Pet Surgery Topics is a website I created to give pet owners a resource to learn about topics about veterinary surgery. As a veterinary specialist in surgery, I find that owners will often times try and research more about their pets condition either before or after visiting a specialist. Often times, this means turning to the internet to find out more. This is not a bad thing and I always like an owner who has come in after looking up what their pet has been diagnosed with to learn more about the condition and to try and be more prepared when I meet them. It means you care and you want to know the best treatment and be informed about what you are preparing to do for your pet. Let’s face it, they are one of the family and their care is just as important as anyone else in the family.
The problem I have found though is that there just isn’t that much good information on the internet for pet owners. Often, what I see on the internet is negative things, or people who had bad experiences, since let’s face it, those are the people who would take the time to write something out on the internet. So, my goal with this site is to try and provide a knowledge-base for pet owners from a specialist in veterinary surgery. My goal is not to diagnose pets with disease over the internet or to contradict what you have been recommended by your veterinarian. I just want to give pet owners a place to read about topics in veterinary surgery and become more informed about what options are out there. Veterinary surgery is a constantly changing field, just like human surgery. There are constantly new things coming up and new techniques for treating diseases which makes this such a great field.
This probably leads to the next obvious question, “Who are you and how can we trust what you say?” Good question. My name is Rob Vonau and I am a diplomate of the American College of Veterinary Surgeons. I live in Denver, CO and run a mobile surgery practice in the suburbs of Denver. I have been a boarded veterinary surgeon since 2002. If you would like to read my whole story, check out my “about me” page. As far as what is a diplomate of the American College of Veterinary Surgery stuff, read on in the next post to find out what it means to be a veterinary specialist.
I’m very glad you found my website and I hope you find the information here informative. This site is very new and I will try and post as often as I can but do have to work as well. If you like what you read, you can subscribe to my RSS feed or just bookmark this page and check it often. I have a lot of topics to discuss already but if there is anything in particular you would like to know about, drop me a message and I will try to post about it. Remember, I specialize in cat and dog surgery so there will be a fair amount of medicine topics that I may not have the answers for. Thanks again for stopping by and I hope you enjoy Pet Surgery Topics.
When we talk about dog hip dysplasia treatments, they are generally divided into treatments for immature dogs and treatments for adult dogs. This is because immature dogs have usually not developed arthritic changes and cartilage damage when we are addressing the hip with surgery whereas adult dogs tend to have moderate to severe arthritis and cartilage damage at the time of treatment.
Triple pelvic osteotomy, or TPO as it is commonly called, is a treatment used in immature dogs to potentially give them a more normal hip. The idea behind the surgery is to rotate the acetabular portion (pelvic side) of the hip joint outwards to give better coverage of the head of the femur. To accomplish this, requires cutting the pelvis in three locations, hence triple pelvic osteotomy, then rotating it outwards and securing it in the new position with a bone plate while it permanently heals in this new position. In the end, this procedure stops the subluxation of the hip joint do to the laxity of the structures holding the hip joint together.
The best candidates for triple pelvic osteotomy are young dogs, usually under 1 year of age and ideally closer to 6-8 months, with no signs of arthritis on radiographs. These dogs are the best candidates because chances are they have minimal damage to the articular cartilage within the joint, which will give them the best outcome long term with the procedure. These dogs should also have a good solid “clunk” or pop when their hip is checked for an Ortalani sign, or the ability for their hip to subluxate. Determining if a dog is a good candidate is usually done with a combination of palpating the hip and radiographs.
Commonly dogs will have hip dysplasia in both hips. Performing triple pelvic osteotomies is still indicated even if both hips are involved. The determination of whether to do one hip at a time, usually waiting about a month in between the two surgeries or doing both hips at the same time is a surgeon’s preference. Doing both hips at the same time can result in more complications but does reduce costs for the owner and healing time for the dog. With the advent of stronger bone plates used for doing the surgery, complications with doing both hips at once have dramatically decreased from years ago.
Complications associated with triple pelvic osteotomy include infection, implant failure, loss of some range of motion of the hip, narrowing of the pelvic canal, sciatic nerve injury, and if both hips are done at once, possible urethral entrapment. Implant failure, meaning breakage of the screws or plate or the screws pulling out of the bone, occurs because immature dog bone is softer than mature dog bone and thus doesn’t hold the implants as well. Infection can occur any time that an implant like a bone plate and screws are placed within the body. Usually the infection can be controlled by appropriate antibiotic therapy and the osteotomy will go on to heal okay. Sciatic nerve damage and urethral entrapment are both rare complications with triple pelvic osteotomies.
Recovery from triple pelvic osteotomy, in most cases, takes approximately three months. During this time, once the dog feels comfortable walking on the surgery leg, they can start taking controlled, short leash walks. If the follow-up radiographs taken at around 4-6 weeks show the bone is healing well and the implants are all holding up okay, then these leash walks are increased to help build up the muscles of the hind legs which were lost as a consequence of the surgery. Physical therapy done early in recovery can also help speed up recovery and help maintain more muscle after the surgery. Restrictions during the first three months are no off-leash activity like running, no stairs, no slick floors, and no playing with other pets. Activity level around the house can be confinement to a crate or confinement to one area of the house, depending on the surgeon’s preference. If both hips are done at the same time, the dog will usually need to be walked with a sling under their belly to help them get up and around for the first one to two weeks.
Prognosis with the triple pelvic osteotomy procedure depends largely on selecting the appropriate candidates but with the right dogs, they should have good to excellent long-term function. Studies do show that the majority of dogs will radiographically progress with arthritis over time but the majority of dogs are never clinical for this arthritis. Costs for triple pelvic osteotomy procedures varies greatly but in general run somewhere between $2000-4000 for one side and $4000-7000 for both sides at once.
The disease itself is a laxity to the structures that keep the hip joint tight. Although the dog is born with a normal joint, because there is laxity to the structures that hold it together, there is partial luxation of the joint during weight-bearing, termed subluxation of the joint. The consequence of this subluxation is abnormal wearing of the cartilage on the acetabulum and the head of the femur, microfracturing of the acetabulum, inflammation of the joint (synovitis), and progressive osteoarthritis within the joint.
