Abstract
There has been an increased public interest in orthognathic surgery that has led to many additional surgeries being performed in response to patients’ aesthetic needs. Often procedures such as genioplasty, mandibuloplasty, malarplasty, paranasal augmentation could be done to enhance the aesthetic effects of orthognathic surgery. With these procedures, it is very important to establish clear communication between the patient and surgeon to reduce misunderstandings and to increase patient’s satisfaction after surgery. In this article, we will discuss cases where additional aesthetic surgeries were performed in connection with orthognathic surgery to demonstrate ways that patient facial beauty can be improved.
Introduction
Orthognathic surgery is typically performed to correct malocclusions and for facial esthetics, with the greatest emphasis being on functional occlusion. Therefore, until recently, it was unusual to see orthognathic surgery accompanied by additional aesthetic surgery, but with a heightened awareness of the potential for improved facial aesthetics, additional surgeries such as genioplasty, mandibuloplasty, malarplasty, paranasal augmentation, and other surgical procedures are now being done more frequently.
In this article, various types and methods of additional surgeries to enhance facial aesthetics in connection with orthognathic surgery will be discussed.
Genioplasty
Genioplasty is the most common additional aesthetic surgery and is now considered by many oral and maxillofacial surgeons to be a regular part of orthognathic surgery. The shape and position of the chin are major facial factors in determining a person’s appearance, and with genioplasty, harmony can be achieved in the lower one-third of the patient’s face. This surgery, which changes the shape and/or position of the chin, the tip of the lower jaw, can be performed as a stand-alone procedure or in conjunction with general orthognathic surgery. The operation uses mainly horizontal sliding osteotomy to achieve movement in all directions; from side to side, from anterior to posterior, and from superior to inferior. If necessary, reduction genioplasty may be performed using synthetic materials like silicone or alloplastics such as Medpor® (Porex, Newnan, Georgia) or an autogenous bone graft generated during orthognathic surgery to facilitate simple augmentation.
Preoperative assessment and surgical plan
To establish the desired shape and position of the chin, the patient’s overall facial profile should be analyzed first. In many cases, abnormalities in the chin area often accompany anteroposterior, frontal and vertical abnormalities. However, sometimes a chin might appear to be deformed clinically (pseudo macro/microgenia) even though there are no abnormalities in the chin’s actual position.
Through lateral and posteroanterior cephalograms and cone-beam computed tomography (CBCT) images, an osteotomy line and the direction and amount of movement can be determined based on an assessment of the shape and position of the chin. Several methods of analysis are widely used that identify where the chin is with respect to a facially balanced position, especially relative to the nose and lips. However, the results of this sort of analysis is not absolute, and so the treatment plan should draw on the surgeon’s experience. In addition, the patient’s subjective opinion is important due to the nature of the aesthetic treatment, so it is essential to take the patient’s chief complaint into consideration when establishing the final treatment plan.
Surgical procedures
Incisions should be made between both sides of the canines and horizontally to the vestibular mucosa inferior to the attached gingiva. The incision and detachment should continue along the submucosal tissue to the muscle and periosteum, and then the chin will be exposed. The location of the mental foramen should be checked around the mandibular first or second premolar area and the mental nerve should be carefully detached without any damage. After exposing the chin area, the mid-area of the chin should be marked with a small round bur and guided after the osteotomy of the lower chin. The osteotomy is performed with a reciprocating saw. It is important to not damage the surrounding soft tissue and mental nerve, but to cut both buccal and lingual cortical bone together from beginning to end during the osteotomy. Fragmented bone should then be moved in the intended direction and at that time, an effort should be made to prevent the development of a step between the moved bone segment and the mandible. If a vertical reduction is required, secondary osteotomy and removal should be performed by the necessary amount and the chin should be moved upwards. The bone segment should be moved in the intended direction and fixed using a chin plate and screw. Fixation with a chin plate with four holes and long screws should be sufficient ( Fig. 1 ).
A genioplasty case
A 22-year-old male was treated for mandibular retrognathism with bimaxillary surgery. During the procedure, genioplasty was performed at the same time to improve chin profile. The clinical changes before and after bimaxillary surgery with genioplasty can be seen in Figs. 2–4 .
Mandibuloplasty
The mandible is a protrusion from the face along with the nose. This is an important factor in determining appearance and aesthetics. For Westerners, as their malar bone and mandibular angle are not developed well, there are many techniques for augmentation. In a similar way, for East Asians including Koreans, Chinese, and Japanese, there are many surgical techniques for reduction in these areas because smaller and slimmer faces are preferred. In particular, in favor of a leaner jawline called the “V line”, the mandibular angle is often cut off up to the mental foramen of the mandible and a corticotomy is done during the procedures. Because of this trend, the term “mandibuloplasty” has been used more recently. The development of surgical techniques using an intraoral approach along with the appropriate instruments for the mandibuloplasty have made this a safe surgery that takes a relatively short period of time to perform and it can be done together with orthognathic surgery nowadays.
Preoperative assessments and surgical plans
A prominent mandibular angle, often referred to as a square jaw, is classified as a large mandible or the case of a bulky masseter muscle. Mandibuloplasty is not indicated for the latter. At this point, botulinum toxin can be injected into the muscle to achieve satisfactory results.
Radiographic imaging is usually used to produce posteroanterior and lateral cephalograms and panoramic radiographs. Since mandibular ostectomy is often performed in concert with the other procedures, CBCT imaging is usually taken to evaluate the three-dimensional (3D) positional relationship of the inferior alveolar nerve to assess the possibility of damage during surgery. In addition, because it is often difficult to construct the accurate shape and amount of resection for mandibular angles with two-dimensional analysis, accurate 3D analytical methods with CBCT images and rapid prototyping (RP) models are advisable.
For mandibuloplasty, the gonial angle, mandibular plane angle, and shape of the symphysis should be evaluated. In case of a long face, it is better to not make them steeper. Meanwhile, if only a protrusion of the mandibular angle is resected without any reduction in the width, despite a broad bigonial width, it may be impossible to obtain a satisfactory facial contour of the mandible from the frontal view. Therefore, if the lower face is large due to a wide bigonial, lateral cortical ostectomy for both sides of the mandibular angle might be effective. If the vertical distance is short because of a square facial shape, sometimes it requires gonial angle reduction accompanied by augmentation genioplasty.
Surgical procedures
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Mandibular angle reduction and mandibular body ostectomy
A mucosal incision is made from the midpoint of the vertical distance of the mandibular ramus to the vestibular area posterior to the canine. An osteotomy line should be marked from the center of the mandibular angle to the lower part of the mandibular body using a round bur. Recently, more patients are requesting a slim jawline where the ostectomy line of the mandibular body extends even inferior to the canine. During this procedure, careful attention is essential not to damage the mental nerve. Osteotomy is performed using an oscillating saw with a 10 mm blade. Then, the bone fragment of the mandibular angle should be separated and removed using a curved chisel and mallet.
Angle reduction surgery case
A 23-year-old female was referred for mandibular prognathism with a prominent mandibular angle. At the same time as the mandibular jaw surgery, mandibular angle reduction was performed, too. The clinical changes before and after single jaw surgery with mandibular angle reduction are shown in Figs. 5 and 6 .
