Imaging of cosmetic facial implants and grafts

Evaluation of the effect of chin prosthesis implantation on mentalis muscles based on three-dimensional imaging technology

BACKGROUND

Chin prosthesis implantation, a cosmetic procedure to correct chin asymmetry, depression, or retraction, is generally safe and simple. However, its long-term effects on surrounding tissues are a concern. This study aimed to use three-dimensional (3D) scanning to classify the mentalis muscle shapes and assess the impact of prosthesis implantation on these muscles.

METHOD

This study evaluated 450 eligible female participants. Using three-dimensional imaging, data on the types, thickness, width, and length of the left and right mentalis muscles were collected and summarized. The impact of chin prosthesis on these muscle dimensions was assessed using analysis of variance, and the effect on muscle type was determined using χ2 test.

RESULTS

Chin implant placement affected the mentalis muscles, resulting in increased length, thickness, and width. The subjects' mentalis muscles were categorized into 3 types and divided into 7 subtypes. χ2 test results indicated that implantation influences the classification of these muscles.

CONCLUSION

Recognizing how implant placement affects the mentalis muscle can guide the development of treatments to mitigate these changes. Additionally, understanding the muscle's morphology enables more precise treatment approaches for patients.

Imaging Features and Complications of Facial Cosmetic Procedures

Facial aesthetic procedures have become increasingly popular and complex, making knowledge of facial anatomy crucial for achieving desired outcomes without complications. Some of the most common procedures include blepharoplasty, bichectomy, face-lifts, facial implants, thread lifting, and fillers. Blepharoplasty and bichectomy are surgical procedures that respectively aim to restore youthful contours to the periorbita and create a slimmer lower face by removing Bichat fat from the maxillofacial region. Facial implants are used for aesthetic augmentation of the skeletal structure and restoration of facial contour by using biomaterials or autogenous bone grafts. Face-lift surgeries involve incisions and removal of excess skin, and thread lifts involve less invasive procedures performed by inserting threads beneath the skin, with the aim to lift the skin and thus reduce wrinkles and sagging. Fillers improve wrinkles and loss of facial volume, with biologic types made from animal, human, or bacterial sources (such as hyaluronic acid), while synthetic fillers include substances such as paraffin, silicone, calcium hydroxyapatite, polymethylmethacrylate microspheres, polyacrylamide hydrogel, hydroxyethyl-ethyl methacrylate, and poly-l-lactic acid. Synthetic fillers can be classified as rapidly resorbable (<12 months), slowly resorbable (<24 months), or permanent. Imaging modalities such as US, CT, and MRI can help identify and analyze each type of facial aesthetic procedure or filler, as well as their possible complications such as foreign-body granuloma, noninflammatory nodule, late intermittent persistent edema, filler migration, infection, or complications after removal of the buccal fat pad. ©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center The online slide presentation from the RSNA Annual Meeting is available for this article.

A Curious Case Report: Should a Clinician Be Worried About Bone Resorption Under a Chin Augmentation Site?

Oftentimes patients are concerned about their facial esthetics and appearance. To achieve the desired look, patients have several augmentation procedures available to them. Appearance of the chin and its morphology plays a crucial role in facial aesthetics. It is an important anatomic component that not only helps in the definition of the jawline and face but is also required from a functional aspect. It is not uncommon in the field of plastic surgery for patients to undergo chin reconstruction and recontouring due to the chin deformities such as microgenia and jaw asymmetry. The treatment options mainly depend on the degree of the defect and the desired functional and esthetic requirements. Along with surgical augmentations like implants and osseous genioplasty, soft tissue augmentations like injectables are also gaining popularity. These procedures can lead to complications like many other augmentation procedures. If proper follow-up is not done on these patients, the complications can cause potential damage to vital structures in the vicinity. This case report shows a patient who underwent a chin augmentation procedure with a silastic implant and never had a follow-up and is now at risk of severe resorption of the underlying bone.

Imaging of Malar Silastic Implant Complications

Facial cosmetic implants are utilized for definition enhancements in the malar, mandibular, and nasal regions. Though these implants are safe in the majority of patients, notable complications such as implant malpositioning may be seen. More rare but serious complications such as infection, abscess, and intrasinus migration may also occur, such as in this case reported on a 69-year-old female with a history of bilateral malar silicone implants. Imaging findings on this patient, whom initially presented with complaints of erythema and edema in the left malar region, were notable for edema and soft tissue signs of infection around a well-visualized crescent shaped maxillary implant. Penetration of the implant into the left maxillary sinus was also noted. Diagnostic imaging played a key role in determining the cause and severity of this patient's condition. Thus, the case reported is with an aim to familiarize radiologists with identifying and interpreting the complications of malar cosmetic implants on diagnostic imaging.

