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Background: In 2001, a 27-year-old man was diagnosed with a meningioma with skull bone involvement. A craniectomy was performed and a CMW-3 poly(methyl methacrylate) cranioplasty was manually manufactured to reconstruct the remaining cranial defect. In 2016, he complained about progressive neurologic impairment. A computed tomography scan revealed that the cranioplasty had fractured into 4 dislocated pieces. Removal was indicated, and during the same operation a polyetheretherketone patient-specific implant was inserted., Methods: The fractured cranioplasty was compared with freshly prepared CMW-3 specimens to determine whether the material properties had changed during 15 years in vivo. Gel permeation chromatography, microcomputed tomography, and flexural strength tests were performed. The fracture itself was analyzed using finite element analysis., Results: The polydispersity index and molecular weight were not significantly different for the fractured cranioplasty and CMW-3. The fractured cranioplasty contained a total porosity of 10.7%, fresh CMW-3 cured at atmospheric pressure contained 4.1%, and 0.06% when cured at 2.2 bar. The flexural strength of the CMW-3 cured at 2.2 bar was significantly higher than both the fractured cranioplasty and CMW-3 cured at atmospheric pressure. Finite element analysis showed stress of 12.2 MPa under a load of 100 N on a weak spot., Conclusions: This ex vivo study shows that CMW-3 after 15 years in vivo was not influenced in molecular weight or flexural strength. However, the design of the implant and the handling of the poly(methyl methacrylate) seem to be important factors to improve mechanical properties of cranial reconstructions., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: Unilateral condylar hyperplasia or hyperactivity (UCH) is a bone overgrowth disorder affecting the mandible. The purpose of this study was to determine the relations among age, condylar bone structure, condylar bone volume, and condylar bone activity on single-photon emission computed tomographic (SPECT) scans in patients with UCH., Materials and Methods: This study included 20 patients with a clinical presentation of progressive mandibular asymmetry and a positive bone SPECT scan. A bone SPECT-derived standardized uptake value (bSUV) for the condylar region was determined. All patients underwent condylectomy to arrest further progression of the disease. The resected condyles were scanned with a micro-computed tomographic scanner (18-μm resolution). Bone architectural parameters were calculated with routine morphometric software., Results: The mean bSUV of the condyle on the affected side was 15.32 (standard deviation [SD], 8.98) compared with 9.85 (SD, 4.40) on the nonaffected side (P = .0007). For trabecular bone structure, there was a nonsignificant correlation between the SUV of the affected condyle and the measured bone volume fraction (r = 0.13; P = .58) and trabecular thickness (r = 0.03; P = .90)., Conclusion: No meaningful relation was found between condylar bone volume fraction and condylar activity on bone scan; therefore, the impact of bone volume fraction on the results of bone scans is limited. The measured condylar activity on SPECT scan seems to be primarily a reflection of the remodeling rate of bone., (Copyright © 2018 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Currently, various materials are routinely used for cranioplasty after decompressive craniectomy, each with their own features, potential benefits, and harms., Objectives: To systematically review available literature about safety (infection, resorption, and removal) of different materials used for cranioplasty for any indication., Methods: A comprehensive search in MEDLINE, EMBASE, and the Cochrane library was performed for relevant studies published up to January 2017. Study quality was assessed according to the Cochrane Collaboration risk of bias assessment tool, and a set of 27 predetermined parameters was extracted by 2 investigators independently for further analysis., Results: The search yielded 2 randomized, 14 prospective, and 212 retrospective studies, totaling 10,346 cranioplasties in which 1952 (18.9%) complications were reported in patients between 0 and 90 years old. Overall, study quality was low and heterogeneity was large. Graft infections and resorption were most prevalent: overall infection rate was 5.6%. Autologous cranioplasties showed an infection rate of 6.9% versus 5.0% in combined alloplastic materials, including poly(methyl methacrylate) with 7.8%. Resorption occurred almost exclusively in autologous cranioplasties (11.3%). The greatest removal rate was reported for autologous cranioplasties (overall: 10.4%), which was significantly greater than that of combined alloplastic materials (overall: 5.1%; risk difference = 0.052 [95% confidence interval: 0.039-0.066]; NNT = 19 [95% confidence interval: 15-25])., Conclusions: Available evidence on the safety of cranioplasty materials is limited due to a large diversity in study conduct, patients included, and outcomes reported. Autografts appear to carry a greater failure risk than allografts. Future publications concerning cranioplasties will benefit by a standardized reporting of surgical procedures, outcomes, and graft materials used., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)

