Craniomaxillofacial Trauma in Dogs-Part I: Fracture Location, Morphology and Etiology

Trends of regenerative tissue engineering for oral and maxillofacial reconstruction in veterinary medicine

Oral and maxillofacial (OMF) defects are not limited to humans and are often encountered in other species. Reconstructing significant tissue defects requires an excellent strategy for efficient and cost-effective treatment. In this regard, tissue engineering comprising stem cells, scaffolds, and signaling molecules is emerging as an innovative approach to treating OMF defects in veterinary patients. This review presents a comprehensive overview of OMF defects and tissue engineering principles to establish proper treatment and achieve both hard and soft tissue regeneration in veterinary practice. Moreover, bench-to-bedside future opportunities and challenges of tissue engineering usage are also addressed in this literature review.

Reverse Pedicle U-Shaped Palatal Flap: An Innovative Technique for Repair of Severe Caudal Palatal Defects in Two Dogs

An acquired palatal defect in dogs is a pathologic condition in which there is communication between the oral cavity and nasal cavities, maxillary recesses, or orbits. Many different causes exist and must be considered. Two dogs were presented for severe palatal defects secondary to a foreign body trapped between maxillary dental arches. Numerous techniques have been previously described to repair palatal defects, and the most appropriate choice is based on the clinical features of the defect and information obtained from advanced diagnostic imaging. Acquired palatal defects are not predictable in shape, size, and location; therefore, although the literature contains many different surgical techniques, these are not always reliable. The aim of this article is to describe an innovative surgical approach to repair severe acquired caudal palatal defects in two different dogs.

Normal variation of clinical mobility of the mandibular symphysis in dogs

Introduction

The primary objective of this retrospective study was to document the normal variation of clinical mobility of the mandibular symphysis in dogs, and evaluate possible associations with breed, bodyweight, age, sex, and skull morphology. Secondarily, the radiographic appearance of the mandibular symphysis and possible associations with the analyzed data were also evaluated.

Methods

Medical records of dogs that underwent anesthetic procedures for maxillofacial, oral and dental evaluation from April 2015 to December 2021 were included.

Results

567 dogs of 95 different breeds were included, with a total of 695 evaluations. Body weight ranged from 0.8 kg to 79 kg (median 14.4 kg) and age from 3 months to 16 years and 4 months (median 6 years and 9 months). Clinical mobility was evaluated under general anesthesia using a 0 to 3 scale, in lateromedial (LM) and dorsoventral (DV) directions. The symphysis was radiographically classified as being fused or open. The open symphyses were further radiographically divided in having parallel or divergent margins. At the time of the first evaluation DV mobility was 0 in 551 cases (97.2%) and 1 in 16 cases (2.8%). LM mobility was 0 in 401 cases (70.7%), 1 in 148 cases (26.1%) and 2 in 18 cases (3.2%). There was not a significant change in mobility over time for cases examined more than once (P= 0.76). All cases had an intraoral radiographic examination. 83.8% of the radiographs were included in the statistical analysis. Two symphyses (0.4%) were classified as fused and 473 (99.6%) as open, 355 (74.7%) having divergent margins and 118 (24.8%) parallel margins. Logistic regression models exploring factors that affected DV and LM mobility were statistically significant (P < 0.0001; P < 0.0001), with an increase in LM mobility predicting an increase in DV mobility, and vice versa. An increase in age and in bodyweight was associated with a decrease in mobility. There was no statistical difference in clinical mobility across specific breeds or sexes. Increased probability of a divergent symphysis and increased DV mobility was found to be associated with a brachycephalic conformation. The increase in LM mobility was comparatively higher in small brachycephalic breeds compared with larger brachycephalic breed.

Discussion

The majority of the cases showed little to no mobility of the mandibular symphysis and radiographically bony fusion can be rarely seen.

