NASAL TURBINATES (DORSAL)—CANINE

Indications

Exploratory rhinotomy for nasal neoplasia, infection, foreign body, and incisional biopsy.

Description of the Procedure

1. Lateral view of the canine skull showing regional anatomy and relationship between the nasal cavity, cribriform plate, and frontal sinus. The rostral aspect of the cribriform plate is caudal to a line parallel to the infraorbital margins (ventral orbital rims).

2. Dorsal view of the canine skull showing regional anatomy and relationship between the nasal cavity, cribriform plate, and frontal sinus. A line parallel to the palpable zygomatic processes of the frontal bone (dorsal orbital rims) indicates the rostral aspect of the frontal sinus. Intraoperatively, the frontomaxillary suture may be observed at the junction of the frontal sinus and nasal cavity. The cribriform plate is located medially and on the midline in relation to the palpable infraorbital margins.

3. The patient is positioned in ventral recumbency with the neck extended. The head is positioned over an elevated, padded area (rolled towel) and stabilized by taping the mandible to the operating table. A dorsal midline skin incision is made beginning at the rostral end of the nasal bone and extending caudally to a location parallel to the zygomatic processes of the frontal bone.

4. Subcutaneous tissues and periosteum are incised and reflected to expose the nasal bone and nasomaxillary, frontomaxillary, and frontonasal suture lines, which represent the articulations of the nasal, frontal and maxillary bones. Care should be taken to preserve the periosteum, which is an important tissue component of the closure. Rhinotomy is performed by using an intramedullary pin to make a nasal osteotomy on the midline rostral to a transverse line parallel to the infraorbital margins. The planned rectangular ostectomy site may extend caudodorsally to the frontonasal suture line if exploration of the frontal sinus is required.

5. Bone rongeurs are used to extend the circular osteotomy and expose ethmoidal conchae. In general, a narrow rectangular ostectomy is optimal, the width dictated by operative goals.

6. The frontal sinus may be visualized by caudodorsal extension of the ostectomy. The inner table of the frontal bone is removed allowing visualization of the frontal sinus ectoturbinates and mucosa.

Closure

The periosteum is apposed using synthetic absorbable suture in a simple continuous pattern. Subcutaneous tissues are apposed in a second layer followed by skin apposition using synthetic non-absorbable suture in a simple interrupted pattern.

Comments

Ostectomy for exploratory rhinotomy may be limited to either right or left nasal cavities for unilateral disease. Bone flaps may be used for rhinotomy instead of rectangular ostectomy. Fibrous and periosteal tissue healing provides a firm, cosmetic result in patients receiving ostectomy. Infectious or neoplastic disease processes may involve the nasal and maxillary bones. Since exploratory rhinotomy is often performed to obtain tissue samples for definitive diagnosis, the author prefers not to replace the potentially diseased bone flap.

Complete turbinectomy (either uni- or bilateral) usually circumvents persistent hemorrhage following rhinotomy for turbinectomy. Cotton umbilical tape placed through the nostril(s), packed in the nasal cavity, and maintained for 24 hours will provide hemostasis. A 5 Fr feeding tube placed through one nostril and into the nasopharynx for oxygen administration will aid in prevention of postoperative complications related to hypoxia.

APPROACH TO THE NASAL TURBINATES—FELINE

Indications

Exploratory rhinotomy for nasal neoplasia, infection, foreign body, and incisional biopsy.

Description of the Procedure

1. Lateral view of the feline skull showing regional anatomy and the relationship between the nasal cavity, cribriform plate, and frontal sinus. The rostral aspect of the cribriform plate is on a horizontal line midway between the infraorbital margins (ventral orbital rims) and the zygomatic process of the frontal bone (dorsal orbital rims).

2. Dorsal view of the feline skull showing regional anatomy and the relationship between the nasal cavity, cribriform plate, and frontal sinus. A line parallel to the medial curve of the palpable zygomatic processes of the frontal bone indicates the rostral aspect of the frontal sinus. Intraoperatively, the frontonasal suture may be observed rostral to the junction of the frontal sinus and nasal cavity. The cribriform plate is located medially and on the midline in relation to the palpable zygomatic processes of the frontal bone.

3. The patient is positioned in ventral recumbency with the neck extended. The head is positioned over an elevated, padded area (rolled towel) and stabilized by taping the mandible to the operating table. A dorsal midline skin incision is made beginning at the rostral end of the nasal bone and extending dorsocaudally to a location parallel to the zygomatic processes of the frontal bone.

