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Cochlear implant (CI) surgery is one of the most utilized treatments for severe hearing loss. However, the effects of a successful scala tympani insertion on the mechanics of hearing are not yet fully understood. This paper presents a finite element (FE) model of the chinchilla inner ear for studying the interrelationship between the mechanical function and the insertion angle of a CI electrode. This FE model includes a three-chambered cochlea and full vestibular system, accomplished using µ-MRI and µ-CT scanning technologies. This models first application found minimal loss of residual hearing due to insertion angle after CI surgery, and this indicates that it is a reliable and helpful tool for future applications in CI design, surgical planning, and stimuli setup.

IntroductionWell-organized nasal-associated lymphoid tissue (NALT) has been identified in the pharyngeal and tubal tonsils of both adults and children, and diffuse NALT has been identified in the superior, middle and inferior turbinate regions of children. However, it is not clear how to target these NALT sites with aerosolized vaccines. We explored whether head position and/or angle and distance of device insertion could be used to target fluorescein aerosol to NALT sites in three-dimensional printed models of the intranasal airways of an 18- and a 5-year-old (yo).MethodsThree head positions (upright [Up], tilted back 45° [45] and supine [Su]), two angles of insertion (30° and 45°) and two distances of insertion (6 mm and 9 mm) were tested. Fluorescein aerosol was generated by an Aptar Pharma BiVax 200 µL intranasal atomizer. Percent fluorescein deposition was quantified in the anterior nose, the upper horizontal third of the model (superior turbinate region), middle third (middle turbinate), lower third (inferior turbinate and nasopharynx combined) and exit filter.ResultsMean percent deposition in both models was 45 > Su (p = 0.03).DiscussionThese results suggest that, in individuals with similar nasal airway dimensions as our models: 1) supine and upright head positions might be used to target delivery of aerosolized vaccines generated by the BiVax intranasal atomizer to NALT sites in the middle turbinate and the inferior turbinate and nasopharynx combined, respectively; 2) delivery to the middle turbinate may be higher in children ≤5-yo; and 3) deposition in the anterior nose may be higher in adults, for all head positions. In vivo tests are needed to confirm these findings.

Introduction. Railway transport has ultrasonic control as one of the main methods of detection of defects of the type of continuity violation (cracks, pores and others) both in the base metal and in weld seams of various items. Ultrasonic control tools primarily include a flaw detector with piezoelectric transducers. Piezoelectric transducers are usually supplied with the flaw detector depending on the general or specialized configuration. Flaw detector manufacturers often offer the customer their own piezoelectric transducer kits for certain device configurations with installed software referring to incompatibility of other manufacturers piezoelectric transducers with the electronic unit. The article is intended to carry out a comparative analysis of ultrasonic control sensitivity using straight and angle transducers of different manufacturers, and to compare the results with the control sensitivity using piezoelectric transducers traditionally used on the railways.Materials and methods. The paper gives the results of testing the sample using Flaw Detector UD2-102 Peleng produced by Altek LLC. Industrial oil I-20 was used as a contact fluid. The authors compared the following piezoelectric transducers: straight (made by Altek LLC and NPO INAKON (Russia)) and angle (Altek LLC (Russia), Iskatel-2 LLC (Russia) and SIUI (China)).Results. The paper reports the results of an experiment detecting artificial reflectors in the form of through cylindrical side holes in a sample of 20GL steel by straight and angle piezoelectric transducers of different manufacturers using Flaw Detector UD2-102 Peleng.Discussion and conclusion. Connection of other manufacturers transducers to Flaw Detector UD2-102 Peleng of Altek LLC confirmed that they are compatible with the electronic unit. Thus, given the choice of a wide selection of piezoelectric converters from various manufacturers, the requirement of coordination with the electronic unit of Flaw Detector UD2-102 may be neglected. At the same time, it is important that the manufacturer stipulates the joint use of its product with other types of flaw detectors.

Background and Objectives: The intrusion of anterior teeth is a routine procedure in orthodontics, which has been performed efficiently with the help of mini‐screws in the anterior region, especially the upper maxilla. This study aimed to investigate the effect of insertion angle and sociodemographic features on the success rate of mini‐screws at the anterior maxillary region. Materials and Methods: Twenty‐nine patients (18 Females and 11 Males) aged 18‐40 years old were involved in the current study. A split‐mouth design was carried out in which recruited patients needed bilateral anterior screws at the labial bone in the region of the incisor for the intrusion of upper anterior incisor teeth as part of their orthodontic treatment with a fixed appliance (upper right side received 90‐degree insertion angle mini‐screw and 45° for left side) using a surgical guide fabricated from patients CBCT and intraoral scans. The mini‐screws were inserted at the attached gingiva bilaterally to achieve intrusion of upper anterior teeth with a power chain ligated from the main archwire to the anterior min‐implants. The patient was recalled monthly for orthodontic appliance activation and screw assessment for 6 months. The intrusion force was 15 g on each side. Results: The results of the study showed that screw stability was higher in the male group than the female group at the 6th monthly follow‐up visit with a statistically significant difference between both genders (P =.044). Concerning insertion angle, results showed a statistically significant difference between 45° and 90° as an insertion angle with a P‐value <.01 in most of the follow‐up months. Conclusion: This study found that male patients with mini‐screws inserted at 90° showed greater screw stability over time. [ABSTRACT FROM AUTHOR]