Prognostic indicators for feline craniofacial trauma: a retrospective study of 114 cases

Craniofacial traumatic injuries contribute significantly to the morbidity and mortality of domestic felines. Previous studies focused on feline craniofacial injuries have investigated the origin of injury, injuries sustained, and effectiveness of diagnostic tools. The aim of the study is to identify prognostic indicators for feline craniofacial trauma patients and determine their association with negative and positive outcomes. The Veterinary Committee on Trauma (VetCOT) Trauma Registry and Dentistry and Oral Surgery Case Logs were utilized to identify feline craniofacial trauma cases that were presented to Colorado State University's Veterinary Teaching Hospital between 2014 and 2020. Prognostic indicators evaluated included: etiology of injury, signalment (age and sex), the Modified Glascow Coma Scale (MGCS), Animal Trauma Triage (ATT) scores, craniofacial examination findings, diagnostic imaging technique, and injuries identified via imaging. Outcomes were determined via patient status upon discharge. Outcomes were grouped into the following categories: survival to discharge at initial presentation to CSU Urgent Care (SDIP), survival to discharge after injury treatment/repair by CSU DOSS or another specialty service (SDTX), euthanized due to grave prognosis at initial presentation (EUGP), euthanized due to financial limitations at initial presentation (EUF), and euthanized due to grave prognosis and financial limitations (EUGP + EUF). The continuous data was described using means and standard deviations. To determine the associations of various groupings of clinical signs and imaging findings with outcome a principal component analysis was performed. Patient sex, trauma etiology, cumulative MGCS and ATT scores on initial presentation and clinical signs on initial presentation were identified as prognostic indicators with intact males, vehicular and animal altercations, lower MGCS cumulative scores, higher ATT scores and the presence of altered mentation identified as negative prognostic indicators. Prognostic indicators for feline craniofacial trauma can be associated with outcomes and help guide clinical decision making.

Management of failed stainless steel implants in the oromaxillofacial region of dogs

Management of complications of fracture fixation in the oromaxillofacial (OMF) region may present a diagnostic and therapeutic challenge. While titanium and stainless steel implants have been utilized in successful fracture fixation in the OMF region, the use of titanium implants is preferred due to the superior intrinsic properties of titanium. Nonetheless, stainless steel materials are still used due to their availability and familiarity. In the present methods report, we describe our approach to the management of failed stainless steel plates and screws used to treat traumatic injuries in the OMF region. Furthermore, we exemplify our approach with five dogs that exhibited complications of stainless steel implants in the OMF region and their subsequent management. In those cases, all failed implants were removed. Reconstruction with a combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) and titanium implants was utilized in two cases while a mandibulectomy was performed in one case. Three cases required removal of the stainless-steel implant with no additional surgical therapy. We conclude that the success of treatment of failed stainless steel implants depends on the use of advanced imaging findings, appropriate antimicrobial therapy, as well as potentially regenerative reconstructive surgery.

Craniomaxillofacial trauma in immature dogs–etiology, treatments, and outcomes

Treatment of craniomaxillofacial (CMF) trauma in dogs often requires a multidisciplinary approach and a thorough understanding of the CMF anatomical structures involved. This retrospective study aimed to utilize computed tomography (CT) studies of immature dogs evaluated for CMF trauma and to describe common fracture locations, treatment modalities, and complications, as well as the fracture healing outcomes. The medical records and CT studies of 94 dogs under 1 year of age over a 13-year period were evaluated. The skeletal location of CMF fractures, as well as the severity of displacement and fragmentation of each fracture, was recorded. Case demographic data and trauma etiology were also recorded. Animal bites accounted for the majority of trauma (71.0%). The most likely bone or region to be fractured was the maxillary bones, followed by the molar region of the mandibles. Up to 37 bones or specific regions were fractured in any given patient, with an average of 8.8 ± 3.1 fractured bones or regions per dog. Rostral mandibular trauma was associated with intra-articular fractures of the temporomandibular joint (p = 0.016). Patients sustained concomitant injuries in 32% of the cases. Muzzle therapy was the main treatment performed for most dogs (53.2%), followed by soft tissue closure (47.9%) and selective dental extractions (27.6%). Healing complications were recorded in 71.6% of the dogs, with malocclusion being the most reported complication (55.2%), and associated with dentate mandibular jaw fractures (p = 0.05). The average number of complications per dog was 2.4. No statistically significant association was found between treatment modality and healing outcome. There was a positive correlation between the severity of fracture fragmentation and displacement and a negative healing outcome (all rho >0.7). Further treatment was required in 55.6% of the dogs. Additional dental extractions were performed in 77.7% of patients. Healing complications were common in the immature CMF trauma case. Thus, the need for a comprehensive assessment of the entire CMF region during the initial visit, as well as follow-up, preferably using CT or cone beam CT, is underscored.

