Insertion Angle Research Articles

Influence of external insert angle on structural deformation of long pipe shed with shallow hole

The long pipe shed advanced support has the characteristics of large construction difficulty, wide support range, and easy deviation. The difference in construction dip angle will produce a different plastic zone of surrounding rock and supporting effects, and the rationality of advanced support design plays an important role in the safety of tunnel opening excavation. Based on the Tianshan Tunnel project, this paper aims at the problems of the loose pebble layer structure, poor cohesion, strong permeability, shallow excavation is not easy to form a confined arch, and easy to causes surrounding rock deformation and failure. Combined with the new method theory, the finite difference software FLAC3D was used to simulate seven excavation schemes of the shallow tunnel entrances. The mechanism and effect of advance support and the influence of construction angle on support effect are analyzed, and the simulation values are compared with the measured data. The results show that using long pipe shed advanced support can effectively reduce the disturbance of excavation to lose pebble rock mass and reduce the convergence value of surrounding rock. The plastic zone of surrounding rock produced by different angles can be divided into three parts. The structural stability difference of the C1 zone is small, and that of the C3 zone is large. The bending moment, shear force, and shape variables of the pipe shed decrease with the increase of the dip angle, while the axial force increases with the increase of the dip angle. According to the similarity between the simulated curve and the measured curve, the best supporting effect can be achieved when the dip angle of the pre-supporting pipe shed is set in the range of 0° ~ 3°.

Effect of screw insertion angle and speed on the incidence of transcortical fracture development in a canine tibial diaphyseal model.

To assess the incidence of transcortical fracture (TCF) development based on screw insertion angle and screw insertion speed. Cadaveric experimental study. Sixty-six canine tibiae. Sixty-six cadaveric tibiae were randomly assigned to one of six groups that varied based on screw insertion angle relative to the pilot hole (0, 5, or 10°) and screw insertion speed (650 or 1350 revolutions per minute [rpm]). Each tibia was mounted in a custom jig. Locking self-tapping screws (3.5 mm) were inserted at varying speeds and insertion angles, based on group assignment. Orthogonal radiographs were evaluated for TCFs. Fisher's exact tests with a Bonferroni correction were performed to evaluate differences in the frequency of TCF between groups. In Group A (0°/650 rpm: control), a 0% TCF rate was observed (n = 0/80). Group B (5°/650 rpm) had a 3.75% TCF rate (n = 3/80). Group C (10°/650 rpm) had a 12.5% TCF rate (n = 10/80). Group D (10°/hand insertion) had a 3.75% TCF rate (n = 3/80). Group E (10°/1350 rpm) had a 17.5% TCF rate (n = 14/80). Group F (0°/1350 rpm) had a 0% TCF rate (n = 0/80). Groups C and E had the highest TCF rates with a difference in TCF rates observed between the control group and Group C (p = .001) and between the control group and Group E (p < .001). Increased screw insertion angle and insertion speed appear to be predisposing factors for TCF development in cadaveric bone. Ensuring screw insertion is coaxial with the pilot hole and using slower screw insertion speeds may help reduce the risk of TCF development.

Analysis on key parameters in subretinal injection facilitating a predictable and automated robot-assisted treatment in gene therapy.

Subretinal injection (SRI) has become an important surgical method for treating vitreoretinal diseases. Nevertheless, the optimisation of bleb formation in SRI, for the attainment of desired therapeutic outcomes, still requires further investigation. This study analysed the influence of surgical parameters on SRI using a robotic setup. The surgical procedure was automated using visual guidance. A predictive model for bleb formation was established through regression analysis. To validate the model, we compared the clinical data's target area with the simulated SRI's actual area using parameters determined by the predictive model. The insertion angle dominated the eccentricity and area of the bleb. The injection speed dominated the axial angle. Automated SRI increased success rate and produced predictable outcomes. We could provide accurate SRI on phantom models by adjusting surgical parameters based on the patient's clinical information. Automatic robot-assisted SRI is a promising surgical technique with highly predictable results.

Ultrasonographic examination of the safe zone for medial needle approach towards the median-innervated flexor digitorum profundus muscle: Effect of changes in position of the forearm.

