Tora the Tiger: Abdominal exploratory to remove a large intestinal mass.

Tora

Tora is a 15 year old, 500 lb. male neutered tiger housed at the Exotic Cat Rescue Center (ERCC) in Center Point, Indiana. Tora was presented to the Center's veterinarian, Dr. Fred Froderman, for acute lethargy on 4/21/14. Physical examination under sedation revealed pale mucous membranes and a large abdominal mass. Further diagnostics revealed a PCV of 24% and a mass in the abdomen visible on ultrasonography.

Tora was anesthetized the following day and an abdominal exploratory performed.

Tora under anesthesia just before surgery

Severe hemoabdomen, and a basketball sized mass of the jejunum was found. An intraluminal intestinal foreign body (calf hoof) was also found in the portion of bowel just proximal to the mass.

Removing omental adhesions from the mass.

The mass was removed by resection and anastomosis of the involved intestine. No other masses were evident in the abdominal cavity.

Large round well circumscribed mass of the small intestine in Tora

Abdominal closure was performed routinely.

Excised intestinal mass. Note intraluminal calf hoof in the bowel (arrows)

Tora received 4 liters of intravenous lactated Ringers solution while under anesthesia. Famotidine and sucralfate were administered for 3 days postoperatively.

Tora has made gradual improvement over the past several days and is now eating liver and slowly regaining his strength. Histopathology of the mass revealed a low grade soft tissue sarcoma (possible gastrointestinal stromal tumor). The margins of the excision were clean.

If Tora continues to do well his prognosis is good since the sarcoma is low grade and was completely excised.

Tora's mother was rescued from a circus and transferred to the rescue center in 1997. Tora was born at the center and has lived there ever since. He is an amazing creature and I felt very privileged to be asked to participate in his care.

For more information on the ERCC, see http://www.exoticfelinerescuecenter.org

Ovarian Remnant Syndrome in Dogs and Cats: Why does it happen and how to prevent it.

Ovarian remnant syndrome in dogs and cats: 

21 cases (2000–2007)

Rebecca L. Ball, Stephen J. Birchard, Lauren R. May, Walter R. Threlfall, Gregory S. Young

Journal of the American Veterinary Medical Association Mar 2010, Vol. 236, No. 5, Pages 548-553

Summary

The authors of this paper looked at clinical cases of dogs and cats with ovarian remnant syndrome (ORS) after ovariohysterectomy. The cases were from the veterinary teaching hospitals at The Ohio State University and University of California - Davis. Here are some key points of the study:

• The most common clinical signs were those of proestrus and estrus;
• Clinical signs in some cases took years to develop, even up to 9-10 years in 3 animals (Fig 1);
• Results of abdominal ultrasonography were suspicious for an ovarian remnant in 11 of 12 animals; 
• All residual ovarian tissues were in normal locations, not ectopic;
• Retained right ovaries were more common than left;
• Long term follow up on 18 cases showed resolution of clinical signs after surgical removal of the retained ovary.

The authors concluded from the study that the results indicated surgical error was the most likely cause of ovarian remnant syndrome. 

Commentary

Ovarian remnant may be more common than we think, especially considering the length of time that clinical signs can develop after ovariohysterectomy. In our experience the entire ovary is usually found, not a small fragment of it. Possible causes could be: separation of the ovary from the uterine horn during tugging of the uterus to exteriorize the ovary, or incorrect placement of hemostatic clamps when preparing it for removal. 

Ovarian remnant syndrome should be suspected in any dog or cat with signs of estrus or estrus-related disorders like vaginal hyperplasia or prolapse. Diagnosis can be substantiated via vaginal cytology, ultrasonography, and hormonal assays.

Key Point: Perform abdominal exploratory on dogs and cats with ovarian remnant syndrome while they are in heat. The ovary and associated vasculature will be easier to identify during this phase of the reproductive cycle.

