Does the Implementation of Virtual Planning has a Significant Impact on Reducing the Revision Rate in Orthognathic Surgery?

PURPOSE: Conventional orthognathic surgical planning has limitations in accurately transferring the relationship between soft tissue and bone. Virtual planning offers enhanced accuracy and visualization through computer simulation. This study aimed to compare the need for reoperation between patients who underwent conventional and virtual surgical planning for orthognathic surgery. MATERIAL AND METHODS: The study included 352 patients who underwent orthognathic surgery. Reoperation rates and reasons for reoperation were evaluated in patients with conventional model surgery planning (143 patients) and virtual planning (209 patients). RESULTS: The reoperation rate was 7.69% for conventional surgery patients and 3.82% for virtual planning patients. Malocclusion was the most common reason for reoperation in both groups. Bilateral sagittal split ramus osteotomies (BSSO) and genioplasty were the most frequently performed revision procedures. CONCLUSION: Virtual planning in orthognathic surgery may lead to a reduced reoperation rate compared with conventional planning methods. The accuracy, visualization, and interdisciplinary collaboration offered by virtual planning can improve surgical outcomes.

Comparison of Different Genioplasty Techniques in Terms of Neurosensory Deficit and Haematoma Formation.

OBJECTIVE: To compare different types of genioplasty techniques (chin advancement, rotation and advancement, setback, and reduction) in terms of neurosensory deficit and haematoma formation. STUDY DESIGN: Comparative analytical study. Place and Duration of the Study: Department of Oral and Maxillofacial Surgery, Armed Forces Institute of Dentistry, Rawalpindi, Pakistan, from January 2022 to April 2023. METHODOLOGY: Patients requiring genioplasty and fulfilling the inclusion criteria i.e. both genders aged 16-60 years were included and divided into 4 groups according to the type of genioplasty performed. Genioplasty was planned as per the ortho treatment plan and performed under general anaesthesia. Setback genioplasty was performed on 8 patients, advancement genioplasty on 11 patients, reduction genioplasty on 3, and advancement with rotation genioplasty on 16 patients. Postoperatively neurosensory deficit was recorded on follow-up after 1 month by subjective and objective assessments, and haematoma formation was assessed clinically on the 7th day after the procedure. RESULTS: Advancement with rotation genioplasty showed the highest frequency of neurosensory deficit (almost 50%) and reduction type genioplasty showed the least frequency of neurosensory deficit (<1%, p = 0.49). The frequency of haematoma formation was maximum in the advancement with rotation genioplasty (62.5%) and minimum in equal setback genioplasty (25%, p = 0.61). CONCLUSION: Advancement with rotation genioplasty had the highest rate of postoperative neurosensory deficit and haematoma formation when compared with other techniques of genioplasty. KEY WORDS: Genioplasty, Neurosensory deficit, Haematoma, Advancement with rotation genioplasty, Setback genioplasty.

Hybrid Chin Advancement: Combining Fat and Sliced Cartilage Grafts for Chin Augmentation During Rhinoplasty.

BACKGROUND: Facial balance significantly impacts aesthetics, particularly in the middle and lower thirds. Patients with chin retrusion often benefit from sagittal plane chin advancement in rhinoplasty, enhancing surgical outcomes and satisfaction. OBJECTIVES: This article presents a method for analyzing chin deformities and discusses a hybrid treatment approach to harmonize facial features, complementing rhinoplasty. METHODS: The chin positions of patients treated by the senior author were assessed. A retrospective analysis included 49 patients with chin retrusion of 2.5-6 mm. Among them, 22 patients initially offered chin implants declined, leading to planned chin augmentation. Fat grafting was exclusively performed for 20 patients lacking sufficient cartilage. The "Hybrid Chin Advancement" technique involved supporting tissues beneath muscles with nasal septum cartilage and fat injections and tissues above muscles with fat injection alone. RESULTS: Pre- and postoperative Legan angle measurements and chin advancements were compared across three groups. While preoperative Legan angles were statistically similar, postoperative Legan angles and advancement changes were significantly higher in the implant group (p < 0.0001). Comparing hybrid chin advancement and fat grafting groups, postoperative Legan angles and advancement changes were significantly higher in the hybrid chin group (p < 0.0001). CONCLUSIONS: Fat grafting suffices for mild advancements (~ 2 mm), while the hybrid chin method is effective for moderate advancements (~ 4 mm). For advancements exceeding 6 mm, implants or osseous genioplasty are optimal. Our study's hybrid approach offers an easy, safe, and reliable method for achieving facial harmony in the lower two-thirds without compromising patient expectations. 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 .

