Piezosurgical bone-cutting technology reduces risk of maxillectomy and mandibulectomy complications in dogs.

OBJECTIVE: To report the complication rate of dogs undergoing oral oncological surgery when using a bone-cutting piezoelectric unit for osteotomies. CLINICAL PRESENTATION AND PROCEDURES: Retrospective cohort evaluation of medical records from 2012 through 2022 for canine patients that underwent mandibulectomy or maxillectomy for the treatment of oral neoplasia at the Companion Animal Hospital at Cornell University. Cases were included if osteotomy was performed using a piezoelectric unit. Medical records were then reviewed for documentation of intraoperative hemorrhage and administration of blood products. RESULTS: 41 maxillectomies and 57 mandibulectomies met the inclusion criteria (98 in total). Only 1 (1.02%) case was associated with excessive surgical bleeding requiring administration of blood products. CLINICAL RELEVANCE: Results of this study show that intraoperative hemorrhage requiring the use of blood products during or immediately after a mandibulectomy or maxillectomy is rare when using a piezoelectric unit to perform osteotomies, and is substantially lower than that previously reported when using oscillating saws or other bone-cutting devices for maxillectomies.

A rare case report of extensive mandibular osteoma corrected by unilateral mandibulectomy: Cytological, radiological, and pathological investigation.

Background: Osteoma is a benign bone tumor that rarely affects animals. The most common bones involved with this tumor included the mandible, maxillofacial bones, and nasal sinuses. Definitive diagnosis is based on pathology findings which allow for differentiation with other bone lesions. Case Description: The patient, a 5-year-old intact male Mongrel dog presented with a huge mandibular mass that involved both the right and left mandible, and led to dental occlusion. The radiography was performed and depicted the intense mass with a well-demarcated edge, a short transitional zone between normal and abnormal bone, and a smooth rounded radiopaque appearance. The investigation according to the fine needle aspiration showed the presence of oval to spindle shape cells with poorly malignancy criteria, fatty cells, reactive osteoblasts, and osteoclasts based on a population of spindle-shaped cells, and low numbers of degenerated neutrophils, bacteria, and few macrophages. Then, the radiographic assessments and cytology findings demonstrated the osteoma and were referred for surgical intervention. A unilateral mandibulectomy was performed, and the lesion was sent to the histopathology laboratory. The histopathology evaluation showed osteocyte proliferation without malignancy features. The osteoblast cells also showed no atypical proliferation that endorses the osteoma tumor. Conclusion: Although mandibular and maxillofacial bone resection in small animals have different tolerations, this patient became a candidate for surgery for future better nutrition and prevention of facial deformity and dental malocclusion. Follow-up after osteoma is one of the most necessary post-operation treatments to check the regeneration of the mass. There are considerable data in this report that should regard this tumor as a possible differential diagnosis for mandibular tumors.

Quality of Life After Partial Mandibulectomy or Maxillectomy in 45 Dogs With Oral Tumors.

Treatment for oral tumors in dogs may involve aggressive surgery, radiation therapy, and/or chemotherapy. It is of utmost importance that veterinarians can document the good quality of life (QoL) for patients during and after cancer treatment. In this retrospective study, medical records from 2 private practices during a 10-year period (2011-2020) were searched to identify dogs with confirmed histopathological diagnosis of an oral tumor. Owners of dogs who underwent surgery received a questionnaire to assess their perception of QoL before and after surgery, clinical signs from the oral tumor, pain before and after surgery, physical appearance, and drinking and eating ability after surgery. Forty-two of 45 (93%) owners answered the questionnaire. Thirty-eight owners (90%) perceived that their dog had not changed its appearance after surgery after the hair had regrown. Thirty owners (71%) reported that their dog prehended food and water normally within 4 weeks after surgery. Forty owners (95%) perceived that their dog had more "good'' than ''bad'' days after surgery. Thirty-eight owners (90%) would choose the same treatment again. Our results strongly support that dog owners perceived that their dogs had good QoL after partial mandibulectomy or maxillectomy.

Analysis of risk factors associated with complications following mandibulectomy and maxillectomy in dogs.