Surgical Treatment and Outcome of Acquired Midline Palate Defects in Cats

Acquired midline palate defects (PDE) affect the hard palate and/or soft palate, and result from trauma, commonly falling from a height or being hit by a motor vehicle. Additional life-threating injuries and costs associated with the treatment may delay the surgical treatment. This retrospective study describes signalment, cause, and extent of the PDE, and treatment in 25 cats. In addition, the outcome of the surgical repair is described in 19 (76%) cats. All defects were repaired within 5 days of the injury. Twenty (80%) cats were 4 years of age or younger. The most common rostral extent of the PDE was to the level of the third premolar tooth (n = 8; 32%), incisor teeth (n = 7; 28%), and fourth premolar tooth (n = 5; 20%). The soft palate laceration was present in all cases. Surgical therapy was successful in all cases with follow-up. The most common techniques used for the closure of the hard palate defect were bilateral pedicle flaps with lateral releasing incisions (n = 8; 32%), direct apposition of the oral mucosa (n = 7; 28%), bilateral pedicle flaps with lateral releasing incisions and interquadrant splinting (n = 5; 20%), and unilateral pedicle flap with one lateral releasing incision (n = 4; 16%). A tension-free closure by direct apposition of the edges was possible for the soft palate laceration. No oronasal fistulae were identified at follow-up. The only complication was malocclusion. The interquadrant splinting was most often used for PDE extending to the rostral portion of the hard palate (p < 0.05). The cats that suffered postoperative malocclusion were significantly more likely to have sustained temporomandibular joint injury, underwent CT scan, or had a feeding tube placed before discharge. The results of this retrospective study indicate that the early treatment (within 5 days) of the acquired longitudinal defects in the midline of the hard and soft palates is highly successful.

Application of a bilateral temporal fascia free graft in a dog with multifragmented frontal sinus and nasal bone fracture

OBJECTIVE

To describe the use of temporal fascia free grafts to treat dorsal open comminuted frontal sinus and nasal fractures.

ANIMAL

One Belgian shepherd dog.

STUDY DESIGN

Case report METHODS: A 5-year-old spayed female Belgian shepherd was admitted with severe facial deformation due to trauma. A deep, 3 cm wide wound was present between the nose and the frontal sinus. No abnormalities were detected on neurological examination. On computed tomographic examination, comminuted open fractures of the frontal and nasal bones were associated with a severe depression of the dorsal wall and presence of bone fragments in the sinus cavities. Bone fragments were apposed with polydioxanone monofilament suture. Bilateral temporal fascia grafts were placed over the bone fragments.

RESULTS

The integrity of the frontal and nasal cavities, and the facial profile of the dog were restored. No short-term or long-term complications were observed after 4 months follow up.

CONCLUSION

The innovative combination of suture apposition of bone fragments and a temporal fascia free graft resulted in very satisfying long-term outcomes in a dog with open sinus and nasal bone fractures.

Titanium mesh osteosynthesis for the treatment of severely comminuted maxillofacial fractures in four dogs

INTRODUCTION

Major goals in maxillofacial fracture treatment include to restore the dental occlusion, stabilise the major skeletal supports, restore the contour of the face and achieve proper function and appearance of the face. Titanium is considered an optimal material for maxillofacial reconstruction due to its biocompatibility, high strength, minimal inflammatory reaction and minimal imaging artefact.

OBJECTIVES

To describe the clinical details, surgical technique, pre- and postoperative imaging and short- and long-term follow-up of severely comminuted maxillofacial fractures treated with titanium mesh and titanium screws in dogs.

