The chin represents an often underappreciated aesthetic component of the face; however, the chin remains an essential facial subunit that plays a significant role in the overall attractiveness of the face. Chin augmentation, or genioplasty, is a common facial plastic surgery procedure used to improve facial aesthetics. To fully appreciate the effects that chin augmentation can provide for the patient, the surgeon must perform a complete facial evaluation and possess a thorough understanding of the relevant anatomy. Although several methods exist to augment the chin, including osseous genioplasty, this article will focus specifically on chin augmentation using alloplastic chin implants.
Structures Encountered During Alloplastic Chin Implantation
Anatomic Structures at Risk
Chin implantation is mostly used in conjunction with rhinoplasty to create a harmonious nose-chin relationship and aesthetically pleasing profile and may be indicated in up to 25% of patients presenting for cosmetic rhinoplasty. Chin augmentation can significantly improve the results of a facelift by lengthening the jawline and providing a better framework in which to reposition the soft tissues of the face.
A relative contraindication may include:
The ideal alloplastic implant for augmentation should have the following characteristics:
The most common alloplastic implant materials used for chin augmentation consist of:
Depending on a number of factors (patient's pain threshold, patient anxiety, patient overall health, the complexity of the procedure, surgeon comfortability and skill level, etc.) a chin augmentation with an alloplastic implant may be done either under local anesthesia (with or without oral anxiolysis and analgesia) or via deeper sedation or general anesthesia.
Personnel needed for the procedure performed under local anesthesia:
Personnel needed for the procedure performed under deep sedation or general anesthesia:
A comprehensive evaluation of the chin should be performed in three-dimensions with the vertical (superior-inferior), horizontal (anterior-posterior), and transverse dimensions recognized. In addition, the chin position relative to the lips, teeth, maxilla, nose, and soft tissues of the neck should be taken into account. Often, photographic analysis is sufficient for minor deformities that will require an alloplastic implant; however, if the deformity is more significant (e.g., vertical height excess or transverse asymmetry), a radiograph is often warranted.
Several techniques exist to help evaluate those patients who may benefit from a chin augmentation:
Lastly, two well-described facial angles required for complete chin analyses include the cervicomental angle (CMA) and the mentocervical angle (MCA).
While all of these methods offer insight as to an ideal chin position relative to the lips, face, and even neck, only a limited number take into account the relationship between the nose and chin. This is an important relationship not to overlook as they directly correlate to each other’s relative appearance in space, with the general rule being that the more projected the nose, the less projected the chin appears to be and vice versa. Furthermore, it is important to recognize that all of the analysis methods mentioned are based on standardized photography methods, four of which rely on the Frankfort horizontal line, which is a well-known anatomic horizon extending from the superior border of the external auditory canal to the inferior orbital rim. Furthermore, radiographic evaluation in the form of a panoramic radiograph and/or lateral and AP radiographs may be useful for more complex deformities such as vertical height excess, orthognathic deformities, and transverse asymmetry as seen in hemifacial microsomia, oculoauricular vertebral (OAV) syndrome, or even as an isolated component of the anatomy.
Once the patient is deemed a candidate for an alloplastic implant, and the type and size of the implant are selected, the decision must be made whether to perform the procedure via an intraoral or submental approach. In short, the transoral approach has the benefit of no external scarring; however, the procedure is technically more difficult and is associated with increased risk of infection given the communication with the oral cavity. The submental approach, on the other hand, is often preferred for several reasons in that it offers better exposure for placement as well as access to the neck for any additional procedures to be performed (e.g., concomitant facelift, neck lift, platysmaplasty, liposuction).
Submental transcutaneous approach:
NOTE: While not part of this discussion, it would be prudent for those who routinely encounter patients with microgenia or retrognathia and who perform chin augmentation to have a sound understanding of the anatomy and principles relevant to sliding genioplasty as well.
Generally speaking, chin augmentation using alloplastic implants(via a transoral or subcutaneous approach) represents a relatively straightforward procedure with a low-risk profile and a high (97.8%) satisfaction rate.
Tips to avoid complications have been elucidated above, but include:
NOTE: While not routinely used, some authors advocate using screw fixation to prevent the migration (secondary displacement) of an implant.
An alloplastic chin implant is used to augment chin projection and can be used to provide a more attractive appearance of the face. Increasing the projection and/or width of the chin to provide a more balanced nose-chin relationship or more pleasing pre-jowl area, respectively, are two examples where this is especially apparent. When performing an alloplastic chin implantation, a comprehensive understanding of the anatomy and precise surgical technique are essential to achieving optimal results.
Before performing an alloplastic chin augmentation procedure, it is important to perform a thorough preoperative assessment and identify any potential risk factors specific to the patient. A team approach is always ideal to ensure the procedure is performed to the highest possible standards. Prior to surgery, the patient should have the following done:
An interprofessional team consisting of personnel experienced in chin implantation (e.g., surgeon, anesthesiologist, surgical assistants, operative nurses, etc.) should perform the alloplastic chin implantation for the best outcomes. If performed in the clinic, a nurse fully dedicated to monitoring the patient (particularly if using sedation) is strongly recommended. A close follow-up should be scheduled in the post-operative period to ensure there are no signs of infection, hematoma, or rejection that occur. The patient should also be educated on avoiding strenuous activity, heavy lifting, or stooping over within the first week post-operatively to prevent complications. By following these basic steps, outcomes should be favorable when performing alloplastic chin implantation. [Level 5]
Recovery time can be reasonably expected to take 3 to 5 days for most individuals, though swelling and bruising may persist for up to 2 weeks, depending on the extent of the surgery. Pain is typically mild to moderate; however, over-the-counter analgesics (e.g., acetaminophen 1000 mg every 8 hours as needed for pain) may be supplemented with prescription-strength medication per physician and patient preference. Post-operative antibiotics (with oral flora coverage) may be given for 5 to 7 days and is strongly encouraged if a transoral approach was used. The patient is instructed to eat a soft diet, keep the head elevated, routinely apply ice to the area, employ good oral hygiene (e.g., salt water rinses before and after meals), and avoid strenuous activity for two weeks — patients follow-up in roughly seven days for wound assessment and suture removal. Photographic documentation may take place at the 3-month visit.
Regardless of where the procedure is to be performed (clinic, hospital, surgery center), a recovery nurse fully dedicated to monitoring the patient is strongly recommended to detect serious complications such as hematoma formation. Close follow-up within 1 week should be scheduled in the clinic in the post-operative period to ensure there are no signs of infection, hematoma, or rejection.
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