Prevention

The ovaries, especially in obese animals, can be difficult to identify. Careful palpation of the firm, bean like structure is necessary in many animals to be sure that clamp placement is proximal to the ovary and on the vessels in the ovarian pedicle. Adequate surgical exposure is a key element in removal of the entire ovary. After removal of the ovaries and uterus, opening the ovarian bursa will confirm that the entire ovary has been removed.

Have you seen any cases of ovarian remnant syndrome in dogs or cats? Post comments or questions here or on Facebook. 

Case Outcome on Lucky: F/S dog with a vaginal mass (Did you get it right?)

Case outcome on "Lucky", a 4 year old female spayed dog with a large vaginal mass. (Fig. 1)

Fig. 1

Because of Lucky's history of intermittent blood tinged vaginal discharge, and the appearance of the mass, our clinical impression was that the mass was vaginal hyperplasia (also called vaginal edema). There was no history of the owners using any estrogen products on Lucky.  Vaginal hyperplasia would be more common in an intact dog, so we were suspicious that Lucky had an ovarian remnant. 

Abominal exploratory was performed and a left sided ovarian remnant was found. (Fig. 2) 

Fig. 2: ovarian remnant found on Lucky (arrow).
The left kidney (K) is just cranial to the ovary.

A uterine stump mass was also found. (Fig. 3) 

Fig 3: Uterine stump mass (arrow) on Lucky.
The urinary bladder (B) has been retracted caudally.

Both the ovary and uterine mass were excised. Histopathology confirmed a normal ovary and a uterine granuloma.

Postoperatively Lucky had an uneventful recovery and her vaginal hyperplasia gradually resolved over a period of a few weeks. 

Ovarian remnant syndrome (ORS) is more common than you might think. We will discuss the syndrome in more depth in the next blog.

Many of you made the correct diagnosis on this case.

Nice job!

What's Your Diagnosis? Lucky, a 4 yr old female spayed dog with a large vaginal mass.

Lucky

Lucky is a 4-year-old mixed breed spayed female dog that presented for a vaginal mass. The mass has been present for approximately 3 weeks and has not changed in size since initially noticed by the owners. Lucky is urinating and defecating without problems. She has no other history of medical problems, other than the owners have noticed occasional small amounts of blood tinged vaginal discharge in the past 1-2 years.

Physical examination of Lucky revealed a bright, alert, and well-hydrated dog with no significant abnormalities other than the vaginal mass. Vaginal exam revealed an intraluminal mass that appeared to originate from the vaginal mucosa. The mass was smooth, movable, and non painful. Rectal exam revealed no abnormalities.

Appearance of hind quarters and vaginal area of Lucky

Routine blood work (CBC and serum chemistry profile) was within normal limits.

What is your diagnosis?

How would you treat Lucky for this problem?

Answers to follow!

Are Purebred Dogs More Likely to Have Inherited Disorders? The answer may surprise you!

Prevalence of inherited disorders among mixed-breed and purebred dogs: 27,254 cases (1995–2010)

Thomas P. Bellumori, MS; Thomas R. Famula, PhD; Danika L. Bannasch, PhD, DVM; Janelle M. Belanger, MS; Anita M. Oberbauer, PhD. JAVMA, Vol 242, No. 11, June 1, 2013. Pg. 1549

Summary

In this study the authors analyzed data from dogs seen at a university veterinary teaching hospital. (University of California-Davis) The medical records were evaluated for dogs with one of 24 inherited conditions: different forms of neoplasia (hemangiosarcoma, lymphoma, mast cell tumor, osteosarcoma), aortic stenosis, dilated cardiomyopathy, hypertrophic cardiomyopathy, mitral valve dysplasia, patent ductus arteriosus, ventricular septal defect, hyperadrenocorticism, hypoadrenocorticism, hypothyroidism, elbow dysplasia, hip dysplasia, intervertebral disk disease, patellar luxation, ruptured cranial cruciate ligament, atopy, bloat, cataracts, epilepsy, lens luxation, and portosystemic shunt.

In 13 of these disorders there was no difference in prevalence between purebred and mixed breed dogs. Purebred dogs were more likely to have 10 of the inherited disorders, and mixed breed dogs were more likely to have 1 of the disorders (ruptured cranial cruciate ligament).

