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BACKGROUND - Anomalies of the meniscus are uncommon. These anomalous formations have been predominately described in the lateral compartment of the knee. Congenital abnormalities of the medial meniscus are rare.
METHODS - Chart and radiographic review of a single patient with a symptomatic congenital abnormality of the medial meniscus.
RESULTS - The patient was a 5-year-old boy with popliteal pterygium who developed painful snapping in the medial knee after anterior hemiepiphyseodesis to improve his knee extension. The patient had achieved full-knee extension from a preoperative 45-degree flexion contracture. The newly developed snapping was attributed to the hemiepiphyseodesis implants. After implant removal, the snapping persisted and was localized at the medial joint line. Through an arthrotomy, a medial meniscus abnormality was identified and excised with resolution of symptoms.
CONCLUSIONS - This report describes a symptomatic congenital abnormality of the medial meniscus in a child with popliteal pterygium. The patient was treated with excision of the anomalous structure with complete resolution of the symptoms. This is the first report of an intra-articular knee anomaly associated with popliteal pterygium syndrome.
OBJECTIVE - Surgical specialty trips to third world countries have been praised and criticized. Our objective was to learn the usefulness of a yearly head and neck surgery trip through initial analysis of 2 years of patient data.
METHODS - We reviewed data from a prospectively maintained repository of surgical patients treated during head and neck surgical trips to Malindi, Kenya, in 2010 and 2011. Basic demographics, distance traveled for care, access to physicians, preoperative diagnosis, surgical procedure(s), and pathology were recorded when available.
RESULTS - In 2 years, 226 surgeries were performed. Patient age ranged between 3 months and 85 years, and gender was evenly split. Half of patients came from outside the town of Malindi, and a third traveled over 100 kilometers for care. The majority reported access to a local physician, yet very few patients were offered prior surgical treatment. The most common operations performed were adenotonsillectomy and hemithyroidectomy. A wide variety of cases were performed, including parotidectomies, maxillectomies, mandibulectomies, cleft lip and palate repair, and free flap reconstructions. Local and national visiting otolaryngologist-head and neck surgeons participated or observed throughout our visits with teaching emphasis based on their skills and specific learning goals.
CONCLUSIONS - Annual surgical specialty trips to rural, resource-limited regions are useful and worthwhile and offer procedures not otherwise available. On such trips, it is important to collect patient, surgical, and pathology data to help visiting surgeons determine the best procedures to teach local physicians and provide needed resources.
OBJECTIVE - Children born with Pierre-Robin Sequence (PRS) have cleft palate, micrognathia, and macroglossia. After the repair of the cleft palate, velopharyngeal insufficiency (VPI) can occur in a subset of patients. We hypothesize that the need for the surgical correction of VPI in PRS children is no different than cleft palate only (CPO) patients.
METHODS - A retrospective study of 21 children with non-syndromic PRS who were matched to 42 non-syndromic, CPO controls for age and sex. We reviewed incidence of VPI, the need for secondary speech surgery, and speech outcomes post-operatively.
RESULTS - Secondary surgery to correct VPI was necessary in 3 of 21 (14.29%) PRS patients (2 Pharyngeal Flaps, 1 Z-plasty), vs. 10 of 42 (23.81%) CPO (9 Pharyngeal Flaps, 1 Z-plasty) controls. Mean age for VPI surgery for PRS vs. controls: 5.33 vs. 6.41 years, respectively. For final speech outcomes, 73.68% of PRS vs. 71.88% of controls showed no evidence of hypernasality, 89.47% of PRS patients vs. 93.75% of controls showed no evidence of hyponasality, and 76.47% of PRS patients vs. 78.13% of controls had normal velopharyngeal competence (p>0.90 for all three measures).
CONCLUSION - Our findings suggest that children born with a Pierre-Robin Sequence do not have a higher rate of post-operative VPI after cleft palate repair and are no more likely to require additional surgical intervention.
Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Genetic variation in the transcription factor interferon regulatory factor 6 (IRF6) causes and contributes risk for oral clefting disorders. We hypothesized that genes regulated by IRF6 are also involved in oral clefting disorders. We used five criteria to identify potential IRF6 target genes; differential gene expression in skin taken from wild-type and Irf6-deficient murine embryos, localization to the Van der Woude syndrome 2 (VWS2) locus at 1p36-1p32, overlapping expression with Irf6, presence of a conserved predicted-binding site in the promoter region, and a mutant murine phenotype that was similar to the Irf6 mutant mouse. Previously, we observed altered expression for 573 genes; 13 were located in the murine region syntenic to the VWS2 locus. Two of these genes, Wdr65 and Stratifin, met 4 of 5 criteria. Wdr65 was a novel gene that encoded a predicted protein of 1,250 amino acids with two WD domains. As potential targets for Irf6 regulation, we hypothesized that disease-causing mutations will be found in WDR65 and Stratifin in individuals with VWS or VWS-like syndromes. We identified a potentially etiologic missense mutation in WDR65 in a person with VWS who does not have an exonic mutation in IRF6. The expression and mutation data were consistent with the hypothesis that WDR65 was a novel gene involved in oral clefting.
The transcription factor TBX1 is a key mediator of developmental abnormalities associated with DiGeorge/Velocardiofacial Syndrome. Studies in mice have demonstrated that decreased dosage of Tbx1 results in defects in pharyngeal arch, cardiovascular, and craniofacial development. The role of Tbx1 in cardiac development has been intensely studied; however, its role in palatal development is poorly understood. By studying the Tbx1-/- mice we found defects during the critical points of palate elongation and elevation. The intrinsic palate defects in the Tbx1-/- mice were determined by measuring changes in palate shelf length, proliferation, apoptosis, expression of relevant growth factors, and in palate fusion assays. Tbx1-/- embryos exhibit cleft palate with failed palate elevation in 100% and abnormal palatal-oral fusions in 50%. In the Tbx1-/- mice the palate shelf length was reduced and tongue height was greater, demonstrating a physical impediment to palate elevation and apposition. In vitro palate fusion assays demonstrate that Tbx1-/- palate shelves are capable of fusion but a roller culture assay showed that the null palatal shelves were unable to elongate. Diminished hyaluronic acid production in the Tbx1-/- palate shelves may explain failed palate shelf elevation. In addition, cell proliferation and apoptosis were perturbed in Tbx1-/- palates. A sharp decrease of Fgf8 expression was detected in the Tbx1-/- palate shelves, suggesting that Fgf8 is dependent on Tbx1 in the palate. Fgf10 is also up-regulated in the Tbx1-/- palate shelves and tongue. These data demonstrate that Tbx1 is a critical transcription factor that guides palatal elongation and elevation and that Fgf8 expression in the palate is Tbx1-dependent.
INTRODUCTION - Cleft lip and palate deformities are one of the most common birth defects. The alveolar cleft requires bony repair to allow proper eruption of dentition. The purpose of this study is to evaluate success in the repair of alveolar clefts and examine whether the addition of allogenic materials improves outcomes.
MATERIALS AND METHODS - One hundred three patients with cleft lip and palate were identified retrospectively after institutional review board approval was obtained. The authors reviewed their medical records, surgical complication rate, need for revision surgery, and whether allogenic materials were used. The data were then compared using analysis of variance.
RESULTS - The average patient age was 16.6 years (range, 7 to 25 years). There were 59% unilateral clefts and 41% bilateral clefts identified. The average age at palate repair was 17.5 months. The average age at alveolar bone grafting (ABG) was 8.9 years (range, 5 to 15 years). Allogenic material was used in 22 primary ABGs and 10 revision ABGs. The revision rate of unilateral ABGs was 18%, which was statistically different from the 32% revision rate of bilateral ABGs. The use of allogenic material during ABG repair did not affect the revision rate.
CONCLUSION - Secondary alveolar bone grafting is necessary for complete rehabilitation of the cleft alveolus. The patients undergoing ABG had an overall 23% revision rate, 18% for unilateral and 32% for bilateral clefts. The use of allogenic materials during ABG did not show a statistical benefit in this study, but future review including more patients may be useful.
Palatogenesis depends on appropriate growth, elevation, and fusion of the palatal shelves and aberration in these processes can lead to palatal clefting. We observed a high incidence of palate clefting in mice deficient in Gli3, known for its role as a repressor in the absence of Shh signaling. In contrast with several current mouse models of cleft palate, Meckel's cartilage extension, cranial neural crest migration, palatal shelf proliferation, apoptosis, and key signaling components mediated by Shh, Bmp, Fgf, and Tgfbeta, appeared unaffected in Gli3-/- mice. Palatal clefting in Gli3-/- mice was consistently associated with tongue abnormalities such as failure to flatten and improper positioning, implicating a critical role of Gli3 and normal tongue morphogenesis for timely palatal shelf elevation and joining. Furthermore, Gli3-/- palatal shelves grown in roller cultures without tongue can fuse suggesting that the abnormal tongue is likely an impediment for palatal shelf joining in Gli3-/- mutants.