AbstractA predictive finite element model was developed to investigate the best configuration of a fixation pins system consisting of two K-wires inserted in a synthetic model (Sawbones®) at different angles and secured to a connecting rod. Two key parameters were considered to determine the best configuration delivering the higher pull-out strength and lower pull-out length: the diameter and insertion angle. Results show that as the diameter and insertion angle increased, the pull-out force increased, while the pull-out length decreased. Results are successfully compared with available experimental data in literature. This model can be used as an alternative to experimental study. [ABSTRACT FROM AUTHOR]

Purpose: In cochlear implantation with flexible lateral wall electrode arrays, a cochlear coverage (CC) range between 70% and 80% is considered ideal for optimal speech perception. To achieve this CC, the cochlear implant (CI) electrode array has to be chosen according to the individual cochlear duct length (CDL). Here, we mathematically analyzed the suitability of different flexible lateral wall electrode array lengths covering between 70% and 80% of the CDL. Methods: In a retrospective cross-sectional study preoperative high-resolution computed tomography (HRCT) from patients undergoing cochlear implantation was investigated. The CDL was estimated using an otosurgical planning software and the CI electrode array lengths covering 70–80% of the CDL was calculated using (i) linear and (ii) non-linear models. Results: The analysis of 120 HRCT data sets showed significantly different model-dependent CDL. Significant differences between the CC of 70% assessed from linear and non-linear models (mean difference: 2.5 mm, p < 0.001) and the CC of 80% assessed from linear and non-linear models (mean difference: 1.5 mm, p < 0.001) were found. In up to 25% of the patients none of the existing flexible lateral wall electrode arrays fit into this range. In 59 cases (49,2%) the models did not agree on the suitable electrode arrays. Conclusions: The CC varies depending on the underlying CDL approximation, which critically influences electrode array choice. Based on the literature, we hypothesize that the non-linear method systematically overestimates the CC and may lead to rather too short electrode array choices. Future studies need to assess the accuracy of the individual mathematical models. [ABSTRACT FROM AUTHOR]

Background and Objective: The stability of the mini-screw is an important factor for the success of orthodontic treatment using an absolute anchorage system. This study aims to evaluate the ideal insertion angle of a mini-implant in relation to force direction and to evaluate the maximum amount of force application at a specific angular configuration. Method: In this experimental study 72 mini-screws were used, 36 of them were used for each shear and tensile force tests, eighteen samples were taken for the bone density D2 (nine for 60ₒ angle, and nine for 90ₒ angle), and 18 others were taken for the bone density D3 (nine for 60ₒ angle, and nine for 90ₒ angle). Guiding stents were fabricated for proper insertion angle, torque and speed were controlled by contra -angled handpiece. Shear and tensile force tests are done with the aid of a Universal Testing Machine. Results: Mini-implants inserted at 90̊ angle over D2 density bone had higher stability when performing the tensile force test, while in the shear force test mini-implants placed at 60̊ angle were more stable when inserted on bony blocks with D3 density, however it was noted that the results were statistically not significant when compared with 60̊ insertion on blocks with D2 density. Conclusion: To maintain a stable mini-implant during the orthodontic process, the ideal insertion angle is 90̊ when the force direction is vertical, tensile force, and its more appropriate to place the mini-implant at 60̊ angle when the direction of force is in a horizontal direction, shear force.

