Path Of Insertion Research Articles

Removable partial dentures: Part 3.

The provision of removable partial dentures (RPDs) is an important skill for practitioners and it can often be challenging to make a successful prosthesis which the patient finds satisfactory. This three-part series has been designed to provide an overview of the clinical management of patients requiring RPDs. This final part describes more complex techniques that may be faced by dentists with additional training or experience in fixed and removable prosthodontics. These scenarios include the use of precision attachments to provide additional retention for an RPD, swinglock dentures to aid retention in cases with unfavourable tooth or alveolar undercuts, and sectional dentures for patients with challenging paths of insertion. For each clinical technique, the advantages, disadvantages and indications are summarised.

Surface topography changes and wear resistance of different non-metallic telescopic crown attachment materials in implant retained overdenture (prospective comparative in vitro study)

BackgroundThe purpose of this study was to evaluate the effect of using different types of metallic and non-metallic telescopic crown attachment materials on wear resistance and surface tomography changes in implant-retained mandibular overdentures.Materials and methodsCompletely edentulous mandibular epoxy models were fabricated, in which two implants were placed in the canine region and retained to the implants with three different material combinations used for the construction of telescopic attachments. Thirty-three identical mandibular overdentures were fabricated using the conventional standardized technique. The study groups were divided into three categories according to the material used for the construction of the secondary copings. The primary copings in all the study groups were constructed of PEEK, while the secondary coping in group I was PEEK, group II was ZrO2 and CoCr for group III. Primary copings were cemented on a ready-made abutment. Secondary copings were placed over the primary copings in the desired path of insertion, then picked up into the intaglio surface of the overdentures. A cyclic loading machine was used to apply repeated insertion-removal cycles simulating nearly 10 years of clinical use. Stereomicroscope with a built-in camera was used to monitor the reduction in width of the primary copings to evaluate the wear resistance of each material combination.ResultsThere was highly statistically significant difference between the study groups after the application of 1.000, 5.000 and 10.000 cycles. The highest level of wear resistance was recorded for the PEEK/PEEK combination, whereas PEEK/ZrO2 and PEEK/CoCr showed no significant differences.ConclusionsImplant retained overdenture with PEEK-PEEK telescopic crown attachment is associated with the highest wear resistance among all the study groups. PEEK-PEEK combination may be the treatment of choice for fabrication of telescopic attachment in implant retained overdenture as it provides better resistance to wear. It offers the advantages for geriatric patients as it decreases the possibility for repeated repair and replacement of attachment, increase long-term patient satisfaction and shelf life of prosthesis.

A multi-constraint optimal puncture path planning algorithm for percutaneous interventional radiofrequency thermal fusion of the L5/S1 segments

To minimize variations in treatment outcomes of L5/S1 percutaneous intervertebral radiofrequency thermocoagulation (PIRFT) arising from physician proficiency and achieve precise quantitative risk assessment of the puncture paths. We used a self-developed deep neural network DWT-UNet for automatic segmentation of the magnetic resonance (MR) images of the L5/S1 segments into 7 key structures: L5, S1, Ilium, Disc, N5, Dura mater, and Skin, based on which a needle insertion path planning environment was modeled. Six hard constraints and 6 soft constraints were proposed based on clinical criteria for needle insertion, and the physician's experience was quantified into weights using the analytic hierarchy process and incorporated into the risk function for needle insertion paths to enhance individual case adaptability. By leveraging the proposed skin entry point sampling sub-algorithm and Kambin's triangle projection area sub-algorithm in conjunction with the analytic hierarchy process, and employing various technologies such as ray tracing, CPU multi-threading, and GPU parallel computing, a puncture path was calculated that not only met clinical hard constraints but also optimized the overall soft constraints. A surgical team conducted a subjective evaluation of the 21 needle puncture paths planned by the algorithm, and all the paths met the clinical requirements, with 95.24% of them rated excellent or good. Compared with the physician's planning results, the plans generated by the algorithm showed inferior DIlium, DS1, and Depth (P < 0.05) but much better DDura, DL5, DN5, and AKambin (P < 0.05). In the 21 cases, the planning time of the algorithm averaged 7.97±3.73 s, much shorter than that by the physicians (typically beyond 10 min). The multi-constraint optimal puncture path planning algorithm offers an efficient automated solution for PIRFT of the L5/S1 segments with great potentials for clinical application.

