Sunday, June 30, 2013

Sunday's Interesting cases: Ventriculocordectomy (devocalisation) of a Beagle using the laryngotomy approach

Case 1. Devocalisation in a Beagle

"The Vet book makes it sound so easy," I said to Dr Daniel as I was preparing to operate on this rarely done surgery using the laryngotomy approach. "Pull out the vocal cords, cut it and suture the ends. There is a very small space to operate and after excising the vocal cords, the ends shrink and there is no possibility of suturing. I use electro-excision to control bleeding. But there is alway a lot of bleeding in this surgery."

Sometimes I wonder whether the author of the article in "Small Animal Surgery 4th Edition, Theresa Welch Fossum" has ever done this surgery in the dog and actually stitch up the ends of the excised vocal cords.

I have done this operation in racehorses with laryngeal paralysis  at the Singapore Turf Club when I was an equine vet. It was also a bloody surgery. 

For dogs, there is an oral approach which I don't do as there are complaints of ineffectiveness in many cases. For this Beagle, he was neutered but he still has a habit of barking the whole day long, disturbing the neighbours. It was either death by lethal injection or this surgery. I try to dissuade owners from doing it by training the dog but it is easier said than done.  After some weeks, the owner brought this dog in for the surgery.  In my 40 years in practice, I have had performed around 5 of such operations in the dog only in  cases of desperation by the dog owner. It is not a surgery I will do as it is deemed cruelty.

The operation is recorded to share my experience with other vets researching the internet for such cases.

Domitor + Ketamine at 80% of the calculated weight via the IV drip.* 
Dom = 0.45 ml + Ket = 0.56 ml IV at 80%.  5 years old,  14 kg bodyweight.
Atropine 1 ml IM after that. Isoflurane gas + O2 via a smaller endotracheal tube (size 6) so that it can be pushed to one side to access one of the vocal cords for excision. 
Maintenance dose as high as 3.5%.
*Dog went rigid and head extended after Dom + Ket were given via the IV drip. Duration of a few seconds. Atropine 1 ml IM given. No recurrences of excitement.

Electro surgery
Dog's head under a bottle, extended neck.
Electro-excise skin and midline of the sternohyoid muscles retracted
Midline of thyroid cartilage electro-incised
Endotracheal tube could be seen taking up 50% of larynx
Assistant retracts thryoid cartilage so that the vocal fold can be seen. As space is so small, it takes experience to see the depression in which the vocal folds reside. View cranially. In the depression, use forceps to pinch out one tip of the vocal fold. Another forceps clamp below. Pull out as much as possible. I used the electro-incision to cut off the fold above the forceps and below the forceps whenever possible.

No stitching of the mucosa of the cut off vocal folds as stated in the Vet book as there is not much space to manipulate. This was not done by me in all my cases.

Lots of bleeding from the surgical areas. Unable to stem the bleeding as it was not possible to locate the bleeders. The less vocal fold area has lesser bleeding. This profuse bleeding has been present in all the past cases including the horse.

Stitch up thryoid cartilage, sternohyoid muscles and skin. Antisedan to wake up dog.       



No comments:

Post a Comment