Veterinary Vertex
Veterinary Vertex is a weekly podcast that takes you behind the scenes of the clinical and research discoveries published in the Journal of the American Veterinary Medical Association (JAVMA) and the American Journal of Veterinary Research (AJVR). Tune in to learn about cutting-edge veterinary research and gain in-depth insights you won’t find anywhere else. Come away with knowledge you can put to use in your own practice – along with a healthy dose of inspiration to remind you what you love about veterinary medicine.
Veterinary Vertex
Intradiscal Chondroitinase Injection as a Pragmatic Treatment for Down Dogs
We sit down with Drs. Paul Freeman and Nick Jeffery to discuss a treatment for down dogs that’s changing outcomes and conversations: percutaneous intradiscal chondroitinase injections that act like chemical fenestration, reduce extruded disc material, and help non-ambulatory dogs recover without opening the spine.
We walk through the origin of the idea, the ethical hurdles, and the growing dataset behind safety and effectiveness. You’ll hear why deep pain–positive dogs with acute disc injuries often do as well with enzyme injections as with decompressive surgery, and how careful case selection can minimize risk. We get practical about inclusion criteria—currently focused on dogs under 15 kg, with French Bulldogs now included under close monitoring—and the technical realities of needle placement, imaging guidance, and when to add MRI. We also dig into the strategy of treating three to five disc levels to lower recurrence, and why this multi-level approach could outperform single-site surgery over the long term.
The conversation doesn’t dodge the hard calls. We compare large compressive lesions versus primarily contusive injuries, discuss when early surgery still makes sense, and share early experiences expanding to cervical cases with ultrasound and fluoroscopic checks. Looking ahead, we explore research priorities: defining time windows for chronic presentations, tracking recurrence across breeds, and building the evidence to place chondroitinase correctly in the treatment pathway. We even touch on how AI could one day use imaging data to predict which dogs need urgent decompression and which can safely recover with enzyme-first care.
If you’re an ER vet, GP, or neurologist looking to offer owners real choices, this is a grounded, data-informed guide to a less invasive option that can preserve mobility and reduce euthanasia driven by cost. Listen, share with your team, and help more “down dogs” stand again. Subscribe, leave a review, and tell us: where would you place chondroitinase in your spinal care protocol?
JAVMA article: https://doi.org/10.2460/javma.24.12.0790
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SPEAKER_02:You're listening to Veterinary Vertex, a podcast that ADMA journals. In this episode, we chat about how the percutaneous enzymatic hemonucleolysis of intravertebral discs appears safe and effective with our guests, Paul Freeman and Nick Jeffrey.
SPEAKER_01:Welcome, listeners. I'm editor-in-chief Lisa Fortier, and I'm joined by our associate editor, Sarah Wright. Today, as Sarah just said, we have Paula Nick joining us. Hey guys, thanks so much for taking time out of your day to be here with us.
SPEAKER_03:You're welcome. It's good to be here.
SPEAKER_04:Yeah, it's great to be here. Thank you.
SPEAKER_02:All right, let's dive right in. So, Nick, your JAVMA article discusses the safety and effectiveness of intradiscal chondroitinase injection as a pragmatic treatment for non-ambulatory paraparesis and paraplegia in small dogs. Please share with our listeners the background on this article.
SPEAKER_04:Yeah, um, well, actually, it started with a conversation that Paul and I had uh many years ago, uh, discussing the recovery of with dogs that didn't have decompressive surgery when they became parapheritic or paraplegic uh following a disc herniation. And we were sort of going back through the history of the surgeries that have been done and realized that uh dogs that had non-decompressive surgery done had very good recovery rates. And so I've been sort of looking around for a way of doing like a fenestration type of surgery that was not surgical because as soon as you do fenestration, as soon as you do open surgery, then the obvious thing is you might as well take out any compressible material at the same time. And so it's difficult to make it to go back to doing fenestrations as an alternative. And so, really, the opportunity came when this company that produces chondroitase that I've been talking to for a long time were were talking to us about possibilities of using this in the spine, and uh it became obvious that that it was a possibility for doing a non-surgical penetration, really, and that's really background to it, I think.