The flexor digitorum profundus (FDP) is a forearm flexor muscle. Certain cases require the needle to be inserted accurately and safely into the deep, lateral portion of the FDP, which is innervated by the anterior interosseous nerve. In this study, we compared 2 techniques for approaching the median-innervated FDP (MFDP) medially, each according to the position of the forearm, supinated or pronated. The forearms of healthy volunteers without any musculoskeletal problems of the upper extremities were examined. Using high-resolution ultrasonography, the medial aspects of the forearms were scanned with elbows flexed at 90°. Using the images obtained, several parameters for distance and angle were measured in 2 different positions: forearm-supinated and forearm-pronated. Thirty-seven forearms from the volunteers were subject to examination. The angle α, which is the valid angle of insertion when approaching with the needle towards the deeply located MFDP, slightly increased from 22.89° to 23.41° when the forearm was pronated from the supinated position; however, this increase was not statistically significant. In contrast, the angle β, which is the safe angle of insertion when approaching with the needle towards the MFDP without contacting the ulnar nerve, was significantly increased from 41.40° to 46.80° upon forearm pronation. Because the safe angle of insertion of the needle medially into the MFDP increases with forearm pronation, the forearm-pronated position is recommended, instead of the forearm-supinated position, when inserting a needle into the MFDP in the medial aspect of the forearm.

Accuracy of Preoperative Cochlear Duct Length Estimation and Angular Insertion Depth Prediction.

In cochlear implantation with flexible lateral wall electrodes, a cochlear coverage of 70% to 80% is assumed to yield an optimal speech perception. Therefore, fitting the cochlear implant (CI) to the patient's individual anatomy has gained importance in recent years. For these reasons, the optimal angular insertion depth (AID) has to be calculated before cochlear implantation. One CI manufacturer offers a software that allows to visualize the AID of different electrode arrays. Here, it is hypothesized that these preoperative AID models overestimate the postoperatively measured insertion angle. This study aims to investigate the agreement between preoperatively estimated and postoperatively measured AID. Retrospective cross-sectional study. Single-center tertiary referral center. Patients undergoing cochlear implantation. Preoperative and postoperative high-resolution computed tomography (HRCT). The cochlear duct length was estimated by determining cochlear parameters ( A value and B value), and the AID for the chosen electrode was (i) estimated by elliptic circular approximation by the software and (ii) measured manually postoperatively by detecting the electrode contacts after insertion. A total of 80 HRCT imaging data sets from 69 patients were analyzed. The mean preoperative AID estimation was 662.0° (standard deviation [SD], 61.5°), and the mean postoperatively measured AID was 583.9° (SD, 73.6°). In all cases (100%), preoperative AID estimation significantly overestimated the postoperative determined insertion angle (mean difference, 38.1°). A correcting factor of 5% on preoperative AID estimation dissolves these differences. The use of an electrode visualization tool may lead to shorter electrode array choices because of an overestimation of the insertion angle. Applying a correction factor of 0.95 on preoperative AID estimation is recommended.

The success rate of mini-screws for incisors intrusion and patient age, gender, and insertion angle in the maxilla using CBCT and implant-guided surgery. A split-mouth, randomized control trail.

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. 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. 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. This study found that male patients with mini-screws inserted at 90° showed greater screw stability over time.

Usefulness of intraoperative optical coherence tomography to minimize the intraocular lens tilt during the intrascleral fixation: a clinical and experimental evaluation

To report the usefulness of intraoperative real-time adjustment of intraocular lens (IOL) tilt during the intrascleral fixation with intraoperative optical coherence tomography (iOCT) as a clinical evaluation and investigate the factors contributing to IOL tilt using iOCT as an experimental evaluation. Retrospective cohort study and experimental research. As a clinical evaluation, the medical records of 43 eyes of 41 patients who underwent intrascleral IOL fixation combined with real-time iOCT observation were retrospectively reviewed. As an experimental evaluation, in order to investigate the factors contributing to IOL tilt, the four experiments were performed using iOCT. The mean IOL tilt angle (°) at the end of surgery and 3 months after surgery were 1.81 ± 1.15 and 2.10 ± 1.66, respectively (p = 0.46). No apparent intra- or postoperative complications occurred during the follow-up period. The experimental evaluation indicated that the IOL tilt was influenced by the insertion angle of the haptic in the vertical direction. The mean IOL tilt angle (°) was 1.94 ± 0.09, 4.67 ± 0.11, 8.90 ± 0.11, and 15.78 ± 0.85 when the insertion angle of the haptic was 0°, 10°, 27.5°, and 45° in the vertical direction, respectively (p < 0.01). Clinical and experimental IOL tilt assessment using iOCT is interactively useful for better quality surgery and better postoperative outcome.

