Total mandibular subapical osteotomy and Le Fort I osteotomy using piezosurgery and computer-aided designed and manufactured surgical splints: a favorable combination of three techniques in the management of severe mouth asymmetry in Parry-Romberg syndrome

Treatment of Progressive Hemifacial Atrophy by Cartilage Graft and Free Adipofascial Flap Combined with Three-Dimensional Planning

BACKGROUND

Progressive hemifacial atrophy (PHA) is a rare disease characterized by progressive atrophy of skin, soft tissue, muscles, and underlying bone structures. For severe PHA patients with obvious bone deformities, skeletal framework reconstruction is needed in addition to soft-tissue augmentation. The authors propose a new combinatorial surgical method using rib cartilage graft and free adipofascial flap for restoring facial symmetry. To improve the surgical accuracy, preoperative three-dimensional planning and printing was used.

METHODS

Twelve patients with severe facial atrophy were included in the authors' study. Three-dimensional facial image analyses were performed preoperatively to quantify the facial asymmetry. Rib cartilages were harvested and sculptured to the appropriate shape created by three-dimensional planning and fixed to the atrophic bone. The circumflex scapular artery-based adipofascial flap was transplanted to repair soft-tissue deficiency. A residual small monitor flap was left with the adipofascial flap. A revision surgery was performed to perfect the repair if the contour was suboptimal 6 months postoperatively.

RESULTS

The adipofascial flaps survived in all 12 patients. All patients achieved good healing without complications. At 1 more year after surgery, the rib cartilage was still in position and rarely absorbed. The morphologic and volumetric difference between the affected side and the unaffected side was improved significantly postoperatively. All patients were satisfied with the results, and no more additional operations were required.

CONCLUSION

The combinatorial surgery of rib cartilage graft and free adipofascial flap in the setting of three-dimensional planning and printing can be a good choice in restoring facial symmetry in severe cases of PHA.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

[Localized scleroderma]

Localized scleroderma (LS), also called circumscribed scleroderma or morphea, comprises a heterogeneous group of diseases that can be classified into four subtypes: limited, linear, generalized, and mixed LS. All manifestations are primarily due to chronic progressive fibrosis of the skin or structures close to the skin. Involvement of internal organs or the transition to systemic sclerosis is excluded by definition. A distinction is made between forms that primarily affect the skin (up to the dermis) or that severely involve subcutaneous fat tissue, muscle fascia or muscles. A detailed examination is required for clinical diagnosis. In order to improve comparability of findings, photo documentation and the use of clinical scores should be carried out. For superficial subtypes the use of topical glucocorticosteroids, calcineurin inhibitors or phototherapy is initially recommended, whereas for severe forms with deep involvement or overall therapy refractoriness, the diagnosis should first be expanded and systemic therapy initiated at an early stage. Especially, in cross joint or extremity-dominant forms of linear LS or in cases with head and neck involvement, such as en coup de sabre, Parry-Romberg syndrome and other subtypes with a prominent musculoskeletal affection, an MRI examination should be arranged. Depending on location, an ophthalmological, neurological, orthodontic, rheumatological or orthopedic consultation may be necessary. For systemic therapy, methotrexate alone or in combination with systemic glucocorticosteroids as pulse therapy is recommended as first-line treatment.

A novel CAD/CAM composite occlusal splint for intraoperative verification in single-splint two-jaw orthognathic surgery

Background

Previous computer-generated splints were designed and produced without modification than the traditional occlusal splints, which did not facilitate surgeon's intraoperative judgment in the single-splint two-jaw orthognathic surgery. Modifications of the digital occlusal splint can be achieved using computer-aided design and computer-aided manufacturing (CAD/CAM) software. This study reported the design, clinical application and validation of a novel CAD/CAM occlusal splint.

Methods

The maxillary and mandibular segments were fixed into the final occlusal splint and moved to the planned position according to the 3-dimensional simulation. The composite occlusal splint has 4 orthogonal bars to facilitate intraoperative assessment of the dental and skeletal midline, facial soft tissue midline, occlusal plane, upper tooth show, facial symmetry and facial bone position. To validate the surgical outcome, 5 parameters including pitch, roll and yaw rotations, midline deviation and chin position were measured on the virtual plan and the postoperative cone-beam computed tomography images to quantify the difference.

Results

The results showed no significant differences in the 5 parameters between the simulation and postoperative images. The root-mean-square difference between the conventional splints and CAD/CAM surgical splint ranged from 0.18 to 0.31 mm by superimposition of the two image models. All patients were satisfied with the treatment outcomes. Overall, this novel occlusal splint is ideal for verification of the maxillomandibular position during surgery.