SPEAKER_02:Yeah, I was really interested in this topic because I know these are often sometimes heartbreaking cases too. There's that big financial barrier, right? That big recovery barrier. So this is definitely super interesting of potentially we'll see, maybe a game changer or two for these cases.
SPEAKER_04:Yeah, it's uh we we both Paul and I have discussed this as well, but you know, we're quite distressed about hearing about animals that sort of become paraplegic or paraphernic with uh disc herniations or suspected disc herniations, and we're getting euthanased. Um and we thought we thought that that because the owners couldn't afford surgery, and so we were thinking that that's uh not really a very acceptable uh state of affairs.
SPEAKER_02:And Nick, what are the important take-home messages from this article?
SPEAKER_04:Uh well I think the the the big thing here is that uh the results that we got from the percutaneous disc injections were more or less the same as surgery. Uh we I I say more or less because the just statistically speaking, the numbers of cases that we've treated mean that we can't be uh as precise about the you know definition of success as we can be pretty sure with uh the results following surgery, just because hundreds of cases have been reported with surgery. And we we've just we by now we have done more than a hundred, and so we're getting pretty sure about the deep pain positive cases. The deep pain negative cases, we have got much smaller numbers, and so we can't quite be as sure about the recovery rate for those animals.
SPEAKER_01:That's fantastic numbers. Paul, other than it sounds like a few conversations with Nick over a few pints, uh, what sparked your interest in the use of chondroitinase uh for parapyratic and paraplegic, especially in small dogs?
SPEAKER_03:Yeah, I mean, it actually goes back before uh the conversation that Nick was talking about and and the work that we did um investigating the results of fenestration, to be honest. I I've got uh uh things that I wrote down and small presentation that I made uh years and years ago, uh, which Nick won't even remember, but it was when I was actually his resident, believe it or not. Um and uh and I had a case of a uh a deep pain negative uh peek and ease dog, Nick, actually, um, that whose hands couldn't afford surgery and we managed it medically and it actually recovered. And you know, it was a it was one of those sort of, I don't know, kind of light bulb moments or whatever. Uh, you know, and and I think everybody who who operates on these dogs regularly, which we all do, you know, as as neurologists, neurosurgeons, we we love doing the surgery because it's is very satisfying surgery. The dogs recover, you know, once you've done a few, it's pretty straightforward, generally speaking. Um, but I think everybody has this kind of question mark uh after a lot of surgeries where you kind of come out and think, well, did I actually achieve anything there? You know, was that really something that is actually going to make a difference to that dog's recovery? And I and I think we've, you know, we've discussed that a lot over the years. And and I think it was a case of sort of, you know, wanting to to try to um wanting to try to show that these dogs can get better and mostly do get better without surgery, first of all, but then thinking about um perhaps something uh that we could offer people who were not able to afford surgery, but who people were being told needed surgery as an alternative, because you know, otherwise the alternative is conservative management. And and you know, we've we've done a lot of work on that. We've shown that that generally works in most cases, actually, but people are still very scared of doing just conservative management on paraplegic dogs, particularly. Uh, and oh, you know, owners of dogs are very scared. And so actually being able to offer something that is perhaps more uh equivalent to surgery and maybe has some advantages over surgery as well. Well, definitely has advantages over surgery, but um, you know, it when Nick sort of put it to me about the chondroitase, I was instantly keen to be involved. Um, and we had to sort of get over a few barriers in terms of getting ethical approval to do this kind of thing in the UK. Um, but we managed to do that. And uh, you know, um I was a few months behind Nick getting started, but you know, now between the two of us, we've done yeah, well over a hundred dogs. And yeah, it's great. I mean, it's it's it's really taken off now.
