A comparative assessment of the dentoskeletal effects of clear aligners vs miniplate-supported posterior intrusion with fixed appliances in adult patients with anterior open bite. A multicenter, retrospective cohort study.

INTRODUCTION: This study aimed to retrospectively evaluate the dentoskeletal effects of clear aligners (Invisalign) vs miniplate-supported posterior intrusion (MSPI) and identify factors associated with posttreatment overbite in adults with anterior open bite. METHODS: Twenty-nine patients treated with Invisalign and 24 with MSPI combined with full-fixed orthodontic appliances were included from 5 orthodontic practices. Pretreatment and posttreatment lateral cephalometric measurements were included as outcomes. Comparisons across groups and identification of final overbite predictors were assessed with regression modeling and machine learning techniques. RESULTS: MSPI induced significantly greater maxillary molar intrusion (1.5 mm; 95% confidence interval [CI], 0.83-2.17; P <0.001), with subsequent reduction of anterior face height (ANS-Me) (-2.77 mm; 95% CI, -3.64 to -1.91; P <0.001), Mp-SN° (-1.95°; 95% CI, -2.77 to -1.12; P <0.001), and ANB° (-1.69°; 95% CI, -2.44 to -0.94; P <0.001) compared with Invisalign. MSPI resulted in a significantly larger increase in SNB° (0.94°; 95% CI, 0.23-1.65; P = 0.01) and point-Pog projection (2.45 mm; 95% CI, 1.12-3.77; P = 0.001). Compared with MSPI, Invisalign had a significantly greater increase in the distance of maxillary (1.05 mm; 95% CI, 0.38-1.72; P = 0.003) and mandibular (0.9 mm; 95% CI, 0.19-1.60; P = 0.01) incisal edges relative to their apical bases, with borderline greater lingual tipping of only the maxillary incisors (2.82°; 95% CI, -0.44 to 6.09; P = 0.09). Appliance type and initial overbite were significant final overbite predictors across all models. However, this difference was only evident in male patients (males [1.65; 95% CI, 0.99-2.32; P <0.001]; female [-0.04; 95% CI, -0.52 to 0.44; P = 0.87]). CONCLUSIONS: Both appliances effectively improve overbite. MSPI applied the correction via molar intrusion and counterclockwise mandibular autorotation, whereas Invisalign via maxillary and mandibular incisor extrusion.

Proteolytic activation of the cytotoxic phenotype during human NK cell development.

NK cells induce apoptosis in target cells via the perforin-mediated delivery of granzyme molecules. Cytotoxic human NK cells can be generated by IL-15-mediated differentiation of CD34(+) cells in vitro and these cultures have been used extensively to analyze the development of the NK cell surface phenotype. We have used NK cell differentiation in vitro together with protease-deficient human NK cells to analyze the acquisition of the cytotoxic phenotype. Granzymes are synthesized as inactive zymogens and are proteolytically activated by the cysteine protease cathepsin C. Cathepsin C is also synthesized as a zymogen and activated by proteolysis. We show that human NK cells generated in vitro undergo granule exocytosis and induce the caspase cascade in target cells. IL-15 and stem cell factor (IL-15 plus SCF) induced the expression of the granzyme B and perforin genes and the activation of cathepsin C and granzyme B zymogens. Perforin activation is also mediated by a cysteine protease and IL-15 plus SCF-mediated differentiation was accompanied by perforin processing. However, cathepsin C-deficient human NK cells revealed that perforin processing could occur in the absence of cathepsin C activity. The combination of IL-15 plus SCF is therefore sufficient to coordinate the development of the NK cell surface phenotype with the expression and proteolytic activation of the cytotoxic machinery, reflecting the central role of IL-15 in NK cell development.

A Novel Capacitive Cochlear Implant Electrode Array Sensing System to Discriminate Failure Patterns.