Conclusion

The novel composite occlusal splint provided useful and informative check to verify the maxillomandibular complex (MMC) position and facial appearance in single-splint two-jaw orthognathic surgery.

Evaluation of different fixation methods with finite element analysis in total mandibular subapical osteotomy

PURPOSE

The purpose of the study was to evaluate the stress distribution in various miniplates that were used in cases that underwent advancement with total mandibular subapical osteotomy (TMSO) using finite element analysis (FEA).

MATERIAL AND METHOD

Cone beam computed tomography (CBCT) images of a patient with appropriate bone tissues were used as a reference for the modeling of the mandible. In all mandibular models, horizontal TMSO was performed in a region 5 mm away from the apex of the teeth and vertical TMSO was performed in the retromolar region, 10 mm posterior to the second molar tooth. After TMSO, the dentoalveolar segment was advanced 3 mm and miniplates were placed symmetrically at four points for fixation. Four different miniplates with 2.0 mm thickness were used. Three different forces were applied to the models. Stress distribution on the models was evaluated using maximum von Mises stress values.

RESULTS

The maximum von Mises stress occurred in Y + I and Y + L models following the application of 300 N force from the incisal. An evaluation of posterior unilateral force indicated that the stress was remarkably high in the models with a posterior I-plate. The stress in the Y + I model was higher under unilateral force compared to the stress in other models. Under posterior bilateral force, the maximum von Mises stress values ​​occurred in the I-plates of T + I, Y + I, and L + I models (1006, 1012, and 1004 MPa, respectively).

CONCLUSION

Within the limitations of our study, we found that the ideal stress distribution was in the T + L and L + L plate combinations in the plates used for fixation after advancement with TMSO.

CBCT study on the positional relationship between marginal points of pterygomaxillary junction and anterior nasal spine

PURPOSE

This study aimed to locate the inferior end (Pti) and the superior end (Pts) of pterygomaxillary junction (PMJ) relative to anterior nasal spine (ANS) so as to provide references for pterygomaxillary separation.

METHODS

The study was based on CBCT images of 109 Chinese patients. We projected Pti and Pts to the frontal plane and measured the distance as well as the positional relationship between the projection points and ANS via three-dimensional reconstruction image.

RESULTS

On average, the ANS was 5.18 mm above the Pti and the horizontal distance between the Pti and ANS was 21.86 mm. The horizontal and vertical distances between Pts and ANS was 20.41 mm and 10.91 mm, respectively. The vertical height of PMJ was 16.09 mm. Scatter plots diagrammatic centered on ANS showed that 73% (160/218) Pti and 64% (140/218) Pts appeared in a 45° fan shape ranged from 20 to 25 mm radius in bilateral inferior and superior quadrant, respectively. There was no significant difference in the distance between both sides (P > 0.05).

CONCLUSION

During the pterygomaxillary disjunction, it exists a risk of injuring neurovascular bundle of the pterygopalatine fossa 16.09 mm above the lowest border of the pterygomaxillary junction. The region within a 45° fan shape ranged in 20-25 mm radius in inferior quadrant centered on ANS might be suitable for the osteotome position. The positional relationship especially between the ANS and Pti found in this study provides a reference for surgeons during pterygomaxillary disjunction.

Computer-assisted osteotomy guides and pre-bent titanium plates improve the planning for correction of facial asymmetry

This study investigated the surgical outcomes and accuracy of computer-assisted osteotomy guides and pre-bent titanium plates in the treatment of patients with facial asymmetry. Thirteen patients with facial asymmetry undergoing bimaxillary orthognathic surgery were included. Virtual simulation of Le Fort I osteotomy, sagittal split ramus osteotomy, and genioplasty, if needed, was conducted on the preoperative three-dimensional model. Computer-assisted osteotomy guides and pre-bent titanium plates were produced and used in the actual operation. The postoperative outcome was assessed for facial symmetry and surgical accuracy. All patients were followed up for at least 18 months and their level of satisfaction was investigated. Use of the computer-assisted osteotomy guides and pre-bent titanium plates was successful in all patients. Maxillary canting, mandibular ramus inclination, and mandibular length were corrected on both sides postoperatively. Superimposition of the surgical simulation and postoperative images demonstrated favourable accuracy. Quantitative analysis revealed a mean linear difference of <0.60mm in the maxilla and 1.57mm in the mandible. All patients were satisfied with the surgical outcome; there were no complications or cases of relapse during follow-up. The application of computer-assisted osteotomy guides and pre-bent titanium plates achieved favourable outcomes and accuracy, improving planning for the correction of facial asymmetry.

