Orthognathic camouflage





Key points


• Skeletal discrepancies leading to malocclusion are frequently treated with compensatory orthodontics.


• Dental compensation of skeletal discrepancies frequently leads to facial imbalance.


• Camouflage procedures may be an option to restore facial harmony without the need for orthognathic surgery.


• Procedures such as rhinoplasty, genioplasty, or alloplastic implantation are options to restore skeletal balance.


• Dermal fillers, dermal fat grafts, and autologous fat grafting are excellent options to restore soft tissue dimensions.


Introduction


Some patients may present with a skeletal facial anomaly that would ideally be treated with orthognathic surgery but do not wish to undergo jaw surgery. In these cases, orthognathic camouflage procedures may be offered as an alternative option. Orthognathic camouflage refers to the use of procedures other than traditional orthognathic surgery to correct facial dysmorphology created by an underlying skeletal discrepancy. Potential indications for a camouflage procedure include a dentally compensated skeletal discrepancy, hemifacial microsomia, posttraumatic jaw deformity, and iatrogenic deformity resulting from previous surgery.


The most common indication for a camouflage procedure is an underlying skeletal malocclusion that has been treated with dental compensation. Dental compensation can be used to treat class II or III malocclusions without surgery in many cases. However, to make room to align teeth in a class I position, other teeth may need to be extracted. It is important to speak with every patient about the underlying etiology of his or her concern (jaw imbalance) and present orthognathic surgery as an option. Additionally, every patient should be questioned about snoring to find out if there is evidence of sleep apnea. If a full sleep assessment reveals underlying obstructive sleep apnea, the correction of the apnea is an important consideration in developing an optimal treatment plan.


Skeletal class II deformity


Underdevelopment of the lower jaw leading to a class II malocclusion is the most common skeletal discrepancy. , Ideally, treatment consists of lower jaw advancement with or without genioplasty. However, many of these patients seek orthodontic treatment in their early teens, and surgery seems to be an overly aggressive approach at that time. Therefore the orthodontist will typically offer a treatment that can achieve class I occlusion without the need for surgery. To align teeth when class II malocclusion exists, premolars are frequently extracted in the upper arch allowing the anterior teeth to be posteriorly positioned. As the upper teeth tilt posteriorly, the lip support falls posteriorly as well. Given that the original underlying abnormality is a small lower jaw, the patient now presents with a small lower jaw and chin as well as a retracted upper lip. The loss of upper lip support compounded by a small lower jaw frequently gives the appearance of a large nose even when nasal dimensional analysis shows that the nasal dimensions are within normal limits. Although the orthodontist has achieved an excellent occlusion, facial form is severely compromised ( Fig. 25.1 ).




Fig. 25.1


This patient presented for a rhinoplasty to reduce the size of her “large” nose (A, B). This is an excellent example of a skeletal jaw problem being treated with orthodontics. The patient has a class I dental occlusion, but her mandible is retrognathic. The orthodontist pulled the upper incisors posteriorly to align them with the lower incisors, thus allowing the upper lip to fall back and give the appearance of a large nose. Because the underlying etiology is mandibular retrognathia, the chin appears weak, causing the appearance of a large nose. The patient was treated with rhinoplasty and chin advancement to balance the facial proportion and improve the relationship between the nose and the chin (C, D).


The dentally compensated patients with class II malocclusion represent a large percentage of those who present to the surgeon’s office to reduce their “big” nose and increase their chin projection. The number of patients presenting for chin augmentation and reduction rhinoplasty demonstrates how frequently this situation is encountered. A frequent complaint of the rhinoplasty patient is “my nose is too big.” When nasal analysis is performed relative to the upper face, the nose may be of normal dimension; the perceived appearance is caused by a deficient chin, not a large nose (see Chapter 29 ). Chin augmentation is performed to create the appearance of a normal jaw relationship without the need for jaw surgery; simply advancing the chin may make the “large” nose appear normal. In cases where the patient feels that the nose is too large despite chin advancement, a rhinoplasty is performed in addition to chin advancement (see Fig. 25.1 ).


