy and ligation (n=8). In a blinded assessment they found that HALO dogs exhibited less pain according to the University of Melboume Pain Scores (UMPS) than the traditional approach. No significant differences were observed between groups for heart rate, respiratory rate, temperature or for CPK and glucose concentrations. However, the traditional group had significantly hig~er mean UMPS than the HALO group at all post-operative times (2, 6, 12, 24, 48, and 72hr). Also, the HALO group tolerated significantly higher palpation pressures when assessing the mean nociceptive threshold measurements during all time periods except at 72hr. Another comparison between open (n=18) and laparoscopic OVH (n=16) (Davidson et a/2004) found significantly lower pain scores (2 of 10 subjective categories; 8 of 10 objective categories - UMPS) associated with laparo­scopic OVH when compared to the traditional approach at one or more post-operative time periods (2, 8 and 24hr). A comparison between open OV_H (n= 1 0) a~d LAOVH (n= 1 0) by Devitt et a! (2005) discovered pam scores for the traditional OVH were higher at all time intervals than for the LAOVH (pain system based on quantitative changes in physiologically param~ters a~d behavioural changes). Based on post-operative pam scores (maximum score attainable was 19), nine out of 10 dogs from the traditional approach required additional pain relief compared with none of the dogs from the LAOVH group (additional pain relief was indicated when any pain score reached greater than or equal.to six). Further investigation of post-operative pam, following a broad range of laparoscopic procedures, is indicated to confirm the post-operative pain benefits.

Laparoscopic handling of tissues has been suggested to

4Ethicon Endosurgery, Cincinnati, OH

result in less tissue trauma and less intra-abdominal contamination than with open procedures, giving rise to many claims that laparoscopy reduces the incidence of post-operative adhesions in people (Gutt et a! 2004). Abdominal adhesion formation in humans is reportedly associated with bowel obstructions, infertility and chronic abdominal pain (Schippers eta! 1998, Gamal et al2001, Gutt et al2004) and impedes surgical re-entry. A review of 15 clinical and experimental studies comparing surgmy via laparoscopy and laparotomy found a reduction in adhesion formation after laparoscopic surgery (Gutt eta! 2004). This conclusion was drawn 11-om a "preponderance of evidence, rather than a systematic analysis" as a meta-analysis was impossible to conduct due to the variability of the studies in regard to the design, animal model and adhesion scoring system (Gutt et al2004). This result supports the safety of surgical re-ently following laparoscopy (Gutt et al 2004) and the finding that laparoscopic procedures can be repeated frequently (Wildt 1980).

Human clinical observations following laparoscopic surgery indicate a shorter period of post-operative ileus, than after conventional surge1y, as a result of less induced abdominal trauma. In an attempt to objectively assess this hypothesis, numerous studies have compared post-operative gasti·ointestinal motility following open and laparoscopic cholecystectomy (Ludwig eta! 1993, Schippers et al1993, Tittel et al1995, Hotokezaka et al 1996a), colonic resection (Bohm et al I995a, Hotokezaka et al 1996b, Carlson & Frantzides 1997, Davies et al 1997, Tittel et al 2001) and distal pancreatectomy (Naitoh et al 2002). Assessing the electromyographic activity of the gastrointestinal tract or transit of radionuclide spheres several studies support the claim of reduced post-operative "physiological ileus" (Schippers et al 1993, Bohm et al I995a, Tittel et al 1995, Hotokezaka et al1996b, Davies et al1997, Tittel eta! 2001, Naitoh eta! 2002). However, other studies' conclusions were in direct contrast, finding no significant difference in post-operative gastrointestinal electromyographic activity after laparoscopic and conventional surge1y (Ludwig et al 1993, Carlson & Frantzides 1997, Tittel et al 2001). The disagreement between these studies demonstrates the limitations of clinical parameters to adequately define supposed benefits and there is demand for alternate techniques to comparatively assess gastric motility between approaches.

Increased peritoneal C02 pressure has been shown to reduce bleeding time following splenic capsule injmy (Papp et al 2003) suggesting that it may enhance spontaneous haemostasis during laparoscopy with a pressurised pneumoperitoneum.

Laparoscopic procedures are believed to result in a reduced surgical stress response when compared to the traditional open approaches. The biochemical stress response was evaluated in 35 dogs undergoing laparoscopic (n=12) and open surgical nephrectomy (n=12) against an open surgery sham (n=6) and pneumoperitoneum only (n=5) (Marcovich et al 2001). Serum concentrations of cortisol and glucose were chosen as the biochemical stress markers as they are reportedly more accurate than subjective assessments.