A case study of an undetected expanded polytetrafluoroethylene implant material mimicking a nasal dorsal hump

Augmentation rhinoplasty using alloplastic materials is a relatively standard procedure in Asian patients. Expanded polytetrafluoroethylene (ePTFE) is one of the commonly used alloplastic materials because it has a high biocompatibility and is easy to handle. Recently, a patient who had previously undergone augmentation rhinoplasty using ePTFE as the implant material visited our clinic. She had the implant material surgically removed after three years and visited our clinic with a nasal dorsal hump. The patient underwent revision rhinoplasty at our institution. Unexpectedly, we found some ePTFE material that was not identified on the preoperative X-rays. After removing the ePTFE material, the nasal dorsal hump was corrected, and we did not need to perform a nasal dorsal hump reduction.

INFECTED SILICONE CHIN IMPLANT AFTER IMPLANT-SUPPORTED JAW REHABILITATION: CASE REPORT AND LITERATURE REVIEW

To report the infected silicone chin implant due to the non-ideal placement of dental implants, in female patient, 67 years old. A patient unsatisfied with her facial profile had installed a silicone chin implant 25 years ago. Recently underwent surgery for the placement of dental implants in a region close to the silicone implant. The non-ideal positioning of the dental implants and close contact with the silicone implant led to the absence of osseointegration, with consequent mobility and infection of both. The silicone implant was removed with dental implant that shows mobility. In the imaging exams could be noted others complications of silicone implant like bone resorption and the formation of a narrow bone layer around the inferior border of implant. Alloplastic implants are an option for the esthetic correction of chin deformities. Solid silicone is biocompatible and highly resistant to degradation, with a minimal allergic reaction and risk of toxicity. However, a number of postoperative complications may arise, such as migration or displacement, extrusion, foreign body reaction, bone resorption, heterotopic bone formation and infection. The precise imaging exams are critical to arrive at a diagnosis and the best treatment plan.

Radiologic Findings of Complicated Alloplastic Implants in the Nasal Dorsum

Objectives

When performing cosmetic rhinoplasty with alloplastic materials, complications such as implant visualization, inflammation, dislocation, and extrusion should be thoroughly evaluated. Although computed tomography (CT) can provide useful information about the implant status and its interaction with the skin soft tissue envelope (SSTE), the radiologic findings of these interactions have rarely been reported.

Methods

We retrospectively reviewed the data of 80 patients who underwent facial bone CT or ostiomeatal unit CT at Asan Medical Center between July 2008 and January 2020 for the evaluation of dorsal implants with complications. We reviewed the implantation period, implant dislocation, implant curling or deformation, radiodensity (in Hounsfield units), and nasal bone changes including bone erosion or hyperostosis.

Results

Of the 80 patients, 67 (83.8%) had silicone implants and 13 (16.2%) had Gore-Tex implants. The radiologic findings of the silicone implants were as follows: maintenance of the implant shape (80.6%), radiolucency (similar density to that of fat tissue) halo (83.6%), and homogeneous attenuation (82.1%). Peri-implant calcification was often found in silicone implants with >20-year implantation periods. The findings of Gore-Tex were as follows: curling or deformation (84.6%), heterogeneous attenuation (84.6%), and consistent peri-implant calcification over time.

Conclusion

Silicone and Gore-Tex implants have distinctive radiologic features. These findings of alloplastic materials help us to understand how implants behave in the nasal dorsum and how they affect the SSTE.

Ten must know pseudolesions of the head and neck

Patients may present in the emergency setting for a variety of head and neck complaints such as fever, trouble swallowing, or a newly palpable mass. When reviewing radiologic head and neck exams for etiology of complaints, it is important to be familiar with the multiple pseudolesions that may mimic pathology. These may be normal variant anatomy, normal anatomy located in an atypical location, as well as iatrogenic or self-introduced foreign bodies. This review article discusses ten common pseudolesions encountered in the head and neck and their typical imaging appearance so that one does not mistake them for ominous pathology, thus preventing unnecessary follow-up, biopsy, or continued concern for the patient.

Patient-Specific Augmentation Rhinoplasty Using a Three-Dimensional Simulation Program and Three-Dimensional Printing

Background

The convergence of three-dimensional (3D) simulation, tissue engineering, and 3D printing technology is creating a paradigm shift in plastic surgery. In augmentation rhinoplasty, determining the ideal material and design method has been a critical issue for many years. Thus, these technologies are expected to make important contributions to augmentation rhinoplasty.

Objectives

We sought to validate the feasibility of the 3D carving simulation and patient-specific implant fabrication system (3D carving system) in a clinical trial using reproducibility tests.

Methods

Patient-specific implants were designed using a program developed in-house with preoperative computed tomography (CT). Negative molds of the implant were fabricated by a 3D printer and silicone was injected into these molds. Ten actual silicone implants were fabricated and compared with virtually designed implants. Seven patients underwent surgery and postoperative CT to confirm implant positioning.

Results

Virtually designed implants were produced into actual implants within 0.07 mm with a 0.17% ± 0.11% difference. The percentage within the gap was the highest at the cephalic end of the implant and reduced from the cephalic to caudal end (most cephalic point: 100%; rightmost and leftmost point of the implant at the caudal end of the nasal bone: 57.1% and 71.4%, respectively; rightmost and leftmost point at the supratip break: 28.6% and 28.6%, respectively; and most caudal point: 0%).

