Osseous Genioplasty: Prevention of Witch's Chin Deformity with No-Degloving Technique.

BACKGROUND: Osseous genioplasty is a powerful procedure that can correct chin dysmorphology; however, traditional techniques may result in chin ptosis or a "witch's chin" deformity. Iatrogenic chin ptosis is thought to be caused by excessive degloving of soft tissue with a failure to reattach the mentalis muscle. In the authors' study, they compared the "no-degloving" technique (using a 90-degree plate with lag-screw fixation) to the "traditional" technique, for minimization of chin ptosis. METHODS: The authors compared genioplasty techniques for consecutive patients: group 1 (traditional) underwent degloving for fixation of a stair-step plate, whereas group 2 (no-degloving) underwent lag-screw fixation (n = 50; 25 patients per group). The authors compared operating room time, advancement, complications, preoperative-to-postoperative vertical height change of the pogonion and menton (obtained through cone beam computed tomographic scans), surgeons' assessment of witch's chin, and FACE-Q surveys. RESULTS: No-degloving versus traditional groups had similar age and sex distributions, horizontal/vertical change (5 mm/2 mm versus 6 mm/2 mm), length of surgery, and complication rate (5 percent). The traditional group had more deviation from expected position for both the pogonion (3.4 mm versus 1.2 mm; p ≤ 0.05) and menton (2.9 mm versus 0.8 mm; p ≤ 0.05), and more occurrences of witch's chin (six versus zero). No-degloving was superior for several FACE-Q scales, including Chin Appearance, Quality of Life, Satisfaction with Decision to Undergo Procedure, and Satisfaction with Outcome. CONCLUSION: No-degloving osseous genioplasty is a safe, reproducible technique that results in decreased soft-tissue ptosis and increased patient satisfaction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

A New Concept of Narrowing Genioplasty: Home Plate-Shaped Sliding Osteotomy.

BACKGROUND: Narrowing genioplasty is commonly performed among East Asian populations, as a broad and/or square chin can be aesthetically unappealing. This study was aimed to introduce the home plate-shaped sliding osteotomy technique for narrowing genioplasty and to evaluate the results of this technique. METHODS: A retrospective chart review of 117 patients who underwent home plate-shaped sliding osteotomy alone between 2011 and 2019 was performed. The angles of oblique osteotomy lines and measurements of caudal repositioning, which significantly affect the postoperative chin shape, were evaluated. RESULTS: The home plate-shaped sliding osteotomy technique was successfully accomplished for narrowing genioplasty as an isolated procedure. The mean distance of caudal repositioning was 3.9 ± 0.8 mm, and the mean angles of oblique osteotomy lines were 23.3 ± 4.8 degrees on the right and 21.8 ± 3.5 degrees on the left. This produced an aesthetically pleasing rounded and proportionately narrow chin. The incidence of minor complications was 6.0 percent. There were no major complications. In particular, the risk of inferior alveolar nerve injury was obviated, as an additional mandibular border osteotomy was not typically used with this technique. CONCLUSIONS: This new surgical procedure for narrowing genioplasty provides improved aesthetic results by altering the chin shape, rather than reducing the transverse width of the chin. The versatility of this procedure allows the chin shape to be adjusted with respect to narrowing, vertical lengthening, anterior advancement, and asymmetric or cleft chin correction. The present study suggests that home plate-shaped sliding genioplasty may be an excellent alternative for correcting broad and/or square chins and more complex chin deformities. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Orthognathic Hardware Complications in the Era of Patient-Specific Implants.

