Mark M. Smith

Lymph Node Staging of Oral and Maxillofacial Neoplasms in 31 Dogs and Cats

A retrospective study was performed to report the histologic examination results of regional lymph nodes of dogs and cats with oral or maxillofacial neoplasms. Twenty-eight dogs and 3 cats were evaluated. Histologic examination results of standard and serial tissue sectioning of regional lymph nodes were recorded. When available, other clinical parameters including mandibular lymph node palpation, thoracic radiographs, and pre- and postoperative fine needle aspiration of lymph nodes were compared with the histologic results. Squamous cell carcinoma, fibrosarcoma, and melanoma were the most common neoplasms diagnosed in dogs. Squamous cell carcinoma and fibrosarcoma were diagnosed in cats. Of the palpably enlarged mandibular lymph nodes, 17.0 % had metastatic disease histologically. Radiographically evident thoracic metastatic disease was present in 7.4 % of cases. Preoperative cytologic evaluation of the mandibular lymph node based on fine needle aspiration concurred with the histologic results in 90.5 % of lymph nodes examined. Postoperative cytologic evaluation of fine needle aspirates of regional lymph nodes concurred with the histologic results in 80.6 % of lymph nodes examined. Only 54.5 % of cases with metastatic disease to regional lymph nodes had metastasis that included the mandibular lymph node. Serial lymph node sectioning provided additional information or metastasis detection. Cytologic evaluation of the mandibular lymph node correlates positively with histology, however results may fail to indicate the presence of regional metastasis. Assessment of all regional lymph nodes in dogs and cats with oral or maxillofacial neoplasms will detect more metastatic disease than assessing the mandibular lymph node only.

Orbital Penetration Associated with Tooth Extraction

Three cats and 2 dogs were evaluated for ophthalmologic complications associated with teeth extraction procedures. Orbital penetration leading to ocular and. in one case, brain trauma was secondary to iatrogenic injury from a dental elevator. Outcomes included enucleation of the affected eye in 3 cases, and death from brain abscessation in 1 case. Early treatment or, preferably, referral to a veterinary ophthalmology specialist may prevent such outcomes. Awareness of the anatomical proximity of caudal maxillary tooth roof, and the orbit, appropriate interpretation of diagnostic intraoral dental radiographs, and technical proficiency in tooth extraction techniques will minimize these complications in veterinary dental practice.

Skull Trauma and Mandibular Fractures

This article discusses the treatment of skull and mandibular fractures in small animals as well as fixation techniques, including interdental fixation, external skeletal fixation, intraoral splints, wiring, and pinning. Information is provided on the treatment of loose and damaged teeth in the fractured area. Management of temporomandibular joint luxation also is addressed.

Regional Peripheral Vascular Supply Based on the Superficial Temporal Artery in Dogs and Cats

Cutaneous arterial blood supply to the temporal region was evaluated in 8 dogs and 8 cats. Subtraction radiography and angiography of the carotid and superficial temporal arteries were used in 4 dogs and 4 cats to determine arterial blood supply to the temporal region and frontalis muscle. A myocutaneous axial pattern flap based on the superficial temporal artery and frontalis muscle may be indicated for cosmetic reconstruction in dogs and cats following surgical resection of neo‐plastic lesions or traumatic wounds in the maxillofacial region. The frontalis muscle was identified as the thin subcutaneous continuation of the platysma muscle extending cranially and rostrally. Dissection of the temporal region in 4 dogs and 4 cats revealed the subcutaneous location of the superficial temporal artery as it continues rostrally from the caudal aspect of the zygomatic arch.

