Modified Labial Button Technique for Maintaining Occlusion After Caudal Mandibular Fracture/Temporomandibular Joint Luxation in the Cat.

Maxillofacial trauma in cats often results in mandibular symphyseal separation in addition to injuries of the caudal mandible and/or temporomandibular joint (TMJ). Caudal mandibular and TMJ injuries are difficult to access and stabilize using direct fixation techniques, thus indirect fixation is commonly employed. The immediate goals of fixation include stabilization for return to normal occlusion and function with the long-term objective of bony union. Indirect fixation techniques commonly used for stabilization of caudal mandibular and temporomandibular joint fracture/luxation include maxillomandibular fixation (MMF) with acrylic composite, interarcade wiring, tape muzzles, and the bignathic encircling and retaining device (BEARD) technique. This article introduces a modification of the previously described "labial reverse suture through buttons" technique used by Koestlin et al and the "labial locking with buttons" technique by Rocha et al. In cases with minimally displaced subcondylar and pericondylar fractures without joint involvement, the labial button technique can provide sufficient stabilization for healing. Advantages of the modified labial button technique include ease of application, noninvasive nature, and use of readily available materials. The construct can remain in place for a variable of amount of time, depending on its intended purpose. It serves as an alternative to the tape muzzle, which is rarely tolerated by cats. This technique can be easily used in conjunction with other maxillomandibular repairs, such as cerclage wire fixation of mandibular symphyseal separation. The purpose of this article is to demonstrate a modified labial button technique for maintaining occlusion of feline caudal mandibular fractures/TMJ luxations in a step-by-step fashion.

Regenerating Mandibular Bone Using rhBMP--2: Part 2-Treatment of Chronic, Defect Non-Union Fractures.

OBJECTIVE: To describe a surgical technique using a regenerative approach and internal fixation for reconstruction of critical size bone defect non-union mandibular fractures. STUDY DESIGN: Case series. ANIMALS: Dogs (n = 6) that had internal fixation of defect non-union mandibular fracture. METHODS: In 5 dogs, the repair was staged and extraction of teeth performed during the initial procedure. After 21-98 days (mean, 27 days) pharyngotomy intubation and temporary maxillomandibular fixation were performed. Using an extraoral approach, a locking titanium miniplate was contoured and secured to the mandible. A compression resistant matrix (CRM) infused with rhBMP-2 was implanted in the defect. The implant was then covered with a soft tissue envelope followed by surgical wound closure. RESULTS: All dogs healed with intact gingival covering over the mandibular fracture site defect and had immediate return to normal function and correct occlusion. Hard-tissue formation was observed clinically within 2 weeks and solid cortical bone formation within 3 months. CT findings in 1 dog at 3 months postoperatively demonstrated that the newly regenerated mandibular bone had 92% of the bone density and porosity compared to the contralateral side. Long-term follow-up revealed excellent outcome. CONCLUSION: Mandibular reconstruction using internal fixation and CRM infused with rhBMP-2 is an excellent solution for the treatment of critical size defect non-union fractures in dogs.

Estudio histológico comparativo de la reparación ósea entre hueso alveolar y extra-alveolar en los cerdos sometidos a osteotomía con alta y baja velocidad, con refrigeración líquida / Comparative study of bone repair between alveolar and extra-alveolar bone in pigs subjected to osteotomy at low speed and high speed with liquid refrigeration

Introducción. Teniendo en cuenta que el proceso de reparación ósea en los cerdos se muestra en una mayor proximidad entre las variables histológicas estudiadas en comparación con otros modelos biológicos, el presente estudio tenía como objetivo evaluar el proceso histológico de la reparación ósea de osteotomías realizadas en huesos alveolares y extra-alveolar, utilizando instrumentos rotatorios con refrigeración líquida. Material y método. Dieciocho cerdos Large White con peso comprendido entre 20 y 25Kg fueron divididos en tres grupos de seis animales cada uno, con cada grupo formado por tres animales para evaluar la reparación de osteotomías con baja y alta velocidades en el hueso alveolar y tres en área extra-alveolar en los períodos de estudio de 7, 14 y 28 días. Resultados. Se observó que en el hueso alveolar en los tiempos post-operatorio de 14 y 28 días, los mejores resultados de reparación fueron en las osteotomías realizadas con baja velocidad, mientras que en el período post-operatorio de siete días, los resultados con alta velocidad fueron ligeramente mejores tanto en áreas alveolares como extra-alveolares. Para la metodología utilizada, no se encontraron diferencias estadísticamente significativas en el proceso de reparación ósea alveolar y extra-alveolar. Conclusiones. El proceso de reparación, por medio de análisis microscópico en la región alveolar y extra-alveolar, son similares con mejores resultados observados en osteotomías hechas con taladros en baja velocidad en los tiempos de catorce y veintiocho días y en el post-operatorio de siete días, los resultados con taladros de alta velocidad y la refrigeración fueron ligeramente mejores. Los trabajos de investigación utilizando cerdos como modelo animal son perfectamente viables(AU)

