Association of Veterinary Soft Tissue Surgeons

Association of Veterinary Soft Tissue Surgeons Spring Scientific Meeting 1st April 2009 “What’s New and Hot?”

The AVSTS would like to thank the following sponsors for generously supporting this meeting:

1 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” The Association of Veterinary Soft Tissue Surgeons

Hall 7, International Convention Centre, Birmingham, UK 1st April 2009 What’s new and hot? PROGRAMME ------

09:00 – 09:30 Registration/ Tea, coffee & pastries (provided) Page

09:30 – 11:00 Abstract session  Emergency exploratory coeliotomy: retrospective Kelly Bowlt 5 study of 189 cases  Gastrointestinal foreign bodies in dogs and cats Graham Hayes 7  Total penile amputation and transpelvic urethrostomy Lea Liehman 8 in a Staffordshire bull terrier  Laparoscopic intrauterine artificial inseminations in Aracelle Alves 9 bitches using fresh and frozen thawed semen  Simultaneous bilateral caudal superficial epigastric Sam Woods 10 skin flaps in a cat  Biomechanical evaluation of different numbers, Aiden McAlinden 11 sizes and placement configurations of ligaclips required to secure cellophane bands

11:00 – 11:15 Tea / coffee (provided)

11:15 – 11:55 Vacuum assisted wound closure: a new tool in the Gary Ellison 12 management of troublesome wounds 11:55 – 12:05 Questions / discussion

12:05 – 12:30 AVSTS business meeting

12:30 – 13:20 Lunch in Hall 4 (provided)

13:20 – 13:40 Laparoscopy – abdominal exploration Eric Monnet 17 13:40 – 14:20 Surgical trends in the obstructive jaundiced patient. Stephen Mehler 23 14:20 – 14:40 Laparoscopy – liver. Eric Monnet 26 14:40 – 14:50 Questions/panel discussion.

14:50 – 15:40 Translumenal intervention – are there no limits? Rao Vallabhaneni 15:40 – 16:00 PSS – why use cellophane banding? Eric Monnet 28 16:00 – 16:10 Questions

16:10 – 16:25 Tea/Coffee (provided)

16:25 – 17:05 Ectopic Ureters – burning or blading? Stephen Mehler 31 17:05 – 17:25 Laparoscopy - cystoscopy. Eric Monnet 33 17:25 – 17:30 Questions / panel discussion

Times subject to change

2 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Main Speakers

Gary W. Ellison, DVM, MS, Diplomate ACVS

Professor and Service Chief, Small Animal Surgery,

University of Florida Health Science Center, Gainesville, Florida

[email protected]

Dr. Ellison earned his DVM from the University of Illinois in 1975. He completed a small animal internship at South Shore Veterinary Associates in Weymouth Massachusetts in 1976. Following this he practiced general small animal practice in San Francisco California. He completed a residency in Small Animal Surgery and received a MS in experimental surgery from Colorado State University in 1981. He practiced as a surgical specialist in San Diego California prior to becoming a Diplomate of the American College of Veterinary Surgeons and joining the faculty of the University of Florida in 1983. He is author or coauthor on 70 refereed publications and PI or CoI on 25 funded grants. His areas of interest include thoracic endoscopic and gastrointestinal surgery as well as feline renal transplantation. He currently is Professor and Chief of Small Animal Surgery at the University of Florida.

Eric Monnet, DVM, PhD, Diplomate ACVS Dr. E Department of Clinical Sciences Colorado State University, Fort Collins, Colorado

[email protected]

Eric Monnet graduated from veterinary school in Maisons Alfort, France in 1985. He worked for four years in a Paris private practice performing small animal medicine and surgery. In 1994, Dr. Monnet completed a small animal surgery residency at Colorado State University and concurrently finished a Master of Sciences degree. In 1997, Dr. Monnet received his PhD in Clinical Sciences studying cardiac efficiency in dogs. In 2003, he became a fellow of the American Heart Association.

Dr Monnet is currently a professor in small animal surgery (soft tissue) at Colorado State University. He has authored more than 100 articles and 15 chapters in various surgical textbooks. Dr. Monnet was the founding president in 2001-2003 of the Society for Veterinary Soft Tissue Surgery. He is the editor of the textbook: “Disease Mechanisms in Small Animal Surgery” (3rd edition).

3 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Steve J. Mehler, DVM, Diplomate ACVS

Assistant Professor of Small Animal Surgery

College of Veterinary Medicine, Michigan State University

Dr. Steve Mehler received his DVM from Michigan State University. He completed an internship in small animal medicine and surgery and a small animal soft tissue, orthopaedic and neurologic surgery residency at the University of Pennsylvania Veterinary Hospital. During his time at the University of Pennsylvania, Dr. Mehler spent a considerable amount of time working with the special species service. Dr. Mehler has published in many textbooks on surgical diseases of cats and dogs as well as exotic species; including, Reptile Medicine and Surgery, Current Techniques in Small Animal Surgery, Disease Mechanisms in Small Animal Surgery, Veterinary Clinics of North America, Trauma in Dogs and Cats, and the BSAVA Manual. His research and clinical interests include minimally invasive surgery, interventional radiology, medical and surgical interventions in exotics, and surgical diseases of the extrahepatic biliary tract in dogs and cats.

4 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Emergency Exploratory Coeliotomy: Retrospective Study of 189 cases (2001-2008)

Kelly Bowlt¹, Caroline Southerden, Stephen Baines²

1. Department of Clinical Veterinary Studies, University of Bristol, Langford House, Langford, Bristol, North Somerset, BS40

2. Department of Clinical Veterinary Studies, Royal Veterinary College, Hawkshead Lane, North Mimms, Hertfordshire, AL9 7TA.

Introduction:

Emergency exploratory coeliotomy is indicated where there is an acute abdominal disease process that requires surgery to provide a diagnosis, treatment and/or prognosis.

Materials and methods:

The medical records of 189 patients undergoing emergency exploratory coeliotomy at the Royal Veterinary College between November 2001 and May 2008 were reviewed retrospectively.

Results:

The study comprised 152 dogs and 37 cats. Eleven animals (6.3%, 8 dogs and 3 cats) underwent surgery for diagnostic purposes; 178 animals (93.7%, 144 dogs and 34 cats) underwent surgery for therapeutic purposes.

Ultrasound was performed in 70 dogs (46.1%) and 21 cats (56.8%), contributing to a diagnosis in 68 (97.1%) and 16 (76.2%) cases. Radiographs of the thorax, abdomen or both were taken in 117 dogs (77.0%) and 22 cats (59.5%), contributing to a diagnosis in 95 (81.2%) and 16 (72.7%) cases. Where radiography was inconclusive, ultrasonography contributed to a diagnosis in 17/22 (77.3%) cases.

Clinical pathological information included biochemistry/haematology (133/185 abnormal), activated partial thromboplastin time and prothrombin time (12/26 prolonged), FIV/FeLV (2/2 negative), urinalysis (9/19 abnormal) and urine culture (1/7 positive).

The median time from admission to anaesthetic induction was 12 hours (range 0.75-672) and the median surgical duration was 120 minutes (range 25-325), which was unrelated to species, age, weight or survival (p>0.05).

One hundred and forty animals (74.1%) survived until discharge following a median hospitalisation of 4 days (range 1-20). Nineteen animals (10%) were euthanased intra-operatively and 30 (15.9%) were euthanased/died following a median post-operative hospitalisation of 3 days (range 1-24). A greater proportion of cats (17/37, 45.9%) than dogs (32/152, 21.1%) did not survive (P= 0.004). Survival was less likely in animals undergoing surgery for diagnostic (8/11, 72.7%) rather than therapeutic (41/178, 23.0%) purposes (p<0.001).

Eighty-seven post-operative complications were seen in 71 animals (37.6%). Forty survivors (28.6%) developed complications related to surgery (n=13), anaesthesia (n=5) or disease process (n=22). Thirty animals were euthanased/died following complications related to surgery (n=3), anaesthesia (n=4), disease (n=23) or concomitant disease (n=1).

Post-operative complications were more likely in older animals (P=0.014) or following longer surgical procedures (P=0.005). Complications resulted in increased likelihood of death/euthanasia (p<0.001), but were not related to either diagnostic or therapeutic surgery.

Clinical relevance:

54.1% of cats and 78.9% of dogs undergoing exploratory laparotomy survived until discharge.

5 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Post-operative complications were more frequently associated with the disease process, increased age or increased surgical duration, resulting in more deaths in cats than dogs.