Beyond graduation: understanding professional downgrading in Moroccan vocational training alumni

PurposeYoung graduates in Morocco are encountering an increasingly challenging labor market environment. Confronted with intense competition, job insecurity, and unclear career trajectories, many find themselves in low-skilled positions despite possessing relevant qualifications. This issue is particularly pronounced among vocational training graduates, who experience professional downgrading at a rate three times higher (33.6%) compared to their peers from general education (11.6%) (HCP, 2018). Our study aims to investigate professional downgrading among young vocational training graduates in Morocco, focusing on the factors contributing to this phenomenon and identifying potential solutions to address it.Design/methodology/approachOur study is based on the insertion and career path survey conducted by the Department of Professional Training with graduates of professional training programs in Morocco. For this edition, the survey was conducted in 2020, encompassing all 31,498 graduates of the 2016 professional training programs. The Heckman self-selection model is employed to analyze and explore various dimensions of downgrading. Factors such as gender, age, marital status, parental education, and the choice of vocational training field are scrutinized to understand their influence on downgrading.FindingsThe study reveals several key findings: Women exhibit a lower probability of professional downgrading compared to men. Young graduates are more vulnerable to downgrading, emphasizing the necessity for career guidance and mentorship programs to facilitate their entry into the job market. Marital status plays a role, with married individuals having a higher likelihood of downgrading. Parental education, particularly that of mothers, proves critical in preventing subjective downgrading of vocational training graduates, highlighting the need for adult literacy and education programs. The effectiveness of the National Agency for the Promotion of Employment and Competencies (ANAPEC) programs in preventing downgrading among vocational training graduates is questioned, suggesting the need for program revisions tailored to this population. The choice of vocational training field significantly impacts downgrading, with graduates of technical training programs experiencing advantages. This emphasizes the importance of diversifying training fields and aligning them with market demands.Originality/valueThis study provides valuable insights into the phenomenon of professional downgrading among young vocational training graduates in Morocco. The findings emphasize the need for targeted policy interventions. Recommendations include supporting young graduates, reassessing programs offered by the ANAPEC, and enhancing technical training to better align with the evolving demands of the labor market.

Accuracy of Cervical Pedicle Screw Insertion With and Without a Navigation-Linked High-Speed Drill: A Retrospective Clinical Study.

Cervical pedicle screw (CPS) fixation provides high stability but poses a risk of nerve and vascular injury. Although useful for reducing CPS deviation rates, navigation systems cannot completely eliminate deviation. This study aimed to compare two methods for creating insertion paths, one using a navigation-linked high-speed drill (NAVI drill) and the other using conventional manual probing. Our study comprised 104 patients with 509 CPSs at the C3-6 level who were treated at our institution between 2017 and 2023. CPS deviations were graded according to the Neo classification system, and the deviation direction (medial, lateral, cranial, or caudal) was assessed. Complications associated with CPS deviation were also investigated. We compared cases that used the NAVI drill (Group M) with those that used manual probing (Group N). Group M included 45 cases (252 screws), and Group N included 59 cases (257 screws). The CPS deviation rate was grade 1 or higher in 14.7% and 17.1% of cases in Groups M and N, respectively (p = 0.469). It was grade 2 or higher in 1.2% and 4.3% of cases in Groups M and N, respectively (p = 0.222). The medial, lateral, caudal, and cranial deviation direction rates were 56.8%, 2.7%, 40.5%, and 0% in Group M and 13.6%, 72.7%, 11.4%, and2.3% in Group N, respectively (p < 0.001). In one case in Group N, a grade 3 lateral deviation resulted in vertebral artery injury (VAI). The use of the NAVI drill was associated with a slightly lower, albeit insignificant, CPS deviation rate. However, it significantly lowered the proportion of lateral deviations. Therefore, the NAVI drill is a useful tool for preventing VAI.

