Temporomandibular Joint Gape Angles in Normal and Painful Domestic Felines.

The purpose of this study was to determine and compare the gape angles (temporomandibular joint range of motion with mouth opening) of conscious and anesthetized domestic felines and to compare gape angles with and without evidence of oral pain. This prospective study evaluated the gape angle of 58 domestic felines. The cats were grouped into painful (n = 33) and nonpainful cohorts (n = 25) and gape angles were compared during conscious and anesthetized conditions. Gape angles were determined based on measurements of the maximal interincisal distance and lengths of the mandible and maxilla followed by calculation of the law of cosines. The mean feline gape angle (standard deviation) was determined to be 45.3° (8.6°) and 50.8° (6.2°) for conscious and anesthetized felines respectively. There was no significant difference between painful and non-painful feline gape angles during conscious (P = .613) or anesthetized (P = .605) evaluations. There was a significant difference between anesthetized and conscious gape angles (P < .001) for both painful and non-painful cohorts. This study determined the standardized, normal feline temporomandibular joint (TMJ) gape angle in both conscious and anesthetized states. This study suggests that the feline gape angle is not a useful indicator of oral pain. By determining the feline gape angle, which was previously unknown, further evaluation of its utility as a non-invasive clinical parameter for evaluation of restrictive TMJ motions as well as its use for serial evaluations may be pursued.

Application of a maxillary transfacial approach to the caudal oral cavity and orbitozygomaticomaxillary complex in dogs.

Surgical access and visualization for excision of large pathologic lesions of the orbitozygomaticomaxillary complex (OZMC) and caudal oral cavity can be a challenge in veterinary oromaxillofacial surgery and may limit one's ability to perform such procedures. Combined intra- and extra-oral approaches as well as commissurotomy have been advocated in the past. However, each of these approaches present unique limitations specific to each approach. A transfacial approach that ameliorated these limitations could be advantageous. In this descriptive cohort study, we investigate the application and outcomes of a maxillary transfacial approach to the OZMC and caudal oral cavity in six client-owned dogs. The approach is based on the Weber-Ferguson approach for human applications and provided excellent exposure of the intended region in all six patients. We contend the maxillary transfacial approach provides some advantages to the more conventional combined intra-oral/extra-oral approach or commissurotomy for excision of large pathologic lesions of the OZMC and caudal oral cavity.

Virtual surgical planning and 3D printing: Methodology and applications in veterinary oromaxillofacial surgery.

Virtual surgical planning is the process of planning and rehearsing a surgical procedure completely within the virtual environment on computer models. Virtual surgical planning and 3D printing is gaining popularity in veterinary oromaxillofacial surgery and are viable tools for the most basic to the most complex cases. These techniques can provide the surgeon with improved visualization and, thus, understanding of the patients' 3D anatomy. Virtual surgical planning is feasible in a clinical setting and may decrease surgical time and increase surgical accuracy. For example, pre-operative implant contouring on a 3D-printed model can save time during surgery; 3D-printed patient-specific implants and surgical guides help maintain normocclusion after mandibular reconstruction; and the presence of a haptic model in the operating room can improve surgical precision and safety. However, significant time and financial resources may need to be allocated for planning and production of surgical guides and implants. The objectives of this manuscript are to provide a description of the methods involved in virtual surgical planning and 3D printing as they apply to veterinary oromaxillofacial surgery and to highlight these concepts with the strategic use of examples. In addition, the advantages and disadvantages of the methods as well as the required software and equipment will be discussed.

Combined Gap and Interpositional Arthroplasty Utilizing Three-Dimensional Printed Model in a Dog with Temporomandibular Joint Ankylosis and Pseudoankylosis.

Objective: To report the surgical treatment of a canine with both ankylosis and pseudoankylosis of temporomandibular joint (TMJ). Methods: The patient presented for inability to open his mouth. Facial asymmetry with normal dental occlusion was appreciated and computed tomography (CT) was performed. CT was used to diagnose ankylsosis and pseudoankylosis of left TMJ secondary to chronic maxillofacial trauma. A gap arthroplasty followed by interpositional arthroplasty using temporalis muscle fascia was performed to remove the site of fusion and prevent re-ankylosis between remaining cut boney surfaces. A three-dimensional (3D) printed skull for surgical planning and intraoperative spatial localization was employed. Results: Following preoperative and intraoperative evaluation of the 3D printed skull, the surgery was performed successfully without major complications. The patient's TMJ range of motion was markedly improved and remains improved as noted by inter-incisal distance measurements, ability to pant, and ease of chewing. Conclusion: A combined Gap and interpositional arthroplasty was assisted with the use of a 3D printed skull and immediately resulted in improved TMJ range of motion and patient quality of life. Three-month postoperative CT revealed stable ostectomies with no complications, with the exception of left-sided disuse masticatory muscle atrophy. Long-term follow-up is warranted. Clinical Significance: Three-dimensional printed skull models may be utilized preoperatively and intraoperatively to determine individual variants and landmarks, especially in cases where anatomical structures are difficult to recognize. Gap arthroplasty with interpositional myofascial transposition is an option for a patient with both anklyosis and pseudoankylosis of the TMJ.