Purpose: Unilateral Condylar Hyperplasia (UCH) is an acquired deformity of the mandible, which can highly influence the symmetry of the face due to its progressive nature. It is caused by growth resembling pathology in one of the mandibular condyles. Definition as well as classification is subject to discussion. The aim of this study is to evaluate a large cohort of alleged UCH patients, and to describe the clinical characteristics, demographic features, classification and follow up. Secondly an algorithm is presented, in order to achieve uniformity in diagnosis and treatment., Patients and Methods: From 1994 to 2014 a database of consecutive patients from 3 maxillofacial departments (Academic Medical Center, Amsterdam; VU Medical Center, Amsterdam and Spaarne Gasthuis, Haarlem) with suspected UCH was set up. Patients were referred by orthodontists, dentists, general practitioners or maxillofacial surgeons. Demographic features, bonescan outcomes, laterality, classification and follow-up were noted. Secondarily, all patients were retrospectively diagnosed by one surgeon (JWN), using available documentation. Missing data and follow-up were additionally retrieved from orthodontic offices., Results: 394 asymmetric patients were evaluated. In 309 (78%) patients, the diagnosis UCH was justified and SPECT data were available. The mean age at presentation was 20.3 years (SD ± 7.7, range 9.0-54.5 years). In 48% of the patients, the bonescan was positive. 80% of these patients received surgical treatment, of which 62% were treated with a condylectomy only, 33% were treated with condylectomy plus additive corrective surgery, and 5% underwent corrective surgery only. Of the patient group without positive bonescan 42% of the patients received surgical treatment: 34% condylectomy only, 15% condylectomy plus additive corrective surgery, and 51% corrective surgery only. In total (N = 309) 96 (31%) patients underwent condylectomy as only surgical treatment and 124 (40%) patients received no surgical treatment at all. Treatment could be finalized with orthodontic treatment without further surgery in 64% and 41% respectively. 96 patients were subject to comparison of the classification as noted by the clinician and the author (JWN). In only 72% of the cases, the secondary screening was in agreement with the initial classification., Conclusion: Based on this study not all (active) UCH patients require corrective (orthognathic) surgery. A (transoral) partial condylectomy for active patients is recommended, with a postoperative remodeling period of 6 months with or without orthodontic treatment. Second stage correcting surgery may be necessary upon evaluation, using general orthognathic diagnostic and planning procedures. It appears difficult to classify patients reliably using the available clinical and radiological documentation. Objectivity and quantification in the diagnostic process is necessary: uniformity in documentation and parameters. The attached documentation form and UCH treatment algorithm is recommended., (Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Background: Nowadays, personalized medical devices are frequently used for patients. Due to the manufacturing procedure sterilization is required. How different sterilization methods affect the mechanical behavior of these devices is largely unknown., Materials and Methods: Three poly(methyl methacrylate) (PMMA) based materials (Vertex Self-Curing, Palacos R+G, and NextDent C&B MFH) were sterilized with different sterilization methods: ethylene oxide, hydrogen peroxide gas plasma, autoclavation, and γ-irradiation. Mechanical properties were determined by testing the flexural strength, flexural modulus, fracture toughness, and impact strength., Results: The flexural strength of all materials was significantly higher after γ-irradiation compared to the control and other sterilization methods, as tested in a wet environment. NextDent C&B MFH showed the highest flexural and impact strength, Palacos R+G showed the highest maximum stress intensity factor and total fracture work., Conclusion: Autoclave sterilization is not suitable for the sterilization of PMMA-based materials. Ethylene oxide, hydrogen peroxide gas plasma, and γ-irradiation appear to be suitable techniques to sterilize PMMA-based personalized medical devices., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: Advanced three-dimensional (3D) diagnostics and preoperative planning are the first steps in computer-assisted surgery (CAS). They are an integral part of the workflow, and allow the surgeon to adequately assess the fracture and to perform virtual surgery to find the optimal implant position. The goal of this study was to evaluate the accuracy and predictability of 3D diagnostics and preoperative virtual planning without intraoperative navigation in orbital reconstruction., Methods: In 10 cadaveric heads, 19 complex orbital fractures were created. First, all fractures were reconstructed without preoperative planning (control group) and at a later stage the reconstructions were repeated with the help of preoperative planning. Preformed titanium mesh plates were used for the reconstructions by two experienced oral and maxillofacial surgeons. The preoperative virtual planning was easily accessible for the surgeon during the reconstruction. Computed tomographic scans were obtained before and after creation of the orbital fractures and postoperatively. Using a paired t-test, implant positioning accuracy (translation and rotations) of both groups were evaluated by comparing the planned implant position with the position of the implant on the postoperative scan., Results: Implant position improved significantly (P < 0.05) for translation, yaw and roll in the group with preoperative planning (Table 1). Pitch did not improve significantly (P = 0.78)., Conclusion: The use of 3D diagnostics and preoperative planning without navigation in complex orbital wall fractures has a positive effect on implant position. This is due to a better assessment of the fracture, the possibility of virtual surgery and because the planning can be used as a virtual guide intraoperatively. The surgeon has more control in positioning the implant in relation to the rim and other bony landmarks., (Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Intraoperative navigation is frequently used to assess the position of the implant in orbital reconstruction. Interpretation of the feedback from the navigation system to a three-dimensional position of the implant needs to be done by the surgeon, and feedback is only gathered after the implant has been positioned. An implant-oriented navigation approach is proposed, with real-time intuitive feedback during insertion. A technical framework was set up for implant-oriented navigation, with requirements for planning, implant tracking, and feedback. A dedicated navigation instrument was designed and a software tool was developed in order to meet the technical requirements. An accuracy study was performed to investigate the accuracy of the method in comparison to the regular navigation pointer. A proof of concept was provided. The results showed a translation error of 1.12-1.15mm for implant-oriented navigation with regular registration (pointer 0.71-0.98mm) and 0.81mm with accurate registration (pointer 0.54mm). Rotational error was found to be small (<3°). Quantitative and intuitive qualitative feedback could be provided to the surgeon in real-time during insertion of an orbital implant. Following this proof of concept and accuracy study, the implications for the clinical workflow should be evaluated. An implant-oriented approach may form the foundation for augmented reality or robotic-aided implant insertion., (Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Purpose: Mirroring has been used as a diagnostic tool in orbital wall fractures for many years, but limited research is available proving the assumed symmetry of orbits. The purpose of this study was to evaluate volume and contour differences between orbital cavities in healthy humans., Materials and Methods: In this cross-sectional study, the left and right orbital cavities of a consecutive sample of patients' computed tomograms were measured. Inclusion criteria were patients with no sign of orbital or sinus pathology or fracture. Outcome variables were differences in volume and contour. Descriptive statistics and Student paired t test were used for data analysis of orbital volume and distance maps were used for analysis of orbital contour., Results: The sample was composed of 100 patients with a mean age of 57; 50% were men. The total mean orbital volume was 27.53 ± 3.11 mL. Mean difference between cavities was 0.44 ± 0.31 mL or 1.59% (standard deviation [SD], 1.10%). The orbital contour showed high similarity, with an absolute mean left-versus-right difference of 0.82 mm (SD, 0.23 mm)., Conclusion: The authors hypothesize that the measured differences between right and left orbital volumes and contours are clinically minor. In consequence, the use of mirroring tools as part of preoperative planning in orbital reconstruction is legitimate with the aim of simulating the pre-traumatized anatomy., (Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: The study aim was to investigate variations in the symmetry of the zygomaticomaxillary complex (ZMC) in normal individuals., Method: Computed tomography datasets of 200 individuals without facial fractures were analyzed using a validated three-dimensional analysis technique. The absolute average distance (AD) and 90th percentile distance (NPD) were calculated, representing respectively the overall and maximum symmetry between bilateral ZMCs., Results: The mean AD and NPD of the total study group was 0.9 ± 0.3 mm (95% CI 0.3-2.3) and 1.7 ± 0.5 mm (95% CI 0.5-3.9), respectively. The mean AD and NPD in males were 1.0 ± 0.3 mm (95% CI 0.28-2.34) and 1.9 ± 0.5 mm (95% CI 0.5-3.9) versus 0.8 ± 0.3 mm (95% CI 0.4-1.7) and 1.6 ± 0.5 mm (95% CI 0.8-2.9), respectively, for females. A statistically significant difference between male and female was found for both AD and NPD (p < 0.01). The male population <40 years had a mean AD and NPD of 1.0 ± 0.3 mm and 1.8 ± 0.5 mm, which was not statistically significant when compared with males >40 years., Conclusion: The naturally occurring anatomic variation in ZMC symmetry described in this study is proposed as a benchmark for evaluating the amount of preoperative displacement and postoperative reduction of ZMC in trauma cases., (Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Purpose: This study determined the average distances and angles between anatomic landmarks within the orbit, with an emphasis on localization of the orbital process of the palatine bone. This information will help the surgeon with treatment planning and surgical procedures., Patients and Methods: Four anatomic landmarks were identified retrospectively on computed tomograms of 100 adult Caucasian patients (50 men and 50 women): the top of the infraorbital margin superior to the infraorbital foramen (point A), the top of the orbital process of the palatine bone (point B), the anteriormost bony portion of the superior orbital fissure (point C), and the ventrolateral aspect of the bony entrance of the optic canal (point D). The distances between these points were measured, as were the angle between the medial wall of the orbit and a line connecting points A to D at the level of the optic nerve., Results: The mean distances between the orbital rim (point A) and the orbital process of the palatine bone (point B) were 33.8 mm in men and 32.7 mm in women. Men had markedly larger bony orbits than women; however, women had a larger angle than men for the 2 orbits., Conclusion: Obtaining these measurements preoperatively can enable a safer and more predictable surgical approach to the orbit, which can help lower the risk of damaging important neighboring structures. A preformed reconstruction plate can be manufactured or a standard reconstruction plate can be customized according to these measurements; during reconstruction, they also can help adequately localize the posterior ledge, specifically the orbital process of the palatine bone. These 2 aspects could ensure a more precise reconstruction of the orbital floor., (Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