Hip dysplasia is typically seen in large breed dogs such as Labrador retrievers, Rottweilers, German Shepherd dogs, Golden retrievers, and many others. It can be seen in smaller dogs and rarely in cats. Dogs with a low incidence of hip dysplasia include greyhounds, borzois, Irish wolfhounds, Afghan hounds, whippets, and salukis which tend to have a high ratio of muscle mass to body fat.
Dogs with hip dysplasia can present in two ways, either as a juvenile or as an older patient.
When juvenile patients present they are typically between 5-10 months of age. The signs that the owner can see are a bunny hopping gait, difficulty rising after rest, changes in jumping behavior, exercise intolerance, and popping or clicking noise while walking. A bunny hopping gait refers to the dog using the hind legs together when running so that it looks like a bunny hopping. On examination of these dogs, they typically show pain when the hind leg is pulled back or extended and a positive Ortaloni sign.
An Ortaloni sign is a test whereby pressure is applied dorsally or upwards towards the spine on the femur then the leg is abducted or moved outwards from the body. With a positive Ortaloni sign, when pressure is applied to the femur dorsally, the head of the femur subluxates out of the acetabulum then when the leg is moved outwards from the body, the head of the femur falls back into the acetabulum and a clunk or pop can be felt. Normal dogs will not have a positive Ortaloni sign since their hips cannot subluxate because the structures that keep the joint tight are normal. Lack of a ositive Ortaloni sign, however, does not guarantee that the dog does not have hip dysplasia. When checking for a positive Ortaloni sign, it usually helps to sedate the dog because it can be mildly painful and unless the dog is cooperative and stays relaxed, contraction of the muscles around the hip joint can give a false negative test result.
When a juvenile dog presents with signs of hip dysplasia it is usually due to the hip joint subluxating causing tearing of the joint capsule and the ligament within the joint. This leads to swelling of the joint termed synovitis. The dog presents for pain secondary to the synovitis within the joint.
The second way that dogs present with hip dysplasia is as an older dog. These patients have had hip dysplasia their whole life but never showed signs to the owner when they were young to say there was a problem. Unless the dog was specifically tested for hip dysplasia as a puppy, the fact that the dog had dysplasia would not have been found.
Owners of older dogs presenting with hip dysplasia typically see the dog is slow to rise in the hind legs, has a stiff or straight-legged gait in the hind legs, exercise intolerance, and has muscle atrophy of the hind legs. On exam, these dogs tend to have pain when the leg is pulled back or extended, reduced range of motion in the hips, and atrophy of the hind leg muscles. Rarely in these dogs can you get a positive Ortaloni sign because scar tissue has formed around the joint preventing it from subluxating.
Older dogs that present with hip dysplasia are showing signs of pain from osteoarthritis within the hip joint. The pain is no longer from the hip subluxating but now is from the changes that have occurred over the years. Over time, the cartilage within the joint wore away because of the subluxation and arthritis developed within the joint and these conditions lead to the pain that the dog shows.
Diagnosis of hip dysplasia is typically made with radiographs. The dog is laid on its back and both hind legs are extended straight back to give a ventrodorsal hip extended view. Normal hips will have good congruency between the head of the femur and the acetabulum and the dorsal acetabular rim will cover 50% or more of the femoral head. There will also be no signs of new bone formation, osteophytosis, around the joint.
In juvenile dogs with hip dysplasia, the head of the femur will be pulled away from the acetabulum and the head of the femur will have less than 50% coverage by the dorsal acetabular rim. Early signs of new bone formation, essentially arthritis within the joint, may also be seen even in dogs less than a year of age.
In adult dogs with hip dysplasia, new bone formation around the joint will be seen as well as flattening of the femoral head, a misshapen appearance to the femoral head, and a shallow appearance to the acetabulum. These are all changes that occur because of the laxity in the joint and at this point, the dog is considered to have end-stage osteoarthritis.
The ventrodorsal hip extended view is a good test to show if a dog that is having lameness has hip dysplasia as the source. It is always indicated to take radiographs to prove if the dog has hip dysplasia and not just assume it does because the signs and breed fit. There are many times when owners are told that their Labrador retriever that is becoming more and more lame in the hind legs has hip dysplasia as the source but in reality, the hips are normal and there is other problems like cruciate ligament tears, OCD of the hocks, or lumbosacral disease. The only way to know for sure that you have the right diagnosis is getting a radiograph and seeing changes to support hip dysplasia.
Because we know that hip dysplasia has a large genetic component, testing to try and identify dogs that have hip dysplasia before they are bred has been important for years. Orthopedic Foundation for Animals (OFA) is an organization that evaluates and grades dogs hips and certifies them as normal or dysplastic and keeps them all in a large database. When considering purchasing a puppy from a breeder, it is a good idea to know if they have been tested by OFA for hip dysplasia. Orthopedic Foundation for Animals uses the same ventrodorsal hip extended radiograph to certify dogs for hip dysplasia. Dogs must be two years of age or older to be certified. The radiographs are graded by a boarded radiologist and classified into one of seven grades. “Normal” hips can be excellent, good, fair, or near normal and “dysplastic” hips can be mild, moderate, or severe.
There have also been newer tests that have come about o try and test dogs at younger ages to see if they are dysplastic. Penn HIP (Hip Improvement Program) is a test that uses a means of applying distraction to the hip joints. Radiographs are taken in neutral position and in distracted position and a distraction index is calculated. The test is submitted to the University of Pennsylvania Penn HIP program where a database of pretty much all breeds is kept and the distraction index is compared to other dogs within that breed because there is some variation from breed to breed. The nice thing with the Penn Hip test is that it has been shown to be accurate as early as four months of age. Penn HIP radiographs must be taken by a veterinarian certified by the program to take them but there are many people doing them so finding someone usually is not difficult.
Another radiographic test that is sometimes done is the dorsolateral subluxation score. This test is similar to Penn HIP test in which radiographs are taken in neutral and when weight-bearing is simulated. It has also been shown to be accurate in younger dogs but is less commonly done. Other tests like CT scans or MRIs can also be performed but because of cost are less often done.
