Soft palate and tonsil resection using PlasmaKnife dissector in dogs with brachycephalic obstructive airway syndrome – A novel technique


Dr Emil Ofner

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

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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.


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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.

Through the scope balloon dilatation of post-traumatic esophageal stricture in dog – case report


Author Emil Ofner

Emil Ofner DVM, Only sky’s the limit

Emil Ofner DVM, Veterinary Clinic More

Authors : Emil Ofner, DVM
Davor Crnogaća, DVM
Ivica Ukić, DVM
Silvijo Tarasić, Eng; OLYMPUS d.o.o. Zagreb

Small Animal Veterinary Clinic More, Šibenik, Croatia
Key words : esophageal stricture, balloon dilatation, regurgitation

Abstract :

Many diseases can cause esophageal stricture formation. Strictures in dogs are most frequently caused by foreign objects trapped in esophagus. The easiest way to diagnose and treat esophageal strictures is with flexible gastroscopes. Although there are lots of ways to dilate stricture, through the scope method, using esophageal balloon catheter is simple and safe method enabling direct visualisation of whole procedure.

Introduction :

Table 1

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Post-traumatic esophageal strictures in small animals are relatively rare problems. Most common cause of post – traumatic esophageal strictures is foreign body entrapment in the esophagus. Also, post – traumatic endoluminal strictures can be caused by caustic material ingestion or as a complication of esophageal surgery. In all of these situations damage of esophageal wall layers causes local inflammation with production of fibrous connective tissue. Local fibrosis or scar formation causes reduction of esophageal diameter thus causing stricture. Common symptoms of esophageal strictures are : regurgitation, salivation, dysphagia and ptyalism. Treatment is usually dilatation with balloon catheters or different types of cylindrical tubes called bogies (Table 1).

Case presentation :

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Picture 1. Olympus BE – 6 esophageal balloon catheter and hand held saline pump

Female, 9 years old West Highland White Terrier was brought to our clinic because of chronic regurgitation that lasted for four weeks. Prior to this, dog ingested bones and vomited them after five days. She could drink water and take liquid food. Solid food was regurgitated immediately after ingestion. Rectal temperature was normal but she lost 0.84 kg of body weight. Complete blood count and biochemistry values were normal. Radiographic examination didn’t reveal any cause of regurgitation. At this point we decided to do a flexible endoscopy examination of esophagus, which revealed 4 mm diameter stricture in distal part of thoracic esophagus.

Management and Outcome :

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Picture 2. Esophageal stricture

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Picture 3. Through the scope method of introducing balloon catheter into stricture

Dog was put under general anesthesia and intubated. Olympus GIF Q10 flexible gastroscope with 2.8 mm working channel was introduced into esophagus. After this, Olympus SWIFT balloon catheter (model BE – 6 ) was introduced through the working channel into the stricture ( through the scope method ). To generate force for stricture dilatation, catheter was expanded using saline and hand held Swift pump, two times for duration of two minutes. Steroid ( tramcinolone 40 mg / ml ) diluted with saline 1 : 2 was injected submucosally in three places around the stricture ( Pictures 1 to 5 ). After procedure, we prescribed omeprazole ( 1 mg / kg PO q24h ) for 7 days. After three weeks whole procedure was repeated. On next check-up dog regained normal body weight and was eating solid food without any problems.

Discussion :

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Picture 4. Expanding balloon catheter with saline

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Picture 5. Triamcinolone application

From a biomechanical perspective, all types of dilators ( balloons and bougies ) generate two types of forces on esophageal wall, radial stretch force which is responsible for dilatation and unwanted longitudinal shear force which can cause esophageal perforation ( Table 1 ).
Through the scope balloon dilatation of esophageal strictures is an easy and relatively safe procedure. Stricture dilatation occurs because saline filled balloon transfers radial stretch force on esophageal wall. Complications like esophageal preforation rarely occur when using balloon catheters because of low longitudinal shear force. Mean shear force of balloon catheters is 1,44 N. Low shear force of balloon catheters is associated with significantly lower risk for perforation.
When using other types of dilators like bougies, in theory perforations are more likely to occur because of strong radial and shear forces.Bougies involve passing long rigid instrument ( rigid cylindrical tube ) through the stricture blindly or by endoscopic guidance. Advancing bougie through stricture generates radial force which causes dilatation of stricture, but it also generates strong shear force which can cause perforation. Mean shear force when using bougies is 16,92 N for Maloney type and 6,92 N for Savary – Gilliard bougie.
Steroid injection prior or after dilatation improves outcome because it’s decreasing scar formation and need for repeated dilatations. Most cases will need repeated procedure in three weeks. If the dog is eating normally after 3-4 weeks it probably wont need new dilatation procedure.
After procedure, anti-acids are prescribed to reduce potentially negative effect of gastric acid on new scar formation. Use of proton pump inhibitors like omeprazole is recommended because of better effect than H2 receptor antagonists ( ranitidine, famotidine ).

Acknowledgments :

We are thankful to Mr. Silvijo Tarasić and Olympus d.o.o. Zagreb who provided technical expertise that greatly assisted us in implementing new technology improvements in our practice.

References :
1. Adamama-Moraitou KK, Rallis TS, Prassinos NN, Galatos AD. Benign esophageal stricture in the dog and cat: A retrospective study of 20 cases. Can J Vet Res. 2002 Jan;66(1):55-9.
2. Leib MS, Dinnel H, Ward DL, Reimer ME, Towell TL, Monroe WE. Endoscopic balloon dilation of benign esophageal strictures in dogs and cats. J Vet Intern Med. 2001 Nov-Dec;15(6):547-52.
3. Harai BH, Johnson SE, Sherding RG. Endoscopically guided balloon dilatation of benign esophageal strictures in 6 cats and 7 dogs. J Vet Intern Med. 1995 Sep-Oct;9(5):332-5.
4. McLean GK, LeVeen RF. Shear stress in the performance of esophageal dilation: comparison of balloon dilation and bougienage Radiology. 1989 Sep;172(3 Pt 2):983-6.
5. ASGE Technology Committee, Siddiqui UD, Banerjee S, Barth B, Chauhan SS, Gottlieb KT, Konda V, Maple JT, Murad FM, Pfau PR, Pleskow DK, Tokar JL, Wang A, Rodriguez SA. Tools for endoscopic stricture dilation. Gastrointest Endosc. 2013 Sep;78(3):391-404. doi: 10.1016/j.gie.2013.04.170.