CT characterisation and classification of feline temporomandibular joint trauma: a case series of 79 cats.

OBJECTIVES: The aim of this study was to characterise and describe patterns of temporomandibular joint (TMJ) injuries occurring in cats using CT. METHODS: A cross-sectional study was carried out in adherence with the STROBE guidelines. Among the medical and CT records of 79 cats, 158 TMJs were reviewed in a collaborative study between six institutions. RESULTS: TMJ injuries were most commonly unilateral, representing 70.9% of cases. The mandibular condyle was fractured in 88 cases (55.7%) of the 158 TMJs observed. Of those, 84.0% were intra-articular condyle fractures, with the medial half of the mandibular condyle over-represented. Luxations occurred in 32.9% of cases, which was 19.0% of all evaluated TMJs. Rostrodorsal luxations were most common representing 87.0% of all luxations. Temporal bone fractures were observed in 30.4% of all cases, which was 18.4% of TMJs. The majority of fractures were of an unknown cause. When the cause was determined, road traffic accident (RTA) was the most frequent, followed by animal interaction, other external forces (sharp or blunt force) and high-rise trauma. Bilateral injuries were 13.1 times more likely to occur in high-rise trauma (P = 0.01) and temporal bone fracture was significantly associated with RTAs (P = 0.016). No other significant associations were observed between cause of injury and the resulting TMJ injury pattern. CONCLUSIONS AND RELEVANCE: Various TMJ injury patterns can occur in cats as a result of trauma. Intra-articular fractures of the medial half of the mandibular condyle occur most commonly. Although unilateral injuries are more frequent, high-rise trauma tends to present with bilateral lesions. Further studies with a larger sample size should be performed to better understand TMJ patterns of injury and how they relate to possible causes.

Virtual Surgical Planning and 3D Printing in Veterinary Dentistry and Oromaxillofacial Surgery.

Virtual surgical planning and three-dimensional (3D) printing are preoperative processes requiring the acquisition of high-quality imaging data. A surgical treatment plan is created and rehearsed virtually as the operator manipulates the 3D images of the patient within the software. When the operator is satisfied with the plan, including anticipated osteotomies, tumor excision margins, and reconstruction options, physical 3D prints can be produced. This article introduces the reader to the basic concepts involved in virtual surgical planning and 3D printing as well as their implementation in veterinary oromaxillofacial surgery.

Outcomes of cats treated with maxillectomy: 60 cases. A Veterinary Society of Surgical Oncology retrospective study.

Maxillectomy is poorly described for the management of oral tumours in cats and is occasionally not recommended because of the high complication rate and sub-optimal outcome reported in cats treated with mandibulectomy. The purpose of this study was to retrospectively evaluate the complications and oncologic outcome in cats treated with maxillectomy. Sixty cats were included in the study. Maxillectomy procedures included unilateral rostral (20.0%), bilateral rostral (23.3%), segmental (10.0%), caudal (20.0%) and total unilateral maxillectomy (26.7%). Intra-operative and post-operative complications were reported in 10 (16.7%) and 34 (56.7%) cats, respectively. The most common post-operative complications were hyporexia (20.0%) and incisional dehiscence (20.0%). The median duration of hyporexia was 7 days. Benign tumours were diagnosed in 19 cats (31.7%) and malignant tumours in 41 cats (68.3%). Local recurrence and metastatic rates were 18.3% and 4.9%, respectively; the median progression-free interval (PFI) was not reached. The disease-related median survival time was not reached overall or for either benign or malignant tumours. The 1- and 2-year survival rates were, respectively, 100% and 79% for cats with benign tumours, 89% and 89% for cats with malignant tumours, 94% and 94% for cats with fibrosarcomas, 83% and 83% for cats with squamous cell carcinomas, and 80% and 80% for cats with osteosarcomas. Poor prognostic factors included mitotic index for PFI, adjuvant chemotherapy for both PFI and survival time, and local recurrence for survival time. Maxillectomy is a viable treatment option for cats resulting in good local tumour control and long survival times.

