When Your Pet Needs Surgery - Anesthetic Monitoring

By Rebecca Ball, DVM, MS, DACVS-SA

Whenever a pet has to undergo a surgical procedure, owners are often very concerned about how their pet will handle anesthesia and if it is safe.  Unfortunately, some patients do not have a surgery that they need because of this fear.  Although there are always risks associated with anesthesia, there are things we do to help keep your pet as safe as possible during any operation and to minimize these risks. 


The Surgivet Advisor Monitor
 apexx-equipment.com

At Circle City Veterinary Specialty & Emergency Hospital, all patients are continuously monitored during surgery and anesthesia by both a special monitor and a person who is always with the patient during the entire procedure, recording vital signs and monitoring  progress.   Our surgical monitor records the patient’s heart rate, respiratory rate, continuous ECG, end tidal carbon dioxide level, blood pressure, and SpO2.

The heart rate tells us how fast your pet’s heart is beating.  The ECG tells us about the electrical activity of the heart.  A normal ECG is pictured below. 

 



 

Certain diseases can cause heart arrhythmias to occur and an ECG will alert the Doctor to any problems.  An ECG of a dog that developed an arrhythmia is pictured below. 



 

The respiratory rate tells us how fast your pet is breathing.  The end tidal carbon dioxide level tells us how well they are ventilating their lungs.  If a pet is breathing too rapidly and shallow during anesthesia, the end tidal carbon dioxide level will be low.  If they are not breathing deeply enough, their end tidal carbon dioxide level will be high.  The end tidal carbon dioxide is reported as both a number as well as a graph that gives us additional information about their breathing.  A graph of a normal patient is pictured below.

 

Your pet’s blood pressure is as important as your blood pressure.  Often, during anesthesia, the blood pressure will be low.  It is important to know this as low blood pressure can have negative effects on the kidneys and brain.  Low blood pressure can be treated with fluids and medications during surgery if needed.

The SpO2 level refers to the percentage of oxygenated hemoglobin present in the patient’s blood.  Hemoglobin is part of the red blood cell that carries oxygen from the lungs to the tissues.  A low value alerts us to the possibility that the patient may not be breathing enough or that there may be something wrong with the lungs causing the pet to be not getting enough oxygen.

If you have any concerns about anesthesia, please feel free to contact us. 

Oh Those Broken Bones

By Kate Fitzwater, DVM, MS, DACVS

Summer brings nice weather for all of us, including our four legged friends who like to run and play outside too. Unfortunately both dogs and cats can run out in front of cars or get into other trouble that may result in a broken bone. Long bone fractures are one of the most common orthopedic problems we see at Circle City Veterinary Specialty Hospital.   The most common bones to be fractured include the radius/ulna in the forelimb and the femur (seen here) or tibia/fibula in the hindlimb.

There are several variables of bone fractures that may make prognosis better or worse. If the joint is involved in the fracture, then osteoarthritis of that joint is highly likely after surgery, even if it is stabilized. Young animals can fracture through their growth plates, which may cause deformities as they heal. Also the bone may come through the skin, which is termed an “open” fracture and has a higher risk of infection than one where the fractured bone ends are contained within the muscle and skin. Young animals typically heal faster than older animals, which is great, unless the fracture is not identified until several weeks after the fracture occurs and the bone heals in an abnormal location.

Fractures can be fixed by multiple methods and one repair doesn’t work for all fractures. The most common repair is by plate and screws.  The following pictures show the repair of the fracture above using this method.   To add stability and help prevent bending forces, a pin was also added down the center of the bone. Animals can keep plate and screws for their entire life if they don’t develop an infection or loosening of the implants.

 

Another unique repair is called an external fixator, which places most of the hardware outside the leg, as seen in this picture. When the fracture heals, the fixator is removed, which also removes all the implants. This type of repair is excellent for open fractures that are infected so the implants can be removed and will not harbor that infection. The downside to this method is the cleaning of the pin tracts and weekly checks of the fixator to make sure it stays tight.

 

Most orthopedic implants are stainless steel, but titanium is also used. Other types of implants include: interlocking nails, pins, screws, or pins and wire combination.  Most fractures heal within 8-12 weeks. If animals are less than 1 year of age, fractures can heal within 4-6 weeks. Rehabilitation in an underwater treadmill in the early period after surgery is recommended.   This type of therapy encourages use of the operated limb so the patient can maintain range of motin and muscle mass without having to bear as much weight.  

 

What Can My Dog Chew?

By: Matthew Lemmons, DVM, DAVDC



Metal Crown to Repair Fracture

When you go to the pets stores, there are dozens of choices for dog chews, some even claiming to help clean teeth.  However there are choices which can be harmful to your dog’s teeth.  We need to realize that our dog’s teeth are no stronger than our own teeth and their bite pressure is as much as two and a half times our own.  So one may deduce that anything that could break our teeth, could break our pets’ teeth.  Bones, hooves, antlers and hard plastic toys are all common culprits when broken teeth are noted.  These teeth then need to be treated, often by root canal therapy or extraction.  Therefore our basic rule of thumb for appropriate chews for dogs is “If you think it is too hard to chew yourself, it’s too hard for your dog to chew”.  Toys and treats which are more appropriate are durable rubber toys like Kongs, rawhides, many dental chews and stuffed toys.  It goes without saying that pets should always be monitored while chewing to assure they are not eating large pieces of a toy which may become stuck in the stomach or intestines.

