TECHNICIAN UPDATE

Not A Rhino; a Wry Nose

Surgically correcting a yearling's campylorrhinus lateralis

By Arie Wolff, LVT, LVMT

A Rocky Mountain Horse yearling suffering from wry nose presented to the Equine Surgery, Lameness, and Rehabilitation Service at the University of Tennessee, College of Veterinary Medicine in March 2022. The airflow of the yearling was restricted through the nasal cavity, with the right nasal passage especially affected. The premaxillary incisors failed to contact the mandibular incisors because the premaxillae, maxillae, nasal and vomer bones, and the nasal septum deviated to the left of the sagittal plane of the head. The deviation was determined radiographically to be about 30 degrees.

While standing, the horse received a temporary tracheostomy at the juncture of the proximal- and middle-thirds of the cervical portion of the trachea. After the horse was sedated with xylazine HCl, it was anesthetized with IV ketamine HCl and midazolam. With the horse in dorsal recumbency and still in the anesthetic induction room, a laryngotomy was performed at the cricothyroid space, and an endotracheal tube was inserted into the trachea through the temporary tracheostomy.

The yearling was then placed on the surgery table in right lateral recumbency with its head elevated by a sandbag. Anesthesia was maintained with isoflurane.

A 10-cm incision was made over the center of the 15th rib. The incision extended through the periosteum, which was reflected from underlying bone using a periosteal elevator. A 5-cm section of rib was harvested using obstetrical wire and placed in gauze swabs soaked in blood. The musculature and subcutaneous tissue were juxtaposed in one layer with 2-0 polydioxanone suture (PDS) placed in a simple-continuous pattern. The skin incision was closed with staples, and a stent bandage was sutured to the incision.

The patient prior to surgery.

All images are courtesy of Arie Wolff

Preoperative imaging.

At the same time a section of rib was being harvested, a 5-cm incision was made on the dorsal midline slightly rostral to the rostral border of the dorsal conchal sinuses, the site of which was determined radiographically using staples placed on the dorsal midline of the nose as markers. This incision extended to the ligament connecting the right and left nasal bones. A circular section of the nasal bones and underlying parietal cartilage was excised, on midline, using a 3/8-inch (1-cm) Galt trephine. Three, 1-m strands of obstetrical wire, the ends of which were ensheathed with a polypropylene catheter to protect the respiratory mucosa, were placed through the nasal cavity, using the trephine hole and the laryngotomy, so that they encircled the dorsal, ventral, and caudal aspects of the nasal septum. After the three loops of wire had been placed, the caudal, ventral, and dorsal borders of the septum were incised simultaneously, and the rostral border of the septum was transected using a scalpel, leaving about 1-cm of septum rostrally. The resected septum was extracted from the nasal cavity, and the nasal cavity was packed with rolled gauze. The skin incision was closed with staples, and the laryngotomy was left unsutured to heal by second intention.

To straighten the nasal bones, an 8-cm incision was made on the dorsal midline centered at the site at which the nasal bones deviated from the sagittal plane. Using an oscillating saw, a wedge of nasal bone, the point of which was at the concave border of the deviation, was excised from the right and left nasal bones, and the transected nasal bones were rotated to the sagittal plane. The repositioned left nasal bone was fixed to parent bone with an 8-hole, 2.7-mm, dynamic compression plate, and the repositioned right nasal bone was fixed to parent bone with a 12-hole, 2.7-mm, dynamic compression plate. The plates were attached using 6, 8, and 10-mm cortical screws. Subcutaneous tissue was closed with 2-0 PDS suture placed in a simple-continuous pattern, and the skin incision was closed with staples.

The airflow of the yearling was restricted through the nasal cavity, with the right nasal passage especially affected.

