Nasopharyngeal stenosis in cats: a retrospective study of 21 cases comparing endoscopic and surgical treatment (2018-2022)

Abstract

Objectives: Feline nasopharyngeal stenosis (NPS) is an uncommon disease in cats. The aim of this study was to compare the outcome with endoscopic and surgical treatments.

Methods: In this retrospective study, medical records were searched for cases of NPS and cases were divided into three groups: endoscopic treatment (balloon dilation); surgical treatment; or no treatment. Data are presented as median and range. Success rates and length of post-procedure corticosteroid treatment were compared between the two treated groups.

Results: A total of 21 cases were included: 10 males and 11 females (median age 6.7 years, range 0.5-14.4). Clinical signs at the time of initial presentation included permanent stertor (19/21), increased respiratory efforts (9/21), nasal discharge (9/21) and cough/reverse sneezing (6/21) with a duration in the range of 3-60 months. Diagnosis was based on endoscopy (21 cases) and CT (19 cases). In total, 12 cases were treated with endoscopic balloon dilation; 11 cases demonstrated a complete resolution of clinical signs (two cats had two dilations) and one case showed incomplete improvement after one balloon dilation but was successfully treated surgically. Eight cats were treated surgically (including one cat that was originally treated with balloon dilation), including seven cases with complete resolution of clinical signs and one case with a rostral NPS that failed to respond. Two cats were not treated and are still alive more than 3 years after diagnosis. The success rate was not different between the endoscopic (11/12) and surgically treated cases (7/8) (P = 0.85). The outcome was considered excellent in most of the cases as 18/23 procedures were successful, at least until the medium term, and 15/18 treated cats had no clinical signs of minimal stertor at follow-up.

Conclusions and relevance: This preliminary study suggests that minimally invasive endoscopic treatment of NPS has a high success rate and should be attempted in all cases with perforate stenotic membranes. When not achievable, extended palatoplasty can be recommended as a good alternative.

Keywords: Nasopharyngeal stenosis; balloon dilation; endoscopy; palatoplasty.

Figure 1

Clinical grade evolution before and after the initial procedure and at the last follow-up for cases with available follow-up data. The vertical axis indicates the clinical grade, while the numbers associated with the dots indicate the number of animals for each grade at each time point. (a) B-group; the cat that underwent surgical treatment a few days after the initial balloon dilation attempt appears only in panel b; the cat with a clinical grade of 4 at the last follow-up died at that time from suspected nasopharyngeal lymphoproliferative disease. (b) S-group: the cat with a clinical grade of 3 at last follow-up had concurrent chronic rhinitis

Figure 2

Time from initial diagnosis to last follow-up and follow-up details for treated patients with available follow-up data. The horizontal axis represents time in days. Each symbol on the timeline represents an individual patient at its last follow-up after initial treatment of nasopharyngeal stenosis; cats with relapse after balloon dilation (BD) are shown by the letter R with time to relapse indicated in brackets and time from initial BD to recurrence is indicated; for cats identified with the cross (†), the time of the last follow-up corresponds with the time of death

Figure 3

Endoscopic evaluation follow-up 2 years after last treatment showed partial recurrence of nasopharyngeal stenosis in 1/2 cats that already underwent two balloon dilation (BD) procedures. A new BD was not performed, because of the absence of significant clinical signs