Traumatic Tracheal Avulsion in Cats: Diagnosis and Surgical Repair

Fig. 1: 6 mo. old DSH named Tigger

 Signalment and History

Tigger is a 6-month-old male neutered Domestic Short Hair cat who was presented for repair of a fractured left femur. (Fig. 1) Tigger had been hit by a car a few days before presentation. 

Physical Examination

On physical examination, the left rear leg was moderately swollen and crepitus was evident at the midshaft femur. The cat was also mildly dyspneic with tachypnea and mildly labored breathing. Thoracic auscultation was within normal limits. 

Diagnostic Evaluation

Thoracic radiographs showed pneumomediastinum and avulsion of the thoracic trachea with air-filled mediastinum seen bridging the gap. (Fig. 2) A mid-shaft oblique femoral fracture was also found. Tigger was transferred to the ICU for continuous monitoring and oxygen therapy if necessary. 

Fig. 2a: Lateral thoracic radiograph of Tigger showing the ruptured trachea 

and mediastinal "pseudo-airway." (white arrows)

                Fig. 2b: Ventro-dorsal thoracic radiograph of Tigger.

 

Anesthesia and Surgery

Tigger was sedated and an intravenous catheter was placed. The right side of his thorax was clipped and an initial cleansing of the surgical site was performed. Anesthesia was induced with propofol and an endotracheal carefully placed. The size of the endotracheal tube was smaller than indicated to avoid further injury to the trachea. Intermittent positive pressure ventilation (IPPV) was avoided to prevent disruption of the tenuous mediastinal connection between the ends of the ruptured trachea.

The right lateral thorax was prepared for aseptic surgery. A right lateral thoracotomy was performed at the 4^thintercostal space. A Buford rib retractor was placed and the cranial thorax was explored. Dissection of the trachea confirmed a complete avulsion of the trachea midway between the thoracic inlet and the carina. The mediastinum was serving as the only connection between the 2 ends of the ruptured trachea. 

The mediastinum was carefully dissected and the proximal trachea exposed. The endotracheal tube was found within the tracheal lumen, grabbed with thumb forceps, and pulled farther out. The tube was then inserted into the distal tracheal segment. IPPV was then begun and maintained for the duration of the anesthetic episode. The ends of the ruptured trachea were healthy; no debridement was necessary. The tracheal anastomosis was performed with 4-0 PDS in a simple interrupted pattern. The sutures were placed by grabbing 1-2 tracheal rings on each side of the anastomosis and were full-thickness bites from outside to inside, exiting the tracheal lumen. (Fig. 3) All sutures were pre-placed to allow accurate placement and then tied. (Fig. 4)

Fig. 3a: Surgical exposure of the trachea in Tigger after preplacing sutures across the gap. Note endotracheal tube (ET) within the tracheal lumen. 

Fig. 3b: Appearance of the trachea after completing the tracheal anastomosis.

Before closing the thorax, the endotracheal tube was gently pulled back and forth within the trachea to confirm that no sutures had penetrated the tube. A thoracic drain tube was placed and the thoracotomy closed routinely. The fractured femur was then repaired. Tigger recovered uneventfully from anesthesia. 

Postoperative Care

Tigger was returned to the ICU and given intravenous fluids and analgesics for pain. He did well overnight with stable vital signs and eupneic breathing. One day postoperatively Tigger was doing well with no dyspnea, normal vital signs, and a good appetite. Minimal amounts of air or fluid had been recovered through the thoracic drain tube so it was removed. Tigger continued to do well and was discharged from the hospital on the 2^nd day postoperatively with continued analgesic therapy and instructions to keep him indoors and restrict activity. 

Tigger returned for a recheck examination 1 month postoperatively. The referring veterinarian had removed skin sutures 2 weeks after surgery and the thoracic and leg incisions were well healed. On physical examination, Tigger was bright and alert with pink mucous membranes and normal auscultation of the heart and lungs. He was weight bearing on the left rear leg. Repeat thoracic radiographs were normal with only a slight indentation of the tracheal lumen at the site of repair. (Fig. 5) Radiographs of the left femur showed normal progression of healing at the fracture site. Tigger was discharged with instructions to continue rest and return in 4 weeks for repeat radiographs of the left femur to assess continued healing.

