34th Annual Scientific Meeting proceedings

Introduction

Rhinotomy is rarely indicated in dogs and cats, as many diseases pertaining the nose can be adequately diagnosed and treated using rhinoscopy.¹ However, surgery of the nose can be indicated for removal of nasal foreign bodies that cannot be removed using endoscopy, for treatment of selected intranasal neoplasia (as part of a combination therapy, e.g. radiotherapy before or after surgery), and for the treatment of chronic infectious rhinitis and/or sinusitis associated with nasal obstruction (especially in cats) or decreased drainage from the frontal sinus into the nasal cavity proper leading to empyema and subcutaneous abscessation.^1,2 Most surgeons prefer a dorsal approach to the nasal cavity and paranasal sinuses because of enhanced accessibility to the cribriform plate and frontal sinuses, but ventral rhinotomy may be indicated in selected patients with focal abnormalities in the ventral meatus or nasopharynx. A lateral approach to the nasal cavity provides access to the rostral part of the nose with great visibility of the nasal septum for instance for removal of rostral nasal septum carcinoma.³ Even with proper patient selection and thorough diagnostic work-up and preoperative evaluation of rhinologic patients, dorsal rhinotomy with unilateral or bilateral turbinectomy is a major surgical procedure with a number of possible complications^4,5, which will be discussed in this lecture.

Complications

Complications associated with dorsal rhinotomy include entrance into the cranial vault and hemorrhage during and after surgery (epistaxis). In addition, early postoperative complications include pneumocephalus and septic meningoencephalitis, subcutaneous emphysema, failure to mouth breathe, aspiration pneumonia, persistent anorexia, and pain. Persistent nasal discharge or respiratory noise and recurrence of disease are considered late postoperative complications.^1,4,6 Oronasal fistula formation has been reported after ventral rhinotomy only⁶, but chronic fistulisation after wound dehiscence and osteomyelitis or osteonecrosis is possible after dorsal rhinotomy in patients that have received radiation therapy before surgery.

Complications of Dorsal Rhinotomy

Hemorrhage⁴

The nasal bones, nasal cavity, nasal turbinates, and overlying mucosa receive an abundant blood supply from branches of the maxillary artery, including the sphenopalatine, ethmoid, greater palatine, dorsal, and lateral nasal and maxillary labial arteries. Standard dorsal midline rhinotomy causes mild hemorrhage of the incised periosteum and nasal bone. Disruption of the extensive arterial network within the nasal cavity during turbinectomy causes considerable hemorrhage. Nasal hemorrhage can be managed by quickly but carefully completing the turbinectomy and/or packing the nasal cavity temporarily with sterile gauzes under pressure for 5 minutes. Some bleeding can usually be controlled with direct electrocautery, using metal Frazier or Adson suction cannulae as conductor while “fixating” the end of the vessel with the tip of the suction tube and clearing the surgical area of blood at the same time. Excessive blood loss during dorsal rhinotomy can be prevented by having the procedure performed with speed, accuracy, and efficiency by a rhinologic surgeon with thorough knowledge of the regional anatomy and experience with the technique, ligation of the paired sphenopalatine arteries on the lateral floor of the nasal cavity and using electrocautery to seal other vessels during surgery. Temporary unilateral or bilateral occlusion of the common carotid artery has been reported to minimize hemorrhage during the procedure as well.⁷

Entrance into the cranial vault⁴

Inadvertent penetration into the cranial vault is possible during turbinectomy of the ethmoturbinates, especially when resecting tumors that have invaded the cribriform plate. Entrance into the cranial vault is prevented by having thorough knowledge of the regional anatomy, preoperative computed tomographic evaluation of the nose to assess tumor invasion into and erosion of the cribriform plate and using endoscopy assisted techniques for removal of the caudal turbinates.

Subcutaneous emphysema⁴

Subcutaneous emphysema is caused by the flow of air from the nasal cavity into the subcutaneous tissues around the rhinotomy site. It may be precipitated by violent episodes of sneezing, rostral obstruction to nasal airflow (nasal packing, blood clots, or inadequate removal of rostral nasal turbinates) and/or inadequate closure of nasal bone periosteum over the defect. Subcutaneous emphysema is usually self-limiting and resolves without treatment in 10 to 14 days. If desired, a small stab incision can be made and kept open with a Penrose drain to provide an outlet for accumulating air. Subcutaneous emphysema could potentially be a route for spread of infection; hence, treatment with broad-spectrum antibiotics is advised. Subcutaneous emphysema is prevented by ensuring to maintain normal nasal airflow. Endoscopic evaluation of the rostral nasal passages during the surgical procedure is very helpful to ensure all rostral turbinates have been removed.

