Preoperative Radiology and Virtual Surgical Planning.

Virtual surgical planning enables precise surgical planning and translation of this planning into the operating room. Preoperative maxillofacial computed tomography scans are compared to a reference skull to identify desired surgical changes. In facial feminization surgery, these include forehead recontouring/frontal table setback, gonial angle reduction, and possible chin repositioning/reshaping, while in facial masculinization surgery, this includes forehead augmentation and gonial angle/chin augmentation. Cutting and recontouring guides as well as custom implants are then custom manufactured. Common guides include osteotomy guides, depth drilling guides, ostectomy guides, and guides for one/two-piece genioplasty or chin burring. Common implants include mandibular and chin implants.

Injectable Fillers for Lower Face Rejuvenation.

The lower face is an integral component of a beautiful face. Age-related changes in this region are so significant that they are often easily appreciated by patients. The aging process not only includes volume loss or downward fat repositioning, but also soft tissue laxity, skin changes, and even bony resorption. In the lower face, this results in sagging of the soft tissue leading to the formation of jowling, loss of an attractive well-defined jaw line, and a retruded chin. Both surgical and non-surgical options are available to reverse the aging signs; however, the popularity of non-surgical treatment has dramatically increased in last 2 decades.

Esthetic Surgery of the Chin in Cis- and Transgender Patients-Application of T-Genioplasty vs. Single-Piece Segment Lateralization.

Background and Objectives: Correction of lower face asymmetry still remains challenging in maxillofacial surgery. This report describes techniques for the lateral transposition of the symphyseal segment to restore lower face symmetry while maintaining gender-related features in cis- and transgender patients. Materials and Methods: A retrospective review of medical records of 31 patients who attended for esthetic corrective surgery after orthodontic camouflage or orthognathic treatment, or during facial feminization of the lower face between June 2021 and June 2023 was performed. Result: All patients underwent lateralization genioplasty (with or without advancement or setback), either with or without narrowing T-osteotomy supplemented with necessary procedures in order to obtain proper facial balance and desired esthetical effects, such as bichectomy, liposuction, and face and neck lift. The mean asymmetry of the chin was 5.15 mm and was surgically corrected either by single segment lateralization or T-shape narrowing genioplasty depending on the gender and esthetical requirements. No complications were reported. Conclusions: Lateral shift genioplasty serves as a powerful tool in primary and secondary corrective surgery for lower face asymmetry that maintains gender-specific facial features. It may serve either as an additive to orthodontic camouflage or a way to correct previous orthognathic surgery pitfalls. The surgeon performing esthetic genioplasty associated with gender-specific expectations must be trained in facelift and facial liposculpting techniques in order to provide the best results and properly choose the right procedures for the right patients.

Soft-Tissue Response following Genioplasty Combined with Anterior Segmental Osteotomy.

BACKGROUND: The authors' main aim was to analyze soft-tissue response of the chin following genioplasty with anterior segmental osteotomy, which enables optimal surgical planning of genioplasty. METHODS: Sixty-two patients who underwent genioplasty with concomitant anterior segmental osteotomy were divided into three groups depending on the direction of pogonion (Pog) movement: G1 (without sagittal change), G2 (advancement genioplasty), and G3 (setback genioplasty). All genioplasties included height reduction. Hard- and soft-tissue measurements with cephalometry were performed at T1 (before surgery), T2 (after surgery), and T3 (after orthodontic treatment) for the analysis of sagittal and vertical changes. Correlation and regression analyses were conducted to analyze soft- to hard -tissue movement and soft-tissue thickness changes. RESULTS: During the T1 to T2 period, the horizontal soft- to hard-tissue ratio at Pog was 0.85 in G2 and 0.80 in G3, and the vertical ratio at menton (Me) was 0.9 for all groups. The correlation coefficients were 0.64 (G2) and 0.83 (G3) at Pog and 0.9 (all), 0.85 (G1), 0.95 (G3) at Me. There was no significant correlation between initial soft-tissue thickness and soft-tissue response ratio. During the T2 to T3 period, no significant relapses were observed, which demonstrates the stability of anterior segmental osteotomy combined genioplasty. CONCLUSIONS: Clinically and statistically significant soft-tissue responses were demonstrated at Pog and Me. The higher values in G3 in particular suggest that setback genioplasty with anterior segmental osteotomy is an effective treatment alternative to conventional two-jaw surgery in some patients with bimaxillary prognathism with macrogenia. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Osseous genioplasty versus chin implants: early complications and patient satisfaction.