A cross-sectional CBCT assessment of the relative position of one-piece titanium-zirconium mini-implants placed for mandibular overdentures using non-guided surgery.

To assess the relative position of mini-implants to retain a mandibular overdenture, according to the surgical protocol, technical and anatomical factors. Mandibular cone-beam computed tomography (CBCT) scans were analyzed for 73 patients who received four one-piece titanium-zirconium mini-implants. Drilling was performed using a 1.6 mm needle drill and a 2.2 mm Pilot Drill, according to the bone density with a surgical stent. Post-insertion CBCT images in DICOM format were analyzed using the E-Vol-DX software with BAR filters. Divergence angle between implants and between implants and the overdenture path of insertion was measured using CliniView 10.2.6 software. Divergence between implants ranged from 0° to 22.3° (mean = 4.2; SD = 3.7) in the lateral and from 0° to 26.2° (mean = 5.3; SD = 4.1) in the frontal projections (p < .001). Only 1 (0.2%) and 3 (0.7%) of the measurements were higher than 20° in the lateral and frontal views, respectively. The mean angulations between the implant and the path of insertion for the overdenture were 9.3° (SD = 7.5) and 4.0° (SD = 2.9) for the lateral and frontal views, respectively (p < .001). Regression analyses showed a significant association between the divergence of implants and the frontal view projection (p < .001), greater distance between the paired implants (p = .017), the flapped surgical protocol (p = .002), higher final insertion torque (p = .011), and deeper preparation with the needle drill (p < .001). The mini-implants were placed with low divergence angles and satisfactory parallelism. Factors including shorter distances between the implants, higher density bone, and a flapless surgical approach all contributed positively to improved parallelism of the mini-implants.

New adhesive rehabilitation technique with indexed occlusal tabletops made by 3D printing technology.

In oral rehabilitation, a full mouth minimal invasive treatment can represent a major challenge for the patient and the dentist. The purpose of this article is to present a new technique to restore eroded teeth and recover the vertical dimension with a simple and predictable technique. Occlusal tabletop restorations are a suitable conservative option to restore anatomy and vertical dimension augmentation but highly sensitive. The cementation of those restorations without stable landmarks, the cement excess removal, the insertion path, or the time needed are some of the difficulties can be faced. Now a days with the new CAD-CAM techniques is possible to develop a new occlusal tabletop manufacturing alternative utilizing 3D-printed technology by unifying the restorations with a customized connector that allows us to print several onlays at same time, as a single object, also being cemented at once. This protocol reduces the technique sensitivity of a vertical dimension oral rehabilitation process, reduce the chair time, enhancing the patient-comfort and delivers a unique way to restore dental lost anatomy as a definitive or temporary way with printing materials. With the advent of new CAD-CAM 3D printing materials, which are increasingly versatile and gaining favor among clinicians, it is now possible to address complex clinical situations with greater predictability. This technology enables the development of treatment solutions that are both effective and efficient, consequently reducing clinical time for the patient.

Implant Fixture Fracture Related To Angulation Path Compounded By Implant Width

Accurate implant placement is vital to the proper function and life of not only the implant fixture but also the implant-restoration structural unit. Less than 1% of implant failures occur primarily due to fracture of the implant fixture. Though the principle of implant placement today is prosthetic-driven, proper implant fixture placement is fundamental to the life of the implant-prosthesis unit and includes factors such as selection of key factors such as expertise of dentist or specialist placing the implant fixture, length, and diameter, angulation or path of insertion, length and of implant fixture. Research indicates that among the factors listed, diameter and angulation or proposed path of insertion of the implant fixture play an important role in the long-term stability of the implant fixture. In this case report, we describe a patient who underwent implant therapy, bilaterally, in the mandible. Implant fixtures were placed in the region of missing tooth #19 and #30 which were previously extracted due to pulpal disease of carious origin. In both cases, a 5.0 mm diameter implant fixture was selected to replace the missing #19 and 30. The implant placed in the #19 region was placed with the ideal angulation and subsequently restored, while the implant fixture placed in the missing #30 location was inserted at an off-angle, then subsequently restored. Three years following restoration, the patient presented with a fractured implant replacing #30. This case report emphasizes the importance of selection of appropriate implant fixture features such as diameter and angulation for the long-term survival of the entire implant-prosthesis unit. As the report would further indicate, in the region of tooth #30, it was difficult to ascertain the cause of implant therapy failure. The case report also underpins the need to pay increased attention to all factors on an individual basis that essentially compound to improve the survivability of the implant-prosthesis unit.

