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Temporomandibular joint ankylosis in cats and dogs. A report of 10 cases
Abstract
Temporomandibular joint (TMJ) ankylosis is characterized by difficulty or inability to open the mouth. The ankylosis may be articular ('true') or extra-articular ('false'). Clinical signs, radiographic studies, treatment and follow-up are presented in a retrospective study involving five cats and five dogs. The findings were compared with TMJ ankylosis in humans. CT imaging with three-dimensional reconstruction proved to be of great value in determining the extent of the abnormalities and helped with preoperative planning. Articular TMJ ankylosis occurred in six animals and extra-articular TMJ ankylosis was found in the other four cases. In three cats and in three dogs, the TMJ ankylosis was trauma related; the remaining patients were diagnosed with a tumour. Resection of ankylosing tissue in false ankylosis or gap arthroplasty in true ankylosis was successful in all of the trauma induced cases. In the two cats, with tumour related ankylosis, the ankylosis was caused by an osteoma and resection had a good prognosis, whereas the two dogs had to be euthanatized.
... Clinical findings include weight loss, vocalizing or whining while trying to eat, malocclusion, skull malformation, halitosis and unkempt haircoat owing to reduced self-grooming. [3][4][5][6] TMJA results from intra-(true TMJA) and extraarticular (false TMJA or pseudoankylosis), bony, fibrous or fibro-osseous tissue proliferation from traumatic, neoplastic or degenerative processes. Diagnosis of TMJA is based on the patient's history, clinical signs and diagnostic imaging. ...
... The etiology of TMJA in dogs and cats can vary, but the consensus in the literature is that trauma is the leading cause. 1,2,4,6,20 Young patients in particular have a tendency to develop rapidly progressing unilateral or bilateral TMJA after trauma. This is possibly due to the intense healing capacity of damaged bone tissue at a young age, which leads to exuberant fibrous and bone tissue formation in the TMJ region. ...
... This complication has been related to the inability to remove all abnormal fibrous and bone tissue owing to the proximity of vital neurovascular structures. 4,16 Although radiographic images can be used in the initial screening of patients affected by TMJA, CT and CBTC are undoubtedly the gold standard techniques in determining affected anatomical structures, assessing the extent and quality of abnormal tissue and for surgical treatment planning. 10,12,[32][33][34] The main limitations of plain radiography include overlap of bone structures and low image resolution vs CT and CBCT images. ...
Case series summary
Three cats affected by unilateral temporomandibular joint ankylosis underwent segmental mandibulectomy, while one cat with bilateral ankylosis underwent right temporomandibular joint gap arthroplasty and left segmental mandibulectomy. Minimal intraoperative complications were linked to the segmental mandibulectomies in the cases reported. All cats recovered their ability to open the mouth, and the vertical range of motion was unaltered during the postoperative period. Mandibular drift and dental malocclusion were the main postoperative complications related to the segmental mandibulectomies.
Relevance and novel information
Surgical excision of ankylotic tissue at the temporomandibular joint region may be technically challenging and associated with severe iatrogenic trauma of surrounding tissues. The results of this case series suggest that middle or caudal segmental mandibulectomy is a safe, feasible and effective surgical procedure to treat unilateral temporomandibular ankylosis in cats and could be considered as an alternative surgical technique to surgical excision of ankylotic tissue at the temporomandibular joint.
... Τα περιστατικά οστεώματος που έχουν αναφερθεί σε γάτες και ειδικά αυτά που αφορούν τη γναθοπροσωπική περιοχή είναι λίγα σε αριθμό, ενώ φαίνεται να μη συνδέονται με την ηλικία, καθώς έχουν περιγραφεί σε γάτες από ενός μέχρι 23 ετών. 1,8,9,12 Σε αντίθεση με τον άνθρωπο, στον οποίο συνήθως τα οστεώματα είναι περιφερικά, 11 στη γάτα μια σχετική μελέτη αναφέρει παρόμοια ποσοστά μεταξύ των δύο μορφών του οστεώματος. 1 Στον ακριβή προσδιορισμό των ορίων, αλλά και στη διαφοροποίηση του τύπου του οστεώματος σημαντικό ρόλο διαδραματίζουν οι τεχνικές της απεικονιστικής διαγνωστικής και ειδικά η υπολογιστική τομογραφία. Η υπολογιστική τομογραφία προσφέρει πληροφορίες κυρίως για τη σύσταση, τη δομή και τα περιφερειακά όρια του οστεώματος, ενώ η μαγνητική τομογραφία για τις αλλοιώσεις των γειτονικών μαλακών ιστών. ...
... Η υπολογιστική τομογραφία προσφέρει πληροφορίες κυρίως για τη σύσταση, τη δομή και τα περιφερειακά όρια του οστεώματος, ενώ η μαγνητική τομογραφία για τις αλλοιώσεις των γειτονικών μαλακών ιστών. 1,2,8,12 Στο παρόν περιστατικό η υπολογιστική τομογραφία παρείχε στη χειρουργική ομάδα τις απαραίτητες πληροφορίες για την εξαίρεσή του. Με βάση τα απεικονιστικά ευρήματα τέθηκε η υποψία παρουσίας οστέωματος (πιθανότατα περιφερικού τύπου) ωστόσο η οριστική διάγνωση τέθηκε μετά από την ιστοπαθολογική εξέταση της μάζας. ...
... There are only a few reported cases of skull osteomas in the cat which seem to be unrelated to age, as the reported age distribution is between 1 and 23 years. 1,8,9,12 In contrast to human, where osteomas are primarily peripheral, 11 a study conducted in cats, reports same prevalence for the two types. 1 In order to accurately define the extent of the lesion and differentiate the type of the osteoma, diagnostic imaging, particularly the computed tomography is of great importance. Computed tomography can provide the clinician with information concerning the composition, the structure and the extent of the mass, while magnetic resonance will reveal potential soft tissue involvement. ...
A seven-year-old cat was admitted due to dysphagia caused by a mandibular tumor. Upon examination, a round, non-painful, firm mass which was attached to the underly-ing bone was revealed. Radiography and computed tomography of the mandible were performed. The mass involved the area between the last premolar tooth and the angu-lar process, up to the neck of the condyloid process. Based on the findings of the com-puted tomography, a tentative diagnosis of a peripheral osteoma was made. Caudal mandibulectomy was performed and the mass was excised en bloc. Histopathological examination confirmed the diagnosis of an osteoma. Recovery was uneventful; the ani-mal was able to eat quite normally a week after surgery and is symptom-free one year later
... [1][2][3] Unilateral TMJA (Figure 1) is characterized by the partial or complete inability to open the mouth due to intra-or extra-articular fibrous, bony or fibro-osseous tissue proliferation from traumatic, developmental, inflammatory or neoplastic origin. 2,[4][5][6] Other conditions that can cause progressive inability to open the mouth are masticatory muscle myositis and severe ear disease. 2 Although it is known that fractures affecting the joint are the most common cause of TMJA in veterinary patients, there is no consensus regarding the pathophysiology of TMJA. 2,3,7,8 In humans, TMJA may be related to a postoperative infection of the joint or calcification of hemarthrosis from an extra-articular hematoma. ...
... Its diagnosis must be suspected during the awake physical examination and confirmed by a diagnostic imaging test. 5,9,12 Veterinary patients affected by TMJA demonstrate a partial or complete inability to open the mouth, malocclusion, skull malformation, weight loss, vocalizing or yowling while trying to eat, halitosis and unkempt haircoat because of reduced self-grooming. 2,5,11 Radiographic projections of the head have been routinely used for the initial evaluation of temporomandibular joint (TMJ) disorders in dogs and cats. ...
... 5,9,12 Veterinary patients affected by TMJA demonstrate a partial or complete inability to open the mouth, malocclusion, skull malformation, weight loss, vocalizing or yowling while trying to eat, halitosis and unkempt haircoat because of reduced self-grooming. 2,5,11 Radiographic projections of the head have been routinely used for the initial evaluation of temporomandibular joint (TMJ) disorders in dogs and cats. Cross-sectional imaging techniques such as CT and, more recently, cone beam CT (CBCT) have been considered the gold standard diagnostic imaging techniques for evaluating the TMJ bony structures. ...
Objectives
Temporomandibular joint ankylosis (TMJA) is the partial or complete inability to open the mouth due to intra- or extra-articular fibrous, bony or fibro-osseous tissue proliferation. Surgical procedures such as gap arthroplasty, condylectomy or wide extra-articular osteotomy have been recommended to treat this condition; these techniques are challenging, time-consuming and have been occasionally associated with postoperative recurrence, severe periarticular neurovascular iatrogenic trauma and death. Segmental mandibulectomy had previously been recommended as an alternative option for unilateral TMJA, but the location of mandibulectomy and extent of bone removal from the mandible region have not been mentioned in the literature. This study aimed to validate the area of the mandibular body (rostral, middle or caudal) and amount of bony tissue that should be osteotomized during a segmental mandibulectomy for treatment of unilateral TMJA in cats.
Methods
In this block study, 30 cadaver heads of domestic shorthair cats were randomly divided into three groups of 10 specimens each based on the mandibular region that would undergo segmental mandibulectomy (rostral, middle and caudal). The size of the removed mandibular segment and pre- and postoperative vertical range of mandibular motion were compared for statistical purposes.
Results
A significant statistical difference was observed between the pre- and postoperative vertical range of mandibular motion between the rostral, middle and caudal segmental mandibulectomies ( P <0.001). The mean postoperative recovered range of mandibular motion for the rostral, middle and caudal segmental mandibulectomies was 50.4%, 81.9% and 90.4%, respectively.
Conclusions and relevance
The caudal segmental mandibulectomy showed the highest postoperative vertical range of mandibular motion. The removal of a minimum of 1.2 cm of the caudal mandibular body was required to achieve nearly full recovery of presurgical mouth opening in the specimens of this study. The caudal segmental mandibulectomy may eliminate the risk of iatrogenic periarticular neurovascular damage inherent to more invasive surgeries performed at the temporomandibular joint area. When performed unilaterally, the caudal segmental mandibulectomy is a viable surgical alternative that may show a similar outcome to other surgical techniques.
... Cats most commonly are presented at a young age with a known history of maxillofacial trauma, typically secondary to falling, having been bitten by a dog, or vehicular trauma (10,11). If there is no known history of trauma, diagnostic imaging is often suggestive of historic trauma. ...
... Other differential diagnoses include infection (i.e., osteomyelitis or retrobulbar disease), a congenital malformation, or less likely, neoplasia (1, 2, 6-8, 12, 13). Depending on age at the time of trauma, there may be discordant maxillofacial growth or abnormal tooth eruption (1,4,10). Oral examination of these cats is often unrewarding due to the limited ability to open the mouth. ...