Osseous genioplasty and chin augmentation with implants are the two main treatment options for retrognathia. This retrospective cohort study was performed to compare the prevalence of complications and patient satisfaction following osseous genioplasty and chin augmentation by implant. Eighty patients were included: 38 underwent advancement osseous genioplasty and 42 received chin implants (alloplastic, either Medpor or Silastic) intraorally or extraorally. The patients were assessed for complications 12 months after surgery, including neurosensory disturbances, infection or extrusion, wound dehiscence, and the need for reoperation. Patient satisfaction was evaluated using a visual analogue scale. The infection rate was significantly higher in the chin implant group than in the genioplasty group (P = 0.028). Moreover, dehiscence and the need for reoperation appeared to be more common following chin augmentation with implants. However, there was no significant difference in the prevalence of neurosensory disturbances between the two groups (P = 0.137). In the chin implants group, the extraoral approach resulted in a lower dehiscence rate than the intraoral approach. Patients in the genioplasty group had significantly higher satisfaction scores than those in the chin implant group (P = 0.001). Overall, the rates of the complications assessed were lower and patient satisfaction was higher after osseous genioplasty when compared to chin augmentation with implants.

Chin Dysmorphology in the Primary Rhinoplasty Population: Prevalence, Objective Analysis, and Implications.

BACKGROUND: Chin flaws are far more common than recognized. Denial of genioplasty by parents or adult patients can present a surgical planning enigma, especially in patients with microgenia and chin deviation. This study aims to investigate the frequency of chin imperfections on patients seeking rhinoplasty, review the conundrum they generate, and offer management suggestions based on over 40 years of the senior author's experience. METHODS: This review included 108 consecutive patients presenting for primary rhinoplasty. Demographics, soft tissue cephalometrics, and surgical details were obtained. Exclusion criteria included prior orthognathic or isolated chin surgery, mandiblular trauma, or congenital craniofacial deformities. RESULTS: Of the 108 patients, 92 (85.2%) were female. Mean age was 30.8 years (SD±13, range 14-72). Ninety-seven (89.8%) patients exhibited some degree of objective chin dysmorphology. Fifteen (13.9%) had Class I deformities (macrogenia), 63 (58.3%) Class II (microgenia), and 14 (12.9%) Class III (combined macro and microgenia in the horizontal or vertical vectors). Forty-one (38%) patients had Class IV deformities (asymmetry). While all patients were offered the opportunity to correct chin flaws, only 11 (10.1%) underwent such procedures. Five (4.6%) patients had simultaneous osseous genioplasty (mean advancement 7.8mm, range 5-9mm); 7 (6.5%) received fat grafting to the chin (mean volume 4.4cc, range 1-9cc). CONCLUSIONS: A considerable proportion of primary rhinoplasty patients possess quantifiable chin dysmorphology on circumspect examination, high-resolution photographs and cephalometric analysis. Only a small number agree to surgical interventions that pursue full facial harmony. Potential reasons for these findings, patient aversion, and mitigation strategies will be discussed. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Nonsurgical Chin Augmentation Using Hyaluronic Acid: A Systematic Review of Technique, Satisfaction, and Complications.

The article titled "Nonsurgical Chin Augmentation Using Hyaluronic Acid: A Systematic Review of Technique, Satisfaction, and Complications" by Ou et al. in Aesthetic Plastic Surgery presents a systematic review focused on categorizing complications associated with hyaluronic acid (HA) dermal fillers. However, concerns arise regarding the methodologies employed in the reviewed studies. It is essential to have precise knowledge of the properties of the active substance for treatment standardization. Gaining a comprehensive understanding of the key characteristics of the HA used is paramount to determine if there is an association between these properties and the risk of complications.Understanding HA's rheological properties, including viscosity, elasticity, and cohesiveness, is crucial for selecting the most suitable facial filler. While we acknowledge the authors' contributions, we strongly believe that further analysis should incorporate these factors.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

[Three-dimensional comparative study on the stability of bimaxillary simultaneous genioplasty and simple genioplasty].