OBJECTIVE: To provide information about complication rates and the risk factors for complications with mandibulectomy and maxillectomy procedures in dogs. ANIMALS: 459 client-owned dogs that underwent a mandibulectomy or maxillectomy between January 1, 2007, and January 1, 2018. PROCEDURES: Inclusion criteria included a complete medical record that contained an anesthesia record, surgical report, available histopathology results, and results of CBC and serum biochemical analysis before surgery. A minimum follow-up of 90 days after surgery was required. RESULTS: 271 complications occurred in 171 of 459 (37.3%) dogs. Eighteen complications were not given a severity description. Of the remaining 253 complications, most were considered minor (157/253 [62.1%]). Multivariable logistic regression analysis revealed that only increased surgical time had a significant (OR, 1.36; 95% CI, 1.12 to 1.54) association with the occurrence of ≥ 1 complication. For each additional hour of surgery, the odds of complications increased by 36%. Preoperative radiation therapy or chemotherapy increased the odds of incisional dehiscence or oral fistula formation (OR, 3.0; 95% CI, 1.3 to 7.2). Additionally, undergoing maxillectomy, compared with mandibulectomy, increased the odds of incisional dehiscence or oral fistula formation (OR, 1.8; 95% CI, 1.1 to 3.1). Two hundred forty-four of 271 (90.0%) complications occurred in the perioperative period (0 to 3 months after surgery). CONCLUSIONS AND CLINICAL RELEVANCE: Compared with mandibulectomy, performing maxillectomy increased the risk for incisional dehiscence or oral fistula formation. Mandibulectomy and maxillectomy had a moderate risk for a complication.

Comparison of unilateral rostral, middle and caudal segmental mandibulectomies as an alternative treatment for unilateral temporomandibular joint ankylosis in cats: an ex vivo study.

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.

Bilateral rostral mandibulectomy for treatment of necrotic mandibular open fractures in two Japanese Black cattle.

Two-month-old (Case 1) and one-year-old (Case 2) Japanese Black cattle presented with bilateral rostral mandibular open fractures. At presentation, the proximal edges of each fracture were discolored and had a severe stench, indicating necrosis caused by infection. In both cases, a bilateral rostral mandibulectomy over the symphysis was performed. Although the tongues of both animals prolapsed post-surgery, they had no significant problems with eating or drinking. Case 1 showed excellent growth during fattening, and Case 2 successfully became pregnant and gave birth. Rostral mandibulectomy can be an effective surgical option for the treatment of cattle with difficulty in internal or external fixation due to unfavorable necrotic cranial mandibular open fractures.

Outcomes of eight cats with oral neoplasia treated with radical mandibulectomy.

OBJECTIVE: To report outcomes after radical mandibulectomy in cats. STUDY DESIGN: Multi-institutional retrospective study. ANIMALS: Eight cats were included. METHODS: Medical records were searched for cats with confirmed oral neoplasia treated with radical mandibulectomy. Data collected included demographics, surgical procedure, histopathological diagnosis, postoperative management, and outcomes. RESULTS: Ages ranged from 8 to 17 years. All cats had 75% to 90% of the mandible removed and feeding tubes placed. Seven cats had squamous cell carcinoma, and one cat had a giant cell tumor. Six cats ate on their own postoperatively. Three cats had local recurrence and tumor-related died at 136 and 291 days. Six cats had no recurrence, with survival times of 156, 465, 608, and 1023 days, and two cats were still alive at 316 and 461 days after surgery. The three long-term survivors died of causes unrelated to oral neoplasia. One cat died at 156 days due to aspiration of food material. The overall estimated mean survival time was 712 days. CONCLUSION: After radical mandibulectomy, independent food intake was achieved in 6 of eight cats, and four cats lived longer than one year. CLINICAL SIGNIFICANCE: Radical mandibulectomy should be considered for the treatment of extensive oral neoplasia in cats. Successful long-term outcomes are possible with aggressive supportive care perioperatively.

Segmental mandibulectomy as a novel adjunct management strategy for the treatment of an advanced cholesteatoma in a dog.