Table 1: Number of survivors/non-survivors, complications and final diagnoses of animals undergoing emergency exploratory laparotomy (S Survivor; NS Non-survivor; DR Disease related complication; AR Anaesthesia related complication; SR surgery related complication; UR unrelated complication).

Final Diagnosis Dogs Cats Complications

(S/NS) (S/NS) DR (S/NS) AR (S/NS) SR (S/NS) UR (S/NS)

Septic peritonitis 11/11 4/6 4/5 0/2 1/0

Gastrointestinal foreign body 26/3 2/1 3/1 2/0 2/0

Gastric dilation/volvulus 31/5 0 5/4 3/1 4/0

Urethral rupture 1/0 0 1/0

Dystocia 9/0 0 1/0 1/0

Haemoabdomen 14/5 1/1 3/1 1/0 3/0

Uroabdomen 6/1 3/1 0/1 1/0

Diaphragmatic rupture 3/0 4/0 2/0

Intussusception 4/5 2/1 1/3 2/0 1/2

Pyometra 6/0 0 1/0

Neoplasia 1/1 1/0 0/1

Urethral calculi 2/0 0 1/0

Trauma 2/0 1/3 0/2

Bile peritonitis 1/0 1/1 1/1

Urethral obstruction 0 0/1 0/1 0/1

Exploration following wound dehiscence 0 0/1 0/1

Orchitis 1/0 0

Mesenteric torsion 1/0 0

Splenomegaly 1/0 0 1/0

Biliary tract obstruction 0 0/1 0/1

No diagnosis achieved 1/0 0 1/0

Total 120/32 19/17 23/20 9/3 14/4 0/1

6 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Gastrointestinal foreign bodies in dogs and cats: a retrospective study.

Graham Hayes

RSPCA Greater Manchester Animal Hospital, 411 Eccles New Road, Salford M5 5NN

Objectives:

To establish predilection sites of obstruction and to investigate clinical factors associated with a poor outcome.

Methods:

A retrospective study of 208 consecutive cases over a 48 month period from first opinion practice.

Results:

Overall 91.3 per cent of cases recovered with higher survival rates from discrete foreign bodies (94.2 per cent in dogs and 100 per cent in cats) as opposed to linear foreign bodies (80.0 per cent in dogs and 62.5 per cent in cats).

English Bull Terriers, Staffordshire Bull Terriers and Jack Russell Terriers were over- represented.

In dogs 62.6 per cent of obstructions occurred in the jejunum but foreign objects were encountered at all points along the gastrointestinal tract.

A longer duration of clinical signs, the presence of a linear foreign body and multiple intestinal procedures were shown to significantly increase mortality.

Neither the degree of obstruction (partial or complete) nor the location of the foreign body were shown to have a significant influence on survival.

Clinical significance:

Prompt presentation, diagnosis and surgical intervention improves the outcome of gastrointestinal obstruction by foreign bodies. At surgery the minimal number of intestinal procedures should be performed to restore the integrity of the alimentary tract.

7 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Total penile amputation and transpelvic urethrostomy in a Staffordshire bull terrier – a novel surgical technique

Lea M. Liehmann Dr.med.vet. DipECVS, Ronan S. Doyle DipECVS

Davies Veterinary Specialists, Higham Gobion, Hertfordshire, UK

An 8-year-old, male Staffordshire bull terrier presented with a bleeding mass in the urethral mucosa 1.5 cm distal to the ischial arch.

Penile amputation, urethral resection and permanent urethrostomy have been described in similar cases for the treatment of urethral obstruction or disease (Davis and Holt, 2003). A perineal urethrostomy, however, requires at least a centimetre of remaining urethra distal to the ischial arch that can be anastomosed to the perineal skin. This fact limits the level of penile amputation and urethral resection. For conditions requiring a more aggressive resection, prepubic urethrostomy has been described as a salvage procedure. However, this has been associated with more postoperative complications such as urethral obstruction, urine scalding, urinary incontinence and a higher likelihood of urinary tract infections (Mendham, 1970, Kyles et al. 1996) compared to the more distal urethrostomies. After confirmation of a bulging lesion during urethroscopy, we performed penile amputation and urethral resection followed by a transpelvic urethrostomy using an ischial symphyseal osteotomy. This allowed the urethra to be freed from its pelvic attachments, spatulated, gently elevated and sutured to the overlying skin. A proximal tissue margin of one centimetre was achieved.

A similar surgical technique has previously been described as a salvage procedure for failed perineal urethrostomies in cats (Bernarde and Viguier, 2004) and was modified accordingly. Postoperatively the dog showed no signs of incontinence or urinary tract infection at the 3 months recheck. Mild urine scalding was observed for 10 days after surgery, but resolved afterwards. The excised lesion proved to be a vascular abnormality that had ruptured and caused severe and prolonged bleeding.

References

Bernarde A, Viguier E. (2004): Transpelvic Urethrostomy in 11 Cats Using an Ischial Ostectomy. Vet Surg 33:246-252.

Davis GJ, Holt D (2003): Two chondrosarcomas in the urethra of a German shepherd dog. J Small Anim Pract: 44, 169-71.

Kyles AE, Aronson M, Stone EA (1996): Urogenital Surgery. In: Lipowitz AJ, Caywood DD, Newton CD, Schwartz A (eds): Complications in Small Animal Surgery – diagnosis, management, prevention. Williams and Wilkins, p.455-525.

Mendham JH. (1970): A description and evaluation of antepubic urethrostomy in the male cat. J Sm Anim Pract 11: 709.

8 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Laparoscopic intrauterine artificial inseminations in bitches using fresh and frozen-thawed semen.

Hotston Moore A1; Alves AE2, Apparicio MF2, Mostachio GQ2, Motheo TF2, Vicente WRR2

1. Department of Clinical Veterinary Sciences – University of Bristol – Bristol / United Kingdom

2. Faculty of Agrary and Veterinary Sciences, UNESP campus Jaboticabal – SP / Brazil

Artificial insemination has been an important technique in assisted reproduction for wild species threatened with extinction. When intrauterine insemination is required the laparoscopic technique has show benefits for this procedure be minimally invasive, reducing the stress particularly in these species. The objective of this study was to compare fertility in bitches, following intrauterine insemination by laparoscopy using fresh or frozen thawed semen. Nine ejaculates from three males were used in a study of semen diluted in three different protocols utilizing TRIS (Tris-hidroximetilaminometano), T1 – Tris +glucose; T2 – Tris + fructose; T3 – Tris + Equex. T3 showed the best conditions of the spermatozoa post thawing, and was choosing for use in the inseminations. During natural oestrus, 20 bitches were inseminated on one occasion, 10 with fresh, and 10 with frozen-thawed semen. The time point of the insemination was calculated according to the rise of plasma progesterone levels. The bitches were subjected to general anaesthesia, and the laparoscopy technique involved the establishment of pneumoperitoneum with a Verres needle positioned 1 cm behind the umbilicus on the midline. A camera portal was placed 1 cm caudal to the umbilicus and two instrument portals were placed 4 cm caudal at the umbilicus and 2 cm lateral to the mammary glands, on either side. The uterus was grasped by forceps, and elevated against the ventral abdominal wall. A 18g catheter was inserted through the abdominal wall directly into the uterine lumen, and then 1.0 ml of either fresh semen containing 200 x 106 spermatozoa/mL, or frozen-thawed semen containing 80 x 106 spermatozoa/mL was injected. Ovariohysterectomy was performed 7 days after insemination, and the uterine tubes dissected and flushed using PBS solution in order to evaluate the presence of embryos. A total of 7 and 5 bitches were pregnant from the fresh and frozen-thawed semen group respectively. In conclusion laparoscopic intrauterine insemination appears to be a practical technique that may be of value for management of endangered species. In bitch, use of either fresh or frozen semen is effective.

9 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Simultaneous bilateral caudal superficial epigastric skin flaps in a cat.

S. Woods, A. I. de C. Marques, D. A. Yool

The University of Edinburgh, Royal (Dick) School of Veterinary Studies, Hospital for Small Animals, Easter Bush Veterinary Centre, Roslin, Midlothian, EH25 9RG

A 30 month old domestic shorthair cat was presented following unwitnessed trauma, with a highly contaminated circumferential avulsion of skin from the right hind limb. Surgical debridement was performed followed by daily dressing changes until the wound surface was covered with healthy granulation tissue. Simultaneous bilateral caudal superficial epigastric skin flaps were raised and used to cover the defect through a single bridging incision. Both the donor and recipient sites were closed without tension at the wound edges.