PURPOSE: To establish a three-dimensional method to evaluate whether there is a difference in stability between bimaxillary simultaneous genioplasty and simple genioplasty. METHODS: This study was a retrospective study. Sixty patients who underwent genioplasty were selected. They were divided into bimaxillary simultaneous genioplasty group (n=30) and simple genioplasty group (n=30). The spiral CT data of patients at 2 months before operation (T0), 7 days after operation (T1) and 12 months after operation (T2) were collected, reconstructed and separated, and the three-dimensional model of maxilla and mandible was obtained. A three-dimensional analysis method of stability was established by 3D-matching. Recurrences in three-dimensional space 12 months after surgery were analyzed in two groups of patients. Statistical analysis of the data was performed with SPSS 26.0 software package. RESULTS: In simple genioplasty, the maximum amount of the chin recurrence was sagittal backward recurrence (0.54±0.38) mm, and the sagittal recurrence rate was 12.27%. In bimaxillary simultaneous genioplasty, the maximum amount of the chin recurrence was sagittal backward recurrence (0.60±0.31) mm, and the sagittal recurrence rate was 12.96%. Rotation occurred in both groups 12 months after operation, which was 1.98±2.70° in the simple genioplasty group and 1.01±1.61° in the bimaxillary simultaneous genioplasty group(P＜0.05). There was no significant difference in the sagittal movement of the chin between the two groups, and in the sagittal recurrence(P＞0.05). CONCLUSIONS: The three-dimensional method established in this study can be used to evaluate the stability after genioplasty. The recurrence after genioplasty mainly occurred in the sagittal direction. The rotation trend of chin after genioplasty is worthy of attention. There was no increased risk for bimaxillary simultaneous genioplasty.

The prediction of sagittal chin point relapse following two-jaw surgery using machine learning.

The study aimed to identify critical factors associated with the surgical stability of pogonion (Pog) by applying machine learning (ML) to predict relapse following two-jaw orthognathic surgery (2 J-OGJ). The sample set comprised 227 patients (110 males and 117 females, 207 training and 20 test sets). Using lateral cephalograms taken at the initial evaluation (T0), pretreatment (T1), after (T2) 2 J-OGS, and post treatment (T3), 55 linear and angular skeletal and dental surgical movements (T2-T1) were measured. Six ML modes were utilized, including classification and regression trees (CART), conditional inference tree (CTREE), and random forest (RF). The training samples were classified into three groups; highly significant (HS) (≥ 4), significant (S) (≥ 2 and < 4), and insignificant (N), depending on Pog relapse. RF indicated that the most important variable that affected relapse rank prediction was ramus inclination (RI), CTREE and CART revealed that a clockwise rotation of more than 3.7 and 1.8 degrees of RI was a risk factor for HS and S groups, respectively. RF, CTREE, and CART were practical tools for predicting surgical stability. More than 1.8 degrees of CW rotation of the ramus during surgery would lead to significant Pog relapse.

Stability of box genioplasty: a retrospective study.

In box genioplasty it is possible to advance, retrude, impact, and elongate, as well as to correct asymmetry. The aim of this study was to analyse the stability of box genioplasty as part of orthognathic correction. Twenty-five consecutive patients who had gone through the multidisciplinary pathway were selected. Menton and pogonion positions on radiographs taken just prior to surgery, and actual surgical movement on three-week and 12-month postoperative cephalograms, were compared. A one-sample Wilcoxon test was applied to assess whether the distributional change in advancement and vertical measurements was equal to zero. After treatment, anteroposterior changes in pogonion and vertical changes in menton were statistically insignificant (p>0.05). Our study demonstrated statistically significant stability of menton and pogonion positions after box genioplasty when surgical movement was only in the symphysis.

