Proper Tension Research Articles

Influencing factors on effectiveness of reverse total shoulder arthroplasty

To summarize the influencing factors on the effectiveness of reverse total shoulder arthroplasty (RTSA), so as to provide reference for clinical treatment. The related research literature of RTSA at home and abroad was extensively consulted, and the factors that may affect the effectiveness were summarized from the aspects of surgical technique, muscle condition, general condition of patients, psychological expectation, and lifestyle. For surgical techniques, different surgical approaches have their own advantages. The glenoid notch, poor bone ingrowth, increased bone resorption, and infection would lead to the loosening of glenoid prosthesis. In addition, the neck shaft angle and inclination angle of humeral prosthesis affect the occurrence of glenoid notch and the range of motion of joint internal/external rotation after operation, respectively. For muscle condition, the quality of teres minor and deltoid muscle has an important influence on joint stability after operation. Moderate increase of deltoid muscle tension can improve joint mobility after operation, and suture repair of subscapular tendon during operation can relieve joint pain and improve function, range of motion, and strength. For the general condition of patients, gender, age, and body mass index are all related to postoperative joint function and complications, and different occupations and postoperative exercise levels affect the recovery. The patients with severe degenerative diseases, poor preoperative function, and long disease duration have lower expectations and higher satisfaction with the effectiveness, and bad lifestyle has a negative impact on the effectiveness. The effectiveness of RTSA is related to surgical technique, muscle condition, general condition of patients, psychological expectation, and lifestyle. In order to avoid the loosening of glenoid prosthesis, the operator should choose humeral prosthesis with small neck shaft angle and large glenoid ball and put them down and inclined inferiorly during operation, and choose appropriate approach to eliminate space with drainage to reduce the risk of infection. After operation, patients should avoid activities that generate high anterior and posterior shear forces. In addition, the humeral prosthesis with a inclination angle of 10°-20° can achieve the best balance between the range of internal rotation and external rotation after operation. Proper deltoid tension can maintain joint stability and good range of motion. Suture of subscapular tendon is recommended.

Quantification of the passive behavior of the glenohumeral joint: A biomechanical study

Shoulder stabilization and arthroplasty procedures aim to restore the complex motion innate to the glenohumeral joint relying on proper tensioning of the surrounding soft-tissues at the time of surgery. Joint instability remains a leading cause for revisions of these procedures necessitating a deeper understanding of the passive constraint of the intact glenohumeral joint. The current literature lacks comprehensive analysis of the passive glenohumeral joint in all degrees-of-freedom (DOF). The objective of the present study is to better understand this complex joint by quantifying the passive laxity of the glenohumeral joint in multiple DOFs over a range of motion. Sixteen fresh-frozen cadaveric shoulders were tested in the intact state using a robotic simulator capable of six-DOF motion. The limits of range of motion was quantified in separate laxity tests applying a ± 2 Nm internal-external (IE) torque, ±20 N anterior-posterior (AP) force, ±20 N superior-inferior (SI) force and a 44 N distraction force at six levels of glenohumeral abduction. Overall, glenohumeral joint laxity was greatest between 15° and 45° of abduction except for SI translation which increased with abduction. IE rotation and AP translation were dominated by external rotation and anterior translation, respectively. Although early abduction and late abduction produced similar laxities, the increase in laxity in the mid abduction range indicates it is important to assess the shoulder joint throughout the range of motion and not just at these two end points. The presented laxity data establishes a baseline for intact shoulder laxity over a range of motion in multiple DOFs under known loading conditions.

Satisfactory outcomes after one-stage revision anterior cruciate ligament reconstruction using rectangular tunnel technique.

