This series on oral care and dental disease is provided by Eric M. Davis, DVM, a Diplomate of the American Veterinary Dental College.  Dr. Davis is the former Director of the Dental Referral Service at the Cornell University Hospital for Animals, and is currently the Director of Animal Dental Specialists of Upstate New York, a referral clinic for veterinary dentistry and oral surgery located in Fayetteville, New York. Dr. Davis can be contacted at emdavisdvm@gmail.com or at 315-445-5640.

THUFFERIN THUCCOTASH: THE TRUE THTORY OF THYLVETHTER THE CAT

Once upon a time, a kindly, middle-aged lady was walking along a road in central New York when suddenly, she noticed a little black shape rustling under some leaves.  "I thought I saw a pussy cat" she said to herself (she did not have a speech impediment like Tweety Pie).  The lady stopped and looked closer. "I did!" she exclaimed aloud. "I did see a pussy cat!"  And so the lady picked up the little creature and she said, "I will call you Sylvester," and she brought the kitten home.  It soon became apparent that the frail kitten had a medical problem, in that it could barely open its mouth. Sylvester could manage to lick up milk replacer from a dish, but when canned or ground-up dry kitten food was added to the milk replacer, only the liquid could be consumed because Sylvester's mouth was frozen shut. Not only was the kitten's growth stunted because he could not eat solid food, but he was also sneezing a lot, and green-yellow discharge was coming out of Sylvester's nose, making it hard for the little kitten to breathe. Fortunately, the kindly, middle-aged lady actually worked at a local animal hospital, and the veterinarian examined Sylvester and took X-rays. In addition to the kitten's jaws being frozen shut, there appeared to be a cleft palate as well, which explained why Sylvester was sneezing…milk replacer was entering his nasal passages. That ominous finding meant that although chronic rhinitis was occurring, the oro-nasal communication could also eventually lead to fatal, inhalation pneumonia. No one expected Sylvester to live; no one, except the kindly, middle-aged lady.

Antibiotic prescription after antibiotic prescription was used to treat Sylvester's respiratory disease and prevent inhalation pneumonia, and the kindly, middle-aged lady used a syringe, several times each day, to slowly administer liquefied, watered-down cat food into Sylvester's mouth to keep him alive. The lady worked and worked, and she saved her money so that one day, she might be able to have Sylvester's mouth and nose problem fixed.  Four long years went by, and because of the dedicated efforts of the kindly, middle-aged lady, Sylvester miraculously remained alive.  Then, in September of 2011, the lady brought Sylvester to my office for an evaluation to see what could be done.

Physical examination revealed a thin adult feline patient (Body Condition Score 3/9) with copious, bilateral nasal discharge. Oral examination of the conscious patient was limited, as the mouth could not be opened. The maxillary dental arch overlapped the mandibles by nearly a centimeter, and the fur of the chin and neck was stained with saliva (Figure 1.). The mandibular canine teeth appeared to be penetrating the palate, and two, large oronasal fistulas were visible. Gentle retraction of the lips revealed severe gingival inflammation associated with heavy deposition of dental calculus. Tooth resorption was identified affecting several premolar teeth. My treatment plan called for the patient to be placed under general anesthesia using injectable agents until a tracheostomy could be performed. If extensive fibrosis prevented the mouth from opening, bilateral temporomandibular joint arthroplasty, bilateral condylectomy, or caudal segmental mandibulectomies might benecessary to enable the mouth to be opened. After getting the mouth open, a two-staged procedure for closing the palatal defects was proposed, in which all of the cheek teeth would be removed during the first procedure. A large diameter gastrostomy tube would also be placed during the first procedure to provide nourishment and medication until the palatal defects could be closed.  During a second surgery, planned six to eight weeks after the first procedure, an xenograft of cadaveric, freeze-dried canine bone would be secured to the palatal shelves of the right and left maxillary bones, and with the teeth no longer present, large, buccal mucosa advancement flaps from both sides would be developed which would then be apposed at the palatal midline to cover the xenograft and thereby create a permanent, two-layer barrierto separate the oral cavity from the nasal cavity. The kindly middle-aged lady agreed to the proposed plan and an appointment for the first surgery was scheduled.

Following induction of general anesthesia, a tracheostomy tube was placed to enable administration of inhalant anesthetic gas and oxygen. Radiography of the temporomandibular joints revealed that Sylvester apparently sustained maxillofacial trauma early in life which resulted in bilateral temporomandibular luxation.  Subsequent muscle contraction and ossification of the joints essentially fused the cat's mandibles so that his mouth was permanently closed. Unilateral arthroplasty of the left temporomandibular joint was inadequate to permit the mouth to be opened. Even with arthroplasty of the contralateral right TMJ, the lower jaw remained immobile. The skin incision to expose the right TMJ was then extended rostrally to provide surgical access to the caudal aspect of the right mandibular body. An osteotome was used to perform a caudal segmental mandibulectomy of the right mandible, and that maneuver permitted the mouth to be opened and inspected (Figure 2.). Two large oronasal defects were located in the palate over the greater palatine fissures (Figure 3.). A full-mouth, intraoral radiographic survey of the teeth and associated osseous structures was then obtained.  Both advanced periodontitis and tooth resorption lesions were identified affecting nearly all of the remaining teeth including the canine teeth. Following placement of regional nerve blocks, all of the patient's teeth were serially extracted by quadrant, and when post-extraction radiographs confirmed removal of all dental elements, the remaining alveolar bone was reduced in height, and the gingival tissue was mobilized and sutured over the extraction sites with 5-0 Monocryl®.  A 24 French gastrostomy tube was placed using an ELD applicator device, the wound over the left temporomandibular joint was closed, a transdermal fentanyl patch was applied, and the patient was allowed to recover from general anesthesia.

Sylvester recovered uneventfully and the owner reported that her little kitty, which had never been able to groom himself, now was able to lick and clean his fur regularly. By feeding Sylvester through the gastrostomy tube rather than syringe-feeding him by mouth, the nasal discharge and sneezing dissipated, and Sylvester began to gain weight. Sylvester was anesthetized for the second procedure six weeks after the first surgery.  Following induction of general anesthesia and placement of regional nerve blocks, full-thickness mucoperiosteal tissue flaps were created and reflected from the maxillary alveolar ridges that previously supported the teeth. The flaps were mobilized all the way to the edges of the lips so that the buccal mucosa that lined the vestibule on either side of the oral cavity was included. The alveolar bone bordering the palatal defects was reduced in height and contoured so that the flaps would be able to be apposed without undue tension. A 40mm X 60mm freeze-dried canine cadaveric tissue graft was then re-hydrated in sterile saline. Small holes were drilled through the maxillary and incisive bones, and 4-0 Monocryl® suture was threaded through the holes and through the graft, thereby securely attaching the xenograft to the patient's palatal bones. The soft tissue flaps were then apposed and sutured at the palatal midline over the xenograft to result in a permanent separation between the nasal cavity and the oral cavity (Figure 4.).

Although 90% of the oronasal communication had been permanently closed, a small, 3 x 4 mm defect remained open near the rostral edge of the original defect.  Revision surgery was performed eight weeks after the second procedure to close the last remaining opening in Sylvester's palate (Figure 5.).  Sylvester began to eat voluntarily soon thereafter to the extent that his weight increased by 20% compared to his pre-treatment weight.  The moral of the story is that, like the kindly, middle-aged lady, one should never give up hope. With courage, persistence, and inner strength, even the greatest challenge can successfully be overcome (Figure 6.).