SPEAKER_01:That's really fantastic. I think always uh, you know, you said well over a hundred dogs. Every time we look back at our own data, we're surprised um to find things that we just didn't expect. What were some surprising findings uh from this article and the data you accumulated?
SPEAKER_03:Yeah, surprising findings. I mean, I don't think we were surprised that the dogs were covered, to be honest. Um I think, you know, we we kind of expected that that would happen. You know, we were we were keen to show that it was uh a technique that was was doable. I mean, I was pretty scared uh of doing the first one or two, I'll I'll be honest with you, because uh, you know, I kind of envisaged the possibility of of not being able to get the needle into the discs and and you know, maybe causing some damage to structures alongside. And and but you know, the i we haven't had any of that at all. And I think maybe that's one of the perhaps surprising things that we we don't appear to have had really any complications in this, Nick, do we? Um that we're aware of at least.
SPEAKER_04:Yeah, I would agree with that. I I you yeah, I I agree with Paul actually. We I was thinking the same thing that it might be very difficult to position the needles, but it doesn't seem to be as difficult as you'd imagine. Um I agree, yeah. We I hadn't seen complications from doing it, of course. Now I say that next one we'll get a competition, obviously. Yeah. I I it it I agree that it's that's surprising, yeah.
SPEAKER_02:Very cool. Well, like I said, it's such a cool topic and sounds like a good, I guess, option for people to have in their toolkit, too, especially for these owners, like you said, where surgery might be too much of a financial constraint for them. So, what are the next steps for research into this topic?
SPEAKER_04:Yeah, I'd actually I'd I'd just like to come back a little bit. Yeah. Paul mentioned about the uh conservative therapy, and I think you know, there is quite good evidence that conservative therapy will work. But uh, and Paul's done a great study on that. But uh the the the slight gap in his study was the delay of time before the dogs went into the conservative study for some of the cases. And so in uh in our study with the chondroitinase, we've been trying to fill that gap to restrict entry to being very early on in the course because I think the big thing that neurologists in particular are worried about with these cases is that um they're gonna get worse. You know, if you don't rush into doing surgery, that they're gonna get worse. And I think that that creates a lot of tension for the neurologists and for the owner. Um, and they the owners feel pressured to make a very quick decision. And so one of the things that that you know Paul and I have discussed quite a lot again is that the possibility of using conjoitinase is the first line treatment, and then you know, cases that we imagine that some cases might not get fully better, they might have persistent pain, and then we could take them to surgery later. Although I think so far we've only had like one or two out of out of our 100 odd cases where we've felt that that was necessary. Is that is that correct, Paul?
SPEAKER_03:Yeah, yeah, it is correct. Yeah, I I had one case where the owner, after three weeks, wasn't seeing um uh a significant improvement, let's say, and uh found the money to uh to have an MRI scan and surgery. Um and we we took that dog to surgery and it did recover much more quickly once it had been decompressed. And and I think, you know, as as Nick said, one of the things that we're kind of discussing a bit and and thinking is that, you know, that this might be a better approach to a lot of these dogs to to you know delay the surgery for the ones that don't recover.
SPEAKER_01:Paul, is there a or or Nick, is there a weight or a size? Everything in the title and the manuscript or small dogs, is there a weight or a size limitation?
SPEAKER_03:Yeah, that's a that's a good question. I mean, we've basically done, we've kept it to dogs under 15 kilos um at the moment. That was the entry requirement for the original trial. Um now uh you know, we've at Cambridge we've kind of started to open it up. Um, we're opening it up to dogs that have been down for longer, for instance. Um I I think the big problem with going for bigger dogs will be getting the needles into the discs. You know, I think that it it's the the bigger the dog potentially the more difficult that will be. But uh, you know, I think it's some uh if we had the right case, let's say uh the owner with the dog that um needed that approach, then I I think now we'd be willing to to give it a try. I'd be willing to give it a try. I think Nick would be the same. We were discussing the French Bulldogs um actually just this week because uh we haven't done any French Bulldogs in Cambridge, but Nick was telling me he's done a lot in Texas. Um so that you know that's the next sort of step for us, is is you know, I've had loads of inquiries from owners of French Bulldogs um since this went crazy on social media. So um, you know, they will be coming uh for sure.
