Reduction mandibuloplasty: ostectomy of the lateral cortex around the mandibular angle

Mandibular Angle Osteotomy via Intraoral Approach: A 15-Year Experience from a Single Plastic Surgery Center in China

BACKGROUND

Mandibular angle osteotomy (MAO) using an intraoral approach is a common procedure for correcting square facial contours in the Asian population. While previous retrospective studies have primarily focused on complications rates, limited research has examined time-related trends and the epidemiological characteristics of the surgical population. A comprehensive study with a large sample size and long-term follow-up is crucial to enhance outcomes, minimize complications, provide evidence-based insights, and consolidate clinical experience.

METHODS

This retrospective study reviewed 3,501 MAO cases performed via an intraoral approach between January 2008 and December 2022. Patients were categorized into three cohorts based on admission dates: group A (January 2008 to December 2012), group B (January 2013 to December 2017), and group C (January 2018 to December 2022). Demographic data, complication rates, and patient-reported satisfaction scores were analyzed across the groups.

RESULTS

The average ages for groups A, B, and C were 27.38 ± 6.94, 27.41 ± 6.42, and 28.57 ± 6.65 years, respectively, with group C patients being significantly older than those in group B (P < 0.001). Gender distribution showed 48 males and 825 females in group A; 93 males and 1,097 females in group B; and 122 males and 1,316 females in group C, with significant difference between groups A and B (P = 0.039). Complication rates were 13.05% (114 cases) in group A, 5.54% (66 cases) in group B, and 2.50% (36 cases) in group C. Postoperative satisfaction scores for groups A, B, and C were 3.32 ± 0.64, 3.86 ± 0.54, and 4.42 ± 0.58, respectively, with significant improvements across groups (P < 0.05).

CONCLUSIONS

The demand for MAO has steadily increased, particularly among individuals aged 21 to 40, with a predominance of female patients. Expanding indications have led to more cases involving middle-aged, elderly, and male patients. Advancements in surgical techniques have contributed to better aesthetic outcomes and lower complication rates. The use of modified osteotomy procedures and digital technologies has enabled safer, more precise surgeries across diverse populations, resulting in significant improvements in lower facial contours.

LEVEL OF EVIDENCE IV

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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.

Mandible Angle Resection with the Retroauricular Approach

Square-shaped and large moon-shaped faces are commonly observed in Asians, and the contour of the mandible is associated with the shape of the lower part of the face. Mandible contouring surgery is performed to create a softer impression for East Asians. Currently, most surgeries are performed using an intraoral approach. External approaches have not been cosmetically attempted because of possible damage to the facial nerve and visible scarring and have been limited to mandible bone fracture reduction. This study included 42 patients who underwent mandibular angle reduction via classical intraoral incision and retroauricular incision between April 2019 and October 2021. Clinical outcomes were assessed using the Global Aesthetic Improvement Scale and Visual Analog Scale. Surgery was successful in all cases, with no significant complications. An appropriate mandibular contour was achieved postoperatively. All patients were satisfied with the outcome. Some patients experienced short-term complications, such as hematoma and wound disruption of the skin above the incision line. However, these improved within 3 weeks, and no serious long-term complications were observed. Mandible angle resection with the retroauricular approach is a promising alternative for patients, allowing speedy recovery and the resumption of routine daily life.

Iliac crest towards alveolar processes or mandibular inferior margin in mandibular reconstruction with a vascularized iliac bone flap: which is better?

OBJECTIVE

The study aims to compare differences among iliac bone flaps with different iliac crest orientations for the repair of mandibular defects with an aim to analyze their advantages, disadvantages, and effects.

MATERIAL AND METHODS

Clinical data and computed tomography scans of all patients who underwent iliac bone flap repair of the mandible in Peking University School and Hospital of Stomatology from January 2016 to April 2021 were collected. Patients were divided into the iliac crest towards alveolar process (Group A) and the iliac crest towards mandibular inferior margin (Group B). Software was used to measure corresponding indicators. The results obtained for the groups were statistically analyzed.

RESULTS

The study included 78 patients (25 and 53 in groups A and B, respectively). The symmetry of the LC-type defect was better in group A (p < 0.05). The all-bone width of the alveolar process side in group A was greater than 6 mm; in 15 cases of group B, the width was less than 6 mm (p < 0.05). The intermaxillary distance of two sites were higher in group B (p < 0.05). The bone cortical thickness was significantly thicker in group A (p < 0.05).

