Automatic 3-Dimensional Cephalometric Landmarking via Deep Learning.

The increasing use of 3-dimensional (3D) imaging by orthodontists and maxillofacial surgeons to assess complex dentofacial deformities and plan orthognathic surgeries implies a critical need for 3D cephalometric analysis. Although promising methods were suggested to localize 3D landmarks automatically, concerns about robustness and generalizability restrain their clinical use. Consequently, highly trained operators remain needed to perform manual landmarking. In this retrospective diagnostic study, we aimed to train and evaluate a deep learning (DL) pipeline based on SpatialConfiguration-Net for automatic localization of 3D cephalometric landmarks on computed tomography (CT) scans. A retrospective sample of consecutive presurgical CT scans was randomly distributed between a training/validation set (n = 160) and a test set (n = 38). The reference data consisted of 33 landmarks, manually localized once by 1 operator(n = 178) or twice by 3 operators (n = 20, test set only). After inference on the test set, 1 CT scan showed "very low" confidence level predictions; we excluded it from the overall analysis but still assessed and discussed the corresponding results. The model performance was evaluated by comparing the predictions with the reference data; the outcome set included localization accuracy, cephalometric measurements, and comparison to manual landmarking reproducibility. On the hold-out test set, the mean localization error was 1.0 ± 1.3 mm, while success detection rates for 2.0, 2.5, and 3.0 mm were 90.4%, 93.6%, and 95.4%, respectively. Mean errors were -0.3 ± 1.3° and -0.1 ± 0.7 mm for angular and linear measurements, respectively. When compared to manual reproducibility, the measurements were within the Bland-Altman 95% limits of agreement for 91.9% and 71.8% of skeletal and dentoalveolar variables, respectively. To conclude, while our DL method still requires improvement, it provided highly accurate 3D landmark localization on a challenging test set, with a reliability for skeletal evaluation on par with what clinicians obtain.

Interaction between posture and maxillomandibular deformity: a systematic review.

Maxillomandibular deformity (MMD) and body posture appear to be correlated. However, no systematic literature review of the available evidence to support this correlation has been performed to date. The aim of this study was to conduct a systematic literature review on posture and MMD. This systematic literature review was registered in the PROSPERO database. Systematic searches of the MEDLINE, Scopus, Cochrane Library, and Web of Science databases were performed. In total, 13 clinical studies were included. Nine found a significant association between MMD and body posture or body balance: two studies showed a correlation between increased cervical lordosis and skeletal class III MMD, two studies showed an interaction between mandibular deviation and scoliosis, four studies demonstrated a significant association between lumbar column and pelvis anatomy and MMD, and one study found a correlation between displacement of the centre of mass and MMD. However, the level of evidence is low; the methods used to evaluate body posture and MMD were inconsistent. Orthognathic surgery could modify body posture. Although there seems to be an interaction between body posture and facial deformity, the number of studies is too small and the level of evidence too low to strongly support this association.

Intra-sinusal bone ring concomitant with Le Fort 1 osteotomy: description of a technique.

AIM: To present a technical note on intra-sinusal bone ring concomitant with Le Fort 1 osteotomy. MATERIAL AND METHOD: A 57-year-old man was referred to our Department for full-mouth rehabilitation. Oral examination identified: uncompensated multiple tooth loss and a class 3 skeletal malocclusion. The treatment plan consisted in a Le Fort 1 osteotomy and short-arch dental implant rehabilitation. Intra-sinusal bone ring technique associated with Le Fort 1 osteotomy were carried out under general anaesthesia. RESULT: High primary retention was clinically observed of both the implant and the bone graft. Radiographic follow-up demonstrated satisfactory healing of the graft and implant osseointegration. CONCLUSION: Bone ring technique concomitant with Le Fort 1 osteotomy seems to be appropriate to correct jaw discrepancy associated to a single tooth loss of the upper molar region with residual bone height of at least 3 mm to ensure implant primary stability.

Accuracy and reliability of automatic three-dimensional cephalometric landmarking.

The aim of this systematic review was to assess the accuracy and reliability of automatic landmarking for cephalometric analysis of three-dimensional craniofacial images. We searched for studies that reported results of automatic landmarking and/or measurements of human head computed tomography or cone beam computed tomography scans in MEDLINE, Embase and Web of Science until March 2019. Two authors independently screened articles for eligibility. Risk of bias and applicability concerns for each included study were assessed using the QUADAS-2 tool. Eleven studies with test dataset sample sizes ranging from 18 to 77 images were included. They used knowledge-, atlas- or learning-based algorithms to landmark two to 33 points of cephalometric interest. Ten studies measured mean localization errors between manually and automatically detected landmarks. Depending on the studies and the landmarks, mean errors ranged from <0.50mm to>5mm. The two best-performing algorithms used a deep learning method and reported mean errors <2mm for every landmark, approximating results of operator variability in manual landmarking. Risk of bias regarding patient selection and implementation of the reference standard were found, therefore the studies might have yielded overoptimistic results. The robustness of these algorithms needs to be more thoroughly tested in challenging clinical settings. PROSPERO registration number: CRD42019119637.