 

Discussion

 

Tracheal avulsion in cats is rare but has been reported. (1). It is likely the result of blunt trauma that causes the head and neck to be hyperextended which stretches the trachea leads to rupture. The site of rupture is usually the thoracic trachea midway between the thoracic inlet and the carina. The airway lumen is maintained by the mediastinum resulting in a so-called “pseudo airway”, allowing the cats to continue ventilating. In one study some cats presented up to 3 weeks after the traumatic episode. (1)

Cats with tracheal avulsion present for variable signs of dyspnea. Cats with delayed diagnosis may have trachea stenosis as fibrosis occurs at each end of the ruptured segments. Removal of the stenotic tracheal rings may be necessary to facilitate an adequate lumen at the anastomosis. (2)

The anesthetic protocol for these cats is designed around providing adequate oxygen flow and ventilation without causing iatrogenic disruption of the pseudo trachea. After induction, endotracheal intubation on Tigger was performed carefully without attempting to bridge the gap with the tube which could cause more injury. IPPV was avoided until the endotracheal tube was manipulated by the surgeon to provide a secure pathway for the delivery of oxygen. Immediately after thoracotomy, the first objective was to quickly pull the endotracheal tube from the proximal tracheal segment and place it in the distal segment to allow ventilation with oxygen and anesthetic gas. The trachea could then be carefully repaired. 

Based upon our experience with Tigger and a review of the reported cases, the prognosis for cats with tracheal avulsion is good after a successful repair. Most cats show adequate healing of the airway and can go on to live a normal life. 

 

References

1.     R N White, C A Burton. Surgical management of intrathoracic tracheal avulsion in cats: long-term results in 9 consecutive cases. Vet Surg, Sep-Oct 2000;29(5):430-5

2.     Fingland RB. Obstructive upper airway disorders. In: Saunders Manual of Small Animal Practice, 3d edition, Birchard SJ, Sherding RG, eds., Elsevier, 2006, pg. 1663-1664.

 

 

 

 

  

 

 

Nasopharyngeal Polyps in Cats: Key words - stertor, traction, and bulla osteotomy

Nasopharyngeal (NP) polyps in cats are characterized by well-circumscribed solid masses that are found in the nasopharynx, tympanic bulla, and Eustachian tube.  They are benign and thought to be secondary to inflammation from bacterial or viral infections.  Similar polyps can also be present in the external ear canal.  Affected cats are usually young (less than 1 year) but all ages can be affected.

Clinical Signs

Presenting signs of nasopharyngeal polyps may vary depending on location. Inspiratory stertor is commonly found due to the fleshy mass just dorsal to the soft palate causing obstruction of the nasal passages. Stertorous breathing in cats should alert the clinician to a mass lesion in the nasopharynx since other causes, such as elongated soft palate, are uncommon in cats.

Signs of otitis media, such as Horner’s syndrome, head tilt, and pain may also be seen. (Fig. 1) 

Fig. 1: Right sided Horner's syndrome seen in a kitten with a
NP polyp. 

Polyps in the external ear canal can result in or be secondary to otitis externa causing head shaking, ear scratching, and malodorous otic discharge.

Diagnosis

A thorough oral examination should be performed. Sedation will probably be necessary since the polyp will likely be obscured by the soft palate. If the mass is large enough simple palpation of the soft palate with a finger may indicate a mass effect. Retraction of the soft palate with stay sutures or a spay hook, with the cat in dorsal recumbency, should expose the mass. (Fig. 2)

Fig. 2: NP polyp in a cat (arrow) adjacent to the soft palate (SP) The cat is in
dorsal recumbency.

Otoscopic examination should also be performed to look for extensions of polyps into the external ear canal. Cleaning of otic discharge and debris may be necessary to adequately expose the mass.

Differential diagnoses for nasopharyngeal polyps are lymphosarcoma, other types of  neoplasia, foreign body, or congenital anomaly of the pharynx or upper airway. In one study of nasopharyngeal disorders in 53 cats 49% of them were diagnosed with lymphosarcoma and  28% were diagnosed as polyps.(1)

Imaging

Skull radiographs with emphasis on the tympanic bulla may provide useful information. Affected cats may show radiographic signs of chronic otitis media such as bony proliferation of the bulla and increased soft tissue density within the bulla.(Fig. 3)

Fig. 3: Bony proliferation of the bulla (arrow) secondary to
a nasopharyngeal polyp in a cat.

However, radiographs of the bullae are not a very sensitive imaging test and significant changes may be present with normal appearing bullae on films.