CONCLUSION

One year after the mandibular body defect was reconstructed with a vascularized iliac bone flap, the iliac crest towards alveolar process group showed better bone symmetry, width, intermaxillary distance, and cortical thickness to meet the planting requirements.

CLINICAL RELEVANCE

The use of an iliac crest towards alveolar process may be a better approach for mandible reconstruction.

The Accuracy of a Patient-Specific Three-Dimensional Digital Ostectomy Template for Mandibular Angle Ostectomy

BACKGROUND

Although three-dimensional (3D)-printed digital ostectomy templates (DOTs) can help surgeons perform mandibular angle ostectomy (MAO) more precisely and safely, the clinical application of such templates is problematic.

OBJECTIVES

The aim of this study was to evaluate the accuracy of a novel DOT and improve the precision of MAO.

METHODS

A total of 20 patients with a prominent mandibular angle (PMA) were allocated into 2 groups (10 patients per group). A conventional DOT and a novel DOT were applied to guide MAO in Groups A and B, respectively. The mean time taken for curved osteotomy and the volume of postoperative drainage on 1 side within 24 hours were recorded. The deviations between the simulated and postoperative lower border of the mandible were measured on both sides.

RESULTS

All the patients were satisfied with the cosmetic outcomes. Statistical results showed that the mean time taken for curved osteotomy was shorter in Group B than in Group A, and that the volume of postoperative drainage on 1 side within 24 hours was similar between the 2 groups. The deviations at the anterior and posterior parts of the inferior border showed that the accuracy of osteotomy was higher in Group B than in Group A, and that there was no significant difference between the 2 groups in the middle part.

CONCLUSIONS

The novel DOT is easy to locate and fix tightly, which reduced the operating time and increased the safety and precision of the procedures.

LEVEL OF EVIDENCE: 4

Application of Segmented Template in Three-Dimensionally Guided Mandibular Angle Osteotomy

BACKGROUND

The procedure of mandibular angle osteotomy (MAO) via an intraoral approach is challenging and experience-dependent due to the limited field of view and inadequate operational space. Uncertainty about the osteotomy line and plane can lead to severe complications. A three-dimensional printed guidance template based on a computer-assisted preoperative simulation is a potential solution to this problem. The current study aims to retrospectively investigate the feasibility and accuracy of using a custom-made segmented template to guide the osteotomy plane during the procedure.

METHODS

Sixty patients who had segmented template-guided MAO were included in the study. Preoperative simulation using the custom-designed template and postoperative computed tomography were collected and parameters, including mandibular angle, gonion distance, and the mandibular plane angle were measured. A paired t tests and intraclass correlation coefficients (ICCs) were used to evaluate the efficacy, accuracy, and symmetry of the results. All complications were reviewed.

RESULTS

The patients had a significantly larger mandibular angle and narrower gonion distance postoperatively. Preoperative simulations and postoperative outcomes were compared; ICCs were larger than 95% indicating significant agreement. Bilateral postoperative comparisons of the mandible also demonstrated excellent agreement (ICC > 95%). Numbness in the chin area was the most frequent complication but all recovered by 3 months postoperatively.

CONCLUSIONS

The custom-made template can guide the osteotomy plane during the MAO procedure and achieve favorable accuracy and symmetry. Direct contact of the saw with the guidance template not only facilitates control of the osteotomy line but also the oblique angle of the osteotomy plane. This methodology may be a feasible and effective tool for mandibular contouring.

Sagittal split ramus osteotomy, intraoral vertical ramus osteotomy, and lateral corticectomy for asymmetric mandibular prognathism

Objectives

The purpose of this study was to evaluate the postoperative anteroposterior stability and improvements in facial asymmetry after performing LeFort I osteotomy in the maxilla, sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) in the mandible, and lateral corticectomy on the IVRO side.

Materials and Methods

From July 2009 to October 2018, a retrospective analysis was performed on 11 subjects. Lateral cephalometric radiograph was performed preoperatively (T0), postoperatively (T1), and at 12 months of follow-up (T2), and the B point distance was measured. Posteroanterior cephalometric radiograph was performed preoperatively (S0) and at 12 months of follow-up (S1) and was used to measure five indicators (Ag angle, M-Ag, Co-Ag, Co-Me, and Ag-Me) of facial asymmetry.

