Audiologic outcomes and complications of active middle ear implantation in older adults.

BACKGROUND: A few studies have reported the use of middle ear implants (MEIs) in older adults. OBJECTIVES: To evaluate the audiologic outcomes and postoperative complications of MEIs in older adults. METHODS: This retrospective study reviewed audiologic data and medical records from a single referral centre. We identified 34 patients aged ≥65 years who underwent middle ear implantation using the Vibrant SoundbridgeTM device. Preoperative audiometric testing and postoperative aided audiometric testing were performed to evaluate the functional hearing gain at 1 year postoperatively. Patients were divided into 2 groups depending on whether they underwent explantation because of poor hearing benefit. RESULTS: Follow-up duration ranged from <1 to 5.3 years. The functional gain with MEIs significantly improved relative to the preoperative air conduction thresholds at 0.5, 1, 2, and 4 kHz. Eight patients underwent explantation and 7 lost their external audio processor devices. Those who removed their implants because of the poor hearing (group 1) showed significantly worse hearing thresholds at 1 kHz and speech discrimination scores than the others (group 2). CONCLUSIONS AND SIGNIFICANCE: MEIs for auditory rehabilitation can provide improved speech recognition and significant functional gains in older adults. Patients must be given appropriate preoperative explanations regarding the expected outcomes.

Maxillary Sinus Pneumocele Presenting as Aesthetic Deformity: A Case Report With Literature Review.

We report an interesting case of maxillary sinus pneumocele that presented with aesthetic deformity and completely treated with Caldwell-Luc approach and thoroughly review all of the past literature focusing on clinical symptoms and surgical approach. Based on our comprehensive review of maxillary sinus pneumocele, we found 2 important characteristics. First, maxillary sinus pneumocele may be asymptomatic but cause various symptoms owing to the displacement of neighboring structures, such as facial symptoms, eye symptoms, and nasal obstruction. Second, there is no standard operation technique for maxillary sinus pneumocele, but surgical approach should be individualized depending on patient's symptoms and needs. Therefore, more case studies are needed to confirm this.

Novel scaffolds of collagen with bioactive nanofiller for the osteogenic stimulation of bone marrow stromal cells.

The properties of scaffolds and their roles in regulating functions of tissue cells are considered to be of utmost importance in the successful recovery of damaged tissues. Herein, novel scaffolds of collagen and bioactive inorganic nanofiller were produced for bone tissue engineering. In addition, the in vitro responses of bone marrow-derived stromal cells (BMSCs) on these scaffolds were investigated. Glasses with bioactive compositions were prepared in nanofibrous form and homogenized with a collagen to produce hybridized porous scaffolds. The glass fibrous filaments with diameters of a few hundred nanometers were embedded well within the collagen network, characterizing a typical nanocomposite. The scaffolds showed the characteristics of a hydrogel with remarkable water uptake and swelling degree, which were similar to those of the pure collagen. In addition, the scaffolds induced the precipitation of bone-like minerals on the surface under a body-simulating medium, showing the sign of in vitro bone bioactivity. BMSCs adhered and spread well over the scaffold surface and migrated deep into the scaffold network. The osteogenic marker, alkaline phosphatase, was strongly expressed on the hybrid scaffolds, with the level higher than that on pure collagen. Overall, the collagen-inorganic nanofiller scaffolds are considered to find potential utility in bone tissue engineering.

Development of robotic dispensed bioactive scaffolds and human adipose-derived stem cell culturing for bone tissue engineering.

Bioactive and degradable scaffolds made from bioactive glass-polycaprolactone with a mineralized surface and a well-defined three-dimensional (3D) pore configuration were produced using a robotic dispensing technique. Human adipose-derived stem cells (hASCs) were cultured on the 3D scaffolds, and the osteogenic development of cells within the scaffolds was addressed under a dynamic flow perfusion system for bone tissue engineering. The bioactive glass component introduced within the composite assisted in the surface mineralization of the 3D scaffolds. The hASCs initially adhered well and grew actively over the mineralized surface, and migrated deep into the channels of the 3D scaffold. In particular, dynamic perfusion culturing helped the cells to proliferate better on the 3D structure compared to that under static culturing condition. After 4 weeks of culturing by dynamic perfusion, the cells not only covered the scaffold surface completely but also filled the pore channels bridging the stems. The osteogenic differentiation of the hASCs with the input of osteogenic factors was stimulated significantly by the dynamic perfusion flow, as determined by alkaline phosphate expression. Overall, the culturing of hASCs upon the currently developed 3D scaffold in conjunction with the dynamic perfusion method may be useful for tissue engineering of bone.

Evacuated calcium phosphate spherical microcarriers for bone regeneration.

Microparticulates are an effective three-dimensional (3D) matrix for the culture of stem cells to be used in tissue engineering of bone. Herein, bioactive calcium phosphate microparticles with an evacuated morphology were prepared, and their potential to support stem cells for bone tissue engineering was addressed. Spherical particles with sizes of hundreds of micrometers were produced using the emulsification method, during which the internal portion was evacuated with the aid of solvent evaporation. The evacuated portion of the microspheres, which is considered to enhance cell population and be replaced with new bone, was found to comprise approximately 65-70% of the total volume. Stem cells derived from human adipose and rat bone marrow were isolated and cultured on the evacuated microspheres. When compared to a two-dimensional culture dish, the 3D spherical substrate provided cells with more space to adhere and populate, which became more evident as the cell seeding quantity increased. Moreover, better cell proliferation was observed on the evacuated microspheres than on the conventional filled microspheres, suggesting that evacuation of the internal part of the microspheres was useful for generating a large cell population. The differentiation of cells cultured on the 3D evacuated microspheres into osteoblasts with appropriate osteogenic cues was also more effective when compared to cells cultured on a two-dimensional dish. When implanted within a rabbit calvarium, the evacuated microspheres induced rapid bone formation at 6 weeks with a typical lamella pattern. Based on the results, the evacuated calcium phosphate microspheres are considered an effective 3D matrix for direct filling of bone defects as well as for bone tissue engineering using stem cells.