... TMJ ankylosis can be seen in human pediatric patients due to trauma during the birthing process, and less commonly due to an underlying congenital condition (1,7,8,13). Some authors have suggested that traumatic injury of the TMJ in young human and animal patients can result in increased severity of ankylosis due to the excellent healing capacity noted in younger patients and due to the development of an exuberant bony callus (4,10,12). In this report, documented injuries included high-rise falls, dog attacks, and vehicular trauma. ...
Temporomandibular joint (TMJ) ankylosis is defined as fibrous or bony fusion of the mandibular head of the condylar process and the mandibular fossa of the squamous part of the temporal bone. Ankylosis of the TMJ may be intraarticular, extraarticular, or both. The objective of this report is to describe the surgical planning, technique, and outcome of gap arthroplasty for extensive TMJ ankylosis in cats. Client-owned cats (n = 7) were examined clinically and surgical planning included the use of cone-beam computed tomography (CBCT) and tridimensional (3D) printed models. In six of the seven cats, temporary tracheostomy intubation was required. Gap arthroplasty included zygomectomy, coronoidectomy, condylectomy, as well as fossectomy (removal of the mandibular fossa of the temporal bone) and was performed using a piezosurgical unit. In all seven cats, gap arthroplasty was performed without surgical complications. In addition, a clinically acceptable mouth opening was achieved in all cases. However, a noticeable mandibular instability was observed. Medium-term follow-up demonstrated acceptable quality of life with one case of recurrence of ankylosis requiring repeated bilateral surgery, and a second case with recurrence of ankylosis not requiring surgical intervention at the time of manuscript preparation. We concluded that TMJ gap arthroplasty in cats is a salvage procedure indicated in cases of severe intraarticular and extraarticular ankylosis. Diagnostic imaging by means of CBCT and 3D printing are essential for precise surgical planning. The use of a piezosurgical unit allows for safe and precise ostectomy. Clinically, despite the resulting mandibular instability, appropriate prehension of food and water was possible.
... Pseudoankylosis ensues secondary to osseous or fibrous callus formation between the bone and soft tissue (9,10). Pseudoankylosis of the craniomaxillomandibular structures often develop from traumatic injury in dogs and is reported anecdotally (10)(11)(12)(13)(14)(15). Pseudoankylosis can be caused by infection or neoplasia, but these are very sporadically diagnosed. ...
... The most common neoplasms of the temporomandibular joint region in dogs are osteosarcoma and multilobular tumour of bone (5,16,17). A developmental aetiology appears to be rare (10)(11)(12)(13)(14)(15)18). ...
... Few studies involving temporomandibular joint disorders in dogs have been published, some of these with general focus on true ankylosis and pseudoankylosis (5,6,13,14,22). The number of cases with pseudoankylosis and ankylosis in the present study is in agreement with prior results of a higher occurrence of pseudoankylosis than true ankylosis (5). ...
Objective:
To describe the clinical features and results of treatment of true ankylosis and pseudoankylosis of the temporomandibular joint in dogs.
Methods:
This study was a retrospective case series. Ten client-owned dogs that were presented for inability to open the mouth or a severely decreased range of motion of the temporomandibular joint were included. Information on the surgical procedures performed and the perioperative complications were documented. Three-dimensional printing of the skull was performed in four dogs.
Results:
Two dogs were diagnosed with temporomandibular joint ankylosis and seven dogs with pseudoankylosis. One dog had evidence of combined temporomandibular joint ankylosis and pseudoankylosis. Of the seven dogs with pseudoankylosis, six had an osseous fusion involving the zygomatic arch and mandible. Surgical treatment was performed in nine dogs and a revision surgery was needed in one dog. Follow-up ranged from five months to eight years (mean: 48.6 months). Eight out of nine dogs that were treated surgically regained the ability to open their mouth, but six dogs never regained a fully normal temporomandibular joint range of motion.
Clinical significance:
Temporomandibular joint ankylosis and pseudoankylosis are uncommon in the dog. Surgical treatment for temporomandibular joint ankylosis or pseudoankylosis in dogs is a successful option and carries a prognosis dependent on patient-specific abnormalities. Computed tomography complemented with three-dimensional printing is valuable for understanding the extent of abnormalities and for preoperative planning.
... It was demonstrated that TMJ trauma is the most common cause of TMJ ankylosis. In a retrospectively study of 10 cases of TMJ ankylosis in cats and dogs, TMJ trauma was documented as the major etiology factor in 60% of cases (Maas and Theyse, 2007 ). The finding of trauma being the cause of TMJ ankylosis is similar to a previous study (Sullivan, 1989; Mark et al., 1996; Meomartino et al., 1999; Okumura et al., 1999). ...
... CT images also produce three-dimensional images from computer software. These three-dimensional images can allow a diagnosis as well as a determination of the prognosis, treatment planning, and estimation of the treatment outcome (Maas and Theyse, 2007). CT images are limited when making a diagnosis of fibrous TMJ ankylosis. ...
... The treatment of TMJ ankylosis in cats and dogs used a condylectomy, coronoidectomy and complete resection of the ankylotic block. Most cases were treated successfully with gap arthroplasty including a condylectomy (Tomlinson and Presnell, 1983; Sullivan, 1989; Mark et al., 1996; Meomartino et al., 1999; Maas and Theyse, 2007). In an experimental study of the functional and anatomic changes after gap arthroplasty using an animal model, it was reported gap arthroplasty for TMJ ankylosis did not restore the TMJ functionally and histologically to the preexisting state (Matsuura et al., 2001). ...
An approximately 7-year-old 1.7kg, female Siamese cat with a history of a malocclusion and an inability to open its mouth was referred the Animal Medical Center, Chonbuk National University. The cat had shown signs since it was adopted four years earlier but the cause was not determined. The mandible was deviated 2 mm to left, the mouth could be opened only 2 mm and attempts to open the jaws caused considerable pain. Radiographs indicated new bone formation and a loss of joint space in the right temporomandibular joint(TMJ). 3-dimensional CT showed bony fusion and bone thickness in the right TMJ. The physical, 3-dimensional CT and radiographic examinations revealed right TMJ ankylosis. Under general anesthesia, surgical treatment was per - formed to remove the ankylosis block with subsequent interpositional arthroplasty using a temporalis myofascial flap. The patient showed distinct improvement in both the articular functionality and clinical signs.
... Using 3DVR provides excellent images of all the bone components of the joint, focusing on the shape and spatial relationships among the different bone structures [1,17,18]. It also helps to determine the extension of anomalies to plan for the best surgical management [29]. However, as some artifacts have also been observed when studying 3DVR images [7], it remains mandatory to compare 3DVR images with standard plane images. ...
... Until now, 3DVR images of TMJ have only been briefly studied when focusing on different alterations in craniomandibular osteopathy, dysplasia [6], mandible luxation [6], post-traumatic ankylosis [23], sarcoma in the caudal portion of mandible [24], mandible osteomyelitis [25], fractures secondary to septic arthritis or osteomyelitis [25] or even to fit the site of puncture of a joint [31]. These studies showed lateral and rostrolateral views of the TMJ, but only Mielke et al. 2017 [29] showed ventral images of the TMJ of dogs of different breeds, relating its anatomical positions with tympanic bullae. However, no detailed studies employing 3DVR images to describe the medial, ventral, ventrolateral and caudoventral aspects of the TMJ and its relationship with other bone structures have been found in the literature. ...
Simple Summary
The temporomandibular joint (TMJ) of dogs is a bilateral joint mainly used for chewing, and subsequently, an area where pathologies are frequently seen. Computed tomography (CT) represents a very important imaging modality used to diagnose TMJ diseases in dogs. A three-dimensional representation of CT images created by a volume rendering method (3DVR) could improve our understanding of the alterations in this joint. In this study, we assessed 3DVR as an ancillary method for the description and diagnosis of TMJ pathologies in dogs.
Abstract
Based on computed tomography (CT) images, volume rendering was used to obtain a three-dimensional representation of data (3DVR). The aims of this study included: describing the bone anatomy of the temporomandibular joint (TMJ) of dogs; comparing the TMJs of each dog by skull type and age; comparing 3DVR images with three-standard-plane CTs; assessing soft tissues adjacent to the TMJ and assessing pathological cases. Multidetector computed tomography scans of bilateral TMJs of 410 dogs were observed. From a ventral view, slight displacements in the positions of the skulls were seen, whereas from a caudal view, differences in amplitude of the articular space were observed. Dolichocephalic and mesaticephalic dogs showed more similar TMJ features than brachycephalic dogs. The shape of the TMJ bones were irregular in dogs under 1 year old. The 3DVR images related to the three-standard-plane CT improved the overall comprehension of the changes in the articular space amplitude and condylar process morphology. The fovea pterygoidea, mandibular fossa and retroarticular process were perfectly shown. A better spatial situation of adjacent soft tissues was obtained. The 3DVR represents an ancillary method to the standard-plane CT that could help in the understanding of the anatomy and diagnoses of different pathologies of the TMJ in dogs.
... 4,5 Ankylosis of the TMJ is an uncommon condition that can occur after trauma. [22][23][24] In a recent study of patients with TMJ disorders, only about 6% had ankylosis, and of these, only half were associated with previous TMJ fracture. 23 Difficulty opening the mouth is a sequela that can take months to occur and become clinically evident. ...
... For this reason, stabilization methods that allow some lower jaw movement, such as muzzling or labial button technique, are recommended. 21,22 Owners of patients with trauma to the TMJ, caudal mandible and maxilla, or zygomatic arch should be instructed to continuously monitor the ability to open the mouth. ...
This case report describes diagnosis, treatment, and outcome of maxillofacial trauma in a 9-week-old shih tzu. In addition to an open left mandibular body fracture and a right condylar process fracture, there were several relatively stable and minimally displaced right maxillary fractures. The torn soft tissues associated with the left mandibular body fracture were sutured closed, and a tape muzzle was placed. Due to sufficient fracture healing at the 2-week recheck examination, the tape muzzle was removed. The 6-week reexamination confirmed continued healing and recovery. Anesthesia was performed at the 5.5-month reexamination when the dog was 8 months old, revealing the presence of persistent deciduous teeth, linguoverted, malformed, and partially erupted permanent teeth, and asymmetric skeletal malocclusion (in addition to the breed-specific mandibular mesioclusion). Persistent deciduous teeth and linguoverted and malformed permanent teeth were extracted to allow for normal opening and closing of the mouth without traumatic occlusion. Long-term follow-up is recommended in juvenile dogs with maxillofacial injuries in order to prevent, recognize, and treat dental complications resulting from the trauma.
... Although CT examination may not identify all soft tissue lesions, it is still superior to radiography in providing soft tissue information, and it has proved to be of great value in these cases. 5 Excision arthroplasty is the recommended treatment for these conditions, with the elimination of ankylosed tissue. 4,6 Mandibular drift and recurrence of the ankylosis have been reported after excision arthroplasty, 2,7-9 and a study performed in feline cadavers suggests that unilateral condylectomy causes a significant increase of laterolateral lower jaw movement, which could have an impact on occlusion. ...
