Audiological results with Baha in conductive and mixed hearing loss

The level of improvement in the audiological results of Baha(®) users mainly depends on the patient's preoperative hearing thresholds and the type of Baha sound processor used. This investigation shows correlations between the preoperative hearing threshold and postoperative aided thresholds and audiological results in speech understanding in quiet of 84 Baha users with unilateral conductive hearing loss, bilateral conductive hearing loss and bilateral mixed hearing loss. Secondly, speech understanding in noise of 26 Baha users with different Baha sound processors (Compact, Divino, and BP100) is investigated. Linear regression between aided sound field thresholds and bone conduction (BC) thresholds of the better ear shows highest correlation coefficients and the steepest slope. Differences between better BC thresholds and aided sound field thresholds are smallest for mid-frequencies (1 and 2 kHz) and become larger at 0.5 and 4 kHz. For Baha users, the gain in speech recognition in quiet can be expected to lie in the order of magnitude of the gain in their hearing threshold. Compared to its predecessor sound processors Baha(®) Compact and Baha(®) Divino, Baha(®) BP100 improves speech understanding in noise significantly by +0.9 to +4.6 dB signal-to-noise ratio, depending on the setting and the use of directional microphone. For Baha users with unilateral and bilateral conductive hearing loss and bilateral mixed hearing loss, audiological results in aided sound field thresholds can be estimated with the better BC hearing threshold. The benefit in speech understanding in quiet can be expected to be similar to the gain in their sound field hearing threshold. The most recent technology of Baha sound processor improves speech understanding in noise by an order of magnitude that is well perceived by users and which can be very useful in everyday life.

Comparisons of sound processors based on osseointegrated implants in patients with conductive or mixed hearing loss

To compare the patient benefit of the Bone-Anchored Hearing Aid (Baha) Divino and the Baha BP100 sound processors.

Surgery for the bone-anchored hearing aid

This review covers the surgery for the bone-anchored hearing aid (Baha(®)). PREOPERATIVE WORKUP: A review of the indications and preoperative diagnostics shows that best results are generally obtained in patients with conductive or mixed hearing loss rehabilitation when surgery is not applicable or has failed and in patients that suffer from single-sided deafness. An audiogram must confirm that the bone conduction hearing is within the inclusion criteria. A computed tomography scan is performed in cases of malformation to assure sufficient bone thickness at the site of screw implantation.

In vitro induction of lymph node cell proliferation by mouse bone marrow dendritic cells following stimulation with different Echinococcus multilocularis antigens

The immune response of mice experimentally infected with Echinococcus multilocularis metacestodes becomes impaired so as to allow parasite survival and proliferation. Our study tackled the question on how different classes of E. multilocularis antigens (crude vesicular fluid (VF); purified proteinic rec-14-3-3; purified carbohydrate Em2(G11)) are involved in the maturation process of bone-marrow-derived dendritic cells (BMDCs) and subsequent exposure to lymph node (LN) cells. In our experiments, we used BMDCs cultivated from either naïve (control) or alveolar echinococcosis (AE)-infected C57BL/6 mice. We then tested surface markers (CD80, CD86, MHC class II) and cytokine expression levels (interleukin (IL)-10, IL-12p40 and tumour necrosis factor (TNF)-α) of non-stimulated BMDCs versus BMDCs stimulated with different Em-antigens or lipopolysaccharide (LPS). While LPS and rec-14-3-3-antigen were able to induce CD80, CD86 and (to a lower extent) MHC class II surface expression, Em2(G11) and, strikingly, also VF-antigen failed to do so. Similarly, LPS and rec-14-3-3 yielded elevated IL-12, TNF-α and IL-10 expression levels, while Em2(G11) and VF-antigen didn't. When naïve BMDCs were loaded with VF-antigen, they induced a strong non-specific proliferation of uncommitted LN cells. For both, BMDCs or LN cells, isolated from AE-infected mice, proliferation was abrogated. The most striking difference, revealed by comparing naïve with AE-BMDCs, was the complete inability of LPS-stimulated AE-BMDCs to activate lymphocytes from any LN cell group. Overall, the presenting activity of BMDCs from AE-infected mice seemed to trigger unresponsiveness in T cells, especially in the case of VF-antigen stimulation, thus contributing to the suppression of clonal expansion during the chronic phase of AE infection.