A novel surgical treatment sequence for secondary orbitozygomatic complex (OZC) reconstruction is described. Orbital reconstruction is performed before OZC repositioning. A surgical plan is made: the affected OZC is virtually osteotomized and aligned with a mirrored model of the unaffected OZC. A patient-specific implant (PSI) is designed for orbital reconstruction. Screw holes from the primary reconstruction are used for fixation. Primary screw hole positions at the repositioned OZC are embedded in the design, to guide OZC repositioning. A second patient-specific design is made for guidance at the zygomaticomaxillary buttress. The workflow was utilized in two patients. The PSI was positioned using navigation feedback. After repositioning of the zygomatic complex, the screw hole positions at the infraorbital rim and zygomaticomaxillary buttress seemed to align perfectly: no screw hole adjustments were necessary. Minor deviations were seen between planned and acquired PSI position; the mean errors between planned and acquired OZC position were 1.5 and 1.2 mm. Orbital reconstruction with a PSI before OZC repositioning ensures true-to-original orbital reconstruction. The use of old screw hole positions enables the PSI to be used as a static guide for OZC repositioning. The combination of static and dynamic guidance increases predictability in secondary OZC reconstruction., (Copyright © 2017. Published by Elsevier Ltd.)

Purpose: Three-dimensional quantification of asymmetry in UCH has not been reported yet, but would be useful for diagnosing and evaluating the degree of deformity in this disease. It enables profound decision-making and timing of surgery. Unilateral condylar hyperplasia (UCH) can subjectively be classified in hemimandibular elongation (HE), hemimandibular hyperplasia (HH) and a combination of these two (hybrid form). The main purpose of this study was to quantify mandibular asymmetry in UCH patients with a reliable and reproducible method. Secondly, it was evaluated whether the existing classification can be confirmed., Materials and Methods: 37 UCH-patients with progressive mandibular asymmetry, supported by a positive bone scan and/or such clinical progression that condylectomy was performed, were included in this retrospective study. A group of healthy subjects, matched for age and gender, was used as the control group. Cone-beam computed tomography (CBCT) scans were imported in Maxilim ® software. Each mandibular half was divided into three skeletal segments (condyle, ramus, and body). Linear and volumetric measurements were calculated for these skeletal units on the affected and unaffected side, for both patients and controls., Results: Significant differences between affected and unaffected sides in the patient group were found in condylar, ramus, and body segments for linear (p < 0.01) as well as for volumetric quantitative measurements (p < 0.0040). A mean linear difference between affected and unaffected sides in the condylar region of the UCH patient group was found of 3.6 mm (sd 2.9) versus 0.2 mm (sd 1.5) in controls. For volumetric measurements there was a mean difference between the left and right condyle of 718 mm 3 (sd 638) in the patient group versus 8 mm 3 (sd 225) difference in the control group. The condyle was the most affected segment. Differences between sides were significantly larger in the patient group than in the control group (p < 0.001). It was not possible to objectify differences between HE and HH., Conclusion: CBCT is a useful and accurate modality for quantification and evaluation of mandibular asymmetry in UCH. It enables objective monitoring. The existing classification in HE and HH could not be confirmed., (Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Objective: The study aim was to validate a new method for measuring zygomaticomaxillary complex (ZMC) symmetry, which can be helpful in analyzing ZMC fractures., Methods: Three-dimensional virtual hard-tissue models were reconstructed from computed tomography (CT) datasets of 26 healthy individuals. Models were mirrored and superimposed. Absolute average distance (AD) and 90th percentile distance (NPD) were used to measure overall and maximal symmetry. The Intraclass Correlation Coefficient (ICC) was calculated to measure interobserver consistency. In order to determine whether this technique is applicable in ZMC fracture cases, 10 CT datasets of individuals with a unilateral ZMC fracture were analyzed., Results: For the unaffected group the mean AD was 0.84 ± 0.29 mm (95% CI 0.72-0.96) and the mean NPD was 1.58 ± 0.43 mm (95% CI 1.41-1.76). The ICC was 0.97 (0.94-0.98 as 95% CI), indicating almost perfect interobserver agreement. In the affected group the mean AD was 2.97 ± 1.76 mm (95% CI 1.71-4.23) and the mean NPD was 6.12 ± 3.42 mm (95% CI 3.67-8.57). The affected group showed near-perfect interobserver agreement with an ICC of 0.996 (0.983-0.999 as 95% CI)., Conclusions: The method presented is an accurate instrument for evaluation of ZMC symmetry, which can be helpful for advanced diagnostics and treatment evaluation., (Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Objective: The best material choice for cranioplasty following craniectomy remains a subject to discussion. Complication rates after cranioplasty tend to be high. Computer-assisted 3-dimensional modelling of polyetheretherketone (PEEK) was recently introduced for cranial reconstruction. The aim of this study was to evaluate patient- and surgery-related characteristics and risk factors that predispose patients to cranioplasty complications., Material and Methods: This retrospective study included a total of 40 cranial PEEK implants in 38 patients, performed at two reference centers in the Netherlands from 2011 to 2014. Complications were registered and patient- and surgery-related data were carefully analysed., Results: The overall complication rate of PEEK cranioplasty was 28%. Complications included infection (13 %), postoperative haematoma (10 %), cerebrospinal fluid leak (2.5 %) and wound-related problems (2.5 %). All postoperative infections required removal of the implant. Nonetheless removed implants could be successfully re-used after re-sterilization., Conclusion: Although overall complication rates after PEEK cranioplasty remain high, outcomes are satisfactory, as our results compare favourably to recent literature reports on cranial vault reconstruction., (Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