CT scans are a more sensitive and diagnostic imaging modality for bulla disorders and are useful in cats with nasopharyngeal polyps or other bulla diseases. Increased soft tissue density is commonly seen in one or both bullae. (Fig. 4)

Fig. 4: CT scan of a cat with a NP polyp showing increased soft tissue density
within the bulla. (arrow)

In cases of severe infection or invasive neoplasia, lysis of the bulla may be seen. These findings are useful for preoperative evaluation of cats undergoing ventral bulla osteotomy, a recommended surgery for cats with nasopharyngeal polyps or other chronic middle or external ear disease.

Treatment

Traction

Surgical removal of the polyps is the most effective means of relieving clinical signs. Under general anesthesia the cat is placed in dorsal recumbency and a mouth speculum placed to allow exposure of the oral cavity and pharynx. The soft palate is retracted rostrally with either stay sutures or a spay hook. Gentle manipulation of this tissue is important since it is sensitive and prone to edema with manipulation.  Even under anesthesia many cats will exhibit discomfort while the soft palate is being manipulated. Once the polyp is exposed, grasp it with either stay sutures or Allis tissue forceps.(Fig. 5) Gentle but firm rostral and ventral traction is placed on the polyp and continued until the mass is removed. 

Fig. 5: NP polyp (arrow) being removed by traction.

The tissue frequently has a large round component that is connected to a tail that is the Eustachian tube portion of the polyp. Control hemorrhage with direct pressure on the affected pharyngeal tissues.

Bulla Osteotomy

To completely remove the polyp tissues, ventral bulla osteotomy is then performed. Which side to operate depends on the preoperative imaging or lateralizing clinical signs. If lateralization was not possible or if changes are seen bilaterally on imaging, both bullae are ostetomized to be sure of removing all remaining polyp tissues. Although most polyps are unilateral, the author recently treated a cat with bilateral polyps requiring osteotomy of both bullae.

Small fragments of polyp tissue are usually found in the tympanic bullae exposed by the ventral bulla osteotomy. (Fig. 6-7)

Fig. 6: Diagram of a ventral bulla osteotomy in a cat. Rongeurs are used to
remove the ventral aspect of the bulla and expose both compartments.
from: Boothe H. Surgery for otitis media and otitis internal.
From: Saunders Manual of Small Animal Practice3rd ed., Birchard and Sherding, editors. Elsevier, 2006, pg. 601.

Fig. 7: Bulla osteotomy in a cat with NP polyps. The ventral floor of the
bulla has been removed. Note the polypoid tissue filling the bulla cavity. (arrow)

It is important to expose both compartments of the bulla when performing the osteotomy (ventral-medial and dorso-lateral chambers). Care is taken not to injure components of the inner ear, located dorsally in the bulla, when doing polyp excision and curretage.  Save all tissues removed for histopathology and obtain samples from the bulla for culture and sensitivity.

Postoperative Care and Complications

Routine supportive care including analgesics and antibiotics are administered postoperatively. Antibiotic choice is guided by results of culture and sensitivity of samples obtained from the bullae.

Common complications after polyp removal are pharyngeal swelling and Horner’s syndrome due to injury to sympathetic nerves in the middle ear. Both of these problems are usually mild, short term in duration, and not requiring treatment. Recurrence of polyps is more likely if only the nasopharyngeal portion is removed. In a clinical study of 31 cats with nasopharyngeal polyps, 5 recurred postoperatively, 4 of which did not have a bulla osteotomy. (2)

References

1. HS Allen, J Broussard, and K Noone (1999) Nasopharyngeal diseases in cats: a retrospective study of 53 cases (1991-1998). Journal of the American Animal Hospital Association: November/December 1999, Vol. 35, No. 6, pp. 457-461. 
2. Kapatkin, AS, Matthiesen, DT, Noone KE. et.al. Results of surgery and long-term follow-up in 31 cats with nasopharyngeal polyps. J Am An Hosp Assoc 1990 Vol 26 No 4 pp. 387-392.

Laryngeal Paralysis in Dogs: 5 things we've learned in the past decade

Laryngeal paralysis is a functional disorder of the larynx resulting in decreased abduction of the arytenoid cartilages during inspiration in dogs and cats. This causes airway obstruction, dyspnea and in some cases life threatening hypoxia. Clinical studies of various aspects of the disorder have improved our understanding of laryngeal paralysis. Key elements of some of these studies are listed and briefly described below.