Genioplasty - A Review.

Genioplasty, a key technique for dentofacial abnormalities, is essential for establishing facial harmony. This surgical procedure entails an osteotomy of the chin, which alters its three-dimensional location to restore overall face equilibrium. Modern genioplasty, which is frequently performed alone or in combination with rhinoplasty, facelifts, and orthognathic surgery, employs a variety of materials for chin augmentation, ranging from autologous to alloplastic. Recent improvements include porous graft materials such as high-density polyethylene. Despite the need for secure osteotomy segments, soft tissues around the mandible have a natural propensity to return to their original anatomical position. In the discipline of genioplasty, face esthetics and facial evaluation have been a prominent emphasis, with historical evidence emphasizing the relevance of the chin in harmony, balance, and character perception. Customized implants provide a single therapy for rare anatomical defects, generally with lower morbidity, making them critical for patients undergoing many procedures or suffering from syndromic disorders. Virtual surgical planning advances will continue to give dependable solutions for small and complex chin position issues. Modern surgeons will continue to combine history, anatomy, rigorous evaluation, excellent execution, and technological breakthroughs to achieve the best possible outcomes for their patients, raising their social standing.

Optimizing Esthetic Outcomes and Bone Stability: Chin Advancement Through Inverted V Osteotomy.

Traditional horizontal osteotomies for small and short chins often yield suboptimal results due to limited bone advancement, resulting in deep labiomental folds and heightened bone resorption risks. This study investigates the effectiveness of an innovative inverted V-shaped osteotomy technique in enhancing esthetic outcomes for patients with such chin concerns. Thirty-eight patients who underwent inverted V-shaped osteotomy for recessed chins between January 2018 and June 2022 were included. Excluding cases involving simultaneous mandibular contouring surgery, patients were followed up for a median duration of 1.2±0.5 years. Preoperation and postoperation soft tissue pogonion (Pg') and labiomental fold depth (LMF) changes were measured. IBM SPSS (version 27.0) was used for statistical analysis, with significance defined as P <0.05. Patient satisfaction was assessed using a visual analog scale. Successful advancement genioplasty was performed on all patients without any severe complications. The average change in soft tissue pogonion (Pg') measured 6.2 (1.9) mm, and the mean alteration in labiomental depth was 0.42 (0.4) mm. The procedure achieved a bone to soft tissue movement ratio of 1:0.96. Patient satisfaction was notably high, with a mean VAS score of 8.7. An inverted V-shaped osteotomy enables greater bone advancement for small and short chins, leading to improved esthetic outcomes and offering a mechanically advantageous condition for bone segments.

F-Chin/Feminizing the Chin: A Genioplasty Technique with Virtual Planning for Male-to-Female Transgender Patients.

The chin is an essential structure in facial harmony and an important gender marker. Advancing a receding chin is fundamental to improve the facial appearance, particularly in male-to-female transgender patients. However, in patients with microgenia and/or retrognathia, desiring a more feminine appearance, a chin advancement can result in a wider, square shape; an undesirable effect. Genioplasty is a versatile procedure used in facial feminization surgery that allows modifying the natural anatomy of the chin in all three spatial dimensions. The technique herein described proposes a simple genioplasty procedure for feminizing the chin (F-chin genioplasty) in transgender patients where anteroposterior advance is required. Virtual planning was used to establish the landmarks for an anteroposterior advancement with transverse reduction in the chin. A perpendicular line to the Frankfurt plane passing through the incisal edge of the upper central incisor was used to plan the anteroposterior movement, and two vertical lines on the outer wall of the nasal cavity  for the chin transverse measurement. The authors present three case reports with the F-chin genioplasty transgender technique with satisfactory results, ensuring a more feminine facial appearance.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 .