OBJECTIVES: The research is to propose a sensing system to ensure the electrode array being correctly placed inside the cochlea. Instead of applying extra sensors to the array, the capacitive information from multiple points of the array is gathered and analyzed to determine the state and behavior of the electrode array. METHODS: The sensing system measures electrode bipolar capacitances between multiple pairs of electrodes during the insertion. The principal component analysis (PCA) method is then applied to analysis the recorded data to discriminate insertion patterns. RESULTS: In total, 384 capacitance profiles from electrode pair (1, 2), and electrode pair (15, 16) were analyzed and compared. In an account of both the electrode pairs, the threshold distance was examined to be d = 1.99 at the average comparison type. The experiment results showed the success rate is over 80% to identify buckling during the insertion on a 2D cochlear model. CONCLUSION: This early-stage investigation shows great potential compared with the current practice, which does not provide any feedback to surgeons. The system demonstrates the feasibility of a sensing method for auto-reoccupation electrodes behavior, and it will help surgeons to avoid misplacement of the electrode array inside the cochlea.

A Capacitive Cochlear Implant Electrode Array Sensing System to Discriminate Fold-Over Pattern.

Purpose During insertion of the cochlear implant electrode array, the tip of the array may fold back on itself and can cause serious complications to patients. This article presents a sensing system for cochlear implantation in a cochlear model. The electrode array fold-over behaviors can be detected by analyzing capacitive information from the array tip. Method Depending on the angle of the array tip against the cochlear inner wall when it enters the cochlear model, different insertion patterns of the electrode array could occur, including smooth insertion, buckling, and fold-over. The insertion force simulating the haptic feedback for surgeons and bipolar capacitance signals during the insertion progress were collected and compared. The Pearson correlation coefficient (PCC) was applied to the collected capacitive signals to discriminate the fold-over pattern. Results Forty-six electrode array insertions were conducted and the deviation of the measured insertion force varies between a range of 20% and 30%. The capacitance values from electrode pair (1, 2) were recorded for analyzing. A threshold for the PCC is set to be 0.94 that can successfully discriminate the fold over insertions from the other two types of insertions, with a success rate of 97.83%. Conclusions Capacitive measurement is an effective method for the detection of faulty insertions and the maximization of the outcome of cochlear implantation. The proposed capacitive sensing system can be used in other tissue implants in vessels, spinal cord, or heart.

Association between interleukin-6 polymorphisms and periodontitis in Indian non-smokers.

AIM: Genetic polymorphisms (SNPs) in the interleukin-6 (IL-6) gene have been associated with the presence of periodontitis. The aim of this study was to investigate the association between five SNPs in the IL-6 promoter region and the periodontal status of a rural Indian population. MATERIALS AND METHODS: Two hundred and fifty-one systemically healthy volunteers were clinically assessed by a single calibrated examiner and divided into: healthy individuals and periodontitis patients based on the European Workshop on Periodontitis definitions and on a recently suggested definition, which takes into account age and clinical attachment levels. Their genomic DNA was analysed blindly using real-time polymerase chain reaction to study IL-6 variants. The association between genetic factors and the presence of periodontitis was assessed by logistic regression. RESULTS: The IL-6-174 GG genotype was associated with periodontitis in non-smokers and older subjects (>45 years old). No statistically significant associations were detected between IL-6 haplotypes and periodontal status, after adjusting for confounders. CONCLUSIONS: The IL-6-174 polymorphism showed some evidence of an association with the periodontal status in non-smokers and older subjects in this rural Indian population. This association might be mediated by the effect of IL-6 on inflammatory responses.

Noise Exposure on Human Cochlea During Cochleostomy Formation Using Conventional and a Hand Guided Robotic Drill.

OBJECTIVE: To investigate the disturbance induced in the cochlea during cochleostomy using conventional drill and a hand guided robotic drill. STUDY DESIGN: The study is based on experimental measurements using the Laser Doppler Vibrometer during the drilling processes converted to Sound Pressure Levels (SPL) for comparison. SETTING: The study is based on experimental results of three sets of cochleostomies on human cadaver heads. MAIN OUTCOME MEASURE(S): Robotic drilling, in comparison to the conventional drilling method, creates a consistently lower level of disturbance in cochlea across the hearing frequency range. RESULTS: Robotic drilling, in comparison to the conventional drilling method, creates a consistently lower level of disturbance in cochlea across the hearing frequency range. CONCLUSIONS: It is reasonable to conclude that robotic drilling has a lower possibility of creating acoustic trauma in cochlea that endangers the residual hearing of patients.

Atypical Mesenchymal Stromal Cell Responses to Topographic Modifications of Titanium Biomaterials Indicate Cytoskeletal- and Genetic Plasticity-Based Heterogeneity of Cells.

