The effect of a modified reverse headgear force applied with a facebow on the dentofacial structures.
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The purpose of this study was to evaluate the effects of a modified reverse headgear force applied with a facebow on the dentofacial structures of patients with skeletal Class III malocclusions characterized by maxillary retrognathism. Thirty individuals before the pubertal peak and in the mixed dentition were selected. Fifteen subjects (seven males, eight females, mean age 9.2 years) who formed the treatment group were compared with a control group comprising seven males and eight females (mean age 8.6 years). Maxillary deficiency and negative overjet were noted in all individuals included in the treatment and control groups. The combination of a full coverage maxillary removable appliance and an embedded facebow was used for treatment. The outer arms of the facebow were bent to deliver the force through the approximate centre of resistance of the maxilla. Extra-oral elastics extended from the reverse headgear to the outer arms of the facebow. Statistical analysis indicated significant changes in angles SNA, NV-A, SV-ANS, SV-PNS and PP measurements, suggesting that the maxilla moved anteriorly. There was, however, no statistically significant difference in SN-MP, SN-PP and MP-PP measurements between the treatment and control groups. These results suggest that there was no maxillary or mandibular rotation, but that the molars moved mesially in the protraction group. The U6-PP(V) dimension did not display significant differences between the pre- and post-treatment measurements in the treated group. Anterior movement of the maxilla was obtained without rotation of the jaws and upper and lower maxillary heights were unaffected. (+info)
Three-dimensional computational reconstruction of lateral skull base with plastinated slices.
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The goals of this study were to build the 3D reconstructed model of lateral skull base and to explore the spatial relationships of the important structures for providing the morphological basis for lateral skull base surgery and clinical image diagnosis. Blocks with edges of about 80 mm containing the lateral skull base region and adjacent structures were sawn out from both sides of the heads and sectioned on transverse plane at a thickness of 700 microm using a plastination technique. On an SGI workstation, a Contours-Marching cubes algorithm was selected to reconstruct the 3D model of the lateral skull base. Accurate alignment of the structures in the serial macroscopic sections was obtained by the employment of the plastination technique. The quality of the reconstructed images was distinct and perfect, specifically, the spatial positions and complicated adjacent relationships of various structures of the lateral skull base can be shown in direct viewing when they are displayed in background of the cranial bony substance. The time spent in displaying or rotating one image including 50 sections was 1.5 sec; all reconstructed structures can be represented individually or jointly and rotated in any plane. The plastination technique and computer-aided 3D reconstruction have an obvious advantage in the study of the complex anatomy of the lateral skull base. Plastination technique provides cross-section images of a higher resolution than those obtained from CT scanning. The computerized 3D reconstruction is important in studying the spatial anatomy of the lateral skull base and can serve as a standard for models created with other techniques. (+info)
Variation in the cranial base orientation and facial skeleton in dry skulls sampled from three major populations.
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The aim of this study was to analyse the effects of cranial base orientation on the morphology of the craniofacial system in human populations. Three geographically distant populations from Europe (72), Africa (48) and Asia (24) were chosen. Five angular and two linear variables from the cranial base component and six angular and six linear variables from the facial component based on two reference lines of the vertical posterior maxillary and Frankfort horizontal planes were measured. The European sample presented dolichofacial individuals with a larger face height and a smaller face depth derived from a raised cranial base and facial cranium orientation which tended to be similar to the Asian sample. The African sample presented brachyfacial individuals with a reduced face height and a larger face depth as a result of a lowered cranial base and facial cranium orientation. The Asian sample presented dolichofacial individuals with a larger face height and depth due to a raised cranial base and facial cranium orientation. The findings of this study suggest that cranial base orientation and posterior cranial base length appear to be valid discriminating factors between different human populations. (+info)
A 30-year-old man presented with a 2-year history of intermittent headache. No neurological deficit was detected. Computed tomography (CT) and magnetic resonance imaging showed a tumor with a diameter of 2.5 cm in the left anterior skull base associated with bone scalloping on three-dimensional CT. Angiography showed a hypovascular tumor. Craniotomy demonstrated a tumor in the region of the left olfactory groove attached to the anterior part of the cribriform plate. The histological diagnosis was schwannoma. Schwannoma arising from near the olfactory groove is rare, with only 13 other cases reported. The precise origin of these tumors is not well understood, but the tumor in this case probably arose from the fila olfactoria, because the olfactory bulb was involved in the tumor, whereas the olfactory tract remained intact. (+info)
Craniofacial skeletal and soft tissue morphology in Icelandic adults.
