Page 134 - Manual of Equine Field Surgery

130 HEAD AND NECK SURGERIES

from the underlying bone to provide access for the the depth of penetration during the trephination

trephine instrument. The skin edges are elevated procedure.

from the trephine site to avoid binding the soft

tissues in the instrument as it is turned. The trocar

point of the trephine should be extended to prop- ALTERNATIVE PROCEDURES

erly seat the saw blade. Once the saw blade is

seated, the trocar point should be retracted to Endoscopic examination using arthroscopic

minimize the risk of penetrating any underlying equipment allows visualization of the caudal

structures. Oscillating rotations are used to cut maxillary and frontal sinuses through a frontal

and ream out a circular plug of bone, with care sinus portal and of the sphenopalatine sinus

taken to control the instrument as the cut is through a caudal maxillary sinus portal.":" The

nearing completion to avoid damaging structures potential advantages of endoscopic examination

within the sinus. include the ability to obtain a more diagnostic

biopsy, the potential to treat minor problems, and

the ability to visualize a greater portion of the

POSTOPERATIVE CARE respective sinuses. Although many disorders of

the sinuses can be addressed by sinus trephination

Postoperative therapy depends 011 the primary with or without sinus endoscopy, several disor-

problem. Sinus trephination is principally used ders, such as resection or treatment of neoplastic

for diagnostic purposes and sint1s irrigation. With and nonneoplastic growths, may require a

the exception of primary sinusitis, most condi- sinus bone flap surgery to properly address the

tions will require further surgical therapy once the disorder."

primary problem is determined. Portals can

remain open for 10 to 12 days to allow repeated

irrigation or entrance. Mild cellulitis surrounding COMMENTS

the portal site often develops, which can be

managed by cleaning the site at least daily with Specific diseases of the sinuses include empyema,

moistened gauze sponges. sinusitis, tumors, and alveolar periostitis. Chronic,

unilateral purulent nasal discharge is the primary

sign associated with paranasal sinus empyema in

EXPECTED OUTCOME horses. Other clinical signs associated with disor-

ders of the sinuses include facial swelling and dis-

Even large trephine holes typically heal without tortion and ocular discharge.

complication in 3 to 4 weeks. Replacement bone

or fibrous tissue fills the defect. A small depression

is often palpable, but not visible, once the hair REFERENCES

grows out. The long-term prognosis depends on

the primary problem. 1. Merriam JG: Field sinusotomy in the management

of chronic sinusitis and alveolitis, Proc Am Assoc

Equine Pract 39:235, 1993.

COMPLICATIONS 2. Worster AA, Hackett RP: Equine sinus endoscopy

using a flexible endoscope: diagnosis and treatment

of sinus disease in the standing sedated horse, Proc
The most common complication is hemorrhage.

The sinus mucosa is extremely vascular, and this Am Assoc Equine Pract 45:128 1999.
3. Adams SB, Fessler JF: Sinus trephination. In Adams
vascularity is increased in inflammatory condi- SB, Fessler JF, editors: Atlas of equine surgery,

tions. Generally, direct pressure will control the Philadelphia, 2000, WB Saunders.

bleeding. Inadvertent penetration of structures 4. Ford TS: Standing surgery and procedures of the

within the sinus can result in additional compli- head, Vet Clin N Am Equine Pract 7:583, 1991.

cations such as oronasal fistula formation, bone 5. Schumacher J: Standing sinus surgery of the horse.

sequestration, hemorrhage, and death depending Proc ACVS Vet Symp 132, 2004.

on the structure penetrated. These severe compli- 6. Gerard MP: Applied paranasal sinus anatomy. Proc,

cations can be virtually eliminated by controlling ACVS Vet Symp 128, 2004.