Results

The B point distances for T0 and T1 were significantly different (P=0.007), whereas those for T1 and T2 were not significantly different (P=0.1). In addition, there was a significant difference between the B point distances of T2 and T0 (P=0.026). Comparison of the facial asymmetry indicators before and after surgery showed a significant difference for all indicators between S0 and S1 the P-values of Ag angle, M-Ag, Co-Ag, Co-Me, and Ag-Me were 0.003, 0.003, 0.008, 0.006, and 0.004, respectively. The Z value was based on negative ranks.

Conclusion

There was no significant difference in the B point distances from postoperation to the 12-month follow-up. However, there were significant differences in all five indicators related to facial asymmetry before and after surgery. The values for the five indicators of facial asymmetry all increased postoperatively.

Contouring the Mandible for Aesthetic Enhancement in Asian Patients

A prominent mandible that gives a squared face in Asians is considered unattractive as it imparts a coarse and masculine image. Mandibular contouring surgery allows slender oval faces. The purpose of conventional mandible reduction is to make the lower face appear slim in frontal view and to have a smooth contour in lateral view. As shaping the lateral contour of the mandible alone may result in minimal improvement in the frontal view, surgical techniques to reduce the width of the lower face through narrowing genioplasty (i.e., the "V-line" surgery) and sagittal resection of the lateral cortex should be combined. Examination of the shape and symmetry, the relationship between the maxilla and the mandible, understanding overlying soft tissue contribution, and understanding the overall balance of the face are mandatory. An important factor influencing ideal facial shape is patient's personal preference, which is often influenced by his/her ethnic and cultural background. Especially when consulting patients of different nationalities or ethnic backgrounds, careful attention should be paid to the patient's aesthetic sensibility regarding the ideal or desirable facial shape. Narrowing the chin and modification of chin shape can be accomplished by narrowing genioplasty with central strip resection. This midsymphyseal sectioning procedure yields safe and very satisfactory results. This procedure not only augments the narrowing effect by leaving soft tissues attached to the bone but also enables modification of chin shape by altering the shape of resection. The surgeon should customize the surgery based on a comprehensive assessment of the patient's preoperative chin and mandible morphology complemented by an assessment of their aesthetic goals.

Repairing Cranial Defect With Autogenous Mandibular Outer Plate

BACKGROUND

Autogenous bone is the best material in cranioplasty because of biological advantages. Previously, skull, rib, ilium, and fibula have been used in the reconstruction of cranial defects. However, the application of autologous mandibular outer plate in the treatment of skull defect is rarely reported. This study evaluated the application of the autogenous mandibular outer plate in the reconstruction of cranial defect.

METHODS

Eleven patients who underwent cranioplasty with mandibular outer plate were recruited. Three-dimensional tomography data were collected to calculate the preoperative, immediate postoperative, and long-term follow-up volume of the bone graft area and donor bone site, and then the absorption rate and the regeneration rate of autogenous bone were analyzed.

RESULTS

The majority of the patients were satisfied with the reconstructive outcome. There are statistical differences in the volumetric measurements of the bone graft area and bone donor site at different time periods (P<0.05). The mean absorptivity of mandibular outer plate implanted in the cranial defect area was (17.30 ± 5.03)% after 3 to 24 months postoperatively, the average regeneration rate of mandibular outer plate volume was (41.65 ± 9.85)% at the same period.

CONCLUSION

This report shows that the cranioplasty with mandibular outer plate bone graft may be an optional surgical procedure.

Reducing Prominent Mandibular Angle Osteotomy Complications: 10-Year Retrospective Review

BACKGROUND

Several methods are available for mandibular reduction, and each method is characterized by unique limitations and complications. However, only a few studies have systematically analyzed these complications. This study aimed to investigate the effects of the outcome of performing curved mandibular angle ostectomy and outer cortex grinding in 1-stage operation and to examine the causes of different types and characteristics of complications.

METHODS

The subjects consisted of 528 patients who were subjected to curved mandibular angle ostectomy and outer cortex grinding in 1-stage operation through an intraoral approach. Surgical complications and related factors were recorded, and the rates of complication according to surgeons were simultaneously evaluated.