Accuracy of the CAD/CAM technique compared with the conventional technique used for stand-alone genioplasty.

The benefit of the computer-aided design and manufacturing (CAD/CAM) technique for stand-alone genioplasty remains uncertain and was evaluated in this study. Patients who underwent a conventional genioplasty (n = 20) or genioplasty with the CAD/CAM technique (n = 20), and for whom cephalometry and photogrammetry were performed before and 6 months after surgery, were included. Deviations from predictions of the soft tissue pogonion (Pg'), lip inferior point to aesthetic line (Li-Esth), facial convexity angle (FCA), mentolabial angle (MLA), and ratios of soft to hard tissue movements were calculated. No significant deviation was observed for Pg' in either the conventional group (3.85 ± 4.36 mm; 1.91 ± 1.11 mm) or CAD/CAM group (1.28 ± 1.16 mm; 2.81 ± 3.08 mm), for horizontal and vertical movements, respectively. However, for forward movement, deviation from the prediction of Pg´ in the CAD/CAM group was significantly lower than that in the conventional group (P = 0.015). Deviations of Li-Esth, MLA, and FCA did not differ significantly between the groups. No definite preference for the CAD/CAM technique could be established, because deviations from predictions were not significant in either of the technique groups and lay within the clinically acceptable range.

Validation of a fully automatic three-dimensional assessment of orthognathic surgery.

The aim of the present study was to propose and validate FAST3D: a fully automatic three-dimensional (3D) assessment of the surgical accuracy and the long-term skeletal stability of orthognathic surgery. To validate FAST3D, the agreement between FAST3D and a validated state-of-the-art semi-automatic method was calculated by intra-class correlation coefficients (ICC) at a 95 % confidence interval. A one-sided hypothesis test was performed to evaluate whether the absolute discrepancy between the measurements produced by the two methods was statistically significantly below a clinically relevant error margin of 0.5 mm. Ten subjects (six male, four female; mean age 24.4 years), class II and III, who underwent a combined three-piece Le Fort I osteotomy, bilateral sagittal split osteotomy and genioplasty, were included in the validation study. The agreement between the two methods was excellent for all measurements, ICC range (0.85-1.00), and fair for the rotational stability of the chin, ICC = 0.54. The absolute discrepancy for all measurements was statistically significantly lower than the clinical relevant error margin (p < 0.008). Within the limitations of the present validation study, FAST3D demonstrated to be reliable and may be adopted whenever appropriate in order to reduce the work load of the medical staff.

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.

What is the angular accuracy of regional voxel-based registration for segmental Le Fort I and genioplasty osteotomies?

Among the accuracy analysis techniques for orthognathic surgery, regional voxel-based registration (R-VBR) has robust data, but remains unvalidated for smaller jaw segments. The purpose of this study was to validate the angular accuracy of R-VBR for segmental Le Fort I (SLFI) and genioplasty osteotomies. Postoperative cone beam computed tomography (CBCT) of consecutive patients with three-piece SLFI or genioplasties was rotated to a known pitch/roll/yaw (P/R/Y). Using R-VBR, a copy of the raw CBCT was superimposed onto the rotated CBCT at four mutual regions of interest (ROI): anterior, right posterior, and left posterior maxilla, and chin. The P/R/Y of each was subtracted from those of the rotated CBCT to calculate the angular error. The predictor and outcome variables were ROI and absolute angular error, respectively. The accuracy threshold was 0.5°. Ten SLFI and 34 genioplasties were analyzed based on the sample size calculation. The one-sample t-test and Wilcoxon signed rank test were applied in the analysis. The mean absolute error was 0.20-0.54° for the maxillary segments (all P ≤ 0.01) and 0.83-2.51° for the genioplasty segments (all P < 0.001). R-VBR has variable angular accuracy for SLFI osteotomies and may be insufficient for genioplasty. The findings may allow the design and interpretation of studies on SLFI and genioplasty with greater rigor, thereby contributing to minimizing the discrepancy between planned and achieved outcomes.

Does Aesthetic Osseous Genioplasty Impact Upper Airway Volume?