A retrospective study of pure medial orbital wall fracture management.

PURPOSE: To describe the clinical presentation of isolated medial orbital wall fractures, the duration of symptoms and their management. METHODS: Retrospective study of 60 orbits of 60 patients over 18 years of age with isolated medial wall fractures of the orbit at the facial and trauma center of the Pitié-Salpêtrière university hospital of Paris between June 2012 and November 2015. Diplopia, enophthalmos and limitation of extraocular muscle movements were investigated. The location of the fractures was confirmed with three-dimensional computed tomography. Intraocular trauma was ruled out. Incomplete data were excluded. RESULTS: Eighty-three patients were identified (June 2012-November 2015). Sixty patients (39 males and 21 females) had a complete medical record. The mean age was 37 years, ranging from 18 to 75 years. Assault was the most common cause in 45 patients (75%), followed by sports accidents in 8 patients (13%), motor vehicle accidents in 6 patients (10%), and a fall in 1 patient. On presentation, 51 patients (85%) had no symptoms. Diplopia was present in 9 patients (15%). Four of them (6.7%) had associated enophthalmos. The diplopia resolved spontaneously in 5 patients (5.5%) and persisted more than 2 weeks in 4 patients (6.7%), for whom surgical intervention was recommended. Only 4 patients (6.7%) were managed surgically due to the presence of combined persistent diplopia and enophthalmos. The mean time from trauma to surgery was 18 days (15-45 days). At the 45-day postoperative follow-up, persistent diplopia was present in 1 patient out of the four treated surgically, with no residual enophthalmos. Fifty-six patients were managed conservatively. CONCLUSION: Asymptomatic fractures do not require surgical repair, and conservative management is adequate. Such fractures heal on their own without any consequences.

Gnathodiaphyseal dysplasia with a novel R597I mutation of ANO5: Mandibular reconstruction strategies.

Gnathodiaphyseal Dysplasia (GDD) is a rare, often misdiagnosed, autosomal-dominant disorder due to point mutations in the ANO5 gene. GDD combines craniofacial fibro-osseous lesions, dental loss and progressive curvature and cortical thickening of long bones and vertebra, causing pathological fractures. Diagnosis is based on bone pathology and mutation screening. Here we report three GDD cases within a single family with a novel ANO5 mutation: c.1790 G > T (p.Arg597Ile, i.e. R597I) on exon 16. Microsurgical mandibular reconstructions were performed in the three cases. We reviewed the literature on jaw reconstruction in this condition and discussed the challenges of craniofacial reconstruction in GDD due to the diffuse bone anomalies affecting potential flap donor zones and a specific risk for jawbone osteomyelitis.

Synovial chondromatosis of the temporomandibular joint: Report and analysis of 12 cases.

OBJECTIVE: We had for aim to study the clinical manifestations, diagnostic imaging techniques, histopathological and therapeutic findings of patients presenting with synovial chondromatosis (CS) of the temporomandibular joint (TMJ). MATERIAL AND METHODS: We reviewed the clinical history of all our patients who were diagnosed with CS between 2009 and 2013. RESULTS: We identified 12 cases of TMJ-CS, in 4 male and 8 female patients, with a mean aged of 50.5 years at diagnosis (range: 43-86 years). The average symptom duration prior to diagnosis was 11 months (range: 1-24 months). The most frequent clinical manifestations were joint pain (10 cases), restricted movement (6 cases), and swelling (4 cases). Panoramic radiographs were not contributive. CT scan and MRI findings led to a diagnosis in every case. 2 to 30 foreign bodies with various degrees of aggregation were removed by arthrotomy in our series and synovectomy was performed in all patients. These foreign bodies were in the upper compartment and the articular disk was not affected in 10 cases. A histopathological examination confirmed the diagnosis. The mean postoperative follow-up was 78 months. No case of chondrosarcoma was identified and the recurrence rate was low (1 case). DISCUSSION: The clinical manifestations of TMJ-CS are common and conventional imaging is poorly contributive so that the diagnosis is often late. The delay before diagnosis was an average11 months for our patients given our experience; it was almost twice longer in other series. Arthrotomy and excision of the loose bodies led to confirmation by histopathological analysis. Most of the time, this treatment is sufficient but long term clinical and radiological monitoring is required.