One-stage revision anterior cruciate ligament reconstruction (ACLR) with the anatomic rectangular tunnel (RT) technique using bone-patellar tendon-bone (BTB) grafts results in anatomically precise tunnel placement and secure graft fixation. This study evaluated knee joint laxity and clinical outcomes in terms of femoral tunnel overlap. It was hypothesised that there would be no significant differences in knee joint laxity or clinical outcomes regardless of femoral tunnel overlap. Between 2012 and 2021, a single surgeon conducted 196 one-stage revision ACLRs with the RT technique using BTB grafts. Patients were divided based on the presence of femoral tunnel overlap. Knee joint laxity was evaluated using the Lachman test, pivot shift test, and side-to-side difference measured with a KT-1000 arthrometer. Clinical outcomes were assessed using the Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) Knee Examination Form 2000. Knee joint laxity and clinical outcomes were compared between groups after a median follow-up of 2.5years (range 2.0-8.0). The study included 30 and 73 patients in the overlap and non-overlap groups, respectively. No significant differences were observed in the results of the Lachman test, pivot shift test, or KT-1000 arthrometer as well as in the Lysholm, KOOS, or IKDC scores between the two groups. Based on the IKDC scores, all patients were graded as normal or nearly normal. One-stage revision ACLR with the RT technique using BTB grafts improved knee joint laxity and had favourable clinical outcomes regardless of femoral tunnel overlap. To achieve optimal results in one-stage revision ACLR, it is crucial to create a tunnel within the anatomical attachment area and ensure proper graft fixation and tensioning. III.

Influence of Applied Load and Sliding Distance on Wear Performance of AlSi7Mg0.6 Aluminum Alloy

The wear performance of AlSi7Mg0.6 aluminum alloy, a casting aluminum alloy used in positioning devices for catenary systems of high-speed railways which fail frequently on lines where the speed of trains is higher than 300 m/s, is discussed in this study. It was estimated that sliding contact wear occurred and mainly contributed to the failure. To explore the competing mechanism for frictional wear failure, frictional experiments based on three groups of sliding distance (0.5 mm, 1.5 mm and 3.0 mm) and four groups of applied loads (20 N, 50 N, 100 N and 200 N) were implemented. Three-dimensional morphological observation results revealed that the wear volumes at a sliding distance of 0.5 mm were only about 1/10 of that at a sliding distance of 3.0 mm. It was also revealed that the wear volume based on a sliding distance of 3.0 mm and applied load of 20 N was still much larger than the wear volume under a sliding distance of 0.5 mm and applied load of 200 N. SEM observation of the microstructures revealed that abrasive wear was the dominant wear mechanism in dry sliding friction conditions. A simplified positioning device model was also established to study the influence of tension force on wear performance. The simulation results revealed that smaller tension force between the positioning support and positioning hook would lead to higher relative sliding distance and larger wear depth. Sliding contact friction should be avoided due to relatively large wear efficiency compared with rolling contact friction. Both experimental and simulation results suggested that proper tension force was preferred in assembling components which could ensure rolling contact friction rather than sliding contact friction.

DETECTING ANOMALIES IN STRUCTURAL RESPONSE OF CABLE SUPPORTED BRIDGES: AFTER EXTREME EVENTS

AbstractThe safety of cable‐supported bridges primarily depends on cable design, proper tensioning during construction, and regular maintenance. Over the past decade, numerous cable‐supported bridges have faced various issues, including aging, poor tensioning practices, coping with heavy traffic loads, insufficient maintenance, and exposure to accidents or extreme conditions. Despite these challenges, these structures often withstand such problems due to the inclusion of redundancy and alternative load paths in their design. Detecting anomalies in bridge monitoring data can aid in identifying potential issues. Typically, only specific cables are monitored in a cable‐supported bridge monitoring system. The conditions of non‐monitored cables are usually estimated based on the data from adjacent cable sensors. The structural response of the tower and the deck can also be indirectly estimated. This research aims to present a methodology for detecting anomalies in structural responses following extreme events. It is crucial to differentiate temporary changes in cable measurements caused by expected seasonal temperature fluctuations, regular winds, and normal traffic patterns from permanent changes resulting from extreme events. Additionally, one must consider that a permanent change in measurements might also occur due to sensor loss after an extreme event. The paper will discuss tools to form a detection that can identify whether the source of change is due to a real extreme event or not.