SPEAKER_01:How about how many levels have you like set? Like we're only doing one to start two. What do you advise or veterinarians to wanting to start this?
SPEAKER_03:Well, you mean levels of numbers of disks that we're treating? Yeah. So, you know, the original trial that Nick devised and that we both have followed with with the first uh cases, and and and uh that is what we've published was to treat four levels, four uh disk spaces. And part of the reason for that was that we're not we weren't MRIing these dogs. So we were basing where we were treating them on the results of the neurological examination. Um, and you know, that was one of the things that we always had to explain to owners um and and one of the potential limitations. Um what we're doing now at Cambridge is we're offering people an MRI scan um alongside treatment so that we can actually see precisely which disk has gone and target the disk that's gone. We've also got you know some information on uh the the the disks, how they look, how they appear on MRI in terms of their level of degeneration and perhaps uh their risk of um extrusion in the future. So uh, you know, we're able to consider which disks we're targeting. But I think I mean we're still generally treating three, four, or maybe five discs is is what I'm saying to people now. Um and you asked about future research. One of the things, sorry, I'm taking over this, Nick. One of the things that we have started looking at. You can just mute me. Uh one of the things that we've cut back. One of the things that we've started looking at because it it is recurrence. Um, because you know, uh one of the things that people say about surgical treatment is that dogs are less likely to have a recurrence than with conservative treatment. Well, A, we don't think that's necessarily true. Um B, it's probably only true if they're receiving multiple fenestrations. And so what we're kind of hoping is that by treating more than one disc at a time, effectively, as Nick said, we're chemically uh fenestrating the discs. We would anticipate that the recurrence rate might be lower, which will be another big advantage with this treatment over standard surgery with you know not doing multiple fenestrations. So um we're looking at that at the moment. That will be the the the next um project, hopefully, that we're um we'll publish.
SPEAKER_04:Yeah, I I for future things, uh I I can jump in there as well. So uh Paul's mentioned about doing other breeds, and certainly, yeah, we we're treating French trees. The original reason for for not treating them was purely to do with the respiratory problems. And uh now that the owners are uh are are paying for the treatment, we can explain to them that if they have to stay in the hospital, which sometimes they do, um, if we treat them in the afternoon, we sometimes keep them overnight, but they'll go into ICU so that they can be watched. But uh the reason for excluding them before that is because we were trying to keep the costs down for us as well because we were subsidizing what we were doing. But the French is uh being completely fine about it. One thing that Paul mentioned about doing bigger dogs, that the difficulty would be that in some Frenchies we're having to use three and a half inch spinal needles to be able to hit the discs. And so you can imagine if you were doing a pit bull, uh that you may have we may not actually just have long enough spinal needles, although, of course, we could go up a gauge, but we haven't got much experience with using larger needles than 20 gauge, and the error that you'd make in trying to hit those discs because you're starting so far away might make it more difficult to do. Um the the big progression that we're doing here in including new cases is to treat necks now. So we've started to um the reason was we had somebody come in with a uh a dog with a neck problem, pick and knees again as it happens, that had been paralyzed, unable to walk on on all four legs for a long period of time. Theon has had the scan done and then couldn't afford the surgery. And so we sort of like desperately arranged for this to be done as a compassionate use, and so we did treat the dog and and it got better. I mean, whether it's the whether it's the chondrotonase or not, you know, who knows? But we it it did get better and quite quickly. And so we then wrote the AUP to be to be able to enable us to recruit uh just neck dogs with chronic discs. Um but we're gonna again, like Paul says, we're gonna have uh an MRI to locate which disc we're treating, because we're doing this with ultrasound guidance uh along with the radiologists, uh, because I'm not very good at using ultrasound, and so they position the needle very close, and then I put it into the into the disc because uh I know what it feels like to get it in the right place, and we're checking it with radio grips and things. So it's a slightly more involved process, but we're we're moving into doing next as well. Yeah.