Bone healing and stability after advancement genioplasty using a pre-bent absorbable plate and screws.

This study aimed to compare the bone healing and stability of the chin with a pre-bent absorbable plate and a manually bent absorbable plate after advancement genioplasty. Patients with class II malocclusion who underwent genioplasty with bimaxillary surgery were included. After genioplasty, two absorbable bicortical screws were fixed on both sides. Then, a pre-bent absorbable plate and screws were used in the center area to fix the segment in advancement genioplasty (PB group). A manually bent absorbable plate was used for the remaining patients (MB group). Computed tomography (CT) was performed before surgery and 1 week and 1 year after surgery. Changes in the pogonion (Pog) and menton (Me) points, soft tissue points, and the ratio of bone squares under the plate were evaluated using lateral cephalometric images reconstructed with 3-dimensional CT data. 32 patients were included in the study. There were no significant differences in the cephalometric measurements in the time interval from 1 week to 1 year. However, the bone square ratio in the PB group showed a significant increase after 1 year (P = 0.0021). Within the limitations of the study it seems that the use of a pre-bent absorbable plate is effective in promoting bone healing after advancement genioplasty.

Occlusal Plane Angle as a Key Factor for Chin Protrusion After Mandibular Osteotomy in Skeletal Class III.

There is no treatment algorithm to decide whether maxillomandibular or mandibular osteotomy alone should be performed in borderline cases. This study assessed the factors that affect the changes in soft tissue after mandibular setback. Patients who underwent mandibular osteotomy alone to correct mandibular protrusion were included in this study. Hard and soft tissue analyses were performed on lateral cephalograms before and 12±3 months after surgery. The popular points were set for referencing hard and soft tissues on the lateral cephalogram. Nasolabial, labiomental, and soft tissue facial plane angles were measured for the soft tissue assessment. To assess the mandibular setback amount, SNB was calculated. Twenty-one patients were included in this study. The nasolabial angle was increased after surgery and its change significantly correlated with the change in SNB ( P =0.00815). The change in soft tissue facial plane angle after surgery per change in SNB significantly correlated with the occlusal plane angle ( P =0.0009). An occlusal plane angle of at least 15.45 degrees was required for the SNB and soft tissue facial plane angle to change to the same degree. The occlusal plane angle (whether or not it was ≥15.45 degrees) may help in determining the surgical approach in borderline cases, specifically on whether maxillomandibular or mandibular osteotomy alone should be performed if the mandibular setback is simple.

The Versatile Role of Fat Injection During Various Genioplasties.

BACKGROUND: Fat injection has become increasingly popular in aesthetic surgery, but there is a sparsity of literature regarding its role during genioplasty. In this study, we present the largest series of patients receiving fat injections to the chin for various indications. METHODS: Data were collected from January 2016 to December 2021 for patients who underwent chin fat injection for a variety of chin refinements. Patients with chin fat injection were divided into isolated genioplasty with fat injection (CF), combined facial and chin fat injection (CFC) and combined chin fat injection and osseous genioplasty (CFG). Complication rates and reoperations were compared using Fischer's exact test between each cohort. RESULTS: 181 patients were included in final analysis, with 14 patients in CF cohort, 130 patients in CFC cohort, 24 patients in CFG cohort, and 13 patients who underwent genioplasty alone. Repeat fat injections were required in 17 (9.4%) patients overall, which included 14 patients (10.8%) of CFC subcohort and three patients (12.5%) of CFG subcohort (p > 0.05). No patients who underwent genioplasty alone or CF required reoperation. There were no significant differences in complications between genioplasty alone group (0%) in comparison to CF (7.1%; p = 1.00), CFC (6.2%; p = .53), or CFG cohorts (7.7%; p = 1.00). CONCLUSION: Fat injection can safely correct minor chin deficiency or asymmetry, as either an isolated procedure or in combination with osteotomies. Additionally, fat injection enables advancement of the caudal segment to achieve superior outcomes by preventing unaesthetic deepening of labiomental groove which will not be advanced during sliding osteotomy. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Gender Facial Affirmation Surgery; Techniques for Feminizing the Chin.