BACKGROUND: Patients undergoing orthognathic skeletal correction present with a variety of comorbidities that may affect surgical outcomes. The purpose of this study was to determine how patient risk factors and operative technique contribute to complication rates after orthognathic surgery in the era of patient-specific implants. METHODS: Retrospective cohort analysis was conducted of pediatric patients undergoing Le Fort I osteotomy, bilateral sagittal split osteotomy, and/or genioplasty from 2014 to 2018. Patient risk factors, operative characteristics, and postoperative outcomes were gathered and compared with appropriate statistics. RESULTS: Ninety-four patients met inclusion criteria, with an overall 1-year complication rate of 11.7 percent (11 of 94). Patient-specific mandibular plates are significantly associated with infection (p = 0.009; OR, 8.8), occurrence of any complication (p = 0.003; OR, 8.3), readmission (p < 0.001; OR, 11.1), and reoperation (p < 0.001; OR, 11.4). In patients with syndromes or history of cleft lip/palate, patient-specific mandibular plates are associated with infection (p = 0.006; OR, 10.3), readmission (p < 0.001; OR, 21.6), and reoperation (p < 0.001; OR, 22.9). In multivariate regression controlling for age, sex, syndrome status, and orofacial cleft history, use of patient-specific mandibular plates was associated with infection (p = 0.017; adjusted OR, 12.5), any complication (p = 0.007; adjusted OR, 11.8), readmission (p = 0.001; adjusted OR, 17.9), and reoperation (p = 0.001; adjusted OR, 18.9). CONCLUSIONS: In the era of patient-specific orthognathic surgery, syndromic status and use of patient-specific mandibular plates are associated with increased infection, readmission, and reoperation because of hardware-related complications. The authors' data support increased caution and counseling with use of patient-specific mandibular implants in patients with syndromic status, history of orofacial cleft, and history of previous maxillomandibular surgery given increased risk of hardware-related complications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

The Medial Subcoronoid Process Region as a Novel Source of Bone Grafts in Orthognathic Surgery and Genioplasty.

BACKGROUND: Since 2012, the authors have adopted the medial subcoronoid process bone interpositional grafting in OGS and genioplasty procedures. The purpose of this study was to present the technical details and clinical outcomes of this alternative bone interpositional grafting for LeFort I and chin osteotomies. METHODS: Consecutive patients (n = 50) who underwent single-splint bimaxillary OGS with or without genioplasty and received medial subcoronoid bone interpositional grafting were included. Standardized facial and intraoral photographs at early and late postoperative periods (12.2 ±â€Š3.3 and 44.8 ±â€Š8.4 months postsurgery, respectively) were blindly rated to assess facial symmetry, chin, and occlusion status based on qualitative rating scales. Complication and reoperation rates were also reviewed. RESULTS: The medial subcoronoid bone interpositional grafts were adopted to stabilize different LeFort I maxillary movement types or lengthening/advancing genioplasty (36 and 14 patients, respectively). Overall, the early facial symmetry, chin, and occlusion status were maintained at late evolutions. None of the patients had donor-site or bone graft-related complications (i.e., bad split, undesired mandible fracture, infection, fibrous union, nonunion, and/or permanent neurosensory deficit) or revisionary surgery during follow-up. CONCLUSION: The medial subcoronoid process bone grafting was a feasible alternative for bone interpositional defects of LeFort I and chin osteotomies with no significant morbidity and avoiding secondary donor sites.

A New Proposal for Three-Dimensional Positioning of the Chin Using a Single Computer-Aided Design/Computer-Aided Manufacturing Surgical Guide.

The workflow digital to aid the treatment of dentofacial deformities is a reality. Associated with the virtual planning, the creation of surgical guides assists the performance of osteotomies and bone positioning, increasing the accuracy of surgical outcomes. This study aims to present a new method of surgical guide for genioplasty based on the selected osteosynthesis plate.

Force and deformation stresses in customized and non-customized plates during simulation of advancement genioplasty.

PURPOSE: The aim of this study was to evaluate the distribution of deformation stresses in customized and non-customized plates during simulated advancement genioplasty, using the finite element method. METHODS: A customized plate (Traumec) was developed with 4.75 mm advancement, in ASTM F67 Grade 2 titanium, with four screws. Non-customized (standard) plates with 6 mm advancement (Stryker with six screws and Osteomed with four screws) were used for comparison. All the screws presented the same length (10 mm) and fixation system (2.0). The Traumec and Osteomed plates were fixed with two screws in the mandible, and another two in the segment, whereas the Stryker plate was fixed with three screws in the mandible, and another three in the segment. Six virtual models were generated in a computer-aided design program (Rhinoceros), in which the advancement and insertion of the plates were evaluated. All the plates were submitted to application of perpendicular and oblique forces of 5 N in the chin region. RESULTS: The Osteomed plate showed the highest stress value (1506 MPa), and the Traumec, the lowest stress value (560.20 MPa). The Stryker plate showed higher stress values for the segment screws than for the mandibular screws, unlike the other plates. CONCLUSIONS: The customized Traumec plate showed better deformation stress distribution and plate/segment stabilization when submitted to advancement genioplasty.

The Appropriate Retractors for Genioplasty.