Objective To assess the bone thicknesses of the infrazygomatic crest in the adult patients with different vertical skeletal patterns of skeletal classⅠmalocclusion based on cone-beam computed tomography (CBCT), and to provide the basis for the choice of clinical treatment methods for the orthodontists. Methods A total of 90 adult patients with skeletal class I malocclusion were selected and divided into low angle group, average angle group, and high angle group, and there were 30 patients in each group. The buccal bone thickness of the patients at different vertical levels and proximal, distal and mesial levels were detected on the CBCT images and the effective bone volume was measured at buccal alveolar bone thickness ≥ 3 mm with the 50°, 60°and 70° implantation angles. Results In different vertical sections, except for the proximal mesiobuccal root level of the maxillary first molar (U6mb), the buccal alveolar bone thickness was increased gradually from the top of the alveolar ridge to the root side (P<0.05) . At different proximal, distal and mesial levels, the buccal bone thickness of the patients was gradually increased from the proximal to the distal mesial direction in all levels except U6mb (P<0.05) . The maximum buccal bone thickness of the patients was 11 mm from the top of the alveolar ridge at the proximal mesiobuccal root of the maxillary second molar (U7mb) ； the minimum buccal bone thickness was 7 mm from the top of the alveolar ridge at U6mb.There was significant difference in the buccal bone thickness of the patients with different vertical bone facial types (P<0.05), the buccal bone thickness of the patients in low angle group was higher than those in average angle group and high angle group (P<0.05), and the buccal bone thickness of the patients in average angle group was higher than that in high angle group (P<0.05) .Among the patients in low angle group, there were significant differences in bone thicknesses between the distal mesiobuccal root of the maxillary first molar and the proximal mesiobuccal root of the maxillary second molar (U6db-U7mb) at from the top of the alveolar crest was 7 mm, at U7mb when the distance from the top of the alveolar crest was 7 mm and 9 mm, at U6mb-U6db when the distance from the top of the alveolar crest was 11 mm at three angles (P<0.05) .The bone thickness was ≥6 mm at U6db-U7mb, when the distance from the top of the alveolar crest was 7 mm at three angles, and when the distance from the top of the alveolar crest was 9 mm at 70° at U7mb.Among the patients in average angle group, there were significant differences in the bone thicknesses between U6db-U7mb at 9 mm from the top of the alveolar crest, U7mb at 9 mm and 11 mm from the top of the alveolar crest at three implantation angles, and the bone thickness ≥6 mm at U7mb when the distance from the top of the alveolar crest at three angles was 7 mm and at U7mb when the distance from the top of the alveolar crest was 9 mm at 70° (P<0.05). Among the patients in high angle group, there were significant differences in bone thickness between U6db-U7mb 11 mm from the top of the alveolar ridge and U7mb 11 mm from the top of the alveolar ridge at three implantation angles (P<0.05) . The thicknesses of bone implantation at different angles could be ranked as follows, 70°>50°>60° in all dimensions. Conclusion There are differences in the buccal bone thickness in the zygomatic crest area among the adult patients with different vertical facial bone patterns. The patients in low angle group have more options for the implantation sites, while the patients in high angle group are more prone to maxillary sinus perforation.Therefore, when placing dental implants and designing orthodontic treatment plans in this area, the vertical facial bone pattern should be taken into consideration. [ABSTRACT FROM AUTHOR]

ObjectiveThe inverted triangle configuration of the three cannulated screws is the classic fixation method most commonly performed for undisplaced femoral neck fractures in young and geriatric patients. However, the posterosuperior screw has a high incidence of cortical breach, known as an in-out-in (IOI) screw. In this study, we present a novel posterosuperior screw placement strategy to prevent the screw from becoming IOI.MethodsUsing computed tomography data and image-processing software, 91 undisplaced femoral neck fractures were reconstructed. The anteroposterior (AP), lateral, and axial radiographs were simulated. To simulate the intraoperative screw placement process, participants used three screw insertion angles (0°, 10°, and 20°) to place the screw on the AP and lateral views of the radiograph according to the three established strategies. On the AP radiograph, a screw was placed abutting (strategy 1), 3.25 mm away from (strategy 2), or 6.5 mm away from (strategy 3) the superior border of the femoral neck. On the lateral radiograph, all the screws were placed abutting the posterior border of the femoral neck. Axial radiographs were used to evaluate the screw position.ResultsIn strategy 1, all the placed screws were IOI regardless of the screw insertion angle. In strategy 2, 48.3% (44/91) of IOI screws occurred at a 0° screw insertion angle, 41.7% (38/91) of IOI screws occurred at a 10° screw insertion angle, and 42.9% (39/91) of IOI screws occurred at a 20° screw insertion angle situation. In strategy 3, no IOI screw occurred, and the screw insertion angles did not affect the safety and accuracy of screw placement.ConclusionsScrews placed according to strategy 3 are safe. The reliability of this screw placement strategy is unaffected by a screw insertion angle of less than 20 degrees.

Background. The present study aimed to assess the stress and strain distribution on mini-screws and the surrounding bone in cases of different cortical bone thicknesses (CBTs), mini-screw insertion angles, and force directions using finite element analysis (FEA). Methods. Inventor professional version 8 software was used to construct 24 three-dimensional assemblies of mini-screws inserted with different insertion angles (30º, 60º, and 90º) in alveolar bone blocks with different CBTs (0.5, 1, 1.5, and 2 mm). The models simulated mini-screws inserted in bones with different CBTs and different insertion angles. A 2-N load was applied in two directions to mini-screw heads. The resultant stresses of the applied load were collected from the output of the ANSYS program. Results. The results indicated that force direction affected bone strains as the horizontal force generated more strains on cortical bone than the oblique one. Force applied to 60º inserted mini-screws generated much more strains on cortical bone than 90º and 30º inserted mini-screws. In a 60º inserted mini-screw, the horizontal force generated about 45% more strains on cortical bone than the oblique one. The exerted microstrain on bone decreased as CBT increased. Conclusion. It can be concluded that inserting mini-screws at 60º to the bone surface should be avoided as it generates much more strains on cortical bone than 90º and 30º, especially when a force parallel to the bone surface is applied.

