Presentation A five-year-old spayed female German shepherd, Luna, was presented to an emergency facility after biting the moving blade of a zero-turn lawn mower. She was previously healthy with no pre-existing medical conditions or co-morbidities. The dog is historically outside while the owner mows the grass. The grass was longer than usual, so the guard on the lawnmower blade was raised approximately eight inches off the ground, exposing the blades of the mower. The owner reported that he suspects Luna saw a rodent disturbed by the lawnmower at some point and attempted to chase it, resulting in the dog biting the moving blades of the lawnmower. The dog purportedly did not verbalize following the trauma and could immediately ambulate. The dog remained conscious throughout the post-trauma period. Luna was presented to an emergency/specialty hospital following a referral from her primary care veterinarian. The primary care veterinarian had treated the dog with two doses of butorphanol (0.2 mg/kg IV at presentation and repeated one hour later before transfer) before referral. No diagnostics were performed by the primary care veterinarian. On presentation at the emergency facility, Luna was bright, alert, responsive, and breathing well (Figure 1). Her mucus membranes were pink and moist, with a capillary refill time of less than two seconds. Her lungs auscultated clear, and cardiac auscultation was normal. Figure 1. Photo courtesy Dr. Rachael Currao Severe facial trauma was reported, with the majority of the trauma involving the rostral right maxillary and mandibular regions. An obvious fracture to the mandibular symphysis was identified, along with a suspected right rostral maxillary fracture. The hard palate was noted to be fractured on awake intraoral exam near teeth 104-106, with visible extension into the nasal cavity. The tongue appeared to have normal movement and did not appear damaged. A moderate amount of sanguinous discharge was noted from the oral cavity. The eyes, ears, and cervical region appeared unaffected by the trauma. No other overt orthopedic or neurological abnormalities were noted. The dog was stabilized with intravenous crystalloids (Lactated Ringer’s solution, 90 ml/kg/day), opioids (methadone, 0.3 mg/kg IV q6 hours), non-steroidal anti-inflammatory medication ([NSAID] carprofen, 4.4 mg/kg SQ q24 hours), anti-nausea medication (maropitant, 1 mg/kg IV q24 hours), and antibiotics (ampicillin/sulbactam, 30 mg/kg IV q8 hours). An Elizabethan collar was placed to prevent self-trauma. A complete blood count and a serum chemistry profile were unremarkable aside from mild hyperglycemia and mild neutrophilic leukocytosis. The hematocrit was 48 percent, with a total protein of 5.8 g/dL. The decision was made not to perform any radiographs or sedated procedures over the weekend, pending surgery consultation and CT scan the following week. No tape muzzle or any other external coaptation device was placed. The dog maintained NPO prior to imaging diagnostics and surgery. Diagnostics and findings The day following the presentation, the patient’s hematocrit decreased to 20 percent, with a total protein of 4.6 g/dL, although the oral bleeding had decreased considerably by this time. After a discussion with the owner on the pros and cons of a transfusion, the owner elected to proceed with a packed red blood cell transfusion (DEA 1.1 negative, approximately 10 ml/kg total volume administered over four hours). The morning following the transfusion, the packed cell volume was 26 percent, with 5.2 g/dL total solids. No further blood transfusions were administered. Two days following the initial injury, a CT scan (Figures 2-4) with intravenous contrast was performed to evaluate the extent of damage. While under anesthesia, the intraoral wounds were assessed. The initial surgical plan before CT scan was to perform open reduction and internal fixation (ORIF) of the fractured portion of the maxilla and mandible using stainless steel metal plates and screws. Figure 2. Photo courtesy Dr. Rachael Currao A CT scan with three-dimensional reconstruction revealed multiple acute, traumatic, unstable, open facial fractures involving the right maxilla, nasal bone, incisive bone, and mandible. The right rostral maxillary bone was absent, including the right maxillary canine, right incisors 1-3, and left first and second maxillary incisor teeth. Figure 3. Photo courtesy Dr. Rachael Currao There was a large defect of the right rostral maxillary with exposure of the nasal cavity extending into the oral cavity. The right-sided mandibular incisive bone fractures were open and severely comminuted, extending from the mandibular symphysis to the third mandibular premolar tooth with separate fracture fragments, including the right mandibular canine, as well as first and second premolar teeth. Figure 4. Photo courtesy Dr. Rachael Currao The right mandibular canine tooth was fractured with a retained portion of tooth root within the remaining intact portion of the right mandible. There was also a fracture of the mesial aspect of the alveolar bone of the left mandible exposing the tooth root of the left mandibular canine tooth. The frontal sinuses were unremarkable and there was no evidence of fractures extending into the cranial vault. The missing bone of the maxilla was not recovered from the site of injury and was not identified in the dog’s digestive tract on abdominal radiographs. Due to the missing portion of the maxillary bone, ORIF fixation of the fractured maxilla was no longer a possible