ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Regulation of programmed cell death (apoptosis) is crucial for normal development and growth, both prenatally and postnatally. If its role during normal embryogenesis of a given structure is established, a number of related congenital disorders can be explained by a (local) deregulation of apoptosis. In this study, apoptotic cell death patterns during normal development of the murine coronal suture were investigated. Detection of apoptotic cells was undertaken by labeling with Annexin V. Results showed apoptosis occurring at the same time and place as suture initiation. Apoptotic cells are located along the entire established part of the suture and its developing part. Because apoptosis is shown to be highly associated with sutural genesis, the theory of craniosynostosis being the equivalent of deregulation at this locus seems in line with these findings.

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Plain film radiography and computed tomography (CT) were evaluated in assessing the consolidation of experimental craniotomy lines covered with titanium miniplates or biodegradable self-reinforced poly-L-lactide (SR-PLLA) plates. Two sagittal (2.3–2.5 mm wide and 22 mm long) symmetrical craniotomy lines were made in the skulls of eight young sheep. One craniotomy line was covered with a biodegradable SR-PLLA plate and the other with a titanium miniplate. Both plates were fixed with four titanium miniscrews. Consolidation of the osteotomies was studied using plain film radiography and CT 6,12, 20, and 52 weeks postoperatively. Microradiography and histology were used for reference. Plain film was not reliable in assessing osseous consolidation because false-positive results were obtained in three osteotomies. Osseous consolidation was more reliably assessed by CT, which showed consolidation on the SR-PLLA side within 20 weeks, whereas none of the titanium-plated lines was consolidated by 52 weeks. Superior consolidation under the resorbable plate was confirmed in histology and microradiography. The radiolucent SR-PLLA plates did not interfere with CT, whereas the titanium plates caused minor CT artifacts.

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

A study was conducted from February 29, 1996, to March 28, 1996, at the University of Brno's Pathology Institute in the Czech Republic to explore the possible application of craniofacial intracranial endoscopic techniques through minimal skin incisions and trephines in fresh cadavers (3 to 12 hours old). Through the trephines the dura was totally dissected from the bone. After this dissection a standard bicoronal incision and a full craniotomy was performed to assess the integrity of the meninges. This minimally invasive dissection of the skull base with the aid of an endoscope is characterized by fewer skin incisions, thereby avoiding the exposure of subcutaneous tissue, muscle, cranial, bone, and meninges. We find that it is possible to accomplish an accurate and extensive intracranial dissection with the aid of an endoscope. The potential of this technique is important for craniofacial surgery as well as for neurosurgery. The objectives of this study were [1] to explore endoscopically the craniofacial anatomy to determine the best approach and the optimal method for dissecting endocranial structures, and [2] to achieve a safer and more accurate dissection of the skull base, evaluating advantages of endoscopic surgery as an alternative method for the treament of craniofacial and neurosurgical pathologies.

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The etiopathogenesis behind the formation of atypical craniofacial facial clefts remains unknown. To test the hypothesis that physical restricting forces such as amniotic bands can lead to the formation of these unusual clefts in the postorganogenesis period, we have modified a previously reported fetal lamb model of amniotic band syndrome to examine the effects of these bands on craniofacial development. Five 70-day gestation fetal lambs (term, 140 days) were exposed via a maternal hysterotomy. In each animal, an attempt was made to create a lateral craniofacial cleft by applying a 2–0 nylon suture as a constriction band to the growing face. The sutures were attached to either the zygomatic arch or the infraorbital rim externally and then looped circumferentially into the oral commissure. Each suture was positioned so as to create either a Tessier type 5 or a Tessier type 7 cleft. Four of five fetal lambs survived to term. Both types of lateral facial clefts were effectively produced using this model. In each group, the presence of an intraoral constriction band led to the formation of macrostomia, with an average 7.4-mm lateral displacement of the oral commissure. In addition to these soft tissue changes, each animal also had partial bony clefting (i.e., a bony groove) induced by the pressure of the restriction band across the growing facial skeleton. In the two lambs with the Tessier type 7 cleft, incomplete bony clefts developed across the zygomatic arch. In three animals with bands placed across the medial infraorbital rim, significant infraorbital and malar bony clefts formed similar to a classic Tessier type 5 facial cleft. No evidence of tissue necrosis, maceration, or ulceration was noted in any animal. These data present, for the first time, evidence that the constriction of craniofacial growth by external forces such as a swallowed amnionic band can lead to the development of lateral facial clefting involving both soft tissue and bony elements. These malformations are likely due to a combination of directly tethering normal tissue migration and an increase in local pressure, which produces cellular ischemia and apoptosis. Furthermore, our data demonstrate that these clefts can occur later in fetal development during a period of facial growth rather than during the period of primary facial morphogenesis.

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Ten New Zealand white 22-week-old rabbits were divided into two groups of five each. The Midas Rex drill with a C-1 drill bit was used to make a full-thickness sagittal osteotomy 2 cm in length. A B-5 bit and footplate attachment were used to make a 2-cm linear osteotomy parallel to the first. Four drill holes 1 mm in diameter were made over the nasal bones on the ipsilateral side. In Group A animals, half of the skull had no irrigation; the other half of the skull was irrigated with room temperature saline. In Group B animals half of the skull was irrigated with iced saline irrigation; the other half of the skull was irrigated with room temperature irrigation fluid, and the osteotomy sites were filled with bone wax. Specimens were harvested at 8 weeks and evaluated grossly and histologically. The results showed that all the drill holes closed in the nasal bones regardless of the type of irrigation used or whether bone wax was used. Iced saline irrigation and room temperature irrigation had similar positive effects on bone formation in contrast to the no-irrigation group, which had inferior bone formation. Bone wax appeared also to have a detrimental effect on bone formation.

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The role of preoperative planning, the geometric changes, and the long-term effects of mandibular distraction have not been previously reported. This study included 10 patients who underwent unilateral (5 patients) or bilateral (5 patients) mandibular distraction. Preoperative, postdistraction, and yearly radiographs (panoramic, posteroanterior, and lateral cephalograms) were reviewed. Postdistraction follow-up ranged from 12 to 70 months. Postdistraction, the mandibles showed evidence of anticipated growth without relapse. This growth rate was variable and dependent on the genetic program of the native bone. Previously reported improvement in temporomandibular joint morphology was maintained in the long term. The resulting shape of the neomandible was most influenced by the vector of placement of the distraction device. When placed vertically, ramal elongation was observed. When placed horizontally, anterior projection of the mandibular body occurred. When placed obliquely, ramal and body elongation occurred with preservation of the gonial angle. After 2 to 5 years of follow-up, continued growth of the neomandible was observed.

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:1997

数据来源: OVID