... Early rehabilitation after TMJ surgery is advisable by feeding small amounts of food various times a day and encouraging mouth opening by manual manoeuvres or playing with toys. 5 In this case, a programme of daily manual mouth opening and feeding soft food every 2 h for 1 week was used. ...
Case summary
A 2-year-old, intact female domestic longhair cat was referred for surgical treatment after diagnosis of closed jaw locking secondarily to right temporomandibular joint ankylosis and left pseudoankylosis. The animal underwent successful surgical management with bilateral excision arthroplasty followed by interposition of a temporal superficial myofascial flap. Immediately after surgery, the full range of lower jaw movement was achieved and normal occlusion was maintained. Ankylosis did not recur in the 1 year postoperative follow-up period.
Relevance and novel information
A temporal myofascial flap could be considered as interposition material after temporomandibular joint arthroplasty to avoid postoperative re-ankylosis and mandibular drift. The main advantages of this flap are its autogenous origin, and the ability to maintain separation between the two bones, preserve mobility and disrupt new bone formation.
... 4,5 Studies of TMJ disorders in dogs and cats are lacking and have been limited to those involving fractures resulting from trauma, dysplasia, and ankylosis. [6][7][8][9][10][11] Temporomandibular joint disorders are often debilitating and frequently require medical or surgical treatment. In humans with TMJ disorders, the most common pathological change is degenerative joint disease, also known as osteoarthritis or osteoarthrosis, which is generally caused by displacement of the articular disk or some other intra-articular derangement. ...
... The finding that dogs and cats with TMJ disorders generally have multiple joint abnormalities was intriguing. Many studies 6,[8][9][10][11] involving TMJ disorders in dog and cats have been individual case reports or focused only on the clinical signs of affected patients. In the present study, we retrospectively evaluated CT images obtained from all patients that underwent CT evaluation of the skull during the study period, which allowed us to identify TMJ abnormalities even in patients that did not have clinical signs of disease. ...
Objective:
To describe CT findings in dogs and cats with temporomandibular joint (TMJ) disorders.
Design:
Retrospective case series.
Animals:
41 dogs and 17 cats.
Procedures:
Medical records and CT images of the skull were reviewed for dogs and cats that were examined at a dentistry and oral surgery specialty practice between 2006 and 2011.
Results:
Of 142 dogs and 42 cats evaluated, 41 dogs and 17 cats had CT findings consistent with a TMJ disorder. In dogs, the most common TMJ disorder was osteoarthritis; however, in most cases, there were other TMJ disorders present in addition to osteoarthritis. Osteoarthritis was more frequently identified at the medial aspect rather than the lateral aspect of the TMJ, whereas the frequency of osteoarthritic involvement of the dorsal and ventral compartments did not differ significantly. In cats, fractures were the most common TMJ disorder, followed by osteoarthritis. Clinical signs were observed in all dogs and cats with TMJ fractures, dysplasia, ankylosis, luxation, and tumors; however, only 4 of 15 dogs and 2 of 4 cats with osteoarthritis alone had clinical signs.
Conclusions and clinical relevance:
Results indicated that TMJ disorders were frequently present in combination. Osteoarthritis was the most common TMJ disorder in dogs and the second most common TMJ disorder in cats. Computed tomography should be considered as a tool for the diagnosis of TMJ disorders in dogs and cats with suspected orofacial disorders and signs of pain. (J Am Vet Med Assoc 2013;242:69-75).
... In cats, temporomandibular joint ankylosis is a rare condition which usually results from trauma as well as developmental, inflammatory and neoplastic changes (8,(12)(13)(14)(15)(16)(17)(18). An ankylosis is classified as either intracapsular (true) or extracapsular (false), and its treatment consists of a condylectomy or resection of periarticular structures on the affected side, or a combination of both procedures (1,3,4,10). ...
... Although it is a rare condition, intra-articular lesions may result in temporomandibular joint ankylosis (3,8,10,(13)(14)(15)(16)(17)(18). The treatment consists of a condylectomy and resection of periarticular structures on the affected side and cats can tolerate this procedure without malocclusion (1)(2)(3)(4)(5)10). ...
Objective:
To evaluate cause, location, treatment, and the clinical outcome of traumatic temporomandibular joint (TMJ) lesions and TMJ ankylosis in cats.
Methods:
Cats with TMJ injuries were included in this study. Lesions were classified as luxations, fractures of the condylar process, and intra-articular temporal bone fractures. Signalment, cause and type of injuries, treatment methods, clinical outcome, complications and joint ankylosis were assessed and evaluated statistically.
Results:
Temporomandibular joint lesions were observed in 82 of 161 cats with maxillofacial injuries. One hundred forty-nine TMJ lesions were determined in 112 joints. Falling was the most common cause and fractures of the condylar process were the most common types of injuries. Isolated TMJ injuries and caudal TMJ luxations were mainly caused by falling. Condylectomy was used in ankylosis, chronic luxation, reluxation and in two cases with multiple TMJ lesions. Ankylosis was observed in 10.97% of cases and was generally observed in fracture combinations of condylar process and mandibular fossa (χ² = 8.52; p <0.05). No significant relationship between age and development of ankylosis (χ² = 3.995; p >0.05) was found.
Conclusion:
In contrast to previous studies, traumatic TMJ lesions were observed in a considerable amount of cats with maxillofacial injuries, and fractures of the condylar process were the most common type. Lesions caused by falling were mostly simple, whereas vehicular trauma caused more complicated lesions. Ankylosis did not appear as a rare condition. Any cat with TMJ injury is susceptible to the development of ankylosis.
... Two dogs and two cats were included in the study. Clinical presentations and diagnosis features observed align with those documented in previously published literature (21,22). Surgical approach was generally similar, but each case is different in terms of specific features of the lesions presented; ...
Three-dimensional (3D) printed models can improve the understanding of the structural anatomic changes in cases of temporomandibular joint ankylosis and pseudoankylosis leading to closed jaw locking. Their use in pre-surgical planning and intraoperative guidance has been reported, contributing to the predictability and success of these surgery procedures, which can be quite complex, especially in small animal patients. The use and production of 3D tools and models remain challenging and are so far limited to institutions with high (economical and human) resources. This study aims to propose simplified workflows using open-source software to facilitate an in-house 3D printing process. To illustrate this, three cases of temporomandibular joint ankylosis and one of pseudoankylosis were reviewed, where in-house 3D printed models were used for client communication and surgical management. The 3D models were segmented from computed tomography and printed via stereolithography. They were used to support discussion with clients (n = 4), to allow surgeons to pre-surgical plan and practice (n = 4) and for intraoperative guidance during surgery (n = 2). Surgical cutting guides were produced in one case to improve precision and define more accurately osteotomy lines. It is essential to consider the initial time and financial investment required for establishing an in-house 3D printing production, particularly when there is a need to produce biocompatible tools, such as surgical cutting guides. However, efficient and streamlined workflows encourage the integration of this technology, by accelerating the printing process and reducing the steep learning curves, while open-source software enhances accessibility to these resources.
... The temporomandibular joint (TMJ) is a synovial joint between the mandibular condyle and the articular fossa of the temporal bone (Mohan et al., 2012). TMJ ankylosis is characterised by restricted mandibular movements with reduced mouth opening, and its anaesthetic management is challenging due to the limited visualisation of the larynx (Maas & Theyse, 2007;Shashidharreddy et al., 2017). ...
A 6‐month‐old, 2.9‐kg, male, Korean short hair cat was referred for inadequate mouth opening (4 mm), and condylectomy was scheduled for ankylosis of the left temporomandibular joint. Retrograde intubation via the cricothyroid membrane was planned since direct visualisation of the larynx was not possible. In dorsal recumbency, the cricothyroid membrane was punctured with an 18‐gauge needle, and a J‐tip guidewire, inserted via the needle, was advanced and identified at the mouth. A 6‐Fr truncated feeding tube was inserted from the mouth to the cricothyroid membrane along the guidewire. The guidewire was removed, and the tip of the feeding tube was advanced as an anterograde guide to the inner trachea. Subsequently, an endotracheal tube was inserted along the feeding tube. Capnography was used to confirm correct intubation. Condylectomy was performed on the left temporomandibular joint, and the patient recovered from anaesthesia uneventfully. Retrograde intubation is less invasive than tracheostomy or cricothyroidotomy, and the cricothyroid membrane has been suggested as a suitable site for guidewire insertion in humans and dogs. However, when resistance is encountered during the advancement of endotracheal tube using the traditional technique without the anterograde guide, it may be difficult to distinguish where the resistance occurred leading to damage or oesophageal displacement in cats with relatively fragile airway. This report suggests that retrograde intubation via the cricothyroid membrane can be performed in cats with limited visualisation of the larynx, and an anterograde guide following the retrograde wire could reduce the potential damage or oesophageal displacement.
... 20 In a report concerning dogs and cats treated for TMJa, 10% temporary mild facial paralysis was observed, but the surgery was not performed with piezosurgery. 21 When facing TMJa, the normal anatomy is often distorted with severe bone remodelling and fusion. None of the cats with TMJ fractures had concurrent ankylosis. ...
The aim of this study was to describe and share employment of piezoelectic surgery and 3D printed pre‐operative surgical planning model in cat affected by temporomandibular joint ankylosis (TMJa). A 3‐year‐old neutered male domestic shorthair cat presented feeding problem was submitted for a CT scan of the head in order to investigate clinical TMJa. A 16‐slice multidetector CT scanner was used. CT scan revealed a misshapen, rounded right condylar process, with irregular and reduced TMJ space. A right condylectomy through piezoelectric surgery was performed. In order to plan the best surgical approach, a 3D printed model was used prior the surgery to easy identify the ideal angulation for condylectomy and during the surgery to verify the proper extent of the osteotomy. At 6‐month follow‐up the range of mouth opening is close to normal.
... The primary etiologies of ankylosis in cats and dogs include trauma and tumors [4]. The etiologies of ankylosis in humans include infection, trauma, dental treatment, TMJ disorders (rheumatoid arthritis, DJD), tumors, oral care, drugs, radiotherapy, chemotherapy, congenital malformations, and miscellaneous disorders [1]. ...
Background:
Ankylosis in the temporomandibular joint (TMJ) is known to have various etiologies in veterinary medicine. We observed a case of fibrous ankylosis of the TMJ in a newly imported rhesus monkey (Macaca mulatta).
