A comparative cephalometric study of the cranial base in craniofacial anomalies: Part I: Tensor analysis

The method of mean tensor analysis was used to study the cranial base in six craniofacial anomalies: Crouzon's disease, Apert's syndrome, Pfeiffer's syndrome, craniofacial microsomia (CFM), Treacher Collins (TC) syndrome, and frontonasal dysplasia (FND). The form was represented by five landmarks: the nasion (N), basion (Ba), sella (S), frontomaxillonasal suture (FMN), and sphenoethmoidal registration point (SE), and the deformities were computed as mean deformations from age- and sex-matched normal mean forms. The cranial base in CFM is normal in shape. The other five syndromes manifest four distinct patterns of shape variation. Only in TC and Pfeiffer's syndrome is the cranial-base angle distinctive. In Apert's and Crouzon's syndromes, point SE is displaced anteriorly upon a cranial base, small in size but otherwise normal in shape. In TC syndrome and FND, point SE is displaced posteriorly toward the sella.     

Sonic hedgehog基因在颅面生长发育中作用的研究

Sonic hedgehog基因与细胞在肢体、体节、神经管发育中的分化建立有关,通过细胞表面特殊受体Ptch和Smo跨膜蛋白被接收和传导,从而激活锌指蛋白Ci/Gli家族.研究Shh信号传导通路的脊椎动物多为小鼠和鸡.Shh与颅面部、眼、脑的正常发育有关,Shh基因敲除小鼠前脑和颅面结构生长严重缺陷,Shh信号的短暂缺失可导致鸡胚颅面发育异常类似距离过近,过度表达导致距离过远,严重者甚至常伴面部重复.     

The effect of chin cup therapy on the growth and development of the cranial base and midface

The purpose of this study was to determine how the growth rates of certain cranial base and midfacial points and dimensions were affected by force application to the mandible by the chin cup. Control and treated samples consisting of Japanese girls with skeletal Class III relationships were analyzed. Each sample consisted of lateral cephalometric radiographs taken annually (control group) or semiannually (treated group) from early childhood through adolescence. The control sample was composed of seven persons and the treated sample of ten persons. The subjects of the treated sample were required to wear a chin cup a minimum of 12 hours per day. The total force delivered was 500 g, 250 g per side, and the direction of force was, on average, through the condyle. No other appliances were used. The results of this study indicate that the chin cup causes a closing of the cranial flexure angle N-S-Ba, inhibits posterior growth of the point basion, and imposes a vertical growth tendency on the points nasion and sella. The chin cup significantly inhibits anterior and posterior vertical maxillary growth and growth of upper anterior facial height. Because development of vertical posterior facial height is inhibited more than anterior facial height, a clockwise rotation of the maxilla occurs. The chin cup also causes flaring and a decrease in eruption rate of the maxillary incisors. It has no effect on the eruption rate of the maxillary molars, but accelerates their rate of mesial movement as compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of growth hormone therapy on mandibular and cranial base development in children treated with total body irradiation

The aim of the present investigation was to study craniomandibular development during growth hormone (GH) therapy in nine girls and one boy, aged between 7.3 and 16 years, who exhibited pronounced growth reduction after total body irradiation (TBI) and bone marrow transplantation (BMT). Age- and sex-matched healthy children with normal dentofacial development constituted the control material. The investigation data were based on measurements made on lateral skull radiographs taken at the start and, on average, 6 months after cessation of GH treatment. The control group comprised similar longitudinal cephalographic records. The results showed that GH therapy in patients who exhibited growth retardation after TBI and BMT had only a minor effect on cranial base dimensions, probably due to the fact that the development of this area is completed at a relatively early age. The effect of GH treatment on mandibular growth was very obvious. The dimensional increase of the mandibular variables in the patients was equivalent to, or in some cases even exceeded, that of the controls. In relation to basion, the mandibular condyles were displaced in a backward/upward direction in the patient group. Displacement in the opposite direction was recorded in the controls. It seems likely that the development seen in the patients is a reflection of a normalization of the condyle-fossa relationship made possible by enhanced condylar growth. This change should be advantageous for the function of the craniomandibular complex.     

Posterior cranial base natural growth and development: A systematic review

Objective:To provide a synthesis of the published studies evaluating the natural growth and development of the human posterior cranial base (S-Ba).Materials and Methods:The search was performed on MEDLINE, Embase, PubMed, and all EBM Reviews electronic databases. In addition, reference lists of the included studies were hand-searched. Articles were included if they analyzed posterior cranial-base growth in humans specifically. Study selection, data extraction, and risk of bias assessment were completed in duplicate. A meta-analysis was not justified.Results:Finally, 23 published studies were selected: 5 cross-sectional and 18 cohort studies. Articles were published between 1955 and 2015, and all were published in English. The sample sizes varied between 20 and 397 individuals and consisted of craniofacial measurements from either living or deceased human skulls. Validity of the measurements was not determined in any of the studies, while six papers reported some form of reliability assessment. All the articles included multiple time points within the same population or data from multiple age groups. Growth of S-Ba was generally agreed to be from spheno-occipital synchondrosis growth. Basion displaced downward and backward and sella turcica moved downward and backward during craniofacial growth. Timing of cessation of S-Ba growth was not conclusive due to limited identified evidence.Conclusions:Current evidence suggests that S-Ba is not totally stable, as its dimensions change throughout craniofacial growth and a minor dimensional change is observed even in late adulthood.     

