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The Diagnosis and management of facial asymmetry
Journal of Oral Biology and Craniofacial Research 7 (2017) 1
Contents lists available at ScienceDirect
Journal of Oral Biology and Craniofacial Research journal homepage: www.elsevier.com/locate/jobcr
Editorial
The Diagnosis and management of facial asymmetry [TD$INLE]
Facial asymmetry is, of all the non syndromic facial abnormalities the one that causes the most distress to patients. In all the studies that attempt to quantify the impact of facial differences asymmetry rates the highest. Cross-sectional imaging technology, cone beam CT scanning and the use of CADCAM techniques are now routine in the management of these patients. These technologies allow for on screen surgical rehearsal, the trial of different operative plans, the use of mirror imaging, the manufacture of cutting guides and patient specific implants as well as the printing of stereolithographic models. Whilst modern technology has revolutionised the way in which surgery for asymmetry can be planned and executed there are a number of fundamental diagnostic dilemmas that need to be resolved irrespective of the type of planning system and aids utilised. From the history it is important to identify whether the condition is progressive or static. In order to help make this decision obtaining photographs, previous dental casts and considering the use of nuclear medicine scans are all helpful. In the overall assessment of the patient the clinical examination is critical: many patients with a facial asymmetry, particularly if this involves a dystopia will tilt their head to correct the visual plane. This tilt occurs instinctively and a key decision that needs to be made is whether this tilt will be corrected or not. Dystopia corrections with raising or lowering the orbital level often involve a transcranial procedure. In addition to the head tilt some patients may have cervical spine abnormalities that also can contribute to, or be part, of the of the asymmetry. Movement of the cervical spine requires assessment as untreated torticollis can also lead to facial asymmetry associated with skull base torsion as well a pan- facial asymmetry.
The skull should be assessed to exclude an untreated single suture synostosis such as a unicoronal synostosis which may also cause a pan-facial asymmetry. Positional skull deformities, which cause so much parental anxiety as infants, very rarely cause facial deformity that requires any intervention in adulthood and although there is often some residual skull deformity it almost never warrants intervention. The ear shape, size and position should be recorded. Whilst examining the asymmetrical patient it may seem absurd but a key decision is to assess which side of the face represents the abnormality, though in reality, often there are abnormalities on both sides. The rest of the body should also be examined for asymmetries in limb length and size. The hard tissue anatomy should be examined and assessed in the three planes, vertically, horizontally (anteroposteriorly) and transversely as well as for pitch and yaw. These assessments should be applied to the forehead, orbits, cheekbones, maxillae, mandible and chin. Dental and occlusal assessments are also necessary. The soft tissue assessment needs to address the static and dynamic state of the overlying soft tissues. All the cranial nerves should be examined. Low flow venous malformations often swell when dependent and this should be considered when examining the patient. Once complete clinical examination has been made the clinician should be able to quantify and delineate the site, extent and balance between hard and soft tissues that contributes to the facial asymmetry. This will allow for the formulation of a differential diagnosis and guide in obtaining the most appropriate investigations. Once the diagnosis has been confirmed and the abnormality characterised the treatment planning can start. There will inevitably be a number of choices often with varying degrees of complexity. In general a total correction should be offered in the first instance with compromises and camouflage procedures offered later in the discussion. The management of facial asymmetry present significant challenges, the advent of modern imaging and cadcam planning techniques as well as patient specific implants have improved our ability to diagnose and treat this challenging group of patients immeasurably. All of these techniques remain as tools to implement the best plan for the individual patient being treated. Deciding on treatment objectives and the steps to get there still presents significant challenges, even for the experienced clinician, and the choices that need to be made are underpinned by a clear understanding of the patients concerns and objectives, the pathophysiology of the aetiology, the balance between soft tissues and hard tissues and finally the three dimensional relationship between all the different components that contribute to the asymmetry. David A Koppel
http://dx.doi.org/10.1016/j.jobcr.2017.02.002 2212-4268/ß 2017 Published by Elsevier B.V. on behalf of Craniofacial Research Foundation.