Mental nerve (MN) injury is the most common complications of genioplasty; to protect the MN and oral mucosa, the authors invent and validate the appropriate retractors for genioplasty, and which can avoid the skin and mucous membrane of the lower lip, chin, and the vestibular gingiva of the mandibular incisor from paresthesia or dysesthesia. The patent application for the appropriate retractors for genioplasty is already submitted (Patent No 201610164563.3, China). The retractors provide a better surgical visual field and improve the operation efficiency while reducing the risk of surgery. And the method is simple, safe, efficient, and laborsaving.

Application of preoperative registration and automatic tracking technique for image-guided maxillofacial surgery.

OBJECTIVE: To investigate the practicality of preoperative registration technique in navigational surgery of facial skeleton. METHODS: Five cases were underwent navigational surgery with the preoperative registration technique. The accuracy of registration process was determined, and the deviation between planning model and postoperative computed tomography (CT) model was detected. RESULTS: In each case, the preoperative registration was successful for navigational surgery. Preoperative registration and automatic tracking enabled registration free in the operation procedure. The registration precision measured by the system was less than 0.8 mm. The deviation between the intraoperative anatomy and the CT image was less than 1.5 mm. CONCLUSIONS: Preoperative registration technique demonstrates the potential for improved workflow and accuracy in navigational surgery procedures. This technique was found to be particularly advantageous in cases of mandible navigational surgery in which the dynamic reference frame's hard to be fixed.

[Orthognathic surgery: surgical failures and complications]. / Chirurgie orthognathique : échecs chirurgicaux et complications∗.

Orthognathic surgery procedures mark the endpoint of lengthy orthodontic-surgical preparations and herald the completion of treatment for patients and their families. The main types of procedure are full maxillary Le Fort I osteotomies, mandibular osteotomies and chin surgery. To ensure a successful outcome, all require a favorable environment and extreme technical skill. But, like all surgical operations, they are also subject to peri- and post-operative complications resulting from treatment hazards or errors. Whatever the cause, surgical complications can entail failures in the management of the malformation. By seeking to understand and analyzing these complications, we can already help to prevent and reduce the contingent risks of failure.

A Simple and Reliable Method of Narrowing Genioplasty Using Biodegradable Screws.

The T-osteotomy technique is widely performed to improve lower face aesthetics. During this narrowing genioplasty procedure, metal fixtures are required to rigidly fix the bone segments. Specifically, the use of biodegradable osteofixations has become a viable surgical option as more patients now have the desire to surreptitiously undergo aesthetic surgery. The present report describes a narrowing genioplasty procedure with the use of biodegradable screws only. When the T-osteotomy technique was performed to narrow the chin, the bone segments were first temporarily fixed with a 4-hole titanium plate and screws. Later during the operation, the plate and screws were replaced with 4 biodegradable screws with bicortical fixation. Completion of bone healing can be confirmed by follow-up radiographs taken 6 months after the surgery. Despite increasing demand for the use of absorbable materials in aesthetic surgeries, biodegradable fixation systems have not been widely used for aesthetic surgeries due to a perception of high cost, inconvenient manipulation, prolonged operative time, and suspicions on long-term stability. Our novel method of using only biodegradable screws allows such limitations to be easily overcome by surgeons.

A Novel Method to Attain Highly Symmetric Oblique Mandibular Chin-Body Osteotomy.

UNLABELLED: Oblique mandibular chin-body osteotomy is a widely used narrowing genioplasty. However, the historic challenge is how to achieve a highly symmetric result of oblique mandibular chin-body osteotomy. Here, we present a novel and simple method to achieve a highly symmetrical mandibular chin-body osteotomy. METHOD: Ten consecutive patients underwent mandibular chinbody osteotomy used silicone triangle template technique. Patient and surgeon's satisfaction of the surgery and surgeon's confidence improvement with template during the surgery were measured. RESULT: All patients and surgeons were satisfied with the outcome. The operator's confidence was significantly improved during the operation. CONCLUSIONS: Silicone triangle template technique is an effective method to achieve highly symmetrical mandibular chin-body osteotomy and boost surgeon's confidence.

The Precise Repositioning Instrument for Genioplasty.

To improve the surgical precision of genioplasty, the authors develop and validate the precise repositioning instrument for genioplasty, which can guide the precise repositioning of chin bone segment truncated during genioplasty. The patent application for the precise repositioning instrument for genioplasty is already submitted (Patent No. 201410032051. 2, China). The accuracy of genioplasty can be improved significantly by using the precise repositioning instrument to locate the chin bone segment truncated. And this method is quick, simple, and safe.

Standardization of surgical techniques used in facial bone contouring.