Although it is important to know if breeding dogs have normal or dysplastic hips, it does not guarantee that dogs with radiographically normal hips when bred will not have dysplastic puppies. Dogs can be a carrier for hip dysplasia and not show signs of the disease. Unfortunately, if two dogs who are carriers for the disease are mated then they can have offspring that has clinical hip dysplasia. So, unfortunately, even if dogs have OFA certification that their hips are excellent, they have a chance of producing hip dysplastic puppies. By testing not only the parents but all offspring for hip dysplasia and continuing to test for multiple generations is the only current way to feel comfortable that the disease is out of a line of dogs. Currently, one place having success with this is Guide Dogs for the Blind which does test all puppies and has made great strides to eliminating hip dysplasia from its dogs.
Another important note is that studies have shown that there is a poor correlation between clinical signs of hip dysplasia and radiographic findings. In one study, 86% of dogs with severe radiographic signs of hip dysplasia showed only mild signs at one year of age. This means that many dogs can have hip dysplasia on radiographs but never show signs of a problem. This is important when considering whether or not to treat a dog that shows signs of hip dysplasia on radiographs.
Canine hip dysplasia is a common developmental orthopedic disease that affects many breeds and usually both hips. The underlying disease is an instability within the hip joint that leads to subluxation and secondary degenerative joint disease. Hip dysplasia in dogs has a strong genetic determination but is also influenced by environmental factors such as nutrition and exercise.
The hip joint, or coxofemoral joint, in the dog is made up of the head of the femur and the acetabulum of the pelvis. Hip dysplasia puppies are born with normal hips. As they develop, the ligaments and joint capsule that keep the joint together become too lax and lead to the two bones being able to pull apart. This is the underlying disease of hip dysplasia in dogs.
When the head of the femur pulls away from the acetabulum, it partially luxates the joint, a condition we term subluxation. When the dog bears weight on the affected leg, subluxation occurs within the joint. This subluxation causes the head of the femur to put excessive pressure on the edge of the top part of the acetabulum called the dorsal acetabular rim. This dorsal acetabular rim is not used to having this excessive pressure and with time starts to develop microfractures and starts to wear down. The subluxation also leads to tearing of the ligaments that hold the joint together and the joint capsule which leads to swelling within the hip joint called synovitis. It is typically the synovitis which leads to the lameness that owners see when the dog is a puppy.
As the hip dysplasia dog continues to bear weight on the leg and the hip joint keeps subluxating, the dorsal acetabular rim continues to break down. This leads to the cartilage on the dorsal acetabular rim and on the head of the femur getting worn away which leads to secondary arthritis formation within the joint. Over time, the hip dysplasia dog is left with minimal cartilage on the two bones and an arthritic joint which becomes the source of pain in the mature dog.
Hip dysplasia in dogs is a multifactorial disease. It is caused by both hereditary factors as well as environmental factors. Hereditary factors are the primary determining factors in the disease. Meaning that dogs with any signs of hip dysplasia should not be used for breeding since they will likely pass the hip dysplasia onto the offspring. It also means that even if a dog does not show signs of bad hips, they can have the genetic make-up to produce offspring with hip dysplasia if bred to the wrong dog. This unfortunately, is why even with screening for hip dysplasia in dogs, occasionally a mating of two dogs that appear normal produces puppies that are affected with hip dysplasia.
Hip dysplasia in dogs is also influenced by environmental factors as possibly dysplastic puppies are growing. One big factor that has been shown to shorten the time to first appearance and increase the severity of canine hip dysplasia is abundant food consumption as a puppy. While overfeeding itself doesn’t cause hip dysplasia, it does maximize the trait expression in genetically susceptible dogs. The mechanism of how this works is not known but in multiple studies, dogs that were limited in their food consumption from 6 weeks to 1 year of age had a markedly reduced incidence and severity of canine hip dysplasia.
To try and prevent dogs from having hip dysplasia, it is recommended to screen both parents before breeding and to screen all offspring of a breeding to see if any of the dogs have the disease. In this way, a breeder can eliminate any dogs from breeding that are carriers of the disease. Also, in any puppy that is suspected to have a genetic predisposition for canine hip dysplasia to limit food consumption during the first year of life. Currently, I recommend in any high risk breed to feed 25% less than what you would normally give. This should result in the puppy appearing a little thin which is the desired body condition score we are hoping for.
Gastric dilatation-volvulus (GDV), often referred to as canine bloat, dog bloat, or gastric torsion, is a serious life-threatening condition in dogs. Gastric dilatation-volvulus is the process whereby the stomach turns on itself and fills with air resulting in an overdistention of the stomach and a decrease in the blood flow to the stomach wall. Left untreated, most animals will die from gastric dilatation-volvulus.
Gastic dilatation-volvulus is suspected to initiate with the stomach rotating on itself. The stomach can rotate anywhere from 90 degrees to 360 degrees, but often rotates between 220-270 degrees. When this occurs, the esophagus which goes from the mouth to the stomach gets twisted and the pylorus which is where the stomach empties into the intestines gets twisted, thus closing off any exit from the stomach. The stomach then becomes distended with air. The air is thought to come from the dog swallowing air (aerophagia) and not being able to eructate (belch) and from carbon dioxide formation within the stomach secondary to fermentation nd changes in the metabolism in the cells that make up the stomach wall. This air is essentially trapped in the stomach and the stomach continues to dilate as more of the gas gets trapped. This results in the stomach turning into a large balloon within the abdomen.
The dilated stomach puts pressure on the major vessels within the abdomen, the caudal vena cava and the portal vein, which reduces the amount of blood that is returning to the heart. This leads to signs of circulatory shock and damage to the heart due to lack of blood flow. This damage to the heart can manifest as arrhythmias which are commonly seen with GDV.
When the stomach twists and dilates with air, the vessels that provide blood supply to the stomach wall become compromised and lead to the cells that make up the stomach wall dying. If enough of the cells die, the stomach wall will become necrotic and ultimately perforate.
The spleen of the dog is intimately associated with the stomach and when the stomach rotates, the spleen also rotates. This can lead to tearing of the vessels that attach the spleen to the stomach, or lead to compromise in the blood supply to the spleen resulting in the spleen also dying.
