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Purpose: Bone defects of the inferior mandibular border (osseous inferior border defects) can cause unesthetic postoperative outcomes after bilateral sagittal split osteotomy (BSSO). The aim of this study was to estimate the frequency of osseous inferior border defects after BSSO and to identify risk factors for this complication., Materials and Methods: This retrospective study included consecutive patients who underwent BSSO for mandibular retrognathia. The primary outcome was the presence/absence of osseous inferior border defects. Predictors included the mandibular movement, rotation of the occlusal plane, postoperative proximal segment position, pattern of lingual fracture, occurrence of bad split, and presence of third molars., Results: The study sample consisted of 200 patients and had a mean follow-up of 13 months. The mean mandibular advancement and rotation was respectively 5.8 mm and 5.4° clockwise. Osseous inferior border defects were present in 7.0% of splits and in 12.5% of patients. Significant risk factors for inferior border defects included increased advancement, increased clockwise rotation, cranial rotation of the proximal segment, and a split originating in the lingual cortex., Conclusion: In conclusion, osseous inferior border defects occur significantly more often in cases with large mandibular advancement, increased clockwise rotation of the occlusal plane, malpositioning of the proximal segment, and a split originating in the lingual cortex., (Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Purpose: The aim of this study was to evaluate the usefulness of intra-operative visualisation, endoscopic assistance, and CT measurements for estimating the orbital fracture size and complexity., Methods: Ten human cadaver heads were subjected to thin-slice computed tomography (CT). Standardised fractures were created using piezoelectric surgery in accordance with the Jaquiéry classification system. Four surgeons and one anatomist used six different observation methods to visualise and describe the orbital defects., Results: The intraclass correlation coefficients (ICCs) for the fracture length measurements were relatively low for all observation methods (range, 0.666-0.883). CT measurements of width showed high consistency (ICC, 0.910). The surface area of the defect was highly overestimated by all methods (range, 121-184%). None of the observers was able to accurately estimate the length or width of 95% of the defects within an error range of ±0.75 cm., Conclusion: CT measurements are the most consistent and accurate tool for estimating the critical size of orbital factures. In daily practice, a measurement tool in a DICOM viewer could be used, although software packages that allow manual adjustments are advisable. Direct intraoperative visualisation and surgeon experience are of limited value in the estimation of fracture size and complexity, and endoscopy provides no additional advantages., (Copyright © 2016. Published by Elsevier Ltd.)

The aim of this study was to evaluate the outcomes of coronectomy as an alternative surgical procedure to complete removal of the impacted mandibular third molar in patients with a suspected close relationship between the tooth root(s) and the mandibular canal. A total of 151 patients underwent coronectomy and were followed up with clinical examinations and panoramic radiographs for a minimum of 6 months after surgery. None of the patients exhibited inferior alveolar nerve injury. Eruption of the retained root(s) was more frequent in younger patients (18-35 years). Thirty-six patients (23.8%) exhibited insufficient growth of new bone in the alveolar defect, and 11.3% required a second surgical procedure to remove the root remnant(s). Our results indicate that coronectomy can be a reliable alternative to complete removal of the impacted mandibular third molar in patients exhibiting an increased risk of damage to the inferior alveolar nerve on panoramic radiographs., (Copyright © 2016. Published by Elsevier Ltd.)

Purpose: The purpose of this study was to validate a quick, accurate and reproducible (semi-) automatic software segmentation method to measure orbital volume in the unaffected bony orbit. Precise volume measurement of the orbital cavity is a useful addition to pre-operative planning and intraoperative navigation in orbital reconstruction., Methods: In 21 CT scans, one unaffected orbit was selected to compare manual segmentation (gold standard) with three segmentation methods using iPlan software (version 3.0.5; Brainlab, Feldkirchen, Germany): automatic (method A), automatic minus bone/air masks (method SA) and automatic minus masks followed by manual adjustments (method SAA). First, validation of the manual segmentation and a newly described method for the anterior boundary was performed. Subsequently the accuracy, reproducibility and time efficiency of the methods were examined. Measurements were performed by two observers., Results: The intraclass correlation for the interobserver agreement of the anterior boundary was 0.992, and the intraobserver and interobserver agreement for the manual segmentation were 0.997 and 0.994, respectively. Method A had an average volumetric difference of 0.49 cc (SD 0.74) in comparison with the gold standard; this was 0.24 cc (SD 0.27) for method SA and 0.86 cc (SD 0.27) for method SAA. The average time for each method was 38 (SD 5.4), 146 (SD 16.0) and 327 (SD 36.2) seconds per orbit., Conclusion: The built-in automatic method A is quick, but suboptimal for clinical use. The newly developed method SA appears to be accurate, reproducible, quick and easy to use. Manual adjustments in method SAA are more time-consuming and do not improve volume accuracy. The largest volume discrepancy is located near the inferior orbital fissure.