Since the introduction of facial bone contouring surgery for cosmetic purposes, various surgical methods have been used to improve the aesthetics of facial contours. In general, by standardizing the surgical techniques, it is possible to decrease complication rates and achieve more predictable surgical outcomes, thereby increasing patient satisfaction. The technical strategies used by the author to standardize facial bone contouring procedures are introduced here. The author uses various pre-manufactured surgical tools and hardware for facial bone contouring. During a reduction malarplasty or genioplasty procedure, double-bladed reciprocating saws and pre-bent titanium plates customized for the zygomatic body, arch and chin are used. Various guarded oscillating saws are used for mandibular angloplasty. The use of double-bladed saws and pre-bent plates to perform reduction malarplasty reduces the chances of post-operative asymmetry or under- or overcorrection of the zygoma contours due to technical faults. Inferior alveolar nerve injury and post-operative jawline asymmetry or irregularity can be reduced by using a guarded saw during mandibular angloplasty. For genioplasty, final placement of the chin in accordance with preoperative quantitative analysis can be easily performed with pre-bent plates, and a double-bladed saw allows more procedural accuracy during osteotomies. Efforts by the surgeon to avoid unintentional faults are key to achieving satisfactory results and reducing the incidence of complications. The surgical techniques described in this study in conjunction with various in-house surgical tools and modified hardware can be used to standardize techniques to achieve aesthetically gratifying outcomes.

Functional genioplasty in growing patients.

OBJECTIVE: To evaluate the role of age as a moderator of bone regeneration patterns and symphysis remodeling after genioplasty. METHOD: Fifty-four patients who underwent genioplasty at the end of their orthodontic treatment were divided into three age groups: younger than 15 years at the time of surgery (group 1), 15 to 19 years (group 2), and 20 years or older (group 3). Twenty-three patients who did not accept genioplasty and had a follow-up radiograph 2 years after the end of their orthodontic treatment were used as a control group. Patients were evaluated at three time points: immediate preoperative (T1), immediate postoperative (T2,) and 2 years postsurgery (T3). RESULTS: The mean genial advancement at surgery was similar for the three age groups, but the extent of remodeling around the repositioned chin was greater in group 1, less in group 2, and still less in group 3. Symphysis thickness increased significantly during the 2-year postsurgery interval for the three groups, and this increase was significantly greater in group 1 than in group 3. Remodeling above and behind the repositioned chin also was greater in the younger patients. This was related to greater vertical growth of the dentoalveolar process in the younger patients. There was no evidence of a deleterious effect on mandibular growth. CONCLUSION: The outcomes of forward-upward genioplasty include increased symphysis thickness, bone apposition above B point, and remodeling at the inferior border. When indications for this type of genioplasty are recognized, early surgical correction (before age 15) produces a better outcome in terms of bone remodeling.

Validation of mandibular genioplasty using a stereolithographic surgical guide: in vitro comparison with a manual measurement method based on preoperative surgical simulation.

PURPOSE: Stereolithographic guidance, increasingly used in orthognathic surgery, has not been completely verified for genioplasty. This study compared the accuracy of manual measurement with that of a stereolithographic guide in vitro. MATERIALS AND METHODS: Thirty rapid prototype (RP) mandibular models (15 pairs) were included in the experimental (stereolithographic) and control (manual) groups (15 each). Surgical simulation was performed in the 2 groups by advancing the chin 5 mm and then vertically reducing the chin 5 mm using Mimics software. In the stereolithographic group, genioplasty was performed on mandibular RP models using a 3-dimensionally printed surgical guide based on surgical simulation results. In the control group, it was performed using an osteotomy line drawn according to simulation measurements. For the 2 groups, anterior horizontal transverse error and anterior and posterior vertical errors were compared, as were data from the osteotomized chin segment and the preoperative surgical simulation. Positional difference error was calculated and the differences were evaluated with t tests. RESULTS: For advancement genioplasty, the absolute anterior transverse error value was 0.47 ± 0.35 (mean ± standard deviation) with the stereolithographic guide, less than with the manual method (0.77 ± 0.45; P = .001). For reduction genioplasty, the absolute anterior vertical error value was 0.27 ± 0.23 mm with the stereolithographic guide versus 0.58 ± 0.49 mm with the manual method (P < .001). CONCLUSION: Use of a stereolithographic surgical guide increased accuracy, but the difference in mean error values between methods was only approximately 0.3 mm. The superior accuracy may not be compelling in favor of stereolithographic surgical guides.