Additionally, with aging, the dentally compensated patient with class II malocclusion will be susceptible to early skin laxity secondary to the lack of skeletal support. It is not uncommon for these patients to present for procedures such as neck lift and facelift earlier compared with their peers who have normal skeletal relationships. The profound benefit of skeletal support on the soft tissues of these patients is seen in the cases described in Chapter 27 on genioplasty; these patients undergo genioplasty at a later age for perioral rejuvenation. In these cases, an osseous genioplasty may achieve an aesthetic result superior to that of a neck lift.


The initial visit of the patient with class II malocclusion should include obtaining any history of snoring and examination of the occlusion. If snoring is reported, a full sleep examination, including a formal sleep study, may be necessary to determine whether formal orthognathic surgery is indicated before chin surgery. Additionally, if class II malocclusion is noted in a patient, that is, if dental compensation has not been performed, sagittal split advancement should be discussed with the patient as a surgical option (see Chapter 22 ). The patient may not wish to proceed with jaw surgery or may resist undergoing a sleep study, but it is important for the physician to document that these conversations have taken place before proceeding with chin augmentation. During physical examination, it is important to look at the acuity of the labiomental crease. If there is a retrusive chin with a normal labiomental crease, the retrusion is likely due to an underdeveloped jaw rather than an underdeveloped chin. In contrast, if there is an obtuse labiomental angle, the lower jaw may be in a more normal position, and the abnormality may be due to a retrusive chin. The latter is more amenable to chin advancement surgery. The specifics of chin surgery can be found in Chapter 27 .


When it has been determined that the patient is a suitable candidate for chin augmentation, the surgeon may use either osseous genioplasty or a chin implant to achieve the desired goals. Frequently, the nose as well as the chin is assessed to optimize the profile.


The sagittal projection of the chin may be determined by using several methods. Byrd has described a method wherein a line is dropped inferiorly from the middorsum of the nose and tangential to the upper lip. Assuming that the nose is of normal length, the chin should be about 3 mm posterior to this line. Another method is to drop a line inferior and perpendicular to the Frankfurt horizontal (FH) plane that is tangential to the lower lip. The chin should be just posterior to this line in females and at or slightly anterior to it in males. A final analysis uses the Riedel line. This line connects the most prominent points of the upper and lower lips. The most prominent point of the chin should be the third point on this line.


Skeletal class III deformity


Patients may present with a dentally compensated class III skeletal relationship, and camouflage is an option in these patients as well. When evaluating these patients, it is important to inquire about a history of severe snoring or sleep apnea. If sleep apnea is present, a formal evaluation should be undertaken. If the patient is not a candidate for continuous positive airway pressure (CPAP) and obstructive sleep apnea is present, a treatment plan for orthognathic surgery should be recommended.


On physical examination, the entire face is assessed. The projection of the infraorbital rims should be assessed to see if they lack projection creating a negative factor globe relationship. The midface and perialar areas are assessed next. A typical presentation includes deep alar grooves, shallow midface projection, and deep nasolabial creases. The chin is assessed to see if it is projecting beyond the lower lip. Although the deficiency lies in the midface, a strong chin that is posteriorly positioned can soften the degree of midface retrusion when midface camouflage is also performed.


Surgical options to camouflage the dentally compensated skeletal class III relationship include the use of alloplastic implants, fat grafting, and dermal fillers. If a shallow orbital rim is present and there is a negative vector that concerns the patient, a transconjunctival incision can be made and an inferior orbital rim implant placed, thus adding projection to the rim. , The authors prefer a transconjunctival incision with cantholysis laterally and a slight skin extension into a crease near the “crow’s feet” area. This offers ample exposure to place a polyethylene implant along the inferior orbital rim. The implant is secured with one or two self-drilling titanium screws that are placed posterior to the rim on the anterior portion of the orbital floor to minimize palpation by the patient. The use of a transconjunctival incision with reattachment of the canthus is well concealed and results in good symmetry of the lower lid.