Titanium (Ti) is widely used as a biomaterial for endosseous implants due to its relatively inert surface oxide layer that enables implanted devices the ability of assembling tissue reparative components that culminate in osseointegration. Topographic modifications in the form of micro- and nanoscaled structures significantly promote osseointegration and enhance the osteogenic differentiation of adult mesenchymal stromal cells (MSCs). While the biological mechanisms central to the differential responses of tissues and cells to Ti surface modifications remain unknown, adhesion and morphological adaptation are amongst the earliest events at the cell-biomaterial interface that are highly influenced by surface topography and profoundly impact the regulation of stem cell fate determination. This study correlated the effects of Ti topographic modifications on adhesion and morphological adaptation of human MSCs with phenotypic change. The results showed that modified Ti topographies precluded the adhesion of a subset of MSCs while incurring distinct morphological constraints on adherent cells. These effects anomalously corresponded with a differential expression of stem cell pluripotency and Wnt signalling-associated markers on both modified surfaces while additionally differing between hydrophobic and hydrophilic surface modifications-though extent of osteogenic differentiation induced by both modified topographies yielded similarly significant higher levels of cellular mineralisation in contrast to polished Ti. These results suggest that in the absence of deposited proteins and soluble factors, both modified topographies incur the selective adhesion of a subpopulation of progenitors with relatively higher cytoskeletal plasticity. While the presence of deposited proteins and soluble factors does not significantly affect adherence of cells, nanotopographic modifications enhance expression of pluripotency markers in proliferative conditions, which are conversely overridden by both modified topographies in osteogenic inductive conditions. Further deciphering the mechanisms underlying cellular selectivity and Ti topographic responsiveness will improve our understanding of stem cell heterogeneity and advance the potential of MSCs in regenerative medicine.

Association between interleukin-6 promoter haplotypes and aggressive periodontitis.

BACKGROUND: Interleukin-6 (IL-6) polymorphisms have been shown to affect IL-6 promoter activity. This study investigated the possible role of IL-6 genetic polymorphisms and haplotypes in the predisposition to aggressive periodontitis (AgP). MATERIAL AND METHODS: A case-control association study on 224 AgP patients and 231 healthy controls was performed in order to detect differences in genotype distributions of five single nucleotide polymorphisms (SNPs) located in the promoter region of the IL-6 gene. RESULTS: The IL-6 -1363 polymorphism was associated with a diagnosis of AgP in subjects of all ethnicities (p=0.006, adjusted logistic regression). The -1480 SNP was associated with LAgP in subjects of all ethnicities (p=0.003). The -1480 and -6106 polymorphisms were associated with Localized AgP in Caucasians (n=24) (p=0.007 and 0.010, respectively). Haplotypes determined by the -1363 and -1480 polymorphisms were also associated with LAgP (p=0.001) in Caucasians. CONCLUSIONS: This study supports the hypothesis of a link between IL-6 genetic factors and AgP and highlights the importance of two IL-6 polymorphisms (-1363 and -1480) in modulating disease phenotype and susceptibility.

Vitamin D receptor polymorphism (-1056 Taq-I) interacts with smoking for the presence and progression of periodontitis.

AIM: The aim of this analysis was to investigate the relationship between a vitamin D receptor (VDR) polymorphism and the diagnosis and progression of periodontitis. MATERIAL AND METHODS: Data were derived from two different studies, including 231 subjects with healthy periodontium, 224 aggressive periodontitis and 79 chronic periodontitis (CP) patients in a case-control investigation. Sixty-one of these CP patients also took part in an observational study with a 1-year follow-up, in which progression of periodontitis was determined at the subject level. All 534 subjects provided a blood sample from which genomic DNA was extracted to study VDR -1056 TaqI polymorphism. RESULTS: The interaction between smoking and VDR polymorphism was associated with the diagnosis of periodontitis in Caucasians [p=0.001, odds ratio (OR)=1.33, 95% confidence intervals (CI)=1.12-1.57] and all subjects (p=0.033, OR=1.60, 95% CI=1.04-2.48). In the longitudinal study, subjects were divided into two clusters at 1 year according to the median number of progressing sites (Delta cumulative attachment loss >2 mm). Logistic regression analysis revealed that the interaction between VDR Taq-I polymorphism and smoking showed limited evidence of association with the "severe progression" cluster (p=0.033, OR=15.24, 95% CI=1.24-187.42). CONCLUSIONS: Vitamin D receptor Taq-I TT polymorphism was moderately associated with both the presence and the progression of periodontitis in smokers, while no association was detected in non-smoking individuals. VDR genetic factors may interact with smoking in the pathogenesis of periodontitis.