Disorders that were equally prevalent in purebreds and mixed breed dogs were all the neoplasms (hemangiosarcoma, lymphoma, mast cell tumor, and osteosarcoma), hypertrophic cardiomyopathy, mitral valve dysplasia, patent ductus arteriosus, ventricular septal defect, hip dysplasia, patellar luxation, hypoadrenocorticism, hyperadrenocorticism, and lens luxation.

Inherited disorders that were more common in purebred dogs were aortic stenosis, dilated cardiomyopathy, hypothyroidism, elbow dysplasia, IVDD, atopy, bloat, cataracts, epilepsy and portosystemic shunts. The only inherited disorder more common in mixed breed dogs was ruptured cranial caudal ligament. As a sidelight, mixed breed dogs were more commonly hit by a car than purebred dogs.

Commentary

The conventional wisdom is that purebred dogs are more likely to be affected by inherited disorders. In this study that was not true for all disorders, in fact less than half of the ones evaluated. Only 10 of the 24 disorders studied were more commonly found in purebred dogs, a surprising result of the research. Particularly surprising is the equal prevalence of hip dysplasia, patellar luxation, and patent ductus arteriosus between purebred and mixed breed dogs. These are all disorders that we generally think of being associated with specific pure breeds (German Shepherd-hip dyspasia, toy breeds such as miniature poodle for patellar luxation, and poodle for PDA). Hip dysplasia was equally expressed between purebred and mixed breed dogs in a previous study as well.

Dogs are thought to be descendents from just a few lineages of wolves. The authors postulate that the unexpected equal prevalence of many genetic disorders among dogs may be due to this history of domestic dogs. If true, genetic mutations would be widespread among all dog populations.

The findings of this study suggest that inherited disorders vary in their prevalence according to the disorder, not whether a dog is purebred or mixed breed. In other words, contrary to what we might think, mixed breed dogs get genetic disorders too! Hopefully studies like this will improve our understanding of genetic disorders in small animals and help devise strategies to eliminate them from future populations.

Post your thoughts about this interesting study!

Large Skin Defects in Dogs and Cats Treated With Axial Pattern Flaps (And one case where puppies are nursing from the leg!)

Fig. 1: Diagram of basic steps for caudal superficial epigastric axial pattern skin flap.
From: Birchard SJ, Smeak DD. Selected skin graft and reconstructive techniques. In: Saunders Manual of Small Animal Practice. 3^rd edition, Birchard and Sherding, eds., Elsevier, St. Louis, 2006. Pg 557

Axial pattern flaps are skin flaps that are developed using a major direct cutaneous artery as the primary blood supply.  Considerably more flexibility in the length and mobility of these flaps is possible compared to random skin flaps (e.g., the one used in Hershey; see blog from 2/24/14).  These flaps can be made with long vascular pedicles to transfer skin to more remote areas of the body compared to random flaps.  This is because of preservation of the direct cutaneous artery allowing adequate perfusion of a large area of tissue.  

Axial pattern flaps can be based upon many direct cutaneous arteries, such as the caudal superficial epigastric, cervical cutaneous branch of the omocervical, thoracodorsal, deep circumflex iliac, and the genicular branch of the saphenous artery.  The caudal superficial axial pattern flap is commonly used for large defects of the proximal thigh and flank.  The thoracodorsal axial pattern flap is used for defects of the distal humeral area or elbow. These 2 techniques will be described here.  However, other axial pattern flaps as listed above can be created using similar principles and are described in current veterinary surgical textbooks.

Indications

Indications for axial pattern flaps are similar to random subdermal flaps except that these flaps are used when the skin defect is very large. Large skin defects that occur due to trauma, mass excision, or other etiologies resulting in a loss of skin could benefit from this reconstructive technique. A major direct cutaneous artery and vein must be fairly close to the skin defect for this technique to be indicated.