Case presentation:
Moderate to severe attrition was found in the middle labial portion of the left maxillary canine. No tenderness around the jaw was detected in the physical examination. The WBC count, CRP level, rheumatoid factor level, and other parameters were normal. Irregularity in the joint surface was observed in both TMJs in the radiographic and computed tomographic examinations, but the left TMJ presented more severe irregularity. It was determined that the removal of the locked portion of the left canine would alleviate the case of lockjaw and allow intubation with an endotracheal tube. Canine tooth crown reduction was performed for both canine teeth. The mouth opening distance slightly (approximately 5 mm) increased up to 20 mm. We concluded that the attrition of canine teeth was not the reason for lockjaw and ankyloses originating from TMJ disease. Fibrotic synovial tissue and joint surface irregularity were observed by necropsy. The presence of fibrocartilage in most areas of the TMJ was confirmed by histology. The diagnosis was fibrous ankylosis of the TMJ associated with DJD.
Conclusions:
To the best of our knowledge, this is the first report of degenerative joint disease of the TMJ in a rhesus monkey with fibrous ankylosis of the TMJ.
... Additional emerging causes which could be added to the list are myopathies of masticatory muscles (Evans et al. 2004). Atrophy of this group of muscles leads to a restriction of the animal's ability to open the mouth (Maas and Theyse 2007). This process usually takes quite a long time to evolve and is without indication of pain. ...
Temporomandibular ankylosis, even though considered to be of a relatively rare emergence, can be encountered in day-today clinical practice. Most cases follow a typical, if not identical anamnesis pattern. The background of mechanical difficulties manifestation is associated with some trauma. The animals usually suffer a severe blow to the head, leading to a gradual development of the defect, which unfortunately most owners are not aware of, or claim not to be. This case report describes a typical incidence of post traumatic ankylosis of the temporomandibular joint (TMJ). The patient suffered a blow to the head at the age of 4 months, the clinical aftermath of which was a gradual difficulty in opening the mouth. A CT examination revealed the extent of damage in the region of the zygomatic arch, affecting also the corresponding TMJ. For this particular case, a surgical intervention was the only course of treatment, meaning the resection of arcus zygomaticus and the TMJ. The procedure was scheduled to be performed 14 days post the CT examination. Due to the fact that the changes were located only on the lateral surface of the TMJ, the plan was to resect and remove the affected area only, with the medial part of the TMJ left intact and in position. The joint capsule was then sutured. This approach proved to be very beneficial and effective in the outcome of the surgery and in aiding in the overall comfort of the patient.
... Subluxationen und Luxationen des Kiefergelenks kommen ebenfalls vor (2,34). Neben traumatisch bedingten Läsionen stellen Osteomyelitiden (35), Tumoren und Ankylosierungen (28,34) weitere Indikationen für die bildgebende Diagnostik des Kiefergelenks dar. Des Weiteren wurden rassebedingte morphologische Veränderungen des Kiefergelenks festgestellt. ...
Zusammenfassung
Gegenstand und Ziel: Um den Einfluss unterschiedlicher Aufnahmeparameter auf die Bildqualität zu untersuchen, wurden die Kiefergelenke (KG) von Hunden und Katzen mittels Mehrschicht-Computertomographie (MSCT) dargestellt. Weiterhin sollte geprüft werden, ob Größenunterschiede des KG die Darstellbarkeit kleiner Gelenkstrukturen beeinflussen. Material und Methoden: Die KG von zwei Hunden und zwei Katzen wurden mit der MSCT unter Variierung von RöhrenstromZeit-Produkt, Matrix, Auflösungsmodus, Schichtdicke und Rekonstruktionsintervall untersucht. In einer Blindstudie bewerteten drei Untersucher die Bildqualität anhand der Kriterien “Bildkontrast”, “Knochenstruktur”, “Ortsauflösung”, “Beurteilbarkeit des Gelenkspalts” und “Artefakte” anhand einer vierstufigen Skala. Ergebnisse: Die Merkmale “Ortsauflösung” und “Beurteilbarkeit des Gelenkspalts” verdeutlichen den Einfluss der Objektgröße. Hinsichtlich der Bildqualität ergab sich beim KG der Hunde eine um 0,5 bis 1,5 Grad bessere Bewertung als beim kleineren KG der Katzen. Die mit ultrahochauflösender Untersuchungstechnik erzeugten CT-Bilder wurden bezüglich “Ortsauflösung” und “Knochenstruktur” um ein Grad besser bewertet als die mit einem hochauflösenden Protokoll erstellten Aufnahmen. Eine Dosisabhängigkeit war nicht nachweisbar. Schlussfolgerungen und klinische Relevanz: Die Darstellung kleiner Gelenkstrukturen wird entscheidend durch die Ortsauflösung der CT-Bilder beeinflusst. Daher sollten eine enge Schichtkollimation, ein kleines Messfeld und eine hochauflösende Rekonstruktionsmatrix eingesetzt werden. Veränderungen knöcherner Strukturen des KG sind damit zuverlässig darstellbar, dessen Weichteilgewebe können jedoch beim Kleintier nicht differenziert werden. Die Ergebnisse sind prinzipiell auf andere MSCT übertragbar, doch sollte eine Anpassung der technischen Parameter erfolgen.
... Replacement of the mandibular condyle with preservation of the temporal component of the TMJ has not been described. Cats maintain good clinical function following condylectomy for various nonneoplastic diseases, such as articular and extra-articular ankylosis, [47][48][49] despite postoperative evidence of mild malocclusion, 48 and so it is possible that a prosthetic mandibular condyle or total alloplastic TMJ replacement may not be required for mandibular reconstruction following total mandibulectomy. However, a cadaveric biomechanical study 50 revealed significant differences in occlusion following unilateral mandibular condylectomy in clinically normal cats, so studies of the biomechanical and clinical importance of the necessity of the mandibular condyle are required to optimize mandibular prosthesis design. ...
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.
... However, because of the shape and angulation of the condylar process of the mandible, in dogs and cats, the main mandibular movement is in vertical dimensions (opening and closing the mouth), with little lateral range of motion (ROM) (3,4). Mandibular ROM may be hampered or limited by a number of conditions affecting the intrarticular or extrarticular structures, such as true or false TMJ ankylosis, ostheoarthirtis, fracture, osteomyelitis, bone neoplasia, retrobulbar masses, neuromuscular diseases and trismus (e.g., masticatory myositis, tetanus), craniomandibular osteopathy, and others (5)(6)(7)(8)(9)(10)(11)(12). Early detection of reduced ROM may therefore allow for early diagnosis of these diseases. ...
The main movement of the temporomandibular joint of dogs and cats is in vertical dimensions (opening and closing the mouth). An objective evaluation of the vertical mandibular range of motion (vmROM) may favor early diagnosis of a number of conditions affecting the joint mobility. vmROM, corresponding to the maximum interincisal opening, was measured in 260 dogs and 127 cats anesthetized between June 2011 and April 2015 because of oral or maxillofacial problems and procedures. Animals with a known history of or having current diseases considered to hamper mandibular extension were excluded from the study. Dogs were divided into four subgroups, based on body weight: subgroup 1 (≤5.0 kg, 51 dogs), subgroup 2 (5.1–10.0 kg, 56 dogs), subgroup 3 (10.1–25 kg, 66 dogs), and subgroup 4 (>25.1 kg, 87 dogs). The mean vmROM of all dogs was 107 ± 30 mm (median 109, range 40–180); in subgroup 1 was 67 ± 15 mm (median 67, range 40–100), in subgroup 2 was 93 ± 15 mm (median 93, range 53–128), in subgroup 3 was 115 ± 19 mm (median 116, range 59–154), and in subgroup 4 was 134 ± 19 mm (median 135, range 93–180). The mean vmROM of the cats was 62 ± 8 mm (median 63, range 41–84). Correlations between vmROM, age, sex, and body weight were evaluated. In dogs, vmROM did not correlate with age, and in cats a weak positive correlation was found. vmROM and body weight were positively correlated in both populations, except dog subgroup 2. Overall, mean vmROM and body weight were significantly higher in male than in female, both in dogs and in cats. However, vmROM did not differ between sexes in any of the canine subgroups, and only in subgroup 4 male dogs were significantly heavier than females. Evaluation of vmROM should be incorporated into every diagnostic examination as it may be valuable in showing changes over time for every single patient.
... Subluxationen und Luxationen des Kiefergelenks kommen ebenfalls vor (2,34). Neben traumatisch bedingten Läsionen stellen Osteomyelitiden (35), Tumoren und Ankylosierungen (28,34) weitere Indikationen für die bildgebende Diagnostik des Kiefergelenks dar. Des Weiteren wurden rassebedingte morphologische Veränderungen des Kiefergelenks festgestellt. ...
Temporomandibular joints (TMJs) of dogs and cats were examined with multislice computed tomography (MSCT) using different technical scan parameters in order to investigate their impact on image quality. Another aspect was to analyze whether size differences of the TMJ affect the display of small joint structures.
The TMJs of two dogs and two cats were examined using MSCT. Scan parameters were varied including tube current, scan matrix, resolution mode, slice thickness, and reconstruction increment. Three observers being blinded with respect to the used scan parameters independently assessed the image quality in terms of "contrast resolution", "bone structure", "spatial resolution", "evaluation of the joint space", and "artefacts" according to a 4-point scale.
The criteria "spatial resolution" and "evaluation of the joint space" emphasize the influence of the size of the TMJ. The image quality of the TMJ of the dogs was evaluated superior (by 0.5 to 1.5 points higher graded) compared to the smaller ones of the cats. In terms of "spatial resolution" and "bone structure" the images of an ultra high resolution technique achieved a higher evaluation level (scoring one point superior) compared to the images created by a high resolution protocol. The tube current did not significantly influence the image quality in any of the pictures.
The display quality of small structures of the TMJ is dependent on the spatial resolution of the CT images. Therefore, a thin slice collimation, a small field of view, and a high resolution reconstruction matrix should be used. Under those aspects subtle alterations of bone structure of the TMJ can be reliably detected. The soft tissue structures of the TMJ can not be visualized with MSCT in small animals. In principle, the results can be applied to any other MSCT-scanner. However, adjustments of the technical parameters may be still necessary.
