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O serie de trei cazuri de sindrom respirator obstructiv la trei pisici si interventia de remediere a stenozei nazale cu flaps de avans / A case series of three cats with BOAS and surgical intervention for stenotic nares with single pedicle advancement flap

Rezumat

Ca in cazul cainilor, sindromul obstructiv respirator este prezent si in cazul pisicilor, cu o reprezentare mai mare in cazul anumitor rase. Spre deosebire de caini, tehnicile de remediere chirurgicala nu prezinta rezultatele scontate, cu o rata de recidiva crescuta sau cu o rata scazuta de satisfactie a proprietarilor pisicilor afectate. Anatomia zonala cat si partile afectate majoritar determina o redusa eficienta a tehnicilor chirurgicale dezvoltate pentru caini, in cazul pisicilor. In aceasta serie de cazuri am utilizat o tehnica prezentata de Chanel Barns in anul 2020, in cazul a cinci pisici. Tehnica se bazeaza pe excizia unei sectiuni din zona planseului narinelor si realizarea unui flaps de avans pentru inchiderea defectului, realizand astfel o deschidere imbunatatita pentru narine. Dintre cele trei pisici, doua au prezentat un aspect cosmetic, manifestari clinice imbunatatite si o buna satisfactie a proprietarilor iar uma a manifestat imbunatatiri temporare, revenirea semnelor clincie la cateva saptamani postoperator si o redusa satisfactie proprietarilor. Avand in vedere conformatia, faptul ca tesuturile locale au o elasticitate proprie si in functie de procesul de vindecare, recidivele sau necesitatea unor noi interventii reprezinta o realitate ce trebuie luata in calcul si nu exclusa.

Abstract

Like in the case of dogs, BOAS is diagnosed in the case of cats, with some breeds with a higher number of cases. Unlike dogs, surgical techniques do not result in optimal results, with a high rate of recurrence or with a low owner satisfaction. Local anatomy and the parts affected predominantly result in a low efficiency of the surgical techniques developed for dogs. In this case series I employed the technique published by Chanel Barns in 2020, in a case series of five cats. This technique is based on a single pedicle advancement flap resulting in a better opening of the nares. Out of the three cats with stenotic nares, two of them had cosmetic, functional improvement and good client satisfaction and one presented with low client satisfaction and growing to past respiratory signs weeks after surgery.

Introduction

BOAS is a well known syndrome in both dogs and cats [2, 3, 4]. For stenotic nares, specifically there are limited surgical techniques, better tailored for dogs then cats. In dogs, the main reason for stenotic nares is an enlarged structure of the alar wing. In dogs, stenotic nares received surgical treatment designed to reduce the width of the alar wing. This is not the best strategy in cats. Although some published work advocate the use of the same technique for cats as in dogs [5], this case series follows the technique published by Chanel Berns [1]. In his case series of five cats he uses a novel technique of a single pedicle advancement flap to treat stenotic nares in brachycephalic cats. Given the specifics of the anatomical differences at the origin of stenotic nares of cats I employed this technique in three male cats with BOAS. Follow up of the cats is for 2 weeks after surgery.

Material and method

Three cats were presented with obvious respiratory distress, stertor, reduced effort tolerance, scared facies, owner reporting low exercise, intermittent suffocation episodes, obvious stenotic nares. All males, two Scottish fold and one Persian. All cats underwent physical examination, CBC and serum biochemistry. All cats are under two years of age, one Scottish fold of 1.5 years, the other 1 year old and the Persian 2 years old. All cats received general anesthesia with butorphanol 0.4 mg/kg, medetomidine 10 mcg/kg, ketamine 4 mg/kg and maintenance with isoflurane 2.7 %.

Local area is shaved, aseptically prepared with isopropanol and iodine povidone. The surgical technique starts with a suture on the lateral aspect of the alar wing of both sides. Hemostatic clamps are used to pull on the sutures in order to open the nares. Two parallel incisions start from inside the nares on to outside, 45 degrees towards external of the philtrum. At the external end of the incisions both of the unite and the flap is elevated. The outside end part of the flap, 3 mm, are being excised with a rectangular incision. The pedicle is then sutured to cover the defect with 3/0, non-absorbable suture. The tractor suture is released and local area is aseptically treated with povidone iodine. Prophylactic antibiotic treatment is with amoxicillin/clavulanic acid combination 20 mg/kg, for 10 days, 2 bid. Elizabethan collar is placed to reduce the risk of self trauma.

Fig. 1. Stenotic nares in one cat
Fig. 2. Stenotic nares another cat of the case series
Fig. 3. Tractor sutures on the lateral aspect of the nares
Fig. 4. Elevated flap 45 degrees away from phyltrum
Fig. 5. Single pedicle advancement flap suture to enlarge stenotic nares.
Fig. 7. Postoperative aspect after single pedicle advancement flap for stenotic nares in BOAS of cats

Results

All cats had previous respiratory signs consecutive stenotic nares. After surgery, in the case of all cats had reduced or absent stertor, as a first sign. Two of the owners reported increased physical activity, increased effort tolerance and improved behavior. The owner of the third cat reported mild or progressively diminished improvement after surgery and by the time of suture removal reports of the owner matched the ones previous surgery. For the third male cat at the time of physical examination the opening of the nares is stenotic on both sides. For this one male cat the surgery did not offer long standing improvement.

Conclusion

In brachycephalic cats, the ventral skin fold may be a significant contributor to stenotic nares, unlike dogs. This is why the surgical techniques specifically designed for dogs may have little to no effect for cats. This new surgical technique is following anatomic specifics of brachycephalic cats. In this small case series two of the three cats showed both physical and owner reports of improvement. One male cat showed good physical improvement but owner reports mild to no benefit by the time of suture removal. For this cat the stenotic nares and respiratory symptoms reoccur and need another surgical procedure. This is a small case series, three cats, as the reference article of five cats and this technique still needs larger study review but shows good outcome and good surgical strategy, especially following anatomic specifics of BOAS of cats, different in the case of stenotic nares as for dogs. It is paramount client education towards the danger of recurrence after surgery and the need for different of another surgical procedure. As this brachycephalic cats have more then one anatomic malformations it is important to examine thoroughly and to communicate to the owner the risks and benefits prior to surgery.

De Dr. Daniel Lescai

Doctor in Medicina Veterinara

References

  1. Berns CN, Schmiedt CW, Dickerson VM, Murphy SM. Single pedicle advancement flap for treatment of feline stenotic nares: technique and results in five cases. J Feline Med Surg. 2020 Dec;22(12):1238-1242. doi: 10.1177/1098612X20910539. Epub 2020 Mar 16. PMID: 32175790.
  2. Dupré G, Heidenreich D. Brachycephalic Syndrome. Vet Clin North Am Small Anim Pract. 2016 Jul;46(4):691-707. doi: 10.1016/j.cvsm.2016.02.002. Epub 2016 Mar 21. PMID: 27012936.
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  5. Trostel CT, Frankel DJ. Punch resection alaplasty technique in dogs and cats with stenotic nares: 14 cases. J Am Anim Hosp Assoc. 2010 Jan-Feb;46(1):5-11. doi: 10.5326/0460005. PMID: 20045831.