Mandibulectomy and maxillectomy as a treatment for bone invasive oral neoplasia in the dog

From 1999 to 2001, 31 dogs with bone invasive tumours of the jaws were treated by maxillectomy or mandibulectomy at the Hofheim Small Animal Clinic (Germany). In addition to surgery, 3 dogs received chemotherapy, two due to metastatic spread and one after marginal resection of an extensive tumour. The goal of this study was to describe epidemiology and pathology of the various tumours, review the rate of postoperative complications and determine postoperative jaw function with regard to food and water uptake and grasping of sticks or balls. Patient survival times were evaluated and compared to published data. Medium and large sized dogs were overrepresented in this study; the average age was 9.9 years, 20 (65%) of the animals were male and 11 (35%) were female. Of the 31 tumours, 23 (74%) were malignant, 8 (26%) were benign; 21 (68%) were located in the mandible, 10 (32%) in the maxilla. The histologic diagnoses were as follows: squamous cell carcinoma (n = 10, 32%), malignant melanoma (n = 8, 26%), acanthomatous epulides (n = 7; 23%), fibrosarcoma (n = 3; 10%) and one each of osteosarcoma, atypical histiocytoma and central ameloblastoma. Only one dog suffered major postoperative complications resulting in euthanasia. Follow up was available for 23 patients using an owner questionnaire to evaluate function of the jaws after resection. One dog experienced problems that were felt to result in a significant reduction in quality of life. Three other patients had difficulties grasping hard objects but had no problems with food or water uptake. In the remaining dogs no significant functional deficits were reported by the owners. Functional deficits were not associated with the extent or location of jaw resection. Survival times were available from 26 patients, of these 18 were still alive with an average survival time of 14 months. Maxillectomy or mandibulectomy is an appropriate method for treatment of bone invasive tumours of the jaws and has a low complication rate. In most cases postoperative function of the jaws is undisturbed.