Conclusions

The 3D carving system can facilitate rhinoplasty by enabling the more intuitive, rapid, and accurate fabrication of implants irrespective of surgeon experience level.

Level of Evidence

4.

Intrasinus penetration of a silastic malar implant, which resulted in chronic sinusitis: A case report and literature review

Background:

Malar augmentation is a common cosmetic procedure utilizing silastic materials. We describe an uncommon complication of a silastic implant eroding into the anterior maxillary sinus wall resulting in chronic rhinosinusitis (CRS).

Methods:

A literature review is presented describing the presentation, surgical management and outcome of this uncommon adverse event.

Results:

An 80 year old female with a history of bilateral cosmetic malar implants placed approximately 25 years ago presented to our office with a 4–5 month history of left-sided symptoms consistent with chronic sinusitis, and was found to have intrasinus penetration of her left malar implant. Only one other case series of 5 cases in 4 patients is reported in the literature.

Conclusions:

Intrasinus malar implant migration is a rare complication of malar augmentation. The present experience suggests that removal of the offending foreign body often results in successful symptom resolution.

Long-standing chin-augmenting costochondral graft creating a diagnostic challenge: A case report and literature review

To our knowledge, the imaging features of costochondral grafts (CCGs) on cone-beam computed tomography (CBCT) have not been documented in the literature. We present the case of a CCG in the facial soft tissue to the anterior mandible, with changes mimicking a cartilaginous neoplasm. This is the first report to describe the CBCT imaging features of a long-standing graft in the anterior mandible. Implants or grafts may be incidental findings on radiographic images made for unrelated purposes. Although most are well-defined and radiographically homogeneous, being of relatively inert non-biological material, immune reactions to some grafts may stimulate alterations in the appearance of surrounding tissues. Biological implants may undergo growth and differentiation, causing their appearance to mimic neoplastic lesions. We present the case of a cosmetic autogenous CCG that posed a diagnostic challenge both radiographically and histopathologically.

Internet Access to Advanced 3-Dimensional Software for the Prototyping and Design of Complex and Precise Custom Mandibular Implants

A large percentage of patients with microgenia requesting chin augmentation also exhibit an associated component of micrognathia with either narrow or acutely angled mandibular bodies and/or hypoplasia of the gonial angles. Augmentation of the face and mandible should optimally address all regions of deficiency and can now be customized with a high degree of accuracy using software that can be accessed over the Internet. We discuss the advanced capabilities of merging a sophisticated software system (Geometric Freeform® software; Morrisville, North Carolina) and computed tomography (CT) imaging to design precise, total custom mandibular implants over the Internet without the need for physical modeling. In revision cases, this process also allowed for the implant to be removed and replaced within a single-stage procedure. We retrospectively reviewed 34 cases in an outpatient surgical center and described the preoperative evaluation, imaging protocol, customization process, and surgical procedure for custom mandibular and custom total mandibular augmentation. Between January 2004 and June 2015, 25 patients underwent total mandibular augmentation and 9 had custom extended mandibular angle and body augmentation. All patients received solid silicone rubber implants that were customized using virtual or acrylic prototypes digitally designed via real-time video conferencing. This custom process achieved an enhanced level of satisfaction with an improved ability to achieve symmetry based on quantitative measurements during the interactive design process, alloplastic facial implants can be customized with a high degree of accuracy, precision, and fit by combining the capabilities of 3-dimensional CT and advanced computer design software accessed via the Internet.

Facial reanimation procedures depicted on radiologic imaging

Various facial reanimation procedures can be performed for treating patients with chronic facial nerve paralysis. The radiologic imaging features of static and dynamic techniques are reviewed in this article with clinical correlation, including brow lift, eyelid weights and springs, gracilis free flaps, fascia lata grafts, temporalis flaps, and Gore-Tex suspension slings. Although the anatomic alterations resulting from facial reanimation surgery may not necessarily be the focus of the imaging examination, it is important to recognize such changes and be familiar with MR imaging compatibility of the associated implanted materials. Furthermore, imaging is sometimes used to specifically evaluate the postoperative results, such as vessel patency following free gracilis transfer.

Imaging features of rhinoplasty

SUMMARY

Cosmetic rhinoplasty encompasses a diverse group of procedures, including alteration of the radix, nasal dorsum, nasal tip, and nasal base; premaxillary augmentation; septoplasty; and combinations thereof. Similarly, many different types of grafts and alloplastic materials can be used in cosmetic rhinoplasty, such as cartilage, bone, silicone, porous polyethylene, expanded polytetrafluoroethylene, and calcium hydroxylapatite. Complications of rhinoplasty that can be observed on imaging include retained metallic surgical instrument fragments, infection, implant extrusion, nerve impingement by implants, nasal valve collapse, and implant deformity. Knowledge of the basic surgical procedures and potential complications of cosmetic rhinoplasty is important for adequately interpreting postoperative radiologic imaging studies.