Copyright (c) 2008 Wiley-Liss, Inc.
Mammalian palate development is a multistep process, involving initial bilateral downward outgrowth of the palatal shelves from the oral side of the maxillary processes, followed by stage-specific palatal shelf elevation to the horizontal position above the developing tongue and subsequent fusion of the bilateral palatal shelves at the midline to form the intact roof of the oral cavity. While mutations in many genes have been associated with cleft palate pathogenesis, the molecular mechanisms regulating palatal shelf growth, patterning, and elevation are not well understood. Genetic studies of the molecular mechanisms controlling palate development in mutant mouse models are often complicated by early embryonic lethality or gross craniofacial malformation. We report here the development of a mouse strain for tissue-specific analysis of gene function in palate development. We inserted an IresCre bicistronic expression cassette into the 3' untranslated region of the mouse Osr2 gene through gene targeting. We show, upon crossing to the R26R reporter mice, that Cre expression from the Osr2(IresCre) knockin allele activated beta-galactosidase expression specifically throughout the developing palatal mesenchyme from the onset of palatal shelf outgrowth. In addition, the Osr2(IresCre) mice display exclusive Cre-mediated recombination in the glomeruli tissues derived from the metanephric mesenchyme and complete absence of Cre activity in other epithelial and mesenchymal tissues in the developing metanephric kidney. These data indicate that the Osr2(IresCre) knockin mice provide a unique tool for tissue-specific studies of the molecular mechanisms regulating palate and kidney development.
(c) 2007 Wiley-Liss, Inc.
The Crk adaptor protein, which is encoded by two splice variants termed CrkI and CrkII, contains both SH2 and SH3 domains but no catalytic region. It is thought to function in signal transduction processes involved in growth regulation, cell transformation, cell migration, and cell adhesion. Although the function of Crk has been studied in considerable detail in cell culture, its biological role in vivo is still unclear, and no Crk-knockout mouse model has been available. Therefore, we generated a complete null allele of Crk in mice by using the Cre-loxP recombination approach. The majority of Crk-null mice die at late stages of embryonic development, and the remainder succumb shortly after birth. Embryos lacking both CrkI and CrkII exhibited edema, hemorrhage, and cardiac defects. Immunohistochemical examination suggested that defects in vascular smooth muscle caused dilation and rupturing of blood vessels. Problems in nasal development and cleft palate were also observed. These data indicate that Crk is involved in cardiac and craniofacial development and that it plays an essential role in maintaining vascular integrity during embryonic development.
Cleft palate and skull malformations represent some of the most frequent congenital birth defects in the human population. Previous studies have shown that TGFbeta signaling regulates the fate of the medial edge epithelium during palatal fusion and postnatal cranial suture closure during skull development. It is not understood, however, what the functional significance of TGFbeta signaling is in regulating the fate of cranial neural crest (CNC) cells during craniofacial development. We show that mice with Tgfbr2 conditional gene ablation in the CNC have complete cleft secondary palate, calvaria agenesis, and other skull defects with complete phenotype penetrance. Significantly, disruption of the TGFbeta signaling does not adversely affect CNC migration. Cleft palate in Tgfbr2 mutant mice results from a cell proliferation defect within the CNC-derived palatal mesenchyme. The midline epithelium of the mutant palatal shelf remains functionally competent to mediate palatal fusion once the palatal shelves are placed in close contact in vitro. Our data suggests that TGFbeta IIR plays a crucial, cell-autonomous role in regulating the fate of CNC cells during palatogenesis. During skull development, disruption of TGFbeta signaling in the CNC severely impairs cell proliferation in the dura mater, consequently resulting in calvaria agenesis. We provide in vivo evidence that TGFbeta signaling within the CNC-derived dura mater provides essential inductive instruction for both the CNC- and mesoderm-derived calvarial bone development. This study demonstrates that TGFbeta IIR plays an essential role in the development of the CNC and provides a model for the study of abnormal CNC development.