Page 154 - Manual of Equine Field Surgery

150 HEAD AND NECK SURGERIES

Cut ends of:

Ornohyoideus-ed

Sternothyroideus
Omohyoideus m.

Sternohyoideus mm.

Figure 25-8 Close-up view of the sternothyroideus

musculotendinous section showing dotted lines where

-c~t;.;:i;~ resection will occur. The omohyoideus muscle is being

Figure 25-6 Intraoperative view of sternohyoidec- retracted.

tomy, sternothyroidectomy, and omohyoidectomy for

DDSP.

Epiglottis Arytenoid cartilage

Ceratohyoideus m.
Cricoid cartilage

Ceratohyoid

Figure 25- 7 Lateral view of Lingual process bone

the larynx illustrating the inser- of basihyoid bone

tion of the sternothyroideus on ---~.,,....,:;

the thyroid cartilage. The omohy- Thyrohyoid

oideus muscle is being retracted. bone Thyrohyoid

membrane Retraction of

Insertion of the omohyoideus m.

sternothyroideus m.

ments to the sternohyoideus muscles. This proce- on the caudal edge of the thyroid cartilage to

dure is better performed with the patient under ensure that the correct structure is isolated. A spay

general anesthesia because of the more extensive hook may be used to help isolate and exteriorize

dissection, although it can be accomplished in the the tendon9 (Figure 25-7). A small vein often lies

standing patient. This procedure has the advan- adjacent to the tendon and should be avoided.

tage of removing all of the caudal retractors of the Forceps are placed across the muscular portion of

larynx. the sternothyroideus muscle. The tendon is tran-

sected, and a 2-cm portion of the muscle is

Sternothyroideus Tenectomy and Sternohyoideus removed (Figure 25-8). The omohyoideus is

Myectomy dissected from the sternohyoideus muscle, and a

Another variation of this procedure involves a 5-cm section of sternohyoideus is then removed

sternothyroideus tenectomy and sternohyoideus (see Figure 25-6).

myectomy, A 5-cm ventral mid-line skin incision

is made over the larynx and is extended caudally Staphylectomy

to the level of the first tracheal ring. The longitu- A ventral midline laryngotomy is performed at

dinal incision is extended through the paired ster- the level of the cricothyroid membrane. A 10-cm

nohyoideus muscles to expose the ventral aspect incision is made starting at the cranial border

of the larynx, the cricoid cartilage, and the crico- of the thyroid cartilage and extending caudal to

tracheal space. The musculotendinous portion of the first tracheal ring (Figures 25-9 and 25-10).

the sternothyroideus muscle is located at the level The incision is continued through the cutaneous

of the cricoid cartilage, about 3 to 4 cm off colli muscles and subcutaneous tissue. The paired

midline. The tendon is followed to its attachment sternohyoideus muscles are identified and sepa-