However, the serum glucose concentrations showed no significant pattern of variability and were omitted from the results (Marcovich et al2001). It was concluded that "cortisol concentrations were consistently higher at the time of skin closure in animals that underwent laparoscopic nephrectomy than in those that had open surge1y; but overall, cortisol decreased signific~ntly more rapidly in the laparoscopic group than in the open surgery group" (Marcovich et al2001). Whether this rise in cortisol in the laparoscopic groups is attributed to noxious stimulus or is an indirect result ofhypercarbia is unknown and as such the significance of these results is difficult to interpret. Laparoscopic and conventional distal pancreatectomies were performed and compared in a group of 10 randomly assigned dogs. Serum cortisol levels were found to rapidly return to normal at 8hr after the trauma onset in the laparoscopic group while remaining significantly higher in the traditional group (Naitoh eta! 2002). However, the peak cortisol levels (at 4hr) were not different between the groups. In the same study, interleukin-1 levels were found to be significantly higher in the conventional group when compared to the laparoscopic approach (Naitoh et al 2002). In the previously discussed laparoscopic ovariohysterectomy versus OVH study by Devitt et al (2005), the OVH group had significantly higher plasma cortisol concentrations at one and 2hr post-extubation. Although many would dispute the clinical significance of currently employed measures of biochemical stress, current evidence demonstrates a lower biochemical stress response of laparoscopic over open procedures.

Costs Costs are repeatedly put forward as a pertinent hurdle to the adoption of new technology however the potential for inward financial return also exists. The purchased equipment is not limited to laparoscopy but can also be used in thoracoscopy, rhinoscopy, cystoscopy and otoscopy. Expert opinion suggests that thoracoscopy and laparoscopy are very similar in technique, instrumentation requirements and basic indications and that thorascopic procedures are easier to perform (McCarthy 1999). Additionally, second-hand equipment can be sourced through hospital sales or surgical equipment companies.

Times Surgical time is a pressing issue for clinicians. A comparison between traditional and laparoscopic methods is best achieved when investigating methods of female sterilisation as these are amongst the most common laparoscopic techniques practised and is the area of research where the most information is available. Harmonic scalpel-assisted LOVH means surgical time (55.7min) was significantly longer than the traditional OVH (31.7min) (Hancock et al 2005). Mean surgical time for LOVH (120min; range, 47-175min) was significantly longer than for OVH (69min; range, 25-140min) (Davidson eta! 2004). The authors of this study believe that LOVH can routinely be performed in less than 1hr with experience (Davidson et al2004). Mean± SD duration of surge1y (initiation of pneumoperitoneum to final skin suture) for LAOVH (20.8 ± 4.0min) was not significantly longer than the traditional OVH (18.6 ±

3.9min) (Devitt et a/2005). Three alternative teclmiques of laparoscopic ovariectomy were compared and the mean time to complete the surgical procedure with each technique were 60.16 ± 1.64 min, 42.83 ± 1.40 min and 71.83 ± 1.62min (Dharmaceelan et a! 2000). These results are similar to the laparoscopic ovariectomy times of laser-assisted OVE (36.9 ± 9.7min) and bipolar­electrocoagulation OVE (39.3 ± 9.6min) (Van Nimwegen eta! 2005). A comparison between mono­polar (MEC) and bipolar electrocoagulation (BEC) teclmiques during OVE found the surgical time for MEC-OVE to be (52.7 ± 14min) and for BEC-OVE (40.8 ± lOmin) (Van Goethem et a! 2003). Although laparoscopic OVH and OVE techniques do reportedly take longer than the traditional procedures, the purported benefits and potential for improvement with experience support expansion to non routine procedures. It also serves to positively demonstrate veterinary surgeons' attitude towards surgical progression and providing best practice care.

Training The need for extensive training is also another perceived drawback of the technique. Training is definitely a necessity as the dexterity and haptic feedback required for instrument manipulation is unlike traditional surgical techniques. It is also important that trainees understand the physiology of, and access to, the pneumoperitoneum (Clavien et a/2005). There are no reported case numbers or training hours that correlate with operator proficiency. However, it is logical that surgeons master basic laparoscopic procedures (e.g. diagnostic laparoscopy) earlier in their training rather than advanced laparoscopic techniques. It may be suggested then, that by completing the former, surgeons can simultaneously provide income and training for the latter. Laparoscopic training techniques have been addressed in the literature (van Velthoven & Hoffmann 2006, Clavien et a! 2005). Outside of the operating room, training can be completed on animate (cadavers) specimens or purpose built inanimate laboratories. Inanimate laboratories en­compass video trainers; an opaque box with trochars allowing access to the interior wherein various physical materials can be manipulated in specific exercises (Clavi en et a/2005) and virhml reality. Training facilities can be accessed in human hospitals and in medical university facilities.

Limitations The inherent limitations of the equipment are that only a two dimensional image is provided, the laparoscopic port acting as a fulcrum (which restricts movement of the instruments) and only a restricted sense of tactile sensation is obtained (Richter 2001). While all of these are concerns, they are generally features that are overcome through experience.

