首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Foda HM 《Plastic and reconstructive surgery》2003,112(5):1408-17; discussion 1418-21
The droopy tip is a common nasal deformity in which the tip is inferiorly rotated. Five hundred consecutive rhinoplasty cases were studied to assess the incidence and causes of the droopy tip deformity and to evaluate the role of three alar cartilage-modifying techniques--lateral crural steal, lateral crural overlay, and tongue in groove--in correcting such a deformity. The external rhinoplasty approach was used in all cases. Only one of the three alar cartilage-modifying techniques was used in each case, and the degree of tip rotation and projection was measured both preoperatively and postoperatively. The incidence of droopy tip was 72 percent, and the use of an alar cartilage-modifying technique was required in 85 percent of these cases to achieve the desired degree of rotation. The main causes of droopy tip included inferiorly oriented alar cartilages (85 percent), overdeveloped scrolls of upper lateral cartilages (73 percent), high anterior septal angle (65 percent), and thick skin of the nasal lobule (56 percent). The lateral crural steal technique increased nasal tip rotation and projection, the lateral crural overlay technique increased tip rotation and decreased tip projection, and the tongue-in-groove technique increased tip rotation without significantly changing the amount of projection. The lateral crural overlay technique resulted in the highest degrees of rotation, followed by the lateral crural steal and finally the tongue-in-groove technique. According to these results, the lateral crural steal technique is best indicated in cases with droopy underprojected nasal tip, the lateral crural overlay technique in cases of droopy overprojected nasal tip, and the tongue-in-groove technique in cases where the droopy nasal tip is associated with an adequate amount of projection.  相似文献   

2.
3.
Rohrich RJ  Adams WP 《Plastic and reconstructive surgery》2001,107(7):1849-63; discussion 1864-8
The boxy nasal tip is characterized by a broad, rectangular appearance of the tip lobule on basal view. This manifests anatomically as one of three types: type I, which features an increased intercrural angle of divergence (greater than 30 degrees) and normal domal arc (4 mm or less) manifesting as the tip-defining points; type II, which features an increased angulation of the domes of the lower lateral segments of cartilage, creating a widened domal arc (greater than 4 mm) and normal angle of divergence (30 degrees or less); and type III, which features a combination of increased angle of divergence (greater than 30 degrees) and widened crural domal arc (4 mm or greater). In this article, the available techniques for correction of the boxy tip are reviewed and an algorithmic approach for the management of this problem is demonstrated using the open approach to rhinoplasty. Using an individualized algorithmic approach with intraoperative nasal tip analysis and three nasal tip suture reshaping techniques, consistent aesthetic results can be obtained in the correction of the boxy nasal tip.  相似文献   

4.
The authors present their surgical technique for the correction of the secondary nasal tip with alar and/or columellar collapse. They employ a cartilage autograft in the form of an anchor or half an anchor which is taken from the auricular concha and is designed according to the requirements of the pathology to be corrected. In their experience, they have observed neither complications with the use of these grafts nor unacceptable scars in the columellar incision.  相似文献   

5.
6.
Rohrich RJ  Raniere J  Ha RY 《Plastic and reconstructive surgery》2002,109(7):2495-505; discussion 2506-8
One of the most common problems affecting both the primary and secondary rhinoplasty patient is deformity of the alar rim. Typically, this deformity is caused by congenital malpositioning, hypoplasia, or surgical weakening of the lateral crura, with the potential for both functional and aesthetic ramifications. Successful correction and prevention of alar rim deformities requires precise preoperative diagnosis and planning. Multiple techniques of varying complexity have been described to treat this common and challenging problem.Over the past 6 years (1994 through 2000), the authors have employed a simple technique in 123 patients for alar retraction that involves the nonanatomic insertion of an autogenous cartilage buttress into an alar-vestibular pocket. Among the 53 patients who underwent primary rhinoplasty in this study, 91 percent experienced correction or prevention of alar notching or collapse. However, correction was achieved for only 73 percent of the patients who underwent secondary rhinoplasty; many of whom had alar retraction secondary to scarring or lining loss. In patients with moderate or significant lining loss or scarring, a lateral crural strut graft is recommended. The alar contour graft provides the foundation in the patient undergoing primary or secondary rhinoplasty for the reestablishment of a normally functioning external nasal valve and an aesthetically pleasing alar contour. This article discusses the anatomic and aesthetic considerations of alar rim deformities and the indications and the surgical technique for the alar contour graft.  相似文献   