Surgical Extraction of Impacted Teeth in a Dog

J.VET.DENT. Vol. 23 No. 3 September 2006 A 2-year-old, 28.2 kg, male/neutered retriever mixed-breed dog from a non-profit organization was presented for missing permanent teeth and an abnormally positioned mandibular canine tooth. Examination performed by the referring veterinarian when the dog was 14-months-old indicated that the left maxillary (204) and mandibular (304) canine teeth and three mandibular incisor teeth were missing. Examination 6-months later by the same veterinarian confirmed that the teeth were still missing and that the right mandibular canine tooth (404) was abnormally positioned and causing trauma to the hard palate. The dog was subsequently referred for possible tooth impaction and correction of the clinical malocclusion. Laboratory tests including a serum chemistry panel and complete blood count were within normal limits. The interdigitating premolar occlusion was considered normal. Initial oral examination demonstrated that 404 was interfering with the hard palate. The trauma from the abnormal occlusion had caused a defect in the palatal mucosa (Fig. 1). The 404 and right mandibular second (402) and third (403) incisor teeth had enamel defects affecting the majority of the visible crown. The 204, 304, all left mandibular incisor teeth (301, 302, 303) and the right mandibular first incisor tooth (401) were absent. Based on the initial oral examination, a differential diagnosis of tooth absence or impaired tooth eruption was considered. Other parameters of the physical examination were normal. The dog was premedicated with buprenorphine (0.01 mg/kg) and glycopyrrolate (0.015 mg/kg) intramuscularly 35-minutes before induction. The dog was induced with intravenous propofol (8 mg/kg) and maintained on oxygen (1.5 l/minute) and isoflourane ranging from 0.5-2.5 %. Carprofen (4.4 mg/kg SQ) and ampicillin (22 mg/kg IV) were administered after induction. Electrocardiogram, temperature, pulse oximetry, heart rate, respiration rate, and indirect blood pressure were monitored and recorded every 10-minutes throughout the procedure. A balanced electrolyte solution was administered during the procedure (10.0 ml/kg/hr). Temperature regulation was achieved by use of a covered circulating water heating pad below the dog and an electric heating pad placed over a blanket on top of the dog and set at the lowest temperature. The eyes were lubricated at the beginning of the procedure and periodically throughout with artificial tears ointment. Intraoral dental radiographs showed impaction of 204, 303, and 304. The 401, 301, and 302 appeared to be absent. There were no radiographic signs of periapical infection or other abnormalities associated with 404 (Figs. 2 and 3). Treatment options for these abnormalities included surgical extraction of impacted dentition or observation for clinical problems. Impacted teeth that are not surgically extracted can develop into dentigerous cysts, therefore surgical extraction of all impacted teeth was performed in this case. Orthodontic Figure 1

Resection of mast cell tumor of the lip in a dog.

A 10-year-old Boston terrier dog was presented for treatment of a 2-cm mast cell tumor of the left upper lip and nasal planum immediately adjacent to the philtrum and ventral to the nares. CO2 laser was used for resection of the lesion. Wound reconstruction was performed using bilateral labial advancement flaps.

Bilateral maxillary periodontal ligament hamartoma in a dog.

A 12.5-year-old dog was presented for severe periodontal disease and bilateral maxillary enlargement. Radiographs of the maxilla showed generalized root resorption, ankylosis, and rarefaction of bone with focal radiodense areas. Surgical tooth extraction of multiple maxillary teeth and bilateral incisional biopsies of the periodontal tissue and maxilla in the legion of the maxillary fourth premolars were performed. Histopathologic examination showed features typical of fully differentiated periodontal ligament with abundant cementum/alveolar lining bone and sparce odontogenic epithelial cell rests. Histopathology in conjunction with radiographic and clinical signs suggested a diagnosis of bilateral periodontal ligament hamartoma. Examination 3-months postoperatively indicated uncomplicated healing of the extraction and biopsy sites with no resolution of the maxillary enlargement.

Evaluation of horizontal and vertical tracheotomy healing after short-duration tracheostomy in dogs

PURPOSE The purpose of the study was to assess healing of horizontal and vertical tracheotomy after short-duration tracheostomy in dogs using clinical, radiographic, endoscopic, and histologic methods. MATERIALS AND METHODS Horizontal tracheotomy (n = 6) between the third and fourth tracheal rings or vertical tracheotomy (n = 6) across tracheal rings three through five was performed for airway management during laryngoplasty. Tracheostomy tubes were maintained for 6 hours with low-pressure cuff inflation time limited to the first 1.5 hours. Cervical radiographs and tracheoscopy were performed preoperatively and at postoperative weeks 2, 4, 8, and 12. Ten of the 12 dogs were killed 12 weeks after tracheostomy. RESULTS There was no significant difference in preoperative and postoperative tracheal diameter or change in endoscopic tracheal circumference at the tracheostomy site when dogs were compared based on type of tracheotomy. Three dogs with horizontal tracheotomies had evidence of scar (web) within the tracheal lumen 12 weeks after surgery. All vertical tracheotomies had a mild, ventral, triangular deformity. Histologic examination of vertical tracheotomy sites showed complete restoration of the pseudostratified columnar epithelium. Horizontal tracheotomies healed with a single layer of columnar epithelium. Intraluminal scar was composed primarily of loose connective tissue. CONCLUSION Based on the results of this study, vertical tracheotomy shows more consistent healing compared with horizontal tracheotomy after short-duration tracheostomy. No evidence was found to support the preferential recommendation of horizontal tracheotomy for short-duration tracheostomy airway management.

Surgery for cervical, sublingual, and pharyngeal mucocele.