Optimizing Yarn Tension in Textile Production with Tension–Position Cascade Control Method Using Kalman Filter

The production of textiles has undergone a considerable transformation, progressing from its primitive origins in hand-weaving to the implementation of contemporary automated systems. Weaving yarn into fabric is a crucial process in the textile industry that requires meticulous attention to output quality products, particularly in the tension control section. The efficiency of the tension controller in relation to the yarn tension significantly affects the quality of the resulting fabric, as proper tension control leads to strong, uniform, and aesthetically pleasing fabric, while poor tension control can cause defects and yarn breakage, leading to production downtime and increased costs. Maintaining the desired yarn tension during textile production is crucial, although it poses several problems, such as the continuous diameter change of the unwinder and rewinder sections leading to system change. Another problem faced by the industrial operation is maintaining proper tension on the yarn while changing the roll-to-roll operation velocity. In this paper, an optimized method for controlling yarn tension through the cascade control of tension and position, incorporating feedback controllers, feedforward, and disturbance observers, has been proposed to make the system more robust and suitable for industrial use. In addition, an optimum signal processor has been designed to obtain sensor data with reduced noise and minimal phase difference.

Three-dimensional high aspect ratio interface elements for simulating 3D hydraulic fracturing in deformable porous media

Hydraulic fracturing (HF) is a technique widely used in the oil industry to stimulate low permeability reservoirs and enable their production. However, to model the HF is necessary to consider at least three main coupling process: (i) the fluid pressure deforming the fracture walls, (ii) the fluid flow inside the fracture, and (iii) the fracture propagation through the porous medium. In this context, this work aims to expand the applicability of the high aspect ratio interface elements (HAR-IE) to simulate the formation and propagation of induced hydraulic fracture in three-dimensional scenarios. The proposed methodology considers a deformable porous media in which the fluid flow is governed via Darcy’s law. A proper tension continuum damage model is employed to deal with the fracture formation process and the classical cubic law defines the fluid flow in the fracture. A fully-coupled method solves the system of equations and the numerical results focus on the validation of the method via comparisons against analytical solutions. All the results showed that 3D HAR-IEs satisfactorily reproduce the main characteristics associated with HF, as fracture aperture, length and injection pressure.

SPECIAL ISSUE: A Student's Story of Self-Directed Work with Biofeedback for Optimal Performance

For musicians, performance problems often go unnoticed and ignored. Many arise from overpractice and incorrect body alignment, especially in the arm, hand, and fingers. Problems manifest physiologically as muscle tension, bracing or constriction, and anxiety. Retraining with surface electromyography biofeedback and video helps identify elevations in muscle tension and incorrect body alignment. Work with biofeedback for stress reduction and neuromuscular reeducation in retraining increases self-awareness and provides feedback on practice of techniques to achieve proper tension and release of muscles, manage stress, and achieve optimal performance.

Modeling of tow tension fluctuations and parameter optimization during the stable transfer phase for automated fiber placement

The fluctuation in tow tension is critical for Automated Fiber Placement (AFP). However, it has not been widely studied. In this paper, a tension variation equation was developed to represent the tension fluctuation during AFP, and experiments were used to demonstrate the validity of the equation. According to the equation, the degree of bending rigidity, power-law friction, and extensibility influence on the tension change was obtained. Additionally, the effects of bending rigidity and extensibility can be disregarded during AFP. Moreover, automatic wire feeding and laying trials were carried out separately, and proper tensions (T = 3 N) for wire feeding and layup under experimental conditions were obtained. Therefore, the equation provides theoretical support for the structural and parameter optimization of the AFP.

A Novel Technique of Arthroscopic Femoral Tunnel Placement during Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocation.