A 6-year-old spayed female Labrador retriever dog was evaluated for trismus and peripheral vestibular syndrome. Computed tomography (CT) revealed a mass arising from the tympanic bulla consistent with a cholesteatoma. A total ear canal ablation, bulla osteotomy, and adjunct segmental mandibulectomy were performed. Re-evaluation 2 weeks after surgery revealed no neurologic abnormalities, normal jaw range of motion, and no discomfort. Despite concern for recurrence of cholesteatoma based on CT imaging performed 33 months after surgery, repeat surgical intervention was not pursued as the owner considered the dog's comfort level to be satisfactory. The patient continued to do well for the 42-month follow-up period.

Mandibulectomie segmentaire comme nouvelle stratégie de gestion complémentaire pour le traitement d'un cholestéatome avancé chez un chien. Une femelle Labrador retriever de 6 ans stérilisée a été évaluée pour du trismus et un syndrome vestibulaire périphérique. La tomodensitométrie a révélé une masse issue de la bulle tympanique, compatible avec un cholestéatome. Une ablation totale du conduit auditif, une ostéotomie de la bulle et une mandibulectomie segmentaire complémentaire ont été réalisées. La réévaluation deux semaines après l'opération n'a révélé aucune anomalie neurologique, une amplitude de mouvement normale de la mâchoire et aucun inconfort. Malgré l'inquiétude suscitée par la récurrence du cholestéatome sur la base d'une tomodensitométrie réalisée 33 mois après la chirurgie, aucune nouvelle intervention chirurgicale n'a été envisagée, le propriétaire ayant estimé que le niveau de confort du chien était satisfaisant. La patiente a continué à bien se porter pendant la période de suivi de 42 mois.(Traduit par les auteurs).

Diagnosis and Treatment of an Odontogenic Epithelial Tumor in a Dog With Features of Squamous Odontogenic Tumor.

A 9-year-old standard poodle presented for a comprehensive oral health assessment and treatment, at which time a left rostral mandibular swelling was recognized. The mass was biopsied and eventually excised by a left rostral mandibulectomy en bloc resection. Histopathology supported the diagnosis of a benign, intraosseous, epithelial tumor that was otherwise unclassified. The clinical, radiological, and histological features of this case are similar to those reported for squamous odontogenic tumor (SOT) in humans. This case study relays the diagnosis, treatment, and follow-up of the first SOT-like tumor in a dog.

Kinematic analysis of mandibular motion before and after mandibulectomy and mandibular reconstruction in dogs.

OBJECTIVE: To evaluate and quantify the kinematic behavior of canine mandibles before and after bilateral rostral or unilateral segmental mandibulectomy as well as after mandibular reconstruction with a locking reconstruction plate in ex vivo conditions. SAMPLE: Head specimens from cadavers of 16 dogs (range in body weight, 30 to 35 kg). PROCEDURE: Specimens were assigned to undergo unilateral segmental (n = 8) or bilateral rostral (8) mandibulectomy and then mandibular reconstruction by internal fixation with locking plates. Kinematic markers were attached to each specimen in a custom-built load frame. Markers were tracked in 3-D space during standardized loading conditions, and mandibular motions were quantified. Differences in mandibular range of motion among 3 experimental conditions (before mandibulectomy [ie, with mandibles intact], after mandibulectomy, and after reconstruction) were assessed by means of repeated-measures ANOVA. RESULTS: Both unilateral segmental and bilateral rostral mandibulectomy resulted in significantly greater mandibular motion and instability, compared with results for intact mandibles. No significant differences in motion were detected between mandibles reconstructed after unilateral segmental mandibulectomy and intact mandibles. Similarly, the motion of mandibles reconstructed after rostral mandibulectomy was no different from that of intact mandibles, except in the lateral direction. CONCLUSIONS AND CLINICAL RELEVANCE: Mandibular kinematics in head specimens from canine cadavers were significantly altered after unilateral segmental and bilateral rostral mandibulectomy. These alterations were corrected after mandibular reconstruction with locking reconstruction plates. Findings reinforced the clinical observations of the beneficial effect of reconstruction on mandibular function and the need for reconstructive surgery after mandibulectomy in dogs.

Influence of plate type and placement on the immobilization of bilateral equine mandibular osteotomies: Ex vivo study.