Esophageal Dysfunction

Barium swallow in a dog with significant esophageal pathology

Idiopathic laryngeal paralysis is a disorder affecting more than just the larynx. Studies have conclusively shown that esophageal motility is abnormal in dogs with laryngeal paralysis.(1) This is a significant finding for many reasons, not the least of which is the relationship of esophageal dysfunction with aspiration pneumonia that commonly occurs after surgical correction by arytenoid lateralization. Dogs with esophageal or gastric disorders that predispose them to regurgitation can increase their chance of aspirating and developing pneumonia postoperatively.

When evaluating dogs with laryngeal paralysis, be sure to get a complete history with emphasis on the animal’s ability to prehend food and swallow normally.  Inquire about any regurgitation and vomiting. Obtain thoracic radiographs to evaluate for aspiration pneumonia and megaesophagus. If the dog appears to be a significant risk for aspiration, consider permanent tracheostomy as an alternative to arytenoid lateralization to reduce the risk of pneumonia. Metoclopramide can be administered to laryngeal paralysis dogs as a premedication to reduce the risk of regurgitation during general anesthesia. 

Polyneuropathy

More evidence that laryngeal paralysis is a complicated disorder affecting multiple organ systems are the studies showing its association with peripheral neuropathy.(2,3)  Several clinical investigations have documented generalized neuropathy in dogs that have laryngeal paralysis, emphasizing the need to thoroughly evaluate the neurologic status of these animals. Owners should be educated about this association, particularly in dogs that are not obviously affected by neuropathy when first presenting for their upper airway obstruction. Clinical signs of neurologic deficits may become evident sometime after treatment of the laryngeal paralysis.

Doxapram

An essential part of the diagnosis of laryngeal paralysis is the sedated laryngeal exam. Laryngeal function is assessed by watching the arytenoid cartilages abduct during inspiration. Since laryngeal function may be affected by the sedative drugs administered for the examination, a false positive result can occur if the sedation is excessive. Erratic respirations can also occur, complicating the assessment. Doxapram has been shown to assist in the exam by stimulating respiration allowing a more consistent and accurate evaluation of function.(4) The dosage of doxapram is: 1-5 mg/kg IV.

 Minimal Dissection Lateralization

The original surgical description of arytenoid lateralization included an extensive amount of dissection that is no longer felt to be necessary. After completely disarticulating the crico-arytenoid joint, i.e., the muscular process of the arytenoid from its articulation to the cricoid cartilage, the sesamoid band connecting the arytenoids' corniculate processes was also severed. This was a difficult step in the procedure because of poor exposure and in some cases resulted in perforation of the pharynx. 

Diagrammatic view of sharp incision of the inter-arytenoid sesamoid band.
This step in the surgical procedure is no longer considered necessary by many surgeons.
(reprinted from: Fingland RB. Obstructive Upper Airway Disorders. Saunders Manual of Small Animal Practice, 3rd ed., Birchard and Sherding editors,  Figure 161-6, Elsevier, 2006, pg. 1657)

Satisfactory lateralization is possible by simply incising the joint capsule of the crico-arytenoid articulation and leaving the sesamoid band in tact. Low suture tension has also been shown to be an effective means of opening the rima glottis compared to high suture tension.(5) I have used this “minimal dissection” technique for several years now. It provides for adequate arytenoid abduction, helps to prevent over-correction, and has lessened the incidence of aspiration pneumonia in my experience.

The “Tie-Back” is Not For All Dogs

Although the arytenoid lateralization procedure continues to provide satisfactory treatment for many dogs with laryngeal paralysis, it is contraindicated in dogs that are high risk for aspiration pneumonia. Owners need to realize that the lateralization procedure does not make the larynx normal. It opens the airway and relieves obstruction but the larynx is fixed in its position and not capable of closing. If the epiglottis cannot completely cover the laryngeal opening during swallowing, aspiration is likely to occur. Also, as  discussed previously, esophageal dysfunction or any other cause of chronic regurgitation or vomiting (megaesophagus, gastric disorder, etc.) increases the likelihood of aspiration. In these dogs a permanent tracheostomy should be considered to relieve the airway obstruction. 

A recently performed permanent tracheostomy in a dog.

For details on permanent tracheostomy in dogs, see 
http://drstephenbirchard.blogspot.com/2014/12/permanent-tracheostomy-in-dogs-life.html.