7.
Stretching of the abdominal wall and skin following pregnancy or excessive weight gain may be limited to the infraumbilical area. In these patients, abdominal repair may be accomplished with a shorter incision and without the necessity for relocating the umbilicus with its attendant visible scar. Forty patients are presented in whom excellent aesthetic repairs were effected through short curvilinear, low abdominal incisions with removal of a modest amount of excess skin. Fascial plication from pubis to umbilicus or above is facilitated by buried figure-of-eight sutures. Suction-assisted lipectomy may be employed as an adjunct. Recovery is facilitated by the reduced incision line length, reduced undermined area, and absence of tension in the midline skin incision, such as may occur in a standard abdominoplasty in which large amounts of panniculus and skin are removed with a complete repair of the abdominal wall. The limited abdominoplasty may be safely performed with ketamine-diazepam anesthesia in an office surgical center. Major complications are few and generally reflect the unpredictable nature of the elasticity of the abdominal skin.  相似文献   

8.
"Cap" on the tip of Salmonella flagella   总被引:5,自引:0,他引:5  
Flagellar filaments isolated intact from a Salmonella short-flagella mutant are unable to serve as nuclei for flagellin polymerization in vitro, whereas the filaments reconstructed in vitro from the mutant flagellin are able to do so. The inability of intact flagella to nucleate flagellin polymerization appears to be common to wild-type bacteria and thus suggests that the tip of intact flagella are generally inactivated or capped in vivo. Careful observations of the tips of intact flagella and reconstructed flagellar filaments of a wild-type species have revealed marked difference between them: the intact flagella usually have blunt ends, whereas reconstructed filaments have concave, "fish-tail" ends. Moreover, a thin structure is often observed attaching to the very end of the intact flagella. We suspect that this "capping" structure is essential to the elongation mechanism of flagellar filaments.  相似文献   

9.
10.
This article discusses a method for treating the ultraprojecting tip by the resection of columellar skin in open rhinoplasty. Lack of postoperative contraction of columellar skin and soft tissue may result in an "iatrogenic-hanging columella." Columellar skin resection frequently produces its own deformities because of a discrepancy in the width of the columellar base side and the infralobular flap side. The ultraprojecting tip was present in 56 of 660 consecutive rhinoplasty patients (8 percent) over 8 years (1991 to 1998). Of these 56 patients, 48 underwent partial resection of the infralobular skin flap. Of these 48 patients, eight (17 percent) required secondary skin revision of the columellar resection area. The technique was then modified since 1998. Over 2 years, 13 of 129 consecutive rhinoplasty patients (10 percent) were judged to have an ultraprojecting tip. Of these, eight patients were treated with a modification in the technique by resecting skin on the posterior columellar base. No resection areas were revised in the second series. Of the 789 patients in both series, 647 (82 percent) underwent primary rhinoplasties, 126 (16 percent) had secondary rhinoplasties, and 16 (2 percent) had tertiary rhinoplasties. The treatment of excess columella skin adds a subtle aesthetic improvement to the postoperative nasal contour. By resecting skin on the posterior columellar base or the posterior columellar base and, rarely, the anterior flap, an iatrogenic-hanging columella can be avoided.  相似文献   

