Author's Note: Dr. David Manobla has been supportive, open-minded and an integral part of this project. When we first became aware that RD could be a problem, he not only researched Renal Dysplasia himself, but he read the information I had gathered. Dr. Manobla has made many phone calls, searching for help from knowledgeable people. He learned how to do wedge biopsies, seeking guidance from a veterinary surgeon. I could have never tackled RD without his help. I am grateful and I would like to thank him.
I conducted the following interview with Dr. David Manobla on March 28, 1997, during a wedge biopsy of a kidney.
DM: I'm in the abdomen. Now I'll search for the kidneys. I'm pulling up the left kidney.
DR: Is the left kidney the one you always biopsy?
DM: The left one is a little more accessible. I'll isolate it. That's a normal looking kidney. There's a layer of capsule over the kidney. The blood vessels to the kidney are directly below the kidney. What I'm going to do now is to take what's called a wedge biopsy, which is a piece of kidney, going through the capsule, the cortex and the medullar part of the kidney. That's what we'll be sending in. The kidney has a fair amount of blood just because of what it does in the body, so when I cut into it, it will be fairly bloody. This is the piece of the kidney we're talking about. It will be sent off to two different labs. I'll put some gelfoam in, to slow down the bleeding. We're going to suture back up where we removed the piece of specimen.
DR: What kind of suture material are you using?
DM: #3-0 Maxon with swedged on needle. It is absorbable. The kidney tissue is extremely friable and not the best tissue to have to suture. On the other hand, having so much vasculature, the kidney does heal rather quickly.
DR: Do you use a different type of suture because it is so friable?
DM: No, not really. It's just the normal type of suture I use for spays and that type of procedure. It's just a certain limit to how tight you can tighten the suture because it will just tear out of the tissue.
DR: On the first biopsy you used strip gelfoam, but now you use powdered gelfoam. Do you have a preference?
DM: No, it is just whatever we get, actually. If we get it from one distributor it's the strip; the other one will send us the powder gel. They both work the same way. So, I usually put three or four sutures in the kidney. After that we'll apply some pressure for a couple of minutes to make sure the bleeding has stopped. Sometimes we have to hold it longer. This one's actually not too bad. The dog we did a couple of days ago seemed to bleed more than your other dogs, so we had to apply pressure for five minutes.
DR: Do you usually do the standard preoperative tests?
DM: Yes, we do a standard preop, check the BUN, ALT and protein level--total protein. If any of those come out abnormal, we will add a creatinine test, which is another test for kidney function. If any of the liver enzymes come out abnormal, we would run several more liver tests. When we are doing a standard preop it certainly wouldn't be a bad idea to do a clotting test on these animals, since we are involved with a fair amount of bleeding, to make sure that they do have normal clotting factors. Then we just premedicate them normally.
So, this is it. It's bleeding right now from where I placed a suture more than anywhere else. Now we'll time two minutes on the clock, putting some standard pressure on the incision. Hopefully that will be the end of the bleeding.
We'll cut the kidney specimen into two pieces. We'll send the larger half to Dr. Bovee at the University of Pennsylvania. Dr. Bovee will do the normal pathology report on it, looking for dysplastic cells in the kidney. The smaller piece will go to VetGen, where a chemical DNA study is being done, to try to make a non-invasive test for RD through either swab or blood test. The specimen to Dr. Bovee will go in routine formalin. The specimen to VetGen for the DNA study will go on dry ice, in a plastic bag. Recovery has been routine. We've done at least 10+ of these. We haven't had any post op problems. Try to keep them fairly quiet. You may want to put an older animal on IV fluids during surgery. That would certainly also be recommended.
DR: How about antibiotics?
DM: I personally don't routinely give antibiotics. Once again, if it's an older dog or if the animal seems to bleed more than normal, I'd certainly give them an injection of antibiotic post surgically and send them home on antibiotics.
DR: Do you think which lab the specimen is sent makes a difference?
DM: Yes, I think to determine the kidney cells you should send it to a pathologist that's familiar with this disease and who knows what they're looking for. The first one--when we necropsied Cisco--we sent one kidney to CSU and one kidney to Dr. Bovee. CSU did not find any renal dysplastic cells. Dr. Bovee did find dysplastic cells, so I believe that we should probably send these to one or two specialists in this field so that our results will correlate with each other.
Okay, so we'll release pressure on the kidney now. It's been several minutes and I'll see what we have here. It's bleeding a little bit. We'll put some more pressure on it. We'll put some more gelfoam on it. It's fairly quiet now. We'll put pressure on it for another minute and that should be the end of that. Then just a routine closure of the abdominal incision. We'll try to keep him fairly quiet for the first 48 hours. Cage rest is really the best way to go. For postop recovery we use a heated cage with some warm towels from the dryer. If I feel like the dog has bled more than I would like, I would give the animal IV fluids after the surgery or some subcutaneous fluids.
So far, these animals have recovered very uneventfully. We have not done urinalysis on all of these dogs. We are finding that urine results and blood results have been normal. We haven't had any abnormal kidney blood results, but we've probably had 50% of these dogs with kidney dysplasia. All the blood work has been normal. And the urinalysis that we have run have been normal. They're concentrating urine correctly. Normal pH. No signs of disease. Okay, I think we're going to pop that baby back in and sew him up.
DR: Why do you think it's important to get a percentage of fetal glomeruli reading?