Abstract Background To investigate the efficacy of a nickel-titanium (NiTi) file with an automated computerized numerical control (CNC) system for root canal shaping. Methods The movement of the automated device and the insertion angle were investigated. In Experiment 1, simulated resin root canals were randomly divided into four groups (n = 20): manual downward movement using a handpiece (Group 1), vertical downward movement by CNC (Group 2), reciprocating up and down movement by CNC (Group 3), and spiral up and down movement by CNC (Group 4). In Experiment 2, five different insertion angles of the NiTi file were evaluated (n = 20). Four parameters were used to evaluate the shaping ability: change in the working length, central axis offset, curvature variation, and preparation time. Groups were compared using one-way analysis of variance (ANOVA) with significance was set at P

Objectives. The study aimed to establish correlations between implant geometry, bone density and survival rate of implant therapy. Material and method. The study material consisted of medical documents (clinical observation and treatment sheets, which included both the results of recommended laboratory tests, photographs and imaging investigations performed pre / intra / postoperatively) of patients who were addressed between October 1st, 2014 and October 1st, 2018 to the Oral Rehabilitation Clinic „Prof. Dr. Barbu“. The study included patients wearing mobilizable prostheses, with advanced periodontal diseases that required tooth extraction, patients who accepted dental implants as a treatment solution and presented at all scheduled sessions, including long-term post-therapeutic dispensary of at least 1 year. Statistical processing was performed with Microsoft Excel 2016. Results. The study group included 73 patients of both sexes (28 men and 45 women), old carriers of mobilizable prostheses, with severe periodontal diseases, which required dental extractions. 618 implants were inserted in the study group in order to prosthetic the edentulous gaps. Discussions. The study highlighted the high interest of females in the application of modern dental therapies. At the age group, the 50-59 age group was best represented, closely followed by the 40-49 age group. Most implants were inserted at the upper arch, at a right angle and were conical. Conclusions. Due to the lower bone density in the upper arch, 81.4% of failures occurred in the group studied in the jaw. Implants with small steps between turns have a better prognosis compared to implants with large steps between turns. From the point of view of the type of implant, the cylindrical-conical ones had the best prognosis, and the zygomatic ones registered the weakest prognosis. Bone additions were correlated with a higher failure rate (55.81% of cases). Implants inserted at 10˚ had the best survival rate, and those inserted at 35˚ and 55˚ had the lowest survival rate.

To evaluate the effect of the placement angle, diameter, length and bone density on the mechanical stability of orthodontic mini-implants by measuring their pull-out strengths. A total of 120 mini-implants of four different dimensions made from titanium were used. They measured 1.3 × 6.0mm, 1.3 × 8.0 mm, 1.5 × 6.0 mm and 1.5 × 8.0 mm. Synthetic polyurethane bone blocks (Saw Bones, USA) in two different densities were used. Each size of mini-implant was inserted equidistantly into synthetic bone blocks of two different densities, in three different insertion angles of 30°, 60° and 90°. This resulted in 24 test groups with five mini-implants allocated to each group. The pull-out strength was measured using an Instron Universal Testing Machine exerting a vertical force parallel to the long axis of the mini-implant until removal or failure occurred. Peak load at failure of the mini-implant was recorded in kN. Showed that mini-implants placed at an insertion angle of 30° offered least resistance to pull-out. Mini-implants 6.0 mm in length showed less pull-out strength compared to the longer 8.0-mm mini-implants. Mini-implants 1.3 mm in diameter provided similar pull-out values as 1.5-mm mini-implants. Bone densities of 0.20 g/cc and 0.32 g/cc did not affect the pull-out strength of mini-implants. From the study, it was concluded that a logical choice of mini-implant dimension and prudent use of placement technique can help achieve the treatment goals with a reduced hazard of mini-implant failure. [ABSTRACT FROM AUTHOR]

In recent years, various three-dimensional (3D) concrete printing (3DCP) systems have been developed extensively in the construction field. The extrusion-based 3DCP method using yield pseudoplastic mortar has emerged as the most promising system owing to its attractive properties. However, the poor bonding property of the interlayers brings cold joint-like gaps/voids, which decrease the mechanical properties of the printed elements. In this study, a novel reinforcing system was proposed for 3DCP-printed elements, in which metal fibers were inserted in the interlayers. Fundamental experiments were performed to verify the effectiveness of the proposed methods using different sizes and types of metal fibers. The results revealed that the tensile and flexural strengths of the printed elements improved when the reinforcing fibers were properly placed without air voids around the fibers. In addition, it was found that straight-shaped fibers were more suitable reinforcing fibers for avoiding voids. [ABSTRACT FROM AUTHOR]

Background. The present study aimed to assess the stress and strain distribution on mini-screws and the surrounding bone in cases of different cortical bone thicknesses (CBTs), mini-screw insertion angles, and force directions using finite element analysis (FEA). Methods. Inventor professional version 8 software was used to construct 24 three-dimensional assemblies of mini-screws inserted with different insertion angles (30°, 60°, and 90°) in alveolar bone blocks with different CBTs (0.5, 1, 1.5, and 2 mm). The models simulated mini-screws inserted in bones with different CBTs and different insertion angles. A 2-N load was applied in two directions to mini-screw heads. The resultant stresses of the applied load were collected from the output of the ANSYS program. Results. The results indicated that force direction affected bone strains as the horizontal force generated more strains on cortical bone than the oblique one. Force applied to 60° inserted mini-screws generated much more strains on cortical bone than 90° and 30° inserted miniscrews. In a 60° inserted mini-screw, the horizontal force generated about 45% more strains on cortical bone than the oblique one. The exerted microstrain on bone decreased as CBT increased. Conclusion. It can be concluded that inserting mini-screws at 60° to the bone surface should be avoided as it generates much more strains on cortical bone than 90° and 30°, especially when a force parallel to the bone surface is applied. [ABSTRACT FROM AUTHOR]