SPEAKER_01:Sounds like you might need to collaborate with your equine partners to find those longer, stiffer needles to get in there.
SPEAKER_04:Yeah, I know. I yeah, I uh I have had some experience of using a very long needle, uh very long spinal needles, but yeah, it's not something we'd see me use.
SPEAKER_03:I think the just to to uh come back again uh with one of the other areas that we're interested in, certainly I'm getting a lot of interest, and I'm sure you are as well, Nick, is is um you know how effective this might be on more chronic extrusions, because you know, as as we said, we've limited it to dogs that have been down for um uh 48 hours or or less up to now. And we're now starting to to open it up to to dogs that have been down longer. And uh, you know, I I think it will be very interesting to to see what's the sort of time limit in a sense. You know, how long uh can a disc have been extruded before chondroitinase is not likely to be effective? Um, because I think I I have the feeling that it will be effective for uh extrusions that have been there definitely at least a few weeks. Yeah, but we could do with some evidence for that.
SPEAKER_02:Makes sense. Very cool. I think it's episode two is a really good reminder for our first-line clinicians, like our ER clinicians, our GPs that are seeing these down dogs, right? Like at first clinical presentation, that there are a lot of options and to really present to owners the entire picture and not just we need to cut ASAP or consider euthanasia. So I think this is a really good reminder, that audience.
SPEAKER_04:Yeah. I think one of the things that we need to clarify with this treatment is just its place in, you know, in the treatment on Ethereum, as they like to say. So the uh, you know, you've got conservative therapy, got surgery, and you I think conjoitinase is now another realistic option. And so we need to know where to place that, you know, which dogs you give which to and at which stage. Um, and so I I've got a feeling of how we can develop this in the future, but we need more data to know whether whether what I'm thinking is is is the best way of using it. One of the things, for instance, is is the deep pain-negative dogs. We we see a quite a lot through this clinic, and some of them, when you see them on the scan, they have a massive compression, like huge compression. Some of them don't, but some of them do have a huge compression. And so my feeling is that some of those may be better treated with surgery, you know, quickly. Um, whereas the other ones that have got mostly a contusive injury where we've got longer periods to try and disintegrate the the extruded material, um, then the chase may be more appropriate for those. And so I we it'll take a while to collect the data to know whether that's the way that we're going, but I it's my sort of feeling at the moment.
SPEAKER_02:And do you see a role for AI in this area of research, Nick?
SPEAKER_04:Um Yeah, I saw that you put that on the list of questions. Um I guess I I the the the role of AI here, I think, is in image analysis, so that uh you know what everybody wants to know is what and neurologists really do need to know this, like which which cases need to have surgery and when. And you imagine that you could collect a lot of data, a lot of imaging data, and then ask and and then tell the AI, you know, what which ones got better and all this. And hopefully they might better work out which ones need to be treated quicker and that. But I I I don't know that much about using AI, but my guess is that you'd need thousands of images before you could um you know reconcile that. But I yeah, definitely for the future, yeah.
SPEAKER_01:Yeah, it's hard to know what the future of AI is. It's very difficult to keep up.
SPEAKER_04:Yeah, right. Yeah. Yeah. Every week you read something that that tells you it's got more potential than you thought it had, yeah.
SPEAKER_01:Yeah. Well, this next set of questions we ask are really important for the listeners. Uh, we'll start with Nick again. What is the one piece of information the veterinary team should know about chondroitase for presumed disc-associated paresis and paraplegia?
SPEAKER_04:Uh but it's a very realistic treatment for a large majority of animals that present with acute paraplegia. Or small braid dogs that present with acute paraplegia, yeah.
SPEAKER_01:Very good. And then, Paul, on the other side of the same equation, what's the one thing the client should know about this topic?