RESULTS

The esthetic appearance of all of the patients was significantly improved, and they were satisfied with the results of the operation. The complication rate was 5.87%. No serious complications, such as subcondylar fracture, massive bleeding, permanent facial nerve, or asymmetry, occurred. Some complications, including 4 cases of hematoma, 4 cases of severe swelling, 2 cases of infection, and 1 case of sagging face, were detected. The absolute complication rate among faculty members ranged from 3.5% to 11.1%.

CONCLUSIONS

Our protocol is an effective method for mandibular angle osteotomy with very few complications. The rate of complications can be effectively reduced, and some serious complications can be avoided because protective measures are improved.

Three-Dimension-Printed Surgical Guide for Accurate and Safe Mandibuloplasty in Patients With Prominent Mandibular Angles

Performance of mandibuloplasty is highly dependent on each surgeon's experience, and reproducing the results of simulation surgery is often difficult. In order to obtain successful clinical outcomes, a fast and efficient surgery technique that minimizes operation time and risk to patients is needed. The authors designed a 3D-printed mandible fit surgical guide for use as a bridge between simulation and actual surgery.The authors enrolled 7 patients with prominent mandibular angle who visited the outpatient clinic of the Department of Plastic and Reconstructive Surgery at Asan Medical Center in Seoul, Korea between December 2013 and May 2017.The surgical guides were made with a 3D printer and simulated based on individual facial bone CT scans. The surgical guides were designed to fit the lower border of the mandible and to cover the portion planned for removal.The resulting personalized 3D-printed surgical guides were applied on both mandibular angles to the body and along the lower border of the mandible. Osteotomy of the mandibular angle and body were performed along the surgical guide. All patients recovered without any immediate postoperative complications. The use of 3D-printed surgical guide was effective in simplifying the process of mandibuloplasty.Our results demonstrate the value of 3D printing technology in mandibuloplasty.

One-Piece Mandibuloplasty Compared to Conventional Mandibuloplasty With Narrowing Genioplasty

BACKGROUND

Recently, the mandibular body and chin shape are known to be important issue as well as the mandibular angle. The authors have performed the one-piece mandibuloplasty from the mandibular angle to the most anterior part of chin to achieve the change of the whole mandibular shape as a one-piece.

METHODS

All of 14 patients who complaint prominent mandibular angle and chin were randomly allocated into 2 groups. Group I (n = 7) was treated with conventional mandibuloplasty with narrowing genioplasty and Group II (n = 7) was treated with one-piece mandibuloplasty. Pre- and postoperative clinical photography, cephalometry, computed tomography scan, 3-dimensional photography were taken and occurrence of secondary angle, patient's satisfaction, and operative time were evaluated.

RESULTS

The mean volume reduction per side was 41.8 cc on one-piece mandibuloplasty and 36.5 cc on conventional mandibuloplasty with narrowing genioplasty. Furthermore, average lower facial decreased from 64.3 to 61.0 after 6 months postoperatively and was maintained until 3 years on average after the operation. In one-piece mandibuloplasty group shows a little higher satisfaction about mandible body, and it was estimated that the presence of secondary angle makes dissatisfaction. The authors' treatment approach resulted in a shorter total surgery time than conventional technique (70.57 versus 105.14 min, P = 0.002).

CONCLUSIONS

One-piece mandibuloplasty based on 3-dimensional printing model turned out to be very successful for the natural shaping of the lower jaw in the patients with the prominent mandible in terms of the technical efficiency and the aesthetic point of view.

Transoral vertical ramus osteotomy fixed with Kirschner pins

Transoral vertical ramus osteotomy (VRO) has been condemned because the condyle has the potential to sag, and because it needs lengthy maxillomandibular fixation. We have therefore introduced a simple method of fixation, and examined its effectiveness and complications. After the osteotomy, the proximal and distal segments are trimmed to adapt to each other. Four Kirschner (K) pins 0.9mm in diameter are inserted percutaneously from the proximal to the distal segment while the condyle is positioned in the glenoid fossa. This is followed by a brief period of maxillomandibular fixation. We have reviewed the records of 95 patients who had unilateral or bilateral vertical ramus osteotomy fixed with K pins, after which the mean (SD) period of fixation was 19 (11) days. Fixation failed in two patients because excursion of the jaw was either too heavy or too early. The fixations were redone. All other fixations remained stable, including the 20 dual-jaw procedures in which VRO preceded maxillary osteotomy. The mean (SD) maximal mouth opening at final follow-up was 44 (7) mm, and in only one patient was it less than 30mm. Numbness of the lip or chin developed in seven patients, five of whom had other anterior mandibular procedures. Four patients had discomfort on palpation of the site of the pins, and one required removal. The new method was effective, and resulted in few complications within its limitations.