Moderate oedema of the limb developed post-operatively but resolved within 72 hours of the operation. The cat was weight-bearing on the limb 48 hours after surgery and sutures were removed after 14 days.

The caudal superficial epigastric axial pattern flap is a highly versatile pedicle flap suitable for closure of major skin defects over the caudal abdomen, the flank and the hind limb and has been well described for use as a single flap. Mayhew and Holt (2003) reported the use of simultaneous bilateral caudal superficial epigastric axial pattern flaps in the dog for an extensive caudal flank and thigh wound but primary closure of the donor site was difficult and required the use of skin expanders.

This is the first report of the use of simultaneous bilateral caudal superficial epigastric axial pattern flaps in the cat to close an extensive circumferential hind limb wound, and demonstrates that, unlike in the dog, donor sites can be closed easily.

Reference:

Mayhew, P.D. and Holt, D. E. (2003) JSAP 44, 534-538

10 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Biomechanical evaluation of different numbers, sizes and placement configurations of ligaclips required to secure cellophane bands.

Aidan B. McAlinden, MVB, cert SAS, Conor T. Buckley, BA, BAI, PhD and Barbara M. Kirby, DVM, MS, Diplomate ACVS, Diplomate ECVS

Objective:

To determine the optimal way to secure cellophane bands using ligaclips.

Study Design: In vitro mechanical evaluation. Sample Population: Single-layer and triple-layer cellophane bands, 9.0mm and 11.5mm ligaclips.

Methods: Triple-layer bands were secured with a different number (1-5), size (9.0 or 11.5mm) or configuration (linear or alternating placement) of ligaclips and mechanically tested. Ultimate load was measured in Newtons (N). Ultimate load for single-layer and triple- layer bands secured with four alternating 11.5mm ligaclips were compared. Descriptive statistics were reported as mean  SD with P<0.05 considered significant.

Results: Ultimate load was directly proportional to the number of ligaclips applied for the linear configuration, but not for the alternating configuration, which began to plateau after application of the fourth clip. Ultimate load for 11.5mm ligaclips was significantly higher compared to the corresponding number of 9.0mm ligaclips for both configurations (P<0.05). The ultimate load for ligaclips applied in an alternating configuration was significantly greater than those applied in a linear configuration for both sizes (P<0.05 and P<0.01 for the 9.0mm and 11.5mm ligaclips respectively). Ultimate load for four alternating 11.5 mm ligaclips applied to triple-layer cellophane bands was significantly greater than the same configuration applied to single-layer cellophane bands (P<0.01).

Conclusion: Triple-layer cellophane is recommended with an alternating configuration of four 11.5 mm ligaclips.

Clinical Relevance: Surgeons should be aware that the number, size and configuration of ligaclips and cellophane thickness should be considered to ensure optimal security of cellophane bands and prevent slippage.

11 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” VACUUM ASSISTED WOUND CLOSURE: A NEW TOOL IN THE MANAGEMENT OF TROUBLESOME WOUNDS

Gary W. Ellison, DVM, MS, Diplomate ACVS

University of Florida, College of Veterinary Medicine, Gainesville, FL

[email protected]

ABSTRACT

Vacuum-assisted wound closure (VAC) is a non-invasive, active, wound management therapy exposing the wound bed to local sub-atmospheric negative pressure through a closed system in order to facilitate wound healing. Initially introduced in human medicine for the treatment of chronic wounds, VAC removes fluid from the extra vascular space, improving circulation and enhancing the proliferation of granulation tissue.

A VAC system consists of several elements. Sterile polyurethane open-cell foam is cut to conform to the surface of the wound. The foam is placed within the wound making sure the foam is in contact with the entire wound surface. An egress tube runs from within the foam to another tube, which is connected to a reservoir and a vacuum pump. A plastic sheet with adhesive on one side is placed over the sponge and around the tubing creating an airtight seal with the skin around the wound margin. Sub-atmospheric pressure then applies a controlled suction force uniformly to all tissues on the surface of the wound.

Beneficial effects on wound healing have been documented in several animal models. Reported benefits include increases in tissue blood flow, granulation tissue formation and skin flap survival when compared to conventional bandaging techniques. VAC wound dressings also demonstrate a significant increase in the rate of bacterial clearance in experimentally infected.

The vacuum-assisted wound closure device and methodology are subject to United States and foreign patents. A worldwide license for VAC has been assigned to Kinetic Concepts, Inc. (KCI), San Antonio, TX. The VAC is a trademark of Kinetic Concepts, Inc.

APPLICABLE HUMAN LITERARY REVIEW

Non-Healing Wounds Vacuum-assisted closure was initially developed for the non-surgical treatment of chronic non-healing wounds in human patients. Of 175 patients with decubital ulcers treated with VAC therapy 171 responded favourably resulting in complete closure or closure following a less invasive skin graft or skin flap. In a study comparing VAC versus traditional wet-to-dry bandages for the treatment of 36 chronic non-healing wounds, VAC treated wounds decreased in size by 78% compared to a 30% size reduction in wounds treated with wet-to- dry bandages.

12 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Surgical Dehiscence Vacuum-assisted closure has been used extensively in human surgery for the closure of surgical dehiscence. The use of VAC therapy has been shown to decrease the wound management time required before a delayed secondary closure could be performed. The human literature also supports the use of VAC therapy in cases of surgical dehiscence with exposed orthopaedic hardware, bone or tendons. The VAC system maintains these wounds in a closed environment and enhances the rate of granulation tissue formation over exposed bone, tendon or orthopaedic implant.

Skin Avulsions Increased survival of skin flaps and skin avulsions injuries have been reported in both human patients as well as various animal models. In veterinary patients, these injuries can be difficult to manage since any attempt to stabilize the orthopaedic injuries often results in further vascular compromise of skin, which is relying primarily on the sub-dermal plexus for survival. The increased anatomic dead space and avascular tissue created by these physiologic degloving injuries also create a favourable environment for bacterial growth.

Prevention of Post-Operative Swelling and Seroma Formation In human surgical wounds associated with a high risk of seroma formation or post-operative weeping, VAC dressings placed over the surgical incision at a low negative pressure (50 mm Hg) have resulted in the prevention of seroma formation and the successful transition to a dry wound that healed uneventfully with one 24-hour application.

Abdominal and Thoracic Uses The VAC system has been used in human thoraces for the treatment of surgical dehiscence following median sternotomy and abdominal cavities after damage control laparotomy and for the treatment of abdominal compartment syndrome. Separation of the open celled foam from the abdominal and thoracic viscera was performed in some cases with fenestrated sheets of silicon. Enterocutaneous fistula formation has been reported as a result of foam eroding through the serosal surface of the intestines. These enterocutaneous fistulas were treated non-surgically with VAC using a series of progressively smaller foam pieces with finer pore sized until the fistulous tracts were sealed and healed by second intention.

APPLICATIONS IN VETERINARY MEDICINE

Vacuum-assisted closure was first utilized at the University of Florida Veterinary Medical Center in 2001 for the management of severe, traumatic degloving wounds in a tiger cub. Since that time, we have utilized VAC extensively in the treatment of acute and chronic wounds in dogs and cats. Initially, we used VAC in cases in which traditional bandaging and wound management techniques had failed. As we gained confidence in the technique, VAC became the initial treatment of choice for many wound conditions. We have found VAC invaluable for the management of traumatic wounds prior to definitive closure or preparation for skin grafting and in treatment of surgical dehiscence. We have also used VAC for the

13 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” treatment of chronic, problematic wounds and in the prevention of post-operative seroma formation following orthopaedic procedures.

Traumatic Skin Wounds and Avulsions

We have used VAC to treat a variety of skin avulsions and physiologic degloving injuries, many associated with severe musculoskeletal trauma. These injuries can be difficult to manage in dogs and cats because any attempt to stabilize the orthopaedic injuries often results in further vascular compromise of skin that is relying primarily on the sub-dermal plexus for survival. The increased anatomic dead space and avascular tissue created by physiologic degloving injuries also create a favourable environment for bacterial growth.

In cases were skin avulsion was associated with an open wound, the foam portion of the VAC bandage was placed between the skin and subcutaneous tissues for approximately 3 days until healthy granulation tissue began to form. The foam was then withdrawn from beneath the wound margin and placed over the remaining open wound surface to aid in adherence of the avulsed skin to the underlying granulation bed. In several cases, physiologic degloving occurred without an associated open wound. The skin in the avulsed area was fenestrated and a VAC bandage applied over the fenestrated area. Skin adherence to the underlying tissues occurred in most cases 3 to 4 days after initiation of VAC therapy.