The shape and size of the chin are very important in feminizing the lower third of the face, and osseous genioplasty is commonly used in FFS. Different variations of the osseous genioplasty can be used to feminize the chin. The 1-piece genioplasty reduces the size and rounds the chin. 2-piece genioplasty reduces or increases the projection of the chin, but retains the same shape. 3-piece genioplasty also reduces or increases the projection, but has the additional benefit of narrowing the chin. This narrowing helps to create the "V" shaped lower face that is often desired by patients seeking facial feminization. Protection of the mental nerve and resuspension of the mentalis muscle is essential to prevent permanent lower lip numbness and ptosis respectively.

Effectiveness of Autogenous Chin Bone Graft in Reconstructive Surgery of Cleft Patients: A Systematic Review With Meta-Analysis and Algorithm of Treatment.

PURPOSE: Bone grafting is fundamental in the treatment of cleft patients, and several grafting materials have been used for this purpose. The objective of this study is to evaluate the effectiveness of autogenous bone graft from the chin in the reconstruction of cleft alveolus. METHODS: Searches were performed in six databases (PubMed, Scopus, Cochrane, LILACS, Embase, and Google Scholar) by two researchers individually until July 2022. This study was registered in the International Prospective Register of Systematic Reviews (CRD42021267954) and conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The predictor variable is reconstruction technique, grouped into three levels: autogenous genial grafts, other endochondral autogenous grafts, and bio- or tissue-engineered materials. The outcome variables were alveolar cleft healing rate and bone height. The secondary variables were complications that included infections, necrosis, paresthesia, and dehiscence. Data analysis included the risk of bias and assessment of the certainty of evidence by the risk of bias in nonrandomized studies of interventions and grading of recommendations, assessment, development, and evaluation tools, respectively. The meta-analysis was performed with heterogeneity based on random effects of I2 and 95% confidence. RESULTS: In the initial search, 4,833 articles were found, and 10 of them were included in this systematic review. The included studies were from six countries on three different continents, with a sample of 692 patients. It was observed that the chin bone graft (214 patients) when compared to the endochondral bone graft (386 patients) reduced by 0.42 [confidence interval 95% = 0.18, 0.95] times the prevalence of bone resorption (P = .040 and I2 = 70%) analyzed in radiographic images. Two studies evaluated the bone filling through computed tomography, and there was no statistically significant difference between the groups (P = .340, I2 = 0%). Only two studies had a low risk of bias. CONCLUSION: Based on a low certainty of evidence, the chin autogenous bone graft proved to be similar to the endochondral graft in the reconstruction of the cleft alveolar; however, the limited number of studies with high heterogeneity and an uncertain risk of bias decreased the strength of the results found in this systematic review. New controlled primary studies should be carried out with the purpose of safely determining the effectiveness of chin bone grafts for the reconstruction of cleft alveolar.

Soft Tissue Chondroma of the Chin.

Soft tissue chondromas are benign tumors, generally of the hands or feet, very rarely of the head and neck region. Repeated microtrauma may be as an initiating factor. The authors describe a case of a soft tissue chondroma of the chin in a 58-year-old male who had used a continuous positive airway pressure face mask for obstructive sleep apnea for 3 years. The patient presented with a hard mass on his chin for 1 year. Computed tomography imaging showed a heterogeneous enhancing mass, with calcification in the subcutaneous layer. Intraoperatively, the mass was beneath the mentalis muscle and abutted the mental nerve, without bone involvement. The diagnosis was a soft tissue chondroma. The patient recovered fully, without recurrence. The primary cause of soft tissue chondromas is unknown. The authors consider that continuous use of a continuous positive airway pressure face mask may play a role in the etiology.

Correcting the Broad, Flat and Short Chin Using Modified M-genioplasty.

