Neurectomy for suspensories in performance horse...why is this okay?

[Libby2563]

A lameness expert that I trust very much has unreservedly recommended surgery for my very young horse who has been lame for a month. Based on the exam and nerve blocks, he has diagnosed proximal suspensory desmitis and is recommending a neurectomy with fasciotomy. (An ultrasound will be done before surgery to confirm but he didn’t have any doubts about the diagnosis.)

I was really upset and spent days doing my own research. It seems that the chances of recovery are very low without surgery (14% is the number from the most-cited study) and quite high with surgery (85-90%)–“recovery” in the studies means that the horses are back to their previous level of work a year later. This vet has personally done over 150 surgeries and only had 3 failures. I’m inclined to do the surgery because there’s so little chance of improvement without it.

I know it’s not an uncommon injury or surgery, and have found several threads on COTH that have offered helpful information and encouragement. They don’t really address my specific doubts though (or if any do, I didn’t find them).

I’m having trouble understanding why a neurectomy is okay in a young performance horse. (I could accept it better as a last-ditch effort to maintain pasture soundness.) It seems like you are addressing the symptoms but not the cause, so damage could still be done to the ligaments but you just wouldn’t know about it, maybe until it’s too late. And, doesn’t it indicate some underlying lack of suitability to work? (My horse really wasn’t working very hard before he got hurt, so I’m really disturbed that it was enough to injure him in this way.) Am I missing something here? Ugh.

[Samantha37]

My horse was 8 years old when we discovered the giant holes in both hind suspensories (they were 1/3 the circumference of the ligament). This was in 2011. We suspect they were old racing injuries as they were most definitely not new, and I had owned him for a year before he came up very mildly lame. After the diagnosis (confirmed via ultrasound and blocks), my vet recommended the fasciotomy with neurectomy and PRP. They only gave my guy about a 60% of ever being sound enough to do be ridden at all (and he was only about a 1/5 lame at this point so I thought that was shocking).

I chatted with a friend who is a vet who works at one of the top practices in the country and she confirmed that that combination was the gold standard for treating hind suspensory injuries.

I went ahead and did the surgery as recommended, rehab, etc. Since then, he has evented through Novice (schooling Training), done the 3 foot H/J, and we are now showing 3rd level dressage. Prior to surgery we were showing Beginner Novice eventing (schooling Novice), and doing Training Level dressage. I would 100% do the entire procedure again.

The way it was explained to me was that the suspensory is essentially a “dumb” ligament that does not regenerate well, hence the fasciotomy. The neurectomy only nerves about an inch or so of the top of the ligament and it helps with the pain of the injury and getting through rehab. The nerves do grow back over time. I think because of this it is acceptable to do in a younger horse (the neurectomy portion of the surgery).

I was very worried initially that he would reinjure himself and I wouldn’t know because of the neurectomy but the vet said to watch for swelling and heat - signs of a new injury. I’ve been very lucky and I followed my vet’s instructions to the letter. I have had one issue since the surgery- last fall (2016), he aggravated the scar tissue that is on the ligament and had to have shockwave therapy and a rehab program again. He got solo turnout after that because we were quite certain he did it when he was running with his friends in the field.

Feel free to PM me if you want to discuss further. I also work in equine insurance so I am super familiar with this issue and not just from my own horse.

MTA: I feel like “nerving” is a scary as heck word because of all of the complications that come with nerving feet. It is the same thing but it doesn’t have the same possible repercussions that the foot nerving does (shredded DDFT, etc). It is literally only nerving about an inch at the very top of the suspensory - not the entire ligament or leg.

[mbv]

The way that it has been explained to me is that even after the actual suspensory ligament heals at the proximal attachment site under the hock, that it will always be enlarged compared to a completely normal suspensory, and therefore will mechanically irritate the deep branch of the lateral plantar nerve and cause pain even when the actual suspensory ligament is ultrasonographically healed. That branch is tiny and really only goes to that region (image: http://www.merckvetmanual.com/-/media/manual/veterinary/images/anatomy-for-tarsus-nerve-block-horse-high.jpg?la=en&thn=0). Usually horses with acute suspensory injuries will be painful beyond just what is processed by the deep branch of the lateral plantar nerve.

[Libby2563]

@Samantha37

The way it was explained to me was that the suspensory is essentially a “dumb” ligament that does not regenerate well, hence the fasciotomy. The neurectomy only nerves about an inch or so of the top of the ligament and it helps with the pain of the injury and getting through rehab. The nerves do grow back over time. I think because of this it is acceptable to do in a younger horse (the neurectomy portion of the surgery).