Robot-Assisted Surgery for Mandibular Angle Split Osteotomy Using Augmented Reality: Preliminary Results on Clinical Animal Experiment

Mandibular angle split osteotomy (MASO) is a procedure widely used for prominent mandibular angles. However, conventional mandibular plastic surgery is invasive and high risk. It may induce postoperative neurosensory disturbance of the inferior alveolar nerve, fractures and infection due to the complexity of the anatomical structure and the narrow surgical field of view. The success rate of MASO surgery usually depends on the clinical experience and skills of the surgeon. To evaluate the performance of inexperienced plastic surgeons conducting this surgery, a self-developed and constructed robot system based on augmented reality is used. This robot system provides for sufficient accuracy and safety within the clinical environment. To evaluate the accuracy and safety of MASO surgery, an animal study using this robot was performed in the clinical room, and the results were then evaluated. Four osteotomy planes were successfully performed on two dogs; that is, twenty tunnels (each dog drilled on bilaterally) were drilled in the dogs' mandible bones. Errors at entrance and target points were 1.04 ± 0.19 and 1.22 ± 0.24 mm, respectively. The angular error between the planned and drilled tunnels was 6.69° ± 1.05°. None of the dogs experienced severe complications. Therefore, this technique can be regarded as a useful approach for training inexperienced plastic surgeons on the various aspects of plastic surgery.

NO LEVEL ASSIGNED

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 .

New method for an evaluation of the esthetical improvements resulting from a mandibular angle reduction

Objectives

This paper proposes Han's ratio as an objective and quantitative comparative result obtained from pre and postoperative data in patients with a mandibular angle reduction.

Materials and Methods

Thirty patients, 12 men and 18 women, who visited the Department of Oral and Maxillofacial Surgery with the chief complaints of skeletal mandibular prognathism and prominent mandibular angle were selected. The subjects were classified into 3 groups according to the types of surgical procedures involved. Group A consisted of patients who underwent mandibular angle resection and mandibular setback. Group B was comprised of patients with mandibular angle resection, mandibular setback and genioplasty. Group C consisted of patients with mandibular angle resection, mandibular setback, Le Fort I osteotomy, and genioplasty. The landmarks placed in pre and postoperative frontal photographs were used to obtain the Han's ratio in each group. The Han's ratios were compared pre- and postoperation and according to the surgical techniques applied.

Results

Of the 3 groups who had undergone a mandibular angle resection, all showed a statistically significant increase in Han's ratio. On the other hand, there was no statistically significant difference based on the surgical techniques used.

Conclusion

The ratio of the lateral lower face proposed in this study is a potential indicator of postoperative esthetic enhancement in mandibular angle reduction surgery.

Occlusion-Fit V-Line Guide and Gooseneck Saw for Safe and Accurate Mandibuloplasty in Asians

BACKGROUND

A slender or slim face with narrow facial features is considered esthetically appealing in Asian people. Plastic surgery to obtain an oval face, called a 'V-line,' is popular among young people.

MATERIALS AND METHODS

A total of 20 Korean patients were included in this study. The patients underwent mandibular anguloplasty with three-dimensional computer-aided design and manufacturing surgical guides that were accurately fitted to the upper and lower teeth, allowing for precise replication of a virtual surgery during a real surgical procedure.

RESULTS

There were no significant complications, including severe bleeding, facial nerve injury, or airway obstruction. All patients were satisfied with the esthetic and functional results, except for one who was neutral toward the result. The mean satisfaction score was 4.75, which was between 'satisfied' and 'very satisfied.'

CONCLUSION

The V-line guide and gooseneck saw allowed for safe and fast resection of bone in the mandibular angle area. This technique provides consistent results during surgery as well as minimizing surgical complications.

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 http://www.springer.com/00266 .

A modified intraoral and extraoral approach osteotomy for the prominent mandibular angle

BACKGROUND

A prominent mandibular angle (PMA) is a relatively common condition in Asians, and surgeons typically use the intraoral approach to treat it. However, the approach can have many drawbacks due to the limited operative field and view. The procedures of osteotomy are not easily manipulated, and an exact resection is difficult. In addition, some major complications can easily occur. This article presents a modified osteotomy method for the PMA that avoids these disadvantages and makes the procedure easier to execute.