There are many dental chews and diets which are clinically proven to help keep the teeth clean.  These products have the Veterinary Oral Health Council seal of approval and can be found at vohc.org.  These products include Hill’s T/D, Greenies and Tartar Shield treats.  These provide a healthy alternative to hard toys which may harm your pet. 

 In conclusion, if you are looking for a treat to add to your dog’s regimen to keep his teeth clean, look for clinically proven choices found on vohc.org.  By all means avoid anything which may harm your dog’s teeth.  Remember, if it is too hard for you to chew, it’s too hard for your dog to chew.

 

Are Mixed Breed Dogs Really More Healthy?

By:  Scott Owens, DVM, MS, DACVIM

The assumption has long been held that the best way to avoid many inheritable diseases in dogs is to adopt a mixed breed dog, or a mutt.  While many of the well known inheritable diseases have been linked to specific breeds of dogs, no study has ever set out to show the lack of these diseases in mixed breed dogs, until now. 

A group of veterinary researchers from the University of California, Davis set out to investigate how frequently many of the commonly seen inheritable diseases would occur in mixed breed dogs as compared to pure bred dogs.  In contrast to many veterinary studies with very small numbers of dogs, this study analyzed 27,254 dogs with 24 various diseases that are known to be inheritable.  Some of the more common internal medicine diseases evaluated included Cushing’s disease, hypothyroidism, liver shunts, and Addison’s disease.  Other well known conditions included many congenital heart defects, various types of cancer including lymphoma and mast cell tumor, and multiple orthopedic conditions including hip and elbow dysplasia, as well as cruciate ligament tear. 

As was to be expected, 10 of the diseases were seen more commonly in pure bred dogs, including hypothyroidism, dilated cardiomyopathy, and cataracts.  Somewhat surprisingly, however, 13 of the 24 diseases that were evaluated did not show any bias towards pure bred dogs compared to dog of mixed breeding.  This means that there is no significant difference in risk of contracting one of these diseases for a mixed breed dog compared to a purebred.  This group of diseases included Cushing’s disease, Addison’s disease, hip dysplasia, and multiple types of cancer.  Cranial cruciate ligament rupture, a very common orthopedic condition, was actually seen significantly more often in mixed breed dogs. 

Inherited diseases are, by definition, associated with some degree of genetic mutation.  Since we know that all breeds of dogs originated from a common ancestral pool, and genetic diversification and breed selection / separation has only occurred in the more recent past, it stands to reason that diseases caused by genetic mutations long ago should not be found in any higher proportion in pure bred versus mixed breed dogs.  Genetic mutations that have occurred much later in the diversification process, for example causing hypothyroidism, likely will affect a smaller subset of dogs making pure bred dogs more at risk.  This may be better conceptualized using a family tree image.  The common ancestors may be grouped together in the “trunk” of the tree, and any mutation occurring in this area is likely to affect all branches.  A mutation that occurs on an isolated branch, or in the case of dogs after the selection process of specific breeds, is only likely to affect those specific breeds, and not the rest of the tree.

So how does this impact you when it is time to pick out a new companion?  There are many positive attributes to bringing home both mixed breed dogs available at the local shelter and pure bred dogs from a reputable breeder.  Deciding on what kind of dog to bring home should be a well thought out process, weighing all of the positives and negatives of the breed(s) involved.  The conclusion of this study should in no way detract from adopting a mixed breed shelter dog; it should just be one more puzzle piece to help make the most informed decision.  

Bellumori TP, Famula TR, Bannasch DL et al.  Prevalence of inherited disorders among mixed-breed and purebred dogs: 27,254 cases (1995–2010).  J Am Vet Med Assoc  2013; 242: 1549-1555. 

Clinical Trial Results in New Treatment

By: Terry L. Grieshaber, DVM, DACVD

Golden Retriever with Atopic dermatitis

On June 21 – 22, 2013, I attended a first-to-know meeting sponsored by Zoetis for its launch of Apoquel (oclacitinib). Oclacitinib is a Janus Kinase inhibitor which inhibits the function of many pruritogenic and pro-inflammatory cytokines. This drug was developed for the treatment of Atopic dermatitis in the dog. While I do not feel that oclacitinib should be used as a first line treatment for Atopic dermatitis, it is another option for treating this sometimes devastating disease. Oclacitinib will likely be available after January 1, 2014.

Circle City Veterinary Specialty & Emergency Hospital has been involved in conducting clinical trials to determine the effectiveness of oclacitinib for the past several years. My team and I are proud that we were able to contribute in even a small way to bringing this drug to market. Developing new treatment modalities is not a small undertaking and requires a true team. I thank those veterinarians who referred cases for these clinical trials and those clients (and patients) who chose to participate. Watch our e-mail newsletters and website for further updates.