…

MTA: I feel like “nerving” is a scary as heck word because of all of the complications that come with nerving feet. It is the same thing but it doesn’t have the same possible repercussions that the foot nerving does (shredded DDFT, etc). It is literally only nerving about an inch at the very top of the suspensory - not the entire ligament or leg.

Ah, that is very helpful, thanks! I guess I didn’t understand that only a small part of the ligament will be nerved (though it makes sense). I did ask my vet about the nerve regrowing and he said it doesn’t, which is contrary to what I’d read before about neurectomies for navicular. I’ll have to ask him about that again.

I didn’t mention it but the vet also recommended PRP, so I’m glad to hear that combo worked for your guy! It’s great that you’ve been able to do so much with him, after he had what sounds like a relatively severe case!

[Samantha37]

@Libby2563

Ah, that is very helpful, thanks! I guess I didn’t understand that only a small part of the ligament will be nerved (though it makes sense). I did ask my vet about the nerve regrowing and he said it doesn’t, which is contrary to what I’d read before about neurectomies for navicular. I’ll have to ask him about that again.

I didn’t mention it but the vet also recommended PRP, so I’m glad to hear that combo worked for your guy! It’s great that you’ve been able to do so much with him, after he had what sounds like a relatively severe case!

It takes years but they definitely do grow back. I tell my horse’s story a LOT because he has done so much after a severe case and I think it helps people have hope. I remember going through it all like it was yesterday so I know a little hope can go a long way!!!

[joiedevie99]

I did one in February. The jury is still out on whether it worked. He doesn’t look as sound as I’d hoped at 9 months.

The reason for the nerving isn’t that you necessarily want or need to take away feeling. It’s that the origin of the hind suspensory is trapped in a very tiny space with a nerve ending. If the suspensory heals with any increase in diameter, which is typically the case, it can put pressure on the nerve, causing pain that isn’t the result of the injury.

[Action42]

To clarify a small point, the nerves can regrow, sometimes they do and sometimes they don’t.

As a vet, I recommend this procedure when the horse has lameness associated with the suspensory but has very few ultrasonographic changes to the structure of the ligament. The suspensory sits between the splint bones, and when it becomes enlarged, it can be made worse by the “pinching” of the splints on either side. That is why we often do the fasciotomy to allow the suspensory somewhere to go when enlarged that doesn’t generate more pain and inflammation.

The innervation of the proximal suspensory is controlled only by that deep branch of the nerve, so you’re not “nerving” your horse in a way that a palmar digital neurectomy “nerves” a navicular horse. The horse will still have most sensation intact but it will help with the pain during rest and recovery, allowing the horse to properly load the limb and rebuild strength and help the fiber pattern of the healing injury align with the normal fibers.

[Libby2563]

Super helpful clarifications on the nerving! Thanks all!

I am still bummed that this horse is only 4 and really wasn’t working very hard (because: 4) and couldn’t even hold up to that level of work. I’m not sure if that’s a rational way to think about it or not though.

[beau159]

@Libby2563

Super helpful clarifications on the nerving! Thanks all!

I am still bummed that this horse is only 4 and really wasn’t working very hard (because: 4) and couldn’t even hold up to that level of work. I’m not sure if that’s a rational way to think about it or not though.

I hear ya. My horse Red has different problems than yours (heel pain, both front feet) that I’ve been managing since I bought him when he was 6 years old. He too had been pretty much a pasture puff and he started showing faint signs of lameness when I put him into a regular exercise program.

Denerving is an option for him too. He’s going to be 12 next year and I’ve pondered it for him. Granted, he has different things going on than your horse, but I almost feel like 12 is “too young” to start trying to manage him with denerving.

I guess just like some humans, horses are just sometimes born with “defective bodies”. :winkgrin: Sounds like he’s very lucky to have ended up with a caring owner like yourself.

So I can’t offer you any specific advice on the procedure in question, but sounds encouraging from other COTH’ers.

[2tempe]

OP I have a mare w/ hind suspensory issues that I opted to retire. But during the thinking process, I read some things about the surgery and in the interest of more info is better, thought I would share: It has to do w/ the success rate of this surgery. Here is the link https://www.ncbi.nlm.nih.gov/pubmed/21883416. Below is the relevant info; it indicates that decision maker somehow needs to fully understand what is going on w/ the horse, the cause of injury and conformational aspects.

“Follow-up information was acquired for 155 horses that had undergone neurectomy and fasciotomy for treatment of PSD between 2003 and 2008. Success was classified as a horse having been in full work for >1 year post operatively. Horses were divided into 3 groups on the basis of the results of clinical assessment and diagnostic analgesia. Horses in Group 1 had primary PSD and no other musculoskeletal problem. Horses in Group 2 had primary PSD in association with straight hock conformation and/or hyperextension of the metatarsophalangeal joint. Horses in Group 3 had PSD and other problems contributing to lameness or poor performance. [h=4]RESULTS:[/h]
In Group 1, 70 of 90 horses (77.8%) had a successful outcome, whereas in Group 3, 23 of 52 horses (44.2%) returned to full function for >1 year. Complications included iatrogenic damage to the plantar aspect of the suspensory ligament, seroma formation, residual curb-like swellings and the development of white hairs. All horses in Group 2 remained lame.”

