ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Nonsyndromic cleft of the lip and/or palate (CLP or orofacial cleft) derives from an embryopathy with consequent failure of the nasal process and/or palatal shelves fusion. This severe birth defect is one of the most common malformations among live births. Nonsyndromic CLP is composed of two separate entities: cleft lip and palate (CL±P) and cleft palate only (CPO). Both have a genetic background, and environmental factors probably disclose these malformations. In CL±P, several loci have been identified, and, in one case, a specific gene has also been found. In CPO, one gene has been identified, but many more are probably involved. Because of the complexity of the genetics of nonsyndromic CLP as a result of the difference between CL±P and CPO, heterogeneity of each group caused by the number of involved genes, type of inheritance, and interaction with environmental factors, we discuss the more sound results obtained with different approaches: epidemiological studies, animal models, human genetic studies, and in vitro studies.

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Various materials have been proposed for cranial reconstruction. Bone autograft and alloplasts such as polymethylmethacrylate (PMMA) and hydroxyapatite (HA) cement are most commonly used at the present time. Patients submitted for cranioplasty were evaluated. The prognostic factors influencing the results and the outcome were analyzed. Three hundred twelve patients who had 449 procedures performed by a single surgeon to reconstruct a calvarial deformity between 1981 and 2001 were studied. Post-tumor resection deformity was the main reason for cranioplasty (32.4%). Bone graft was the material of choice (69.5%). The main surgical site was the frontal bone (53.2%). Complications were observed in 23.6% of cases and were responsible for the least satisfactory results (P> 0.001), with infection and material exposure being the most critical complications. The eventual outcome was considered good in 91.8% of cases. The use of HA cement was associated with the worst results (P> 0.001). Bone grafts showed a high grade of partial resorption and required further surgery for correction. Multiple surgical procedures were correlated with a high rate of complications and an unsatisfactory outcome. Bone graft and PMMA are still the best materials in calvarial reconstruction. Even though HA cement is an osteoconductive material, it seems to induce what appears to be an immunoguided delayed inflammatory reaction that leads to thinning of the skin and exposure of the material, making secondary repair difficult. Before deciding which reconstructive option to use, a careful evaluation of the patient in terms of diagnosis, number of previous surgeries, and surgical site should be undertaken. If this is adopted, good results and a satisfactory outcome can be achieved on long-term follow-up.

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

The specific aim of this study was to determine the differences between 6 anthropometric (taken from the surface) and cephalometric (taken from x-rays) measurements and 12 proportion indices formed by the measurements obtained from the face of 51 healthy Caucasoid young adult males and females. The z-score analysis revealed negligible differences in frequency of normal values, in surface measurements 97.4% (298 of 306) versus 96.7% (296 of 306) in cephalometric ones. The optimal normal measurements dominated, in males in 76.8% and in females in 80.8%. The mean values of the 6 linear measurements, taken from the surface and the cephalogram of the face were in equal number similar and significantly dissimilar in both sexes (Table 1). Comparison of the mean anthropometric and cephalometric proportion indices did not show significant differences in the two sexes (Table 2). For males 50% of the 12 proportions the indices were similar and 50% were significantly different. For females the frequency of similar proportions was seen in 33.3% and in 66.7% moderately-severely differing, statistically not significant. The z-score analysis identified subnormal measurements on the facial surface in 2.6% (8 of 306) and in cephalometric ones in 3.3% (10 of 306). The subnormal measurements of mild and moderate degree disclosed on the skeleton were not detected on the surface and some of the severely subnormal ones became mild-moderate on the skin surface. The study showed that the vertical anthropometric and cephalometric measurements in the facial profile were in highly significant percentage normal when compared with their normative data established for healthy populations. Generally, the cephalometric normal measurements were smaller than those of the anthropometric ones, some of them significantly. The significant differences between the proportions on the surface and skeleton in healthy subjects advice to be cautious in clinical practice, to judge the morphological changes of the face separately on the surface and on the skeleton of the patient.Table 1.Anthropometric and Cephalometric Measurements in Males and FemalesA, Anthropometric; C, Cephalometric; mm, millimeters; SD, Standard Deviation; NS, not significant; SIG, significant; mild (M) (p = 0.04–0.01); moderate (MOD) (p = 0.009–0.0002); severe (SEV) (p ≤ 0.0001).Table 2.Sex-Related Differences Between Anthropometric and Cephalometric Proportion IndicesM, males; F, females; NS, not significant.

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Stereolithography can be used to produce physical models of the craniofacial skeleton from three-dimensional computed tomography (CT) data. The purpose of this study was to assess its accuracy for modeling osseous defects of the midface. Maxillary resections simulating unilateral maxillectomy (N = 3), bilateral maxillectomy (N = 3), and unilateral orbitomaxillectomy (N = 3) were performed as for sinus tumor resection on nine fresh cadaver skulls. Stereolithographic models (SLMs) were made from the specimen's CT data. The accuracy of SLMs was determined by comparing distances between key landmarks on the skulls and SLMs. Each SLM was grossly accurate with some loss of thin delicate structures. The mean differences in overall dimensions between the SLMs and skull specimens were 1.5 mm (range: 0–5.5 mm) for craniofacial measures, 1.2 mm (range: 0–4.8 mm) for skull base measures, 1.6 (range: 0–5.8 mm) for midface measures, 1.9 mm (range: 0–7.9 mm) for maxilla measures, and 1.5 mm (range: 0–5.7 mm) for orbital measures. The mean differences in defect dimensions were 1.9 mm (range: 0.1–5.7 mm) for unilateral maxillectomy, 0.8 mm (range: 0.2–1.5 mm) for bilateral maxillectomy, and 2.5 mm (range: 0.2–7.0 mm) for orbitomaxillectomy defects. Midface SLMs may be more prone to error than those of other craniofacial regions because of the presence of thin walls and small projections. Thus, one should consider designing midface bone replacements that are larger in critical dimensions than those predicted by preoperative modeling. These findings have important implications for the planning of current surgical methods as well as future applications of tissue-engineered bone replacement.

