Dogs who develop a disease or injury to the upper jaw may require a veterinary surgical procedure called a partial maxillectomy. This surgery involves removing bone and tissue in the upper jaw. There are different types of partial maxillectomy based on which part of the jaw is affected. Read on to learn about the reasons for performing a partial maxillectomy, potential complications from surgery, feeding recommendations, and post-surgery quality of life.
What Is a Partial Maxillectomy?
Let’s start with a dog’s oral anatomy. Like humans, dogs have a set of structures and organs involved in chewing and moistening food before it’s swallowed. Among these structures are the upper and lower jaws, which are called the maxilla and mandible, respectively. The mandible is made up of two bones and holds the lower teeth in place.
“The maxilla are the two bones fused that form the upper part of the upper jaw, the roof of the mouth, and parts of the eye socket and nose,” says Dr. Jerry Klein, DVM, Chief Veterinarian for the American Kennel Club. “The maxilla is a major bone in the face that holds the top teeth in place and supports muscles involved in chewing and making facial expressions.” This bone separates the nasal cavity from the oral cavity.
“A maxillectomy is a surgical procedure involving the removal of all or part of the maxilla,” he says. “A mandibulectomy is the removal of part or all of the lower jaw.” These surgeries require general anesthesia and may be necessary to correct damage to the jaw or remove tumors.
Reasons for Performing a Maxillectomy or Mandibulectomy
Maxillectomies and mandibulotomies “are significant surgeries recommended to be performed by certified veterinary surgeons, often at a tertiary referral institution,” Dr. Klein says. Typically, the reason for removing part or all of the upper or lower jaw is to treat benign or malignant tumors. These tumors could be interfering with the functioning of the jaw or could spread to other parts of the body and become a life-threatening situation.
“Maxillectomies, full or partial, are performed to ensure complete removal of a tumor and to improve outcomes,” he explains. Often, these surgeries are part of a cancer treatment plan that involves adjunct radiation and chemotherapy and, in cases of melanoma, immunotherapy, he adds. The most common oral tumors in dogs are:
- Malignant melanoma (a type of skin cancer)
- Squamous cell carcinoma (a type of skin cancer)
- Fibrosarcoma (cancer that affects bone and soft tissue)
- Osteosarcoma (a type of bone cancer)
- Benign Acanthomatous ameloblastoma (a noncancerous tumor that develops in the jaw)
Diagnosing Oral Tumors
The veterinarian must first establish which type of tumor the dog has and how much it has spread to surrounding tissues. This is achieved through a histological diagnosis of cell, tissue, or organ samples by staining and examining them under a microscope. They’ll start with a physical exam, taking note of the dog’s age, breed, sex, reproductive status, coat color, and distinctive markings, known as signalment.
To aid in diagnosis, the vet will use “fine needle aspirate, which means using a needle and syringe to sample a lump, and as a gold rule, biopsy which involves taking a bit of tissue for analysis,” he says. “This is done most of the time under general anesthesia.” Next, the vet will conduct CT scans to assess the extent of the tumor invasion and metastasis (spread of cancer cells), so they can plan for surgery. At this time, they may also take fine needle aspirates of the regional lymph nodes, which are small structures beneath the skin that can become enlarged due to disease or inflammation.
The results of the CT scan will help determine the type of surgery needed. “Parts of the mandible or maxilla or the whole mandible or maxilla may need to be removed,” he says. “In some cases, partial maxillectomies are performed for treatment of severe jaw fractures or jaw fractures that do not heal, are severely infected, or have been extensively damaged from trauma.”