Interleukin-6 polymorphisms are associated with pathogenic bacteria in subjects with periodontitis.

BACKGROUND: Growing evidence suggests that individual genetic susceptibility may influence the host's response to infections. Previously, we showed that a common variation in the interleukin (IL)-6 gene was associated with increased odds of detection of common periodontal pathogens from individuals with aggressive periodontitis. The aim of this study was to investigate the association between IL-6 polymorphisms and periodontopathogenic bacteria in a larger, ethnically mixed population of subjects with periodontitis. METHODS: Genomic DNA was extracted from 107 subjects diagnosed with severe forms of periodontitis to study a cluster of polymorphisms in inflammatory genes, including IL-6. The presence of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, and Tannerella forsythia (previously T. forsythensis) in their subgingival biofilm was determined by polymerase chain reaction analysis. Serum IL-6 and C-reactive protein (CRP) concentrations were analyzed by enzyme-linked immunosorbent assay. RESULTS: Multiple logistic regression analysis revealed that the IL-6 -6106 polymorphism was associated with the detection of A. actinomycetemcomitans (P = 0.009; odds ratio [OR] = 3.5; 95% confidence interval [CI]: 1.38 to 9.16) and the concomitant detection of A. actinomycetemcomitans and P. gingivalis (P = 0.015; OR = 3.6; 95% CI: 1.28 to 10.04). The IL-6 -174 polymorphism was associated with increased odds of the concomitant detection of A. actinomycetemcomitans and P. gingivalis (P = 0.042; OR = 2.8; 95% CI: 1.04 to 7.75). Haplotype analysis of all five IL-6 polymorphisms confirmed an association with the detection of A. actinomycetemcomitans (P = 0.046). The IL-6 -6106 polymorphism was also associated with CRP serum levels at multivariate analysis (P = 0.024). CONCLUSIONS: These findings confirm the hypothesis that complex interactions between the microbiota and host genome are at the basis of susceptibility to periodontitis. Periodontal disease may represent a useful model to study the pathways and mechanisms of host-pathogen interactions in inflammatory diseases.

A hand-guided robotic drill for cochleostomy on human cadavers.

BACKGROUND: An arm supported robotic drill has been recently demonstrated for preparing cochleostomies in a pilot research clinical trial. In this paper, a hand-guided robotic drill is presented and tested on human cadaver trials. METHODS: The innovative smart tactile approach can automatically detect drilling mediums and decided when to stop drilling to prevent penetrating the endosteum. The smart sensing scheme has been implemented in a concept of a hand guided robotic drill. RESULTS: Experiments were carried out on two adult cadaveric human bodies for verifying the drilling process and successfully finished cochleostomy on three cochlea. The advantage over a system supported by a mechanical arm includes the flexibility in adjusting the trajectory to initiate cutting without slipping. Using the same concept as a conventional drilling device, the user will also be benefit from the lower setup time and cost, and lower training overhead. CONCLUSION: The hand-guided robotic drill was recently developed for testing on human cadavers. The robotic drill successfully prepared cochleostomies in all three cases.

The effect of metal ions released from different dental implant-abutment couples on osteoblast function and secretion of bone resorbing mediators.