Gastric dilatation-volvulus primarily occurs in large, deep-chested dogs. Classic breeds that get GDV are Great Danes, Weimaraners, Saint Bernards, German Shepherd dogs, Irish Setters, Gordon Setters, and Doberman Pinschers. We also see it in many other large and giant breed dogs as well as some medium and small dogs such as Shar-Peis and Basset Hounds. It tends to occur in middle-aged to older dogs but can occur at any age.
The cause of GVD is unknown. There have been many studies that suggest exercise after eating a large meal can predispose dogs to GDV. Feeding one large meal, feeding soy-based or cereal-based dry dog food, stress, feeding from a raised food bowl, rapid eating, and having a fearful temperament have all been found to be predisposing factors in studies. One factor that greatly increases the chance of having a GDV is having a parent with a history of GDV. It has been recommended to not breeding dogs that have a parent with a history of GDV because of this.
Recommendations for owners with high risk breeds currently are to feed several small meals a day rather than one large meal, avoid stress during feeding and anything that causes dogs to eat rapidly, restrict exercise before and after meals, do not use elevated feeding, and don’t breed dogs with a family history of GDV.
Nonproductive retching, hypersalivation, and restlessness are common signs seen with canine bloat. Owners may also see progressive distention of the abdomen and a tight or tympanic feel to the abdomen. Sometimes, owners just find the dog recumbent and depressed with a distended abdomen.
The diagnosis of gastric dilatation-volvulus is made with radiographs. Taking a radiograph with the dog laying on its right side shows a classic “reverse-C” or “double bubble” sign which is the gas filled pylorus sitting above the gas filled fundus of the stomach.
Other tests that are commonly run include bloodwork, plasma lactate concentration, and in some older dogs chest radiographs. Bloodwork is usually run to have a baseline for how the kidneys, liver, electrolytes, red blood cell levels, and platelet levels are before surgery. In most cases, the bloodwork is normal. Plasma lactate concentration has been found to be prognostic with higher levels being associated with gastric necrosis and a poor prognosis. Chest radiographs are commonly taken in older dogs with GDV to make sure there are no signs of metastatic disease to the lungs which would suggest some form of cancer in the body that has already spread. This is not always done and is strictly so owners know before deciding about surgery whether their older dog has any other life-threatening disease.
Initial treatment of gastric torsion in dogs is fluid resuscitation to improve blood flow then decompression of the stomach. On presentation, the first step is placing one or more intravenous catheters and providing large volumes of fluids to help with the circulatory shock. Other types of fluids such as hetastarch (synthetic protein fluid) and hypertonic saline (very concentrated fluid) are sometimes used to accomplish the same thing.
Gastric decompression can be performed by passing an orogastric tube (tube through the mouth into the stomach) or by trocharization of the stomach. Trocharization is a procedure where a large needle or catheter is passed sterilely through the abdominal wall into the stomach to allow the air to come out of the stomach. This is a temporary way of decompressing the stomach, allowing the dog to become more stable and reduce the circulatory shock being caused by the overly distended stomach impeding blood flow from returning to the heart. Passing an orogastric tube can be one in an awake dog but it is painful and most dogs resist the procedure. Also, because the stomach has twisted, the esaphogus is also twisted and sometime the tube is very difficult to get into the stomach.
Surgery is always indicated for treating gastric dilatation-volvulus. Decompressing the stomach through trocharization or passing of an orogastric tube is a temporary way of stabilizing the dog but surgery is always necessary to make sure the stomach is repositioned appropriately and to pexy the stomach so it cannot twist again. Surgery should be performed as soon as possible after the dog has been stabilized.
Once the dog is anesthetized, an orogastric tube is passed if it wasn’t passed initially. With the tube in the stomach, the stomach is usually lavaged to remove any food or gastric secretions that are within the stomach. This is not completely necessary but makes the stomach easier to manage during surgery when it is not full of a lot of food.
At surgery, a majority of dogs will still have the stomach twisted once the abdomen is opened. On occasion, the act of decompressing allows the stomach to move back into its normal position. Repositioning the stomach involves rotating it in a counter-clockwise direction putting the pylorus back on the right side of the abdomen and the fundus on the left. Once the stomach is repositioned, the stomach wall is assessed for any areas of necrosis. Necrotic areas appear purple to black in color and often the wall appears thinner than expected. If any area is questionable, it is recommended to remove the affected area. The spleen is also assessed during surgery. It is not uncommon for the vessels that attach the spleen to the stomach to tear when the stomach twisted. If blood supply to the spleen appears to be damaged then the spleen needs to be removed.
Once the stomach is in normal position and the viability of the stomach wall accessed, a gastropexy is performed to attach the antral region (right side of the stomach) to the right abdominal wall. This greatly reduces the chance of the dog being able to have the stomach twist again. There are a few methods for performing the gastropexy and which type that is performed is dependent on surgeon’s preference. In all cases, the main objective is making a permanent attachment of the stomach to the abdominal wall. With a gastropexy, the chance of a dog having a torsion again is under 10%. Without a gastropexy, the recurrence rate is around 80%.
Having to resect a portion of the stomach because the wall appears dead carries a much higher chance of mortatlity. In studies, dogs that required a gastric resection had a 60% mortality rate.
After surgery, dogs need to be monitored closely for arrhythmias of the heart which are very common. Arrhythmias can start immediately after surgery or within 12 hours of surgery and can last for 48-72 hours after surgery. If the arrhythmias are severe and clinically affecting the dog they may require treatment with anti-arrhythmics.
Another condition that can be seen after surgery is disseminated intravascular coagulation (DIC). Disseminated intravascular coagulation is a disease where the dog uses up all of its factors for clotting is blood due to the severe trauma that the GDV caused the body and results in an inability to clot the blood. This leads to spontaneous bleeding which can be life-threatening. DIC is rare but can commonly be seen if part of the stomach had to be resected. Treatment for DIC involves aggressive treatment with plasma and fluids.
Most dogs recover well from surgery and can start eating within 12-24 hours after surgery. If there are no arrhythmias and the dog otherwise appears comfortable and able to eat, it can often go home within 24-48 hours after surgery. Owners are instructed to minimize activity to
leash walks for the first two weeks while the abdominal incision heals. It is also recommended to feed the dogs smaller, more frequent meals after surgery. Two weeks after surgery, the dog can return to normal activity if it has recovered well.