An unfavourable and unanticipated pattern of the bilateral sagittal split osteotomy (BSSO) is generally referred to as a 'bad split'. Patient factors predictive of a bad split reported in the literature are controversial. Suggested risk factors are reviewed in this article. A systematic review was undertaken, yielding a total of 30 studies published between 1971 and 2015 reporting the incidence of bad split and patient age, and/or surgical technique employed, and/or the presence of third molars. These included 22 retrospective cohort studies, six prospective cohort studies, one matched-pair analysis, and one case series. Spearman's rank correlation showed a statistically significant but weak correlation between increasing average age and increasing occurrence of bad splits in 18 studies (ρ=0.229; P<0.01). No comparative studies were found that assessed the incidence of bad split among the different splitting techniques. A meta-analysis pooling the effect sizes of seven cohort studies showed no significant difference in the incidence of bad split between cohorts of patients with third molars present and concomitantly removed during surgery, and patients in whom third molars were removed at least 6 months preoperatively (odds ratio 1.16, 95% confidence interval 0.73-1.85, Z=0.64, P=0.52). In summary, there is no robust evidence to date to show that any risk factor influences the incidence of bad split., (Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. 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.)

An unfavourable and unanticipated pattern of the mandibular sagittal split osteotomy is generally referred to as a 'bad split'. Few restorative techniques to manage the situation have been described. In this article, a classification of reported bad split pattern types is proposed and appropriate salvage procedures to manage the different types of undesired fracture are presented. A systematic review was undertaken, yielding a total of 33 studies published between 1971 and 2015. These reported a total of 458 cases of bad splits among 19,527 sagittal ramus osteotomies in 10,271 patients. The total reported incidence of bad split was 2.3% of sagittal splits. The most frequently encountered were buccal plate fractures of the proximal segment (types 1A-F) and lingual fractures of the distal segment (types 2A and 2B). Coronoid fractures (type 3) and condylar neck fractures (type 4) have seldom been reported. The various types of bad split may require different salvage approaches., (Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Introduction: In orbital reconstruction, the optimal location of a predefined implant can be planned preoperatively. Surgical results can be assessed intraoperatively or postoperatively. A novel method for quantifying orbital implant position is introduced. The method measures predictability of implant placement: transformation parameters between planned and resulting implant position are quantified., Methods: The method was tested on 3 human specimen heads. Computed Tomography scans were acquired at baseline with intact orbits (t0), after creation of the defect (t1) and postoperatively after reconstruction of the defect using a preformed implant (t2). Prior to reconstruction, the optimal implant position was planned on the t0 and t1 scans. Postoperatively, the planned and realized implant position were compared. The t0 and t2 scans were fused using iPlan software and the resulting implant was segmented in the fused t2 scan. An implant reference frame was created (Orbital Implant Positioning Frame); the planned implant was transformed to the reference position using an Iterative Closest Point approach. The segmentation of the resulting implant was also registered on the reference position, yielding rotational (pitch, yaw, roll) as well as translational parameters of implant position., Results: Measurement with the Orbital Implant Positioning Frame proved feasible on all three specimen. The positional outcome provided more thorough and accurate insight in resulting implant position than could be gathered from distance measurements alone. Observer-related errors were abolished from the process, since the method is largely automatic., Conclusion: A novel method of quantifying surgical outcome in orbital reconstructive surgery was presented. The presented Orbital Implant Positioning Frame assessed all parameters involved in implant displacement. The method proved to be viable on three human specimen heads. Clinically, the method could provide direct feedback intraoperatively and could improve postoperative evaluation of orbital reconstructive surgery.

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.)

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.)

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.)

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.)

A systematic review on complications in all forms of mandibular distraction osteogenesis (MDO) for acquired deformities was performed. Search terms expressing distraction osteogenesis were used in 'AND' combination with search terms comprising 'mandible' and terms for complication, failure, and morbidity. A search using PubMed (National Library of Medicine, NCBI), EMBASE, and the Cochrane Controlled Trials Register yielded 644 articles published between 1966 and mid October 2013. Three hundred and twenty-one eligible articles were screened in detail. Complications related to MDO in acquired deformities were reported in 105 clinical articles, involving 1332 patients. Treatments included alveolar distraction osteogenesis (ADO), mandibular lengthening, DO in bone grafts, and bi-/trifocal transport disc DO (TDDO) for segmental mandibular defects. A high incidence of complications was seen in MDO for acquired deformities (ADO 44.4%; residual group 43.9%). An index for classifying complications in MDO, based on the impact and further treatment or final results, was used. In the ADO group, soft tissue complications (8.0%), insufficient vector control (7.6%), temporary inferior alveolar nerve (IAN) neurosensory disturbances (6.5%), device-related problems (3.5%), mandible fractures (2.8%), insufficient bone formation (2.5%), and fracture of the transport disc (1.3%) were seen. In the residual group, temporary IAN neurosensory disturbances (13.4%), minor infection (5.3%), DO failure (4.0%), and device-related problems (3.8%) were reported., (Copyright © 2015. Published by Elsevier Ltd.)