Craniomandibular osteopathy (CMO) is a proliferative, self-limiting, non-neoplastic disease of growing dogs characterised by excessive new bone formation on the skull and mandible. The radiographic findings of CMO are well described; however, limited reports of the computed tomographic (CT) appearance are available. This paper aims to characterise the spectrum of CT findings that can occur with CMO. The study is retrospective, descriptive, multicenter, and includes 20 cases. Age at presentation ranged from 6 weeks to 12 months, with no sex predisposition. Scottish terriers were overrepresented (65%); other breeds included Cairn terrier, Jack Russell terrier, Staffordshire bull terrier, labrador retriever, golden retriever, akita and Slovakian rough-haired pointer (one of each breed). Terrier breeds represented 80% (16/20) of the patient cohort. Mandibular osteoproliferation was present in all patients (marked in 80%, bilateral in 95%), affecting the rostral mandible in 25%, body in 85%, and ramus in 80%. Tympanic bulla osteoproliferation was present in 60% (12/20) of patients (all marked, bilateral in 75%). Cranial osteoproliferation (frontal, parietal, temporal, occipital bones or maxilla, or combinations of them) was present in 90% (18/20) of patients (40% marked, 27% moderate, 33% mild). Nasopharyngeal narrowing was seen in all 12 patients with tympanic bulla osteoproliferation (67% marked, 27% moderate) and caused nearly complete occlusion in two of them. External ear canal stenosis was seen in 55% (11/20) of patients (63% marked, 37% moderate, all bilateral). Temporomandibular joint (TMJ) impingement was suspected in 83% (10/12) of patients with marked tympanic bulla osteoproliferation (75% bilateral). Osteolysis with a moth-eaten pattern was seen in the mandible of 10/20 dogs, the calvarium of 5/20 dogs, and the maxilla of 1/20 dogs (5%). Lymphadenomegaly (mandibular and medial retropharyngeal) was found in 15/20 patients (70% mild, 30% moderate). The most severe CT changes were seen in Scottish terriers. CT allows for detailed characterisation of the bony changes associated with CMO, including the effects occurring secondary to osteoproliferation surrounding the tympanic bullae such as TMJ impingement, external ear canal stenosis, and nasopharyngeal narrowing. Osteoproliferation affecting the cranium and the presence of osteolysis were seen more frequently in this study than previously reported in CMO.
The temporomandibular joint (TMJ) ligaments play crucial roles in its function or dysfunction. The objective of this study was to describe the macro and microscopic morphology of these ligaments in domestic pigs, aiming to: (1) expand knowledge about the species; (2) provide anatomical references for advancing veterinary therapy and utilizing pigs as animal models in craniofacial research. Heads of young Sus scrofa domesticus were dissected to identify TMJ ligaments. Fragments of these ligaments were collected and processed for subsequent histological analysis with Haematoxylin and eosin staining. The results were qualitatively described. Pigs exhibited a TMJ reinforced by three individualized capsular ligaments: a lateral ligament, attaching to the ventral margin of the zygomatic process of the temporal bone and the lateral margin of the mandibular neck; a caudomedial ligament, attaching to the retroarticular process of the squamous part of the temporal bone and the caudomedial margin of the mandibular neck and a caudolateral ligament, attaching to the ventral margin of the base of the zygomatic process of the temporal bone and the caudal margin of the mandibular neck. The lateral ligament exhibited a greater constitution of dense irregular connective tissue, while the caudomedial and caudolateral ligaments showed a greater constitution of dense regular connective tissue. It is concluded that the TMJ of pigs presents one more ligament than horses, cattle, dogs, cats and what has been described for pigs themselves. We believe these results may contribute to the improvement of veterinary clinical and surgical therapy overall, as well as provide essential morphological information for a better interpretation and application of interspecies results in craniofacial research using pigs as an experimental model, as in the case of humans.
Fully understanding the complex mechanical function of temporomandibular joint (TMJ) cartilage and the compositional and structural organization that underlie it is a persistent challenge. Changes to composition, structure, and mechanics take place in naturally occurring disease in humans and canines as well as in disease models, such as in pigs. This study combined histology, Fourier transform infrared (FTIR) microscopy, Fast Fourier transform (FFT), and confocal elastography to quantify the relationship between the microscale composition, structure, and shear mechanics of porcine, canine, and human TMJ cartilage. All three species had distinct zonal mechanics and similarly high stiffness of 105~106 Pa in the hypertrophic zone. Notably, porcine tissue had a thick, compliant fibrous zone (~ 200 µm) (G* < 104 Pa) that was absent in canine and human tissue. The hypertrophic zone of all three species had high proteoglycan content, while the surface regions showed higher collagen content and fiber orientation. Small changes (two-fold) in composition led to large changes (twenty-fold) in modulus. Structural orientation of the fibers showed that high fiber orientation led to more compliant tissue mechanics while the angle of orientation was not predictive of the shear mechanics. The relationship between local composition, structure, and mechanics were similar in all three species. Despite this similarity, the immature pigs used most frequently in disease models have a very thick compliant surface region, the presence of which is likely to alter the degenerative process.
Pseudoankylosis of the temporomandibular joint is infrequent in veterinary practice and mostly seen secondary to trauma. This case report describes the surgical treatment of a 1‐year old, male, entire lurcher that presented with progressive lateral deviation of the muzzle to the left and decreased vertical mandibular range of motion of 6‐month duration. There was no history of trauma, no pain on palpation and complete loss of temporomandibular joint movement, even under sedation. Computed tomography investigation showed a left‐sided temporomandibular pseudoankylosis with osseous fusion between the zygomatic arch and mandible. Surgical excision of the ankylosed bone was performed and achieved an initial 5 cm interincisal gap. The surgical site healed, with no complications reported. Re‐examination at 4 weeks revealed good vertical mandibular range of motion with interincisal gap of approximately 5 cm. At 9 months post‐operatively, the dog had maintained good vertical mandibular range of motion and was able to eat normally, pant and hold large toys.
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.
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.
The tooth's pulp resides in the pulp cavity which includes the pulp chamber located in the crown and root canal located in the root. Painful stimuli from the oral environment also travel to the pulp through the dentinal tubules. The pulp is contained within a solid, unyielding chamber with limited blood supply. An uncomplicated crown fracture occurs when the loss of dental hard tissue extends into the dentin without exposing the pulp. The goal of endodontic treatment is to return teeth which have diseased pulp to pain‐free function. Zinc oxide–eugenol is cement that acts as a sealer between the gutta percha and root dentin. Mineral trioxide aggregate is composed of calcium and silicate. Ethylenediaminetetraacetic acid is available in both liquid and gel. The International Standards Organization sets normalization from one manufacturer to another regarding lengths and widths of flutes, taper, relationship between successive sizes. The mandibular symphysis is a joint which can separate when traumatized.
This study was performed to report etiology, clinical presentation, and outcome of mandibular fractures in immature dogs treated with non-invasive or minimally invasive techniques. Immature dogs diagnosed with mandibular fractures from 2001 to 2016 were included in this study. Diagnosis of the mandibular fracture was achieved by oral examination and diagnostic imaging in the anesthetized dog. Twenty-nine immature dogs with 54 mandibular fractures were selected. Within the mandibular body, the regions of the developing permanent canine and first molar teeth were most commonly involved (46.4% and 35.0%, respectively). Within the mandibular ramus, 53.8% of the fractures were located in its ventral half, and 38.5% in the condylar process. Muzzling was applied in 72.4% of the dogs. All dogs had clinical healing with resolution of signs of pain and recovery of mandibular function. Mean time for clinical healing was 21 ± 9 days. Age of the dog and duration of muzzling were significantly associated with the time needed for clinical healing. In immature dogs, fractures of the mandibular body occur most commonly in the regions of the developing permanent canine and first molar teeth, while fractures of the mandibular ramus are most commonly found in its ventral half and the condylar process. Non-invasive or minimally invasive management of mandibular fractures in immature dogs carries a good prognosis regarding clinical healing and recovery of mandibular function. Dogs should be monitored for the development of dental abnormalities and/or skeletal malocclusion until permanent teeth have erupted and jaw growth is completed.
This study reports the gape angle (vertical temporomandibular joint range of motion for mouth opening) in conscious and anesthetized dogs. Mouth opening was reported as an angle in this study. Additionally, conscious and anesthetized measurements were compared to see if the state of anesthesia affected this measurement in asymptomatic patients. This prospective study evaluated 165 anesthetized dogs. Patients were placed in 1 of 2 groups: dental patients or non-dental patients. Only patients who were reported by owners to be asymptomatic for oral pain were included in the study. All dogs that met inclusion criteria had the maxillary length and interincisal distance measured. There was no difference (p = 0.590) between the mean (+/-SD) gape angle of conscious 44.0 o (+/- 4.1+ o ) and anesthetized patients 43.9 o (+/- 3.9 o ). No difference was seen in the gape angle between dental (44.2 o ) and non-dental patients (43.2 o ) (p = 0.183), or between conscious (43.8 o ) and anesthetized patients (43.7 o ) (p = 0.610). This study suggests that a consistent gape angle of 44 o exists in dogs not exhibiting overt signs of oral pain and the gape angle is easy to measure in conscious patients and may be a useful tool during routine physical examination to identify patients with restricted range of motion. Immediate clinical application of this information can be used to monitor progress of treated patients affected by disorders that cause a decreased gape angle.
Ankylosis and pseudoankylosis are not common clinical entities and typically occur following oral and/or maxillofacial trauma. Patients with ankylosis or pseudoankylosis are likely to be presented with gradually worsening inability to open the mouth. Computed tomography (CT) is recommended as the imaging modality, as these disorders require appropriate characterization and understanding of the involved structures prior to surgical planning. Surgical treatment depends on the extent and location of the ankylosis and may involve condylectomy or gap arthroplasty for temporomandibular joint (TMJ) ankylosis and coronoidectomy with or without zygomectomy for pseudoankylosis.
Practical relevance
Skull trauma in cats, which includes fractures of the mandible and maxilla, as well as temporomandibular joint (TMJ) conditions, is frequently encountered in general practice.
Clinical approach
Head trauma requires immediate attention and the initial approach should be focused on stabilisation of the patient and evaluation of the major body systems, including respiratory and cardiovascular assessment, and neurological and ophthalmic examination. The head, oral occlusion and the patient’s ability to open and close the mouth should be carefully evaluated. Once the cat is stable enough for anaesthesia, diagnostic imaging is essential to assess for skull injuries. Radiography may be helpful, although some conditions may be difficult to visualise due to soft tissue and bony structure superimposition. CT is a more sensitive technique for detecting skull injuries.
Treatment goals and techniques
A variety of stabilisation techniques have been described in the feline patient, and repair goals focus on restoration of the animal’s oral function, while ensuring adequate dental occlusion, minimal invasiveness and morbidity, and pain relief. Surgical repair of mandibular and maxillary fractures may variously involve interdental wiring, interarcade wiring or suture, use of interfragmentary wires, plate and screw fixation, external skeletal fixation and use of dental acrylic. Decision-making with regard to treatment options depends on dental occlusion, type and location of the fracture, fracture stability and pain.
Aim
This review, directed at general practitioners working with cats, describes the relevant anatomy of the feline skull, the most common mandibular, maxillary and TMJ conditions, and their recommended management.