[Spotless]

When my gelding (JUST turned 5 at the time, not worked very hard, like your mare) tore a hind suspensory, the only thing we can figure out is that he got cast in his stall. He was just lame one morning and had a scrape on his forehead.

We ended up not having surgery (it healed fine on its own) but definitely considered the neurectomy and fasciotomy for him. If it was completely healed and he was still lame, we likely would have done it. I too thought that nerving was selfish and unnecessary, until it was my horse and his quality of life. Like others have said, it nerves a TINY section, sometimes it grows back and sometimes it doesn’t, and should only be done when the suspensory is healed, but enlarged or scar tissue is pressing on the nerve and causing unnecessary pain.

My gelding was also diagnosed with navicular three years after he tore his suspensory, but once we injected coffin joints and did corrective shoeing he’s been in regular work and completely sound ever since.

[Libby2563]

@2tempe

OP I have a mare w/ hind suspensory issues that I opted to retire. But during the thinking process, I read some things about the surgery and in the interest of more info is better, thought I would share: It has to do w/ the success rate of this surgery. Here is the link https://www.ncbi.nlm.nih.gov/pubmed/21883416. Below is the relevant info; it indicates that decision maker somehow needs to fully understand what is going on w/ the horse, the cause of injury and conformational aspects.

“Follow-up information was acquired for 155 horses that had undergone neurectomy and fasciotomy for treatment of PSD between 2003 and 2008. Success was classified as a horse having been in full work for >1 year post operatively. Horses were divided into 3 groups on the basis of the results of clinical assessment and diagnostic analgesia. Horses in Group 1 had primary PSD and no other musculoskeletal problem. Horses in Group 2 had primary PSD in association with straight hock conformation and/or hyperextension of the metatarsophalangeal joint. Horses in Group 3 had PSD and other problems contributing to lameness or poor performance. [h=4]RESULTS:[/h]
In Group 1, 70 of 90 horses (77.8%) had a successful outcome, whereas in Group 3, 23 of 52 horses (44.2%) returned to full function for >1 year. Complications included iatrogenic damage to the plantar aspect of the suspensory ligament, seroma formation, residual curb-like swellings and the development of white hairs. All horses in Group 2 remained lame.”

Well, crap… I have done a lot of googling but had not found this particular study yet, thank you. According to the vet, my horse does not have straight hocks but does have hyperextension of the fetlocks. I don’t think it’s very extreme, but it’s noticeable enough that it made the vet immediately think PSD. He did say this makes the surgery less likely to be successful but did not make it sound hopeless, like this study does. I don’t think I have particularly good alternatives and I feel like I have to try something since he’s a young, wonderful horse.

If I may ask, did you choose to retire your mare because she fell into one of the groups where surgery is less likely to be successful?

[2tempe]

OP - My mare was diagnosed w/ suspensory desmitis in both hind legs - “possibly” degenerative. This is one of many things she (and I ) have dealt with: Two colic surgeries, one case of enteritis, one case of “wither trauma” which caused her much pain and 8 weeks of nothing on her back, did I mention the stifle inflamation? She is now pushing 16 and I replaced her as my primary dressage horse after missing 3 yrs of showing. She was on lease for a year to a lower level rider, and had come back maybe 5 months prior to this diagnosis. I opted for retirement given the iffy prognosis, the long rehab, the amount of $ I’ve already put into her and the fact that she is not my primary horse. At the moment she’s happy and not noticeably unsound as she flits around the pasture…

[Samantha37]

@Action42 thanks for clarifying!!
I will say that my horse has quite good conformation - not perfect but hind limbs and pelvis are incredibly well put together, so that I’m sure had a hand in our positive outcome.

[findeight]

@Libby2563

I know these aren’t proper conformation shots, but they’re what I have on my phone at the moment. Can anyone comment on the degree of fetlock hyperextension here?

I’ve been watching videos of him trotting in slow-mo too and it doesn’t look much more flexion of the joint than most other horses. Look at this pic of Blue Hors Matine: https://countryrebel.com/blogs/videos/65991811-the-horse-starts-trotting-what-happens-next-will-blow-your-mind (note the comment: “The horse’s ability to memorize this dance and do it so well is amazing! We’ve never seen anything like it!!” :lol:).

Um…is he wearing boots here? Probably be best to pose him for a conformation shot, can’t tell much off these.