BACKGROUND: Although maxillomandibular advancement is the treatment of choice for obstructive sleep apnea syndrome (OSAS) in the presence of underlying maxillomandibular complex hypoplasia, there is still a gap in the literature regarding the impact of genioplasty upon upper airway volume (UAV). OBJECTIVES: The aim of this study was to evaluate the impact of isolated osseous genioplasty upon UAV. METHODS: A retrospective analysis of all patients subjected to isolated osseous genioplasty between July 2015 and July 2022 was conducted. Cone-beam computed tomography was performed preoperatively and postoperatively to assess the chin and hyoid 3-dimensional (3D) spatial position and UAV changes after surgery. RESULTS: A total of 44 patients were included in the study. Regarding surgical movements of the chin, almost all patients received a sagittal movement (n = 42; 39 forward and 3 backward), while in 8 patients a vertical movement (5 upward and 3 downward) was applied, and in 6 patients the chin was centered. Statistically significant increases in total UAV (P = .014) and at the level of the oropharynx (P = .004) were observed. Specifically, chin centering, upward and forward movements enlarged the oropharynx volume (P = .006, .043 and .065, respectively). Chin advancement enlarged the hypopharynx volume (P = .032), as did upward movement of the hyoid bone (P < .001). CONCLUSIONS: Results of the study suggest that aesthetic osseous genioplasty impacts the UAV: each 3D spatial chin movement differently impacts the upper airway by enlarging or narrowing it. However, further studies addressing the apnea-hypopnea index are required to assess its effectiveness in treating OSAS.

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.

[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.

Plication of the Suprahyoid Muscles Concomitant with Genioplasty to Improve the Aesthetics of the Submandibular Region / Plicatura de los Músculos Suprahioideos Concomitante con Genioplastia para Mejorar la Estética de la Región Submandibular

In addition to functionally correcting skeletal facial deformities, orthognathic surgery also has a great impact on aesthetics and facial proportions. However, patients who have soft tissue changes, such as tissue flaccidity, may not achieve an ideal result, and require complementary surgical techniques that promote aesthetic refinement. The literature on less invasive techniques is limited, and therefore, this work aims to report a surgical technique performed concomitantly with genioplasty to refine the harmony of the submandibular region, in a simple and effective way. Patient with skeletal class II deformity, with lack of mandibular definition and submandibular flaccidity, underwent bimaxillary advancement orthognathic surgery with advancement genioplasty to correct chin retrusion. Due to limited results with bone repositioning alone, plication of the suprahyoid musculature was performed in association with the same approach used in the genioplasty. As a result, there was traction in the cervical region, with a consequent decrease in the submental-cervical angle and improvement in submandibular aesthetics. Furthermore, there was no need for extensive surgical intervention and no impairment of the functional results of the orthognathic surgery itself. Therefore, it can be concluded that plication of the suprahyoid musculat ure concomitantly with genioplasty is a technique that promotes aesthetic gains in the cervical region.

Además de corregir funcionalmente las deformidades faciales esqueléticas, la cirugía ortognática también tiene un gran impacto en la estética y las proporciones faciales. Sin embargo, los pacientes que tienen cambios en los tejidos blandos, como la flacidez, pueden no lograr un resultado ideal y requieren técnicas quirúrgicas complementarias que promuevan el refinamiento estético. La literatura sobre técnicas menos invasivas es limitada, por lo que este trabajo tiene como objetivo reportar una técnica quirúrgica realizada concomitantemente con la genioplastia para refinar la armonía de la región submandibular, de manera simple y efectiva. Se trató a un paciente con deformidad esquelética clase II, con falta de definición mandibular y flacidez submandibular, intervenida de cirugía ortognática de avance bimaxilar con genioplastia de avance para corregir la retrusión del mentón. Debido a los resultados limitados solo con el reposicionamiento óseo, se realizó la plicatura de la musculatura suprahioidea en asociación con el mismo abordaje utilizado en la genioplastia. Como resultado, hubo tracción en la región cervical, con la consiguiente disminución del ángulo submentoniano-cervical y mejoría en la estética submandibular. Además, no hubo necesidad de una intervención quirúrgica extensa ni deterioro de los resultados funcionales de la cirugía ortognática en sí. Por lo tanto, se puede concluir que la plicatura de la musculatura suprahioidea concomitantemente con la genioplastia es una técnica que promueve ganancias estéticas en la región cervical.