OBJECTIVE: To determine the influence of plate fixation (locking or dynamic compression) and the site of application (ventral [V] or ventrolateral [VL]) on the resistance to bending of transverse mandibular fractures. STUDY DESIGN: Ex vivo, simple randomized study. SAMPLE POPULATION: Mandibles harvested from adult equine cadavers (n = 18). METHODS: Bilateral osteotomies were created 1 cm caudal to the mental foramen and perpendicular to the long axis of each mandible. Mandibles were fixed with 1 of 3 methods: (1) VL dynamic compression plate (DCP), (2) V-DCP, or (3) VL locking compression plating (LCP). Constructs were mounted on a custom testing jig and tested for resistance in bending by applying force to the rostral aspect of the mandible. Stiffness and change of distance of the dorsal osteotomy at 200 N were compared among constructs. RESULTS: VL-LCP constructs were 5.25 and 2.42 times stiffer than V and VL constructs, respectively (P<.001). Change in the width of the osteotomy gap at 200 N of load was reduced 6.04 times when osteotomies were stabilized with VL compared to V (P<.001); no difference was detected between the VL and VL-LCP constructs (P=.836). CONCLUSION: Ventrolateral LCP fixation of equine transverse mandibular osteotomies provided greater resistance to bending compared with V and VL constructs. CLINICAL SIGNIFICANCE: These results provide evidence to recommend fixation of transverse interdental mandibular fractures with VL-LCP rather than with DCP in horses.

Ventral mandibulectomy for removal of oral tumours in the dog: Surgical technique and results in 19 cases.

The purpose of this retrospective study is to describe in detail a novel ventral approach for mandibulectomy and the results in 19 dogs. The medical records of 19 dogs that received a partial or total unilateral mandibulectomy with the new ventral approach were reviewed. Information obtained included signalment, tumour type, extent of mandibulectomy, removal of regional lymph nodes, intrasurgical complications, immediate postoperative complications, histopathological diagnosis and study of margins. Intrasurgical complication occurred in one dog (haemorrhage) and required a blood transfusion. Postoperative morbidity was minor and included transient ventral cervical swelling and self-limiting sublingual swelling (two dogs). All 19 animals were discharged between 24 and 48 hours of the procedure, and appetite was considered normal at discharge. Some perceived advantages of this procedure include easy identification of all the important anatomic structures in the area, including the inferior alveolar artery and temporo-mandibular joint, and the fact that osteotomy of the zygomatic arch is not necessary (in case of caudal mandibulectomy). In addition, dissection of both mandibular and retropharyngeal lymph nodes is easily achieved by caudal extension of the same skin incision.

Management of an extensive equine juvenile ossifying fibroma by rostral mandibulectomy and reconstruction of the mandibular symphysis using String of Pearls plates with cortical and cancellous bone autografts.

OBJECTIVE: To describe a surgical technique for rostral mandibulectomy and reconstruction of the mandibular symphysis. STUDY DESIGN: Case report. ANIMAL: One 5-month-old warmblood cross filly. METHODS: A preoperative diagnosis of a juvenile ossifying fibroma was made on the basis of clinical appearance and was later confirmed via histology. The tumor was large, rapidly growing and extending to the caudal aspect of the mandibular symphysis. Computed tomography was performed for surgical planning. The tumor was excised by performing a mandibulectomy caudal to the symphysis. The mandibular symphysis was reconstructed with String of Pearls (SOP) plates. Cortex screws placed in lag fashion, a cortical bone graft from one of the mandibles and a cancellous graft harvested from the tuber coxae. RESULTS: At 9 months of age there was no sign of tumor reoccurrence, the implants were removed because of infection and the mandible had formed a new stable symphysis. The horse was able to prehend food and masticate normally. The owner was pleased with the cosmetic and functional outcome. CONCLUSION: The described surgical technique is a viable option for mandibulectomy and reconstruction of the mandibular symphysis. The technique provided adequate stability for healing to occur in the face of infection. CLINICAL SIGNIFICANCE: Neoplasia and other conditions affecting the entire mandibular symphysis can be treated by complete surgical excision and reconstruction.

Unilateral rostral mandibulectomy for gingival vascular hamartoma in two calves.

