Authors : Emil Ofner, DVM
Marina Barižon, DVM
Mario Grubišić, DVM
Silvijo Tarasić, Eng; OLYMPUS d.o.o. Zagreb
Small Animal Veterinary Clinic More, Šibenik, Croatia
Key words : Brachycephalic syndrome, PlasmaKnife
Brachycephalic obstructive airway syndrome is chronic, repetitive and life threatening disorder and because of that it often requires immediate surgical intervention. In literature, there are many described surgical techniques to treat different aspects of brachycephalic syndrome. The soft palate and tonsil resection using Gyrus PlasmaKnife dissector is a novel technique which is in our opinion ideal for every veterinary practice.
Brachycephalic Obstructive Airway Syndrome (BOAS) is a complex chronic condition characterized by narrowing or collapse of the different airway passages. This disorder is hereditary and because of that associated with different breeds of dogs. Depending on general skull morphology dogs can have brachycephalic, mesaticephalic and dolichocephalic heads. Phenotypic selection in search for round heads and foreshortened nose in brachycephalic breeds of dogs resulted in loss of sagittal crest and a braincase longer than the facial bones. Rostral shortening of the skull in brachycephalic breeds, without paralell reduction in the associated soft tissues, results in disproportion causing abnormal airway resistance. These primary anatomic defects lead to secondary changes over time (Table 1). At the time of presentation, clinical sings can be mild, moderate or severe. All moderate and severe cases are accompanied with sleep difficulties, coughing, dyspnoea, gagging, retching and syncope. While moderate and severe cases need prompt surgical intervention only mild cases can be managed conservatively.
Patients and methods
Last decade, there is a huge increase of pure breed dogs and breed related disorders in Dalmatia. Brachycephalic breeds which have round heads resembled those of human infants are becoming very popular. Among breeds presented with BOAS in our clinic overrepresented breeds are Pugs, French Bulldogs and Cavalier King Charles Spaniels.
Most patients in time of presentation have serious and life threatening symptoms. Because of that diagnostic procedure needs to be done quickly with skilled team. In Veterinary Clinic More all patients with BOAS are put under general anesthesia, intubated and after radiographic examination, laryngo-tracheo-bronchoscopy procedure with or without rhinoscopy is done. After a complete examination of upper and lower respiratory pathways we prepare surgical planning. In almost all situations we do a soft palate resection. If needed, vertical or horizontal external nares resection, tonsillectomy or everted laryngeal saccules excision is done also.
To clearly and precisely visualize the surgical site is critical in all surgical procedures involved in BOAS. Because of that, all patients should be positioned in sternal recumbency with maxilla resting on the perch and the mandible should be suspended by rolled gauze ventrally (Picture 1 ). If soft palate resection is going to be done all tissues extending mid to the caudal aspect of tonsillar crypt should be excised. The soft palate is grasped with Allis clamps, pulled rostrally and dissected with PlasmaKnife dissector (Picture 2). If tonsils are enlarged in order to clear out as much space as possible we also do unilateral or bilateral tonsillectomy.
Though in available literature, there are lots of papers about soft palate dissection we didn’t find anything about using PlasmaKnife dissector for soft palate and tonsil resection. Traditionally resection is done with sharp dissection using Metzenbaum scissors or monopolar electrocautery. Other reported techniques include bipolar sealing devices (LigaSure), laser or harmonic scalpel. Surgery time for soft palate resection was about 12 minutes for sharp dissection, and about 5 minutes for laser surgery.
PlasmaKnife dissector is triode-tipped bipolar instrument (Picture 3) which attaches to the Gyrus G3 WorkStation generator (Picture 4). It uses PlasmaCision technology that enables both simultaneous and sequential hemostatic sealing and cutting. PlasmaCision leverages the electricaly conductive properties of tissue fluid to form a tightly defined low temperature plasma field over the active pole of the triode tip. The instrument has two main modes of operation, PlasmaCision cut phase and pure coagulation phase. In cut phase a low-temperature plasma field precisely divides tissue and coagulates blood vessels. In pure coagulation phase tip delivers controlled radio frequency energy for sealing larger blood vessels ( Pictures 5 and 6). Tip design has both convex and flat surfaces. The convex part for pin point accurate dissection and flat surface provides maximum tissue contact for effective hemostasis along with a suction channel for blood and vapor (Picture 7). Switching between modes is done by foot pedal.
Surgical time for soft palate resection with PlasmaKnife dissector was average 63 seconds and 44 seconds for unilateral tonsillectomy. Realized time was about 10 times faster in comparison to traditional sharp dissection and 5 times faster comparing to laser surgery. Production of smoke and vapors was minimal and suction channel was not needed. Postoperatively, all dogs received local dexamethasone to reduce swelling (Picture 8). We didn’t have any postoperative complications.
PlasmaKnife dissector in combination with Gyrus G3 WorkStation generator is multi – functional instrument and provides versatility, efficiency, clean incisions, and hemostatic performance with minimal tissue damage.
Again, we are thankful to Mr. Silvijo Tarasić and Olympus d.o.o. Zagreb who recognized our enthusiasm and provided technical expertise that greatly assisted us in implementing new technology improvements in our practice.