Although going to surgery and performing a gastropexy reduces the chance of a dog twisting its stomach again, there is a chance that the dog can continue to have the stomach dilate with air. This is a rare occurrence but can be seen. These dogs represent in the future with a distended, tympanic abdomen but the stomach is in the normal position. Treatment involves passing an orogastric tube to relieve the gas within the stomach but surgery is not necessary since the stomach has not twisted. Why these dogs continue to have the stomach dilate with air is often never figured out.
Nowadays, prophylactic gastropexies are commonly being advocated in high risk, deep chested breeds. Often when one of these breeds is being spayed or neutered, or if an abdominal surgery is necessary for some other reason like to remove a foreign body from the intestines, a gastropexy is also recommended. For patients that are having the gastropexy performed during a spay or neuter, use of a laparoscope to assist in performing the procedure reduces the amount that the abdomen needs to be opened.
New technology is around that is bringing stem cell therapy to your dog. A company called Vet-Stem, Inc has come up with a procedure whereby adult stem cells can be harvested from a dog and then used to treat diseases such as osteoarthritis , tendon repair, and other possible things such as wound healing, bone healing, and liver disease.
To understand the concept, the place to start is by answering the question, what is a stem cell? A stem cell is a “primitive” cell found throughout the body that has the ability to differentiate into any type of tissue such as bone, tendon, ligament, muscle, etc. The idea is that these cells are very immature and haven’t started differentiating into any set type of tissue yet. So, with manipulation, we can make them differentiate into whatever we want.
There are two big categories of stem cells, embryonic stem cells and adult stem cells. Most everyone has heard of embryonic stem cells because this is where all of the controversy is in our country today. Embryonic stem cells come from the inner cell mass of embryos and are intended to form a whole person or animal. These are extremely powerful stem cells and have tremendous potential to help a lot of diseases but they do have some down sides. One downside is that because they are intended to form a whole creature, they have the potential to form a type of tumor called a teratorma. This has really only been seen in the laboratory but is still a small concern. Also, because they usually come from another person (fetuses), there is a chance of rejection because the body identifies them as a foreign being to itself.
The other type of stem cell is the adult stem cell. Most adult tissues (bone marrow, fat, muscle, skin, brain, nerve)have stem cells present within them. These stem cells are more differentiated than embryonic stem cells but still have the ability to differentiate into many types of tissue. An added advantage of these tissues is that they don’t form teratomas and they can be collected and harvested from a person and given back to the same person, thus no chance of rejection by the body. Currently, in dogs, we are able to use fat as a source of adult stem cells. I will discuss why fat is a good source in a little bit.
The reason stem cells are beneficial is that they are loaded with substances we call “trophic factors”. These trophic factors reduce scarring, improve blood flow, block cell death, and stimulate differentiation of the resident tissue to heal the damaged tissue. They also block the mechanisms of inflammation and can regulate the immune systems response to the damaged tissue. Stem cells also have the ability to find where the damaged tissue is and home in on that location. What this leads to is a reduction in inflammation, reduction in scarring, and an increase in repair of the damaged tissue.
As I said earlier, in dogs, the current area we are focusing on is using adipose (fat) derived adult stem cells. There are quite a few advantages to using fat as a source of stem cells over other tissues like bone marrow. A big advantage is that fat has a very large number of stem cells present within it.
It has over 500 times greater stem cells than bone marrow for the same amount of tissue. When harvesting bone marrow, because the yield per amount is lower than fat, you have to culture the bone marrow-derived stem cells for a few weeks to increase the population of cells. With fat, the stem cells just need to be harvested and not cultured so turnaround time is quicker. Also, fat is easy to harvest and there is a large amount of it present within the body. Because it can be harvested from the patient and returned to the patient, this also eliminates the chance of rejection by the body.
Regenerative medicine (stem cells) has advantages over traditional medicine (medications such as aspirin) in many ways. Stem cells function by not just using one receptor or pathway to work, but by using multiple pathways. They also can be delivered directly to the affected area or have the innate ability to home to damaged tissue. Once at the site of injury, they are able to differentiate into multiple different tissue types, induce repair, and stimulate regeneration. They also release substances into the area that have affects on the local tissues as well as tissues away from the damaged area. Medications pretty much function by one pathway of action or by blocking one particular substance but don’t have other abilities.
Currently, adipose-derived stem cell therapy is being used to treat osteoarthritis in dogs. There have been a few studies looking at treating advanced arthritis in elbows, hips, and knees of dogs, all of which have shown improvement in lameness within 30 days. These improvements have lasted for months and for some over a year with a single injection. Adipose-derived stem cell therapy has also been used in horses to treat tendon injuries/inflammation with similar beneficial results in lameness and improvements in the actual tendon healing. Current indications for dogs
are for osteoarthritis, polyarthritis (inflammation within multiple joints,
usually caused by the immune system), tendonitis/tendonosis (inflammation of a tendon), desmitis (inflammation of a ligament), and bone healing.
The process of treating animals with stem cells is a 3 step procedure. There is harvesting, processing, and reinjection of the stem cells. Harvesting the stem cells is a relatively simple procedure. There are 3 main locations where there is usually an abundance of fat that can be harvested from: inguinal region, thoracic region, and the falciform fat. Harvesting does require the dog to be briefly anesthetized and the fat needs to be harvested in a sterile manner so it does not become infected. Once harvested, the fat is shipped to the company, Vet-Stem, Inc., overnight where it is processed.
Processing the fat is a sterile procedure where the fat is minced, washed, enzymes are used to digest the unnecessary tissue to form a pellet of cells which then is resuspended and returned overnight in a sterile syringe for re-injection. The processing is done within 12 hours so the stem cells are available 48 hours after harvesting.
Injection of the stem cells into the patient can usually be done with just sedation. Although the stem cells can be injected intravenously, better results have been found with injecting them directly into the affected joints. When multiple joints need to be injected, you just need to plan during the harvesting to take a larger amount of fat to make sure enough stem cells are returned. Complications with stem cell injections are rare with only a few cases of mild irritation at the injection sites and an occasional pocket of fluid forming where the fat was harvested from.