Study Design Four orthopedic spine surgeons measured the radiological parameters of pedicle screws in the cervical spine using a postoperative computed tomography (CT) scan. Purpose This study analyzed the insertion angle of CT-navigated insertion of pedicle screws in the subaxial cervical spine and classified them according to their position. Overview of Literature Overall, a pedicle transverse angle of 33.6°–50.2° with a mean angle of 45° relative to the midline has been reported in the literature. Methods The insertion angles of 87 pedicle screws inserted using CT-based navigation in the subaxial cervical spine were measured in the postoperative CT. The screw positioning was determined according to the modified Gertzbein and Robbins classification. Results Total 89.3% (n=78) of the pedicle screws inserted using CT-based navigation showed good placement. The mean insertion angle of the pedicle screws that showed good positioning was 29.9°±9.9°. The pedicle screws showing bad positioning had a mean insertion angle of 26.8°±10.5° (p=0.157). The interobserver reliability showed a reliable measurement intraclass correlation coefficient: 0.994 (95% confidence interval, 0.992–0.996). Conclusions The present results show that the insertion angle of the pedicle screws in the subaxial cervical spine was smaller than the actual pedicle transverse angle, as per the literature. One reason for this discrepancy could be that the navigation systems allow the insertion of cervical pedicle screws with a lower convergence.

Abstract Background The optimal insertion angle for suture anchor insertion has long been of great interest. Although greater tuberosity decortication is commonly performed during rotator cuff repair, the effect of decortication on the suture anchor insertion angle remains unclear. The purpose of this study was to compare the pullout strength of threaded suture anchors inserted at 45° and 90° in decorticated and non-decorticated synthetic bone models. Methods Two kinds of synthetic bones were used to simulate the decorticated and non-decorticated conditions, for which 40 metallic suture anchors were used. Anchors were inserted at 45° and 90° in both decorticated and non-decorticated models and tested under cyclic loading followed by load-to-failure testing. The number of completed cycles, ultimate failure load, and failure modes was recorded. Results In the decorticated model, the ultimate failure load of anchors inserted at 45° (67.5 ± 5.3 N) was significantly lower than that of anchors inserted at 90° (114.1 ± 9.8 N) (p

Background: To investigate the efficacy of a nickel-titanium (NiTi) file with an automated computerized numerical control (CNC) system for root canal shaping. Methods: The movement of the automated device and the insertion angle were investigated. In Experiment 1, simulated resin root canals were randomly divided into four groups (n = 20): manual downward movement using a handpiece (Group 1), vertical downward movement by CNC (Group 2), reciprocating up and down movement by CNC (Group 3), and spiral up and down movement by CNC (Group 4). In Experiment 2, five different insertion angles of the NiTi file were evaluated (n = 20). Four parameters were used to evaluate the shaping ability: change in the working length, central axis offset, curvature variation, and preparation time. Groups were compared using one-way analysis of variance (ANOVA) with significance was set at P < 0.05. Results: The change in central axis position in the curved part of the root canal was found to be smaller in Group 4 than in other groups (P < 0.05). The curvature changes and preparation time of Groups 1 and 4 were significantly reduced compared with Groups 2 and 3 (P < 0.05). The variation in working length and curvature in the 5° insertion angle group was significantly smaller than in the other groups (P < 0.05). Conclusions: A spiral up and down movement, controlled by the CNC machine, and 5° insertion angle, maintained original root canal shape more precisely than other methods. [ABSTRACT FROM AUTHOR]

We aimed to elucidate stress distribution in miniscrews and the surrounding bone when miniscrews inserted at different depths were implanted vertically or obliquely. The distributions of the equivalent stress on the screw surface and the minimum principal stress in the surrounding bone were calculated using finite element models. When the miniscrews were inserted vertically and obliquely, screw head displacement, greatest equivalent stress on the miniscrew surface, and absolute value of minimum principal stresses in the surrounding bone decreased with increasing insertion depth. Stresses in the obliquely inserted miniscrew with upward traction were smaller than in other insertion conditions, irrespective of insertion depth. With the application of orthodontic force, stress distribution around the miniscrew and surrounding bone is closely related to the insertion depth and insertion angle, which mutually affect each other. In particular, the obliquely inserted miniscrew with upward traction might be the most secure against screw failure and fracture. [ABSTRACT FROM AUTHOR]