Abdominal and thoracic uses We have used VAC for the treatment of septic peritonitis secondary to a dislodged PEG tube in a diabetic dog. Following exploratory laparotomy and thorough lavage, a sterile fenestrated sheet of plastic was sutured to each edge of the incised linea alba. Foam was then placed within the abdominal incision and covered with the adhesive dressing. The VAC bandage allowed the abdomen to remain open to aid in drainage while the airtight bandage minimized the risk of potential secondary nosocomial infections. A fenestrated drain was also placed within the dorsal abdominal cavity which allowed for intermittent abdominal lavage. This dog was euthanized 2 days post-operatively due to continued deterioration of a highly resistant Candida infection, however the techniques learned from treating an open abdominal wound with VAC may be beneficial in future cases of peritonitis.

We utilized VAC therapy over an open thoracic cavity in a dog presenting with penetrating bite wounds to the lateral chest and abdomen. The wounds had been closed primarily three days prior, following which the dog had developed signs of septicemia. Exploration of the wounds revealed a large defect and associated rib fractures with substantial necrosis and contamination of the intercostals musculature, as well as pyothorax. The thoracic and abdominal cavities were thoroughly lavaged and necrotic tissue debrided. The ribs were apposed, while intentionally leaving an incomplete seal of the thoracic cavity. Foam was then placed over the ribs and beneath the surrounding skin and the remaining VAC system applied routinely. The VAC was set at -125 mmHg and functioned not only to provide continuous suction to the wound, but to also drain the thoracic cavity. A thoracostomy tube was also placed to ensure a reliable method of thoracic drainage, however was not needed and was removed 48 hours after placement. The bandage was removed 3 days later and a significant amount of granulation tissue was present. The wound was closed at this point and the dog made a complete recovery.

14 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Complications and Contraindications

Few complications exist in the human literature regarding VAC therapy. The most common is mild skin irritation from contact with the foam. The manufacturer has proposed several contraindications to VAC therapy. Though the VAC system will debride wounds to some extent, it will not remove grossly necrotic or devitalized tissue and should not be used in place of proper surgical debridement. The VAC system should not be used in wounds associated with known malignancies, since the application of the VAC bandage will likely increase blood flow and stimulate cellular proliferation within the wound bed. The treatment of osteomyelitis with the VAC system alone is also contraindicated. Though VAC can be used over infected bone, resolution of osteomyelitis may be dependent on sequestrectomy where indicated and appropriate antibiotic therapy as well. Finally, care should be taken when placing VAC dressings near exposed arteries and veins. It is possible for the foam to erode through vasculature resulting in extensive blood loss. Similarly, VAC dressings should be used with caution in patients with coagulation abnormalities or patients with active bleeding.

Addendum: Equipment and application of Vacuum assisted wound dressings in veterinary medicine

It is essential that basic wound care principles be applied to all wounds prior to the application of VAC therapy. Proper debridement of devitalized tissues is essential for successful would closure and to eliminate any potential nidus for bacterial growth. Inability to thoroughly debride wounds prior to the application of VAC may result in the proliferation of granulation tissue over necrotic tissues resulting in delayed wound healing and abscess formation.

A VAC system has several essential elements. Sterile open cell polyurethane foam, plastic egress tubes, collection reservoirs and an adjustable suction pump capable of intermittent or continuous negatives pressures ranging from –50 mm Hg to –200 mm Hg are all available though Kinetic Concepts Inc.

The open cell polyurethane foam is used for the application. Each foam dressing comes in a sterile package with two transparent plastic self-adhesive sheets. The foam can be cut to conform to the shape of the wound. The foam should be placed within the wound so that it is in contact with the entire wound surface especially the deep margins of the wound. Foam should be placed within the wound fully expanded and care should be taken to avoid tightly packing foam into wounds. Foam bandages available through KCI are often too large for dogs and cats. The foam can be cut to shape and excess foam utilized in future VAC bandages.

A plastic fenestrated egress tube is inserted into a hole cut into the foam or placed between 2 pieces of foam. Placement of the tube fenestrations directly on the wound should be avoided as this may cause pressure necrosis in tissues around the fenestration sites and result in clogging of the vacuum system. Once the foam and plastic tubing are in place the two are then covered with an adhesive plastic sheet that extends several centimetres beyond the wound margins. In veterinary patients it is helpful to cleanly shave all hair surrounding the wound in order to facilitate adherence of the plastic sheet and establish an airtight seal. In areas with difficult bandage conformation, we have also found it helpful to 15 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” apply stoma paste to the skin around the wound to aid in adherence of the skin to the plastic adhesive sheet. It is essential that an airtight sealed be established in order to maintain constant negative pressure and prevent desiccation of the underlying tissues. The egress suction tube is then attached to a collection reservoir and to the vacuum pump. When the bandage is properly placed, a closed system is created consisting of the wound, foam, suction tube, collection reservoir and suction pump.

A continuous negative pressure setting of 125 mm Hg is most commonly used. Initial animal studies showed improved blood flow and granulation tissue formation with intermittent suction, however, when intermittent suction was performed in the clinical setting on human patients, increased wound discomfort was noted. For weeping wounds and postoperative prevention of seroma and oedema formation, a lower negative pressure setting of 50 mm Hg is used.

The frequency of VAC bandage changes depends on the characteristics of the individual wound. Vacuum-assisted closure bandage dressings are typically changed every 2 to 3 days. If VAC bandages are left in place over 4 to 5 days, granulation tissue may grow into the open cell foam requiring surgical removal of the foam bandage. In veterinary patients, bandage changes can often be performed under heavy sedation. If extended VAC therapy is to be performed, the foam can be cut out through the plastic adhesive sheets while leaving the portion of the sheet adhered to the skin in place. New adhesive sheets are placed over the previously applied bandage to avoid pulling the adhesive sheet away from the skin.

16 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” LAPAROSCOPY ABDOMINAL EXPLORATION

Eric Monnet, DVM, Ph.D., FAHA Diplomate ACVS,ECVS Colorado State University, Fort Collins, Colorado

Laparoscopy is a minimally invasive technique for viewing the internal structures of the abdominal cavity. The abdominal cavity is first distended with gas and then a rigid telescope (laparoscope) is placed through a portal that has been positioned through the abdominal wall to examine the contents of the peritoneal cavity. With the telescope in place, either biopsy forceps or an assortment of surgical instruments can then also be introduced into the abdomen through adjacent portals to perform various diagnostic or surgical procedures.

The minimal invasiveness of the procedure, diagnostic accuracy and rapid patient recovery make laparoscopy often a preferred technique over other more invasive procedures. Small animal laparoscopy initially evolved as a diagnostic tool but has progressed to where there is now ever-increasing interest in the application of minimally invasive laparoscopic surgical procedures.

INDICATIONS AND CONTRAINDICATIONS Table 1. Basic Laparoscopic Techniques Diagnostic Common indications for laparoscopy are to examine Liver biopsy and biopsy the abdominal organs or masses or to Cholecystocentesis perform surgical procedures. Laparoscopy may not Pancreatic biopsy however always replace a complete abdominal Kidney biopsy exploratory but provides a minimally invasive means of Intestinal biopsy Adrenal evaluation accomplishing a number of diagnostic and surgical Splenic evaluation procedures currently used in small animals (Table 1). Reproductive evaluation This list of indications has been evolving over time as Surgical we learn more of the potentials of laparoscopy as a Feeding tube placement diagnostics tool and as a means of minimally invasive Gastropexy surgery. Ovariohysterectomy Cryptorchid surgery Gastric foreign body removal Diagnostic laparoscopy is commonly used as a Cystoscopy method for obtaining liver, pancreas, kidney, splenic and intestinal biopsies. It is generally accepted that laparoscopy provides better 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. Full thickness intestinal biopsies can also be performed using laparoscopic assistance. Other ancillary diagnostic techniques include reproductive evaluation of the ovaries and uterus with the capability for direct intrauterine insemination, gallbladder aspiration, splenic pulp pressure measurements, laparoscopic directed splenoportography and urinary bladder evaluation. Common surgical techniques currently being performed in small animals include cryptorchid

17 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” surgery, ovariohysterectomy, and prophylactic gastropexy. Other laparoscopic procedures performed are cystoscopy, jejunostomy or gastrostomy feeding tube placement, abdominal lavage tube placement, gastric foreign body removal and adrenalectomy. The potential for laparoscopic surgery in veterinary medicine is limited only by our innovation and surgical instrumentation available.