Segmental stability in orthognathic surgery: hydroxyapatite/Poly-l-lactide osteoconductive composite versus titanium miniplate osteosyntheses.

Hydroxyapatite was included into F-u-HA/PLLA (unsintered hydroxyapatite - Poly l-lactide) composite osteosynthesis material for its documented osteoconductive capacity. This study investigates segmental retention capacities and outcome stability using F-u-HA/PLLA composite osteosyntheses in orthognathic surgery. Of fifty patients in total, 25 patients were osteofixated with F-u-HA/PLLA osteoconductive bioabsorbable osteosyntheses and compared to a group of 25 patients treated with titanium miniplates. The F-u-HA/PLLA group included 14 maxillary advancements, 4 setbacks, 13 impactions, 5 elongations at A-point; the titanium group included 20 maxillary advancements, 2 setbacks, 11 impactions and 11 elongations. In the mandible the F-u-HA/PLLA group included 13 advancements at B-point, 11 setbacks, 16 clockwise rotations and 8 counterclockwise rotations at the Gonial angle (Ar-Go-Gn); the titanium group included 9 mandibular advancements, 5 setbacks, 8 clockwise rotations and 6 counterclockwise rotations at Ar-Go-Gn. Segmental stability and relapse were assessed comparing preoperative, postoperative and follow-up roentgen cephalometrics at 22 ± 11 months on average in F-u-HA/PLLA cases, 24 ± 22 months on average in the titanium group. All absolute operative movements were nonsignificant in the F-u-HA/PLLA cases compared to the titanium osteosynthesis cases. Relapses were nonsignificant but there was greater vertical relapse in maxillary impactions with titanium osteosyntheses. Throughout this study, F-u-HA/PLLA composite osteosyntheses appeared as stable as titanium miniplates. It can therefore be concluded, although from a limited number of patients, that the investigated osteoconductive osteosynthesis can be used in a similar way to titanium miniplates in orthognathic surgery. Compared to earlier studies using other bioabsorbable polymers in the literature, F-u-HA/PLLA proved to be more stable in segmental retention.

The stability following advancement genioplasty with biodegradable screw fixation.

The purpose of this study was to compare postoperative stability using biodegradable screws with that of metal plates for fixation of advancement genioplasty. We studied patients who had advancement genioplasty alone or at the same time as other orthognathic surgery including mandibular setback. We assessed the lateral cephalographs at different time points (preoperatively, and 7 days, 3 months, 6 months, and 12 months postoperatively). A total of 54 patients were enrolled and 27 patients were assigned to each group. The position of pogonion was stable 12 months postoperatively, and the amount of skeletal advancement was reflected in soft tissue close to 100%. There were no clinical differences between biodegradable screws and conventional metal plates used for fixation. Biodegradable fixation for advancement genioplasty is a good option for patients who would require a second operation for removal of the plates.

Cost comparison of genioplasty: when indicated, wire osteosynthesis is more cost effective than plate and screw fixation.

PURPOSE: This retrospective study was conducted to determine the difference in the cost of genioplasty according to the osseous fixation technique used. PATIENTS AND METHODS: A retrospective study among orthognathic surgery patients treated over a 54-month period ending in June 30, 2011 was conducted. Immediately post surgery, panoramic and cephalometric radiographs of these patients were assessed to determine the presence of genioplasty procedure and the type of fixation used. The cost of the actual fixation used by the surgeons was compared with that which the cost would have been had the surgeons used the criteria described in the hypotheses, for plate and screws fixation when genioplasty is performed. RESULTS: A review of 1,498 orthognathic surgery patients revealed that 473 of these patients underwent genioplasty. Out of 473 patients, 425 had genioplasty to either advance and-or superiorly reposition the chin. Of these, 230 had wire osteosynthesis and 243 had some form of rigid fixation. The unit cost of fixation for genioplasty when wire osteosynthesis is used is less than C$5.00. The mean unit cost estimate in our patient group when pre-bent plates are used was C$542.00. All 230 patients in whom wire osteosynthesis was used demonstrated stable fixation of the bony parts and no immediate postsurgical adjustment was required in any patient. CONCLUSIONS: For patients requiring genioplasty to advance and-or superiorly reposition the chin, it is possible to use wire osteosynthesis to achieve accurate and stable fixation while reducing the fixation cost by more than C$500.00 per case. The surgeon should include cost considerations in the selection of treatment methods.