A case of epistaxis.

The authors report a case of epistaxis in a 74-year-old male patient. His recent medical history documented recurrent nasal bleeding and a Le Fort 1 osteosynthesis 3 weeks before admission to our unit. A CT scan revealed a left descending palatine artery pseudoaneurysm in the left maxillary sinus that was successfully embolized. Pseudoaneurysms of the internal maxillary artery and its branches are rare life-threatening complications. This diagnosis should be considered when confronted to recurrent head and neck bleeding, especially in a context of recent maxillo-facial trauma or surgery. Embolization should rapidly be implemented.

The promising impact of molecular profiling on treatment strategies in oral cancers.

Oral squamous cell carcinoma (OSCC) is a major cause of cancer-associated morbidity and mortality. Although OSCC may develop from easily accessible oral preneoplastic lesions (OPLs), no intervention has been reported so far that reduces the rate of malignant transformation. A comprehensive molecular characterization of oral carcinogenesis may help refining treatment strategies both in patients with OPLs and OSCC. Herein, we review main molecular alterations occurring at different steps during oral carcinogenesis and show how molecularly-based medicine and surgery may impact the outcome of OSCC in the future.

Necrotizing sialometaplasia of the parotid gland associated with facial nerve paralysis.

INTRODUCTION: Necrotizing sialometaplasia is a benign inflammatory lesion involving most frequently the minor salivary gland of the hard palate. Involvement of the parotid gland is rare, involvement of the parotid gland associated with facial palsy is exceptional. CASE REPORT: A 56-year-old male patient with Marfan syndrome presented with swelling and inflammation of the left parotid gland associated with progressively complete facial nerve paralysis. CT scan and MRI showed a parotid collection with hyper signal of the nearest tissues associated with erosion of the styloid process. A malignant tumor was suspected. The histological examination of a biopsy showed a lobulocentric process with necrosis, squamous metaplasia, and inflammation. The immunohistochemical examination supported a final diagnosis of necrotizing sialometaplasia. DISCUSSION: Necrotizing sialometaplasia of the parotid gland associated with facial nerve paralysis presents like a malignant neoplasm, both clinically and histologically. Only advanced immunohistochemical examination can really confirm the diagnosis.

Zygomatic bone shape in intentional cranial deformations: a model for the study of the interactions between skull growth and facial morphology.

Intentional cranial deformations (ICD) were obtained by exerting external mechanical constraints on the skull vault during the first years of life to permanently modify head shape. The repercussions of ICD on the face are not well described in the midfacial region. Here we assessed the shape of the zygomatic bone in different types of ICDs. We considered 14 non-deformed skulls, 19 skulls with antero-posterior deformation, nine skulls with circumferential deformation and seven skulls with Toulouse deformation. The shape of the zygomatic bone was assessed using a statistical shape model after mesh registration. Euclidian distances between mean models and Mahalanobis distances after canonical variate analysis were computed. Classification accuracy was computed using a cross-validation approach. Different ICDs cause specific zygomatic shape modifications corresponding to different degrees of retrusion but the shape of the zygomatic bone alone is not a sufficient parameter for classifying populations into ICD groups defined by deformation types. We illustrate the fact that external mechanical constraints on the skull vault influence midfacial growth. ICDs are a model for the study of the influence of epigenetic factors on craniofacial growth and can help to understand the facial effects of congenital skull malformations such as single or multi-suture synostoses, or of external orthopedic devices such as helmets used to correct deformational plagiocephaly.

Prognostic factors of gingival-alveolar squamous cell carcinoma of the maxilla.

OBJECTIVES: To determine prognostic factors in gingivo-alveolar squamous cell carcinoma of the maxilla (GA-SCC-M), and particularly the prognostic value of both vertical and antero-posterior tumor spread. MATERIAL AND METHODS: Our retrospective study included all naïve-treatment patients treated in our center between 2006 and 2013 for GA-SCC-M. Posterior involvement was considered when the tumor extended behind the mesial side of the first maxillary molar. Spread posterior to the maxillary tuberosity was defined by the spread to at least one of the following structures: pterygomaxillary fissure, pterygoid muscles, and processes. Involvement of the maxillary sinus floor, nasal fossa, and orbital floor was assessed, concerning the vertical spread. RESULTS: A radiological tumor spread to the nasal fossa, maxillary sinus floor, and orbital floor were prognostic factors independently of age, cervical lymph node metastasis and positive margins in multivariate analysis (p < 0.05). Radiological suggested spread tended to be noticeably more predictive of a poor prognosis than histological proven tumoral spread. The prognosis was not significantly different between clinical tumoral spread anteriorly or posteriorly to the first molar (p = 0.46). The prognosis was not worsened, even in case of radiological suggested spread posterior to the maxillary tuberosity (p = 0.09). CONCLUSION: A vertical radiological spread of GA-SCC-M was a prognostic factor but not the extension posteriorly to the maxillary tuberosity. T4b tumors were mostly resectable, proving that a T4b stage was not predictive of unresectability in GA-SCC-M of the maxilla.

