Impact of Mandibular Symphyseal Distraction Osteogenesis (MSDO) on the Sagittal Dimension and Long-Term Skeletal stability.

OBJECTIVE: To evaluate the long-term effects of mandibular symphyseal distraction osteogenesis (MSDO) on the correction of class II malocclusion correction and dental crowding. MATERIALS AND METHODS: Twenty-two patients received MSDO and presented class II malocclusion with transverse mandibular discrepancy. The authors collected data on 2 different cephalometric analyses. On Tweed analysis, The authors recorded ANB, SNA, SNB, and FMA angles. On Delaire analysis, we recorded the distance from Pti (pterygoid inferior) to ENAt (anterior nasal spine) and the distance from Cos (superior condyle) to Pog (pogonion). Superimpositions studies were performed at pre-treatment phase (T1) and post-treatment phase (T2) to evaluate the new position and changes in the dimensions of the mandible and maxilla. RESULTS: On superimposition of Tweed analysis of T1 and T2, reduction of ANB was seen in 18 patients, no change in ANB in 2 patients, and increase in ANB (by 1 deg) in 2 patients. Superimposition of Delaire analysis showed a mean difference of 0.3 mm (SD, 3.6 mm) between T1 and T2 for the maxilla and a mean difference of 6.0 mm (SD, 7.3 mm) for the mandible. CONCLUSIONS: Mandibular symphyseal distraction osteogenesis performed after the pubertal growth peak can effectively correct class II malocclusion and dental crowding with a single light surgical procedure.

Radiographic volumetric risk factors for late enophthalmos prediction in orbital blow-out fractures: A retrospective study.

The aim of this study was to assess the correlation between volumetric risk factors, orbital volume (OV), orbital volume ratio (OVR), herniated volume (HV), and the newly described herniated volume ratio (HVR), with the occurrence of late enophthalmos. Patients presenting a unilateral unoperated blow-out fracture were retrospectively included. OV and HV were measured using planimetry on the initial CT scan images. OVR and HVR were then calculated. Enophthalmos was measured on the 2-month follow-up CT scan images. The population was divided into two groups according to their enophthalmos status. Correlations and multiple linear regression model were used. 17 patients out of 45 presented a late enophthalmos of 1 mm or more. There were significantly higher OVR (107 (3.76); p < 0.0001), HV (0.8 (0.47); p < 0.0001) and HVR (3.3 (1.82); p < 0.0001) in the enophthalmos group. A very strong linear correlation between enophthalmos and OVR (rs = 0.806), HV (rs = 0.948) and HVR (rs = 0.951) was found. Enophthalmos prediction using these volumetric parameters can help the surgeon's decision-making in orbital blow-out fractures in order to prevent late enophthalmos. Measurement is simple and reproducible. However, larger prospective studies are needed to confirm these results.

Overview of tools for the measurement of the orbital volume and their applications to orbital surgery.

There are numerous applications in craniofacial surgery with orbital volume (OV) modification. The careful management of the OV is fundamental to obtain good esthetic and functional results in orbital surgery. With the growth of computer-aided design - computer-aided manufacturing (CAD-CAM) technologies, patient-specific implants and custom-made reconstruction are being used increasingly. The precise measurement of the OV before surgery is becoming a necessity for craniofacial surgeons. There is no consensus on orbital volume measurements (OVMs). Manual segmentation of computed tomography (CT) images is the most used method to determine the OV, but it is time-consuming and very sensitive to operator errors. Here, we describe the various methods of orbital volumetry validated in the literature that can be used by surgeons in preoperative planning of orbital surgery. We also describe the leading software employed for these methods and discuss clinical use (posttraumatic enophthalmos prediction and orbital reconstruction) in which OVMs are important.

Prediction of Post-Traumatic Enophthalmos Based on Orbital Volume Measurements: A Systematic Review.

PURPOSE: Enophthalmos greater than 2 mm should be considered clinically relevant and can be responsible for esthetic and functional morbidity. The difficulty has always been the best method to use to accurately determine when the orbital wall displacement will lead to clinically relevant enophthalmos. None of the currently used techniques is able to accurately predict for post-traumatic enophthalmos (PE). The aim of the present study was to systematically review the use of orbital volumetric tools in the prediction of PE after orbital fracture. MATERIALS AND METHODS: The terms searched in each database were "(orbital volumetry) and enophthalmos," "volumetry and enophthalmos," "volume and enophthalmos," and "volumetric and enophthalmos." The relationship between PE and the orbital volume (OV) was assessed. RESULTS: The initial search yielded 346 results. Of the 346 studies, 14 were included and analyzed. Every study reported a different numerical relationship between the OV and PE, with a mean enophthalmos of 0.80 mm after a 1-cm3 increase in the OV. CONCLUSIONS: The present review found that most studies concluded that a direct relationship exists between the OV and PE and defined the degree of PE in relation to the OV expansion. Enophthalmos assessment using radiologic evaluation provides increased accuracy and reproducibility compared with clinical measurement using an exophthalmometer. It has been notoriously difficult to determine when orbital wall displacement will lead to clinically relevant enophthalmos. Measurement of the OV could have a role in the decision for surgical or conservative treatment.

A New Orbito-Zygomatic Complex Reconstruction Technique Using Computer-Aided Design and Manufacturing-Assisted Harvest of Autologous Calvarial Bone in Cases of Orbito-Zygomatic Benign Tumor.

The orbito-zygomatic complex (OZC) includes several key structures, and its destruction leads to the impairment of functional activities such as nutrition, communication, nasal support, and vision. Management of benign tumors of the OZC is therefore a surgical challenge because of the necessity for reconstruction of these elements. Autogenous bone is considered the gold standard for reconstruction. Nevertheless, there is difficulty related to the complex anatomy and distorted skeletal anatomic landmarks, which require precise work in the case of bone grafts. The aim of this report is to propose a new reconstruction technique consisting of OZC reconstruction with computer-aided design and manufacturing of autologous calvarial bone. Three cases are presented. After performing tumor resection using computer-aided design and manufacturing cutting guides, we used a piezotome to perform osteotomies and preserve the periosteum and sinus mucosa. The SinpliciTi system (Materialise, Châtillon, France) allowed us to make cutting guides and a 3-dimensional surgical plan of the shapes and ideal positions of the calvarial bony plates for the OZC reconstruction. Calvarial osteotomies were performed using a piezotome through the polyamide calvarial cutting guide to obtain the shapes designed beforehand. Once the samples were collected, the shapes could be assembled ex vivo and then put in place through a minimally invasive approach. We discuss the advantages and limitations of our reconstruction method and its place in the management of OZC reconstruction.