Biomechanical Testing of a Calcium Phosphate-Phosphoserine-Based Mineral-Organic Adhesive for Non-invasive Fracture Repair of Mandibular Fractures in Dogs.

Mandibular fracture repair is complicated by limited availability of bone as well as the presence of the neurovascular bundle and an abundance of tooth roots. Fractures at the location of the mandibular first molar teeth are common and it can be particularly challenging to apply stable fixation. Non-invasive fracture repair techniques utilize intraoral placement of fixation devices typically involving polymerized composites and/or interdental wiring. A novel calcium phosphate-phosphoserine-based mineral-organic adhesive was tested ex vivo to determine its effects on augmenting strength of different non-invasive fracture fixation techniques. This study both tested the use of mineral-organic adhesive for the purpose of stabilizing currently used non-invasive fracture repair constructs (intraoral composite splinting ± interdental wiring) and evaluated adhesive alone or with subperiosteally placed plates on buccal cortical bone surface. Aside from controls, not receiving an osteotomy along the mesial root of the mandibular first molar tooth, six treatment groups were tested to evaluate ultimate strength, stiffness, angular displacement, bending moment, and application time. All forms of fixation were found to be significantly weaker than control (p < 0.001). Only the control (p < 0.001) and mineral-organic adhesive and composite (P = 0.002) groups were found to be significantly stronger than wire and composite. No difference was noted in stiffness between any groups with control or wire and composite. Application times varied from the mineral-organic adhesive group (mean = 206 s) to mineral-organic adhesive and composite (mean = 1,281 s). Twenty-three fixation devices exhibited adhesive failure, 20 demonstrated cohesive failure, and 5 failed by cohesive and adhesive failure. When evaluating the ultimate strength of the fixation device groups, mineral-organic adhesive, and composite was shown to be the strongest construct. The use of resorbable bone adhesive and composite may provide a stronger fixation construct over interdental wire and composite for mandibular fracture repair in dogs.

Diagnosis and Management of an Oronasal Fistula Secondary to Nasal Transmissible Venereal Tumor in a Dog.

Canine transmissible venereal tumor (CTVT) is a contagious tumor commonly seen in populations of sexually intact dogs that have close contact with each other. CTVT is one of only 3 known naturally transmissible, contagious tumors in which the mutated tumor cell is thought to have originated in an individual canid about 11000 years ago. Clinical history, signalment, cytological and histologic evaluation are typically sufficient for reaching a diagnosis, although immunohistochemistry(IHC) may be necessary for unique presentations of this neoplasm. This case report describes the diagnosis of an oronasal CTVT using histopathology and IHC, followed by treatment of the tumor with chemotherapy and surgical correction of a defect caused by the tumor.

Reconstruction of a mandibular segmental defect with a customized 3-dimensional-printed titanium prosthesis in a cat with a mandibular osteosarcoma.

CASE DESCRIPTION A 12-year-old neutered male domestic shorthair cat had been treated for a mass arising from the lingual aspect of the caudal right mandibular body. Cytoreductive surgery of the mass had been performed twice over a 2-year period, but the mass recurred following both surgeries. The mass was diagnosed as an osteosarcoma, and the cat was referred for further evaluation and treatment. CLINICAL FINDINGS Clinical findings were unremarkable, except for a 2-cm-diameter mass arising from the lingual aspect of the right mandible and mild anemia and lymphopenia. Pre- and postcontrast CT scans of the head, neck, and thorax were performed, revealing that the osteosarcoma was confined to the caudal right mandibular body, with no evidence of lymph node or pulmonary metastasis. TREATMENT AND OUTCOME The stereolithographic files of the CT scan of the head were sent for computer-aided design and manufacture of a customized 3-D-printed titanium prosthesis. Segmental mandibulectomy was performed, and the mandibular defect was reconstructed in a single stage with the 3-D-printed titanium prosthesis. The cat had 1 minor postoperative complication but had no signs of eating difficulties at any point after surgery. The cat was alive and disease free 14 months postoperatively. CLINICAL RELEVANCE Reconstruction of the mandible of a cat following mandibulectomy was possible with computer-aided design and manufacture of a customized 3-D-printed titanium prosthesis. Cats have a high rate of complications following mandibulectomy, and these initial findings suggested that mandibular reconstruction may reduce the risk of these complications and result in a better functional outcome.