Page 142 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 10 · Surger y of the thyroid and parathyroid glands
Chapter 10 · Surgery of the thyroid and parathyroid glands

➜ OPERATIVE TECHNIQUE 10.2 CONTINUED
VetBooks.ir ASSISTANT

Not necessary if good self-retaining retractors are available.

ADDITIONAL INSTRUMENTS
Very fine forceps; fine scissors (e.g. Stevens tenotomy scissors); small self-retaining retractors (Gelpi, sternomastoid);
sterile cotton-tipped applicators can be helpful for fine dissection; bipolar diathermy. It is essential to have in-house
serum calcium measurement.

SURGICAL TECHNIQUE
Approach
Palpate the neck to confirm clinical findings of enlarged thyroid glands in the conscious patient. Make a midline skin
incision at about the level of the palpated glands, extending from the caudal edge of the larynx down to the manubrium.
Surgical manipulations
1 Continue the dissection in the midline, separating the sternohyoid and sternothyroid muscles. Place retractors to
hold the muscles apart.
2 Expose the ventral trachea and identify the thyroid glands on the lateral and ventral aspects of the trachea. Identify
and avoid the caudal laryngeal nerves. Inspect both glands carefully to identify disease as well as to identify the
parathyroid glands and the pattern of vascularization in the individual patient. Note: If the contralateral gland is
normal, it should be atrophied; if the contralateral gland is a ‘normal’ size, then the cat probably has bilateral
disease.
3 Make a small, very superficial incision in the caudoventral gland and carefully peel away the thyroid gland from
the capsule.
4 Ligate the caudal vessels with very fine suture material or cauterize them.

5 Continue the dissection, meticulously removing all traces of thyroid tissue within the capsule.
6 Separate the capsule and remove it, but leave the part of the capsule underneath the cranial (extrathyroid)
parathyroid gland intact. It is also important to preserve the blood vessels entering the cranial aspect of the
thyroid gland capsule because this will maintain blood supply to the external parathyroid gland.
Closure
The site is observed closely for haemostasis prior to closure. The sternohyoid and sternothyroid muscles are
reapposed using a simple continuous suture. Most hyperthyroid cats are too thin to require subcutaneous tissue
closure and the skin is closed with a continuous subcuticular suture, or simple interrupted skin sutures.

POSTOPERATIVE CARE
Fluid therapy should be continued until the cat is eating and drinking normally. Signs of hypocalcaemia are usually seen
between 24 and 72 hours postoperatively and owners should expect a period of postoperative hospitalization, even
when there are no complications.

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