[TequilaMockingbird]

My 8 year old mare just had this exact surgery this morning on both hind legs. She was diagnosed in June with blocks, xrays and an ultrasound at Texas A&M. They would have also preferred an MRI but I opted against it because the MRI cost nearly as much as the surgery itself and requires full anesthesia. She went totally sound in both hind legs with the suspensory block.

She had enlargement in both right and left ligaments and a lesion on the right based on the ultrasound findings. She was put on stall rest for 6 weeks and then limited turnout for the remainder. I had two followup ultrasounds done to confirm that both ligaments had fully healed. They required them to be fully healed before doing surgery.

I went ahead with the surgery as it is likely to become a chronic issue without the surgery. The vets told me that once the ligament has been damaged, which causes enlargement, it stays permanently enlarged. That is the point of the fasciotomy, to give the ligament more space.

The surgeon (not the same vet that diagnosed her) did a brief lameness exam when we dropped her off yesterday. He said he will not perform the surgery on any horse that shows dropping in the fetlock. He said it may indicate underlying weakness in the ligament that the surgery cannot fix.

[Libby2563]

@"findeight

Um…is he wearing boots here? Probably be best to pose him for a conformation shot, can’t tell much off these.

Well, in one of the three photos he’s wearing front bell boots but that’s it.

Tequila, thanks for sharing your experience! I hope all goes well with your girl!!

@TequilaMockingbird

The surgeon (not the same vet that diagnosed her) did a brief lameness exam when we dropped her off yesterday. He said he will not perform the surgery on any horse that shows dropping in the fetlock. He said it may indicate underlying weakness in the ligament that the surgery cannot fix.

That makes sense to me too. I’m just not sure what is considered a dropped fetlock, honestly. A lot of the photos online are so extreme (and terrifying) that it’s hard for me to tell how my horse compares to a more mild case. I think I kind of just have to trust that the vet wouldn’t do the surgery if he didn’t think it was the best option, you know? I have a lot of respect for him based on past experiences.

[Montanas_Girl]

@Libby2563

I know these aren’t proper conformation shots, but they’re what I have on my phone at the moment. Can anyone comment on the degree of fetlock hyperextension here?

I’ve been watching videos of him trotting in slow-mo too and it doesn’t look much more flexion of the joint than most other horses. Look at this pic of Blue Hors Matine: https://countryrebel.com/blogs/videos/65991811-the-horse-starts-trotting-what-happens-next-will-blow-your-mind (note the comment: “The horse’s ability to memorize this dance and do it so well is amazing! We’ve never seen anything like it!!” :lol:).

Your guy’s hind pasterns do look long/weak. If the vet has mentioned “hyperflexion”, he’s probably hinting at ESPA (formerly known as DSLD). I don’t want to scare you, but, if that is the case, the prognosis is not good. I just lost a horse to this awful disease, and he did NOT have fetlocks that looked like your horse’s until very, very late in his life. You can read more information about ESPA in this article: https://www.thehorse.com/(F(tOTIdk-Bc1amWNVfRLwa2aKPQhVclry1h1l_lLpqhbxoTzCMBIMCcVWzYrzX0U_mIP4IsS_-Bxq50KvGq3aarQ24liQmys3agwrLo55e5Fp2WShL6QEkVgHpunG1zLBNnqe-D_oiWeyGfoadM3LNtvWga3OApNPLSiwYPK_EGapnFqRuq4Z7hMUoZ3icDr3EWRwahw2))/articles/24705/degenerative-suspensory-ligament-desmitis-update.

I considered the surgery you initially asked about for my horse. I decided against it because, at the time, he was 19 and semi-retired due to a previous front limb injury and Cushing’s Disease. Had he been a younger horse, I would have done the surgery. As others have mentioned, this isn’t the same as the kind of neurectomy performed on Navicular horses. Hind suspensory injuries are incredibly difficult to heal, so every little thing that can help is worth trying!

[quietann]

Had this done on the LH for my little mare back in 2010. The neurectomy was just part of the package to get the best possible result. She definitely has straight hocks, no fetlock drop at all though. I would say her recovery was to ~90%. With a lot of maintenance, she’s remained reasonably sound; for showing, I would not have gone recognized as the chances of her being “a little off” were too high, and the standards for soundness are probably higher at a recognized show than a schooling show. It’s been frustrating at times, but would have been way more frustrating if I had not also been hurt and subsequently reduced my competition aspirations for her.

[halt]

Do you have better confo pictures OP? Taken straight from the side, with no sun glare, or tail or boots obscuring the legs? I don’t see dropped pasterns from the pictures but he is straight behind from what I can make out of the shadows.

Before you do the surgery I would do a nuchal biopsy to 100% rule out ESPA/DSLD.