Pterygoid and tuberosity implants in the atrophic posterior maxilla: A retrospective cohort study

Statement of problemRehabilitation of the partially or completely edentulous posterior maxilla using dental implants is a clinical challenge because of the presence of the maxillary sinus, as well as the low quality and quantity of bone in that region. In addition to bone augmentation procedures, posterior maxillary rehabilitation using implants includes their anchoring in bones such as the zygoma, pterygoid, and maxillary tuberosity, as well as in short implants. However, the performance of pterygoid and tuberosity implants in the atrophic posterior maxilla is unclear. PurposeThe purpose of this retrospective cohort study was to evaluate the survival of tuberosity and pterygoid implants in patients with posterior maxillary atrophy. Material and methodsA nonprobability convenient sample of patients who had received fixed prostheses on implants placed in the maxillary tuberosity or pterygoid regions was analyzed retrospectively. Demographic variables included sex (male, female) and age. Implant-related variables included surface characteristics, site of placement, implant design, length, diameter, and anteroposterior insertion angle. Prosthetic-related variables included the type of reconstruction for rehabilitation and loading protocols. Implant survival, complications, crestal bone loss, and follow-up intervals were also documented. Collected data were analyzed at both patient and implant levels. The demographics and implant characteristics of patients receiving pterygoid or tuberosity implants were analyzed with a statistical software program (α=.05). Survival analysis was estimated by using the nonparametric Kaplan-Meier curve. ResultsA total of 119 patients had 183 pterygoid or tuberosity implants inserted. Most implants in the pterygoid region (71.5%) were Ø4.1 mm (87.4%) and 15 mm in length (60.1%). The most common prostheses were complete maxillary reconstructions (49.2%) with late loading (74.3%). The average implant anteroposterior insertion angle was 60.8 degrees. The cumulative survival rate was 97.3% (n=178) during the mean follow-up period of 57 months (range 1 to 168 months). Among all implants placed, 2.7% failed (n=5) within 2 months of their placement. The statistically significant differences noted between tuberosity and pterygoid implants were related to design, surface characteristics, and loading. The average crestal bone loss was 1.5 mm. ConclusionsThe survival of the implants placed in the maxillary tuberosity and pterygoid regions was high in patients with posterior maxillary atrophy.

Development of a Base-Actuated Three-Rhombus Configured Remote Center of Motion Mechanism for Lumbar Puncture

Abstract Owing to the advantages of safety and reproducibility, remote center of motion (RCM) mechanisms are widely adopted in lumbar puncture (LP) procedures to guide the insertion angle and depth of the end effector. However, the proximal-actuated pattern in existing RCM mechanisms occupies a large space near the end effector, which obstructs the visual field and increases the system inertia. In this work, a base-actuated three-rhombus configured RCM mechanism for LP operation is first proposed, where the symmetric three-rhombus scheme is designed for motion transmission. As a result, the rotational and translational motions of the needle are respectively realized through the homodromous and heterodromous actuation of the two base-mounted motors. Kinematic models are established to analyze the manipulability, singularity, and workspace of the RCM mechanism theoretically. The parameter optimization procedure is provided to minimize the footprint of the RCM mechanism. Experimental results show that the mechanism reaches an insertion angle from −29.2 deg to 29.2 deg, a maximum insertion depth of 60.02 mm, and a footprint of 4.98 × 104 mm2. The relative error of the RCM point is 1.1 mm.

Proposing and thermo-economic optimization of an annular-thermoelectric gas heat recovery unit with a novel hybrid fin-pin vane and porous insert

Heat recovery from the cylindrical surface of the exhaust gas pipes is one of the promising applications of annular thermometric generators (ATEG). A pipe-shape based heat exchanger can be attached to the inner surface of the annular-thermoelectric generator to recover the hot exhaust gas in the form of electricity generation. In this paper, a novel grid annular fin-based heat exchanger with porous inserts is proposed which can boost the output power of the ATEG up to 1.45 and 2.12 times compared to the conventional common pipe-based heat exchangers. A comprehensive parametric analysis is carried out to investigate the impact of various geometric and operational parameters such as porous insert height, porous insert angle, porous inserts length, Re number, number of thermocouples, and so on thermal, exergetic, and economic factors. An optimized value of height, length, and angle of the porous insert can maximize the output power of the proposed system. Economic analysis is also provided to identify the corresponding costs of the grid annular fin-based heat exchanger with porous inserts for the heat recovery aim.