Laparoscopy is no different to any other surgical procedure in that standard surgical complications occur. In addition to the standard set of surgical complications, reported laparoscopic complications are associated with gas embolisation, visceral perforation, gastrointestinal effects and the secondary impacts on the cardia-

pulmonary system. The specific complications of establishing and maintaining a pneumoperitoneum and obtaining biopsy specimens include: subcutaneous emphysema; omental emphysema; abdominal or diaphragmatic rupture secondary to over-distension; viscus perforation; solid organ trauma; and haemonhage following biopsy (McCarthy 2005).

Fatal air embolism is described as a complication of peritoneal insufflation in the dog (Gilroy & Anson 1987, Dion et a/1995). An experimental study was performed in five dogs in which the potential for C02 embolisation from a 1cm infra-renal vena cava (IVC) laceration was evaluated against the effect produced by C02 bolus injections into the jugular vein. In a total of 11 insults to the IVC under C02 pneumoperitoneum of 12-15mmHg, no major hemodynamic effects were detected (ie. no significant elevation of the pulmonary arterial pressure) (Dion et a! 1995). Air bubbles, as detected via transoesophageal echocardiography, were detected in the right heart cavities in only two of the insults (Dion et a! 1995). While the results of this study suggest that fatal gas embolisation does not result from a large venotomy, caution should still be exerted when laparoscopic surgery is perfonned near large veins. A single case report described almost immediate cardiopulmonary arrest following inadvertent Veress needle puncture of the spleen (Gilroy & Anson 1987). At necropsy, fatal air embolism was the confinned method of death as three 1 em bullae were found in the lungs and numerous air bubbles and crepitace throughout the spleen were present (Gilroy & Anson 1987). Carbon dioxide embolisation during laparoscopy is a recognised and potentially fatal complication and a large prospective case series, investigating air embolisation during a range of procedures, is required to truly quantify the risk.

A rapid reduction of jejunal blood flow was detected by laser-doppler flowmetry and a tonometric catheter leading to the conclusion that laparoscopy should be avoided where intestinal ischaemia is present, until further research is completed (Kotzampassi et a/1993).

The cardiovascular and respiratory effects of maintaining a pneumoperitoneum are a new challenge for practitioners to overcome. Many factors contribute to the circulatory instability during laparoscopy, the most important one being raised lAP (Kotzampassi et a! 1993). The severity of cardiopulmonaty disturbance is exacerbated at raised lAP and metabolic effects are influenced by the gas type used. It has been suggested that respiratmy minute volume is decreased by 30% with peritoneal insufflation during laparoscopy (Jones et a! 1985) while cardiac output is decreased by more than 40% in dogs with lAP between 20 to 40mmHg (Ivankovich et a! 1975). Insufflation pressure may increase cranial movement in the diaphragm, mechanically compressing the lungs and further reducing functional residual capacity and lung compliance (Gross et a! 1993). Elevated lAP may provoke an increase in systemic vascular resistance (Kotzampassi et a! 1993). An abundance of literature focusing on the cardiopulmonary effects of establishing a pneumoperitoneum exists but central to the issue is the recommendation that appropriate methods of monitoring anaesthesia be considered throughout laparoscopic

procedures. It has been recommended that a capnograph is a reasonable monitoring method for C02 and the physiological effects of hypercarbia, in medium sized dogs without cardiopulmonary disease, but arterial blood gas analysis may need to be performed in critical patients to better monitor for hypercarbia (Duke et a/1996).

Laparoscopy is a rapidly developing field of veterinary science that provides a minimally invasive approach to a wide variety of diagnostic and surgical procedures. Laparoscopy enables the procurement of abdominal biopsy specimens from a comprehensive range of organs and is associated with a high diagnostic yield, when compared with other minimally invasive techniques. Laparoscopy is used in abdominal tumour staging, reproductive evaluation and in combination with other diagnostic techniques. Surgical procedures including OVH, OVE, gastropexy, cryptorchid removal, cystopexy, placement of feeding tubes and porto­systemic shunt attenuation are just some of the procedures completed in dogs in a clinical setting. A broader range of surgical procedures has been completed in research models and provides scope for the development of advanced procedures. The list of procedural contraindications is small and the disadvantages of the technique are easy to overcome with experience. The advantages include: reduced patient morbidity, reduced biochemical stress response and reduced post-operative pain response, less tissue trauma and subsequent less adhesion formation, as well as a potential for the reduction in post-operative ileus. In the majority of patients surgical complications do not preclude laparoscopic procedures and are avoidable when the correct technique is employed. Laparoscopy represents a major advancement in veterinary science and demonstrates a forward thinking approach to patient care.

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Cats and their catch Should the ASAVA, the AVA group representative of small animals, also be instrumental in helping to create a system for the control of feral cats and to be seen to be influential in and supportive of that process? Their documented species catch now includes 186 native birds, 64 mammals, 87 reptiles and 10 frogs. Refuges, with exclusive fencing and selective shooting, seem to be the only way to make natural areas free of feral cats. www.epa.qld.gov.au, Nature Refuge, VollO Dec. 07