MATERIALS AND METHODS

Retrospective short case series included four client-owned dogs with maxillofacial fractures. After appropriate medical stabilisation, preoperative CT examination of the head was obtained in all patients for evaluation of fracture configuration and surgical planning. The maxillofacial fractures were stabilised by titanium mesh osteosynthesis. Short- and long-term clinical and radiographic follow-ups were available for all dogs.

RESULTS

Proper dental occlusion and reconstruction of the anatomic buttresses was achieved in all cases. All dogs recovered uneventfully from the surgery and no complications were recorded on the long-term follow-up up to 43 months. Occlusion was maintained in all dogs, as well as excellent cosmesis of the midface.

CLINICAL SIGNIFICANCE

Titanium mesh osteosynthesis can achieve sufficient rigidity and lead to uncomplicated healing of severely comminuted maxillofacial fractures. This internal fixation method can be considered a valuable option to treat maxillofacial fractures in particular in cases of large bone defect and midface reconstruction.

Agreement of Magnetic Resonance Imaging With Computed Tomography in the Assessment for Acute Skull Fractures in a Canine and Feline Cadaver Model

Computed tomography (CT) is the imaging modality of choice to evaluate patients with acute head trauma. However, magnetic resonance imaging (MRI) may be chosen in select cases. The objectives of this study were to evaluate the agreement of MRI with CT in the assessment for presence or absence of acute skull fractures in a canine and feline cadaver model, compare seven different MRI sequences (T1-W, T2-W, T2-FLAIR, PD-W, T2^*-W, “SPACE” and “VIBE”), and determine agreement of four different MRI readers with CT data. Pre- and post-trauma CT and MRI studies were performed on 10 canine and 10 feline cadaver heads. Agreement of MRI with CT as to presence or absence of a fracture was determined for 26 individual osseous structures and four anatomic regions (cranium, face, skull base, temporomandibular joint). Overall, there was 93.5% agreement in assessing a fracture as present or absent between MRI and CT, with a significant difference between the pre and post trauma studies (99.4 vs. 87.6%; p < 0.0001; OR 0.042; 95% CI 0.034–0.052). There was no significant difference between dogs and cats. The agreement for the different MRI sequences with CT ranged from 92.6% (T2^*-W) to 94.4% (PD-W). There was higher agreement of MRI with CT in the evaluation for fractures of the face than other anatomic regions. Agreement with CT for individual MRI readers ranged from 92.6 to 94.7%. A PD-W sequence should be added to the MR protocol when evaluating the small animal head trauma patient.

Craniomaxillofacial Trauma in Dogs-Part II: Association Between Fracture Location, Morphology and Etiology

Treatment of craniomaxillofacial (CMF) trauma in dogs requires a thorough understanding of the CMF skeletal structures involved. The human medical literature has several examples of CMF trauma and fracture classification, including the classically described Le Fort fractures. The recent classification schemes require large studies using computed tomography (CT). In the veterinary medical literature, such studies are lacking. The aims of part II of this retrospective study were to use a large number of CT studies of dogs evaluated for CMF trauma to determine whether specific fracture locations in the CMF region occur concurrently, and whether trauma etiology influences fracture morphology. This information may then be used to form a fracture classification scheme in the future. The medical records and CT studies of 165 dogs over a 10-year period were evaluated. The skeletal location of CMF fractures as well as the severity of displacement and fragmentation of each fracture was recorded. Dogs' demographic data and trauma etiology were also recorded. Fractured portions of the mandible tended to occur with fractures of adjacent bones, with the major exception of symphyseal separation, which occurred simultaneously with fractures of the cribriform plate. Fractures of the maxillary bone were accompanied by many concurrent fractures affecting the majority of the midface, skull base, and cranial vault. When the zygomatic bone was fractured, the other bones comprising the orbit also tended to fracture. Fractures of the relatively superficially located frontal and nasal bones were often accompanied by fractures of the skull base. Fracture etiology influenced fracture morphology such that vehicular trauma resulted in a relatively higher number of severely displaced and comminuted fractures than did other trauma etiologies. This study provides examples of fractures that, when found, should prompt veterinarians to look for additional injuries in specific locations. In addition, it further highlights the need for thorough CT evaluation of the entire CMF region, even when clinically apparent fractures appear relatively superficial.