A 2-month-old female Holstein calf and a 5-month-old female Japanese black calf presented with gingival vascular hamartoma located in the interdental space between the second and third mandibular incisors in the right and left mandibles, respectively. On radiographic or computed tomographic images, osteolytic changes appeared within the mandibular bones adjacent to the masses. The masses were removed along with affected mandibular bone by using unilateral rostral mandibulectomy. After surgery, both cases exhibited a normal appetite and grew normally, with no cosmetic changes or recurrences. Unilateral rostral mandibulectomy can be applied for invasive gingival vascular hamartomas associated with osteolytic changes.

Commissurotomy.

This step-by-step feature provides a pictorial description of the commissurotomy procedure. Commissurotomy can be performed to increase surgical access to the caudal oral cavity for procedures such as total mandibulectomy, caudal mandibulectomy, and surgical access to the mandibular ramus.

Commissurorraphy in the Dog.

Commissurorraphy is a surgical procedure designed to move the lip commissure rostrally. This procedure may be helpful as a unilateral procedure in cases of unilateral mandibulectomy to support tongue function and improve esthetics. Bilateral commissurorraphy is utilized in cases of radical bilateral mandibulectomy and as a salvage procedure for support of bilateral mandibular fractures in cases where rigid surgical fixation is not feasible. Dehiscence is the most likely complication of commissurorraphy. Tension can be reduced at the rostral extent of the incision by utilizing mattress sutures, intravenous fluid tubing, and/or buttons to prevent tearing through sutures.

Segmental Mandibulectomy in the Dog.

This step-by-step manuscript describes surgical technique of segmental mandibulectomy in the dog. This surgical procedure may be indicated for the excision of small- to mid-sized neoplasms or as a salvage procedure for mandibular fractures. Long-term postoperative complications are not common and cosmetic appearance following the procedure is generally acceptable to the pet owner.

Mandibulectomy for treatment of fractures associated with severe periodontal disease.

Six cases of mandibular fractures associated with severe periodontal disease that had been treated by mandibulectomy, due to intense bone loss, were evaluated retrospectively. The dogs were mainly older, small breed dogs that had suffered a traumatic event. Four dogs had a bilateral mandibulectomy and 2 a unilateral mandibulectomy.

Mandibulectomie pour le traitement de fractures associées à une maladie parodontale grave. Six cas de fractures mandibulaires associées à une maladie parodontale grave qui avaient été traités à l'aide d'une mandibulectomie, en raison d'une perte osseuse intense, ont été évalués rétrospectivement. Les chiens étaient pour la plupart âgés et de petite race et ils avaient été victimes d'un traumatisme. Quatre chiens avaient subi une madibulectomie bilatérale et 2 une mandibulectomie unilatérale.(Traduit par Isabelle Vallières).

Regenerating Mandibular Bone Using rhBMP-2: Part 1-Immediate Reconstruction of Segmental Mandibulectomies.

OBJECTIVE: To describe a surgical technique using a regenerative approach and internal fixation for immediate reconstruction of critical size bone defects after segmental mandibulectomy in dogs. STUDY DESIGN: Prospective case series. ANIMALS: Dogs (n = 4) that had reconstruction after segmental mandibulectomy for treatment of malignant or benign tumors. METHODS: Using a combination of extraoral and intraoral approaches, a locking titanium plate was contoured to match the native mandible. After segmental mandibulectomy, the plate was secured and a compression resistant matrix (CRM) infused with rhBMP-2, implanted in the defect. The implant was then covered with a soft tissue envelope followed by intraoral and extraoral closure. RESULTS: All dogs that had mandibular reconstruction healed with intact gingival covering over the mandibular defect and had immediate return to normal function and occlusion. Mineralized tissue formation was observed clinically within 2 weeks and solid cortical bone formation within 3 months. CT findings at 3 months showed that the newly regenerated mandibular bone had ∼50% of the bone density and porosity compared to the contralateral side. No significant complications occurred. CONCLUSION: Mandibular reconstruction using internal fixation and CRM infused with rhBMP-2 is an excellent solution for immediate reconstruction of segmental mandibulectomy defects in dogs.