Patients with suspected unilateral condylar hyperplasia are often screened radiologically with a panoramic radiograph, but this is not sufficient for routine diagnosis and follow up. We have therefore made a quantitative analysis and evaluation of panoramic radiographs in a large group of patients with the condition. During the period 1994-2011, 132 patients with 113 panoramic radiographs were analysed using a validated method. There was good reproducibility between observers, but the condylar neck and head were the regions reported with least reliability. Although in most patients asymmetry of the condylar head, neck, and ramus was confirmed, the kappa coefficient as an indicator of agreement between two observers was poor (-0.040 to 0.504). Hardly any difference between sides was measured at the gonion angle, and the body appeared to be higher on the affected side in 80% of patients. Panoramic radiographs might be suitable for screening, but are not suitable for the quantitative evaluation, classification, and follow up of patients with unilateral condylar hyperplasia., (Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

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.)

A systematic review of English and non-English language articles on the complications of mandibular distraction osteogenesis (MDO) for patients with congenital deformities was performed, in accordance with the PRISMA statement. Search terms expressing distraction osteogenesis were used in 'AND' combination with search terms comprising 'mandible' and terms for complication, failure, and morbidity. A search using PubMed (National Library of Medicine, NCBI), EMBASE, and the Cochrane Central Register of Controlled Trials yielded 644 articles published between 1966 and mid October 2013. Clinical articles that reported complications related to MDO were included. Finally 81 articles on MDO in congenital deformities were eligible and were screened in detail. Complications including minor infection (6.0%), device-related problems (7.3%), skeletal open bite (2.4%), hypertrophic scar formation (2.1%), facial nerve palsy (1.8%), neurosensory disturbances of the inferior alveolar nerve (1.9%), and (fibrous) non-union (0.7%) were seen. A new index for more detailed classification of complications in MDO is proposed based on six categories that indicate the impact of the complication and its further treatment or final results. The proposed complication index may be a useful tool to classify complications related to MDO., (Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

A systematic review of English and non-English articles on the complications of mandibular distraction osteogenesis (MDO) for patients with developmental deformities was performed, in accordance with the PRISMA statement. Search terms expressing distraction osteogenesis were used in 'AND' combination with search terms comprising 'mandible' and terms for complication, failure, and morbidity. A search using PubMed (National Library of Medicine, NCBI), EMBASE, and Cochrane Controlled Trials Register yielded 644 articles published between 1966 and mid October 2013. Clinical articles that reported complications related to MDO in developmental deformities were included. Two hundred and fifty articles were eligible and were screened in detail. A total of 32 articles reporting the cases of 565 patients were finally included. Patients underwent mandibular lengthening and transverse widening. A total of 211 complications were reported (37.4%); these were classified according to an index that indicates the clinical impact. Inferior alveolar nerve (IAN) neurosensory disturbances, minor infection, device failure, anterior open bite, permanent dental damage, and skeletal relapse were most represented. Complications that resolved spontaneously (type I) were seen in 11.0%, medically or technically manageable complications, without hospitalization, were seen in 10.8% (type II), and permanent complications (type VI) were seen in 9.6%., (Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Unilateral condylar hyperplasia or hyperactivity is a disorder of growth that affects the mandible, and our aim was to visualise the 3-dimensional bony microstructure of resected mandibular condyles of affected patients. We prospectively studied 17 patients with a clinical presentation of progressive mandibular asymmetry and an abnormal single-photon emission computed tomographic (SPECT) scan. All patients were treated by condylectomy to arrest progression. The resected condyles were scanned with micro-CT (18 μm resolution). Rectangular volumes of interest were selected in 4 quadrants (lateromedial and superoinferior) of the trabecular bone of each condyle. Variables of bone architecture (volume fraction, trabecular number, thickness, and separation, degree of mineralisation, and degree of structural anisotrophy) were calculated with routine morphometric software. Eight of the 17 resected condyles showed clear destruction of the subchondral layer of cortical bone. There was a significant superoinferior gradient for all trabecular variables. Mean (SD) bone volume fraction (25.1 (6) %), trabecular number (1.69 (0.26) mm(-1)), trabecular thickness (0.17 (0.03) mm), and degree of mineralisation (695.39 (39.83) mg HA/cm(3)) were higher in the superior region. Trabecular separation (0.6 (0.16) mm) and structural anisotropy (1.84 (0.28)) were higher in the inferior region. The micro-CT analysis showed increased cortical porosity in many of the condyles studied. It also showed a higher bone volume fraction, greater trabecular thickness and trabecular separation, greater trabecular number, and less mineralisation in the condyles of the 17 patients compared with the known architecture of unaffected mandibular condyles., (Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Corrective jaw surgery, for patients with malocclusion and dysgnathia, is primarily performed to rehabilitate oral functions. However, the patients' motivation for orthognathic surgery often seems to be influenced as well by the desire for aesthetic correction of a facial anomaly. Preoperative screening for psychiatric problems such as body dysmorphic disorder is requisite. The majority of orthognathic patients experience a negative influence of their appearance on their psychosocial well-being. In addition, the hope for aesthetic improvement is not seldom an important incentive for visiting an oral and maxillofacial surgeon. In the literature, in addition to a positive effect of corrective jaw surgery on the patient's perceived appearance, an associated improvement in quality of life is described. Correction of a disharmonious face is at least as important to patients as oral function recovery.