The use of bone morphogenetic protein gene therapy in craniofacial bone repair

Bone morphogenetic proteins (BMPs) are capable of inducing endochondral bone formation when applied on biologic carriers in numerous mammalian in vivo assay systems. Bone morphogenetic protein gene therapy is also currently being developed to promote osteogenesis for clinical indications such as spinal fusions, craniofacial bone loss, and osteoporosis. In this study, critical-sized mandibular defects were treated with a control adenoviral vector (Ad-beta-gal), a BMP-2 adenoviral vector (Ad-BMP-2), or a BMP-9 adenoviral vector (Ad-BMP-9). Gross tissue examination, radiographic analysis, and histologic analysis demonstrated significant bony healing in the BMP treated groups compared to controls. Osteogenesis was limited to the bony defect, without extension into the surrounding soft tissues. The study suggests that with further development, BMP gene therapy may be potentially useful for repair of bony defects in the craniofacial region.     

不同矢状向错颅底形态特征的研究

目的:比较不同矢状向错的颅底形态,探索其规律性。方法:选取均角型错牙合患者56例,年龄10～15岁,包括安氏Ⅰ类组17例;安氏Ⅱ类组20例,安氏Ⅲ类组19例。对三种牙合型进行颅底指标的测量分析,对测量指标进行单因素方差分析和两两比较。结果:从安氏Ⅱ类到安氏Ⅰ类再到安氏Ⅲ类错牙合患者后颅底长度依次缩短并有统计学差异;颅中基底角依次减小并有统计学差异;颅前基底角和后颅底平面角依次增大并有统计学差异。安氏Ⅱ类错的前颅底长度SN减小,安氏Ⅰ类和安氏Ⅲ类的SN长度没有显著的统计学差异。不同矢状向错牙合的颅底角,蝶鞍角,颅基底角,后颅底平面角和SO-Ar距均无统计学差异。结论:矢状向错牙合颅底结构呈现了一定的规律性,说明颅底的生长部分参与了错的形成;后颅底和蝶筛点对矢状向错的形成意义重大。     

机械应力作用于颅底软骨联合的研究进展

颅底软骨联合在颌面部的生长发育中起了重要作用。除了基因的先天因素外,后天环境因素对于颅底软骨联合生长的影响也不可忽视。机械应力是可以影响颅底软骨生长的最常见环境因素,并且机械应力可应用于治疗部分颅面发育异常相关性疾病,如前牵引常用于治疗面中份发育不足的Ⅲ类错畸形。机械应力作用可引起颅底软骨一系列的改变,并且这些因素之间可能存在相互依赖的关系。本文主要对机械应力作用下,颅底软骨联合中与软骨细胞增殖分化、细胞外基质合成、血管生成等相关改变进行综述。     

大鼠生长发育过程中颅底软骨联合细胞增殖和凋亡的研究

目的研究大鼠生长发育过程中颅底细胞的增殖和凋亡现象,探讨颅底生长发育的变化规律。方法选用出生后4d、8d、16d、32d、48d、64d及128d的SD大鼠,取颅底软骨联合组织,行增殖细胞核抗原(PCNA)免疫组织化学染色标记增殖细胞,末端脱核苷酸转移酶介导的缺口末端标记技术(TUNEL法)标记凋亡细胞,比较观察不同时间段大鼠颅底的细胞增殖和凋亡的表达情况。结果在出生后4d、8d及16d的大鼠可见大量的PCNA阳性细胞存在于软骨联合区,而32d、48d、64d及128d大鼠的软骨联合区仅有少量的PCNA阳性细胞,而在软骨联合区两侧的骨小梁之间的PCNA阳性细胞较多。在出生后4d、8d的大鼠软骨联合的肥大区,交界区发现少数细胞凋亡现象;而在出生后16d、32d、48d及64d的大鼠颅底软骨联合组织的肥大区、交界区和两侧的骨小梁之间发现较多散在的黄色荧光凋亡细胞,并随时间推移凋亡细胞逐渐增多;但在128d的大鼠又几乎未见凋亡细胞。结论在大鼠颅底生长发育过程中,细胞增殖和凋亡存在特定的时空变化规律。     

Regulatory issues during early craniofacial development: a summary

During neurulation, craniofacial structures derived from the first branchial arch are determined to become maxillary, mandibular, and tongue formations. At least four interdependent developmental processes become integrated: (1) allocation of cells into specific lineages (perhaps during gastrulation); (2) regulation of time-dependent differential regulatory and structural gene expressions; (3) positional information resulting in pattern formations; and (4) morphogenesis, histogenesis, and cytodifferentiation. This review highlights progress toward understanding when, where, and how the one-dimensional genetic information encoded within DNA (deoxyribonucleic acid) is sequentially expressed into the embryonic craniofacial complex. Specifically, how might intrinsic autocrine and/or paracrine regulatory factors control the developmental program for early first branchial arch morphogenesis, histogenesis, and cytodifferentiation. Rules learned from normal development should be useful toward advancing the diagnosis, treatment, prognosis, and prevention of congenital craniofacial malformations.     

Duraplasty in cranial base resection.

Complications of cerebrospinal fluid leakage following cranial base surgery are a predominant source of morbidity and mortality. The physical properties of the dura in this region, advanced patient age, previous irradiation, and the extent of tumor resection often limit or complicate the reconstructive options available to cranial base surgeons. We describe a technique that delivers vascularized tissue to the dural wound by transposing a dural flap based on the axial pedicle blood supply from the middle meningeal artery. This "duraplasty" can allow primary closure of defects at the cranial base. The donor site, which is less gravitationally dependent, more accessible, and often not affected by radiation therapy, can be closed using traditional methods. Advantages, disadvantages, and indications for this technique are discussed.