Introduction. Taking into account the bone repair process in pigs has shown a greater similarity among the histological variables studied compared to other biological models, the present study has as its aim to evaluate the histological bone repair process of osteotomy performed on alveolar and extra-alveolar bones, using drilling tools with liquid refrigeration. Material and method. Eighteen Large White pigs weighing between 20 and 25 Kg were divided into three groups of six animals in order to evaluate the osteotomy repairs with low and high speed in the alveolar bone and threes in the extra-alveolar area, study periods of 7, 14 and 28 days. Results. It was observed that in the alveolar bone at the postoperative times of 14 and 28 days, the best repair results were in the osteotomy performed with low speed, while in the 7 day postoperative period, the results with high speed were slightly better, in alveolar areas as well as extra-alveolar areas. There no statistically significant differences between the alveolar and extra-alveolar bone repair process. Conclusions. The repair process, by means of microscopic analysis in the alveolar and extra-alveolar areas, are similar with better results observed in osteotomies performed with low speed drills in the 14 and 28 day study periods, and at 7 days postoperative the results with high speed drills and refrigeration were slightly better. Research works using pigs as an animal model are perfectly viable(AU)

Maxillomandibular external skeletal fixation in five cats with caudal jaw trauma.

Five cats with caudal jaw injuries including mandibular ramus fractures, temporomandibular luxation/subluxation and temporal bone fractures were managed with external skeletal fixation to provide open-mouth maxillomandibular fixation. Three of five cats were able to eat orally during the period of fixation, whereas two cats with jaws fixed in a suboptimal position were dependent on oesophagostomy tube nutrition. Fixation was well tolerated and was maintained for 21 to 42 days. All cats were eating normally and had good jaw function at follow-up (mean 39 months, range 7 to 71 months).

Maxillomandibular circular external skeletal fixation for repair of bilateral fractures of the caudal aspect of the mandible in a dog.

OBJECTIVE: To describe the novel use of circular external skeletal fixation (CESF) for repair of bilateral fractures of the caudal aspect of the mandibles. STUDY DESIGN: Clinical report. ANIMALS: A 5-month-old female Newfoundland. METHODS: A 2-ring CESF was used to immobilize the mandible relative to the maxillae. RESULTS: Anatomic dental occlusion and reduction of the right hemimandible were achieved with mild malalignment of the left hemimandible. Fracture healing occurred within 20 days. Transient epistaxis and reduced temporomandibular joint range of motion occurred at the time of fixator removal but normal use of the mandible was reported 6 months postoperatively. CONCLUSIONS: CESF effectively immobilized the mandible permitting rapid fracture healing with minimal morbidity. CLINICAL RELEVANCE: Maxillomandibular CESF may represent a simple, effective option for the management of challenging fractures involving the caudal aspect of the mandible.

Finite element modeling for development and optimization of a bone plate for mandibular fracture in dogs.

This study aimed to develop a plate to treat fractures of the mandibular body in dogs and to validate the project using finite elements and biomechanical essays. Mandible prototypes were produced with 10 oblique ventrorostral fractures (favorable) and 10 oblique ventrocaudal fractures (unfavorable). Three groups were established for each fracture type. Osteosynthesis with a pure titanium plate of double-arch geometry and blocked monocortical screws of free angulation were used. The mechanical resistance of the prototype with unfavorable fracture was lower than that of the favorable fracture. In both fractures, the deflection increased and the relative stiffness decreased proportionally to the diminishing screw number The finite element analysis validated this plate study, since the maximum tension concentration observed on the plate was lower than the resistance limit tension admitted by the titanium. In conclusion, the double-arch geometry plate fixed with blocked monocortical screws has sufficient resistance to stabilize oblique fractures, without compromising mandibular dental or neurovascular structures.

Oral and maxillofacial reconstruction in a cat using wire and acrylic.

A 15-month-old DSH cat was presented with facial deformity secondary to multiple oral and maxillofacial fractures after being struck by an automobile. Multiple wires and dental acrylics were used for fracture repair.