Unlabelled: (18)F-fluoride PET is a promising noninvasive method for measuring bone metabolism and bone blood flow. The purpose of this study was to assess the performance of various clinically useful simplified methods by comparing them with full kinetic analysis. In addition, the validity of deriving bone blood flow from K1 of (18)F-fluoride was investigated using (15)O-H2O as a reference., Methods: Twenty-two adults (mean age ± SD, 44.8 ± 25.2 y), including 16 patients scheduled for bone surgery and 6 healthy volunteers, were studied. All patients underwent dynamic (15)O-H2O and (18)F-fluoride scans before surgery. Ten of these patients had serial PET measurements before and at 2 time points after local bone surgery. During all PET scans, arterial blood was monitored continuously. (18)F-fluoride data were analyzed using nonlinear regression (NLR) and several simplified methods (Patlak and standardized uptake value [SUV]). SUV was evaluated for different time intervals after injection and after normalizing to body weight, lean body mass, and body surface area, and simplified measurements were compared with NLR results. In addition, changes in SUV and Patlak-derived fluoride influx rate (Ki) after surgery were compared with corresponding changes in NLR-derived Ki. Finally, (18)F-fluoride K1 was compared with bone blood flow derived from (15)O-H2O data, using the standard single-tissue-compartment model., Results: K1 of (18)F-fluoride correlated with measured blood flow, but the correlation coefficient was relatively low (r = 0.35, P < 0.001). NLR resulted in a mean Ki of 0.0160 ± 0.0122, whereas Patlak analysis, for the interval 10-60 min after injection, resulted in an almost-identical mean Ki of 0.0161 ± 0.0117. The Patlak-derived Ki, for 10-60 min after injection, showed a high correlation with the NLR-derived Ki (r = 0.976). The highest correlation between Ki and lean body mass-normalized SUV was found for the interval 50-60 min (r = 0.958). Finally, changes in SUV correlated significantly with those in Ki (r = 0.97)., Conclusion: The present data support the use of both Patlak and SUV for assessing fluoride kinetics in humans. However, (18)F-fluoride PET has only limited accuracy in monitoring bone blood flow., (© 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

A Class III malocclusion is mainly caused by a hypoplastic maxilla and therefore the treatment is principally aimed at stimulating the growth of the maxilla. Disadvantages of conventional treatment methods are that treatment effects are mainly dentoalveolar rather than skeletal and that there is often an increase in the height of the lowerface. Moreover, patients are not always cooperative about wearing extra-oral appliances. Because of these disadvantages, a new treatment approach has been developed which makes use of skeletal anchoring. In this new technique, called 'bone anchored maxillary protraction, bone anchors are placed on both sides of the maxilla and the mandibula, onto which Class III elastics are attached. The literature shows that good results have been achieved with this method. Disadvantages of this method are that the placement of the bone anchors requires a surgical procedure and that complications, like the loosening or breaking of the anchors, can occur.

Objective: This study assessed the quantitative evaluation of the region of interest (ROI) by mean and maximum pixel counts of single-photon emission computed tomography (SPECT) scans in patients with clinical suspicion of unilateral condylar hyperactivity (UCH); the interobserver reliability and the correlation of condylar activity with patient age was determined., Methods: Two independent observers analyzed 67 bone SPECT scans. Maximum and mean activity values within an ROI on the mandibular condyle were analyzed; a cutoff value of 55% was used to determine the qualitative outcome., Results: Excellent interobserver agreement was seen for both maximum (kappa 1.0) and mean activity analysis (kappa 0.94). Maximum and mean condylar activities were strongly correlated (r > 0.98). Maximum and mean condylar activity of the normal condyle decreased significantly with increasing age., Conclusions: Maximum and mean condylar activity levels were highly correlated in patients with mandibular asymmetry. An excellent interobserver agreement was found with either maximum or mean condylar activity., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Purpose: Objective quantifications of facial asymmetry in patients with Unilateral Condylar Hyperplasia (UCH) have not yet been described in literature. The aim of this study was to objectively quantify soft-tissue asymmetry in patients with UCH and to compare the findings with a control group using a new method., Material and Methods: Thirty 3D photographs of patients diagnosed with UCH were compared with 30 3D photographs of healthy controls. As UCH presents particularly in the mandible, a new method was used to isolate the lower part of the face to evaluate asymmetry of this part separately. The new method was validated by two observers using 3D photographs of five patients and five controls., Results: A significant difference (0.79 mm) between patients and controls whole face asymmetry was found. Intra- and inter-observer differences of 0.011 mm (-0.034-0.011) and 0.017 mm (-0.007-0.042) respectively were found. These differences are irrelevant in clinical practice., Conclusion: After objective quantification, a significant difference was identified in soft-tissue asymmetry between patients with UCH and controls. The method used to isolate mandibular asymmetry was found to be valid and a suitable tool to evaluate facial asymmetry.

Unilateral condylar hyperactivity is a growth disorder which is characterised by a progressive asymmetry in the mandibula and in some cases also secondarily in the maxilla. Various forms are hemimandibular hyperplasia, hemimandibular elongation and a hybridform. In deciding on a plan of treatment, it is important to determine whether there is a question of continuous and/or excessive condylar activity, possibly with the help of a skeletal scintigraphy.

With ossification of the stylohyoid ligament a diverse spectrum of complaints are possible. A conclusive explanation for the appearance of this ossification has so far not been found. Since treatment is not, in principle, necessary, a policy of observation is often preferred. If complaints persist, physiotherapy, anti-inflammatory medication or surgical treatment can be considered.

The aims of this study were to compare measurements on three-dimensional (3D) models of human skulls derived from two different cone beam CT scanners (CBCT) and to evaluate if the used hardware can influence the performed measurements. CBCT scans of 40 dry human skulls with both the i-CAT and the Iluma cone beam CT scanners were made. From the CBCT scans, 3D models were constructed. One operator identified 19 landmarks five times on both types of 3D models with a time interval of 1 week. Intra-observer reliability was high for most measurements. There was a statistically significant and clinically relevant difference for some measurements between constructed 3D models of the same skull from the two different CBCT devices. Used hardware for scanning might influence the measurements performed. This means that care should be taken when interpreting measurements made on CBCT 3D models derived from different CBCT devices.