Analysis of applicator displacement in accelerated partial breast irradiation using a strut-based design brachytherapy applicator

PURPOSEThis study aimed to identify factors associated with strut-adjusted volume implant (SAVI) displacement in accelerated partial breast irradiation (APBI) using a SAVI device. METHODS AND MATERIALSWe retrospectively analyzed computed tomography scans taken at the time of treatment planning and immediately before treatment in 61 patients (median age; 55 years, range; 40–85) treated with SAVI and determined the amount of SAVI displacement that occurred between the time from planning to the treatment. The displacement was calculated for the CT axis and SAVI axis, which is related to the SAVI structure. To investigate the cause of the displacement, multivariate analysis was performed on the calculated standard deviation and the insertion angle of SAVI with respect to the sternum in each cross-section, breast density, amount of air around the SAVI, and SAVI length inside the patient to obtain the β coefficient (p-value). RESULTSOn the CT coordinate system, positive correlations were observed between the SAVI insertion angle and air volume in the lateral (β coefficient:0.255–0.483) and rotational directions (β coefficient:0.341). On the SAVI coordinate system, positive correlations were observed between the SAVI insertion angle and air volume in all lateral (β coefficient:0.270–0.354) and rotational directions (β coefficient:0.294). A negative correlation was observed between the SAVI length inside the patient and the rotational direction (β coefficient: −0.262). CONCLUSIONSAVI insertion angle, the amount of the air outside SAVI and SAVI insertion length are factors which affect the displacement of the applicator. From the results, the applicator displacement and rotation must be <3 mm and 10o in order to meet all the dose criteria. Thus, we should be aware of these factors during insertion of the device to avoid the problem in treatment delivery for the APBI.

Cochlear coverage with lateral wall cochlear implant electrode arrays affects post-operative speech recognition.

The goal was to investigate the relationship between the insertion angle/cochlear coverage of cochlear implant electrode arrays and post-operative speech recognition scores in a large cohort of patients implanted with lateral wall electrode arrays. Pre- and post-operative cone beam computed tomography scans of 154 ears implanted with lateral wall electrode arrays were evaluated. Traces of lateral wall and electrode arrays were combined into a virtual reconstruction of the implanted cochlea. This reconstruction was used to measure insertion angles and proportional cochlear coverage. Word recognition scores and sentence recognition scores measured 12 months after implantation using electric-only stimulation were used to examine the relationship between cochlear coverage/insertion angle and implantation outcomes. Post-operative word recognition scores and the difference between post- and pre-operative word recognition scores were positively correlated with both cochlear coverage and insertion angle, however sentence recognition scores were not. A group-wise comparison of word recognition scores revealed that patients with cochlear coverage below 70% performed significantly worse than patients with coverage between 79%-82% (p = 0.003). Performance of patients with coverage above 82% was on average poorer than between 79%-82, although this finding was not statistically significant (p = 0.84). Dividing the cohort into groups based on insertion angle quadrants revealed that word recognition scores were highest above 450° insertion angle, sentence recognition scores were highest between 450° and 630° and the difference between pre- and post-operative word recognition scores was largest between 540° and 630°, however none of these differences reached statistical significance. The results of this study show that cochlear coverage has an effect on post-operative word recognition abilities and the benefit patients receive from their implant. Generally, higher coverage led to better outcomes, however there were results indicating that insertion past 82% cochlear coverage may not provide an additional benefit for word recognition. These findings can be useful for choosing the optimal electrode array and thereby improving cochlear implantation outcomes on a patient-individual basis.

Leveraging ultrasonic actuation during inclined orthopaedic bone drilling: An experimental and histological study

The treatment of fractured bones imperatively requires an orthopaedic bone drilling procedure. During the drilling of fracture bone, induced cutting force and temperature elevation may affect the initial stability and pullout strength at the bone-screw interface. Rotary ultrasonic-assisted drilling is gaining high attention to promote initial holding strength by reducing thermal energy and induced cutting force. Therefore, the proposed work is focused to leverage ultrasonic actuation to elevate the pullout strength by mitigating induced cutting force and temperature rise at the drill site. The technique of ultrasonic-assisted drilling is compared with conventional drilling of porcine femur bones. The influence of different drilling parameters such as insertion angle, feedrate, rotational speed and ultrasonic amplitude was monitored on the output characteristics. The infrared thermal imaging technique and force dynamometer was used to monitor temperature elevations and induced force. An increase in induced cutting force was observed to surge thermal energy and microcracks that lead to temperature elevations. Moreover, higher temperature and cutting force resulting lower biomechanical pullout strength of orthopaedic bone screws. In order to evaluate the effects of heat generation on tissue damage, osteonecrosis and bone morphology, histopathological analysis was performed at the drilled sites. It was witnessed that ultrasonic-assisted drilling was associated with higher viable lacunes and filled osteocytes leading to greater cell viability compared to conventional drilling. The present work shed light on an ultrasonic-assisted drilling system that is essential for low-trauma surgeries for orthopaedic applications.