Other approaches to treating inferior orbital rim deficiency include fat grafting or dermal filler. It is the authors’ preference to avoid autologous fat grafting in this area, given the thin tissue that is associated with this anatomic region. The margin for error between an adequate fill and the visible irregularities that the patient can see or feel is small. If the soft tissue filler is to be used, the author prefers using hyaluronic acid. Below the lid–cheek junction, hyaluronic acid products with greater G prime (elasticity) have been shown to achieve effective results. However, in the thin lower lid tissue, it is preferable to use low-viscosity filler to aesthetic goals with a lower likelihood of complications. An alternative approach is to place the filler deep and lift from below, rather than placing it intradermally.


Midface deficiency is treated with dermal fillers or insertion of alloplastic implants. The advantage of an implant is that it is permanent, but it is more useful for more pronounced deficiency and requires a surgical procedure. Alternatively, dermal fillers allow more subtle degrees of augmentation, more precision, and avoid the need for surgery. The use of fillers is described in Chapter 36 .


Alloplastic implants are a useful tool in midface camouflage. Implants come in a variety of shapes and sizes and can be tailored to the individual’s specific needs. Placement is usually done through an intraoral incision, and the implant is then secured with two titanium screws to prevent rotation and to affix the implant directly to bone. Firmly securing the implant to bone eliminates any space between the implant and bone, thus improving the accuracy of the result. The authors’ preference is to do each side individually to reduce intraoral contamination on each site. Chlorhexidine mouth rinse (Peridex) is allowed to sit in the mouth, with a saturated sponge is left in place for 5 minutes before incision. Epinephrine is also injected 10 minutes before incision to make sure that there is a dry field facilitating the efficiency of the surgery. The details of this technique can be found in Chapter 24 .


Fat grafting has been used successfully in areas of midface augmentation, and in many patients, this can be used instead of an alloplastic implant or be used as an adjunct to the soft tissue overlying the alloplastic implant. To achieve the desired form and texture, the authors recommend using an implant that is slightly smaller in size than necessary to achieve an ideal contour with an implant alone. The use of a slightly smaller implant and autologous fat yields a result with a soft natural texture in addition to the desired form.


Hemifacial microsomia


Patients presenting with hemifacial microsomia demonstrate both skeletal and soft tissue facial deficiencies. Typically, treatment includes bimaxillary surgery as well as genioplasty and associated soft tissue augmentation. Some patients who present with these findings, however, have a minimal occlusal cant or are unwilling to undergo jaw surgery and desire cosmetic improvement. In selected patients, orthognathic camouflage may be a surgical option.


While obtaining a thorough history and during the subsequent discussion with the patient, two-jaw surgery and chin surgery should be recommended as the ideal option. If the patient does not agree to proceed with jaw surgery but is still looking for an improvement, other options can be discussed. On physical examination, it is important to note any midline dental deviations or skeletal deviations. Additionally, the presence and severity of an occlusal cant should be documented, and the patient should be informed that neither the occlusal cant nor a midline deviation can be corrected without orthognathic surgery (see Chapter 22 ).


If the patient is a candidate for a camouflage procedure, a treatment plan that addresses both the skeletal and soft tissues is developed. It is not uncommon for the patient to exhibit deficiency of the inferior orbital rim. Similar to the midface deficiency seen in a class III deficiency, an orbital rim implant can be placed to improve skeletal symmetry. The anterior malar region and the anterior maxilla can also be addressed with an alloplastic implant to augment skeletal deficiency. Fat grafting can then be placed over the implants in the deep subcutaneous tissue to add soft tissue volume over the implants. Autologous fat achieves not only symmetrical form but symmetry of texture as well ( Fig. 25.2 ). The mandibular angle is also an important area that needs to be addressed to achieve symmetry in the patient. Again, fat grafting is a very useful tool to create symmetry in both form and texture. In many cases, the authors intentionally select an alloplastic implant that is smaller than the skeleton on the contralateral side so that the final contour is achieved with fat over the implant. This may take more than one session of fat grafting, but it allows the surgeon the ability to fine-tune the tissue contour with a permanent biocompatible material that has a soft natural feel for the patient ( Fig. 25.3 ).


Apr 1, 2021 | Posted by in Aesthetic plastic surgery | Comments Off on Orthognathic camouflage
Premium Wordpress Themes by UFO Themes