Hyperthyroid surgery

Re: Hyperthyroid surgery

David Mills — Fri, 21 Feb 2014 00:21:08 GMT

[quote user="Tim Charlesworth"]

Hi David - which technique did you use for your cats and is that recurrence of the thyroid mass that you are reporting or recurrence of hyperthyroidism (ie recurrence of 1st side and/or 2nd side misbehaving)? Interesting either way,

Tim

[/quote]

Hi Tim, there were a few surgeons involved, and a mixture of extracapsular (approx 20%) and modified intracapsular techniques. No difference between in terms of rate of recurrence, but numbers on low side for extracapsular. All recurrence (just over half of cats recurred; about 25% died before recurrence 'time' was reached and about 25% never recurred) were either contralateral enlargement (90%) or no goitre (10%), latter I suspect was ectopic intrathoracic tissue. The latter was interesting as I had always been suspicious of intrathoracic significance, and had suspected it was a bit of an Intervet spin.

Re: Hyperthyroid surgery

Tim Charlesworth — Mon, 17 Feb 2014 11:52:53 GMT

[quote user="David Mills"]

For those that are interested, I'll be presenting an abstract at BSAVA this year on this very subject.

101 cats assessed, recurred in 40%, with median time to recurrence after unilateral thyroidectomy 462d. Subset of cats showed mortality within a year from other causes.

[/quote]

Tim

Re: Hyperthyroid surgery

joanne mcallister — Thu, 13 Feb 2014 11:37:25 GMT

Usually the parathyroid tissue is obvious (especially cranially) and easy to dissect off the surface of the thyroid. If I can do this and preserve the blood supply I will leave in situ, otherwise I dissect out completely and place in a pocket created by incising a small hole in strap muscle and suture muscle closed over it. Apparently it revascularises. If I am not able to identify and preserve the parathyroid on removing the first gland, I am much more cautious about offering surgery for the second.

Re: Hyperthyroid surgery

David Mills — Wed, 12 Feb 2014 22:14:09 GMT

For those that are interested, I'll be presenting an abstract at BSAVA this year on this very subject.

101 cats assessed, recurred in 40%, with median time to recurrence after unilateral thyroidectomy 462d. Subset of cats showed mortality within a year from other causes.

Re: Hyperthyroid surgery

Ian Ross — Wed, 12 Feb 2014 14:38:02 GMT

My own cat had a unilateral hyperthyroid problem at 7 years or so old, operated, and was fine for about 3 months, then other side developed enlargement, operated and has been fine for 6+ years since.

Mostly I see them developing a bilateral disease after a year + but obviously a vet's cat wanted to be different

Ian

Re: Hyperthyroid surgery

Rob Loxley — Tue, 11 Feb 2014 18:02:22 GMT

[quote user="Martin Atkinson"]Can you honestly say that you can reliably identify the parathyroid tissue[/quote]

I'd say most times

[quote user="Martin Atkinson"] preserved a blood supply every time[/quote]

No, but I'd aim to do a modified extracapsular and view reimplanting the PT as a bit of a salvage if that hasn't worked. With bilateral presentations I'll only do bilateral single-procedure if I'm happy with the first side, else stage it (and I'm aware of the data comparing single surgery and stage bilateral)

Re: Hyperthyroid surgery

Martin Atkinson — Tue, 11 Feb 2014 17:22:34 GMT

[quote user="joanne mcallister"]

I usually dissect parathyroid tissue away from the thyroid before extracapsular removal and embed it in a pocket within strap muscle. I find I can then safely remove the second thyroid 6 weeks after this if I need to without any problems re: hypocalcaemia

[/quote] Can you honestly say that you can reliably identify the parathyroid tissue and be confident you have preserved a blood supply every time Joanne?I think I'm a pretty good soft tissue surgeon and would say that it is pretty damn difficult to do this.

Re: Hyperthyroid surgery

joanne mcallister — Tue, 11 Feb 2014 14:05:16 GMT

Re: Hyperthyroid surgery

Martin Atkinson — Tue, 11 Feb 2014 09:51:46 GMT

I encourage clients to go for unilateral thyroidectomy if I can only feel one goitre. IME the contralateral gland rarely becomes hyperplastic in less than 18 months. I have performed several bilateral thyroidectomies but with the best will in the world it is nigh on impossible to be certain you've not damaged the parathyroids and I've had 2-3 that have remained permanently hypocalcaemic. So I explain the risk - that it is a damn site harder to monitor and treat hypocalcaemia than hyperthroidism medically and most clients elect to stay on medication. In the years BF (before Felimazole) I did 90% thyroidectomies/10% medical therapy (with the odd referral for radio-iodine) now it is the reverse.