The many advantages of surgical laparoscopy over a conventional open surgical exploratory laparotomy include improved patient recovery because of smaller surgical sites, lower postoperative morbidity, infection rate and postoperative pain.

There are few if any contraindications of laparoscopy because of the minimal invasiveness of the procedure. Often the patients that are a high risk for surgical exploratory actually may become good candidates for a less invasive laparoscopic procedure. Ascites, abnormal clotting times and poor patient condition are only relative contraindications. Ascitic fluid can be removed prior to or during the procedure and has little influence over the probability of success of the laparoscopy. Clinical experience suggests that abnormal clotting times may not completely preclude performing laparoscopy. Absolute contraindications for laparoscopy include septic peritonitis or conditions when obvious conventional surgical intervention is indicated. Relative contraindications include the patient condition, small body size or obesity. Patients that are either a poor anaesthetic or surgical risk would obviously preclude performing the procedure. We have performed laparoscopy on severely debilitated patients using only local anaesthesia and sedation in which general anaesthesia and surgical laparotomy were considered to be too risky to the patient. The procedure also becomes difficult in the very small patient (<2 kg body weight) and in the very obese patient.

LAPAROSCOPIC EQUIPMENT

The basic equipment required for diagnostic laparoscopy includes the telescope, corresponding trocar-cannula units, light source, gas insufflator, Veress (insufflation) needle and various forceps and ancillary instruments (Table 2). Telescopes most frequently used in small animal laparoscopy generally range in diameters from 2.7 to 10 mm. The 5 mm diameter is adequate for most small animal procedures. The 0 degree designation means that the telescope views the visual field directly in front of the telescope in180 degree circumference. Angled viewing scopes, such as the most commonly used 30-degree Table 2 Basic Diagnostic Laparoscopic Equipment telescopes, view in a down ward direction - 5 mm telescope (0 degrees) 30 degrees from the telescope body. The - 2-cannulas angled telescopes enable the operator to - Veress needle - light source look over the top of organs and view in small - light cable areas however this angulation also makes - CO2 insufflator the orientation more difficult for the - palpation probe inexperienced operator. - oval biopsy forceps - punch biopsy forceps The telescope is next attached to a light - grasping forceps source using a light guide cable. It is - video camera and monitor optional - photo documentation generally recommended that a high-intensity light source such as xenon or halogen be used in laparoscopy especially if video or 18 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” photographic documentation is being incorporated. Xenon is considered to give the truest colours of the abdominal organs and is recommended.

The endoscopic video camera is attached to the telescope and allows the image to be viewed on a monitor rather than having to look directly through the telescope lens. Video assistance is essential when performing surgical laparoscopy but not for simple diagnostic techniques. Video guidance does however make laparoscopy much easier to learn and perform and is recommended by the authors. A Veress needle is used for initial insufflation of the abdominal cavity. The needle consists of an outer sharp cutting tip and 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 the needle enters the abdominal cavity. 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 and function to dispense gas at a prescribed rate while maintaining a predetermined intra-abdominal pressure. Carbon dioxide is the gas of choice for insufflation because of the safety in preventing air emboli and spark ignition during cauterization.

Following insufflation telescope and instruments are then placed through the abdominal cavity using a trocar cannula unit that is of a corresponding size to receive either the telescope or instruments. The trocar is a sharp pointed instrument and when housed in the cannula is used to penetrate abdominal muscles and peritoneum. Once the trocar is removed the cannula remains in place traversing the abdominal wall and becomes a portal for introduction of the telescope or instruments into the abdominal cavity.

To perform diagnostic laparoscopy a number of accessory instruments are essential. They are placed through a second cannula unit. A palpation probe is required to move and palpate abdominal organs.

For diagnostic laparoscopy at least one biopsy forceps is essential. We find the 5 mm diameter biopsy forceps with oval biopsy cups to be the most versatile and commonly used for the liver, spleen, abdominal mass, and lymph node biopsy. A second biopsy instrument is the punch type biopsy forceps and is often preferred by some for pancreatic biopsies. Core biopsy needles and aspiration needles are also necessary for diagnostic laparoscopy. One can also use long spinal needles for aspiration. A “true-cut” type biopsy needle is required for both kidney and for deep tissue biopsies. Surgical laparoscopy often requires a vast array of instruments designed for specific indications. Common instruments include scissors, grasping forceps, and aspiration tubes and clip applicators. For surgical laparoscopy in small animals 5 mm diameter instruments are commonly used however certain specialized instruments such as stapling devices are generally 10 mm or larger in diameter. Many of the biopsy and surgical instruments also have capabilities for monopolar electrosurgery at their distal tip.

LAPAROSCOPIC TECHNIQUE

The first step in laparoscopy is to establish a pneumoperitoneum before cannula placement. A small 2-mm skin incision is then made with a scalpel blade through the skin for placement of the Veress needle. The entry site placement is either adjacent to the cannula portal sites or in the same site to be used by the first telescope portal. The needle is then placed 19 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” through the abdominal wall by grasping the outer hub of the needle, so that the inner blunt obturator is free to move into the needle as it passes through the abdominal wall. The blunt obturator will then to spring into place once the peritoneum has been penetrated. One should always assure that the Veress needle is in the abdominal cavity and is not retained in the muscle planes of the abdominal wall or under the peritoneum. Inadvertent insufflation in the subcutaneous tissues with CO2 makes the procedure almost impossible to continue.

To assure that the Veress needle is through the abdominal wall and in the abdominal cavity one should both palpate with the needle tip on the inner surface of abdominal wall and by using what is referred to as the “hanging drop test”. This test involves placing a drop of saline in the hub of the Veress needle and then by lifting the abdominal wall with the needle shaft the negative pressure within the abdominal cavity will pull the drop of saline into the needle. This then assures that the needle is in the correct location and not resting into an organ, abdominal wall or mass. Insufflation of gas into a mass, organ or vessel can result in fatal air emboli. It is also important that the needle tip is also not placed deep within the abdominal cavity. If the needle tip lies under the omentum during insufflation with gas the omentum will balloon up and subsequently will obscure visualization when the telescope is placed in the abdomen.

Next the insufflation line is attached to the Veress needle and the automatic insufflator is turned on and the flow rate is set. When the abdomen is distended with CO2 it will become tympanic upon palpation. The abdominal pressure should be no greater than 15 mmHg. In most all cases 10 mmHg is adequate to maintain abdominal distention and perform laparoscopy in small animals. Intraabdominal pressures are shown on most all automatic insufflators. Care should be taken not to over distend the abdomen with gas that will impair abdominal venous return and excursions of the diaphragm.

A cannula unit that will receive the telescope is then placed through the abdominal wall. First an incision is made through the skin large enough to accommodate the diameter cannula. To assure the skin incision is the correct diameter one may make an imprint of the cannula tip on the skin that can then be used as a template for the incision length. A complete incision through all skin layers down to the subcutaneous tissues is required or it will be very difficult to penetrate the abdominal wall. A hemostat can be used to open the wound, assure the skin incision is the correct diameter and that it extends through all cutaneous and subcutaneous tissues.

The trocar-cannula unit is then held with the trocar head firmly against the palm of the hand to prevent the trocar from sliding back into the cannula as it is passes through the abdominal wall. With the abdominal cavity adequately insufflated the tip of the trocar-cannula is placed in the incision and using a twisting and thrusting motion the trocar is passed through the abdominal wall. Immediately after abdominal entry the sharp trocar is removed from the cannula to prevent possible organ trauma. The cannula can then be advanced deeper into the abdomen. The Veress needle is then removed and the C02 line attached to the insufflation stopcock of the telescope cannula.

Following the initial cannula placement the telescope is prepared for entry into the abdomen. We recommend to first place the telescope in either a pan of warm sterile water or saline to bring it to body temperature thus reducing the incidence of lens fogging when the telescope enters the abdominal cavity. One should then assure the telescope lens is clean by wiping 20 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” the lens with a saline-soaked gauze sponge. The light cable is then attached to the telescope and the light guide cable is handed to the assistant for attachment to the light source. When using a video camera, the camera head is next attached to the telescope. The light source, camera and monitor can now be turned on. The telescope is now advanced through the cannula and into the abdomen.