References

1. BJ. Stanley, JG Hauptman, MC Fritz, et. al.

Esophageal Dysfunction in Dogs with Idiopathic Laryngeal Paralysis: A Controlled Cohort Study. Veterinary Surgery Volume 39, Issue 2, pages 139–149.

2. Orla M. Mahony, Kim E. Knowles, Kyle G. Braund, et.al. Laryngeal Paralysis-Polyneuropathy Complex in Young Rottweilers. Journal of Veterinary Internal Medicine Volume 12, Issue 5, pages 330–337.

3. Braund KG, Shores A, Cochrane S, Forrester D, Kwiecien JM, Steiss JE. Laryngeal paralysis-polyneuropathy complex in young Dalmatians. American Journal of Veterinary Research 1994, 55(4):534-542.

4. Tobias KM1, Jackson AM, Harvey RC. Effects of doxapram HCl on laryngeal function of normal dogs and dogs with naturally occurring laryngeal paralysis. Vet Anaesth Analg. 2004 Oct;31(4):258-63.

5. S Bureau, E Monnet. Effects of Suture Tension and Surgical Approach During Unilateral Arytenoid Lateralization on the Rima Glottidis in the Canine Larynx Veterinary Surgery Volume 31, Issue 6, pages 589–595.

Permanent Tracheostomy in Dogs: A life-saving surgical option for severe upper airway obstruction.

Permanent tracheostomy is a well-recognized surgical technique used in animals and humans as a salvage procedure to treat severe upper airway obstruction. Although the technique has been used for many years with success, there are many misconceptions among animal owners and veterinarians about the long-term care and complications. Many feel that dogs cannot have a good quality of life because of the problems associated with tracheostomy. Owners frequently expect that dogs with permanent tracheostomy will have an appliance, i.e. a metal or plastic tube that resides with in the trachea and needs constant care.

Indications for tracheostomy in dogs include: severe laryngeal obstruction due to laryngeal paralysis, collapse, neoplasia, or trauma, pharyngeal neoplasia that obstructs the larynx, and non-resectable proximal tracheal neoplasia.

Although cats may also develop disorders causing severe upper airway obstruction, permanent tracheostomy is associated with frequent, severe complications such as excessive mucous production and stoma stricture.(1) As a result, tracheostomy is rarely recommended in cats.

Preoperative Considerations

Dogs being considered for tracheostomy should be thoroughly evaluated with particular emphasis on the respiratory tract.  A complete history and physical examination followed by appropriate imaging such as thoracic radiographs are important before performing general anesthesia and surgery. Cervical radiographs and even tracheoscopy may be necessary to be certain that the respiratory tract downstream from the larynx is normal. Also, carefully examine the dogs’ ventral cervical area to determine suitability for creating a tracheostomy stoma. Some dogs, such as brachycephalic breeds, have very short necks with excessive skin that can cause problems with skin flaping over the stoma causing obstruction.

Surgical Technique

The dog is placed in ventral recumbency with the neck hyperextended over a soft towel and the front legs extended caudally. The ventral cervical area is clipped and prepared for aseptic surgery. A ventral midline skin incision is made from the larynx to just cranial to the manubrium.  The paired sternohyoideus muscles are divided on their midline using sharp dissection. A large horizontal mattress suture of 2-0 or 3-0 PDS is placed across the sternohyoideus muscles, dorsal to the trachea, to allow retraction of the muscles and cause ventral displacement of the trachea.(Fig. 1) 

Fig. 1: Ventral midline cervical approach for permanent tracheostomy.
The sternohyoideus muscles have been divided and a horizontal mattress suture
is being placed in the muscles to tuck the muscle under the trachea.

Care is taken to avoid trauma to the recurrent laryngeal nerves during passage of the suture. A rectangular window is created in the trachea from the 3^rd to the 7^th ring (4 rings included in the tracheal opening).(Fig. 2) 

Fig. 2: The rectangular window is being created in the tracheal wall.
Note the endotracheal tube present in the tracheal lumen.