Laser Doppler flowmetry for assessment of anterior mandibular teeth in conjunction with bone harvesting in the symphysis: a clinical pilot study

PURPOSE: To evaluate the pulp sensitivity and vitality of mandibular incisors and canines before and after bone harvesting in the symphysis. MATERIALS AND METHODS: In 20 patients requiring bone grafts from the symphysis, pulp sensitivity (carbon dioxide [CO2]) and pulpal blood flow (laser Doppler flowmetry [LDF]) of mandibular incisors and canines were evaluated preoperatively, postoperatively, and 6 months after surgery. Teeth were allocated to 1 of 3 groups according to their initial and final reaction to CO2 (group A = teeth with a positive reaction throughout the study, group B = teeth that exhibited a sensitivity change from positive to negative, and group C = teeth with a negative reaction throughout the study). RESULTS: Preoperative flux measurements (LDF) did not differ between groups A, B, and C. Teeth with sensitivity changes (group B) showed the greatest decrease (a statistically significant decrease) of pulpal blood flow over time, whereas teeth in groups A and C demonstrated an insignificant reduction of flux over time. DISCUSSION AND CONCLUSIONS: LDF was purely used as an experimental tool in the present study. Pulpal blood flow measurements using LDF demonstrated a decrease of flux over time in anterior mandibular teeth following bone harvesting in the symphysis. A significant change of flux, however, was only observed for teeth that also demonstrated a loss of pulp sensitivity during the same study period. Loss of pulp sensitivity appeared to be correlated to a significant decrease of blood flow assessed by LDF.

The effect of matrix bound parathyroid hormone on bone regeneration

INTRODUCTION: Autogenous bone is the most successful bone-grafting material; however, multiple disadvantages continue to drive developments of improved methods for bone regeneration. AIM: The aim of the present study was to test the hypothesis that an arginine-glycine-aspartic acid (RGD) modified polyethylene glycol-based matrix (PEG) containing covalently bound peptides of the parathyroid hormone (PTH(1-34)) enhances bone regeneration to a degree similar to autogenous bone. MATERIAL AND METHODS: Six American foxhounds received a total of 48 cylindrical titanium implants placed in the mandible between the first premolar and the second molar. Five, respectively, 7 months following tooth extraction, implants were placed into the center of surgically created defects. This resulted in a circumferential bone defect simulating an alveolar defect with a circular gap of 1.5 mm. Four treatment modalities were randomly allocated to the four defects per side: (1) PEG-matrix containing 20 microg/ml of PTH(1-34), and 350 microg/ml cys-RGD peptide, (2) PEG alone, (3) autogenous bone and (4) empty defects. Histomorphometric analysis was performed 4 and 12 weeks after implantation. The area fraction of newly formed bone was determined within the former defect and the degree of bone-to-implant contact (BIC) was evaluated both in the defect region and in the apical region of the implant. For statistical analysis ANOVA and subsequent pairwise Student's t-test were applied. RESULTS: Healing was uneventful and all implants were histologically integrated. Histomorphometric analysis after 4 weeks showed an average area fraction of newly formed bone of 41.7+/-1.8% for matrix-PTH, 26.6+/-4.1% for PEG alone, 43.9+/-4.5% for autogenous bone, and 28.9+/-1.5% for empty defects. After 12 weeks, the respective values were 49.4+/-7.0% for matrix-PTH, 39.3+/-5.7% for PEG alone, 50.5+/-3.4% for autogenous bone and 38.7+/-1.9% for empty defects. Statistical analysis after 4 and 12 weeks revealed significantly more newly formed bone in the PTH(1-34) group compared with PEG alone or empty defects, whereas no difference could be detected against autogenous bone. Regarding BIC no significant difference was observed between the four treatment groups neither at 4 nor at 12 weeks. CONCLUSION: It is concluded that an RGD-modified PEG hydrogel containing PTH(1-34) is an effective matrix system to obtain bone regeneration.

Targeted cell replacement with bone marrow cells for airway epithelial regeneration

It has been suggested that some adult bone marrow cells (BMC) can localize to the lung and develop tissue-specific characteristics including those of pulmonary epithelial cells. Here, we show that the combination of mild airway injury (naphthalene-induced) as a conditioning regimen to direct the site of BMC localization and transtracheal delivery of short-term cultured BMC enhances airway localization and adoption of an epithelial-like phenotype. Confocal analysis of airway and alveolar-localized BMC (fluorescently labeled) with epithelial markers shows expression of the pulmonary epithelial proteins, Clara cell secretory protein, and surfactant protein C. To confirm epithelial gene expression by BMC, we generated transgenic mice expressing green fluorescent protein (GFP) driven by the epithelial-specific cytokeratin-18 promoter and injected BMC from these mice transtracheally into wild-type recipients after naphthalene-induced airway injury. BMC retention in the lung was observed for at least 120 days following cell delivery with increasing GFP transgene expression over time. Some BMC cultured in vitro over time also expressed GFP transgene, suggesting epithelial transdifferentiation of the BMC. The results indicate that targeted delivery of BMC can promote airway regeneration.