With the telescope in the abdominal cavity, careful examination of the contents is then performed. The site of entry for the second (accessory) portal is then selected. This location is determined by the ancillary procedures that are to be performed. It is important that the secondary cannula be placed far enough away from the telescope so that manipulation of instruments is not hindered by the close proximity of the telescope and second cannula. If an operator is right handed the operating cannula is generally placed to the right of the telescope. When using both 5 mm telescope and accessory instruments it is possible to switch telescope and instruments from one cannula to the other.

Abdominal exploration is begun using the palpation probe to “feel” and move the organs as needed. A 5mm palpation probe with one-centimetre markings along the shaft is passed through the secondary trocar cannula. As 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 and manipulated until they come into view. This technique often results into serious tissue trauma. All accessory instruments are passed into the abdomen using the same technique.

At the conclusion of the laparoscopic procedure the instruments and telescope are removed.

The pneumoperitoneum is removed by opening the cannula valves and permitting the CO2 to escape. The cannulas 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 anaesthesia in the trocar cannula sites and prescribe systemic analgesia for 12-24 hours following the procedure.

COMPLICATIONS OF LAPAROSCOPY

The complication rate of laparoscopy is low. Table 3. Potential Laparoscopic Complication Potential complications are listed in table 3. Anaesthesia related Serious complications include anaesthetic or Veress needle/trocar insertion cardiovascular related death, bleeding, or air Injury to abdominal wall embolism. Penetration of organs Perforation of hollow viscus Complications resulting from either Veress Insufflation needle placement or trocar insertion include Subcutaneous emphysema injury to vessels in the abdominal wall, Peritoneal tenting Inappropriate insufflation penetration of organs or perforation of a Pneumothorax hollow viscus. Careful attention to technique Gas embolism minimizes these concerns. Operative complications Bleeding Complications also may occur during the Tissue injury insufflation process. That includes Technical problems subcutaneous emphysema if the Veress Lack of experience needle is not through the abdominal wall or Equipment related problems peritoneal tenting if the needle lies under

21 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” omentum during insufflation. With inappropriate insufflation one is unable to visualize the abdominal cavity adequately making the procedure much more difficult than necessary. Serious complications associated with insufflation would be gas embolism in or pneumothorax. Gas embolism was reported during insufflation in a dog when the Veress needle was inserted in the spleen. A pneumothorax will occur either from accidental penetration of the diaphragm or from a diaphragmatic hernia. Minor complications are generally operative associated resulting from one being unfamiliar with the technique, the limitation and potential complications of a procedure or equipment. Complications of surgical laparoscopy would be expected to be greater but thought to be similar to the complications occurring with open surgical procedure. Cardiovascular and respiratory complications can result from the positioning of the patient during ovariohysterectomy for example. The abdominal organs compressing the diaphragm will limit it’s the excursions. Utilization of a ventilator is required during such procedure to prevent these complications.

SUMMARY

Laparoscopy is a minimally invasive technique for diagnostic and surgical procedures. Once the basic technique of laparoscopy is mastered and the appropriate indications are applied to the procedures it becomes a simple and rewarding addition to small animal veterinary medicine and surgery. As our ability advances newer diagnostic and therapeutic procedures will no doubt be developed.

22 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” SURGICAL TRENDS IN THE OBSTRUCTIVE JAUNDICE PATIENT

Steve J.Mehler, DVM, Diplomate ACVS

Surgical diseases of the extrahepatic biliary tract in small animals are not uncommon. As we are evolving into better diagnosticians and clinicians, we, as a profession are recognizing the clinical signs of EBT disease more frequently and earlier than ever before. This accompanied with technological advances in diagnostic and therapeutic modalities has provided us with a unique opportunity to greatly impact the outcome of our patients with EBT disease. However, a review of the recent veterinary literature provides a bleak insight to the overall outcome of dogs and cats undergoing surgery for diseases of the extrahepatic biliary tract. When study numbers are combined the overall survival rate for dogs is roughly (140/220) 63.6% and for cats ~ (28/68) 41%. These numbers are appalling and should provide a great impetus for us as scientists to ask, “why?”.

The assumption that surgery of the extrahepatic biliary tract (EBT) alone is the culprit behind the high mortality rates continues to plague our profession. This thought process is contributing to a worsening trend in outcome for our patients with EBT disease. A better understanding of the normal physiology of the EBT and the pathophysiology of diseases of the EBT accompanied by a more aggressive diagnostic and therapeutic approach to patients with EBT disease may play a role in providing a better long term outcome for our patients inflicted with diseases of the EBT. The common use of cholecystectomy to treat human patients with non-obstructive cholelithiasis has significantly driven down the morbidity and mortality rates in humans undergoing EBT surgery. Although veterinary medicine is lacking in scientific evidence that a paradigm shift in how these patients should be dealt with, it is likely that performing definitive surgical procedures early in the course of certain EBT disease will provide a better long term outcome for our patients. When the data from dogs with EBT obstruction are evaluated, there is a trend towards a linear correlation between onset of clinical signs to surgery and outcome.

The poor outcome of small animal patients with EBT disease has led us as clinicians to seek out other therapeutic avenues to treat these patients without pursuing surgery. A recent collection of publications involving a small number of cases of patients with EBT obstruction have provided some alternative techniques to surgery and mostly involve draining of the bile via intermittent or continuous or cholecystocentesis until the cause of the obstruction has resolved or until the patient is more stable for surgery. On a physiologic level, this does decompress the liver; however, a major component of these patients’ systemic alterations is due to the absence of bile within the small intestine. Although still controversial, more recent human literature agrees that removing bile from the system, preoperative biliary decompression, and many medical attempts at avoiding surgery for EBT disease has led to prolonged hospitalization, increased morbidity, and in some instances, increases in mortality. Granted, dogs and cats are not people and veterinary medicine is lacking in clinical evidence that suggests one method over another, it would appear that early surgical intervention may provide at least part of the solution to this long standing problem. 23 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” Frequently used surgical techniques for patients with EBT disease include; cholecystotomy, cholecystectomy, choledochal stenting via duodenotomy, and cholecystoenteric anastamosis. This abstract briefly reviews some less invasive approaches to EBT disease.

Choledochotomy

Choledochotomy and primary repair of extrahepatic biliary duct tears have been described, but long-term outcome has not been extensively investigated. Described complications include incisional leakage and subsequent bile peritonitis, stricture, and adhesion formation. These surgical techniques are presented as alternatives or adjunct procedures which can be considered as reasonable options.

Recently, Seven dogs and three cats with confirmed extrahepatic biliary tract obstruction (EHBTO) were reported in abstract form to have had choledochotomies performed for a variety of diseases. All dogs and cats were discharged from the hospital, and did not have clinical recurrence of EHBTO.

Choledochotomy and primary repair of common bile duct tears are feasible surgical options which should be considered if indicated for use alone or in conjunction with other procedures when performing surgery to address EHBTO.

Percutaneous interventions (Minimally invasive versus minimalistic)

Percutaneous transhepatic cholecystocentesis and cholecystostomy tube placement have been described in veterinary medicine in patients with EBT disease. These techniques are used for both diagnostic and temporarily therapeutic alternatives to surgical sample collection and definitive intervention. A major source of systemic illness in patient s with EBT obstruction is the lack of bile salts in the small intestine. Simply put, bile salts not only play an intricate role in fat and fat soluble vitamin absorption but also act as intestinal detergents that bind bacteria and endotoxin. The lack of bile salts in the small intestine lead to fat malabsorption, bacteremia and endotoxemia with secondary alterations in primary and secondary hemostasis, renal dysfunction, decreased myocardial contractility, and depressed activity of the reticuloendothelial system. Although percutaneous decompression of the EBT allows for drainage of the intrahepatic biliary tract and decreases the backup unconjugated and conjugated bilirubin in the serum it does not address the lack of bile slats in the small intestine.

Percutaneous bile duct access and stenting

Access to the bile duct from this approach is not easy in dogs and involves sequential dilation of the skin, body wall, liver parenchyma, and gall bladder wall to allow for access to the bile duct and possibly the duodenum for stenting.

To avoid making a large hole in the liver or gallbladder, a small catheter and guidewire can be used to gain access to the bile duct via percutaneous transhepatic gallbladder access. The long wire is carefully guided into the duodenum and then grabbed by endoscopic forceps within the proximal duodenum and pulled out of the mouth. The other end of the wire is maintained outside of the patient. A stent can then be placed over the wire, down the mouth, and across the major duodenal papilla as needed.