Purpose: Transpalatal distraction osteogenesis is a bone-borne technique to expand the maxilla and has become a routine method in treating patients with transverse maxillary hypoplasia. Limited reports concerning treatment difficulties have been published. The purpose of this study was to investigate and categorize the short- and middle-term incidence of peri- and postoperative difficulties (categorized by the classification of Paley in problems, obstacles, and complications). The signs of adverse dental and periodontal effects were established at least 1 year after removal of the distractor., Patients and Methods: A total of 73 patients (27 male, 46 female; mean age: 28 years; range: 9-59) that underwent bone-borne SARPE in 3 centers were retrospectively investigated. Clinical follow-up was performed in 63 patients after an average period of 23.9 months (range: 6-63 months)., Results: Twenty-seven problems (mainly appliance related), 10 obstacles (appliance-related and asymmetric maxillary expansion), and 1 complication (premature loss of the TPD-module, due to lack of space, in a cleft patient) occurred. Clinical examination showed minimal periodontal damage (gingival recession on 15 sites and pocket depths 4-5 mm in 11 sites). In 28.6% of the incisors radiographic signs of external apical root resorption were seen., Conclusion: Bone-borne SARPE is a reliable technique with predictable outcomes. These results suggest that bone-borne SARPE is associated with a low incidence of dental and periodontal damage. Nevertheless, further research, preferably in randomized controlled design, is needed to evaluate the long-term effects and stability., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

A 10-year-old female patient with a fibula transplant in her left hemimandible due to ameloblastoma treatment was referred for combined orthodontic and surgical planning and treatment to observe and prevent expected asymmetric facial development and malocclusion, because the premolars and molars on the left side of the mandible were missing. The patient had an Angle Class II malocclusion and arch length discrepancy in the upper jaw. The two second premolars in the maxilla were transplanted into the neomandible to create occlusion on the left side and retention for orthodontic treatment. Clinical and radiological examination 3 months postoperatively showed good integration of both premolars without pocket formation. After 4 months, active orthodontic treatment with fixed appliances was started to create sufficient arch space in the upper jaw for both canines to erupt and to extrude and for the transplanted premolars in the lower jaw to rotate and align into the planned positions. This case report demonstrates that autotransplantation of premolars into a fibula transplant can be a successful dental rehabilitation procedure., (Copyright © 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Bone scan analyses and clinical assessment are used to diagnose unilateral condylar hyperactivity (UCH). This review compares the diagnostic accuracy of planar and SPECT bone scans. Studies diagnosing patients with possible UCH using bone scans, published between 1968 and 2008, were included in this review. Of 15 articles that met the inclusion criteria, 7 presented results in sufficient detail to calculate index test characteristics. Three control studies show that the difference in uptake values of the left and right condylar regions in the normal population does not exceed 10%. The pooled sensitivity of the planar bone scan (n=130) was 0.71 (95% confidence interval: 0.57-0.82), which was significantly lower (p=0.04) than that of the bone SPECT technique (n=88), which was 0.90 (0.79-0.97). The pooled specificity of the SPECT scan was 0.95 (0.82-0.99), which did not significantly differ (p=0.58) from that of the planar scan (0.92 (0.83-0.97)). Future studies should include a diagnostic analysis of the data, including two-by-two contingency tables, so the accuracy of the diagnostic test may be evaluated. Bone scans are best performed using SPECT, conducting a quantitative analysis by calculating the percentile differences between the left and right condylar regions., (Copyright © 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

In the treatment of patients with an oro-facial anomaly the functioning of the masticatory system and aesthetic aspects play a role. Recently, the software programme 'Facial Harmony', which analyzes the soft tissue contour of the face, appeared. Using this programme, a research project was carried out to find out if the result of the surgical treatment of 40 patients with an oro-facial anomaly satisfied the,facial harmony requirements. Only 65% of the treatment results met the requirements. It was especially the patients who had been treated for mandibular deficiency with mandibular and horizontal lines meeting at a wide angle who showed no facial harmony. Only 30% of those patients demonstrated facial harmony postoperatively. If the surgical treatment had been completed by a genioplasty, this percentage would very probably have risen to 85.

Sensory impairment of the inferior alveolar nerve in the region undergoing treatment is an unfortunate complication after the surgical removal of a mandibular third molar. Coronectomy is a treatment in which only the crown portion and part of the roots of the tooth are removed. The apical portion of the roots is deliberately left in place in order to avoid damage to the nerve. In a group of 34 patients, a total of 38 coronectomies was carried out, because these patients had a radiologically determined increased risk of inferior alveolar nerve damage in case of surgical removal. The mean follow-up period was 16.7 months, ranging from 3-62 months. None of the patients experienced sensory impairment of the alveolar nerve in the region under treatment. In the case of 3 patients, roots left in place appeared to cause complaints and were removed after all. The conclusion of the study was that coronectomy seems a useful and safe treatment option.

Purpose: The purpose of this study was to assess temporomandibular function after condylectomy because of unilateral condylar hyperactivity (UCH) by means of standardized diagnostic criteria. The results were compared with those obtained in a control group., Patients and Methods: In this study, 33 patients with UCH who underwent condylectomy and 31 controls matched for age and gender filled out a history questionnaire and underwent a clinical examination as part of the research diagnostic criteria for temporomandibular disorders. Data analysis was performed by use of the Fisher exact test for 2-by-2 tables., Results: Patients and controls did not differ significantly regarding myofacial pain (P = .131), disc displacement (P = .516), and depression (P = .34). The groups differed significantly concerning arthralgia, osteoarthritis, and osteoarthrosis (P = .003), as well as pain with low disability (P = .022)., Conclusions: In patients with UCH who underwent condylectomy because of progressive mandibular asymmetry, more joint-related temporomandibular problems as well as more postoperative pain developed when compared with age- and gender-matched controls. However, these problems did not lead to more severe disabilities in daily life., (Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To perform a histopathologic analysis of condyles that were resected because of unilateral condylar hyperactivity and compare the results of the bone scan with the histopathologic findings., Patients and Methods: A total of 47 resected condyles were histopathologically examined. In 29 cases, a single photon emission computed tomography (SPECT) bone scan was available. For all condylar specimens, a standardized histologic scoring system was used to assess the number of cartilage islands and the thickness of the cartilage layer. The SPECT scans were analyzed by calculating the difference in bone activity between the hyperactive and contralateral condyles., Results: The number of cartilage islands was highly variable, ranging from almost absent in 37% of the patients to abundant in 35%. Furthermore, the relative thickness of the cartilage layer exhibited considerable variation, from less than one quarter of the total thickness of the condylar articular layer in 22% of the patients to one half of the total thickness in 35%. We found no significant relationship between the number of cartilage islands and bone activity using SPECT (P = .11) or between the relative thickness of the cartilage layer and bone activity using SPECT (P = .82)., Conclusions: Unilateral condylar bone growth can occur without large numbers of cartilage islands and without abundant cartilage formation. The bone activity measured by bone scintigraphy was not related to the histologic results. The histopathologic findings of resected condyles in unilateral condylar hyperactivity cannot, therefore, be used as a reference standard. Nevertheless, histopathologic examination should always be performed to rule out other diseases.