The tracheal incisions are begun by incising between rings 3 and 4, then between rings 7 and 8. Be careful not to puncture the cuff of the endotracheal tube when making the initial tracheal incisions. These parallel incisions are then connected using scissors to complete the rectangular shaped defect in the trachea.(Fig. 2)

Close the tracheal wall to the skin in a simple interrupted pattern to create the tracheostomy stoma. Excise a rectangular shaped section of skin on each side of the tracheostomy site to allow the skin incsion to match the rectangular window in the trachea. The suture bites of trachea include the cartilage, and the bites of the skin are placed split thickness, entering the dermal layer and exiting the epidermis.  This allows for accurate apposition of the epidermis to the tracheal mucosa. As in urethrostomy closure, take suture bites from inside out, i.e., start in the tracheal lumen and then take the bite of the skin. The corners of the window are closed first (Fig. 3,4); then the remaining areas are closed in a similar fashion.(Fig. 5) Absorbable suture such as 3-0 or 4-0 PDS is used to avoid having to remove them once the stoma has healed. The skin incisions cranial and caudal to the stoma are then closed routinely.

Fig. 3: The 4 corners of the rectangular tracheal window are closed first.
Note the "inside-out" sequence of suture placement.

Fig. 4: The corner sutures have been placed.

Fig. 6: Completed suture closure of the tracheal stoma. 

Postoperative Care

Alleviation of inspiratory dyspnea is immediate after permanent tracheostomy. See below video of an elderly labrador with laryngeal paralysis before and after permanent tracheostomy. Although laryngeal tie-back is the treatment of choice for most dogs with laryngeal paralysis, permanent tracheostomy was chosen in this dog due to high risk for aspiration pneumonia.

Besides routine postoperative care such as analgesics, cleansing of the stoma is important to prevent build up of discharge and debris. (Fig. 6) Gently wiping the skin around the stoma with moistened gauze sponges is sufficient.

Fig. 6: Typical appearance of a recently preformed permanent tracheostomy
in a Yorkshire Terrier with severe laryngeal collapse.

Owners should be advised to avoid putting anything inside of the trachea and to not use any irritating materials around the stoma such as peroxide or other antiseptics. Small amounts of a petroleum-based ointment (e.g., triple antibiotic ointment) can be placed on the skin around the stoma to prevent discharge from adhering to the skin and make cleaning easier. Discharge from the tracheal stoma tends to gradually decrease over the first few weeks postoperatively. Systemic antibiotics are not routinely prescribed since incisional infections are very rare.

Life Style Limitations

Dogs with a permanent tracheostomy cannot go swimming and should avoid very dusty environments or running in tall grass or weeds. These dogs will also will have difficulty barking or at least have a softer sound than pre-operatively. In rare cases dogs with long hair will need clipping of the hair around the stoma to prevent irritation of the tracheal mucosa and accumulation of debris.

Prognosis

Most dogs with permanent tracheostomy do well and have minimal chronic problems. The most common long-term postoperative problems are pneumonia and stricture of the stoma requiring surgical revision.(2) In a recent study sudden death occurred after tracheostomy in 5 of 19 dogs at variable times after surgery, presumably due to obstruction of the trachea although necropsy was not performed in any of the cases.(2)

Permanent tracheostomy is considered an appropriate surgical option for dogs with severe upper airway obstruction. Complications can occur but some, like stoma stricture and skin fold occlusion, can be treated by revision surgery. Owner education is important to explain potential risks and life style limitations.

References

1. Stepnik MW1, Mehl ML, Hardie EM et. al. Outcome of permanent tracheostomy for treatment of upper airway obstruction in cats: 21 cases (1990-2007). J Am Vet Med Assoc. 2009 Mar 1;234(5):638-43.

2. Lindsay L. Occhipinti and Joe G. Hauptman. Long-term outcome of permanent tracheostomies in dogs: 21 cases (2000–2012) Can Vet J. Apr 2014; 55(4): 357–360.

Surgical Correction of Enlongated Soft Palate in Dogs: Helping brachycephalics breathe.

The soft palate (SP) in the dog forms the partition between the oral and nasopharynx. The cranial border of the SP is attached to the hard palate, and the caudal border extends to the tip of the epiglottis.  Elongated soft palate is one aspect of brachycephalic syndrome and is common in dogs such as English bulldogs, pugs, and Boston terriers. The soft palate is considered elongated if it extends caudally beyond the articulation with the epiglottis. (Fig. 1) 

Fig. 1: Elongated soft palate in a bulldog. (the dog is in ventral recumbency).
Note the tonsils on each side of the palate.