DM: I think the percentage, at this point, is just giving us a handle on prognosis for that particular animal. Dr. Bovee would certainly be able to explain that better, but Dr. Bovee will tell us, from the percentages, life expectancy of that particular animal. And what the chances are of that animal coming down with clinical symptoms. Some people are using it as a gradient on whether or not to breed that particular animal. Most of the ones we have done so far have been mildly affected--anywhere from 2-5%. Any dog that comes back with 30% - 40% fetal glomeruli has a very short life expectancy of anywhere from 2 to 6 months, according to Dr. Bovee. And there's the moderately affected that come back between 10% and 15%. I believe, at this point we're thinking, at some point some of those dogs will show clinical symptoms. The ones that come back from 2-5% are believed to not show any clinical symptoms throughout their lives, although they are considered carriers of the disease. I believe most of ours so far have come back mildly affected. We've had one severely affected with 40% fetal glomeruli.
DR: When we first started exploring the options, when we became aware that this could be a problem, we talked about doing an ultrasound needle biopsy. Can you comment on that and why you decided wedge biopsy would be the best route to take?
DM: Well, once again, basically we're following Dr. Bovee's recommendations. He, at this point, I believe is the best specialist in this field. He believes that ultrasound guided biopsies do not give sufficient information. It certainly would have been much easier for us to do that, but Dr. Bovee feels that the information obtained from an ultrasound trucut biopsy--you're really only getting specimen from one area and you may miss catching any fetal cells at all.
With a wedge biopsy, it's a fairly large piece of tissue and doing the biopsy with that method, we are able to find the dysplastic tissue in the specimen. So, I would encourage everyone else to continue to do wedge biopsy as a means of diagnosing this problem. The wedge biopsies have seemed to give us very good information. I use a cutting needle. It has been recommended since the tissue is so friable to use a tapered needle. I haven't had any problems with a cutting needle. But it has been suggested to use a tapered as another option.
DR: So you have found this to be a somewhat routine surgery?
DM: After the first five or so. (Laughter) I had never done one of these before we started doing your dogs. The first several--I was a little nervous--but it really is not a difficult procedure at all. The only thing you need to be aware of is the hemorrhage that will be associated with cutting into the kidney. So far we haven't had any post op problems. I think the most important thing is to apply good pressure during the surgery and keep the dogs extremely quiet after the surgery.
Being that we've done so many dogs, we've tried to cut some of the costs out of it by not using fluids on every animal and not doing a barrage of blood testing. It would always be nice to do more lab work and put every animal on intravenous fluids, but when you're doing a whole breeding population it can get cost prohibitive. But there really is not a whole lot to it. It's fairly quick and not that involved, once you've done a couple of them. We've done 10 or so now and haven't had any problems at all either long-term hemorrhage or any other problems associated with surgery. We just do a routine closure of the abdomen. Are these the last two of your dogs to be biopsied?
DR: This is our second to the last. I was just thinking about when we first became aware of RD. What I'd like to comment on is--you weren't aware of this particular disease. I believe many veterinarians are not aware of RD. Can you say anything about that?
DM: I could. Basically, I think what's happening is that as of late, not just with this particular breed, but with a lot of breeds, we are beginning to realize that there are a lot of diseases that have been around for awhile and we have not realized it, both in the veterinary profession and in the breeding world. There is a book out now that covers genetic defects of every breed of dog. That book, I believe, is about 300 pages long. So we are becoming aware that a lot of these breeds have problems that we should be aware of, especially being veterinarians. It's very hard to know everything about every breed.
Obviously with something like this we need to become more aware of these problems and try to solve the problem or talk to the breeders and at least let them be aware of the possibilities of problems with these particular breeds. I think right now there are probably 15 or so breeds that have some type of renal problem on a genetic basis. Ten years ago we may have thought there may have been three or four breeds. We are becoming much more aware of problems.
I really think the only way to get to the bottom is to do just what you're doing. Find out who's affected and take care of the situation at that point. Certainly this breed is not the only breed where we'll find problems. The only way we will learn about this is to keep an open mind, be aware of the problems and try to address them and not hide the facts. Hiding the facts will basically slow down the progression of learning about the disease and becoming aware of it. It's not going to make the disease go away. I think the responsibility, with both veterinarians and breeders is to learn about your breed, learn about the breeds and what potential problems they have. To be aware of those problems. To try to find out which animals in the population are affected with it and to not use them as breeding stock.
DR: For me, the biggest eye opener was that mildly affected animals will live an asymptomatic lifespan. Prior to finding out about this problem, I thought my dogs were kidney disease free because they live long lives. That is what has been the most startling thing I've found out through learning and through biopsies on these animals that I've worked with for five generations.
DM: Right. Right. I think most people are not aware that just because they are asymptomatic and not showing any disease, that they can still have the disease and transmit the disease. That's certainly common with other problems as well. That's the surgery. It took us 20 minutes or so.
DR: Is there anything else you'd like to add?
DM: Just that it's really a fairly easy procedure to do and I would recommend that other breeders get in touch with their veterinarian or find a veterinarian that's willing to do a wedge biopsy if their veterinarian would not like to do it. Find another veterinarian in their area that would work with a breeder to help to solve this question about which animals are affected.
Dr. David Manobla will be glad to talk further with your vet about this procedure. If anyone is interested in a copy of the videotape for their veterinarian, I will send you one for the cost of a blank videotape, postage and the mailing envelope. Dr. Manobla's phone number is 303/670-0838.
Biopsy specimens should be preserved in formalin and sent to: University of Pennsylvania School of Veterinary Medicine, Laboratory of Pathology, Attention: Dr. Michael Goldschmidt, 3800 Spruce Street, Philadelphia, PA 19104-6051. Dr. Bovee's number is 215/898-8857. Phone calls must come from your veterinarian.