4. Rhinotomy is performed for nasal cavity access and exposure of ethmoidal conchae similar to the procedure described for “Approach to the Nasal Turbinates (Dorsal)—Canine.” In general, a narrow rectangular ostectomy is optimal, the width dictated by operative goals. The frontonasal suture line may be used as a landmark for caudodorsal extension of the rhinotomy. Extension of the ostectomy caudodorsally to a line parallel to the medial curve of the palpable zygomatic processes of the frontal bone allows sinusotomy for exploration of one or both frontal sinuses.

Closure

The periosteum is apposed using synthetic absorbable suture in a simple continuous pattern. Subcutaneous tissues are apposed in a second layer followed by skin apposition using synthetic non-absorbable suture in a simple interrupted pattern.

Comments

Ostectomy for exploratory rhinotomy may be limited to either right or left nasal cavities for unilateral disease. The cribriform plate is well vascularized and should be avoided. Since it is not well visualized during surgery, the surgeon should be familiar with anatomic landmarks defining its location. Bone flaps may be used for rhinotomy instead of rectangular ostectomy. Fibrous and periosteal tissue healing provides a firm, cosmetic result in patients receiving ostectomy. Infectious or neoplastic disease processes may involve the nasal and maxillary bones. Since exploratory rhinotomy is often performed to obtain tissue samples for definitive diagnosis, the author prefers not to replace the potentially diseased bone flap.

APPROACH TO THE FRONTAL SINUSES—FELINE

Indications

Exploratory sinusotomy for neoplasia, infection, lavage and drainage, and incisional biopsy/microbial culture.

Description of the Procedure

1. The patient is positioned in ventral recumbency with the neck extended. The head is positioned over an elevated, padded area (rolled towel) and stabilized by taping the mandible to the operating table. A dorsal midline skin incision is made centered on a location that parallels the zygomatic processes of the frontal bone (dorsal orbital rims) and ending rostral to a location that parallels the medial canthi.

2. The periosteum is incised on the midline and reflected using a periosteal elevator to expose the paramidline frontal bone areas over the frontal sinus. A bone trephine may be used to perform the sinusotomy rostral to a location that parallels the zygomatic processes of the frontal bone. The sinusotomy may be enlarged using bone rongeurs to expose the caudal nasal passages for sinus drainage or greater areas of frontal sinus for sinus obliteration.

Closure

The periosteum is apposed using synthetic absorbable suture in a simple continuous pattern. Subcutaneous tissues are apposed in a second layer followed by skin apposition using synthetic non-absorbable suture in a simple interrupted pattern.

Comments

Bone flaps are not necessary. Fibrous and periosteal tissue healing provides a firm, cosmetic result in patients receiving ostectomy for sinusotomy. An intramedullary pin may be used to perform nasal osteotomy instead of a bone trephine.

APPROACH TO THE FRONTAL SINUSES—CANINE

Indications

Exploratory sinusotomy for neoplasia, infection, lavage and drainage, and incisional biopsy/microbial culture

Description of the Procedure

1. The patient is positioned in ventral recumbency with the neck extended. The head is positioned over an elevated, padded area (rolled towel) and stabilized by taping the mandible to the operating table. A dorsal midline skin incision is made centered on a location that parallels the zygomatic processes of the frontal bone (dorsal orbital rims) and ending rostral to the medial canthi.

2. The periosteum is incised on the midline and reflected, using a periosteal elevator to expose paramidline frontal bone areas over the frontal sinus. An intramedullary pin may be used to perform the sinusotomy at a location that parallels the zygomatic processes of the frontal bone.

3. The sinusotomy may be enlarged using bone rongeurs to expose the caudal nasal passages for sinus drainage or greater areas of frontal sinus for sinus obliteration or reconstruction of the nasofrontal opening.

Closure

The periosteum is apposed using synthetic absorbable suture in a simple continuous pattern. Subcutaneous tissues are apposed in a second layer followed by skin apposition using synthetic non-absorbable suture in a simple interrupted pattern.

Comments

Bone flaps are not necessary. Fibrous and periosteal tissue healing provides a firm, cosmetic result in patients receiving ostectomy for sinusotomy. A bone trephine may be used to perform sinus osteotomy instead of an intramedullary pin. Normal drainage from the frontal sinus may be re-established by placement of tubes into the frontal sinuses and through the ventromedial area of the nasofrontal opening.