Maxillary sinus grafting with Bio-Oss or Straumann Bone Ceramic: histomorphometric results from a randomized controlled multicenter clinical trial

INTRODUCTION: This investigation was designed to compare the histomorphometric results from sinus floor augmentation with anorganic bovine bone (ABB) and a new biphasic calcium phosphate, Straumann Bone Ceramic (BCP). MATERIALS AND METHODS: Forty-eight maxillary sinuses were treated in 37 patients. Residual bone width was > or =6 mm and height was > or =3 mm and <8 mm. Lateral sinus augmentation was used, with grafting using either ABB (control group; 23 sinuses) or BCP (test group; 25 sinuses); sites were randomly assigned to the control or test groups. After 180-240 days of healing, implant sites were created and biopsies taken for histological and histomorphometric analyses. The parameters assessed were (1) area fraction of new bone, soft tissue, and graft substitute material in the grafted region; (2) area fraction of bone and soft tissue components in the residual alveolar ridge compartment; and (3) the percentage of surface contact between the graft substitute material and new bone. RESULTS: Measurable biopsies were available from 56% of the test and 81.8% of the control sites. Histology showed close contact between new bone and graft particles for both groups, with no significant differences in the amount of mineralized bone (21.6+/-10.0% for BCP vs. 19.8+/-7.9% for ABB; P=0.53) in the biopsy treatment compartment of test and control site. The bone-to-graft contact was found to be significantly greater for ABB (48.2+/-12.9% vs. 34.0+/-14.0% for BCP). Significantly less remaining percentage of graft substitute material was found in the BCP group (26.6+/-5.2% vs. 37.7+/-8.5% for ABB; P=0.001), with more soft tissue components (46.4+/-7.7% vs. 40.4+/-7.3% for ABB; P=0.07). However, the amount of soft tissue components for both groups was found not to be greater than in the residual alveolar ridge. DISCUSSION: Both ABB and BCP produced similar amounts of newly formed bone, with similar histologic appearance, indicating that both materials are suitable for sinus augmentation for the placement of dental implants. The potential clinical relevance of more soft tissue components and different resorption characteristics of BCP requires further investigation.

Performance of vertebral cancellous bone augmented with compliant PMMA under dynamic loads

Increased fracture risk has been reported for the adjacent vertebral bodies after vertebroplasty. This increase has been partly attributed to the high Young's modulus of commonly used polymethylmethacrylate (PMMA). Therefore, a compliant bone cement of PMMA with a bulk modulus closer to the apparent modulus of cancellous bone has been produced. This compliant bone cement was achieved by introducing pores in the cement. Due to the reduced failure strength of that porous PMMA cement, cancellous bone augmented with such cement could deteriorate under dynamic loading. The aim of the present study was to assess the potential of acute failure, particle generation and mechanical properties of cancellous bone augmented with this compliant cement in comparison to regular cement. For this purpose, vertebral biopsies were augmented with porous- and regular PMMA bone cement, submitted to dynamic tests and compression to failure. Changes in Young's modulus and height due to dynamic loading were determined. Afterwards, yield strength and Young's modulus were determined by compressive tests to failure and compared to the individual composite materials. No failure occurred and no particle generation could be observed during dynamical testing for both groups. Height loss was significantly higher for the porous cement composite (0.53+/-0.21%) in comparison to the biopsies augmented with regular cement (0.16+/-0.1%). Young's modulus of biopsies augmented with porous PMMA was comparable to cancellous bone or porous cement alone (200-700 MPa). The yield strength of those biopsies (21.1+/-4.1 MPa) was around two times higher than for porous cement alone (11.6+/-3.3 MPa).