SPEAKER_03:I mean, it's almost the same answer, really. Uh I I think um, you know, it's the fact that there is an alternative to surgery. You know, we're I think we're trying to get this message out more and more that surgery is not the only treatment option, uh, that it's probably not an emergency in the vast majority of cases, um, you know, and try and take away that kind of fear and uh and anxiety that it that it drives in owners of dogs and also their vets, let's be honest. Um, you know, it it really does. And so I think the more things that we can do and and publish that try to dispel that, certainly the the less dogs will end up being euthanized because their owners haven't got the money. Um that's the that's the first thing.
SPEAKER_02:So now we get to ask you some fun questions. So, Paul, what is the oldest or most interesting item on your desk or in your desk drawer?
SPEAKER_03:That's uh yeah. So I was thinking about this.
SPEAKER_01:Why does Nick laughing?
SPEAKER_03:I don't actually know why he's laughing because you know what's on my desk. He's probably got a good he's maybe imagining what might be on my desk.
SPEAKER_04:Yeah, and partly what's in my desk.
SPEAKER_03:There's a couple of there's a couple of things that I was gonna say. First of all, the thing that I think is the that I have on my desk in my office at work, which um uh is an extremely nice thing to have, is just a little white marble Daxund statue. I don't own a Daxon's, but they have supported Daxon Breed and Breed Societies and charities have supported the work that um both Nick and I have been doing for a number of years, and and really, especially my work in Cambridge, that's for sure. Um but this was a gift from uh an Italian uh veterinarian who came and visited our department a few years ago, probably right more or less at the beginning of my time at Cambridge, actually. And when she left, she gave me this little white marble Daxon, and it's a beautiful thing. Um, it's apparently carved from a stone that's only available in the area of Italy that she comes from. So I kind of treasured it and it's it's really, really nice. So that's the one thing. The other thing I have, which Nick will also uh will know about, I have a box full of vertebrae from various species that belonged to um a neurologist called Professor Tony Palmer, uh, who I think is about 98 years old now. Um he still lives in Cambridge. Uh he worked uh well he was uh he was around a lot when uh Nick was at Cambridge, I know. Um he's a pathologist, really neuropathologist, and he's kind of collected all these um artifacts and items. And one of the things that I've been able to do while I've been at Cambridge is to pull all this stuff together. So I have this box of bones sitting on my desk, which um is a is a reminder of kind of where we've come from, really.
SPEAKER_04:I I could add a funny story to that as well, actually, that uh Tony Palmer left those bones. Uh he he found these horse bones from a horse wobbler and left them on my desk at Cambridge. And at the time I had a dog that came in to work with me. And uh I came back after going to do a consultation or something and found him eating oak.
SPEAKER_01:I I could have predicted that as soon as you said horse and dog. I was like, oh no, this isn't going to end well for the wobbler neck.
SPEAKER_04:Yeah, so some of them have probably got bite marks in.
SPEAKER_03:That's why a couple of them are a bit chewed, yeah.
SPEAKER_04:Yeah.
SPEAKER_02:I love that though. Spoken like a true neurologist. And then Nick, what's your favorite animal fact?
SPEAKER_04:Oh uh that all mammals have seven net vertebrae apart from sloths.
SPEAKER_02:Very nice. Another great neurofact. Well, thank you both for being here today and for sharing your article too with us. We really appreciate it. Like we said, I think it's gonna be really cool info for our listeners and readers.
SPEAKER_03:Thank you very much.
SPEAKER_04:Yeah, thank you for your interviewing us. It's uh it's something we did we uh, you know, we're keen to sort of develop this technique. And so it's we're passionate about it, Nick.
SPEAKER_03:We are.
SPEAKER_02:We can certainly tell. And to our listeners, you can read Paul and Nick's article in Japan. I'm Sarah with Lisa Portier. Be on the lookout for next week's episode, and don't forget to leave us a rating and review on Apple Podcasts or whatever platform you listen to.