treatment option. We discussed referring the patient to a facility with 3D computer printing and prosthetic capabilities versus soft tissue reconstruction alone at our facility. After discussing treatment options with the owner, reconstructive surgery at our facility was elected. Surgery During surgery, the smaller fractured portions of the maxilla were excised. The devitalized tissue of the intraoral cavity was resected, and the remaining portions of the wound were debrided to bleeding tissue. Suture reconstruction of the soft tissues of the nasal cavity and hard palate region was performed to provide a separation between the oral and nasal cavities. The surgical procedure was similar to closure following a rostral-lateral maxillectomy procedure. A two-layer closure was performed using 2-0 monofilament poliglecaprone 25 with triclosan in an interrupted intradermal pattern followed by a simple interrupted pattern to oppose the oral mucosa. Very minimal tension was present at the incision line. The wounds on the external rostral nasal region were debrided and closed using 2-0 monofilament poliglecaprone 25 with triclosan in an interrupted intradermal pattern. The skin edges were opposed in this region using a monofilament polypropylene suture is a simple interrupted appositional pattern. Very minimal tension was present at the incision site in this region. The fractured portion of the mandible was comminuted, and the right mandibular canine tooth was fractured. Due to the extent of the trauma, the decision was made to excise the fractured portion of the mandible and reconstruct the soft tissue of the remaining defect. The retained portion of tooth root from the fractured right mandibular canine tooth was extracted from the remaining intact portion of the right mandible. The medial aspect of the left mandibular canine tooth was exposed due to bone loss in the mandible. The decision was made not to extract this left mandibular canine tooth at the time of surgery. Post-op and recovery Luna ate hand-fed soft canned dog food and drank water well out of a bowl the day following surgery (Figure 5). The patient weaned off intravenous fluids and transitioned to oral medications the day following surgery. The dog’s hematocrit was maintained at 26 percent one day post-operatively. Figure 5. Photo courtesy Dr. Rachael Currao Luna was discharged from the hospital two days following surgery with instructions for the owner to hand-feed soft canned food rolled into one-inch spheres for two weeks. The patient was prescribed oral antibiotics (amoxicillin and clavulanate potassium, 13.75 mg/kg PO q12 hours for seven days), NSAIDs (carprofen, 2.2 mg/kg PO q12 hours for seven days., and pain medication (gabapentin, 5 mg/kg PO q8 hours for seven days). An Elizabethan collar was used to prevent self-trauma at the surgery site. The owner was instructed to maintain the dog’s activity to short leash walks only. No at-home treatment was to be performed on the wounds, and the owner was instructed not to open the dog’s mouth or attempt to evaluate the intraoral incision. During the two-week post-operative recheck appointment, mild dehiscence was noted at the rostral aspect of the intraoral incision. The extraoral and nasal incisions as well as the mandibular incisions were well healed. The external polypropylene skin sutures were removed. The dog’s recheck hematocrit was increased to 40 percent and within the normal reference range. At this time, the dog was clinically doing very well, eating and comfortable, with only occasional sneezing episodes not associated with eating or drinking reported by the owner. The dog was placed under general anesthesia for revision surgery. The dehisced region of the rostral oral cavity was debrided and reopposed with a double-layer suture apposition as previously detailed. Two weeks following the revision surgery, the intraoral incision was well healed, and there was no further communication between the oral and nasal cavities. The dog was then transitioned back to dry kibble, which it could prehend, chew, and swallow well. During the last follow-up several months following surgery, the left mandibular canine tooth with the previously exposed root remained healthy and viable. The owner was very pleased with the cosmetic and functional outcomes and reported that the dog continues to live an excellent quality of life. Luna one year post-operation is "living her absolute best life, hiking, biking, swimming...," according to her owner. Photos courtesy Danielle McDermott Key takeaways Reconstruction is possible in the event of extensive maxillary bone loss. With maxillary trauma and bone loss, prosthesis is not mandatory for good clinical outcome. Excellent post-operative function and quality of life are achievable. Cosmetic outcomes, although altered, can be very good and acceptable to owners. Rachael Leigh Currao, DVM, DACVS-SA, graduated from the Cummings School of Veterinary Medicine at Tufts University. In 2007, Dr. Currao began a one-year small animal rotating internship at The Animal Medical Center in New York, N.Y., where she completed a three-year small animal surgical residency and became board-certified in 2022. Her primary surgical interests are wound management, urinary tract surgery, brachycephalic airway repair, polytrauma, emergency surgeries, and fracture repair. Dr. Currao’s research and publications involve vascular thrombi, radical maxillectomies, hydraulic urethral occluders, laparoscopy vs. laparotomy biopsies, and abdominal septic effusion.