11.
Until recently, published evidence for the responses of species to climate change had revealed more examples of species expanding than retracting their distributions. However, recent papers on butterflies and frogs now show that population-level and species-level extinctions are occurring. The relative lack of previous information about range retractions and extinctions appears to stem, at least partly, from a failure to survey the distributions of species at sufficiently fine resolution to detect declines, and from a failure to attribute such declines to climate change. The new evidence suggests that climate-driven extinctions and range retractions are already widespread.  相似文献   

12.
13.
14.
15.
16.
转基因作物释放可能导致潜在的生态风险性,其中的一个重要方面是通过花粉的传播将某些转基因(主要是抗除草剂基因)漂入野生近缘种或近缘杂草而引发难以控制的“超级杂草”的产生。本文讨论了防止“超级杂草”产生的若干对策,包括物理隔离、转基因遗传调控、雄性不育性与无融合生殖机制的利用、将转基因定位于同当地杂草不亲和的基因组和叶绿体或线粒体基因组等。  相似文献   

17.
In 1995, the senior author (E.E.F.) published an article in which he described the musculus digastricus septi nasi labialis. In the article presented here, work carried out by anatomists and other researchers who, over the last two centuries, studied nose muscular dynamics is described. The present study is based on Gray's Anatomy, which, in 1858, first described the nasal tip muscles, along with the other nasal muscles. Later works not only used different terminology for these muscles but also ignored some, creating tremendous confusion. The study presented here provides an update of the exact terms, location, insertions, and muscle functions of the muscles of the nose. Each nose muscle is described with regard to the two portions able to produce separate contractions. In this study, the term "dual function" is used and characterizes the nasal mimetic muscles that do not have well-defined fascia. Therefore, there is doubt about the existence of a real nasal superficial muscle aponeurotic system. The musculus myrtiformis seems to have a dual function, inserting in the canine fosse and in the periosteum of the central incisors, forming two portions-one to the septum and the other to the nostril-each of which has specific functions.This study has been based on research in physiognomy, the science of expression. With regard to the basis for nose expressions, common anatomical research is excluded because it provides a different view of the dynamics studied to date. The term trigonum musculare apicis nasi defines the interaction of the musculi compressor narium minor and dilator naris anterior, connecting with the columellar bundle of the musculus digastricus and levering the nasal spine. This muscular trigone creates circular concentric and eccentric movements of the nasal tip.  相似文献   

18.
Efficient routes to access the 2", 3", 4", and 6" registers of the nodulisporic acid (NsA) side chain are disclosed. A mild one-carbon, Ph(2)CdoublebondNCH(2)CtriplebondN mediated homologation of NsA's 3"-aldehyde permitted access to the 4"-register. Curtius reaction of NsA's 3"-acid yielded the corresponding 2"-aldehyde 4 from which the unnatural Delta(2",3")-olefin isomer 2b was obtained. In addition, Arndt-Eistert reactions of the parent NsA permitted a one-carbon homologation to the 6" register. These efforts identified new analogues with significant flea activity and illustrated the biological significance of unsaturation at the 1",2" register.  相似文献   

19.
Elements that excise and integrate, such as prophages, and transfer by conjugation, such as plasmids, have been found in various bacteria. These elements appear to have a diversified set of characteristics including cell-to-cell contact using pili or cell aggregation, transfer of single-stranded or double-stranded DNA, low or high specificity of integration and serine or tyrosine recombinases. This has led to a highly heterogeneous nomenclature, including conjugative transposons, integrative 'plasmids', genomic islands and numerous unclassified elements. However, all these elements excise by site-specific recombination, transfer the resulting circular form by conjugation and integrate by recombination between a specific site of this circular form and a site in the genome of their host. Whereas replication of the circular form probably occurs during conjugation, this replication is not involved in the maintenance of the element. In this review, we show that these elements share very similar characteristics and, therefore, we propose to classify them as integrative and conjugative elements (ICEs). These elements evolve by acquisition or exchanges of modules with various transferable elements including at least ICEs and plasmids. The ICEs are probably widespread among the bacteria.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号