A multiangular approach towards biofabrication of an auricular cartilage implant

Cartilage tissue engineering opens new avenues for reconstruction of auricular deformities. Nevertheless, a number of challenges hinder the development of an auricular cartilage implant, including an appropriate cell source, nutrient limitation in large non-vascularized constructs, and maintenance of the complex auricular shape. This work uses a multiangular approach including biofabrication strategies to address these challenges. Firstly, we investigated the regenerative potential of novel auricular cartilage progenitor cells in 3D printable hydrogels. Furthermore, we proposed a modular construct to decrease the diffusion distance throughout the implant. In addition, the mechanical integrity of the developing construct is warranted by a polymer fiber-reinforced network integrated into a cell-laden hydrogel. Equine auricular cartilage progenitor cells (AuCPC) were encapsulated in 10% gelatin methacrylate (gelMA) hydrogel cylinders and chondrogenically differentiated up to 56 days in vitro. The neocartilage produced by AuCPC displayed GAG/DNA composition and mechanical integrity comparable to auricular chondrocytes (AuCH), and the production of cartilage-like extracellular matrix was confirmed by histology. Polycaprolactone (PCL) scaffolds for custom-designed modular parts of the auricle were fabricated using a Bioscaffolder and combined with gelMA to form hybrid constructs. Light microscopy confirmed homogenous distribution of the hydrogel through the reinforcing network, and the assembled modules displayed a convincing aesthetical appearance under a rubber skin. Bioprinted cell-laden constructs demonstrated homogenous cell distribution and good cell viability after printing up to 7 days of in vitro culture. These results indicate that a multi-faceted approach in creating large tissue constructs is a promising method that warrants further investigation

Hammering K-wires is Superior to Drilling with Irrigation

Cooling during drilling Kirschner wires is not always effective in preventing thermal related damage. In this study, we used a human in vitro model and compared temperature elevation, insertion time, and extraction force between three Kirschner wire insertion methods—drilling with and without irrigation and pneumatic hammering. Forty five Kirschner wires were inserted into 15 fresh human cadaver metacarpals. All three insertion methods were applied in each metacarpal. Drilling without irrigation resulted in a temperature elevation of 67.25 ± 5.4 ºC with significantly lower values for drilling with irrigation (4.15 ± 0.6 ºC) and pneumatic hammering (31.52 ± 3.4 ºC). The insertion time for pneumatic hammering (47.63 ± 8.8 s) was significantly lower compared to drilling without irrigation (263.16 ± 36.5 s) and drilling with irrigation (196.10 ± 28.5 s). Extraction forces after drilling without irrigation, drilling with irrigation, and pneumatic hammering were 39.85 ± 4.1 N, 57.81 ± 6.5 N, and 62.23 ± 6.7 N, respectively. Pneumatic hammering is superior to drilling without irrigation, especially when irrigation is not possible

The relation between clinically diagnosed and parent-reported feeding difficulties in children with and without clefts

A cleft lip and/or palate (CL/P) is one of the most common craniofacial malformations, occurring worldwide in about one in 600-1000 newborn infants. CL/P is known to influence the feeding process negatively, causing feeding difficulties in 25-73% of all children with CL/P. Because there is a risk for serious complications in these children regarding feeding difficulties, there is often a need for intensive medical counseling and treatment. At this moment, adequate diagnosis and measurement remain a challenge and often lead to a delayed referral for professional help. Since parents play a big part in reporting feeding difficulties, it is important to help objectify parents' experiences, as well as the use of a frontline screening instrument for routine check-ups during medical appointments. The aim of this study is to investigate the relationship between parent perspective and standardized observation by medical professionals on feeding difficulties in 60 children with and without clefts at the age of 17 months. We focus on the information from parents and health professionals by comparing the Observation List Spoon Feeding and the Schedule for Oral Motor Assessment with the validated Dutch translation of the Montreal Children's Hospital Feeding Scale. Conclusion: There is a need for timely and adequate diagnosis and referral when it comes to feeding difficulties in children with CL/P. This study underscores the importance of combining both parental observations and measurements of oral motor skills by healthcare professionals to enable this. What is Known: • Early identification of feeding difficulties can prevent adversely affected growth and development. • Clefts increase the probability of feeding difficulties; however, the diagnostic trajectory is unclear. • The Observation List Spoon Feeding (OSF) and Schedule for Oral Motor Assessment (SOMA) are validated to measure oral motor skills. The Montreal Children's Hospital Feeding Scale Dutch version (MCH-FSD) has been validated for the parental perception of infant feeding difficulties. What is New: • Parents of children with CL/P experience relatively few feeding problems in their child on average. • Oral motor skills for spoon feeding are associated with oral motor skills for solid foods in children with CL/P. • The extent of the cleft is associated with experiencing more feeding difficulties in children with CL/P.</p