A Three-Dimensional Finite Element Analysis of the Stress Distribution Around the Bone Mini-Implant Interface Based on the Mini-Implant Angle of Insertion, Diameter, and Length.

Temporary anchorage devices or mini implants have gained great attraction due to their capability to provide absolute anchorage, low cost, versatility, and can be loaded immediately after placement. Finite element analysis was used to evaluate the distribution of stress at the bone mini implant interface based on different angles of insertion (30°, 45°, 60°, and 90°) mini implant diameter (1.3 mm, 1.6 mm, and 2 mm) and mini implant length (6 mm, 8 mm, and 10 mm). A retraction force of 2 N was applied. Areas of maximum stress concentration were the head and neck of the mini implant and cortical bone around the mini implant. A very minimal amount of stress was found in the cancellous bone. The maximum stress found in the cortical bone was 5.1301 MPa and in the mini implant was 26.355 MPa with an angle of insertion of 30°, a 1.3 mm diameter, and a 6 mm length. The minimum stress found in the cortical bone was 1.4702 MPa and that in the mini implant was 5.3895 MPa with an angle of insertion of 90°, a 2 mm diameter, and a 10 mm length. For maximum stability, mini implants should be placed at a perpendicular angle of insertion with sufficient diameter and length.

Progress on Kirschner wire insertion techniques for patellar fractures

Tension band wiring has been widely used in patellar fracture internal fixation. However, Kirschner wires (K-wires) insertion is time-consuming, because it requires multiple intraoperative fluoroscopies to adjust the insertion angle, and the accuracy of insertion is not ideal. In this review, we summarize the measurement of patellar anatomical parameters, K-wires placement level, and application of guiding devices, with the focus on improving the accuracy of K-wire insertion from perspectives of K-wire placement and guiding devices. This review hope to provide some inspiration for new guiding devices with auxiliary K-wire placement.

107-LB: Clinical Performance of Extended Mio 30 Infusion Set

Objective: Medtronic Mio™ 30 infusion set (M30IS) is a single use IS for pump users with pre-loaded inserter, a 30° insertion angle, and labeled for 3-day use. The M30IS wear duration is impacted by initial local trauma caused by insertion and sustained inflammation by cannula &amp; insulin infusion (insulin aggregates &amp; other impurities in the infusate), with the latter being predominant. An extended Mio™ 30 infusion set (EM30IS) was developed by improving insulin formulation stability in the fluid path. This study reports on the performance of the EM30IS in persons with T1D during an early feasibility trial (ClinicalTrials.gov: NCT05544643). Method: This is a X over study of EM30IS and M30IS on 21 subjects with type 1 diabetes. Each subject wore both sets 4-5 times each on a preferred site that was continuously infused with insulin lispro or aspart subcutaneously via a Medtronic 780G pump for 3 days (M30IS), 7 days (EM30IS) or until failure. Endpoints of safety and effectiveness (failure rate due to unexplained hyperglycemia &amp;lt;16%) were evaluated. Exploratory analyses related to performance and glycemic control were also evaluated. Results: The EM30IS survival rate at 6 days (70%) was comparable to M30IS survival rate at 3 days (63%). Glycemic control outcomes were equivalent (see Table 1) and there were no episodes of EM30IS-related severe hypoglycemia or DKA. Conclusion: The EM30IS was safe and its performance at 6 days was equivalent to the performance of M30IS at 3 days. Disclosure O. Cohen: Employee; Medtronic. Y. Cohen: None. S. Chattaraj: Employee; Medtronic. G. Zhang: Employee; Medtronic. E. Anselmo: Employee; Medtronic. A. Tirosh: Advisory Panel; Medtronic. Research Support; Medtronic. Speaker's Bureau; Medtronic. Advisory Panel; Novo Nordisk. Speaker's Bureau; Novo Nordisk. Advisory Panel; Sanofi. Speaker's Bureau; Sanofi. Research Support; Sanofi. Advisory Panel; Eli Lilly and Company. Speaker's Bureau; Eli Lilly and Company. Funding Medtronic