I presently have one cat with bilateral goitres, the owner can't pill it, it won't eat Y/D, the transdermal gel won't get the T4 below 190 even on the maximum amount the owner believes she can apply practically and the last cat she had with a bilateral thyroidectomy was one of the ones that went hypocalcaemic so she's not keen on surgery. Guess what? It is going for radio-iodine therapy.

Re: Hyperthyroid surgery

Hannah Wynne Richards — Tue, 11 Feb 2014 09:21:31 GMT

If I couldn't do Cas then I'd play safe, take out the larger thyroid ( intracapsularly ) and hope that solves the problem. If it recurs think about either removing the other or seeing if they can pill it later.

I've once or twice found that hospitalising the cat, or sending it to a good cattery for a couple of weeks,can work wonders. It gets used to daily pilling, the medication makes it less hyperactive,and the owners find it much more amenable when it goes home.

Wynne

Re: Hyperthyroid surgery

Rob Loxley — Mon, 10 Feb 2014 23:18:42 GMT

[quote user="Kirsten Simpson"]Is this cat a feasible candidate for bilateral thyroidectomy straight off the bat[/quote]

Potentially, but I'd want to be happy about his renal function: any azotaemia; what's the SG? Has he a bilateral goitre?

[quote user="Kirsten Simpson"] if we cant check his Ca levels afterwards without sedating him?[/quote]

What's your plan if he goes hypocalcaemic...

Re: Hyperthyroid surgery

Robin Grimmer — Mon, 10 Feb 2014 09:43:54 GMT

I use the modified intra capsular technique - open up capsule, use sterile cotton bud to remove thyroid tissue and haven't had any problems with Ca afterwards when I've done bilateral thyroidectomy.

Re: Hyperthyroid surgery

Kirsten Simpson — Mon, 10 Feb 2014 09:18:19 GMT

Hello! Hijacking this thread to see if anything has changed dramatically in the last 2 years? Plus I haven't done a thyroidectomy since living down south (around 5+ years ago?!).

Lovely cat. Main presenting problem is weight loss and U+ inappropriately. Ful bloods showed NAD apart from v.high T4. O doesn't want to tablet, or try Y/D (as other cat in house) and doesn't want I131 therapy (although cat is insured) but would like thyroidectomy. Back in the day I used to take out both if affected, either would just take one out and warn owner could recur. Also, this cat is lovely but needlye shy and was impossible to get blood off conscious so had to be sedated. Is this cat a feasible candidate for bilateral thyroidectomy straight off the bat if we cant check his Ca levels afterwards without sedating him? Hmmm.

Re: Hyperthyroid surgery

Rob Davis — Mon, 16 Jan 2012 14:19:09 GMT

[quote user="David Mills"]More safeguard than anticipation. Hypocalcaemia can be catastrophic; hypercalcaemia isn't. Stop after 7d post op. A much better, economically, and for the cat, than stabbing it every 6h for a total calcium (whatever that means - istats ruinously expensive). Aware it isn't ideal medicine but at the same time we view it as safe. Possibly analogous to abx periopertively for orthopaedic ops? [/quote]

I can see the logic, but I have only had one cat go hypoglycaemic following surgery (typically it was a friend's cat), and frequently do bilaterals. I tend to keep in for 48 hours with BID blood calcium checks, and unilateral cases I send home the same day (unless they've previously had the other side done).

Re: Hyperthyroid surgery

David Mills — Sat, 14 Jan 2012 00:50:20 GMT

[quote user="robloxley"]

So is the argument to treat all in anticipation of hypocalcaemia? Isn't anticipating widespread postoperative hypocalcaemia saying something about the surgery?

[/quote]

More safeguard than anticipation. Hypocalcaemia can be catastrophic; hypercalcaemia isn't. Stop after 7d post op. A much better, economically, and for the cat, than stabbing it every 6h for a total calcium (whatever that means - istats ruinously expensive). Aware it isn't ideal medicine but at the same time we view it as safe. Possibly analogous to abx periopertively for orthopaedic ops?

[quote user="robloxley"]

As a further, home many are doing the 'vanilla' rather than 'modified' intra or extracapsular surgery?

[/quote]

Pray what does that mean? We do intracapsular sterile cotton bud etc.

Re: Hyperthyroid surgery

Braden Collins — Sat, 14 Jan 2012 00:47:06 GMT

I will normally do one side, warning the owners of possible recurrence if the other side develops a problem. Saves having to get too worried about calcium levels with parathyroid gland damage.

Re: Hyperthyroid surgery

Rob Loxley — Fri, 13 Jan 2012 23:48:22 GMT

[quote user="Evelyn Barbour-Hill"]what does AT10 stand for?[/quote]

It's a brand name for dihydrotachysterol (vitD). So is the argument to treat all in anticipation of hypocalcaemia? Isn't anticipating widespread postoperative hypocalcaemia saying something about the surgery?