Rehabilitation of missing teeth with severely tilted abutment tooth using telescopic bridge: A case report

Background: Prolonged missing teeth can cause the adjacent and or antagonist teeth to migrate towards the edentulous area which then complicate the rehabilitation process. From the patient perspective, it can also affect the functional and aesthetic aspect of their life. Hence, tooth loss whether in small or big number has to be replaced. Telescopic bridge defined as an artificial crown constructed to fit over a coping. It consists of inner and outer coping where the outer coping is cemented over the inner coping. Objective: To rehabilitate posterior missing teeth with severely tilted abutment tooth by fabrication of telescopic bridge. Case Report: A 55-year-old male patient came to prosthodontics specialty clinic at Universitas Airlangga Dental hospital on his volition with a chief complaint of replacement of missing one posterior tooth on both side of lower jaw as he has difficulty in chewing food and recurrence of food entrapment on the missing teeth area. The patient reported to have had missed his lower teeth since 5 years ago. The treatment chosen for this case was telescopic bridge fabrication. This treatment was conducted in order to correct the path of insertion of the prosthesis whilst give a satisfactory aesthetic and functional result. Conclusion: Telescopic bridge can restore aesthetic and functional aspect of missing teeth with a severely tilted abutment tooth.

A Survey of Needle Steering Approaches in Minimally Invasive Surgery.

In virtue of a curved insertion path inside tissues, needle steering techniques have revealed the potential with the assistance of medical robots and images. The superiority of this technique has been preliminarily verified with several maneuvers: target realignment, obstacle circumvention, and multi-target access. However, the momentum of needle steering approaches in the past decade leads to an open question-"How to choose an applicable needle steering approach for a specific clinical application?" This survey discusses this question in terms of design choices and clinical considerations, respectively. In view of design choices, this survey proposes a hierarchical taxonomy of current needle steering approaches. Needle steering approaches of different manipulations and designs are classified to systematically review the design choices and their influences on clinical treatments. In view of clinical consideration, this survey discusses the steerability and acceptability of the current needle steering approaches. On this basis, the pros and cons of the current needle steering approaches are weighed and their suitable applications are summarized. At last, this survey concluded with an outlook of the needle steering techniques, including the potential clinical applications and future developments in mechanical design.

Retentive Behavior of Locator versus Ball Attachments on Parallel versus Non-Parallel Implants

Several factors determine the retention force in removable implant-retained overdentures using prefabricated ball- or locator-type attachment systems. In this context, it was the goal of this in vitro study to examine the effect of implant angulation and female part alignment. Two model situations with two parallel or 12° tilted implants were fabricated onto which locator or ball attachments could be mounted. Simulated prostheses (n = 5) were made as antagonist parts and the assemblies were positioned in a universal testing machine for repeatedly (three times per female attachment) quantifying retention force. Statistical analysis was based on Shapiro–Wilk tests, Levene tests, ANOVAs, Tukey’s HSD tests and Welch t-tests, with the level of significance set at p &lt; 0.05. With tilted implants, the retention force of locators was significantly diminished (p &lt; 0.004) by at least 21%, while with ball attachments, a maximum reduction of 8% was noted, with only yellow inserts showing a significant difference (p = 0.040) compared with the parallel situation. Not aligning female retentive components on tilted implants for achieving a common path of insertion in ball anchors had only a minor effect on retentive force (6.5% increase as compared with aligned female parts), which was not statistically significant (p = 0.100). Not being able to establish a common path of insertion in locator attachments affects retention force. Ball anchors allow for aligning female retentive components, but due to the spherical structure of the male component this seems not even to be necessary.