Background: After introducing the first Cochlear Implants also in children theses are grown with electrical intracochlear stimulation and subsequent auditory cortical development. Over the meantime the positioning of the electrode was changed orientated on the development of electrode design, ability to insert atraumatic and on the widening of the indications towards highfrequency deafness. Methods: In this pilot study we analysed five prelingually deafened patients implanted as child in the late 90's and had a reimplantation 2016 or later. We compared CT and DVT (cone beam CT) scans of the temporal bone and measured the insertion angle, the cochlear coverage, the total length of the electrode in the cochlea and the distance of the first active electrode to the round window. Moreover, we compared their speech understanding before and after reimplantation. Results: The results show a lowering in the insertion angle, the cochlear coverage, the total length of the electrode in the cochlea, in the distance of the first active electrode to the round window and in the speech understanding after reimplantation. Conclusion: These results show a difference in the depth of insertion while the speech understanding is not significantly improving in this group—although the technology is advanced. The influence of auditory maturation with CI in these patients will be discussed. [ABSTRACT FROM AUTHOR]

Study Design: Four orthopedic spine surgeons measured the radiological parameters of pedicle screws in the cervical spine using apostoperative computed tomography (CT) scan. Purpose: This study analyzed the insertion angle of CT-navigated insertion of pedicle screws in the subaxial cervical spine and classified them according to their position. Overview of Literature: Overall, a pedicle transverse angle of 33.6°-50.2° with a mean angle of 45° relative to the midline has been reported in the literature. Methods: The insertion angles of 87 pedicle screws inserted using CT-based navigation in the subaxial cervical spine were measured in the postoperative CT. The screw positioning was determined according to the modified Gertzbein and Robbins classification. Results: Total 89.3% (n=78) of the pedicle screws inserted using CT-based navigation showed good placement. The mean insertion angle of the pedicle screws that showed good positioning was 29.9°±9.9°. The pedicle screws showing bad positioning had a mean insertion angle of 26.8°±10.5° (p =0.157). The interobserver reliability showed a reliable measurement intraclass correlation coefficient: 0.994 (95% confidence interval, 0.992-0.996). Conclusions: The present results show that the insertion angle of the pedicle screws in the subaxial cervical spine was smaller than the actual pedicle transverse angle, as per the literature. One reason for this discrepancy could be that the navigation systems allow the insertion of cervical pedicle screws with a lower convergence. [ABSTRACT FROM AUTHOR]

Background: The development of accurate in vitro—in vivo correlations requires the consideration of a number of factors in vitro, including the emulation of upper airway geometry, inhalation maneuver, inhaler orientation, and environmental conditions. In this study, we examine the effects of inhaler insertion angle and humidity on deposition from a number of marketed inhalers. Methods: Three dry-powder inhalers (DPIs; Pulmicort® Turbuhaler®, Budelin® Novolizer®, and Easyhaler® Budesonide) were examined at two insertion angles, one with the inhaler directed toward the back of the oral cavity, the other with the inhaler directed toward the tongue. Three pressurized metered-dose inhalers (pMDIs; QVAR®, Ventolin® Evohaler®, and Flovent® HFA) were examined considering the joint effects of insertion angle (as above) and relative humidity at low (15%–25%) and high (>95%) conditions. Deposited drug masses in an Alberta Idealized Throat and downstream filter were quantified through ultraviolet spectroscopy. Results and Conclusions: Three of six inhalers showed sensitivity to insertion angle. When directed toward the tongue versus the back of the mouth, the filter dose decreased from 21.9% to 15.6% (percent delivered dose) for Easyhaler Budesonide (p < 0.001), from 46.5% to 26.0% for Ventolin Evohaler (p < 0.001), and from 56.7% to 35.7% for Flovent HFA (p < 0.001) for tests at ambient laboratory humidity. Sensitivity to insertion angle and increases in total lung dose variability may be reduced in future products using larger diameter mouthpieces and smaller particles for DPIs and lower-momentum sprays for pMDIs. Humidity influenced deposition from Ventolin Evohaler and Flovent HFA. When oriented toward the back of the oral cavity, the filter dose decreased from 46.5% to 36.9% for Ventolin Evohaler (p = 0.005) and from 56.7% to 44.2% for Flovent HFA (p < 0.001) at high humidity relative to low. High humidity may cause a reduction in total in vitro lung doses for some pMDI aerosols. [ABSTRACT FROM AUTHOR]

In this paper, the interactive action between minimally invasive surgical suture needle and soft tissue was investigated under different insertion velocities, needle geometries, insertion angles and tissue characteristics to simulate the real surgical suture needle-tissue operation conditions. Experimental results demonstrated that the process of insertion was divided into two phases: no break phase and break phase. The puncture force generated at the mutation point where the tissue surface was breached. The puncture force and time for the first puncture significantly decreased with the increasing insertion velocity. The needle with triangle cross-section tip and larger size showed higher puncture force than that with round cross-section and smaller one. The penetration force reduced evidently with the advancing insertion angle, and it reached the lowest value when the angle is 90°. Moreover, an empirical single-parameter model of third-degree polynomial could predict the stiffness when a suture needle inserted into a complex soft tissue and showed a good fit to the experiment data. The results would provide reliable and significant mechanical database for the design of force feedback system in the surgical suture, either in endoscopic surgery or robotic suturing.