There is great potential for the use of adipose-derived stem cells in many other canine diseases, not just arthritis. Currently, there is research into using them for liver disease, wound healing, immune-mediated disease, and ischemic disease. In people there are studies looking at adipose-derived stem cells for treatment of heart attack patients, Crohn’s disease, and graft-vs-host rejection diseases like with kidney or liver transplants.
If you are curious and want to learn more about adipose-derived stem cell therapy or want to find a veterinarian in your area that is doing the procedure, visit Vet-Stem, Inc website.
Meniscal injuries in dogs are a common occurrence secondary to cranial cruciate ligament injury. Isolated meniscal injuries without a torn cruciate ligament are very rare, however.
The menisci are two C-shaped structures within the knee that play a role in distributing the force of weight-bearing from the femur to the tibia as well as act in stabilizing the femur on the tibia. The idea is that the bottom part of the femur is made of two round structures called condyles. The area that they contact on the tibia called the tibial plateau is a relatively flat surface. The menisci help allow a round surface to have more stability on a flat surface and increase the area available for weight-bearing.
Almost all of the time for the meniscus in the dog to be injured there has to be some laxity or tearing of the cranial cruciate ligament. When the cranial cruciate ligament is torn, this allows the femur to slide off the back edge of the tibia and then as it comes forward, grab a portion of the meniscus in the back of the joint and drag it forward, resulting in the torn piece sitting between the femur and tibia. The torn portion of the meniscus is almost always on the back half of the medial (inner) side of the joint.
Clinically, dogs with a torn meniscus show lameness, often severe, to the point of almost nonweight-bearing. Some of these dogs may have had a mild lameness before it suddenly worsened because the cruciate may have been slowly tearing long before the meniscus got injured. Another sign of a meniscal tear is a “popping” or “clicking” noise, called a meniscal click, when the dog walks. This is due to the torn portion of meniscus sliding around during movement of the joint.
Diagnosis of a meniscal tear is usually made by visual inspection at surgery. There are no known nonsurgical methods of repairing a meniscal tear and most dogs will ultimately not use the leg unless the torn portion is removed. Inspection of the meniscus can be performed using arthroscopy or via an arthrotomy (opening of the joint). Most of the time, the meniscus is being visualized along with some surgery to stabilize the torn cranial cruciate ligament. In dogs, attempts to repair the torn meniscus have not proven success. Therefore, removal of the torn portion of the meniscus is the standard of treatment. Other procedures like ultrasound and MRI of
the knee have been studied and may be effective at diagnosing a meniscal tear, but are rarely performed since surgery is usually indicated to repair the torn cruciate ligament anyway.
Meniscal injuries can also occur after a dog has had their knee repaired for a cranial cruciate ligament tear. This occurs in about 1 out of every 15-20 dogs and can occur months to years after the knee has been repaired. udden onset of lameness that does not improve with time or rest is the typical sign. These dogs will return to good use of the leg in most cases with surgical removal of the torn piece of meniscus.
Prognosis for dogs with meniscal tears is typically thought to not be as good in the long term as for dogs without meniscal injuries. Because the menisci play a role in stability and force distribution within the knee, an increase in post-op arthritis is expected after removal. Which procedure is performed to stabilize the knee may also play a big role in arthritis post-op. Clinically most dogs still do very well after meniscal removal and stabilization of the knee for the cruciate tear and if severe arthritis does occur, it is usually much later in life.
Cranial cruciate ligament rupture in the dog is the most common orthopedic injury that veterinarians see. Although some dogs may do okay without surgery to stabilize the stifle joint, a majority of dogs will require surgery to get back to using the affected leg well. When we start talking surgery to stabilize the knee in dogs, there are multiple different techniques that are being done. Which technique that is chosen depends on many variables such as size of the dog, age of the dog, activity level of the dog, financial factors, and even surgeons preference.
As far as the question of is there one “right” technique to stabilizing the knee, the answer is definitively NO! I always tell owners that when there are multiple different surgeries advocated for doing the same thing, you know that there is no “best” way to do it. If there was, then there would only be one surgery recommended all the time.
The newest technique that has been introduced as a way to stabilize the cranial cruciate deficient stifle in dogs is the Tightrope Procedure. This procedure was introduced in 2008 by Dr. James Cook, PhD, Diplomate ACVS from the University of Missouri in collaboration with Arthrex Vet Systems, Inc. The idea behind the system is similar to the lateral retinacular suture that is regularly performed in small and medium sized dogs. With the lateral retinacular suture (also called the lateral fabello-tibial suture, lateral suture, lateral imbrication technique, and extracapsular repair) a couple of strands of heavy nylon suture are placed around the lateral fabella and through the tibial crest and tied in a figure-8 pattern on the outside of the knee to mimic the position of the cranial cruciate ligament within the joint and to stop cranial drawer otion within the knee. This technique works effectively in smaller and medium-sized dogs but tends to loosen in the larger breeds leading to less than optimum outcome long term.
The Tightrope procedure was developed as a less invasive method than the TPLO and TTA which require cutting the tibia (osteotomy), an easy to perform surgery, a technique that addresses all aspects of instability and which provides consistently good long term results, even in larger dogs. Anatomically, the Tightrope is similar to the lateral suture technique in that it is placing a heavy piece of suture outside the joint to stabilize the stifle. The difference is that the Tightrope procedure utilizes bone tunnels and toggles to attach the ligament directly to the bone rather than around other structures like the fabella. There is a thought that because the lateral suture wraps around the fabella which is held to the back of the femur by a ligament, that stretching or lateral displacement of the fabella or ligament holding the fabella occurs over time and leads to the lateral suture loosening, especially in the larger dogs. By attaching directly to the bone, there shouldn’t be loosening over time. The Tightrope procedure also utilizes a new product called FiberTape instead of heavy nylon suture. FiberTape, made by Arthrex Vet Systems, Inc, in studies has been shown to have dramatically better ultimate load and stiffness compared to nylon and less cyclical displacement. Because of this, FiberTape can be used in larger dogs with less chance of the suture material breaking and less chance of the material stretching and leading to laxity within the joint.
