Multimodality management of a case of primary osteogenic sarcoma of the zygoma. (1/83)

Craniofacial osteogenic sarcomas are rare primary malignant bone tumors and very few cases involving zygomatic bone were reported in literature. We present our experience of multimodality management of a case of primary osteogenic sarcoma of zygoma. Wide radical excision of the tumor including the parotid gland was done followed by three cycles of adjuvant chemotherapy and fifty Gy of external radiotherapy. The patient is disease-free at two years follow-up. Till 1970s, craniofacial osteogenic sarcomas were managed mainly by radical surgery with a high local failure rate. With the advances made in the field of radiotherapy and chemotherapy, multimodality therapy is playing a major role in the treatment of these aggressive tumors with better overall and disease-free survival.  (+info)

Three-dimensional loading and growth of the zygomatic arch. (2/83)

Despite a number of previous biomechanical studies on the zygomatic arch, unanswered questions remain about its three-dimensional loading and growth. Using young miniature swine, we have for the first time recorded strains from both the medial and lateral aspects of the squamosal bone during mastication and masseter muscle stimulation. Strains from the zygomatic bone flange and zygomatic arch growth data were also obtained from the same animals. A second study on a younger group of animals examined the growth of the zygomatic flange following partial removal of the masseter. Strain data indicated that the squamosal bone is bent out-of-plane and that this pattern of loading is quite different from that of the adjacent zygomatic bone, which experiences much lower strains with little evidence of out-of-plane bending. Surprisingly, strains were higher in the zygomatic flange during contralateral chews and contralateral masseter stimulations than during ipsilateral chews/stimulations. These strains proved to arise from movement of the condyle, explaining why partial removal of the masseter had little effect on the growth of the flange. Other growth results indicated an approximately threefold greater rate of subperiosteal deposition on the lateral surface of the squamosal bone than on the zygomatic bone. This difference in growth rate is attributed to the presence of sutures that contribute to the lateral displacement of the zygomatic bone but not the squamosal bone. This explanation does not exclude the possibility that the rapid apposition on the lateral squamosal surface is regulated by the high surface strains that result from out-of-plane bending.  (+info)

Morphological castes in a vertebrate. (3/83)

Morphological specialization for a specific role has, until now, been assumed to be restricted to social invertebrates. Herein we show that complete physical dimorphism has evolved between reproductives and helpers in the eusocial naked mole-rat. Dimorphism is a consequence of the lumbar vertebrae lengthening after the onset of reproduction in females. This is the only known example of morphological castes in a vertebrate and is distinct from continuous size variation between breeders and helpers in other species of cooperatively breeding vertebrates. The evolution of castes in a mammal and insects represents a striking example of convergent evolution for enhanced fecundity in societies characterized by high reproductive skew. Similarities in the selective environment between naked mole-rats and eusocial insect species highlight the selective conditions under which queen/worker castes are predicted to evolve in animal societies.  (+info)

Bilateral fronto-orbito-zygomatic craniotomy--a combined extended frontal and orbitozygomatic approach. (4/83)

In extensive skull base lesions involving the spheno-ethmoido-clival region and extending into both the cavernous sinuses and infratemporal regions, a combination of approaches is usually required, either in the same operation or at a second stage. The bilateral fronto-orbito-zygomatic craniotomy described in this report is a combination of an extended frontal approach and fronto-orbito-zygomatic craniotomy. This gives a wide exposure of the spheno-ethmoido-clival regions of both the cavernous sinuses and both the infratemporal regions. The exposure is thus greatly improved with minimal frontal lobe retraction. The single bone piece can be speedily replaced obviating the need for a complicated reconstruction technique and gives a superior cosmetic result. The operative technique is described in detail.  (+info)

Multiple intracranial aneurysms associated with branchio-oto-dysplasia. (5/83)

Branchio-oto-dysplasia is characterized by abnormalities of embryonic branchial arch system and deafness inherited as autosomal dominant with variable gene expression. We present a rare case of multiple intracranial aneurysms associated with branchio-oto-dysplasia. A 40-yr-old man with severe headache presented as spontaneous subarachnoid hemorrhage on brain computed tomographic scan. The patient also manifested clinical features of branchio-oto-dysplasia and right hemifacial hypoplasia. Carotid angiogram confirmed an aneurysm in the anterior communicating artery. Intraoperative findings demonstrated multiple aneurysms in the anterior communicating artery and in the left posterior communicating artery, which were clipped successfully. Postoperative course was uneventful. This condition has not been reported previously. We also reviewed literatures to discuss whether the intracranial aneurysm was as a coincidental finding or a part of this malformation.  (+info)

Intraosseous hemangioma of the zygoma: CT and MR findings. (6/83)

Intraosseous hemangiomas are uncommon, constituting less than 1% of all osseous tumors. The most frequent sites are the calvaria and the vertebral column. Involvement of the facial bones is rare, and occurs most commonly in the maxilla, mandible, and nasal bones. Only 20 cases of zygomatic involvement have been reported in the English-language literature. We report a case of an intraosseous hemangioma of the zygoma documented by CT and MR studies.  (+info)

Single flap fronto-temporo-orbito-zygomatic craniotomy for skull base lesions. (7/83)

Surgery was performed, through single flap fronto-temporo-orbito-zygomatic approach in 22 patients with skull base lesions. In two of these patients, this approach was combined with a transpetrosal approach. The pathological spectrum consisted of trigeminal neurofibromas (5), spheno-orbital meningiomas (4), carotico-ophthalmic aneurysms (4), basilar top aneurysms (2), cavernous sinus haemangiomas (2), invasive pituitary tumours (2) and one patient each of metastatic adenocarcinoma of the cavernous sinus, transcranial fungal granuloma and tubercular granuloma of the cavernous sinus. Of the 14 tumours, 10 were excised totally/near totally while a subtotal excision was achieved in four. Removal of the anterior clinoid process facilitated the clipping of all the carotico-ophthalmic aneurysms. One basilar top aneurysm was wrapped and the other clipped. One patient of fungal granuloma died of fungal meningitis and one patient of basilar top aneurysm expired as a result of thalamic infarct. The advantages of this approach included excellent exposure of the skull base lesions, making the dissection distance shorter and wider, minimal brain retraction and easy replacement of the single bone flap.  (+info)

Measurement of lateral loads exerted on the maxillofacial region by habitual postures. (8/83)

Lateral loads exerted on the maxillofacial region by habitual postures and habits may cause lateral shift or deformity of the mandible. These loads were measured with a desktop dynamic-strain gauge (DPM-600, Kyowa Co.) connected to a small, highly sensitive pressure sensor (PSL-A type, Kyowa Co.), and recorded with an oscillographic recorder (RDM-100A, Kyowa Co.). Measurements were taken with a pressure sensor embedded in silicone impression material placed in a vinyl chloride resin bag, on which pressures were applied. A preliminary study was conducted to obtain a proportional constant and a conversion formula for load calculation. The subsequent main study included 20 healthy male volunteers for load measurement in 12 positions. The mean load exerted on the mandible was 43.7 N when the subjects lay face down and approximately 20 N when they sat resting the lateral part of the chin on the hand, indicating that these loads are greater than regular orthodontic forces.  (+info)