Mucocele is the most common clinically recognized disease of the salivary glands in dogs. A mucocele is an accumulation of saliva in the subcutaneous tissue and the consequent tissue reaction to saliva. The mucocele has a nonepithelial, nonsecretory lining consisting primarily of fibroblasts and capillaries. The incidence of salivary mucocele reportedly is fewer than twenty in 4,000 dogs. Although the condition has been reported in dogs as young as 6-months of age, salivary mucocele occurs most often in dogs between 2 and 4-years of age. Salivary mucocele occurs more frequently in German shepherds and miniature poodles. Trauma has been proposed as the cause of salivary mucocele because of the activity of young dogs and the documented damage to the salivary gland/duct complex and the formation of mucocele. The inability to induce salivary mucocele traumatically in healthy dogs suggests the possibility of a developmental predisposition in affected dogs. The sublingual gland is the most common salivary gland associated with salivary mucocele. Sialography has shown that the origin of the mucocele most often occurs in the rostral portion (that portion of the sublingual gland superimposed on the mandible) of the sublingual gland/duct complex. Regardless of the location of origin, mucocele usually forms near the intermandibular area (cervical mucocele). Other locations associated with the formation of mucocele because of a sublingual gland/duct defect include under the tongue, which involves the floor of the mouth (sublingual mucocele), and the pharynx (pharyngeal mucocele). The clinical signs associated with salivary mucocele depend on the location of the mucocele. A cervical mucocele is initially an acute, painful swelling resulting from an inflammatory response. Cessation of the inflammatory response results in a marked decrease in swelling. A decreased inflammatory response allows for the more common presenting history of a slowly enlarging or intermittently large, fluid-filled, nonpainful swelling. Blood-tinged saliva secondary to trauma caused by eating, poor prehension of food, or reluctance to eat are clinical signs that can be associated with sublingual mucocele. The most common clinical signs associated with mucocele of the pharyngeal wall are respiratory distress and difficulty in swallowing secondary to partial obstruction of the pharynx. Diagnosis of salivary mucocele is based on clinical signs, history, and results of paracentesis. Mucocele paracentesis reveals a stringy, sometimes blood-tinged fluid with low cell numbers. Mucin and amylase analyses of the fluid are not reliable diagnostic procedures. A chronic cervical mucocele may contain palpable firm nodules that are remnants of sloughed inflammatory tissue previously lining the mucocele. Sialoliths are concretions of calcium phosphate or calcium carbonate and may occur with chronic mucocele. Physical examination and history usually denote the origin of the mucocele. Cervical mucoceles that appear on the midline usually shift to the originating side when the patient is placed in exact dorsal recumbency. Sialography can be used to determine the affected side if careful observation and palpation are unsuccessful. The most common indication for sialography is to determine the location of a salivary gland/duct defect in patients with salivary mucocele. Sialography is also a diagnostic aid when considering traumatic injury to one of the salivary glands, salivary neoplasia, a mass or fistulous tract of unknown origin in the head and neck region, or a foreign body in the head or neck. The disadvantages of sialography include the need for general anesthesia and the difficulty associated with locating the duct opening(s). Various methods have been used to treat cervical mucoceles. Mucocele drainage, removal of the mucocele only, and chemical cauterization of the mucocele have been reported. The basis for these therapies was the belief that a mucocele was a true cyst with a secretory lining. The fact that a mucocele is not a cyst but is a reactive encapsulating structure has prompted surgical removal of the affected gland/duct complex. The intimate anatomic association of the sublingual and mandibular glands and their ducts requires resection of both structures. Another technique for treating pharyngeal and sublingual mucoceles involves marsupialization. However, resective surgery is preferred for pharyngeal mucocele since life-threatening upper airway compromise and morbidity from swallowing dysfunction (e.g. aspiration pneumonia) are potential complications of conservative management or recurrence. Surgical removal of both the sublingual and mandibular salivary glands, combined with drainage of the mucocele, has been advocated for treating cervical, sublingual, and pharyngeal mucocele and is described step-by-step.

Composite restoration of enamel defects.

Enamel defects in the crowns of teeth can be acquired or congenital. These defects affect cosmesis and may result in complications such as endodontic pathology. Proper treatment of these defects requires understanding of the basic principles of restoration. The goal of restorative dentistry should be to achieve a functional tooth that closely matches the normal dental anatomy while being able to withstand occlusal forces and contacts. The underlying cause of these defects must also be identified in order to determine the optimal treatment plan and to prevent potential recurrence of the lesion. Restoration of an enamel defect using a flowable composite material is described step-by-step.