Interventional management of hypervascular osseous metastasis: role of embolotherapy before orthopedic tumor resection and bone stabilization

OBJECTIVE: The purpose of this study was to evaluate, in relation to intraoperative estimated blood loss (EBL), the effectiveness of preoperative transcatheter arterial embolization of hypervascular osseous metastatic lesions before orthopedic resection and stabilization. MATERIALS AND METHODS: Between June 1987 and November 2007, 22 patients underwent transcatheter arterial embolization of tumors of the long bone, hip, or vertebrae before resection and stabilization. Osseous metastatic lesions from renal cell carcinoma, malignant melanoma, leiomyosarcoma, and prostate cancer were embolized. All patients were treated with a coaxial catheter technique with polyvinyl alcohol (PVA) particles alone or a combination of PVA particles and coils. After embolization, each tumor was angiographically graded according to devascularization (grades 1-3) based on tumor blush after contrast injection into the main tumor-feeding arteries. RESULTS: In patients with complete devascularization (grade 1), mean EBL was calculated to be 1,119 mL, whereas in patients with partial embolization (grades 2 and 3) EBL was 1,788 mL and 2,500 mL. With respect to intraoperative EBL, no significant difference between devascularization grades was found (p > 0.05). Moderate correlation (r = 0.51, p = 0.019) was observed between intraoperative EBL and tumor size before embolization. Only low correlation (r = 0.44, p = 0.046) was found between intraoperative EBL and operating time. Major complications included transient palsy of the sciatic nerve and gluteal abscess in one patient. CONCLUSION: The results of this study support the concept that there is no statistically significant difference among amounts of intraoperative EBL with varying degrees of embolization.

Role for ephrinB2 in postnatal lung alveolar development and elastic matrix integrity

Alveoli are formed in the lung by the insertion of secondary tissue folds, termed septa, which are subsequently remodeled to form the mature alveolar wall. Secondary septation requires interplay between three cell types: endothelial cells forming capillaries, contractile interstitial myofibroblasts, and epithelial cells. Here, we report that postnatal lung alveolization critically requires ephrinB2, a ligand for Eph receptor tyrosine kinases expressed by the microvasculature. Mice homozygous for the hypomorphic knockin allele ephrinB2DeltaV/DeltaV, encoding mutant ephrinB2 with a disrupted C-terminal PDZ interaction motif, show severe postnatal lung defects including an almost complete absence of lung alveoli and abnormal and disorganized elastic matrix. Lung alveolar formation is not sensitive to loss of ephrinB2 cytoplasmic tyrosine phosphorylation sites. Postnatal day 1 mutant lungs show extracellular matrix alterations without differences in proportions of major distal cell populations. We conclude that lung alveolar formation relies on endothelial ephrinB2 function.

Prevalence of bone attrition on knee radiographs and MRI in a community-based cohort

OBJECTIVES: Bone attrition probably constitutes remodeling of the bone, resulting in flattening or depression of the articular surfaces. Defining bone attrition is challenging because it is an accentuation of the normal curvature of the tibial plateaus. We aimed to define bone attrition on magnetic resonance imaging (MRI) of the knee using information from both radiographs and MRIs, and to assess whether bone attrition is common prior to end stage disease osteoarthritis (OA) in the tibio-femoral joint. METHODS: All knees of participants in the community-based sample of the Framingham OA Study were evaluated for bone attrition in radiographs and MRIs. Radiographs were scored based on templates designed to outline the normal contours of the tibio-femoral joint. MRIs were analyzed using the semi-quantitative Whole-Organ Magnetic Resonance Imaging Scoring (WORMS) method. The prevalence of bone attrition was calculated using two different thresholds for MRI scores. RESULTS: Inter-observer agreement for identification of bone attrition was substantial for the radiographs (kappa=0.71, 95% CI 0.67-0.81) and moderate for MRI (kappa=0.56, 95% CI 0.40-0.72). Of 964 knees, 5.7% of the radiographs showed bone attrition. Of these, 91% of MRIs were also read as showing bone attrition. We selected a conservative threshold for bone attrition on MRI scoring (> or = 2 on a 0-3 scale) based on agreement with attrition on the radiograph or when bone attrition on MRI co-occurred with cartilage loss on OA. Using this threshold for bone attrition on MRI, bone attrition was common in knees with OA. For example, in knees with mild OA but no joint space narrowing, 13 of 88 MRIs (14.8%) showed bone attrition. CONCLUSIONS: Using MRI we found that many knees with mild OA without joint narrowing on radiographs had bone attrition, even using conservative definitions. The validity of our definition of bone attrition should be evaluated in further studies. Bone attrition may occur in milder OA and at earlier stages of disease than previously thought.