StereoElectroEncephaloGraphy (SEEG) is a minimally invasive technique that consists of the insertion of multiple intracranial electrodes to precisely identify the epileptogenic focus. The planning of electrode trajectories is a cumbersome and time-consuming task. Current approaches to support the planning focus on electrode trajectory optimisation based on geometrical constraints but are not helpful to produce an initial electrode set to begin with the planning procedure. In this work, the authors propose a methodology that analyses retrospective planning data and builds a set of average trajectories, representing the practice of a clinical centre, which can be mapped to a new patient to initialise planning procedure. They collected and analysed the data from 75 anonymised patients, obtaining 30 exploratory patterns and 61 mean trajectories in an average brain space. A preliminary validation on a test set showed that they were able to correctly map 90% of those trajectories and, after optimisation, they have comparable or better values than manual trajectories in terms of distance from vessels and insertion angle. Finally, by detecting and analysing similar plans, they were able to identify eight planning strategies, which represent the main tailored sets of trajectories that neurosurgeons used to deal with the different patient cases.

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Background: Pedicle screw instrumentation is one of the most commonly used forms of stabilization. Achieving solid screw fixation within the bone presents a significant challenge to spinal surgeons. Although pure pullout is not the mode of failure seen in clinical situations, pullout testing is thought to be a good predictor of pedicle screw fixation strength for spinal fusion. Objectives: To investigate the effects of varying lengths and thread depths of pedicle screws, as well as its insertion angle relative to the sagittal line on pullout strength, and stiffness of the pedicle screws and adjacent bone. Methods: Six fresh-frozen bovine lumbar vertebrae (L5) were examined. Pedicle screws with the lengths of 35, 40, and 45 mm, and the pedicle screws with thread depths of 0.9, 1.1, and 1.15 mm were inserted in pedicles by an orthopedic surgeon. Axial pullout tests were performed by a pullout apparatus and force-displacement curves were plotted. Results: The 45 mm length screw showed the maximum pullout strength (1746 N) and stiffness (564.7 N/mm) in the case of constant thread depth of 0.9 mm. The 1.15 mm thread depth screw showed the maximum pullout strength (1719 N) and stiffness (646.4 N/mm) in the case of constant length of 40 mm, and the screw insertion angle of 25° resulted in maximum pullout strength (1251 N) and stiffness (249.6 N/mm) in the case of constant thread depth of 0.9 mm and constant length of 35 mm. Conclusions: Increasing the length and the thread depth of the screws leads to an increase in the pullout strength, as well as the bone-screw construct stiffness. Pedicle screw pullout strength and the bone-screw construct stiffness were also affected by the insertion angle of the screw. There are other factors such as the insertion technique employed by the surgeon, and bone mineral density, which affect the pullout strength.

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Objective: The suitable electrode array choice is broadly discussed in cochlear implantation surgery. Whether to use a shorter electrode length under the aim of structure preservation versus choosing a longer array to achieve a greater cochlear coverage is a matter of debate. The aim of this review is to identify the impact of the insertion depth of a cochlear implant (CI) electrode array on CI users' speech perception outcomes., Databases Reviewed: PubMed was searched for English-language articles that were published in a peer-reviewed journal from 1997 to 2022., Methods: A systematic electronic search of the literature was carried out using PubMed to find relevant literature on the impact of insertion depth on speech perception. The review was conducted according to the preferred reporting items for systematic reviews and meta-analyses guidelines of reporting. Studies in both, children and adults with pre- or postlingual hearing loss, implanted with a CI were included in this study. Articles written in languages other than English, literature reviews, meta-analyses, animal studies, histopathological studies, or studies pertaining exclusively to imaging modalities without reporting correlations between insertion depth and speech outcomes were excluded. The risk of bias was determined using the "Risk of Bias in Nonrandomized Studies of Interventions" tool. Articles were extracted by 2 authors independently using predefined search terms. The titles and abstracts were screened manually to identify studies that potentially meet the inclusion criteria. The extracted information included: the study population, type of hearing loss, outcomes reported, devices used, speech perception outcomes, insertion depth (linear insertion depth and/or the angular insertion depth), and correlation between insertion depth and the speech perception outcomes., Results: A total of 215 relevant studies were assessed for eligibility. Twenty-three studies met the inclusion criteria and were analyzed further. Seven studies found no significant correlation between insertion depth and speech perception outcomes. Fifteen found either a significant positive correlation or a positive effect between insertion depth and speech perception. Only 1 study found a significant negative correlation between insertion depth and speech perception outcomes., Conclusion: Although most studies reported a positive effect of insertion depth on speech perception outcomes, one-third of the identified studies reported no correlation. Thus, the insertion depth must be considered as a contributing factor to speech perception rather than as a major decisive criterion., Registration: This review has been registered in PROSPERO, the international prospective register of systematic reviews (CRD42021257547), available at https://www.crd.york.ac.uk/PROSPERO/., Competing Interests: None declared., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of Otology & Neurotology, Inc.)

