Jaw-sparing and jaw (maxillofacial) reconstruction
Surgical procedures performed with the intention of sparing or reconstructing the jaws may be called jaw-sparing or reconstructive, but could also be referred to as occlusion-sparing or occlusion reconstruction.
In veterinary medicine, salvage surgical procedures are often used to address significantly damaged jaw(s), such as with fractures or extreme bone infection; or when portions of the jaws are removed during oral tumor surgery. Salvage procedures are intended to control the infections as well as the pain caused by diseased tissue but are not intended to address the jaw malocclusion.
Jaw-sparing and reconstructive surgery can prevent or minimize the unfavorable outcomes associated with jaw malocclusion. The primary goals of jaw-sparing and jaw reconstruction are to achieve normal occlusion; rapid return to normal oral function and activities/lifestyle; and prevent chronic pain associated with malocclusion.
Jaw-sparing (occlusion-sparing) and jaw reconstruction surgery requires a solid understanding of the biomechanics of the masticatory apparatus in health and disease. When jaw surgery is required, consulting with an oral surgeon trained in reconstructive techniques can be beneficial.
Jaw-sparing techniques are aimed at preserving and sometimes reinforcing specific areas of the bone considered to be essential in providing support and bone continuity. Using conservative surgical methods is recommended in situations where both addressing the pathology and preserving the occlusion are possible.
Critical defects are significant gaps between bones that can be consequences of major trauma or infection, as well as extensive surgery for tumor removal. Jaw reconstruction may be indicated to restore or improve the structure and function of the jaws. This is because conventional surgical methods to bring together bone fragments are less likely to be rewarding, as they can result in significant misalignment of the jaws (malocclusion) and the gap is less likely to heal properly.
Decisions about jaw-sparing and reconstruction should be made early in the process of planning a surgical intervention to best ensure optimal outcome. Many patients who have had jaw injuries or surgeries that have healed with abnormal occlusion are more difficult to treat because of scar tissue and temporomandibular joint abnormalities that must be overcome and reversed.
Deciding whether jaw-sparing and/or maxillofacial reconstruction is a good option for a patient should also take into consideration the extent and severity of pathology (fracture, infection, tumor), timing (acute or chronic), and whether previous surgery was performed.
Jaw-sparing and reconstruction examples
Maxillary trauma reconstruction
In this photo series, a model has been used to simulate a series of maxillary fractures that may be encountered when pets sustain a blunt or sharp trauma to the face, such as being hit by a car or bitten in the face.
Mandibular tumor reconstruction
Rostral (front of the mouth) mandibular tumor -jaw sparing/reconstruction
This photo series uses a model to demonstrate reconstruction following removal of a major tumor at the front (rostral) parts of the mandibles.
Caudal (back of the mouth) mandibular tumor, involving dorsal aspect (upper half) of the mandible – jaw sparing technique
This photo series uses a model to demonstrate planning a surgical technique to allow minimal disruption to normal occlusion.
Caudal (back of the mouth) mandibular tumor, involving all or most of the width of the mandible – jaw reconstruction
This photo series uses a model to demonstrate reconstruction following removal of a more extensive mandibular tumorwhose surgical removal creates a critical defect.
Oral function refers to the mouth’s role in an animal’s ability to eat, breathe, groom, play, work, and be generally free of pain and disease. Proper alignment of the jaws and teeth (normal occlusion) plays a major role in oral function and quality of life. When jaws are misaligned (malocclusion), oral dysfunction, trauma and further complications with the temporomandibular joint, nasal cavity, and other local anatomy can occur.
In dogs and cats, the right and left upper jaws (the maxillas) are fused to each other at on their entire length at the midline where they meet. The right and left lower jaws (the mandibles) are attached to each other in the front (at the symphyses) and jointed to the skull (TMJ – temporo-mandibular-joint). Normal position of the jaws allows for normal positioning of the teeth.
Jaw (skeletal) malocclusion caused by trauma or surgical interventions can be either acute, meaning that they are addressed immediately; or chronic, meaning that they develop over time (usually several weeks or months). When maxillofacial trauma or oral tumors occur, it may seem reasonable to address the issue at hand, then manage the resulting malocclusion (and its complications) at a later date. The problem with this approach is that acute malocclusions are ideal candidates for reconstruction (guiding the healing in the appropriate position), while chronic malocclusions are often more difficult to address.