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The purpose of the study was to describe the craniofacial characteristics of Icelandic adults on lateral skull cephalograms. The material consisted of 155 (47.8%) males and 169 (52.5%) females. The mean ages were 35.5 and 34.2 years, respectively. Twenty-two skeletal reference points and 11 soft tissue points were digitized and processed by standard methods with the Dentofacial Planner computer software program. The 45 variables calculated were both angular and linear. Two-sample t-tests were used to study the differences between sexes. Mandibular prognathism was significantly greater in males (P < or = 0.05), but the inclination of both the upper and lower jaws was greater in females (P < or = 0.01). Linear measurements were usually larger for males. The lips were less protrusive in males (P < or = 0.01), but the thickness was greater compared with females (P < or = 0.001). The nose was significantly more protrusive in males (P < or = 0.001). When the Icelandic sample was compared with closely related ethnic groups, such as the Swedes and the Danes, it was interesting to note that the Icelanders seem to be more like the Swedes than the Danes. (+info)
Delineation of lateral tentorial sinus with contrast-enhanced MR imaging and its surgical implications.
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BACKGROUND AND PURPOSE: The lateral tentorial sinus (LTS) has not been well described in the imaging literature. The aim of this study was to investigate the value of MR imaging in assessing the LTS, which may provide guidance for preoperative planning. METHODS: Fifty-five adult patients underwent MR imaging of the brain. Four neuroradiologists evaluated the studies for delineation of the LTS and its branches. Presence of arachnoid granulation and dominance of the venous drainage also were reported. RESULTS: An LTS was detected in 104 of 110 lobes. The LTS in each lobe was classified as type I (candelabra) in 30 (28.8%), type II (independent veins) in 22 (21.1%), and type III (venous lakes) in 37 (35.5%); in 15 (14.4%) of the lobes, the LTS was indeterminate. LTS branches were inconsistently detected, with the exception of the vein of Labbe (VL). Five of eight branches were seen in approximately half of the cases. The VL was identified in 94 (85.4%) lobes. Among these, 53 (56.4%) were draining into the LTS and 22 (23.4%) into the transverse sinus; in 19 (20.2%) cases, the terminal portion was not visualized. The right transverse sinus was dominant in 19 (34.5%) patients and the left in 18 (32.7%); codomination was present in 18 (32.7%) cases. At least one arachnoid granulation was seen in the transverse sinus in 27 (49.1%) patients. CONCLUSION: In many instances, the LTS and VL drainage patterns were well delineated on routine MR images. For selected cases, this information may be crucial during lateral skull base surgery to avoid venous infarct. (+info)
The treatment of complex dural arteriovenous fistulae through cranial base techniques.
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INTRODUCTION: The endovascular modality of treatment is the preferred treatment modality for DAVF. In some circumstances, successful obliteration may not be possible by endovascular means, and such cases may require a direct surgical treatment. The authors report on their experience with the use of cranial base approaches in the treatment of deep and complex DAVF. MATERIALS AND METHODS: Nine patients were treated between 1992 and 2003. There were six females and three males. Four patients presented with intracerebral hemorrhage, two with progressive myelopathy, two with tinnitus, and one with incapacitating chronic seizures. Four DAVF were tentorial, two transverse sigmoid, one craniocervical, one straight sinus, and one sphenoparietal. Endovascular embolization was attempted and unsuccessful in four cases, and was successful only as an adjunct to surgery in four others. All patients required the use of cranial base approaches to disconnect the fistula or resect the nidus. RESULTS: Complete obliteration of the fistula was possible in all cases. Six-month follow-up results were obtained on seven patients where there was no evidence of recurrence. One postoperative temporal-lobe hematoma required surgical evacuation. One patient died two years postoperatively from an unrelated cause. CONCLUSION: This retrospective study demonstrates that complex DAVF can be successfully treated with the assistance of cranial base techniques. (+info)
A case of Antley-Bixler syndrome with severe skeletal Cl. III malocclusion.
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Antley-Bixler syndrome is a disorder characterized by craniosynostosis, midface hypoplasia, choana blockade, and radiohumeral synostosis. However, the features of occlusion remain unclear. In this paper, we report a case of Antley-Bixler syndrome, a 7-year-old boy, from the viewpoint of orthodontics. From lateral cephalometric head film analysis, remarkable retardation of the anterior subcranial base, infraorbitale, and maxilla were notable, as was vertical growth restriction of the maxilla. The choana blockade tendency was also recognized. Moreover, although reverse occlusion was present, a mandibular retrognathic tendency was also present, and a short ramus mandible, remarkable mandibular vertical growth pattern, and skeletal open bite were present. In the dentition, two of the lower incisors were missing, and the present lower incisors were large. Maxillary and mandibular first molars were delayed in eruption. For treatment, the solutions to such remarkable skeletal problems were limited by the insufficiency of recovery of cranial formation after the operation. We planned a non-surgical treatment to expand the maxilla. It will be necessary to continually consider the treatment of his malocclusion as he continues to grow. (+info)