Machine learning and sensitivity analysis for predicting nasal drug delivery for targeted deposition

Targeted nasal drug delivery can provide improved efficacy for drug formulations to be delivered at high efficacy rates. Some parameters that influence drug delivery have a dependency on the patient’s technique of administration and the spray device itself. When the different parameters, each having a specific range of values are combined, the combinatory permutations for studying its effects on particle deposition become large.In this study, we combine six input spray parameters (the spray half-cone angle, the mean spray exit velocity, the breakup length from the nozzle exit, the diameter of the nozzle spray device, the particle size, and the sagittal angle of the spray) with a range of values to produce 384 combinations of spray characteristics. This was repeated for three inhalation flow rates of 20, 40, and 60 L/min.To reduce the computational costs of a full transient Large Eddy Simulation flow field, we create a time-averaged frozen field and perform the time integration of particle trajectories through the flow field to determine the particle deposition in four anatomical regions of the nasal cavity (anterior, middle, olfactory and posterior) for each of the 384 spray field.A sensitivity analysis determined the significance of each input variable on the deposition. It was found the particle size distribution significantly affected deposition in the olfactory and posterior regions, while the spray device insertion angle was significant for deposition in the anterior and middle regions.Five machine learning models were evaluated based on 384 cases and it was found that despite the small sample dataset the simulation data was sufficient to provide accurate machine-learning predictions.

Tsetse fly inspired steerable bone drill-a proof of concept.

The fixation strength of pedicle screws could be increased by fixating along the much stronger cortical bone layer, which is not possible with the current rigid and straight bone drills. Inspired by the tsetse fly, a single-plane steerable bone drill was developed. The drill has a flexible transmission using two stacked leaf springs such that the drill is flexible in one plane and can drill along the cortical bone layer utilizing wall guidance. A proof-of-principle experiment was performed which showed that the Tsetse Drill was able to successfully drill through 5, 10 and 15 PCF cancellous bone phantom which has similar mechanical properties to severe osteoporotic, osteoporotic and healthy cancellous bone. Furthermore, the Tsetse Drill was able to successfully steer and drill along the cortical wall utilizing wall guidance for an insertion angle of 5°, 10° and 15°. The experiments conclude that the tsetse fly-inspired drilling method is successful and even allows the drilling along the cortical bone layer. The Tsetse Drill can create curved tunnels utilizing wall guidance which could increase the fixation strength of bone anchors and limit the risk of cortical breach and damage to surrounding anatomy.

Reexamining the effects of electrode location on measures of neural health in cochlear implant users.

The electrically evoked compound action potentials (ECAPs) amplitude-growth function (AGF) slope correlates with spiral ganglion neuron (SGN) density in the cochlear implanted cochlea. Electrode insertion angle and medial-lateral distance covary from base to apex; in some human ears, SGN survival varies from base to apex, making it difficult to parse out contributing factors to the ECAP AGF slope. Evoked compound action potentials were analyzed on each electrode and compared to post-operative computerized tomography scans. When controlling for medial-lateral distance, insertion angle does not influence ECAP AGF slope.

MRI enhances the understanding of critical anatomy during primary laparoscopic port placement.

Despite the majority of laparoscopic visceral injuries occurring with primary entry, high-fidelity training models are lacking. Three healthy volunteers underwent non-contrast 3T MRI at Edinburgh Imaging. A direct entry 12mm trocar was filled with water to improve MR visibility, placed on the skin at entry points, then images were acquired in the supine position. Composite images were created, and distances from the trocar tip to the viscera were measured, demonstrating anatomical relationships during laparoscopic entry. With a BMI of 21 kg/m2, gentle downward pressure during skin incision or trocar entry reduced the distance to the aorta to less than the length of a No. 11 Scalpel blade (22mm). The need for counter-traction and stabilisation of the abdominal wall during incision and entry is demonstrated. With a BMI of 38 kg/m2, deviating from the vertical angle for trocar insertion can result in the entire trocar shaft being placed within the abdominal wall without entering the peritoneum, creating a 'failed entry.' At Palmer's point distance between the skin and bowel is only 20mm. Ensuring the stomach is not distended will minimise gastric injury risk. The use of MRI to provide visualisation of the critical anatomy during primary port entry allows the surgeon to gain better understanding of textually described best practice techniques.