Temporomandibular joint (TMJ) ankylosis is an uncommon clinical entity in human and veterinary medicine. However, the condition is severely debilitating and is life-limiting if not treated. This study sought to characterize the intra- and extra-articular features of naturally occurring TMJ ankylosis in cats. TMJs from client-owned
cats (n ¼ 5) that underwent bilateral TMJ gap arthroplasty were examined and compared with TMJs from healthy, age-matched feline cadavers (n ¼ 2) by cone-beam computed tomography (CBCT), microcomputed tomography (mCT) and histologically. Features of bilateral intra- and extra-articular ankylosis compounded by degenerative joint lesions were identified radiographically and histologically in all affected cats. Features of TMJ ‘true’ ankylosis included variable intracapsular fibro-osseous bridging, degeneration of the disc and the articular surfaces, narrowing of the joint space and flattening of the condylar process of the mandible. Extra-articular features of TMJ ankylosis included periarticular bone formation and fibroosseous bridging between the mandible, zygomatic arch and coronoid process. In addition, subchondral bone loss or sclerosis, irregular and altered joint contours and irregularly increased density of the medullary bone characterized the degenerative changes of the osseous components of the TMJ. Complex radiological and histological features of both ankylosis and pseudoankylosis were identified that clinically manifested in complete inability to open the mouth.
The temporomandibular joint (TMJ) is a feature that distinguishes mammals from other vertebrates and to a lesser or greater degree have similar anatomic features (J Musculoskelet Neuronal Interact, 3:391–394, 2003). Specifically, the head of the mandible and the squamous temporal bone are covered by a thin fibrocartilage layer and separated by a disc that bisects the joint into two noncommunicating compartments. However, despite these general anatomic similarities, the TMJ does exhibit profound functional differences across mammals, which are evolutionary adaptations to the species-specific demands placed on the joint.
Oral pathology is considered present when a departure from normal occurs that is sufficient to cause signs or symptoms. This chapter covers conditions of oral cavity other than dental lesions, congenital and developmental issues, traumatic lesions, and tumors/cysts. Feline Calicivirus (FCV) replicates primarily in the oropharynx, and it is likely that it has a role in chronic gingivostomatitis and caudal mucositis. Hematological disorders have oral symptoms, such as anemia due to blood loss, shock or an iron deficiency causing pale mucous membranes that are slow to heal. Located at the back of the pharynx on either side, the tonsils will often not be visible in their crypts, though the presence of everted tonsils is a frequent observation in brachycephalic airway obstruction syndrome (BAOS). The temporomandibular joint (TMJ) can be impacted by trauma, skeletal abnormalities, dysplasia, inflammation, and tumors. Hypercementosis is an increase in the deposition of cementum customarily along the root surface of the tooth.
In cats, traumatic separation of the mandibular symphysis is most common, but dogs present more frequently with mandibular body fractures. Postoperative complications are more common with mandibular than with maxillary fractures. Preoperative complications include airway obstruction and brain injury, and malocclusion is the main intraoperative complication. Nonunion is a possible postoperative complication, as well as temporomandibular joint (TMJ) disease (luxation, ankylosis), which can develop later on. Animals with a traumatic TMJ luxation without fractures show an excellent prognosis after closed reposition. The TMJ should always be examined when dental occlusion is affected or problems exist to open or close the mouth. Fractures of the TMJ can heal by bony union or as a pain-free functional non-union although osteoarthritis or ankylosis may develop, necessitating a condylectomy. Maxillary-mandibular composite fixation (MMF) with a circular external skeletal fixator (ESF) has been described in a dog for the successful treatment of bilateral caudal mandibular fractures.
A three years, seven-month-old male entire Labrador retriever was referred with a one-month history of pain when yawning and eating. CT revealed a 20×10×10 mm mass in the region of the left caudal zygoma. CT-guided biopsy results identified a florid periosteal reaction but were otherwise inconclusive. Surgery was performed to resect the left caudal zygoma via the temporomandibular joint. Further histopathological results confirmed completely resected osteogenic osteosarcoma with narrow margins. No other treatment modalities were pursued. The dog remained free from clinical signs until 28 months following surgery when local tumour growth and thoracic metastases were diagnosed.
Objective:
To describe the use of two-dimensional computer-assisted tomography (CT) with three-dimensional (3D) reconstruction in the diagnosis and planning of surgical treatment of a case of false ankylosis of the temporomandibular joint.
Case report:
A young European Shorthaired cat was presented with the complaint of inability to eat and open its jaws. A CT scan with 3D reconstruction allowed visualization of the lesion which was causing extra-articular ankylosis of the temporomandibular joint. Surgery was performed to resect an osseous lesion of the zygomatic arch, thus freeing the temporomandibular joint. Postoperative physical therapy was initiated immediately following surgery, and then carried out by the owner with a one year follow-up. Clinical examination of the cat was performed during regular office visits (at 1 month and 3 months following surgery), which allowed objective assessment of postoperative recuperation. At the end of a year, the owners reported that the cat had maintained sufficient jaw opening without any signs consistent with chronic pain.
Conclusion:
Computed tomography scan with 3D reconstruction allowed planning of the surgical correction of extra-articular ankylosis of the temporomandibular joint, and in this case condylectomy was avoided, since temporomandibular joint range-of-motion was maintained.
Practical relevance:
Maxillofacial and traumatic dentoalveolar injuries can cause pain and inflammation, and reduce function of the mouth, impacting a cat's quality of life. Many traumatically induced feline fractures have been reported to involve the mandible or skull and, in cats with maxillofacial trauma, traumatic dentoalveolar injuries are particularly prevalent. Traumatic dentoalveolar injuries can also often be found in otherwise healthy cats.
Clinical challenges:
Some traumatic dentoalveolar injuries require emergency treatment; timely recognition and managment is therefore important for achieving the optimal outcome. Multiple approaches exist for the management and repair of maxillofacial traumatic injuries. However, those for traumatic dentoalveolar injuries may be more limited.
Audience:
This review is aimed at feline and general practitioners, as well as veterinarians with expertise in dentistry.
Evidence base:
The authors draw on their clinical experience and evidence from the literature, where appropriate, to produce an overview of foundation guidelines. It is hoped that this will serve as a stimulus for deeper consideration as to what constitutes 'best practice' principles for cats with traumatic dentoalveolar and maxillofacial injuries.
A 3 mo old female Airedale terrier presented with decreased range of motion of the temporomandibular joint (TMJ), which was first recognized at weaning. Computed tomography (CT) revealed abnormal, bilateral ossification of the soft tissues extending from the region of the tympanic bullae to the medial aspect of the angular process of each mandible. Those ossified structures most closely approximated the location of the lateral pterygoid muscles. The ossified structures were present at presentation and initially manifested as complete ossification on the right side. The condition progressed to complete bilateral ossification by 3 yr of age. The mandibular condyles associated with the temporomandibular joints were malformed. The patient had severe mandibular distoclusion with deviation of the mandible to the left. The left mandibular cheek teeth were positioned in a caudal cross bite. A single treatment of manual stretching and breakdown of the ossified muscle of mastication by placement of tongue depressors within the oral cavity resulted in no increase in TMJ range of motion as measured by the incisal opening. This is the first reported case of spontaneous false ankylosis of the TMJ in an Airedale terrier.
The minute anatomy of the temporomandibular joint (TMJ) is of great clinical relevance in cats owing to a high number of lesions involving this articulation. However, the precise anatomy is poorly documented in textbooks and scientific articles. The aim of this study was to describe, in detail, the TMJ anatomy and its relationship with other adjacent anatomical structures in the cat. Different anatomical preparations, including vascular and articular injection, microdissection, cryosection and plastination, were performed in 12 cadaveric cats. All TMJ anatomical structures were identified and described in detail. A thorough understanding of the TMJ anatomy is essential to understand the clinical signs associated with TMJ disorders, to locate lesions precisely and to accurately interpret the results in all diagnostic imaging techniques.
Investigation of temporomandibular joint (TMJ) disease requires a clear diagnostic image, which can be challenging to obtain using conventional radiography. The aim of this study was to compare five different oblique radiographic views with the head in lateral recumbency, assessing the clarity of visualization of the normal TMJ anatomy. The views under investigation were the laterorostral-laterocaudal oblique at a 10° and 20° rotation of the head ("nose-up" view), laterorostral-laterocaudal oblique with a rostrocaudal X-ray beam angulation of 10° and 20°, and a parallax view with the beam centered over C2 and collimated to include the TMJ region, using the divergence of the X-ray beam to project the TMJs separately on the radiograph. The views were performed on both TMJs of thirty canine cadavers and were graded independently by experienced and inexperienced observers. Grading was performed on the mandibular fossa, condylar process, joint space, retroarticular process, and the overall TMJ, and was based on a four-point scale. Mean grades for each component and for the overall joint were compared for each observer and each projection. Mean grades were significantly (P < 0.05) higher for the "Nose-up" projections than the angled beam or parallax projections, as was interobserver agreement, and both observers showed significantly higher (P < 0.05) mean grades for the 20(o) "Nose-up" angulation than the 10(o) "Nose-up" angulation. These results suggest that a latero 20(o) rostral-laterocaudal oblique gives the best representation of the anatomy of the TMJ of the dog of the projections assessed, and should be considered when investigating clinical cases of TMJ disease.
In magnetic resonance imaging (MRI) the image quality is considerably affected by the coil used, particularly when small structures are examined. The purpose of this study was to determine which coil provides the best scanning results for imaging of the temporomandibular joint (TMJ) of dogs and cats.
MRI investigations were performed using a standard human knee coil and an 8-cm-diameter surface coil with a low-field MRI-system (field strength 0.5 T). TMJs of two dogs and two cats were examined. The scan protocol consisted of T1-weighted spin echo (T1W/SE), T2-weighted turbo spin echo (T2W/TSE), a proton density-weighted sequence (PDW) (slice thickness: 3 mm each), and gradient echo sequences (slice thickness: 1-1.5 mm) in the sagittal plane. Three observers independently compared the features "contrast resolution", "bone structure", "spatial resolution", and "signal-to-noise ratio" (SNR) using a 5-point scale. Investigators were blinded with respect to the coils used.
Approximately 50% of the images obtained by the use of the surface coil were rated superior in comparison with the knee coil in terms of the features "contrast resolution", "bone structure", and "spatial resolution". In approximately 50% of the MRI-images no differences in the ratings were seen. With respect to the criterion "signal-to-noise ratio" 90% of the images acquired with the surface coil were rated better. In 5% of the images an identical quality was recorded. The surface coil proved to be superior both in dogs and cats.
Display quality of small structures of the TMJ is dependent on the spatial resolution of the MR images. Therefore, a dedicated coil and a small field of view (FOV) should be used. Results reveal that low-field MRI is able to display subtle anatomic structures of the TMJ in dogs and cats. In principle, the results can be transmitted to other MRI-systems. However, to generate valid scan protocols it is necessary to adapt scan parameters and coil selection specifically.
Objective —To describe clinical features of oral and maxillofacial osteomas in cats.
Design —Retrospective case series.
Animals —7 cats with oral or maxillofacial osteoma or both.