It causes obstruction of the glottis and stertorous breathing which can be a significant respiratory problem in affected dogs. Concomitant stenotic nares worsen the condition by increasing inspiratory effort and causing further extension of the SP into the airway. (see blog on stenotic nares, May 10, 2014)

After obtaining a thorough history and performing a physical examination, take thoracic radiographs to rule out hypoplastic trachea and complications of upper airway obstruction such as pneumonia or pulmonary edema.

Surgical Procedure

A variety of surgical techniques have been described for correction of elongated SP.  The basic objective of surgery is to remove the portion of SP that is causing airway obstruction.  The amount of tissue to be resected is determined by either measuring the portion of SP that extends beyond the tip of the epiglottis, or by removing the portion of SP that extends beyond the caudal pole of the tonsils. (Fig. 2)  

Fig. 2: Incision line for removal of the excess soft palate.
The line connects the caudal pole of the tonsils.

Resection of too much tissue can result in nasal regurgitation of food and water with resultant aspiration pneumonia.

Since hemorrhage is a potential complication of resection, some authors recommend placing a clamp across the area to be removed, removing tissue using electrocautery, or injecting the tissue with epinephrine.  The author does not recommend these techniques since they encourage tissue edema that can be a life-threatening post-operative complication. Surgical laser and the Ligasure device have also been used for soft palate resection.  An atraumatic “cut and sew” technique described many years ago has been very successful in the author's experience and remains my procedure of choice.(1)

Place the animal in ventral recumbency with the head at the end of the table and the mouth held open with an oral speculum. (Fig. 3)  

Fig. 3: Patient positioning for soft palate surgery

Be sure that the endotracheal tube has a competent cuff that is appropriately inflated to prevent aspiration of blood during the procedure. Administer intravenous dexamethasone (0.1 mg/kg) to help control tissue edema secondary to surgical manipulation. Briefly remove the endotracheal tube to examine the soft palate and compare its length to the epiglottis. Replace the tube and secure it in place. Grasp the middle of the SP with an Allis tissue forceps and place stay sutures (4-0 PDS or Monocryl, taper needle) at the lateral aspects of the SP where the incision will be made. (Fig. 4)  

Fig. 4: Stay sutures have been place at the proposed site of incision (dotted line)
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
J Am An Hosp Assoc 19: 288-92

Sharply incise the soft palate with long-handled curved Metzenbaum scissors. (Fig. 5)  

Fig. 5: Angled Metzenbaum scissors (above) are useful for incision of the soft palate.
Conventional scissors are shown below.

Incise half way across the palate; the mucosa of this cut portion is then sutured with the long end of the stay suture in a simple continuous pattern. (Fig. 6) 

Fig. 6: The soft palate has been partially incised and suture closure begun.
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
 J Am An Hosp Assoc 19: 288-92

Then incise across the remaining palate and suture the mucosa in a similar fashion. (Fig. 7)

Fig.7: Completed excision and closure of the soft palate.
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
J Am An Hosp Assoc 19: 288-92

Hemorrhage is usually not a significant problem once the incisions are closed.  The trachea is gently suctioned if hemorrhage was excessive. To check the soft palate for adequate resection of tissue, briefly remove the endotracheal tube to allow comparing the soft palate length to the epiglottis, then replace the tube for the remainder of the dog's recovery from anesthesia.

Postoperative Care

Post-operatively, leave the endotracheal tube in place as long as possible until the animal is fully awake.  The animal should recover in a cool environment and be observed closely for evidence of airway obstruction due to tissue edema.  Keeping the chin elevated seems to help brachycephalic dogs move air during anesthesia recovery. The intravenous steroids can be repeated if edema is suspected. Tramadol is administered for 5 days for analgesia.

Although most dogs recover without incident after soft palate resection, if complications occur they can be life threatening. Therefore recovery from surgery should be in a hospital that has 24 hour care at least for the first night after the procedure. Results of surgery are usually very good; some inspiratory noise may remain but respiratory function should be improved. One study found a good to excellent outcome in 34 dogs with long-term follow up after surgery for brachycephalic syndrome.(2)

References

1. Bright RM, Wheaton LG. A modified surgical technique for elongated soft palate. J Am An Hosp Assoc. 1983; (19): 288-92.

2. Surgical correction of brachycephalic syndrome in dogs: 62 cases (1991-2004).

Riecks TW, Birchard SJ, Stephens JA. J Am Vet Med Assoc. 2007;230(9):1324-8.