OBJECTIVES: The etiology of the reduced marginal bone loss observed around platform-switched implant-abutment connections is not clear but could be related to the release of variable amounts of corrosion products. The present study evaluated the effect of different concentrations of metal ions released from different implant abutment couples on osteoblastic cell viability, apoptosis and expression of genes related to bone resorption. METHODS: Osteoblastic cells were exposed to five conditions of culture media prepared containing metal ions (titanium, aluminum, vanadium, cobalt, chromium and molybdenum) in different concentrations representing the amounts released from platform-matched and platform-switched implant-abutment couples as a result of an earlier accelerated corrosion experiment. Cell viability was evaluated over 21days using the Alamar Blue assay. Induction of apoptosis was measured after 24h of exposure using flow cytometry. Expression of interleukin-6, interleukin-8, cyclooxygenase-2, caspase-8, osteoprotegerin and receptor activator of nuclear factor kappa-B ligand (RANKL) by osteoblastic cells were analysed after exposure for 1, 3 and 21days using real-time quantitative polymerase chain reaction assay RESULTS: Metal ions in concentrations representing the platform-matched groups led to a reduction in cell viability (P<0.01) up to 7days of exposure. Stimulated cells showed higher rates of early apoptosis (P<0.01) compared to non-treated cells. Metal ions up-regulated the expression of interleukin-6, interleukin-8, cyclooxygenase-2 and RANKL in a dose dependent manner after 1day of exposure (P<0.05). The up-regulation was more pronounced in the groups containing the corrosion products of platform-matched implant-abutment couples. CONCLUSION: Osteoblastic cell viability, apoptosis, and regulation of bone resorbing mediators were significantly altered in the presence of metal ions. The change in cytokine levels expressed was directly proportional to the metal ion concentration. CLINICAL SIGNIFICANCE: The observed biological responses to decreased amounts of metal ions released from platform-switched implant-abutment couples compared to platform-matched couples may partly explain the positive radiographic findings in respect to crestal bone level when utilising the "platform-switching" concept, which highlights the possible role of corrosion products in the mediation of crestal bone loss around dental implants.

Osteogenic stem cell selection for repair and regeneration.

The first osteogenic cells to attach to a titanium (Ti) implant after placement are the multipotent stromal cells (MSCs) that circulate in the bloodstream and are recruited to the site of tissue damage. The reservoirs of these cells are heterogeneous in nature, consisting of a mixture of cells with varying differentiation abilities. In order to utilise these cells and to reduce the chance of unwanted events during regenerative therapies, the selection of a subset of cells that is truly multipotent is required. The behaviour of these cells has been shown to be altered by modifications to Ti implant surfaces, most notably rough, hydrophilic Ti. These changes in behaviour underpin the differences seen in clinical performance of these surfaces. In this study Human bone marrow derived stromal cells (hBMSCs) have been cultured on modified Ti surfaces in order to analyse these changes in cell behaviour. The results demonstrate the different effects of the surfaces and suggest that one surface selectively enriches the population with osteogenic adult 'stem cells' by inducing the cell death of the more differentiated cells. Combined with subsequent expansion in bioreactors before implantation, this may lead to a new source of cells for regenerative therapies.

Mesenchymal stem cell response to topographically modified CoCrMo.

Surface roughness on implant materials has been shown to be highly influential on the behavior of osteogenic cells. Four surface topographies were engineered on cobalt chromium molybdenum (CoCrMo) in order to examine this influence on human mesenchymal stem cells (MSC). These treatments were smooth polished (SMO), acid etched (AE) using HCl 7.4% and H2SO4 76% followed by HNO3 30%, sand blasted, and acid etched using either 50 µm Al2O3 (SLA50) or 250 µm Al2 O3 grit (SLA250). Characterization of the surfaces included energy dispersive X-ray analysis (EDX), contact angle, and surface roughness analysis. Human MSCs were cultured onto the four CoCrMo substrates and markers of cell attachment, retention, proliferation, cytotoxicity, and osteogenic differentiation were studied. Residual aluminum was observed on both SLA surfaces although this appeared to be more widely spread on SLA50, whilst SLA250 was shown to have the roughest topography with an Ra value greater than 1 µm. All substrates were shown to be largely non-cytotoxic although both SLA surfaces were shown to reduce cell attachment, whilst SLA50 also delayed cell proliferation. In contrast, SLA250 stimulated a good rate of proliferation resulting in the largest cell population by day 21. In addition, SLA250 stimulated enhanced cell retention, calcium deposition, and hydroxyapatite formation compared to SMO (p < 0.05). The enhanced response stimulated by SLA250 surface modification may prove advantageous for increasing the bioactivity of implants formed of CoCrMo.

TiO2-coated CoCrMo: improving the osteogenic differentiation and adhesion of mesenchymal stem cells in vitro.