METHODS

Four modifications of the procedures have been made: 1. The addition of a small extraoral incision in the auriculocephalic sulcus behind the earlobe; 2. A modest reduction in both the intraoral incision length and excessive mouth traction; 3. The use of a reciprocating saw through the extraoral incision tunnel to simplify the operative procedure; and 4. Extraction of sustained-suction drains from the extraoral incision. Postoperatively, all patients were followed up and administered the validated satisfaction questionnaire and the Patient Scar Assessment Questionnaire.

RESULTS

From June 2010 to June 2015, 46 patients with a PMA underwent surgery using this method. All patients were satisfied with the esthetic results. The majority of patients could not feel an objectionable jaw line or bony step (86.9%), visible deformity (97.8%) or bony regrowth (95.6%). All patients noted a positive psychosocial influence. All patients perceived the overall appearance of their extraoral scar to be "good" or "excellent." Forty-five (97.8%) were "not at all" self-conscious of their scar. The overall complication rate was 6.5%, and no major complication was seen.

CONCLUSION

The described method for the surgical treatment of PMA is a simple and safe procedure with fewer complications. The procedure is easy to perform, consumes less time, and can help resect the PMA accurately and easily.

A safe and accurate method to perform esthetic mandibular contouring surgery for Far Eastern Asians

A tapered mandibular contour is popular with Far Eastern Asians. This study describes a safe and accurate method of using preoperative virtual surgical planning (VSP) and an intraoperative ostectomy guide to maximize the esthetic outcomes of mandibular symmetry and tapering while mitigating injury to the inferior alveolar nerve (IAN). Twelve subjects with chief complaints of a wide and square lower face underwent this protocol from January to June 2015. VSP was used to confirm symmetry and preserve the IAN while maximizing the surgeon's ability to taper the lower face via mandibular inferior border ostectomy. The accuracy of this method was confirmed by superimposition of the perioperative computed tomography scans in all subjects. No subjects complained of prolonged paresthesia after 3 months. A safe and accurate protocol for achieving an esthetic lower face in indicated Far Eastern individuals is described.

Quantitative Mandibular Angle Ostectomy Facilitated by Oscillating-Blade Saw With Scalable Guide

BACKGROUND

Although various techniques of mandibular angle ostectomy have been devised to correct overly prominent bony contours, none have incorporated methods to delineate the surgical line with precision. Herein, the authors describe one means of marking an ostectomy line more easily, using a specially designed oscillating-blade saw.

METHODS

Between July 2013 and June 2014, a total of 75 patients underwent quantitative mandibular angle ostectomy using a custom oscillating-blade saw equipped with a scalable guide. Corticectomy, also done routinely to improve frontal appearance, called for a reciprocating saw only. Aesthetic outcomes gauged subjectively by the questionnaire about satisfaction and symmetry after postoperative 6 months.

RESULTS

Satisfaction score was 4.9 and symmetric score was 4.7. No major complications, such as persistent nerve injury or fracture, were encountered.

CONCLUSIONS

Use of an oscillating-blade saw equipped with a scalable guide facilitated quantitative mandibular angle ostectomy, enabling precise, and reproducible surgery with satisfactory outcomes with less complications.

Endoscopic-Assisted Intraoral Three-Dimensional Reduction Mandibuloplasty

BACKGROUND

Oriental people have a square face with a prominent mandibular angle, which means masculine and coarse and is considered to be an unappealing feature. Reduction mandibuloplasty has become popular in the orient in the past 2 decades, and the operation was frequently performed through the intraoral approach. But an invisible mandibular angle forces the surgeon to perform blind ostectomy which leads to difficulty in performing an accurate ostectomy as planned, leaving unnatural mandibular contours and severe complications.

METHODS

From January 2010 to January 2013, a total of 112 patients with prominent mandibular angles underwent one-stage long-curved ostectomy combined with splitting corticectomy through an intraoral approach with endoscopic assistance for reduction of the lower face. A retractor with an adjustable endoscope provides a clear operative field; the ostectomy line was marked. The one-stage long-curved ostectomy and corticectomy were performed following the marked ostectomy line using an oscillating saw with angles of various degrees and length under direct vision.