Types of Surgical Techniques and When They Are Necessary
“Removal of all or part of the maxilla is dictated by the location and extent of the lesion,” Dr. Klein says. There are different types of maxillectomy procedures based on which part of the upper jaw is damaged or diseased. These include:
- Unilateral rostral (nearest to the nose) maxillectomies are indicated for lesions confined to the hard palate on one side
- Bilateral rostral maxillectomies are indicated for bilateral lesions of the rostral hard palate
- Lateral maxillectomies are indicated for laterally placed mid-maxillary lesions
- Bilateral maxillectomies are indicated for bilateral palate lesions
“Surgical decisions are also dictated or limited by the affected lip or gum tissue, extension of the lesion across the midline of the rear portion of the hard palate, and whether there is sufficient tissue or skin to reconstruct any oral or nasal defect caused by the removal of the lesion,” he explains. Normally, the surgeon will schedule a consultation with the client to discuss these procedures. They will explain the reasons for the type of surgery, any complications from surgery or anesthesia, and risks to the dog during and after surgery.
Post-Surgical Complications, Tumor Recurrence, and Survival
The prognosis for canine maxillectomy depends on the type and location of the tumor, Dr. Klein says. “Surgical survival rates are generally good, with 1-year survival rates ranging from 70 – 90% following maxillectomy surgery,” he says. Post-surgical complications include:
- Pain
- Excessive facial swelling
- Bleeding from the nose
- Facial pawing
- Difficulty eating
- Trauma to the lip
- Oronasal fistula formation (an abnormal opening between the oral and nasal cavity after infection or tooth loss)
- Wound dehiscence (a surgical complication where an incision reopens)
Despite these complications, when a surgery is performed by a qualified surgeon, “good functional and cosmetic outcomes are expected and studies report high owner satisfaction with function and quality of life after maxillectomy,” Dr. Klein says. In a 2023 study of 45 dogs who underwent partial mandibulectomy or maxillectomy for oral tumors, most respondents said their dogs had more “good” than “bad” days post-surgery. Their dogs were able to eat and drink normally within four weeks of the surgery, and most owners said they would choose the same treatment again.
Local tumors can recur in approximately 40 – 50% of dogs, especially those with malignant tumors such as malignant melanoma, fibrosarcoma, and osteosarcoma. Recurrence of local tumors is more common following maxillectomy compared to mandibulectomy, he says. Outcomes are more favorable for maxillectomy in cases involving rostral tumors and benign disease when the diseased tissue has been removed, called histological resection or complete excision.
When there is incomplete histological resection, meaning there are still tumor cells at the edge of a surgical excision, dogs are 3.6 times more likely to have a tumor-related death, he says. In addition, “dogs with caudal oral maxillary tumors are 4.3 times more likely to have a tumor-related death compared to dogs with tumors rostral (in the region of the nose and mouth) to the third premolar,” he says.
Post-Operative Management Guidance
As with any type of surgery, it’s important to follow the veterinarian’s instructions to ensure optimal healing and recovery. This applies to medication, diet, and activity restrictions during the postoperative phase. For instance, the vet may prescribe medication to help reduce pain and swelling. They may also recommend ice packs or using an E-collar to prevent your dog from pawing or scratching the surgical site, Dr. Klein says.
Since this is a major surgery, his advice is to restrict the dog’s activity for the first 10 to 14 days. In addition, your dog should avoid bathing or swimming while sutures are in place. He also recommends feeding softened food in gruel or liquid form and not allowing your dog to chew on hard objects. In some cases, a feeding tube may be used to aid recovery and ensure the dog is receiving adequate nutrition, he says.
Post-Surgery Prognosis and Quality of Life
Outcomes can vary, but most dogs return to eating normally in three to five days, especially following a partial maxillectomy, Dr. Klein says. The following changes to their cosmetic appearance may be observed:
- Minimal degree of facial deformity with pre-maxillectomy if the canine tooth on the side of surgery is preserved
- Upper lip and lower canine may protrude if the canine tooth is not preserved
- Central, caudal, and hemi-maxillectomies will raise the upper lip, making it shorter and curved inward
- The upper lip moves with breathing for the first 24 to 72 hours
- There will be marked deformity with resection (excision) of both upper canines in bilateral pre-maxillectomy
- They may correct nasal deviation by suturing nasal cartilage to nasal bones
Once these post-surgical complications have subsided or been corrected, and once the dog is able to eat on their own, that dog is expected to have a good quality of life pending a recurrence of any mass or tumor, he adds.
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