Procedures —Medical records were reviewed for information on signalment, history, clinical signs, physical examination findings, diagnostic imaging findings, results of serum biochemical analyses and histologic testing, surgical procedures performed, and perioperative complications. Outcome was determined on the basis of follow-up telephone interviews of owners.
Results —Cats ranged from 1 to 23 years of age. Clinical signs were observed in 5 cats and were attributed to the presence of the mass. Diagnostic imaging (radiography and computed tomography) and histologic examination confirmed the diagnosis of osteoma. Three cats were euthanatized; 1 cat was treated by mandibulectomy, 1 was treated by maxillectomy, and 2 were treated by debulking. At the time of follow-up at least 1 year after surgery, all 4 treated cats were alive, with owners reporting an acceptable quality of life.
Conclusions and Clinical Relevance —Osteoma of the oral and maxillofacial regions is an uncommon tumor in cats. Most cats are examined during an advanced stage of the disease, when treatment options may be limited. Although osteoma is a benign tumor, the recommendation is to perform a clinical evaluation, diagnostic imaging, biopsy, and treatment early in the disease process, when less invasive surgical approaches may be feasible.
To determine the effect of unilateral condylectomy on dental occlusion in cats.
Twelve feline cadaver heads were randomly submitted to either a right or left unilateral condylectomy of the temporo-mandibular joint. The distance between the mandibular and maxillary canine tooth was measured before (B0) and after the unilateral condylectomy (P0). A right or left latero--lateral standardised force (4 N) was applied to the mandibular mentus area before and after the surgical procedure. These measurements were analysed with a linear model for repeated measures.
The comparative analysis between pre- and postsurgical values indicated no significant variation in teeth displacement following condylectomy between B0 and P0 measurements. Statistically significant differences were detected after either left or right condylectomy with respect to all measurements after application of the standardised forces. Occlusion changes are significant when comparing bites before and after surgery.
Unilateral condylectomy causes a significant increase in latero-lateral amplitude of jaw movement which might clinically affect feline dental occlusion. Clinical studies are required to determine the effect of unilateral condylectomies on mastication and dental occlusion in feline patients.
The aim of this study was to describe the use of cone beam computed tomography as an auxiliary method to diagnose changes to the temporomandibular joints in cats. We used five cats of various ages, breeds and genders that showed clinical signs consistent with changes in the temporomandibular joint. Cone beam computed tomography enables a complete and thorough examination of the temporomandibular joints by allowing the evaluation of selected images as a whole. It also enables the identification of all anatomical structures and any changes that may be present. The results showed that this method is effective in confirming or ruling out changes in the temporomandibular joint in cats, such as disjunctions of the palatine raphe; fractures of the mandibular symphisis, zygomatic bone and condylar; and dental resorption.
Evaluation of the canine temporomandibular joint (TMJ) is important in the clinical diagnosis of animals presenting with dysphagia, malocclusion and jaw pain. In humans, magnetic resonance imaging (MRI) is the modality of choice for evaluation of the TMJ. The objectives of this study were to establish a technical protocol for performing MRI of the canine TMJ and describe the MRI anatomy and appearance of the normal canine TMJ. Ten dogs (one fresh cadaver and nine healthy live dogs) were imaged. MRIs were compared with cadaveric tissue sections. T1-weighted (T1-W) transverse closed-mouth, T1-W sagittal closed-mouth, T1-W sagittal open-mouth, and T2-W sagittal open-mouth sequences were obtained. The condylar process of the mandible and the mandibular fossa of the temporal bone were hyperintense to muscle and isointense to hypointense to fat on T1-W images, mildly hyperintense to muscle on T2-W images, and were frequently heterogeneous. The articular disc was visible in 14/20 (70%) TMJs on T1-W images and 13/20 (65%) TMJs on T2-W images. The articular disc was isointense to hyperintense to muscle on T1-W images and varied from hypointense to hyperintense to muscle on T2-W images. The lateral collateral ligament was not identified in any joint. MRI allows evaluation of the osseous and certain soft tissue structures of the TMJ in dogs.
Fractures of the caudal portion of the mandible and temporomandibular joint (TMJ) fracture-luxation can be challenging to treat with direct fixation methods. This paper describes a simple technique for the indirect treatment of caudal mandibular fracture and TMJ fracture-luxation using a subcutaneous loop of nylon leader line tunnelled around the maxilla, incisive and nasal bones, and under the mandible, placed just caudal to the canine teeth, and crimped ventral to the mandibular skin: a bignathic encircling and retaining device (BEARD). A BEARD was used to treat two immature dogs with simple, unilateral caudal mandibular fractures, six cats with unilateral injury (two with TMJ luxation, three with TMJ fracture-luxation, one with caudal mandibular fracture), and two cats with bilateral injury (comminuted caudal mandibular fracture with contralateral TMJ luxation; bilateral condylar neck fracture). The BEARD treatment failed short-term due to poor tolerance in one cat, and concurrent injuries and poor initial reduction in another cat. One cat was lost to long-term follow-up. Rostral dental occlusion was normal in six out of seven cases, and reported jaw function was normal in seven out of seven cases. The case with poor occlusion had imperfect initial reduction. Complications included dorsal nasal skin swelling or discharge, oesophagostomy tube dislodgement or blockage, BEARD loosening, and regurgitation. Treatment of uni- or bilateral caudal mandibular trauma using a BEARD can lead to clinical union, and normal rostral occlusion, provided that case selection is appropriate and immediate-post-surgical occlusion has been corrected.
The aim of this retrospective clinical study is to present the clinical experience of using dermis-fat interpositional grafts in the surgical management of temporomandibular joint (TMJ) ankylosis in adult patients. Eleven adult patients who presented with ankylosis of the TMJ were identified and included in the study. All patients underwent a TMJ gap arthroplasty which involved the removal of a segment of bone and fibrous tissue between the glenoid fossa and neck of the mandibular condyle. The resultant gap was filled with an autogenous dermis-fat graft procured from the patient's groin. All patients were followed up for a minimum of 2 years. Five of the 11 patients were found to have osseous ankylosis while 6 patients had fibro-osseous ankylosis. Two patients had bilateral TMJ ankylosis that were also treated with costochondral grafts which were overlaid with dermis-fat graft. The average interincisal opening was 15.6 mm on presentation which improved to an average of 35.7 mm following surgery. Patients were followed up from 2 to 6 years post-operatively (mean 41.5 months) with only 1 re-ankylosis identified out of the 13 joints treated. This study found that the use of the autogenous dermis-fat interpositional graft is an effective procedure for the prevention of re-ankylosis up to 6 years following the surgical release of TMJ ankylosis.
To the articulatio temporomandibularis of the domestic cat (Felis silvestris catus)
The mandibular joint of the cat is an incongruent cylindrical joint, which works as a hinge or screw joint. The course of motion is unilateral in the plane of the cutting edge of the molar/premolar border P4/M1 The articular disc is a connective tissue membran: its new function is decreasing the friction.
The Transverse Movement of the Temporo-mandibular Joint (Translation Movement) of the Dog, also with Reference to Dysplasia of this Joint in the Dachshund Contrary to the accepted opinion, transverse movement is possible in the temporo-mandibular joint of the dog. This movement is arched and is important for mastication. Analysis of transverse movement of the temporo-mandibular joint was done in 20 dog breeds. Accidentally dysplasia of the temporo-mandibular joint was found in the dachshund, a phenomenon which has not been described before.ZusammenfassungAm Kiefergclenk des Hundes ist entgegen bisheriger Lehrmeinung auch eine Translationsbewegung nachweisbar. Sie verlauft in einer Bogenbahn und ist für den Mastika-tionsvorgang bedeutsam. Die Analyse der Kieferseitwrts-bewegung wird bei 20 Hundcrasscn durchgefiihrt. Für den Dachshund (Teckel) ergab sich rein zufllig das bisher nicht bekannte Vorliegen einer Dysplasie des Kiefergelenks.
The radiographic anatomy of the temporomandibular joint in the dog and cat is described in dorsoventral and oblique projections. The positioning for different oblique views in conventional radiography and technical details of computed tomography are reviewed. Typical radiographic features of craniomandibular osteopathy, dysplasia, luxation, subluxation, fractures, ankylosis, degenerative joint disease, infection, and neoplasia involving the temporomandibular joint are discussed.
Two cases are described with abnormal jaw movement due to callus formation following skull fracture. Both cases were successfully treated by resection of the zygomatic arch.
A clinical study of 60 patients who underwent 66 costochondral arthroplasties during the period 1969-1984 is presented. In nearly half of the cases ankylosis was the main indication for operation, followed by dysplasia, tumours and osteomyelitis. The results showed that all cases in which the rib was decorticated to fit into the mandible as an inlay healed well. The mean time of IMF was 3.5 weeks. In the majority of the patients (67%) the postoperative function of the mandible was considered to be good or excellent, and nearly all patients were pain free. There were no postoperative chest infections and only one case of pneumothorax. Motor and sensory disturbances in the lower lip were each diagnosed in ten per cent of the patients.
Diagnostic imaging of the temporomandibular joint has undergone a revolutionary development during the last two decades. With advanced modalities we have been able to differentiate between different articular entities in patients with temporomandibular joint disorders. The purpose of this article is to review and discuss these modalities and their contribution to our present knowledge, with emphasis made on current trends in diagnostic temporomandibular joint imaging. The main section deals with diagnostic imaging of the subgroup of disorders with internal derangement caused by disk displacement including posttreatment imaging. Imaging of pathologic entities characterized by chronic inflammation such as rheumatoid arthritis are discussed in the second section. Finally, the potential of diagnostic imaging of infrequent conditions such as tumors is briefly reviewed. Magnetic resonance imaging has surpassed arthrography and computed tomography for the evaluation of most patients in these three subgroups. In patients who have various forms of disk displacements with or without accompanying bone abnormalities, a diagnostic accuracy of at least 90% may be achieved by oblique sagittal and coronal magnetic resonance imaging. In addition, alterations in the condylar marrow may be detected. T2-weighted magnetic resonance imaging can make a significant diagnostic contribution by demonstrating inflammatory reactions such as joint effusion and marrow edema. In the subgroup of patients with chronic inflammatory diseases, magnetic resonance imaging may also demonstrate abnormalities not shown with other imaging modalities. Disk deformation, fragmentation, and destruction may indirectly suggest the presence of synovial proliferation/pannus formation, which in selected cases may be directly depicted with intravenous gadopentetate dimeglumine. For more detailed evaluation of the bone condition and of soft tissue calcifications in joints with inflammatory diseases, tumors, or other disorders, computed tomography is the preferable imaging modality.
A variety of interposition materials have been used to prevent recurrence after arthroplasty in treatment of temporomandibular joint ankylosis. The purpose of this retrospective study of our experience was to compare the different materials (skin, temporal muscle, homologous cartilage) used for interposition arthroplasty over a period of 22 years. A total of 25 patients (32 joints) with at least 3 years of follow-up were included. Good results were achieved in 92% of cases using total full thickness skin graft and 83% of cases using temporal muscle flap. Homologous cartilage gave poor results.