Influence of the overall stiffness of a load-bearing porous titanium implant on bone ingrowth in critical-size mandibular bone defects in sheep.

The aim of this work was to assess the influence of reduction of the apparent mechanical properties of fully load-bearing porous titanium implants used in mandibular bone defects. Segmental 18mm long bone defects were created bilaterally in the lower jaws of adult ewes. One group of 6 ewes (group A) was treated with load-bearing 'rigid' (high stiffness) porous implants on the right side, and with control on the left side. A second group of 6 ewes (group B) was treated with 'flexible' porous and control implants exhibiting apparent mechanical properties ten times lower than the rigid implants. The mechanical behavior of the reconstructed hemi-mandibles was assessed by cantilever testing and bone ingrowth into the segmental defects was assessed by BV/TV measurement within the implant using micro-CT 12 weeks after implantation. A significantly higher rigidity was identified for porous implants compared with control implants at the anterior interface in group B. BV/TV of porous implants was significantly higher than that of control implants in group A. BV/TV differences were significant between porous and control implants in group B and were homogeneous along the main axis. Significantly higher BV/TV was identified in most sub-volumes of group B porous implants compared with group A. This work highlights the critical importance of the tuning of scaffolds to promote bone ingrowth with reference to the local strains occurring within the porous scaffold, which in this application was achieved using fully load-bearing low-stiffness porous titanium implants.

Diffusion model to describe osteogenesis within a porous titanium scaffold.

In this study, we develop a two-dimensional finite element model, which is derived from an animal experiment and allows simulating osteogenesis within a porous titanium scaffold implanted in ewe's hemi-mandible during 12 weeks. The cell activity is described through diffusion equations and regulated by the stress state of the structure. We compare our model to (i) histological observations and (ii) experimental data obtained from a mechanical test done on sacrificed animal. We show that our mechano-biological approach provides consistent numerical results and constitutes a useful tool to predict osteogenesis pattern.

[Surgery guided by customized devices: reconstruction with a free fibula flap]. / Chirurgie assistée par dispositifs sur-mesure: reconstruction par lambeau libre de fibula.

The reconstruction of jaws with a free fibula flap can be anticipated virtually. The simulation can be transferred to the operating theater using customized devices obtained from computer-assisted design and manufacturing in a complete digital workflow. Several alternatives are available, from cutting guides to customized titanium osteosynthesis plates, to obtain the best accuracy and reproducibility of reconstruction. Moreover, these new processes allow integrating prosthetic planning concomitantly with reconstruction. We present the virtual three-dimensional planning method for jaw reconstruction with a free fibula flap and the various alternatives of surgery guided by customized devices provided by this planning.

[Accuracy of morphological simulation for orthognatic surgery. Assessment of a 3D image fusion software]. / Précision des prédictions morphologiques en chirurgie orthognathique. Évaluation d'un procédé de fusion d'images 3D.

INTRODUCTION: The CT/CBCT data allows for 3D reconstruction of skeletal and untextured soft tissue volume. 3D stereophotogrammetry technology has strongly improved the quality of facial soft tissue surface texture. The combination of these two technologies allows for an accurate and complete reconstruction. The 3D virtual head may be used for orthognatic surgical planning, virtual surgery, and morphological simulation obtained with a software dedicated to the fusion of 3D photogrammetric and radiological images. TECHNICAL NOTE: The imaging material include: a multi-slice CT scan or broad field CBCT scan, a 3D photogrammetric camera. The operative image processing protocol includes the following steps: 1) pre- and postoperative CT/CBCT scan and 3D photogrammetric image acquisition; 2) 3D image segmentation and fusion of untextured CT/CBCT skin with the preoperative textured facial soft tissue surface of the 3D photogrammetric scan; 3) image fusion of the pre- and postoperative CT/CBCT data set virtual osteotomies, and 3D photogrammetric soft tissue virtual simulation; 4) fusion of virtual simulated 3D photogrammetric and real postoperative images, and assessment of accuracy using a color-coded scale to measure the differences between the two surfaces.