The Tightrope procedure involves drilling two holes, one across the femur and the other across the tibia. Landmarks for the hole placements are very specific so that once placed, the suture will be in the isometric (same or similar) position to the cranial cruciate ligament within the joint. The suture is passed through the holes and a toggle and button are used on the medial (inner) side of the leg to attach the material to the bone. The procedure is quick and technically easy to do. It works well with arthroscopy because it doesn’t require entrance into the joint. The benefit of this is a faster return to use of the leg post-op. Another advantage of the Tightrope procedure is that it should be less expensive than either the TPLO or TTA, since the surgery is quicker and there are less implants being used.
Recovery from the Tightrope procedure is similar to all of the other techniques done to stabilize the knee. The dog is able to use the leg when they are ready, hopefully the first week. Activity is restricted to on-leash only for a full 3 months post-op but leash walks are encouraged as soon as the dog is willing to use the leg. After 3 months of progressively longer leash walks, and if recovery has been without problems, the dog can return to normal, off-leash activity.
The Tightrope procedure is a relatively new technique so we unfortunately don’t have a ton of data to say complications and long term outcome. In the initial study performed by Dr. Cook, 24 dogs had the Tightrope procedure and 23 dogs had the TPLO procedure. The rates of complications were 12.5% for the Tightrope and 17.4% for the TPLOs which were statistically similar. Six month post-op evaluations showed as good or better outcomes in medium, large, and giant breed dogs with the Tightrope compared to the TPLO when it came to function on the leg and radiographic progression of arthritis.
Complications with the Tightrope procedure include infection of the FiberTape, loosening of the FiberTape, and subsequent meniscal injury post-surgery. Infection of the FiberTape can be a serious problem since once infected, it is very unlikely that the infection will be able to be eliminated from the FiberTape. Ultimately, this means the only solution for the infection may be to remove the FiberTape down the line. Loosening of the FiberTape has also been reported. This is usually caused by enlargement of the hole in the bone where the toggle or button are placed and then the toggle or button slipping into the bone itself. Sometimes this is associated with infection of the FiberTape also. Subsequent meniscal injury is a problem with any technique used to stabilize the stifle joint.
TPLO surgery is one of the many different methods of stabilizing a dog’s knee after a cranial cruciate ligament tear. The TPLO surgery involves cutting the top of the tibia and rotating the bone then putting a plate on the bone to hold it in the new position while it heals. Sounds pretty radical just to make the knee stable but it is a very effective way of stabilizing a dog’s knee. I’ll go further into exactly what is happening in a minute.
First, to understand why we cut the tibia, you need to understand the anatomy within the dog knee. In a human, the top part of the tibia where the femur comes into contact with the tibia, called the tibial plateau, is flat. Because of this, when a person has a torn cruciate ligament, they can get around pretty well without the ligament. What the cruciate ligament does is stop the knee from turning inwards, called internal rotation, and hyperextension, in a person, the knee bending backwards. A person, as long as they don’t want to twist and turn on their leg, can get around pretty well without their cruciate. The dog’s anatomy is different. Dogs have a slanted tibial plateau. On average, the slant is about 25 degrees (see diagram). The consequence of this slant is that when all the muscles around the knee joint contract, the tibia tries to move forward compared to the femur. This movement is what the cranial cruciate ligament in the dog has to stop. Consequently, the cranial cruciate ligament in a dog is stressed every time the dog takes a step on the leg. Like I discussed in the post about CCL disease in dogs, we think this is a big reason why dogs tear their cruciate ligaments with little to no trauma. Just slowly over time becoming lame on the leg because the ligament keeps tearing more and more over time.
The concept behind the TPLO surgery is to remove the slant to the tibial plateau. Essentially, what we accomplish by doing this is we put the tibial plateau at a 90 degree angle to the dog’s patellar ligament. This is an important concept that comes up again in another surgery to stabilize the dog’s knee called the TTA (tibial tuberosity advancement). With the TPLO, a semicircular cut is made completely across the tibia using a special saw. Once the tibial plateau is free, it is rotated a certain distance (7-9mm for most dogs) until the plateau now has about a 5 degree slant to it. In studies, around 5 degrees was found to be the optimal angle where everything is stable within the knee during a full range of motion. Once the plateau is at the appropriate angle, a bone plate is attached to it to keep it in that position until the bone heals (see diagram). Effectively, what we are doing is making so that the dog does not need his cruciate ligament anymore. In actuality, we do not replace the cruciate ligament at all. We inspect the joint to assess how torn the ligament is, remove the damaged portion of ligament, and make sure other structures within the knee like the menisci are okay. But, as far as doing anything to replace the torn ligament, we don’t. The whole effect in the end is that when a dog bears weight on the leg after a TPLO procedure, and all the muscles around the knee contract, there is no shifting of the two bones, effectively removing the need for the cruciate ligament. Why the dog can run, twist, turn, and do other things that they should need a cruciate ligament for without a problem, we don’t fully understand that. Probably other ligaments surrounding the knee take up that job. We do know though, from having performed this surgery on hundreds of thousands of dogs that they recover and do very well with the TPLO procedure.
Complications with the TPLO surgery mainly involve the bone plate and screws that we use to stabilize the bone and the fact that we have essentially fractured the bone and need to get it to heal. Breakage of the bone plate or screws is a concern but is a rare problem. Infection is a problem that occurs in about 10% of dogs. The plate, unfortunately, is right below the skin and has little tissue covering it so it is at risk of infection. Infection manifests as swelling, discharge, lameness, and fever. It can occur close to surgery (5-7 days) or can manifest as a low-grade mild infection that appears even months post-surgery. Delay in bone healing can occur and is usually either associated with infection or with breakage of screws that hold the plate on. With most TPLO surgeries, the tibia is completely healed around 8 weeks, 12 weeks at the latest. This is somewhat age dependent, with older dogs taking longer to heal, and activity dependent, with the more active dogs post-surgery taking longer. Another common problem we see are dogs licking their incision open so your vet should always send you home with an e-collar (lamp-shade) for your pet to wear for the first two weeks. There are some other more rare complications that your surgeon should mention to you also when you discuss the procedure.