Two cats with temporomandibular joint ankylosis were examined. Difficulty in opening the mouth and malocclusion were associated with trauma and fracture around the zygomatic arch and the condyle of the mandible after an automobile accident. Unilateral condylectomy or aggressive caudal mandibulectomy was performed to improve quality of life. Excision arthroplasty of the temporomandibular joint improved mandibular function and appearance. Some malocclusion remained but had no clinical significance.
The purpose of this study was to determine the cause of temporomandibular ankylosis and the long-term results of gap arthroplasty with coronoidectomy followed by immediate postoperative jaw exercises as a treatment of the condition.
This retrospective study evaluated the cause of temporomandibular joint ankylosis and the 36-month postoperative results of gap arthroplasty in 50 patients (62 joints). The patients were divided into 2 groups; group I (aged 0-12 years) consisted of 29 cases (24 unilateral and 5 bilateral; 34 joints); group II (aged 13-30 years) consisted of 21 cases (14 unilateral and 7 bilateral; 28 joints). A postoperative jaw opening exercise regimen was followed. Descriptive statistics, the Wilcoxon signed rank test, and rank sum 2-sample (Mann-Whitney) tests were applied.
Trauma to the temporomandibular joint was documented as a major etiologic factor in 86% of cases. The 36-month postoperative mean maximal incisal opening was 30.62 mm (+/- 6.25 mm) for group I and 30.14 mm (+/- 3.9 mm) for group II. The P value in each group was highly significant for the Wilcoxon signed rank test; the Mann-Whitney test showed no difference between the groups, indicating that both groups had done well. The recurrence rate was 2%.
Trauma is the major cause of temporomandibular joint ankylosis in India. The long-term functional results of gap arthroplasty are satisfactory and comparable to those obtained through use of other treatments. Postoperative exercises play a crucial role in lasting success.
Ankylosis of the temporomandibular joint (TMJ) in the cat is an unusual complication of traumatic lesions involving articular (true ankylosis) or periarticular structures (false ankylosis). Seven cats with true ankylosis of the TMJ (four cases unilateral and three cases bilateral), of which previous trauma had been documented in five cases, were referred to the authors' clinic between September 1991 and October 1996. Radiographic assessment was performed in all cases, using dorsoventral and oblique projections. Five subjects underwent arthroplastic excision of the TMJ and, in the remaining two cases, stretching of the jaws was performed under general anaesthesia. The surgical outcome was satisfactory in all but one case, where partially decreased joint mobility was observed (follow-up time one to five years), but in the two cases where non-surgical treatment was carried out, recurrence of TMJ ankylosis was observed (follow-up time two to five months). In the authors' experience, surgery represents the treatment of choice for TMJ ankylosis in cats. Additional mandibular symphysiotomy can confirm the radiological findings in unilateral cases.
Temporomandibular joint (TMJ) ankylosis results from trauma, infection and inadequate surgical treatment of the condylary area. Many techniques for treatment have been described so far. However, none of them gave uniformly successful results. A limited range of intrinsical opening due to relapse, loss of vertical height of the affected ramus, foreign body reactions and reankylosis are expected complications. However, wide bone resection, the use of interpositional spacer, insensitive and aggressive physiotherapy immediately after the operation are the basic principles as agreed by many authors. In this article, a review of the historical background of the treatment has been discussed.
A clinical and retrospective evaluation of 42 patients treated for this disorder showed that 89% of all patients had unilaterally and 11% had bilateral ankylosis. From the viewpoint of the techniques we used, patients fell into three groups. In two groups, two different type of spacers were used, and in the third group gap arthroplasty were performed for the treatment of TMJ ankylosis.
Our results revealed a predominance of traumatic aetiology. The highest incidence was between the ages of 11 and 20. A total of 45.24% of the patients were treated by interpositional arthroplasty by using acrylic spacer, 11.90% of the patients by sylastic sheet used as an interpositional material and the rest of the cases (42.86%) were treated only by gap arthroplasty.
The advantages of the spherical acrylic spacer and gap arthroplasty were discussed. The advantages of the techniques are, shorter operating time, and more importantly its very low cost.
The spectrum of disease that affects the temporomandibular joint (TMJ) can be varied. To differentiate among the diseases that cause pain and dysfunction, an intimate knowledge of the anatomy, physiology, and pathology of this region is necessary. Due to the joint's complex anatomy and relationship to the skin, it has been difficult to image in the past. Magnetic resonance imaging is ideally suited for visualizing TMJ because of its superb contrast resolution when imaging soft tissues. Magnetic resonance imaging allows simultaneous bilateral visualization of both joints. The ability to noninvasively resolve anatomic detail can be performed easily and quickly using magnetic resonance imaging. The development of magnetic resonance imaging has greatly aided the diagnosis of TMJ disorders. An understanding of TMJ anatomy and pathogenesis of TMJ pain is crucial for interpretation of magnetic resonance imaging and subsequent treatment.
The pathomechanics of osteoarthritis in the human temporomandibular joint (TMJ) are unknown. Compromised lubrication is a potential factor, but, lubrication within even the normal TMJ is not understood completely. Weeping lubrication is a concept that may be applicable to the TMJ. A characteristic of weeping lubrication is a slow increase in friction during static loading. The rate of increase in friction is related to the rate of lateral movement of synovial fluid away from the loading area. The TMJ disc is expected to be the main source of TMJ lubrication. This study tested two variables, disc thickness and magnitude of trauma to the disc, as factors that can affect the rate of flow of synovial fluid and thus alter lubrication of the disc surfaces. To test these variables, TMJ disc surface friction was measured before and after an impulse load. Before the impulse load, all discs demonstrated a gradual increase in friction during light static loading. The rate of increase in friction was inversely related to the disc thickness (R(2)=0.75). After an impulse load of known magnitude and peak force, disc surface friction was higher. The magnitude of this surface friction was correlated with the magnitude of the impulsive blow (R(2)=0.89) and the area of surface damage (R(2)=0.85). Disc thickness was a significant factor in determining the minimal impulse needed to produce higher surface friction (R(2)=0.99). These results confirm that disc thickness and trauma to the disc affect surface friction in the TMJ, and therefore may be important factors in compromised lubrication and the development of osteoarthritis.
Limitation of mouth opening can be caused by bony or fibrous ankylosis of the temporomandibular joint as sequela to trauma, infection, autoimmune disease, or failed surgery. Various procedures have been reported for treatment of temporomandibular joint (TMJ) ankylosis; this article aims to describe the diagnostic protocol and the surgical procedures adopted at the department of Maxillo-Facial Surgery of Rome University "La Sapienza". Between 1980 and 2000, 123 patients affected by TMJ ankylosis came under our observation; 60 of them (25 females and 35 males of 30 years average age) underwent surgery; bilateral TMJ ankylosis was observed in 21 cases, right-sided in 20 cases, left-sided in 19 cases. In 12 cases coronoid processes were involved. Etiopathogenesis was traumatic in 48 cases, septic in 5 cases, auto-immune (RA and seronegative spondyloarthropathies) in 5 cases; after block removing, arthroplasty was performed with pedunculated flap of temporal muscle (10 cases), Silastic material (11 cases), or lyophilized dura mater (2 cases). Simple condylar shaving was used in the remaining 36 cases. All patients under treatment showed a distinctive improvement both in articular functionality and symptoms; secondary surgery was necessary in seven cases due to the onset of articular complications from previous surgery. Silastic removal was necessary in five cases due to its inducement of foreign body granuloma. Follow-up was performed at 12, 24, and 48 months and 5 years postoperatively. In our opinion the gold standard surgery of TMJ ankylosis today is represented by shaving of articular surfaces and subsequent arthroplasty with or without temporal muscle myofascial flap interposition, whereas the use of Silastic as alloplastic material could be associated to an increased persistence of the local symptoms and a higher risk of foreign body granuloma and it may favor ankylosis relapse and hinder rehabilitation.
Direct or indirect trauma to the temporomandibular joint (TMJ) may cause several injuries such as fibrous adhesion, ankylosis and fracture. The aim of this study was to examine and compare the histological changes of TMJ and adjacent soft tissue after direct or indirect trauma to TMJ. In this study, a total of 35 healthy young adult guinea pigs were exposed to direct and indirect trauma to their TMJ, and histologic evaluation was done after 24 h, 7, 15 and 45 days. Hemorrhage was the most frequent complication, following that enlargement of the disc, adhesion of the disc to the condyle and fracture of the condyle were seen in both groups. There were regenerative changes in adjacent muscles of the TMJ in indirect trauma group when compared to direct trauma group. Regenerative changes were more obvious on days 15 and 45. As a result, it may be suggested that when a trauma comes to the maxillo-mandibular complex, even TMJ is indirectly affected, TMJ and its adjacent soft tissues should also be examined clinically and followed closely.
The authors present a review of 14 patients with temporomandibular joint ankylosis treated between March 1992 and February 1997. Etiology of the ankylosis was trauma in four patients, ear infection in two, systemic infection in one case, congenital in another, and unknown in six. Patients were divided into two groups, according to their age: 16 years and under and over 16 years of age. The basic principle of surgical treatment in both groups is ample access for osseous resection and coronoidectomy. Costochondral grafts were used in group one (nine patients), while interposition of a silicone block, was performed in the second group (five patients). Follow-up evaluations were from twelve to 53 months (average 28.2 months). One case of recurrence occurred in the first group and no recurrences in the second group. The average long-term mouth opening in both groups was 32.8 mm.
Restoration of normal function and jaw movement in patients with temporomandibular joint (TMJ) ankylosis is difficult. Various techniques have been defined for the treatment of the condition.
This study is based on the pre-, intra- and post-operative evaluation of 78 TMJ operations in 59 patients who were treated for TMJ ankylosis between 1985 and 2002.
The patients in this study were evaluated with regard to age, gender, aetiology of ankylosis, ankylosis type/classification, existing facial asymmetry, maximal pre- and post-operative mouth opening, the arthroplasty methods (gap and interpositional arthroplasty) including complications and recurrence of ankylosis.
Falls represented the most widespread aetiological factor (85%), and women constituted the group with the highest incidence of ankylosis (61%). Forty cases were unilateral (68%) and 19 bilateral (32%); 82% (64 joints) were of the bony type. Gap arthroplasty was applied in 34 of the 59 cases (58%) and interpositional arthroplasty in the remaining 25 (42%). Pre- and post-operative mean mouth opening were 3.5+/-1.7 and 30.7+/-3.0mm, respectively. Re-ankylosis was noted in 5%.
In addition to radical and sufficient resection of the ankylosed bone, early post-operative exercises, appropriate physiotherapy and close follow-up of the patient play an important role in the prevention of post-operative adhesions and re-ankylosis.