Aims: To determine whether obliquely inserted mini-implants can be loaded immediately with light orthodontic force? And which mini-implants are more stable those with 90 degree or 60 degree insertion angles? Materials and Methods: three rabbits were used in this study. Sixteen mini-implants divided into 2 groups equally. The first group implanted in the rabbit’s tibia bone at 90 degree insertion angle and the second group implanted in the rabbit’s tibia bone at 60 degree insertion angle. The stability of mini-implants was measured using periotest device immediately before and after loading and after 2 weeks of loading period. The data were analyzed using descriptive statistic, Analysis of variance (ANOVA), Duncan Multiple analysis range test and student t-test. Result: mini-implants at 60 degree insertion angle can be loaded immediately with light orthodontic force. Also, those miniimplants having a significant greater stability before loading and after two weeks of loading period in comparison with mini-implants implanted at 90 degree angle. Conclusions: In clinical practice, miniimplants inclined to the bone surface at 60degree tend to have better primary stability and can be loaded immediately.

Objectives To assess the feasibility of using cone-beam computed tomography (CBCT) in young children with cochlear implants (CIs) and study the effect of intracochlear position on electrophysiological and behavioral measurements. Methods A total of 40 children with either unilateral or bilateral cochlear implants were prospectively included in the study. Electrode placement and insertion angles were studied in 55 Cochlear ® implants (16 straight arrays and 39 perimodiolar arrays), using either CBCT or X-ray imaging. CBCT or X-ray imaging were scheduled when the children were leaving the recovery room. We recorded intraoperative and postoperative neural response telemetry threshold (T-NRT) values, intraoperative and postoperative electrode impedance values, as well as behavioral T (threshold) and C (comfort) levels on electrodes 1, 5, 10, 15 and 20. Results CBCT imaging was feasible without any sedation in 24 children (60%). Accidental scala vestibuli insertion was observed in 3 out of 24 implants as assessed by CBCT. The mean insertion angle was 339.7°±35.8°. The use of a perimodiolar array led to higher angles of insertion, lower postoperative T-NRT, as well as decreased behavioral T and C levels. We found no significant effect of either electrode array position or angle of insertion on electrophysiological data. Conclusion CBCT appears to be a reliable tool for anatomical assessment of young children with CIs. Intracochlear position had no significant effect on the electrically evoked compound action potential (ECAP) threshold. Our CBCT protocol must be improved to increase the rate of successful investigations. [ABSTRACT FROM AUTHOR]

Purpose: Anterior cervical discectomy and fusion is a common surgical procedure performed to remove a degenerative or herniated disc in cervical spine. Unfortunately, clinical complications of anterior cervical plate (ACP) systems still occur, such as weak fixation stability and implant loosening. Previous researchers have attempted to ameliorate these complications by varying screw orientations, but the screw orientations are mainly determined according to the investigator's experiences. Thus, the aim of this study was to discover the optimal screw orientations of ACP systems to achieve acceptable fixation stability using finite element simulations and engineering algorithms. Methods: Three-dimensional finite element models of C3-T2 multi-level segments with an ACP system were first developed to analyze the fixation stability using ANSYS Workbench 14.5. Then, artificial neural networks were applied to create one objective function, and the optimal screw orientations of an ACP system were discovered by genetic algorithms. Finally, the numerical models and the optimization study were validated using biomechanical tests. Results: The results showed that the optimal design of the ACP system had highest fixation stability compared with other ACP designs. The neuro-genetic algorithm has effectively reduced the time and effort required for discovering for the optimal screw orientations of an ACP system. Conclusions: The optimum screw orientation of the ACP system could be successfully discovered, and it revealed excellent fixation stability for the treatment of cervical degenerative disc disease. This study could directly provide the biomechanical rationale and surgical suggestion to orthopedic surgeons. [ABSTRACT FROM AUTHOR]

This study explored the inter-radicular space and buccal bone thickness of the posterior mandibular region to provide an appropriate miniscrew insertion site for lower dentition distalization. The cone-beam computed tomographic (CBCT) records of 63 subjects were collected. Buccal bone thickness (BBT) was measured at four sections: (I) the root of the second premolar(P 1); (II) the mesial root of the first molar(P 2); (III) the distal root of the first molar(P 3); (IV) the mesial root of the second molar(P 4). The narrowest inter-radicular space of the four sections was also detected. Both BBT and inter-radicular space were measured at 4 height levels, 2, 4, 6 and 8 mm from the alveolar ridge. The largest BBT was observed at the mesial root of the second molar at 6 and 8 mm, demonstrating a thickness of 6.77 ± 2.50 mm and 7.46 ± 1.94 mm, respectively. It provided sufficient coverage for mini-implants inserted 10°− 30° oblique to the root. Therefore, during distalization of the mandibular dentition, roots have sufficient space to bypass the inclined mini-implants on the lingual side, avoiding miniscrew-root contact. The width between the mesiodistal roots of the first molar was the smallest, showing 1.53 ± 0.69 mm and 2.13 ± 0.65 mm at 4 and 6 mm. Miniscrews implanted in this region had an increased risk of root proximity. The most appropriate insertion site at the mandibular buccal shelf was the mesial point of the second molar at 6–8 mm from the alveolar ridge, and an insertion angle of 10°− 30° was recommended to avoid miniscrew-root contact. CBCT analysis is recommended before implantation due to individual differences. [ABSTRACT FROM AUTHOR]