Persistent nasal discharge or respiratory noise and recurrence of disease^1,4

Nasal airflow should improve after dorsal rhinotomy and nasal stridor should be minimal, but some degree of serosanguineous nasal discharge is expected to persist in all patients as a result of turbinate damage, inflammation, turbulent airflow, and loss of normal defense mechanisms. Dorsal rhinotomy alone for nasal neoplasia will neither cure the disease nor increase life expectancy. However, nasal airflow should improve temporarily after surgery. Some degree of nasal stridor and serosanguineous nasal discharge is expected to persist because of residual inflammation or remaining tumor growth or because of tumor recurrence. Wound dehiscence, wound infection, and fistula formation as a result of radiation induced delayed wound healing or (nasal) bone necrosis can occur when dorsal rhinotomy for cytoreductive surgery is performed after radiation therapy. Chronic nasal infections caused by turbinate removal and loss of normal defense mechanisms are usually controlled but not cured by long-term antibiotic therapy. Choice of antibiotic should be based on results of culture and sensitivity tests. In addition, in most animals, corticosteroids are indicated to suppress turbinate mucosal swelling and inflammation, especially in cases with allergy, hypersensitivity–based, or chronic nonspecific rhinitis. Wound dehiscence and infection are treated with proper wound management and systemic antibiotics until viability of tissues can be properly assessed and a healthy recipient bed has formed. Reconstruction and closure of the defect with local or axial pattern flaps can subsequently be performed. As the nasal cavity will never be anatomically or functionally normal after turbinectomy, proper client education is essential. In most cases of persistent rhinitis the clinical signs can be controlled with medical treatment directed at the primary cause of the rhinitis. Endoscopy assisted turbinectomy will lead to a more complete removal of neoplastic disease and therefore possibly longer disease (obstruction) free interval. Prevention of complications associated with radiotherapy is probably best achieved by instituting radiotherapy after complete surgical recovery of the patient and perform surgery well after radiation-induced dermatitis and osteomyelitis have subsided.

Complications of Ventral Rhinotomy

The indications for ventral rhinotomy are similar as those for dorsal rhinotomy. Whether or not a dorsal or ventral approach is preferred depends on the exact location of the pathology.^1,2,5 A ventral approach to the nasal cavity is the most cosmetic approach and can be used to more thoroughly explore the region caudal to the ethmoid turbinates, the ventral aspect of the turbinates and the rostral nasopharynx. Evaluation and evacuation of the frontal sinuses are limited though to the rostral half. The potential advantages of a ventral approach include a more rapid recovery, a more cosmetic closure, a lower risk of subcutaneous emphysema, and less postoperative pain⁶. Oronasal fistula formation has been reported as a complication of the ventral approach, but other complications are similar as for dorsal rhinotomy⁶. In young animals, midline ventral rhinotomy may alter muzzle growth⁸ and reduce transverse, but not sagittal, palatal length.⁹ Ventral rhinotomy is therefore not recommended in growing animals. Oronasal fistula formation can usually be prevented by adhering to a meticulous technique with careful delicate tissue handling, use of stay sutures and adequate tension-free appositional closure techniques ensuring viability of the blood supply to the edges of the incision. Repeated procedures through the same approach carry a much higher risk of oronasal fistula formation and should be avoided as well as performing surgery in a recently irradiated area.

Complications of Lateral Rhinotomy

A lateral approach to the nose is rarely performed¹⁰. Limited lateral rhinotomies have been described in combination with maxillectomy for tumor removal¹⁰ and for recovery of laterally displaced teeth. For the latter indication, an alveolar mucosal approach is described, where an incision is made through the alveolar mucosa from the nasal bone to the rostral end of the interincisive suture.¹¹ After reflection of the alveolar mucosa the dorsal and ventral lateral nasal cartilages can be reflected medially and the nasal mucosa incised to expose the nasal cavity. A proper lateral rhinotomy was described by Hedlund¹², which gives access to the nasal vestibule and rostral nasal cavity. When combined with elevation of the central planum as described by Pavletic, the approach allows access to the entire rostral nasal septum for removal of septal tumours such as squamous cell carcinoma.³ A slight ventral depression of the nasal bridge from lack of cartilaginous support is often noted after the latter procedure, but this stabilizes with the formation of fibrous tissue over time. Temporary dryness of the ipsilateral nasal planum is often noted as well. Recurrence of disease (squamous cell carcinoma) was reported in 40% of the cases where tumour free margins could not be achieved using this cosmetic technique, highlighting the need to select the patients for this technique carefully.

References

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4. Ter Haar G. Dorsal Rhinotomy. In: Griffon D and Hamaide A., editors. Complications in Small Animal Surgery 2016, Wiley-Blackwell; p. 137–43.
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11. NH P, Pope E, Cohn L, Constantinescu G. Alveolar mucosal approach to the canine nasal cavity. J Am Anim Hosp Assoc. 2001 Mar;37(2):179–82.
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