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.

Autoimmune diseases and orthognathic surgery: A case series of 12 patients.

Autoimmune diseases result from the immune system attacking native cells and tissues due to the recognition of "self" antigens as foreign antigens. This group of disorders is associated with an increased risk of complications after surgical interventions, as the immune system may cause tissue destruction. The study aimed to investigate the risk of surgical complications in patients with autoimmune diseases, who are at a higher risk of complications due to their condition. Among 886 patients who underwent orthognathic surgery, twelve types of autoimmune diseases with 22 patients were identified. For this case-series study, 12 patients were selected with a follow-up period of at least two years. The surgical procedures were executed by a single surgical team, which involved single or multi-piece Le Fort I osteotomy, Hunsuck/Epker modification of bilateral sagittal split osteotomy (BSSO), and/or genioplasty. The recorded outcome variables were postoperative adverse events, including respiratory or blood-related complications, wound infection, neurosensory disturbances, temporomandibular joint (TMJ) complications, and relapse. Only two patients recovered after surgery without any postoperative complications, whereas others had delayed recovery from neurosensory disturbance (5/12), infection (5/12), TMJ complications (2/12), and other complications. The findings of this study suggest that patients with autoimmune diseases undergoing orthognathic surgery are at higher risk of complications, highlighting the importance of careful consideration of patient selection and risk stratification before surgical intervention. The study also emphasizes the importance of close postoperative follow-up to detect and manage complications promptly.

Combined genioplasty, chondrolaryngoplasty, and glottoplasty: A novel scarless procedure in facial feminization surgery.

Facial feminization is a long process with multiple surgical steps that is known to improve quality of life in transgender patients. Visible scars are a frequent complaint by this community as it adds to the stigmatization in this population. Combined procedures have been shown to be effective, by reducing the number of hospitalizations and the total length of recovery periods. In this context, we propose a novel scarless procedure combining a chondrolaryngoplasty, a glottoplasty, and a genioplasty using solely a transoral approach. First, we perform a glottoplasty according to the technique described by Wendler et al. and then a contraction genioplasty. Finally, the thyroid cartilage is approached by a subplatysmal dissection, between the mandibular osteotomy fragments. For now, 15 patients have benefited from this procedure in our department. Preliminary results demonstrate that this is an easy and safe procedure with good esthetic results and good patient satisfaction.

Exploring the distribution of visual attention in genioplasty trainees using eye-tracking technology.

PURPOSE: This study aimed to investigate the visual attention of genioplasty trainees using eye-tracking technology, with the goal of providing insights for optimizing genioplasty training strategies. METHODS: Trainees were recruited for the study, and their visual attention distribution was monitored with an eye-tracking device while they watched a genioplasty procedure video. The percentage of fixation durations dedicated to areas of interest (surgical objects, instruments manipulated by the primary surgeon, and instruments controlled by assistants) were analyzed for each phase of the procedure. RESULTS: A total of 20 surgical trainees (8 males, 12 females; mean age, 27.8 years; range, 22-35 years) participated in the study. During the soft tissue reflection phase, trainees' percentage fixation durations on instruments controlled by the primary surgeon were higher than on surgical objects, but the difference was not significant (p > 0.05). The percentage fixation durations on instruments controlled by assistants were significantly lower than on those controlled by the primary surgeon or on surgical objects (p < 0.05). In the osteotomy, bone fixation, and suturing phases, the percentage fixation durations on surgical objects were highest, followed by instruments manipulated by the primary surgeon and those controlled by assistants, with significant differences (p < 0.05). CONCLUSION: Surgical trainees need to invest significant cognitive effort in focusing on the instruments manipulated by the primary surgeon and the surgical objects during the soft tissue reflection phase, as well as on surgical objects during the osteotomy, fixation, and suturing phases. Emphasizing these elements during instruction can help trainees reduce their cognitive load and effectively master genioplasty techniques.

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.