RESULTS

Mandibular contouring was 3-dimensionally refined; the width of the lower face was reduced in the frontal view and the mandibular angle appeared natural and inconspicuous in the lateral view. The majority of patients were satisfied with both their frontal and lateral appearances. The gonial angle and the mandibular plane angle were increased effectively. No major complications such as fracture or facial nerve injury occurred.

CONCLUSIONS

Intraoral approach of long-curved ostectomy combined with splitting corticectomy with endoscopic assistance allows surgeons to perform accurate, safe, and reproducible ostectomies and to recontour mandible 3-dimensionally, which can make the face look thinner from the frontal view and, in the lateral view, keeps it more natural looking with smooth ostectomized borders.

Postauricular Approach for Mandibular Angle Ostectomy: An Alternative for Shortening the Recovery Time

Many surgical procedures to improve mandibular contour have been introduced in East Asia. Despite consensus regarding mandible contouring surgery, surgery which includes angle ostectomy and lateral cortex excision, some patients require only mandibular angle ostectomy. The intraoral approach is a widely used method, but has disadvantages with regard to the need for endotracheal intubation and patients are limited in their food intake for a considerable length of time. The authors wanted to shorten the recovery period and so the postauricular approach is introduced in this study and assessed.One hundred seventy-five Asian patients underwent mandibular angle ostectomy via a postauricular approach. All operations were performed under intravenous sedation without endotracheal intubation. Superficial subcutaneous dissection and vertical dissection were performed, with special care taken to avoid injuring the facial nerve. Patients responded to a simple questionnaire during the postoperative period. Questions solicited the patient's reason for their choice of this approach and their satisfaction with it.No visible scar and no palpable bony step were observed without ear pulling. Some patients experienced temporary sensory changes in the postauricular area. None of the patients complained of perioral numbness or facial paralysis. Six patients had significant bleeding in the operative field and 1 patient experienced salivary leakage for 2 weeks which was managed well without event. Of the 175 patients, 133 responded to the questionnaire. Satisfaction was expressed by 94.7% of patients and 88.7% of patients would recommend this surgery to their friends; 69.2% of patients experienced inconvenience for 1 week or less.The postauricular approach for mandibular angle ostectomy is a very convenient method for surgeons to use for patients who want to undergo mandibular angle ostectomy with a short recovery time.

3D-CT evaluation of mandibular morphology after mandibular outer cortex osteotomy in young miniature pigs: the role of the periosteum

AIM

The purpose of this study was to evaluate the role of periosteum on the healing and growth of mandible after mandibular outer cortex osteotomy using three-dimensional computed tomography.

METHODS

Eighteen 3-month-old miniature pigs were randomized into three groups. The mandibular outer cortex osteotomy was performed on both sides in group I, and on the left side in group II. In groups I and II, the local periosteum on the left side was resected. In group III, no operation was performed. The evaluation of mandibular morphology of all the animals was performed based on multiple spiral CT data before and after surgery.

RESULTS

The bone defects healed well when the periosteum was preserved, whereas they healed poorly with residual bone defects when the periosteum was resected after surgery. When the periosteum was resected, the decrease in the mean thickness of the mandibular body was more than that of the contralateral side after surgery. In group I, about 66.7% of the animals exhibited mandible deviation at 24 weeks after surgery. The median point of mentum was inclined toward the side that the periosteum was preserved. In groups II and III, no mandible deviation was observed.

CONCLUSION

The periosteum plays an important role in bone growth and fracture healing. Mandibular outer cortex osteotomy inhibited the mandibular development and resulted in postoperative mandibular deviation in young miniature pigs. The simultaneous periosteum resection may offset the phenomenon of mandibular deviation to a certain extent.

Facial contouring surgery for asians

Asian people, especially women, prefer a more delicate and feminine facial shape. To achieve a softer and better facial contour, there are several procedures to change the facial skeleton. Reduction malarplasty and mandibular angleplasty are common facial contouring operations in Asia. A lot of techniques have been developed independently by several authors. Various approaches can be chosen, such as intraoral or external skin incisions. There as also different contouring methods that can be chosen depending on the patient's morphology and the surgeon's technical preferences. The different osteotomy techniques used to mobilize the zygomatic complex can be classified according to the specific portion that is being repositioned. Resection and contouring methods for a prominent mandibular angle can be subdivided according to the specific type of anomaly. The purpose of this article is to review the concepts and various operative procedures for reduction malarplasty and angleplasty. The authors propose a guideline for selecting the appropriate procedure(s) for individual patients. Decisions should be made according to the patient's need, anatomic variations, and possible operative sequelae.