Contents lists available at ScienceDirect
Journal of Oral Biology and Craniofacial Research journal homepage: www.elsevier.com/locate/jobcr
Editorial
The Diagnosis and management of facial asymmetry [TD$INLE]
Facial asymmetry is, of all the non syndromic facial abnormalities the one that causes the most distress to patients. In all the studies that attempt to quantify the impact of facial differences asymmetry rates the highest. Cross-sectional imaging technology, cone beam CT scanning and the use of CADCAM techniques are now routine in the management of these patients. These technologies allow for on screen surgical rehearsal, the trial of different operative plans, the use of mirror imaging, the manufacture of cutting guides and patient specific implants as well as the printing of stereolithographic models. Whilst modern technology has revolutionised the way in which surgery for asymmetry can be planned and executed there are a number of fundamental diagnostic dilemmas that need to be resolved irrespective of the type of planning system and aids utilised. From the history it is important to identify whether the condition is progressive or static. In order to help make this decision obtaining photographs, previous dental casts and considering the use of nuclear medicine scans are all helpful. In the overall assessment of the patient the clinical examination is critical: many patients with a facial asymmetry, particularly if this involves a dystopia will tilt their head to correct the visual plane. This tilt occurs instinctively and a key decision that needs to be made is whether this tilt will be corrected or not. Dystopia corrections with raising or lowering the orbital level often involve a transcranial procedure. In addition to the head tilt some patients may have cervical spine abnormalities that also can contribute to, or be part, of the of the asymmetry. Movement of the cervical spine requires assessment as untreated torticollis can also lead to facial asymmetry associated with skull base torsion as well a pan- facial asymmetry.
The skull should be assessed to exclude an untreated single suture synostosis such as a unicoronal synostosis which may also cause a pan-facial asymmetry. Positional skull deformities, which cause so much parental anxiety as infants, very rarely cause facial deformity that requires any intervention in adulthood and although there is often some residual skull deformity it almost never warrants intervention. The ear shape, size and position should be recorded. Whilst examining the asymmetrical patient it may seem absurd but a key decision is to assess which side of the face represents the abnormality, though in reality, often there are abnormalities on both sides. The rest of the body should also be examined for asymmetries in limb length and size. The hard tissue anatomy should be examined and assessed in the three planes, vertically, horizontally (anteroposteriorly) and transversely as well as for pitch and yaw. These assessments should be applied to the forehead, orbits, cheekbones, maxillae, mandible and chin. Dental and occlusal assessments are also necessary. The soft tissue assessment needs to address the static and dynamic state of the overlying soft tissues. All the cranial nerves should be examined. Low flow venous malformations often swell when dependent and this should be considered when examining the patient. Once complete clinical examination has been made the clinician should be able to quantify and delineate the site, extent and balance between hard and soft tissues that contributes to the facial asymmetry. This will allow for the formulation of a differential diagnosis and guide in obtaining the most appropriate investigations. Once the diagnosis has been confirmed and the abnormality characterised the treatment planning can start. There will inevitably be a number of choices often with varying degrees of complexity. In general a total correction should be offered in the first instance with compromises and camouflage procedures offered later in the discussion. The management of facial asymmetry present significant challenges, the advent of modern imaging and cadcam planning techniques as well as patient specific implants have improved our ability to diagnose and treat this challenging group of patients immeasurably. All of these techniques remain as tools to implement the best plan for the individual patient being treated. Deciding on treatment objectives and the steps to get there still presents significant challenges, even for the experienced clinician, and the choices that need to be made are underpinned by a clear understanding of the patients concerns and objectives, the pathophysiology of the aetiology, the balance between soft tissues and hard tissues and finally the three dimensional relationship between all the different components that contribute to the asymmetry. David A Koppel
http://dx.doi.org/10.1016/j.jobcr.2017.02.002 2212-4268/ß 2017 Published by Elsevier B.V. on behalf of Craniofacial Research Foundation.