Subthalamic nucleus neuronal activity entropy in the effective stimulation area in patients with Parkinson’s disease

One of the most successful and promising treatments for Parkinson’s disease today is deep brain stimulation (DBS). Accurate localization of the stimulation area is critical for the outcome of surgical DBS electrode implantation in the subthalamic nucleus (STN). To achieve this, microelectrode recording is used during surgery to precisely locate the STN borders [1], while test stimulations with a macroelectrode are widely employed to enhance DBS electrode placement accuracy. Thus, through testing multiple trajectories, the most clinically effective one can be selected. However, a comprehensive and reliable description of the specific single neuron activity associated with successful DBS electrode implantation is currently lacking. A study was conducted using microelectrode recordings (MER) of single neuron activity in the STN of 21 Parkinson’s disease patients (UPDRS III off/on=46.9/12.8) to identify the neuronal activity features associated with the most favorable clinical outcome of test stimulation. A comparative analysis of 29 activity parameters, such as firing rate, oscillatory activity intensity in different frequency ranges (Oscores), coefficient of variation, burst, pause index, among others [2], was conducted for 618 identified neurons. In addition, the approach of computing the entropy of the change in interspike intervals (ISI) of the pulse sequence [3] and the process of identifying patterns of neural activity using hierarchical clustering [4] were implemented. A comparative analysis of single neuron activity indicated notable (p 0.05) variations between disregarded and selected paths for the ultimate implantation of DBS electrode, solely relying on entropy parameters. Trajectories that delivered optimal test stimulation outcomes demonstrated reduced entropy of interspike intervals. Only the patterns of neuronal activity characterized by extended periods of steady firing and brief pauses, referred to as tonic and pause activity, respectively, were found to contribute to the difference in entropy between trajectories. In contrast, there were no statistically significant differences detected in entropy values associated with neurons demonstrating burst activity. Furthermore, we observed a positive and significant correlation between entropy values and the degree of improvement in disease presentation before and after administration of medication. A comparative analysis was conducted on the activity of single neurons along different trajectories with varied test stimulation responses. The results showed a weak effectiveness of linear parameters in determining the optimal electrode insertion path for improved clinical outcomes. However, the use of non-linear activity parameters, specifically entropy, in single neurons effectively differentiated trajectories with significant versus absent/insignificant test stimulation results. Furthermore, the significance of entropy in establishing the basal ganglia functions and describing information transfer processes in movement control is emphasized by interpreting this parameter as a measure of uncertainty or unpredictability of the information system in relation to the findings of other studies [5].

Abstract 16973: Using an in-vitro and ex-vivo Test Platform for Evaluation of a Pen-Sized Ultrasound Vascular Access Device (Vu-Path)

Introduction: Despite several off-the-shelf ultrasound systems being used for large vessel access, reliable and safe vascular access remains a problem. This is especially true during combat casualty care where skilled operators may not be available. We tested a novel small-footprint platform for efficacy and timeliness of large vessel access at normovolemic and hypovolemic states Hypothesis: A custom-designed device with optimized ergonomics and workflow will yield high success rates and low training needs for large vessel access Methods: Vu-Path has a pen-size 10 mm ultrasound transducer with a proprietary needle guide and a lightweight engine deployed with a tablet or laptop. The display has an overlay showing the needle insertion path. Once the vessel is visible within the overlay, insertion of the needle using the needle guide directs insertion to the vessel. We used 3 models to simulate femoral vessel access: 1) a commercially available phantom (CAE Blue Phantom); 2) a custom in-vitro tissue phantom mimicking swine normovolemic and hypovolemic femoral vascular states; 3) an ex-vivo model of a euthanized swine lower-body section with canulated femoral vessels looped with a peristaltic pump to simulate normovolemic and hypovolemic states. Results: Vu-Path tested in these 3 models resulted in 87% successful insertions across all models and conditions; 100% success on the commercial model versus 83% in the custom tissue phantoms. In every model, 2 metrics were evaluated as summarized in Figure: total time to align vessel in the needle track window, and total time after aligning to confirmed insertion. Mean attempts needed to gain system expertise was 6. Conclusions: Vu-Path had high success rates for vessel visualization and needle access guidance in 3 models simulating normovolemic and hypovolemic conditions. Training requirements were minimal. These data suggest Vu-Path is capable of potentially improving safety and reliability of large vessel access.