Surgical Procedures

Caudal Superficial Epigastric Axial Pattern Flap

Use similar preparation and tissue handling principles described for advancement or rotation flaps. Be particularly careful when positioning the patient such that the vascular pedicle will not become distorted before planning your incisions.  Incisions are created as shown in Figure 1.  The mammary chain up to and including the 3^rd gland can be included.  Deeply undermine the flap just superficial to the abdominal fascia. Dissect very carefully around the origin of the direct cutaneous vessel to avoid inadvertent damage to this vessel that is vital to the survival of the flap.  Avoid creating a kink in the base of the flap that could obstruct blood flow. (Fig. 2)

Fig. 2: Caudal superficial epigastric axial pattern flap to close a medial  thigh wound

Drain the dead space if needed with a closed suction drain and suture the flap to the defect as described for the other flap techniques. Close the donor site after closing the flap.

Fig. 3: Healed caudal superficial flap on the stifle of a dog. Note nipples that have been transposed with the flap.

Fig. 4: Caudal superficial axial pattern flap was performed on this in tact female dog that subsequently got pregnant. Puppies are nursing from the transposed mammary glands on the leg. From: Pavletic MM. Axial pattern flaps in small animal practice. Vet Clin North Am Small Anim Pract. 1990 Jan;20(1):105-25.

Thoracodorsal Axial Pattern Flap

Fig. 5: Diagram of basic steps for thoracodorsal axial pattern flap.
From: Birchard SJ, Smeak DD. Selected skin graft and reconstructive techniques. In: Saunders Manual of Small Animal Practice. 3^rd edition, Birchard and Sherding, eds., Elsevier, St. Louis, 2006. Pg 557

A rectangular flap of skin is created based on the thoracodorsal artery (Fig. 6) 

Fig. 6: Thoracodorsal flap planned for this non-healing wound secondary to tumor removal followed by radiation therapy. Four previous attempts to close thewound had been performed. 
Lines indicate proposed incisions; X marks the origin of the thoracodorsal artery.

The flap is undermined deep to the cutaneous trunci muscle and rotated to cover the defect. A bridging incision is made if necessary to allow suturing the flap to the skin proximal to the defect. The flap is rotated to the defect and sutured in place. (Fig. 7)

Fig. 7: Same dog as figure 5 with completed flap

Fig. 8: Same dog as figure 5, 2 weeks postoperatively

Care and Complications (All flap types)

Restrict exercise until suture removal. Apply an Elizabethan collar before the patient is recovered from anesthesia and leave on the animal until the flaps are completely healed. Place a well-padded bandage on the front leg after thoracodorsal flaps are used to cover the elbow. Pressure necrosis of the potion of flap directly over the elbow can occur if not protected and cushioned. Change wound dressings as necessary.

Major complications resulting from skin flaps include local wound problems such as:  partial or total ischemia of the flap, infection, seroma, and dehiscence of the flap or donor suture line. Mild bruising of the flap for the first few days postoperatively is expected. Severe discoloration with a sharp demarcation between normal and abnormal skin is likely indicating flap ischemia and impending necrosis. Dehiscence of donor site incisions is usually due to excessive skin tension.  If dehiscence occurs, allow these areas to heal by second intention.

References

1. Birchard SJ, Smeak DD. Selected skin graft and reconstructive techniques. In: Saunders Manual of Small Animal Practice. third edition, Birchard and Sherding, eds., Elsevier, St. Louis, 2006. Pg 557
2.  Aper R1, Smeak DD. Complications and outcome after thoracodorsal axial pattern flap reconstruction of forelimb skin defects in 10 dogs, 1989-2001. Vet Surg. 2003 Jul-Aug;32(4):378-84.
3. Aper RL1, Smeak DD.Clinical evaluation of caudal superficial epigastric axial pattern flap reconstruction of skin defects in 10 dogs(1989-2001). J Am Anim Hosp Assoc. 2005 May-Jun;41(3):185-92.
4. Pavletic MM. Axial pattern flaps in small animal practice. Vet Clin North Am Small Anim Pract. 1990 Jan;20(1):105-25.