The goal of orbital reconstruction is to repair trauma defects, to correct the position of the eye anatomically, avoiding enophthalmos, and to restore ocular function. For the reconstruction of (trauma) defects, many surgeons recommend materials that can be bent into an anatomical shape and that possess the properties of radiopacity and long-term stability. However, apart from these desired properties, the ideal material for orbital reconstruction remains controversial. Autologous bone is often mentioned as the 'gold standard,' likely because of its mechanical properties, revascularization potential, and its adaptation to the orbital tissue with minimal acute and chronic immune reactivity. However, autologous bone can show unpredictable resorption rates and suboptimal volume correction. In recent years, an increasing interest in the use of alloplasts for orbital reconstruction has become apparent in the literature. Modern technological advantages, such as preoperative planning, navigation, and perioperative imaging, can be beneficial in the decision to choose a certain implant. The aim of this review is to give a comprehensive overview of the advantages and disadvantages of materials used to reconstruct traumatic orbital defects and to provide a practical, evidence-based, complexity-driven set of guidelines., (Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Preformed orbital reconstruction plates are useful for treating orbital defects. However, intraoperative errors can lead to misplaced implants and poor outcomes. Navigation-assisted surgery may help optimize orbital reconstruction. We aimed to explore whether navigation-assisted surgery is more predictable than traditional orbital reconstruction for optimal implant placement. Pre-injury computed tomography scans were obtained for 10 cadaver heads (20 orbits). Complex orbital fractures (Class III-IV) were created in all orbits, which were reconstructed using a transconjunctival approach with and without navigation. The best possible fit of the stereolithographic file of a preformed orbital mesh plate was used as the optimal position for reconstruction. The accuracy of the implant positions was evaluated using iPlan software. The consistency of orbital reconstruction was lower in the traditional reconstructions than in the navigation group in the parameters of translation and rotation. Implant position also differed significantly in the parameters of translation (p = 0.002) and rotation (pitch: p = 0.77; yaw: p < 0.001; roll: p = 0.001). Compared with traditional orbital reconstruction, navigation-assisted reconstruction provides more predictable anatomical reconstruction of complex orbital defects and significantly improves orbital implant position., (Copyright © 2015. Published by Elsevier Ltd.)

Navigation-assisted orbital reconstruction remains a challenge, because the surgeon focuses on a two-dimensional multiplanar view in relation to the preoperative planning. This study explored the addition of navigation markers in the implant design for three-dimensional (3D) orientation of the actual implant position relative to the preoperative planning for more fail-safe and consistent results. Pre-injury computed tomography (CT) was performed for 10 orbits in human cadavers, and complex orbital fractures (Class III/IV) were created. The orbits were reconstructed using preformed orbital mesh through a transconjunctival approach under image-guided navigation and navigation by referencing orientating markers in the implant design. Ideal implant positions were planned using preoperative CT scans. Implant placement accuracy was evaluated by comparing the planned and realized implant positions. Significantly better translation (3.53 mm vs. 1.44 mm, p = 0.001) and rotation (pitch: -1.7° vs. -2.2°, P = 0.52; yaw: 10.9° vs. 5.9°, P = 0.02; roll: -2.2° vs. -0.5°, P = 0.16) of the placed implant relative to the planned position were obtained by implant-oriented navigation. Navigation-assisted surgery can be improved by using navigational markers on the orbital implant for orientation, resulting in fail-safe reconstruction of complex orbital defects and consistent implant positioning., (Copyright © 2015. Published by Elsevier Ltd.)

In the treatment of orbital defects, surgeon errors may lead to incorrect positioning of orbital implants and, consequently, poor clinical outcomes. Endoscopy can provide additional visualization of the orbit through the transantral approach. We aimed to evaluate whether endoscopic guidance during orbital reconstruction facilitates optimal implant placement and can serve as a convenient alternative for navigation and intra-operative imaging. Ten human cadaveric heads were subjected to thin-slice computed tomography (CT). Complex orbital fractures (Class III/IV) were created in all eligible orbits (n = 19), which were then reconstructed using the conventional transconjunctival approach with or without endoscopic guidance. The ideal implant location was digitally determined using pre-operative CT images, and the accuracy of implant placement was evaluated by comparing the planned implant location with the postoperative location. There were no statistically significant differences (p > 0.05) in the degree of implant dislocation (translation and rotation) between the transconjunctival orbital reconstruction and the endoscopic-assisted orbital reconstruction groups. Endoscopic-assisted orbital reconstruction may facilitate the visualization of orbital defects and is particularly useful for training purposes; however, it offers no additional benefits in terms of accurate implant positioning during the anatomical reconstruction of complex orbital defects., (Copyright © 2015. Published by Elsevier Ltd.)

The timing of orbital reconstruction is a determinative factor with respect to the incidence of potential postoperative orbital complications. In orbital trauma surgery, a general distinction is made between immediate (within hours), early (within 2 weeks), and late surgical intervention. There is a strong consensus on the indications for immediate repair, but clinicians face challenges in identifying patients with minimal defects who may actually benefit from delayed surgical treatment. Moreover, controversies exist regarding the risk of late surgery-related orbital fibrosis, since traumatic ocular motility disorders sometimes recover spontaneously and therefore do not necessarily require surgery. In this study, all currently available evidence on timing as an independent variable in orbital fracture reduction outcomes for paediatric and adult patients was systematically reviewed. Current evidence supports guidelines for immediate repair but is insufficient to support guidelines on the best timing for non-immediate orbital reconstruction., (Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

In the 1980s, computed tomography was introduced as an imaging modality for diagnosing orbital fractures. Since then, new light has been shed on the field of orbital fracture management. Currently, most surgeons are likely to repair orbital fractures based on clinical findings and particularly on data obtained from computed tomography scans. However, an important but unresolved issue is the fracture size, which dictates the extent and type of reconstruction. In other fields of trauma surgery, an increasing body of evidence is stressing the importance of complexity-based treatment models. The aim of this study was to systematically review all articles on orbital reconstruction, with a focus on the indication for surgery and the defect size and location, in order to identify the reconstruction methods that show the best results for the different types of orbital fractures., (Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)