This study aimed to compare different analytical methods and identify the optimal analysis method to distinguish patients with unilateral condylar hyperactivity (UCH) from those with inactive condyles. Single-photon emission computed tomography (SPECT) scans of patients with progressive and nonprogressive mandibular asymmetry (each group, n=26), were analyzed using the region of interest technique. Sensitivity, specificity and receiver operating characteristic (ROC) curves were calculated for the different analytic methods. The ROC curve illustrates that UCH can be diagnosed significantly better by determining the percentile bone activity in both condyles. The area under the curve (AUC) of the percentile comparison between the affected and contralateral condyles was 0.93+/-0.04, that for the condyle/clivus ratio was 0.75+/-0.07 and for the condyle/cervical spine (CS) ratio 0.57+/-0.08. Sensitivity for the condyle/clivus ratio was 65% and specificity 61%. Sensitivity for the condyle/CS ratio was 85% and specificity 31%. For the percentile difference of the condyles, sensitivity and specificity were 88%. For UCH patients, direct comparison of bone activity between the affected and contralateral condyle in SPECT scans is the analysis method of choice. Comparison of condylar bone activity to reference bone activity does not have additional value in the diagnosis of UCH.

Neurosensory disturbance (NSD) of the inferior alveolar nerve (IAN) is the most common complication after bilateral sagittal split osteotomy (BSSO) and distraction osteogenesis (DO) of the retrognathic mandible. It is suggested that the risk is lower after DO than after BSSO. This retrospective study compared both techniques with regard to long-lasting NSD and overall patient satisfaction. 91 patients (representing 182 IANs) were included, they completed a questionnaire and underwent an objective neurosensory test. In the BSSO-group (90 nerves), long-lasting NSD was reported in 27 cases (30%) versus 21 cases (23%) in the DO group (92 nerves). In 39 cases (24 BSSO, 15 DO) the long-lasting NSD was reported in the lower lip, the chin or both. Of these cases, 9 (5 BSSO, 4 DO) were objectively tested positive. The overall prevalence was 8% in the BSSO group and 10% in the DO group. There was no significant difference in subjectively reported and objectively measured NSD between the groups. In this study patients seemed to over-report the NSD compared with the objective findings. For both procedures, overall patient satisfaction was high.

Purpose: Informed consent forms an important part of treatment, especially in the case of elective treatment. The aim of this survey was to establish how much patients can recall of the information given during an informed consent interview before orthognathic surgery. During the consultation, attention was given to all aspects of the treatment. However, because of "insurance-related factors," the need for treatment because of functional reasons was stressed over esthetics. The recall of information given during an informed consent interview before orthognathic surgery was measured using a questionnaire., Materials and Methods: Patients with a mandibular deficiency with a low mandibular plane angle were questioned after an informed consent interview regarding surgical orthodontic treatment., Results: Esthetics were more frequently and functional problems were less frequently recalled as the reason for operation than was expected. The risk of a change in the sensation of the lower lip by surgery was frequently recalled as a reason to refrain from the operation. The overall recall rate of the possible risks and complications of orthodontic surgery was 40%., Conclusions: No reports were found of comparable research on the preoperative recall after consultation before surgical orthodontic surgery. The aspects of communication that can improve recall must be clarified. A recall rate of 100% seems a utopia, although an arbitrary line is needed to determine the quality of an informed consent interview.

Purpose: The purpose of this study was to assess bone growth and blood flow in the condylar region in patients with unilateral condylar hyperactivity (UCH) by use of positron emission tomography (PET)., Patients and Methods: This prospective study included 7 patients with UCH and a control group of 6 volunteers. In addition to normal clinical investigations, labeled fluoride ((18)F(-)) and oxygen 15-labeled water (H(2)(15)O) PET scans were performed., Results: In control subjects the net rate of fluoride influx, representing bone metabolism, was similar for left and right condylar sides. Interestingly, this was not significantly different from the affected condyles in UCH patients. Rather, the net rate of fluoride influx on the contralateral side of UCH patients was reduced significantly compared with the affected side (P= .02) and control subjects (P= .004). The mean blood flow on the left and right condylar sides in control subjects was not significantly different. The same was true for the hyperactive and contralateral condyles of UCH patients. Blood flow in the condylar region in UCH patients was similar to that in the control group., Conclusions: There was no evidence of an abnormally high rate of bone growth in the affected condylar region in UCH patients. Instead, the rate of bone growth appeared to be reduced in the contralateral condylar region. These PET results are in contrast to the characteristic clinical picture of UCH patients and suggest the possibility of subgroups in patients with a mandibular asymmetry caused by UCH. Furthermore, no evidence of hypervascularization of the condylar region in UCH patients was found.

Objective: A comparison is made of single photon emission computed tomography (SPECT) and planar bone scintigraphy in the diagnosis of patients with suspected unilateral condylar hyperactivity (UCH)., Study Design: The subjects comprised 56 patients with suspected UCH who underwent SPECT and regular planar bone scans. Accuracy of SPECT and planar scintigraphy were compared using left-right condylar activity., Results: Of the 56 patients, 29 were diagnosed with active UCH and 27 without UCH. The mean relative activity of the hyperactive condylar region in the planar scans was 53.5% (SD +/- 2.3%), which was significantly higher in the SPECT scan with a mean value of 60.5% (SD +/- 5.4%), P < .005 (t = 8.951). Receiver operating curves (ROC) were clearly in favor of SPECT over the planar bone scan. The area under the curve (AUC) of the planar ROC was 0.87 +/- 0.049 while that of the SPECT ROC was 0.97 +/- 0.024. The optimal cut-off value for planar scanning was 52%, yielding a sensitivity of 67% and a specificity of 85%. For SPECT scanning, the optimal cut-off was 56%, resulting in a sensitivity of 93% and a specificity of 96%., Conclusions: It can be concluded that in patients with a clinically suspected active UCH, SPECT scanning is the preferred diagnostic tool rather than planar bone scanning. However, treatment planning should be done in combination with clinical assessment of progressive mandibular asymmetry as well as taking into account the patient history.