24 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” These techniques allow for decompression of the biliary tract and re-establish antegrade flow of bile into the small intestine and are indicated in patients with EBT obstruction secondary to pancreatitis and some tumours.

Endoscopic Retrograde Access (ERA)/Endoscopic Retrograde Cholangiopancreatrography (ERCP)

Using a sideview flexible endoscope, retrograde access to the EBT becomes less challenging. Using this specialized flexible endoscope, bile can be collected, positive contrast studies of the EBT can be performed, and stents can be placed across the major duodenal papilla. This technique is known to cause varying degrees of pancreatitis in humans and dogs.

Rigid Endoscopic Retrograde Access (Lap Assisted Retrograde Access)

Using rigid endoscopic techniques, the distal duodenum is identified and exteriorized out of the abdomen through a small incision in the skin and body wall. A 5mm cannula is placed in the distal duodenum and directed orad. A 5mm rigid scope is then used to identify the major duodenal papilla and wire access is achieved. Again, this technique can be used to collect samples of bile, perform positive contrast studies, and place stents across the major duodenal papilla. The major benefit of this technique is that biopsies of the pancreas, liver, and full thickness bowel can be collected before or after biliary tract interventions.

Laparoscopic Cholecystectomy

In humans, laparoscopic cholecystectomy has been performed since the early 1980s and represents the treatment of choice for gallstone disease and acute cholecystitis. Approximately 75% of all human cholecystectomies are performed laparoscopically and often on an outpatient basis. Operative safety is considered very high and conversion to open surgery occurs in only 5–10% of cases. Laparoscopic cholecystectomy is useful in our patients but at this time, patient selection remains the most important factor for success. Patients with subclinical or mild clinical disease of nonruptured gallbladder mucocele and without evidence of EBT obstruction are good candidates for this procedure. Also, the cat or dog with nonclinical or intermittent signs associated with nonobstructive cholelithiasis may prove to be good candidates for laparoscopic cholecystectomy.

References available upon request

25 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” LAPAROSCOPY

LIVER BIOPSY

Eric Monnet, DVM, PhD, FAHA, DACVS and ECVS

College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado

Laparoscopy is a minimally invasive technique for viewing the internal structures of the abdominal cavity. Laparoscopy is simple to perform and considered to be safe having very 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. Laparoscopic liver biopsy is considered by many to be a preferred method of obtaining a liver biopsy. Other diagnostic modalities often do not provide sufficient enough information on the liver. One is not only able to view the liver and but also 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 over 85% of the liver surface, take directed tissue biopsies and monitor for excessive bleeding. We recommend using a 5 mm oval cup biopsy forceps for the liver. A recent study emphasized the benefit of laparoscopic cup biopsies when two 18g needle biopsies were compared to the laparoscopic cup biopsies. Prior to liver biopsy the coagulation parameters are generally evaluated including a bleeding time. Although coagulopathies are a relative contraindication of liver biopsy the coagulation status does not necessarily predict if the patient will bleed from a liver biopsy. 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. It is always important to biopsy 3 to 4 areas of the liver including areas that appear normal as well as 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 pathology 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 bleed very little. If bleeding is considered to be excessive several steps should be taken. First, the palpation probe can be placed into the biopsy site and pressure applied over the area with the tip of the probe. Alternatively, a small piece of saline soaked Gel- Foam™ can be placed into the biopsy site using either laparoscopic grasping or biopsy forceps. These options are sufficient to control excessive bleeding.

26 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” The gallbladder and extrahepatic biliary ducts can be evaluated also during laparoscopy. Bile can be aspirated with a long spinal needle introduced through the abdominal wall. It is important to place the needle behind the attachment of the diaphragm because if he needle goes through the diaphragm it will induce a tension pneumothorax. The gallbladder is deflated is deflated as much as possible to minimize the risk of leakage in the abdominal cavity. Laparoscopy is a minimally invasive technique for diagnostic and surgical procedures. Once the basic technique of laparoscopy is mastered and the appropriate indications are applied to the procedures it becomes a simple and rewarding addition to small animal veterinary medicine and surgery. As our ability advances newer diagnostic and therapeutic procedures will no doubt be developed.

27 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” PORTOSYSTEMIC SHUNTS: WHY USE CELLOPHANE BANDING?

Portosystemic shunt (PSS) is an abnormal vessel that shunts portal blood from the splanchnic circulation to flow directly to the systemic circulation by passing the liver. Toxins, hormones, nutrients, escaping bacteria, and exogenous drugs also bypass the liver resulting in hepatic encephalopathy (HE). Hepatic growth and size are maintained by normal portal blood flow (80% of the total liver blood flow) and hepatotrophic hormones (insulin, glucagon). Diversion of portal blood flow results in atrophy of the liver inducing further deterioration of liver function. Dogs or cats with congenital portosystemic shunt present with multiple clinical signs related to HE. Differentiation between single congenital and multiple acquired shunts is important, as their treatment and prognosis differ greatly. Treatment of choice for congenital shunt is partial or complete surgical ligation of the anomalous vessel; this may result in fatal portal hypertension in patients with acquired shunt. Portal hypertension secondary to primary liver disease (i.e. hepatic cirrhosis) result generally in the development of acquired shunts. Congenital portosystemic shunts may be classified as single or multiple and intrahepatic or extrahepatic. Five types of PSS have been described. Eighty percent of the PSS are single, 72% are extrahepatic, and 95% are between the portal vein and the caudal vena cava. Surgery is recognized as the treatment of choice for PSS. Because liver needs hepatotrophic substances from portal blood flow, deterioration of liver function can be expected if the shunted blood flow is not surgically corrected in a physiologic direction. Medical treatment will not correct this alteration, therefore long term survival is not expected. In one study, only 2 of 8 dogs with medical treatment were still alive at 6 months. Life expectancy of 2 months to 2 years is generally reported; the actual time presumably being dependent on the amount of portal blood flow. Restoring the flow of hepatotrophic substances to sinusoidal milieu results in substantial hepatic regeneration and reversal of functional impairment. Patients with PSS experience a reduction in absorption, metabolism, and clearance of drugs due to liver impairment. Fentanyl can be used for sedation. Mask induction with isoflurane followed by endotracheal intubation is the method of choice. Dextrose (2.5%) is important during surgery and the immediate postoperative period to maintain blood glucose. Cephalosporin perioperatively is recommended. Ischemic episode can occur in the bowel during manipulation of the PSS that may result in bacterial embolization. A standard ventral midline coeliotomy is performed from the xiphoid to pubis to explore the portal system. The portal vein and caudal vena cava are located by retracting the duodenum medially. The portal vein is identified ventral to the caudal vena cava at the most dorsal aspect of the mesoduodenum. The caudal vena cava is examined for identification of any abnormal blood vessels. Normally, from the renal and phrenicoabdominal veins to the hilus of the liver there should be no blood vessels entering the caudal vena cava ventrally. Any 28 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” blood vessel in this area should be suspect as an extrahepatic shunting blood vessel. Turbulence in this portion of the vena cava is another important clue for locating a possible shunt. If nothing abnormal is noticed the left omental bursa is entered and all tributaries from the portal vein are identified. Most often, shunting vessels come from the gastrosplenic vein in dogs and left gastric vein in cats. If no shunting vessel can be located, investigation for an intrahepatic shunt is started. Inspection of the hepatic veins cranial to the liver and inspection of liver lobes for dilation are the first steps in identification of an intrahepatic shunt. Complete occlusion of the shunt at the time of surgery is associated with a better prognosis. However, complete occlusion may not be possible at the time of surgery because the liver parenchyma cannot accommodate the augmentation in blood flow. It then results in portal hypertension. Occlusion of a PSS has been performed traditionally with a suture placed around the shunt and tight while the portal pressure was measured. This technique resulted in acute or chronic portal hypertension in 15 to 20 % of the cases. Acute portal hypertension resulted in death in most of the cases. Chronic portal hypertension induced ascites and the opening of acquired shunts. To palliate to these problems and achieve complete occlusion of the PSS gradual occlusion has been performed with ameroid constrictor or cellophane band. Both of these devices induce a slow and complete occlusion of the PSS over 4 to 8 weeks. The liver parenchyma can then accommodate the augmentation in blood flow without inducing portal hypertension. A strip of cellophane 1 cm wide is folded three times on itself. It is then placed around the shunt vessels without inducing any occlusion of the shunt. The cellophane is stabilized with a vascular clip. There is no need to partially occlude the shunt vessel to a diameter less than 3 mm. Partial occlusion might even be detrimental for the patient in the long term. Cellophane band is light and can be placed like a suture. It does not require an extensive dissection around the shunt to be placed. Since it is light, there is no risk to induce an acute complete occlusion of the shunt because of weight shifting. Postoperatively, patients are examined for signs of portal hypertension: sepsis, abdominal pain, bloody diarrhea, and ascites. If signs of portal hypertension occur, the patient is taken back to surgery and the suture released. Failure to remove the ligature will result in septic shock and death. Hypothermia during surgery and postoperatively should be corrected aggressively. Dextrose (2.5%) intravenously is maintained. Thrombosis of the portal vein has been reported as complication of a partial ligation of intrahepatic PSS. Postoperative seizures have been reported as a complication of ligation of PSS and they carry a poor prognosis. Seizures may occur immediately or up to 3 days postoperatively. Surgical mortality associated with treatment of PSS can be as high as 20 %. The intraoperative and immediate postoperative periods are most critical. Hypothermia and hypoglycemia should be anticipated and treated promptly. With the devices for gradual occlusion the incidence of complications seems significantly reduced. Post-operatively the animals should be maintained on a low protein diet, amoxicillin or neomycin, and lactulose. Bile acids should be monitored at one, three and six months after surgery. Lactulose should be interrupted one month after surgery. The antibiotics should then be removed from the treatment. Three months after surgery the diet can be progressively return to normal. If the animal is showing signs of hepatic encephalopathy then the low protein diet is re-instituted. 29 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” With cellophane bile acids do not come to within normal limits before 3 to 6 months after surgery. The cellophane is inducing a slow and progressive occlusion of the shunt. A slow progressive occlusion of the shunt seems to decrease the risk of developing acquired shunts like ameroid ring has been.