TPLO recovery varies depending on the surgeon. In my hands, I have the owners restrict their pet’s activity for a full 3 months. Restricting activity is mainly the dog needs to be on-leash whenever outside and otherwise no running, jumping, playing with other dogs, and for the early recovery, no stairs. Dogs are encouraged to take leash walks once they are willing to put the surgery leg down. This is usually one week post-op. Owners can start with 5-10 minute leash walks and gradually increase the duration from there. After 3 months, if radiographs show the bone has healed, the dog has had no complications that set back the recovery, and the dog is using the leg well, they can return to their normal, off-leash activity.
So who is the TPLO procedure for? I recommend the TPLO procedure for any dog over about 40lbs. Dogs below 40lbs. can till have a TPLO surgery, but other techniques that are less expensive can lso be done in those size dogs. The more the dog weighs, though, the more a technique like the TPLO should be considered. Also, very active dogs, I usually recommend the TPLO or similar type of surgery. As far as what is the best surgery for your dog, that is something that depends on the surgeon doing the surgery, what you can afford, and many other factors. There is really no right and wrong answer to which surgery is the best for any specific case. This is still something that is hotly debated across the field of veterinary medicine. The key for owners is to take the initiative and become educated about the options for their pet.
Did you know that your dog’s knee, or stifle as we call it, is pretty similar to your own knee. Dogs have similar structures and ligaments within their knee is humans. Unfortunately, they are also prone to tearing or rupturing their cruciate ligament, just like people.
Dog cruciate ligament injury is a very common injury that veterinarians see. It is by far the most common disease that veterinary surgeons perform surgery for. A study in 2005 looked at the estimated economic impact of dog cruciate ligament injury for the year of 2003 and found it to cost pet owners $1.32 billion (JAVMA, 2005) and the incidence of dog cruciate ligament tear hasn’t really changed since 2003 except costs of repair have gone up.
The cranial cruciate ligament (or anterior cruciate ligament in a person) is the ligament that dogs usually tear. There are two ligaments within the knee joint that form a cross or x-shape, thus the name cruciate ligaments. The problem with these ligaments is that once they are torn, they do not heal. The ligaments do not have a good blood supply and no mechanism for repairing themselves.
In humans, some form of injury or trauma is usually necessary to injure your cruciate ligament. Like football players getting tackled and injuring it, or skiers falling abnormally and tearing it. In dogs, we do see some dogs that are running around and suddenly tear the ligament. We also, however, see dogs that injure their cranial cruciate ligament without any trauma to the knee at all. There appears to be some degeneration of the dog cruciate ligament that occurs allowing the ligament to partially tear and then progressively continue to tear more over time with minimal trauma. Often these dogs present with just a progressively worsening lameness, usually exacerbated with exercise. These partial tears almost always go on and progress to complete tears given enough time.
The anatomy of the dog leg is thought to be partially responsible for why these partial tears occur. Studies have shown that when a dog bears weight on their hind leg and the muscles around the knee contract, there is a desire for the tibia to move forward compared to the femur. This movement, called cranial translation, is stopped by the cranial cruciate ligament. Since the dog cruciate ligament is stressed everytime the dog bears weight, it is thought that this is part of the reason behind the degeneration and gradual tearing of the cruciate ligament over time. This also is a big part in why dogs do not do well without their cruciate ligament. Once the ligament is torn, every time the dog takes a step, the tibia and the femur shift on each other causing swelling and pain for the dog. It is a very rare dog that can get around well without their cruciate ligament and why most dogs end up needing surgery to get them back to using their leg normally.
So how do you know if your dog has a cruciate ligament tear? The main sign you would see is lameness. Often with partial tears, the lameness is mild and most noticeable with exercise. The other sign you often see is lameness or soreness after resting. Usually the dog will use the leg for exercise but after laying down for a while, will have difficulty standing and show lameness when trying to walk around. As the torn ligament gets worse, the dog usually will show lameness more often and then progress to the point of holding the leg up. With acute (all of a sudden) tears of the ligament, the dogs tend to go “3-legged” lame, holding the leg up and not bearing any weight on it. The acutely torn ligament is also much more painful and dogs will often show crying and whimpering because of the severe swelling that occurs when the ligament suddenly tears.
The diagnosis of a dog cruciate ligament tear is usually done by feeling the leg for abnormal shifting of the femur and the tibia. There are two tests in general that your vet can do to tell if the ligament is torn. The first is called a cranial drawer test and the second is the tibial compression test. Both tests are trying to show abnormal shifting of the femur and tibia that the cranial cruciate ligament should prevent from happening. When the ligament is completely torn, both tests produce significant movement of the two bones. With partial tears, the movement between the two bones may be very subtle and sometimes just feeling the leg is not enough to tell for sure if the ligament is torn. In almost all cases, radiographs help to prove a diagnosis by showing swelling and possible arthritis within the knee to support some form of injury. Final diagnosis is made at surgery either with arthroscopy (using a camera on a scope) or arthrotomy (opening of the stifle) to visual the torn ligament.
Treating dog cruciate ligament injury almost always involves surgery. Like I said early, it is unfortunately a rare dog that will do well without having some form of surgery to stabilize the knee. There are some small dogs, maybe 10 lbs and under, that can get around without their cruciate ligament, but a majority of dogs, and definitely the larger the dog gets, will not use the leg without the cruciate being repaired. Because the ligament will not heal, the only hope a dog has without some form of repair is that the dog’s body can somehow lay down enough scar tissue around the joint to make it stable enough for the dog to use it. This may be enough for some small dogs, but usually it is not sufficient for medium to large sized dogs. Physical therapy and rehabilitation may help dogs to strengthen the musculature around the knee and possibly allow some dogs to do well without surgery.
There are multiple options for dog cruciate ligament surgery. Usually, the decision on which technique is done for dog cruciate ligament repair is based on the surgeon’s preference and the financial constraints of the owner. Because there are multiple techniques for repairing the cruciate, there is obviously no one surgery that is perfect. The techniques that are currently done for dog cruciate ligament repair include the lateral suture extracaspular repair, intracapsular reconstruction of the ligament, fibular head advancement technique, tibial plateau leveling osteotomy, tibial wedge osteotomy, tibial tuberosity advancement, and tightrope stabilization technique. I will leave discussing these different techniques with their advantages and disadvantages for another time.