Complication rates and associated factors in alveolar distraction osteogenesis: a comprehensive review

Despite its growing popularity, alveolar distraction osteogenesis (DO) is a technically challenging operation. The purpose of this review is to estimate the types and frequencies of complications in alveolar DO and to identify factors associated with them. 26 reports of alveolar DO found in the PubMed database that met the criteria for inclusion were studied. 256 patients underwent 270 DO procedures; 109 complications arose in 77 patients (30%) with 77 distractions (29%). In 27/77 patients, more than 1 complication occurred. 20 complications (7%) were a consequence of surgery, 32 (12%) occurred during distraction, 22 (8%) during the consolidation period and 35 (13%) post-distraction. The most common complications were insufficient bone formation following the consolidation period (22 cases, 8%), regression of distraction distance (18 cases, 7%) and problems related to the distractor device (16 cases, 6%). The most severe complications occurred in 4 cases (2%). The type of device used and an augmentation rate of more than 0.5 mm/24 h were significantly related to insufficient bone formation and evidence of complications. This review indicates that complications in alveolar DO are frequent, but rarely cause severe problems or clinical decline. Appropriate treatment selection, surgical technique and adjusted protocol should decrease the number of complications.

Effect of once-yearly zoledronic acid 5 mg on fracture risk and change in femoral neck bone mineral density

Context: In the Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly - Pivotal Fracture Trial (HORIZON-PFT), zoledronic acid (ZOL) 5 mg significantly reduced fracture risk. Objective: To identify factors associated with greater efficacy during ZOL 5 mg treatment. Design, Setting and Patients: Subgroup analysis (preplanned and post hoc) of a multicenter, double-blind, placebo-controlled, 36-month trial in 7765 women with postmenopausal osteoporosis. Intervention: Single infusion of ZOL 5 mg or placebo at baseline, 12 and 24 months. Main Outcome Measures: Primary endpoints: new vertebral fracture and hip fracture. Secondary endpoints: non-vertebral fracture, change in femoral neck bone mineral density (BMD). Baseline risk factor subgroups: age, BMD T-score and vertebral fracture status, total hip BMD, race, weight, geographical region, smoking, height loss, history of falls, physical activity, prior bisphosphonates, creatinine clearance, body mass index (BMI), concomitant osteoporosis medications. Results: Greater ZOL induced effects on vertebral fracture risk with younger age (treatment-by-subgroup interaction P=0.05), normal creatinine clearance (P=0.04), and BMI >/=25 kg/m(2) (P=0.02). There were no significant treatment-factor interactions for hip or non-vertebral fracture or for change in BMD. Conclusions: ZOL appeared more effective in preventing vertebral fracture in younger women, overweight/obese women and women with normal renal function. ZOL had similar effects irrespective of fracture risk factors or femoral neck BMD.

Bone-anchored Hearing Aids: correlation between pure-tone thresholds and outcome in three user groups

OBJECTIVE: To investigate correlations between preoperative hearing thresholds and postoperative aided thresholds and speech understanding of users of Bone-anchored Hearing Aids (BAHA). Such correlations may be useful to estimate the postoperative outcome with BAHA from preoperative data. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS:: Ninety-two adult unilaterally implanted BAHA users in 3 groups: (A) 24 subjects with a unilateral conductive hearing loss, (B) 38 subjects with a bilateral conductive hearing loss, and (C) 30 subjects with single-sided deafness. INTERVENTIONS: Preoperative air-conduction and bone-conduction thresholds and 3-month postoperative aided and unaided sound-field thresholds as well as speech understanding using German 2-digit numbers and monosyllabic words were measured and analyzed. MAIN OUTCOME MEASURES: Correlation between preoperative air-conduction and bone-conduction thresholds of the better and of the poorer ear and postoperative aided thresholds as well as correlations between gain in sound-field threshold and gain in speech understanding. RESULTS: Aided postoperative sound-field thresholds correlate best with BC threshold of the better ear (correlation coefficients, r2 = 0.237 to 0.419, p = 0.0006 to 0.0064, depending on the group of subjects). Improvements in sound-field threshold correspond to improvements in speech understanding. CONCLUSION: When estimating expected postoperative aided sound-field thresholds of BAHA users from preoperative hearing thresholds, the BC threshold of the better ear should be used. For the patient groups considered, speech understanding in quiet can be estimated from the improvement in sound-field thresholds.