Robotic dispensing of composite scaffolds and in vitro responses of bone marrow stromal cells.

The development of bioactive scaffolds with a designed pore configuration is of particular importance in bone tissue engineering. In this study, bone scaffolds with a controlled pore structure and a bioactive composition were produced using a robotic dispensing technique. A poly(epsilon-caprolactone) (PCL) and hydroxyapatite (HA) composite solution (PCL/HA = 1) was constructed into a 3-dimensional (3D) porous scaffold by fiber deposition and layer-by-layer assembly using a computer-aided robocasting machine. The in vitro tissue cell compatibility was examined using rat bone marrow stromal cells (rBMSCs). The adhesion and growth of cells onto the robotic dispensed scaffolds were observed to be limited by applying the conventional cell seeding technique. However, the initially adhered cells were viable on the scaffold surface. The alkaline phosphatase activity of the cells was significantly higher on the HA-PCL than on the PCL and control culture dish, suggesting that the robotic dispensed HA-PCL scaffold should stimulate the osteogenic differentiation of rBMSCs. Moreover, the expression of a series of bone-associated genes, including alkaline phosphatase and collagen type I, was highly up-regulated on the HA-PCL scaffold as compared to that on the pure PCL scaffold. Overall, the robotic dispensed HA-PCL is considered to find potential use as a bioactive 3D scaffold for bone tissue engineering.

Nanofibrous membrane of collagen-polycaprolactone for cell growth and tissue regeneration.

Nanofibrous substrates of synthetic polymers including polycaprolactone (PCL) have shown considerable potential in tissue regeneration. This paper reports the use of PCL/collagen nanofibers to improve the in vitro osteoblastic responses for the applications in bone regeneration area. Collagen and PCL were dissolved in a co-solvent, and the resulting solution was electrospun into a nanofibrous web. Nonwoven fibrous matrices were successfully produced at various compositional ratios (PCL/collagen = 1/3, 1 and 3 by weight). Although the PCL nanofiber was hydrophobic, the presence of collagen significantly improved the water affinity, such as the water contact angle and water uptake capacity. Tensile mechanical tests showed that the collagen-PCL nanofiber had a significantly higher extension rate (approximately 2.8-fold) than the PCL while maintaining the maximum tensile load in a similar range. The osteoblastic cells cultured on the collagen-PCL nanofibrous substrate showed better initial adhesion and a higher level of growth than those cultured on the PCL nanofiber. Furthermore, real-time RT-PCR revealed the expression of a series of bone-associated genes, including osteopontin, collagen type I and alkaline phosphatase. The expression of these genes was significantly higher on the collagen-PCL nanofiber than on the PCL nanofiber. When subcutaneously implanted in mouse the collagen-PCL membrane facilitated tissue cells to well penetrate into the nanofibrous structure at day 7, whilst no such cell penetration was noticed in the pure PCL nanofiber. Overall, the presence of collagen within the PCL nanofiber improves the water affinity, tensile extension rate, and the tissue cell responses, such as initial adhesion, growth, penetration and the expression of bone-associated genes. Therefore, the collagen-PCL nanofibrous membrane may have potential applications in the cell growth and bone tissue regeneration.

Tissue engineering polymeric microcarriers with macroporous morphology and bone-bioactive surface.

PCL microspheres featuring a macroporous morphology and a bone-bioactive surface have been prepared. 'Camphene' was introduced to generate pores within the microsphere network. The pore size was variable from a few to tens to hundreds of microm depending on the Camphene/PCL ratio. Macropores (with sizes >50 microm) could be obtained with a Camphene/PCL ratio exceeding 6. The microsphere surface was further tailored with apatite mineral phase through solution-mediated precipitation, to endow the interface with bone bioactivity. Rat bone marrow stromal cells attached and spread actively on microspheres and populated well within their macropores. The developed microspheres may be potentially applicable as a cell delivery scaffold for bone tissue engineering.

Preparation of hydroxyapatite spheres with an internal cavity as a scaffold for hard tissue regeneration.

Microparticulates are currently regarded as a useful matrix for the delivery of bioactive molecules and tissue cells. Herein, hydroxyapatite (HA) spherical microparticulates with an internal cavity were produced using an oil-in-water emulsion technique. The HA slurry in the organic solvent was formulated into spherical particles in a water bath containing a surfactant. Rapid evaporation of the solvent helped create a cavity within the microparticulates. The microparticulates were heat-treated at 1,200 degrees C to produce bioactive HA particles with a mean size of approximately 363 microm. Osteoblastic cells were observed to spread and grow favorably over the surface as well as within the cavity of the microparticulates. The currently developed HA microparticulates with an internal cavity are considered to be useful as a scaffolding matrix for bone tissue engineering and direct filling skeletal defects.