The current gold standard material for orthopedic applications is titanium (Ti), however, other materials such as cobalt-chromium-molybdenum (CoCrMo) are often preferred due to their wear resistance and mechanical strength. This study investigates if the bioactivity of CoCrMo can be enhanced by coating the surface with titanium oxide (TiO2 ) by atmospheric pressure chemical vapor deposition (CVD), thereby replicating the surface oxide layer found on Ti. CoCrMo, TiO2-coated CoCrMo (CCMT) and Ti substrates were used for this study. Cellular f-actin distribution was shown to be noticeably different between cells on CCMT and CoCrMo after 24 h in osteogenic culture, with cells on CCMT exhibiting greater spread with developed protrusions. Osteogenic differentiation was shown to be enhanced on CCMT compared to CoCrMo, with increased calcium ion content per cell (p < 0.05), greater hydroxyapatite nodule formation (p < 0.05) and reduced type I collagen deposition per cell (p < 0.05). The expression of the focal adhesion protein vinculin was shown to be marginally greater on CCMT compared to CoCrMo, whereas AFM results indicated that CCMT required more force to remove a single cell from the substrate surface compared to CoCrMo (p < 0.0001). These data suggest that CVD TiO2 coatings may have the potential to increase the biocompatibility of CoCrMo implantable devices.

The role of cathepsin C in Papillon-Lefèvre syndrome, prepubertal periodontitis, and aggressive periodontitis.

We have previously reported that loss-of-function mutations in the cathepsin C gene (CTSC) result in Papillon-Lefèvre syndrome, an autosomal recessive condition characterized by palmoplantar keratosis and early-onset, severe periodontitis. Others have also reported CTSC mutations in patients with severe prepubertal periodontitis, but without any skin manifestations. The possible role of CTSC variants in more common types of non-mendelian, early-onset, severe periodontitis ("aggressive periodontitis") has not been investigated. In this study, we have investigated the role of CTSC in all three conditions. We demonstrate that PLS is genetically homogeneous and the mutation spectrum that includes three novel mutations (c.386T>A/p.V129E, c.935A>G/p.Q312R, and c.1235A>G/p.Y412C) in 21 PLS families (including eight from our previous study) provides an insight into structure-function relationships of CTSC. Our data also suggest that a complete loss-of-function appears to be necessary for the manifestation of the phenotype, making it unlikely that weak CTSC mutations are a cause of aggressive periodontitis. This was confirmed by analyses of the CTSC activity in 30 subjects with aggressive periodontitis and age-sex matched controls, which demonstrated that there was no significant difference between these two groups (1,728.7 +/- SD 576.8 micro moles/mg/min vs. 1,678.7 +/- SD 527.2 micro moles/mg/min, respectively, p = 0.73). CTSC mutations were detected in only one of two families with prepubertal periodontitis; these did not form a separate functional class with respect to those observed in classical PLS. The affected individuals in the other prepubertal periodontitis family not only lacked CTSC mutations, but in addition did not share the haplotypes at the CTSC locus. These data suggest that prepubertal periodontitis is a genetically heterogeneous disease that, in some families, just represents a partially penetrant PLS.

Robotic technology applied to meet the requirements of tools to support microsurgery and cellular surgery.

Microsurgery and processes involving cell manipulation or cell surgery are clinical practices where the operator works at or beyond the threshold of human dexterity. Current tools available are conventional in their design, and this limits consistency and the level of reliability and achievement. Surgical robotic devices have been explored to improve precision in minimal access surgical procedures to augment control of tool points in tissues, and have enabled feedback of sensory data from which the operator is able to deduce information on the tool at the working site. In this paper, relevant technologies are described that can be harnessed to improve perception of tool point interaction with tissues at the working site and to improve tool control at the small scale required in clinical practice for microsurgery and for cell surgery.

Mechatronic feasibility of minimally invasive, atraumatic cochleostomy.

Robotic assistance in the context of lateral skull base surgery, particularly during cochlear implantation procedures, has been the subject of considerable research over the last decade. The use of robotics during these procedures has the potential to provide significant benefits to the patient by reducing invasiveness when gaining access to the cochlea, as well as reducing intracochlear trauma when performing a cochleostomy. Presented herein is preliminary work on the combination of two robotic systems for reducing invasiveness and trauma in cochlear implantation procedures. A robotic system for minimally invasive inner ear access was combined with a smart drilling tool for robust and safe cochleostomy; evaluation was completed on a single human cadaver specimen. Access to the middle ear was successfully achieved through the facial recess without damage to surrounding anatomical structures; cochleostomy was completed at the planned position with the endosteum remaining intact after drilling as confirmed by microscope evaluation.