Note: An additional and completely separate clinical trail for Atopic dermatitis is currently being conducted in our Dermatology Department where patients may still be enrolled. If you would like more information on this 2013 study, click here or contact our Dermatology Department.

 

TTA vs TPLO - Similar until there are complications

By: Kate Fitzwater, DVM, MS, DACVS

Cranial cruciate ligament rupture is the most common orthopedic injury in dogs. There are multiple surgical procedures that can be done to treat this disease, but two of the most popular “osteotomy” (cut in the bone) procedures are the TPLO (tibial plateau leveling osteotomy) and TTA (tibial tuberosity advancement).

Both procedures can provide excellent outcomes and both have their potential complications. Infection can occur with any surgical procedure, but with orthopedic surgeries that involve implants, the risk is higher. That is why prior to an elective orthopedic procedure, the skin is evaluated for infection and antibiotics are used during the procedure and postoperatively to lessen this risk. If a dog licks or chews at the incision, this is highly likely to result in an infection in the immediate postoperative period.  Late infections are also a potential possibility as well, because urinary tract, skin, oral, or ear infections can spread to the site of an implant or area of inflammation (osteoarthritis). If the site of an orthopedic surgery becomes infected, the implants have to be removed to clear that infection completely. This is because the stainless steel implants do not have a blood supply and the bacteria stay on the implant in a “biofilm”. The implants can be removed as long as the bone has healed.

 

When we are dealing with removal of TPLO or TTA implants, the level of difficulty and invasiveness is dramatically different between the two procedures. Below are radiographs of each procedure showing the metal implants. The TTA implants involve a cage (square) that acts as a spacer, and during healing bone grows into this cage. There is also a fork plate and screws that hold the osteotomy in place. When removing TTA implants, the fork plate and screws easily can be removed, but the cage must be “cut” out of the bone, leaving a large defect that has a high risk of fracture. This surgery to remove the cage that is encased in bone is invasive and difficult. The TPLO, on the other hand, doesn’t have a cage and only has a plate and screws, which can easily be removed because the bone doesn’t grow into them.

  TTA radiographs showing cage,
fork plate/screws             

 TTA radiographs showing cage,
fork plate/screws             



TPLO radiographs showing
plate/screws 

TPLO radiographs showing
plate/screws

 

 

 

 

 

 

 

 

 

 

 

 

 

So, when discussing the surgical options for a cranial cruciate ligament rupture, all the potential complications need to be discussed and the risks weighed. Infection risk is low at 7.4% (Gallagher AD et al. Implant removal rate from infection after TPLO in dogs. Vet Surg. 2012), but if it is your dog that needs the implants removed, the process is less complicated to have had a TPLO over the TTA!

“I can’t believe I ate the whole thing…”

By Rebecca Ball, DVM, MS, DACVS-SA

Kitrina is an 11 year old female spayed Shih Tzu mix that presented for gagging and restlessness after eating one of her favorite chew bone treats the night before. Kitrina, like many pets, really enjoys her chew treats.

 

Kitrina’s family veterinarian took an x-ray and suspected that she may have overzealously eaten the entire bone, whole! She received barium (a contrast agent that shows up  as white on x-rays) to see if it could help determine if she had indeed eaten the bone whole. Unfortunately the x-ray showed that she not only had eaten the bone whole, but that it was stuck in her esophagus.

Here is an x-ray that shows the barium (white) in Kitrina’s esophagus outlining the chew bone (black) stuck in her esophagus.

 

 

In this picture, the chew bone has been outlined with blue arrows.

 

Kitrina was referred to Circle City Veterinary Specialty and Emergency Hospital and evaluated to see if her chew bone could be removed with an endoscope. An endoscope is a camera that can be inserted into the esophagus and instruments passed through to grab and remove objects. Unfortunately, Kitrina’s chew bone was so tightly stuck in her esophagus that it could not be removed. Kitrina had to undergo emergency surgery to remove the stuck chew bone.

An incision was made through the side of Kitrina’s chest and another incision was made into her esophagus. The chew bone was successfully removed piece by piece and the incision into Kitrina’s esophagus was repaired.

The esophagus is a very delicate area to perform surgery on and because of the movement associated with swallowing and other anatomical factors, complications with esophageal surgery can be high. Because of these factors and the fact that the chew bone was in Kitrina’s esophagus overnight causing inflammation and irritation, it was decided that it would be best to allow her esophagus to rest for at least a few days after surgery to let it heal. In the meantime however, Kitrina would still need to eat! A gastrostomy tube (a tube inserted surgically through the skin into the stomach) was placed and allowed us to continue to feed Kitrina while also letting her esophagus rest and heal.

 

Kitrina did well after surgery and after one week she was allowed to begin to eat soft solid foods by mouth. Again, Kitrina did well and after two weeks her gastrostomy tube was removed and she was allowed to continue to eat soft foods by mouth and will begin to eat dry foods in the near future.

Kitrina’s family is delighted to have their wonderful dog back, healthy, and happy!