Page 89 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

BSA V A Manual of Canine and F eline Head, Neck and Thoracic Surger y
BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

➜ OPERATIVE TECHNIQUE 5.3 CONTINUED
VetBooks.ir Surgical manipulations

1
Use blunt or sharp dissection with a sponge or scissors to free the vertical canal to the level of the annular
cartilage. To dissect with a sponge, hold the proximal (dorsal) portion of the ear canal with Allis tissue forceps
and, with a gauze sponge, wipe downward along the canal (similar to vertical ear canal ablation). This will remove
all the fat and expose the muscular attachments, which can be transected with scissors or cautery.
2 Continue to dissect carefully immediately adjacent to the canal, to the level of the skull, pausing intermittently to
palpate the area ventral to the canal to locate the facial nerve and identify the pulse of the external carotid artery.
Retract the soft tissues gently to facilitate exposure and dissection of the horizontal canal.
3 With Mayo or cartilage scissors, carefully transect the horizontal canal adjacent to the skull and osseous external
acoustic meatus, avoiding damage to the facial nerve, and remove the canal. Examine the margins of the osseous
external acoustic meatus to verify that all cartilage attachments have been removed.
4 With a periosteal elevator, gently expose the lateral surface of the bulla, and resect the ventral rim of the osseous
external acoustic meatus and the lateral wall of the bulla with a rongeur or burr.
5 Carefully curette the osseous tympanic bulla, remaining osseous canal, and rostral, caudal and medial aspects of
the lateral half of the tympanic cavity proper to remove any epithelium.
6 Gently flush the bulla with warm sterile saline and take samples of the area for culture before closure.

The pinna and lateral facial skin fter the skin has been incised the auricular cartilage The soft tissues are carefully dissected away from the
have been clipped and pre - is transected circumferentially around the vertical auricular cartilage.
pared. The ear is hung from canal opening ith curved ayo or cartilage scissors. aren . Tobias
a sterile towel clamp whilst aren . Tobias
drapes are placed.
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The facial nerve is visible along the ventrolateral Ring retractors improve exposure during soft The bulla has been opened to expose
surface of the annular cartilage. tissue dissection around the annular cartilage. debris and thickened lining hich ill be
aren . Tobias aren . Tobias removed with curettes, forceps or lavage.
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PRACTICAL TIP
Ring retractors may be helpful for improving exposure during deeper dissection

WARNING
The facial nerve can be damaged by vigorous dissection or retraction ventral or lateral
to the horizontal canal. The external carotid artery may be torn during lateral bulla
osteotomy if it is adherent to the bone or accidentally grasped with rongeurs

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