Total Mandibular Subapical Alveolar Osteotomy to Correct Class II Division I Dentofacial Deformity

Introduction

Class II division I malocclusions are the most common dentofacial deformities seen in clinical practice. Severe cases or cases in which growth has ceased may require full correction combining orthodontic and surgical treatment. We report a case of a total mandibular subapical alveolar osteotomy, performed to correct a class II division I dentofacial deformity.

Case Report

A 19-year-old female patient was referred to the oral and maxillofacial surgery department at the Federal University of Paraná with chin aesthetic complaints as well as class II malocclusion. The proposed treatment was total mandibular subapical alveolar osteotomy, retaining the chin position and eliminating the need for genioplasty, since, although the patient presented with a class II dentofacial deformity, the chin was well positioned. Under general anesthesia, a “V-shaped” incision was conducted from the right retromolar region to the left retromolar region. A ring of cortical bone was removed around the mental foramen, with the aim to create a space around the mental nerve. Fixation was conducted with plates and screws of the 2.0 system. The patient on six-year follow-up showed osteotomy stability, a better overall occlusion, and outcome satisfaction.

Minimally invasive orthognathic surgery: a systematic review

Minimally invasive techniques are currently applied in many oral and maxillofacial surgical procedures, including orthognathic surgery. A systematic review on the application of potentially minimally invasive procedures in orthognathic surgery was performed to provide a clear overview of the relevant published data. Articles in English on minimally invasive orthognathic procedures, published in the scientific literature, were obtained from the PubMed, Embase, and Cochrane Library databases, and an additional manual search (revised 31 December 2016). After screening the abstracts and applying the eligibility criteria, 403 articles were identified. All articles reporting the potential for minimally invasive orthognathic surgery were included (n=44). The full papers were evaluated in detail and categorized as articles on a minimally invasive surgical approach (n=4), endoscopically assisted orthognathic procedures (n=17), or the use of a piezoelectric device in orthognathic surgery (n=25); two articles were each included in two categories. Although a small incision and minimal dissection is the basic principle of a minimally invasive technique, most articles (90.9%) reported the endoscope and piezoelectric instrument as important tools in minimally invasive orthognathic surgery. Evidence from available studies suggests that patients undergoing minimally invasive orthognathic surgery have less morbidity and make a faster recovery. Further research should aim to obtain higher levels of evidence.

Three-dimensional computer-assisted surgical simulation and intraoperative navigation in orthognathic surgery: a literature review

By incorporating three-dimensional (3D) imaging and computer-aided design and manufacturing techniques, 3D computer-assisted technology has been applied widely to provide accurate guidance for assessment and treatment planning in clinical practice. This technology has recently been used in orthognathic surgery to improve surgical planning and outcome. The modality will gradually become popular. This study reviewed the literature concerning the use of computer-assisted techniques in orthognathic surgery including surgical planning, simulation, intraoperative translation of the virtual surgery, and postoperative evaluation. A Medline, PubMed, ProQuest, and ScienceDirect search was performed to find relevant articles with regard to 3D computer-assisted orthognathic surgery in the past 10 years. A total of 460 articles were revealed, out of which 174 were publications addressed the topic of this study. The purpose of this article is to present an overview of the state-of-art methods for 3D computer-assisted technology in orthognathic surgery. From the review we can conclude that the use of computer-assisted technique in orthognathic surgery provides the benefit of optimal functional and aesthetic results, patient satisfaction, precise translation of the treatment plan, and facilitating intraoperative manipulation.

Modification of planned postoperative occlusion in orthognathic surgery, based on computer-aided design/computer-aided manufacturing-engineered preoperative surgical simulation

In orthognathic surgery, it is important to have a planned postoperative occlusion. A 3-dimensional preoperative simulation, based on 3-dimensional optically scanned occlusion data, can predict how the planned postoperative occlusion will affect the maxilla-mandibular relationship that results from orthognathic surgery. In this study we modified the planned postoperative occlusion, based on computer-aided design/computer-aided manufacturing-engineered preoperative surgical simulations. This modification made it possible to resolve the facial asymmetry of the patient successfully with a simple bilateral intraoral vertical ramus osteotomy and no additional maxillary or mandibular surgery.