ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

During the last decade, rigid internal fixation with miniplates and screws has gained widespread acceptance in the correction of both congenital and acquired craniomaxillofacial deformities. Recent studies have proposed that the currently employed metallic plates and screws may require removal because of potential facial growth restriction in growing children. Others have reported bone resorption under the plate due to stress shielding, infection, extrusion, and palpability in regions where there is minimal tissue coverage. Because these implants are radiopaque, they generate significant artifacts that interfere with radiological studies and with radiation therapy in patients undergoing treatment for malignancies. There is no question that the use of a biodegradable plating system would eliminate each of these potential or real problems, because stability is necessary only for a reasonably short period until the fracture segments have become united.We report the initial phase of a long-term study examining various materials that will be available for fabrication of a biodegradable plate and screw system. We evaluated a commercially developed biodegradable plate and screw system to treat zygomatic arch fractures in a rabbit model. Fractures were surgically created at the midpoint of each zygomatic arch. The experimental animals were then divided into three equal groups. Fractures in the first group were permitted to heal without any form of stabilization. In the second group, segments were secured with standard titanium plates and screws. Biodegradable plates and screws were employed for stabilization in the experimental group. Animals were then killed, and radiographs were obtained at 2, 4, 6, and 8 weeks. Zygomatic complexes were removed en bloc, and routine hematoxylin and eosin slides were obtained for light microscopy. Without fixation, fracture segments became significantly displaced. Findings were almost identical in the two treatment groups. This biodegradable system appears to have promise in the care of patients with maxillofacial trauma of the midface.

ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

A study was undertaken to evaluate the effects of nerve growth factor (NGF), which had previously demonstrated bone formation around mandibular nerve regenerates, on resorption of onlay bone grafts to the rabbit skull. Iliac grafts were onlayed on the parietal bone bilaterally and immobilized with wire ligatures in 15 animals. NGF and a control solution were introduced into the grafts through subcutaneous osmotic pumps. After 60 days, graft survival was compared by weights, histology, and fluorochrome labels. NGF-treated grafts were characterized by an average of 88.4% weight retention, preservation of the outer cortical plate with firm fixation to the underlying calvarium, and fluorescent labels localized to the inner cortex. Conversely, control grafts had an average weight retention of 42.8% (p< 0.01), nearly complete outer cortical plate loss with increased mobility of the residual inner cortex, and a lack of fluorescence in any part of the grafts. Despite the incongruous name, NGF exhibited a beneficial effect on onlay bone graft volume maintenance in this study. Although the mechanism and the long-term effects are unknown, inhibition of graft resorption rather than enhancement of bone formation is suggested.

ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Eighteen adult patients with hemifacial microsomia were treated with a combination of skeletal and augmentation surgery. Three typical cases are presented. In principle, skeletal and augmentation surgery have recently been performed in combination in a single stage. Groin flaps and scapular or scapular ostocutaneous flaps have mainly been employed for augmentation surgery.

ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Discourse features of 10 mothers of language-normal preschool children with repaired cleft palates were examined. Mothers had been provided training in infant stimulation. Fifty-six percent of the communication initiations within the mother-child dyads were made by the mothers. That level of responsibility for continuity of communication resembles the percentage of discourse initiation reported for mothers of language-normal children without orofacial clefts. All categories of utterance types were used by the subjects; a predominance was found among attention-getters and indirect directives. Distribution of discourse features appears to differ from that reported for mothers of both language-normal and language-impaired children who do not have orofacial clefts.

ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1992

数据来源: OVID