Another keen thyroid surgeon here. Often we do unilateral surgeries and a fair few develop contralateral disease down the line. I've also seen some recurrences after bilateral surgery (though equally have had recurrence after I-131). On pure economics, it's a great value surgery compared to medical treatment and good monitoring.

As a further, home many are doing the 'vanilla' rather than 'modified' intra or extracapsular surgery?

Re: Hyperthyroid surgery

Evelyn Barbour-Hill — Fri, 13 Jan 2012 23:20:17 GMT

[quote user="David Mills"]We also tend to shift the cats out early on AT10[/quote]

Pardon my naiveté but what does AT10 stand for?

Re: Hyperthyroid surgery

Neil Wheadon — Fri, 13 Jan 2012 21:12:34 GMT

[quote user="David Mills"]

[quote user="Judith Joyce"]

I write as a surgeon but I struggle to understand the reluctance to operate most of these cases. The surgery is technically straight forward and takes less time than a cat spey. Clinical improvement is seen very quickly compared with other treatment options - most of the cats are clinically cured without further ado and most live long enough to die of something else. Furthermore, in most cases a single surgery is curative and in the relatively few cases which develop a contralateral recurrence a second surgery is not out of the question - even two ops is, in my experience, cheaper and less hassle than the frequently imperfect control offered by medical management. Radio-iodine is attractive but the cost and incarceration are off-putting.

Malcolm N

[/quote]

Fourthed.

As a charity, we often opt for surgery very early on, and don't always/usually go for the 3-4 weeks 'stabilisation' first. We also tend to shift the cats out early on AT10 only and aren't too concerned with the post-op calcium levels (not at all in unilateral) past 24hr.

Out of interest, this afternoon I had a look through our last 20 unilateral thyroidectomies - only 9 have recurred 4 years on, and none recurred before 2.5y. Just goes to show the data available in GP practice...

[/quote]

What a fantastic reply - thankyou

I'll operate, remove the enlarged side and can now give the owner an informed opinion of liklihood of recurrance.

Neil

PS If I had a hyperthyroid cat, I'd operate

Re: Hyperthyroid surgery

David Mills — Fri, 13 Jan 2012 20:49:51 GMT

[quote user="Judith Joyce"]

Malcolm N

[/quote]

Fourthed.

Re: Hyperthyroid surgery

Utlendigur — Fri, 13 Jan 2012 20:46:48 GMT

Fourthed

But saying that we do have quite a lot of cases on medication because we tend to get quite a few presented late - some owners wait until they have HCM, dyspnoea etc . Also those where we're worried about the possibility of renal insufficiency, or just very geriatric cats.

Re: Hyperthyroid surgery

Julian Earl — Fri, 13 Jan 2012 19:30:30 GMT

[quote user="Rob Davis"]

[quote user="Judith Joyce"]

Malcolm N

[/quote]

Speaking as a considerably less accomplished and knowledgable surgeon, I agree entirely. Thyroidectomy is not a difficult procedure (including bilateral) and should be within the capability of most GP surgeons. I find them really satisfyling cases as the improvement post op is generally dramatic and as long as case selection is sensible, there are very few complications.

[/quote]

Thirded.

To me, medication is making a simple condition complicated. I am totally unconvinced by the thoracic tissue argument posited by Intervet.

Re. your comment above Rob: I picked up the "find it, remove it" suggestion from CPD somewhere and it does seem to be rational, certainly for any long-standing case. Maybe I'm removing 2nd glands unnecessarily, I don't honestly know. If I found a very small contralateral gland then I possibly/probably would leave it but finding a gland anything bigger than (hmmm, thinks)... 7x3mm dimensions would make me suspicious of the condition being bilateral.

Re: Hyperthyroid surgery

Rob Davis — Fri, 13 Jan 2012 19:15:44 GMT

[quote user="Judith Joyce"]

Malcolm N

[/quote]

Re: Hyperthyroid surgery

Judith Joyce — Fri, 13 Jan 2012 19:01:22 GMT

Malcolm N

Re: Hyperthyroid surgery

James Laidlaw — Fri, 13 Jan 2012 17:06:59 GMT

I seem to recall that following unilateral surgery the contralateral gland will often (always, sometimes??? I don't know) become hyperthyroid within 1-2 years which fits with the 18 month estimate you have (possibly from BSAVA manual as well). I have tried to stick to medication and monitoring or I131 treatment, which works brilliantly in the few cases I have referred, provided you can convince the owner to spend in the order of £900-1500 and have their animal away from them for a minimum of 2 weeks, sometimes longer.

James