Combined long-curved ostectomy in the inferior mandibular border and angle of the mandible with splitting corticectomy for reduction of the lower face

BACKGROUND

In Asian countries, a square-shaped face is considered unattractive. Many operative techniques have been developed and reported for reduction of the lower face, including mandibular angle ostectomy and splitting corticectomy. Many surgeons have performed the operation in the angle region using one of the aforementioned techniques, which may not lead to effective results. This report mainly discusses the standard procedures of surgery.

METHODS

To overcome the drawbacks of conventional procedures and to perform ostectomy accurately, proper preoperative analysis and design were implemented for 159 patients with square-shaped faces. Based on a new type of classification and concepts for mandible reduction, long-curved ostectomy combined with splitting corticectomy was used for reduction of the lower face. A series of standard procedures was developed during the operative process.

RESULTS

The majority of patients were satisfied with both their frontal and lateral appearances. The gonial angle and the mandibular plane angle were increased effectively. No major complications such as fracture or facial nerve damage occurred. Lip numbness occurred for 15% of the patients.

CONCLUSIONS

The authors' series of standard procedures allows surgeons to perform accurate, safe, and reproducible ostectomy and to obtain reliable and stable effects.

[Comparative analysis of linear morphometric parameters of the humane mandibula obtained by direct and indirect measurement]

BACKGROUND/AIM

Reconstruction of lost, damaged or distorted mandibular bone presents a challenge from the functional side, as well as from the esthetic point of view. The aim of this study was to determinate potential differences between values of the basic linear moprhometric parameters (LMPs) obtained by direct and indirect manual measurement of the same humane mandibles, with accuracy testing of indirect measurement, which are routinely used in every-day clinical practice. The results are essential for defining of parametric model of the "standard mandible" and virtual modeling of the humane mandible in future researches as well as in clinical medicine.

METHODS

A total number of 12 dry bony mandibles of human adults were studied. According to the standard anatomical landmarks, 10 standard LPMs were measured on each mandible by different manual methods: directly by a sliding caliper with nonius, and indirectly using standard software on two-dimensional (2D) reconstructions of mandibular multislice computed tomography (MSCT) scans. The values obtained by the different measuring methods were matched for the same LMPs.

RESULTS

Statistically significant differences between compared LMPs values obtained by different measuring methods, appeared in the gnathio-interdental distance (Gn-IdD), as well as in the gnathio-condylar distance (Gn-CoD), bilaterally. In both parameters, significantly higher mean values (with percent of difference) were obtained by direct versus indirect measurement: Gn-IdD (21.57%; 29.2 mm vs 22.9 mm; p = 0.004); Gn-CoD left side (14.1%; 122.7 mm vs 105.4 cm; p = 0.001); Gn-CoD right side (11.87%; 124.7 mm vs 109.9 mm; p = 0.009).

CONCLUSION

According to the observed inaccuracy of indirect measurement, we recommended the use of a correction factor for calculation of both Gn-IdD and Gn-CoD real vales, in defining of parametric model of the "standard mandible" based on indirect morphometry on 2D reconstructions of mandibular MSCT scans. Additional studies with larger number of specimens and quantification of anatomical variations regarding to sex, age, dentition status and ethnic origin, additionally should increase measurement accuracy and consequently reliability of future parametric model of the human mandible.

Effect of outer mandibular cortex osteotomy on local morphology and biomechanics in young miniature pigs

AIM

The purpose of this study was to research the effect of outer mandibular cortex osteotomy on local morphology and biomechanics in young miniature pigs.

METHODS

Eight 3-month-old miniature pigs were used as experimental animals to establish an animal model for removing the outer cortex of the mandibular body, and the changes in local morphology, fine structure, and biomechanics of the mandible after the operation were evaluated.

RESULTS

The thickness of the operated side decreased to a greater extent than that of the control side. Further, local histologic structure and biomechanics characteristics could be recovered under stress conditions and were close to those of the normal side after the operation. However, some animals (37.5%) exhibited mandible deviation after operation.

CONCLUSION

Under normal conditions, mandibular outer cortex osteotomy should not be performed in the case of children.