30 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” CYTOSCOPIC LASER ABLATION OF ECTOPIC URETERS (CLA)

Steve J.Mehler, DVM, Diplomate ACVS

Ectopic ureters are a common congenital anatomic deformity in dogs with the ureteral orifice being positioned distal to the bladder trigone within the ureter, vagina, vestibule or uterus. Ectopic ureters can create a significant dilemma as one considers various approaches to both diagnosis and treatment. Interventional radiologic and interventional endoscopic techniques have aided in the ability to simultaneously diagnosis treat ectopic ureters in a minimally invasive fashion.

Equipment needed includes flexible (7.5-8.2 French) and rigid (diameters range from 1.9 mm to 7.5 mm) endoscopes, different types of intracorporeal lasers are available for this procedure including Holmium:YAG and diode. A fluoroscopic C-arm is sufficient for visualization and ureteral intervention, and is useful for this procedure, but is not necessary. Various guidewires and catheters are also needed for each procedure. Ureteral stents in numerous shapes and sizes (double pigtail, locking loop pigtail, or nephroureteral stents) are soft polyurethane catheters that can be easily removed after resolution of ureteral disease. These stents are typically not needed for this procedure unless complications occur.

I prefer the use of a Holmium laser for this procedure. The holmium laser, being a long- pulsed laser, creates thermal interactions with tissue. This makes it useful for both laser lithotripsy and soft tissue ablation. The holmium laser has a wavelength of 2100 nm making the laser beam invisible. Anyone in the room while the laser is in use should wear appropriate laser safety eyewear specific to the wavelength of the laser, even if the procedure is being done endoscopically. The routine settings used for CLA by the author are:

Energy (Joule) 0.80

Rep. Rate (Hz) 10

Average Power (watts) 8

Fibre size (um) 400

Pulse width (us) 700

Under general anaesthesia, via cystoscopy and, if available, fluoroscopy, an angle-tipped hydrophilic guidewire (Weasel® wire, Infiniti Medical) is advanced retrograde into the ureterovesicular, ureterourethral, or ureterovaginal junction, up the distal ureter and curled into the renal pelvis or left in the proximal ureter. A ureteral catheter is then advanced over

31 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” the wire under fluoroscopic or cystoscopic guidance, and the guidewire is removed. A retrograde contrast ureteropyelogram can be performed, if needed, to help identify any lesions, filling defects, dilations, tortuosity of the ureter, ureter diameter, or other abnormalities in the ureter or renal pelvis. This is the typical approach for female and large male dogs. In small male dogs a combined retrograde and laparoscopic assisted antegrade approach can be used for visualization, diagnosis, and treatment.

Retrograde positive contrast ureterograms allow for adequate visualization of the ureters without the risk of extravasation of contrast in the retroperitoneal space (i.e., antegrade pyelography) and prevents the risk of contrast induced nephropathy or Ig mediated systemic reactions (EU or IVP), since the contrast agent remains in the renal collection system and is not injected intravascularly.

Once the ureteral catheter is in place, the laser fibre is pushed out of the tip of the instrument channel on the cystoscope. The aiming beam is turned on (green or red). The aiming beam is aimed at the area of interest, which is the most distal aspect of the abnormal ureter. The laser is only fired on top of the ureteral catheter so that the lower urinary tract wall is not penetrated. The most ventral aspect of the ureteral trough should be laser ablated from distal to proximal until the opening is within in the bladder neck. If the wall is penetrated it is possible to finish the CLA and recover the patient with a urinary catheter in place for a few days to allow the hole to heal. A contrast cystourethrogram or repeat cystoscopy should be performed before discharging the patient from the hospital. Ectopic ureters are a common congenital anatomic deformity in dogs with the ureteral orifice being positioned distal to the bladder trigone within the urethra, vagina, vestibule or uterus. Over 95% of dogs with ectopic ureters transverse intramurally and are candidates for this minimally invasive procedure. This procedure is often performed on an out-patient basis at the time of cystoscopic diagnosis, avoiding the need for more than one anaesthetic procedure for definitive therapy.

Overall, surgical fixation of intramural and extramural ectopic ureters reports results of continued incontinence with concurrent medical intervention in anywhere from 40-71% of cases. Endoscopic repair of ectopic ureters has been performed in over 50 dogs successfully at 4 institutions in the United States. Thus far, in the combined experience of the University of Pennsylvania and Michigan State University, continence has been maintained in 80% of patients and 100% of male dogs are reported to be immediately continent. If the University of Pennsylvania patients are evaluated alone, continence has been maintained in 87.5% of patients either with (25%) or without (62.5%) concurrent medications (Allyson Berent, pers com). This procedure is successful in both male and female dogs with intramural ureteral ectopia, avoiding laparotomy, cystotomy, urethrotomy and ureterotomy.

32 AVSTS Pre-BSAVA meeting 2009 “What’s New & Hot?” LAPAROSCOPY

CYSTOSCOPY

There are a number of minimally invasive surgical (MIS) procedures that are currently performed using laparoscopy. Many of these procedures require multiple trocar/cannula portals, specific minimally invasive surgical instruments, loop ligatures, clip applicators and monopolar electrosurgery.

Laparoscopic cystoscopy is an alternate method that allows placement of a laparoscopic telescope into the urinary bladder that has been exteriorized through the abdominal wall for examination, biopsy and calculi removal.

Prior to surgery, a urinary catheter is placed. The catheter is then connected to a bag of saline in a pressure bag. The technique involves a standard laparoscopic entry with the telescope placement on the abdominal midline caudal to the umbilicus. Once the urinary bladder is visualized a second trocar cannula is placed directly over the urinary bladder at the location of exteriorization. The bladder has to be under slight tension to create a straight tube to prevent stones to accumulate in dorsal pocket of the bladder. Using atraumatic forceps with multiple teeth the bladder is grasped and pulled into the trocar cannula as described in intestinal biopsy section. Once the apex of the bladder is exteriorized stay sutures are placed from the bladder wall. The bladder is temporally pexied to the abdominal wall. A small incision is made in the bladder wall, and a 5 mm cannula is introduced in the bladder. A suction line is connected to the cannula. The bladder is then flushed with sterile saline under pressure and the suction on the cannula. The telescope is introduced into the bladder. Bladder stones are usually suctioned with the cannula by the combine effect of suction and flushing. Forceps can be placed in the bladder along the telescope to obtain a biopsy or remove calculi. At the conclusion of the procedure the bladder is closed in a standard manner. The pexy is released and the abdomen closed in a routine fashion.

Laparoscopy is a minimally invasive technique for diagnostic and surgical procedures. Once the basic technique of laparoscopy is mastered and the appropriate indications are applied to the procedures it becomes a simple and rewarding addition to small animal veterinary medicine and surgery. As our ability advances newer diagnostic and therapeutic procedures will no doubt be developed.

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