The horse was placed into dorsal recumbency with its mouth held open with a wooden wedge placed between the right cheek teeth. A 5-cm, mucoperiosteal incision, centered at the site of maximum of the deviation of the maxillae, was made on the ventral border of the premaxilla at each interdental space. Through these incisions, the premaxillae and palatine processes of the premaxillae were transected with an oscillating saw after elevating the overlying periosteum and gingiva. The transected segment of the upper jaw was rotated until the premaxillary and mandibular incisors were aligned. A 2-cm rib graft was inserted into the gap created at the left premaxilla using a mallet and dental punch. The transected segment of the upper jaw was stabilized to parent bone with 4 appropriately sized Steinmann pins (3 on the left side and 1 on the right side) inserted through the premaxillae into the medullary cavity of the ipsilateral maxillae. Dental acrylic was placed over the protruding ends of the pins to prevent the exposed end of the pins from abrading the mucosa of the upper lip. The incisions in the interdental space were closed with 2-0 barbed PDS suture placed in a simple-continuous pattern. The occlusal surface of the incisors was reduced with a power-driven float.

The horse was administered potassium penicillin gentamicin sulfate and phenylbutazone before surgery and for 5 days after surgery. The horse was administered omeprazole for 12 days after surgery. Hydromorphone was administered as needed for 2 days. Antimicrobial therapy was changed at 5 days post-surgery to trimethoprim-sulfamethoxazole, which was administered for 14 days. Intravenous administration of phenylbutazone was changed at 5 days to oral administration of a paste for 12 days.

The patient prior to anesthesia induction.

Nasal septum

Implants

Conclusion

Surgery time was 4 hours; anesthesia time was 4.5 hours. Recovery from anesthesia, which was assisted, was 1 hour. The gauze pack in the nasal cavity and the tracheostomy tube inserted into the trachea after surgery were removed 3 days post-surgery. The yearling was discharged 11 days after surgery.

Movement of air through the nasal cavity was good when the horse was presented 70 days after discharge for evaluation. One of the screws from the 12-hole, dynamic compression plate had backed out and was removed through a stab incision. Radiographs showed that the horse’s nose was still deviated but to a lesser degree. The owner believed that surgery had improved the horse’s appearance and quality of life. MeV

Teaching Points

Equine campylorrhinus lateralis, or wry nose, is a congenital deformity of the premaxillae, maxillae, nasal and vomer bones, and nasal septum. This facial deviation results in partial occlusion of the nasal cavity, which, if severe, can affect a foal’s ability to nurse. Most foals with wry nose, however, do nurse effectively.

Surgical correction of this deformity was first reported in the late 1970s and was performed in two stages. Stage 1 of the correction entailed osteotomy and repositioning of the maxillae to correct the malocclusion of the incisors. The repositioned upper jaw and a rib graft, inserted into the osteomy on the concave side of the deformity, were stabilized with internal fixation. The nasal septum was removed, and the nasal bones repositioned and stabilized with wire during a second surgery performed a few weeks later.

Similar techniques were used to correct the deviation of the horse described in this report, but correction was performed during one anesthetic period.

About the Author

Being in love with horses her whole life, Arie joined the University of Tennessee College of Veterinary Medicine as the Equine Surgery Technician in 2018. Working with horses and competing from a young age in Hunter/Jumper disciplines, her passion and focus have contributed to her knowledge and skills in the welfare and care of horses. When Arie is not working or competing, she spends her time advancing her yoga practice and hiking with her partner, Jarret, and their dogs, Stryker and Riley. Arie holds a bachelor's degree in animal science and an associate's degree in Veterinary Technology Medicine. She is a licensed technician in the states of Tennessee and New York.

For more information:

Schumacher J, Brink P, Easley J et al. Surgical correction of wry nose in four horses. Vet Surg. 2008;37:142-148.

Cousty M, Haudiquet P, Geffroy O. Use of an external fixator to correct a wry nose in a yearling. Equine Vet Educ. 2010;22:458-461

Robertson JT. Surgical correction of wry nose in newborn foals. Equine Vet Educ. 2010;22:462-466

Valdez H, McMullan WC, Hobson HP, et al. (1978) Surgical correction of deviated nasal septum and premaxilla in a colt. J Am Vet Med Assoc. 1978;173:1001-1004.