A technique to guide implant placement with the long axis parallel to the path of insertion of removable partial dentures

A technique to guide implant placement with the long axis parallel to the path of insertion of removable partial dentures

An insertability constraint for shape optimization

Patient-specific implants offer a host of benefits over their generic counterparts. Nonetheless, the design and optimization of these components present several technical challenges, among them being the need to ensure their insertability into the host bone tissue. This presents a significant challenge due to the tight-fitting nature of the bone-implant interface. This paper presents a novel insertability metric designed to efficiently assess whether a rigid body can be inserted into a tight-fitting cavity, without interference. In contrast to existing solutions, the metric is fully differentiable and can be incorporated as a design constraint into shape optimization routines. By exploiting the tight-fitting condition, the problem of planning an interference-free insertion path is reformulated as the search for a single interference-free movement, starting from the inserted configuration. We prove that if there exists any outward movement for which no interference is indicated, then the body can be fully extracted from or, equivalently, inserted into the cavity. This formulation is extremely efficient and highly robust with respect to the complexity of the geometry. We demonstrate the effectiveness and efficiency of our method by applying it to the optimization of two-dimensional (2D) and three-dimensional (3D) designs for insertability, subject to various design requirements. We then incorporate the proposed metric into the optimization of an acetabular cup used in total hip replacement (THR) surgery where geometric and structural requirements are considered.

치간칫솔의 효율적 활용에 관한 문헌고찰

Objectives: Measures for the efficient use of interdental brush were reviewed.&#x0D; Methods: From June 1 to October 30, 2022, the significance and utilization of interdental brushes were studied, and data collection was mainly conducted using literature surveys and Internet searches.&#x0D; Results: After checking the size of the interdental brush in the mouth, education on the insertion path and use of the interdental brush should be followed. Depending on the periodontal health condition, the time of intervention of the interdental brush may vary.&#x0D; Conclusions: For efficient use of interdental brushes, it is essential to check the size of interdental brushes in the mouth, and training on the insertion path and use of interdental brushes should be followed.

The tunable effect of the second metal site on the hydroformylation of propylene over Rh-M-BTC (M= Fe, Ru, Mn, Rh, Pt, Pd, Re, Cu, Ni)

Hydroformylation is one of the most important homogeneous reactions in industry. Cu-BTC, as a kind of MOFs material with coordinate unsaturated metal sites, has strong interaction with adsorption molecules and is widely used in adsorption and catalytic research fields. The open metal sites in it can be adjusted according to the demand. In this work, Rh-BTC was selected as the catalyst for the hydroformylation of propylene. In order to regulate the electronic properties of Rh metal center, eight Rh-M-BTC materials (M= Fe, Ru, Mn, Rh, Pt, Pd, Re, Cu, Ni) were investigated. The Mulliken charge of Rh-M metal nodes and the reaction energy barrier of the key steps of propylene hydroformylation on Rh-M-BTC were calculated, including the step of propylene insertion, CO insertion, and aldehyde formation. The results showed that on Rh-Pd-BTC, the energy barrier difference between linear and branched path for the regional decisive step propylene insertion step is the lowest, only 0.04 eV. The reaction energy barrier of the linear path for CO insertion is only half of that of the branched path. The linear path has obvious advantages. Therefore, Rh-Pd-BTC was suggested as the most suitable model studied in the work for hydroformylation of propylene.

Computed tomography in measuring electrode insertion angle and depth for cricopharyngeal muscle electromyography.