BACKGROUND: Several genioplasty techniques can narrow the width of the chin. Nevertheless, patients with a broad and short chin who received these methods were unsatisfied with the outcomes. The goal of this study was to analyze the clinical outcomes of modified M-shaped genioplasty for broad, flat and short chin deformity. METHODS: Thirty-eight patients with broad, flat and short chins were included in this study from January 2019 to December 2021. The preoperative design was performed individually according to the data of the chin and the patient's desire of final chin shape. Narrowing and vertical elongating genioplasty was performed for all the patients with modified M-shaped genioplasty under general anesthesia according to the preoperative designs. All patients have completed the FACE-Q preoperatively and 3 months postoperatively. The results were evaluated by clinical appearances and FACE-Q scores. RESULTS: The vertical lengthening of the chin was 2-5 mm, with an average of 3.02 mm. The horizontal narrowing width was 3-6 mm, with an average of 5.6 mm. FACE-Q scores in satisfaction with the chin increased significantly from 35.34 ± 9.57 to 72.95 ± 6.81. There were no severe complications took place during the time frame of 3-24 months postoperatively. CONCLUSIONS: The modified M-shaped genioplasty preserved the bone structure in the midsymphyseal area and suprahyoid muscular attachments as far as possible, and the bone segments may be repositioned quickly. This technique produced reliable and esthetically satisfying results in correcting a short, flat and broad chin, with altered vertical length, slope, width and protrusion three-dimensionally. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effects of the Mandibular Functional Units and Soft Tissue on Facial Asymmetry.

Mandibular asymmetry has a variety of patterns because they are affected the position and the shape of mandible in addition to the overlying soft tissue. This study aimed to assess the factor in mandibular asymmetry, focusing on each mandibular functional units and the soft tissue thickness in the mandibular angle area. Forty patients who were diagnosed with facial asymmetry and undergone the orthognathic surgery without genioplasty were enrolled in this study. The skeletal patterns of the patients were analyzed by using cone-beam computed tomography data and 3D virtual images divided into 2 categories; the mandibular functional unit length and the soft tissue depth. All difference in bilateral mandibular functional unit lengths had a statistically significant with chin top deviation ( P <0.05). The greatest correlation was the condylar unit length compared with other functional units. The soft tissue thickness in the mandibular angle area was not statistically related to chin top deviation ( P >0.05), and the soft tissue did not change remarkably after orthognathic surgery ( P >0.05). This study suggests that the considerations of a surgical plan for treatment based on the mandibular asymmetry.

Reliability and Validity Evaluation of the Chin Augmentation With Medpor Using FACE-Q Scales Effectiveness.

BACKGROUND: Chin augmentation (CA) is important treatment modality for microgenia. The use of implantable alloplastic biomaterials in CA grows in popularity, and there is no verifiable documentation of patients' satisfaction about CA with Medpor (CAWM) exists in the literature, this study examined effectiveness of CAWM by analyzing patient satisfaction. METHODS: Patients had undergone CAWM were followed up postoperatively. Occurrence of complications was collected, patients' satisfactions with chin shape and surgical decision were analyzed using FACE-Q scales, the reliability of operation was studied through analyzing the statistics, and the influences of sex and follow-up time on satisfaction were compared. RESULTS: One hundred ten patients who had undergone CAWM received FACE-Q scales and 64 valid questionnaires were collected. 61 (95.3%) showed high satisfaction with chin shape after CAWM (Cronbach α coefficients were all above 0.8), the median values of satisfaction of chin shape and decision making were 85 (67, 100) and 100 (75,100), respectively. The median chin satisfactions of females and males were 87 (67, 100), 79 (61,100). The median chin satisfactions of patients had surgery before 2 years ago and within 2 years were 81 (67, 100), 87 (64,100), respectively. During the follow-up, among 110, 1 (0.91%) developed graft-related infection and 1 (0.91%) developed an allergic reaction, 1 (0.91%) underwent prosthesis removal because dissatisfaction with chin shape. CONCLUSIONS: Chin augmentation with prothesis is a safe and efficacious way to improve microgenia. Medpor is the desired implant material with less infection, displacement and bone absorption, which is worthy of promotion and further study in CA surgery.