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Several bioabsorbable internal fixation systems are currently in use in the field of bone surgery. To test the mechanical properties of recently developed amorphous self-reinforced poly-L/DL-lactide [SR-P(L/DL)LA] 70/30 tacks in comparison with commercially available SR-P(L/DL)LA 70/30 (BioSorbFX; Bionx Implants Ltd) miniscrews, SR-P(L/DL)LA miniscrews (length = 6.0 mm, core diameter = 1.5 mm, thread diameter = 2.0 mm) and tacks (length = 5.4 mm, core diameter = 1.5 mm, thread diameter = 2.0 mm) were applied to human cadaveric metatarsal (MT) bones (6 pairs of fourth MT bones and 6 pairs of fifth MT bones from donors who were from 29 to 56 years of age at the time of death). Pullout force was measured using a mechanical testing machine. Forty-eight pullout tests were carried out for each implant type. The Studentttest, Mann-WhitneyUtest, and Spearman coefficient were used for statistical evaluation. The pullout force of tacks was 135.0 ± 26.1 N, and that of the miniscrews was 119.3 ± 26.1 N (P= 0.04, statistically significant difference). Accordingly novel SR-P(L/DL)LA 70/30 tacks have a statistically better pullout strength than the SR-P(L/DL)LA 70/30 miniscrews when tested in cadaver MT bones.

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Heat is one of the fundamental forces that influence the rates of chemical reactions. The hydrolysis of an absorbable polymer is a function of many factors, both material-related and implant-site–related, including temperature. There is variance in temperature among patients as well as among various animals in whichin vivodegradation studies are performed. Thisin vitrostudy investigated the influence of temperature on hydrolysis and found that a variance from 37°C to as little as 2°C can affect the rate of hydrolysis of a PGA/PLLA copolymer about 25–30%, with the rate increasing with increasing temperature. As most animals of biomedical interest have a body temperature on the order of 1–3°C greater than that of humans, it is possible thatin vivoanimal testing may be “worst case”; that is, strength loss may be accelerated in animals relative to that in human patients. Also, variation of body temperature within the human population may contribute to some variance in the rate of hydrolysis from person to person; however, other influences may minimize this effect and make it difficult to observe clinically.

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

The aim of this study was to attempt to establish a correlation between condylar localized fracture, onset of anatomicopathological lesions of the articular structures, and determination of ankylosis so as to define appropriate diagnostic and therapeutic procedures. Clinical, arthroscopic, and histological studies were carried out in two patients with a severe temporomandibular joint disorder after a condylar localized fracture. Treatment included removal of the displaced fragments, condylar surface remodeling, suture of retrodiskal perforations, and diskal repositioning. The histological study of the condylar specimens revealed signs of osteoarthrosis of the articular surface and chondroid metaplasia of the bilaminar zone with early onset of ankylosis. Results of this study confirmed the presence of causal relations between condylar localized fracture and ankylosis with alterations in retrodiskal tissue. These relations are found in 1) tissue damage caused by bony fragments remaining in the articular cavity (underestimated and poorly treated fractures), 2) the lesion that occurs in association with mechanical trauma; and, particularly, c) the disk and retrodiskal impairments caused by catabolic and degenerative osteoarthrotic changes secondary to condylar marrow damage. Thus, timeliness and accuracy of the diagnosis of condylar localized fracture are most important, as are correct diagnosis and treatment before the onset of degenerative anatomicopathological lesions.

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Congenital defects of the calvaria in general and the parietal bones in particular are rare diseases. The latter are of three kinds: 1) cranioschisis, 2) craniodysostosis, and 3) foramina parietalia permagna (FPP). Here, we describe an exceptional anomaly, namely, complete absence of one parietal bone and dysplasia of the other. Agenesis has been reported twice before in the literature. In these cases, the calvarial defect was the only congenital anomaly. In contrast, the patient described in this article exhibited many other congenital deformities, namely, iris coloboma, facial dysmorphism, a large ventricular septal defect of the heart, and a horseshoe kidney. Some of these deformities are associated with neural crest development. Chromosomal analysis was normal in both blood and fibroblasts, and fluorescent in situ hybridization analysis failed to demonstrate a 22q11 deletion as seen in DiGeorge syndrome, a neural crest–related disease complex. Since 2000, the third group of congenital defects of the parietal bones, FPP, has been associated with mutations of the MSX-2 gene. In our case, a genetic analysis of this gene was performed, but no mutations or deletions of MSX-2 were detected.

ISSN:1049-2275    

出版商:OVID    

年代:2003

数据来源: OVID