Electromyography of the cricopharyngeal muscle (CP-EMG) is one of many assessment tools for dysphagia. The key to performing EMG and BTX injections is to precisely locate the cricopharyngeal muscle with an electrode. One of the main difficulties of electrode insertion is the fact that the CP muscle is located deep within the neck. Since a neck computed tomography (CT) can clearly display the CP muscle, thyroid, and blood vessels in the neck, we speculate that a safe concentric needle electrode insertion path to the cricopharyngeal muscle can be simulated with the assistance of the patient's neck CT which clearly marks the angle and depth of concentric needle electrode insertion. The purpose of this study was to explore simulated electrode insertion angles and insertion depths for cricopharyngeal electromyography based on retrospective CT data and present a method of percutaneous localization of the cricopharyngeal muscle based on CT images of the neck. One hundred and forty-three neck CT scans performed between January 2019 and November 2020 were included in this study. With the assistance of the angle and straight-line tools found in the Advantage Workstation 4.4 (GE, HealthCare), simulated insertion angles and depths from the anterior border of the sternocleidomastoid muscle to the cricopharyngeal muscle were obtained. The 143 CT images originated from participants that included 63 males (44.1%) with an average age of 46.2±13.9 years old. The insertion angle, insertion depth, and neck thickness measured on the CT images were 53.2±10.7˚, 24.2±4.1 mm, and 130.1±17.7 mm, respectively. The insertion angle and depth were significantly greater in males than in females (P<0.05), and the insertion angle increased with the age of participants (P<0.05). A generalized linear model (GLM) showed that insertion angle was positively correlated with neck thickness (β=0.14; 95% CI: 0.03 to 0.25) and gender (β=5.08; 95% CI: 1.31 to 8.85), and negatively correlated with age (β=-5.88; 95% CI: -9.54 to -1.62). Insertion depth was only positively correlated with the neck thickness (β=0.11; 95% CI: 0.07 to 0.15). This study indicates that age, gender, and neck thickness are influencing factors for insertion angle, while neck thickness is the influencing factor for insertion depth. The simulated concentric needle electrode insertion method based on CT can assist clinical operation to ensure safety and effectiveness of cricopharyngeal electromyography.

Design and evaluation of shape memory alloy-actuated active needle using finite element analysis and deflection tracking control in soft tissues.

Conventional needles lack active mechanisms for large tip deflection to bypass obstacles or guide through a desired trajectory in needle-based procedures, compromising accuracy and effectiveness. An active needle with a shape memory alloy (SMA) actuator was designed and evaluated by demonstrating deflections in tissue-mimicking gels. Finite element simulation and real-time needle tip deflection tracking in tissue-mimicking gels were performed. The active needle deflected 50 and 39mm at 150mm insertion depth in the liver and prostate mimicking gels, respectively. Reasonable simulation errors of 16.42% and 12.62% in needle deflections and small root mean squared errors of 1.42 and 1.47mm in deflection tracking were obtained. The proposed needle produced desirable large tip deflections capable of bypassing obstacles in the insertion path and tracked a preplanned trajectory with minor errors. The finite element study would help optimise needle designs and predict deflections in soft tissues.

최소침습 골절정복 수술에서 나사못 삽입 경로를 유도하는 시스템

In this paper, we propose a system to detect the location and direction of locking screw insertion using only a fluoroscopic image and guide screw insertion path, with a device that combines a SCARA robot arm and a conical remote center-of-motion (RCM) mechanism. In the proposed system, the target location and direction for screw insertion were derived from the fluoroscopic image of an intramedullary nail. The insertion guidance device comprise the SCARA robot arm and the RCM mechanism. The insertion guidance device calculated the current indicated path through forward kinematics analysis, and the target path and the current path were transmitted to the orthopedic surgeon through the control program. Moreover, the insertion guidance device set the insertion position and direction independently. The orthopedic surgeon first adjusted the SCARA robot arm to match the insertion position value to the target value and then sequentially adjusted the RCM mechanism so that the insertion direction matched the target value. After determining the insertion position and direction, the orthopedic surgeon inserted the surgical instrument through the path guided by the insertion guidance device and fastened the screw to the bone fragments and the intramedullary nail. When the proposed screw insertion guidance system was applied to fracture surgery, the locking screw was fastened with a minimum number fluoroscopic image, thus reducing surgery time and radiation exposure. The validity of the proposed method was confirmed through simulations and experiments using a fracture model.