Effects of absorption coefficients and intermediate-band filling in InAs/GaAs quantum dot solar cells

INTRODUCTION: While options for treatment strategies for infantile hemangiomas (IH) are numerous, evidence-based information about agents, optimal dosage, adverse effects, treatment modality, pretreatment and treatment strategies remain limited. Areas covered: To evaluate side effects and adverse events of medical treatment in children with infantile hemangioma, a comprehensive review of the literature was performed to provide information for daily practice. In total 254 studies were retrieved from medical databases and comprised 10,022 patients divided into 5 different treatment groups. Information about working mechanism, side effects and adverse events of therapies used as a single agent for IH are discussed and evaluated according to information from pharmacotherapeutic databases. Randomized controlled trials have only scarcely been performed for the many therapeutic options reported for IH. Short- and long-term side effects and adverse events, have not been systematically studied. Subsequently information about the medical treatment options and pharmacotheraputic databases for therapy in children with IH are incomplete. Expert opinion: From the many therapeutic options, propranolol is the first-line approach for IH, predominantly based on clinical observation, efficacy and tolerability in the short-term. The unsolved ravels of possible short and long-term adverse events of propranolol used during early developmental stages of children need thorough review

Human adult, pediatric and microtia auricular cartilage harbor fibronectin-adhering progenitor cells with regenerative ear reconstruction potential

Remaining challenges in auricular cartilage tissue engineering include acquiring sufficient amounts of regeneration-competent cells and subsequent production of high-quality neocartilage. Progenitor cells are a resident subpopulation of native cartilage, displaying a high proliferative and cartilage-forming capacity, yet their potential for regenerative medicine is vastly understudied. In this study, human auricular cartilage progenitor cells were newly identified in healthy cartilage and, importantly, in microtia-impaired chondral remnants. Their cartilage repair potential was assessed via in vitro 3D culture upon encapsulation in a gelatin-based hydrogel, and subsequent biochemical, mechanical, and histological analyses. Auricular cartilage progenitor cells demonstrate a potent ability to proliferate without losing their multipotent differentiation ability and to produce cartilage-like matrix in 3D culture. As these cells can be easily obtained through a non-deforming biopsy of the healthy ear or from the otherwise redundant microtia remnant, they can provide an important solution for long-existing challenges in auricular cartilage tissue engineering

Histology of the Pharyngeal Constrictor Muscle in 22q11.2 Deletion Syndrome and Non-Syndromic Children with Velopharyngeal Insufficiency

Plastic surgeons aim to correct velopharyngeal insufficiency manifest by hypernasal speech with a velopharyngoplasty. The functional outcome has been reported to be worse in patients with 22q11.2 deletion syndrome than in patients without the syndrome. A possible explanation is the hypotonia that is often present as part of the syndrome. To confirm a myogenic component of the etiology of velopharyngeal insufficiency in children with 22q11.2 deletion syndrome, specimens of the pharyngeal constrictor muscle were taken from children with and without the syndrome. Histologic properties were compared between the groups. Specimens from the two groups did not differ regarding the presence of increased perimysial or endomysial space, fiber grouping by size or type, internalized nuclei, the percentage type I fibers, or the diameters of type I and type II fibers. In conclusion, a myogenic component of the etiology of velopharyngeal insufficiency in children with 22q11.2 deletion syndrome could not be confirmed

International trends in the treatment of microtia

Background: Microtia is a well-known craniofacial malformation treatable with numerous different treatment strategies and techniques. The purpose of this study was to analyze the current international trends in microtia repair. Methods: All surgeons attending the fourth International Ear Reconstruction Congress in Edinburgh received a questionnaire by e-mail about their current surgical practice in microtia care. Results: Thirty-one questionnaires were received. Most primary reconstructions are performed at ages 8 to 10 years using autologous cartilage from the ipsilateral sixth to eighth ribs. Most surgeons make a multilayer framework, leaving a subcutaneous pedicle. Suction drainage was used in all patients. On average, the second stage was performed more than 6 months later using a mastoid flap. Most surgeons do not reconstruct the middle ear. Conclusions: Microtia reconstruction is performed in many different ways, with numerous treatment and postoperative possibilities. © 2011 by Mutaz B. Habal, MD