Recurrent patellar dislocation is a commonly encountered patellofemoral disease. Prompt surgical intervention is indicated for recurrent dislocation to restore patellofemoral stability. As one of the most preferred procedures, medial patellofemoral ligament (MPFL) reconstruction has been implemented on a large scale. Femoral tunnel placement remains a crucial technical issue during MPFL reconstruction and is critical to ensure the isometry and proper tension of the graft. Currently, visual-palpatory anatomic landmarks and fluoroscopy-guided radiographic landmarks comprise the main approaches to intraoperative femoral tunnel positioning. However, the accuracy of both methods has been questioned. This article introduces an arthroscopic femoral tunnel placement technique. Apart from traditional anteromedial and anterolateral portals, two auxiliary arthroscopic portals are specially designed. The adductor tubercle, the medial epicondyle and the posterior edge are selected as main anatomic landmarks and are directly visualized in sequence under arthroscope. The relative position between the femoral attachment of the MPFL and the three landmarks is measured on preoperative three-dimensional computed tomography, providing semi-quantified reference for intraoperative localization. This technique achieves minimally invasive tunnel placement without X-ray exposure, and especially suits obese patients for whom palpatory methods are difficult to perform.

Medial patellofemoral ligament reconstruction using a digital tensiometer to determine graft tension: Surgical technique and mid-term follow-up.

The optimal method for achieving proper graft tension during patellofemoral ligament reconstruction is a topic of debate. In the past, a digital tensiometer was used to simulate the knee structure, and a tension of approximately 2N was identified as suitable for restoring the patellofemoral track. However, it is unclear whether this tension level is sufficient during the actual surgery. The objective of this study was to verify the efficacy of graft tension using a digital tensiometer for medial patellofemoral ligament (MPFL) reconstruction and to conduct a mid-term follow-up. The study enrolled 39 patients who had experienced recurrent patellar dislocation. Preoperative computed tomography scans and X-rays confirmed patellar instability, patellar tilt angle patellar congruence angle and the history of dislocation and patellar apprehension test. Knee function was evaluated using preoperative and postoperative Lysholm and Kujala scores. The study included 39 knees, comprising 22 females and 17 males, with an average age of 21.10 ± 7.26. The patients were followed up for at least 24months through telephone or face-to-face questionnaires. All patients had a preoperative history of ≥2 patellar dislocations, none of which were surgically treated. During surgery, all patients underwent isolated MPFL reconstruction and lateral retinacula release. The mean Kujala and Lysholm scores were 91.28 ± 4.90 and 90.67 ± 5.15, respectively. The mean PTA and PCA were 11.5 ± 2.63 and 2.38 ± 3.58, respectively. The study found that a tension of approximately 27.39 ± 5.57N (14.3-33.5N) was required to restore the patellofemoral track in patients with recurrent patellar dislocation. No patients required reoperation during the follow-up period. Overall, 36 out of 39 patients (92.31%) reported no pain when completing daily activities at the last follow-up. In conclusion, a tension level of approximately 27.39 ± 5.57N is necessary to restore normal patellofemoral relationships during clinical practice, which indicates that using a tension of 2N is too low. The use of a tensiometer during patellofemoral ligament reconstruction is a more accurate and reliable surgical procedure for treating recurrent patellar dislocation.

Clinico-radiological correlation of reverse shoulder arthroplasty outcomes

<p>Positioning of prosthetic components is essential for the success and longevity of the prosthesis. Judging prosthetic implantation radiologically is always beneficial; plain radiographs and computed tomography can provide information regards inclination and version of glenoid component, besides, lateralization of prosthetic components.<strong> </strong>This study aims at postoperative radiological evaluation of component positioning of reverse shoulder prosthesis and correlating measured radiological parameters with clinical outcome.<strong> </strong>Radiological assessment was carried on by radiographs taking advantage of true anteroposterior projection, and midaxial two-dimensional computed tomography cut. Radiographs evaluated glenoid inclination in coronal plane (superior-inferior tilt) via global inclination angle, and critical shoulder angle. Center of rotation was evaluated by calculating acromion index. Additionally, acromiohumeral interval, and deltoid lever arm distance were documented. Midaxial CT cuts evaluated glenoid version. Each parameter was correlated to postoperative clinical outcome represented in range of motion and total functional scores.<strong> </strong>the mean acromion index revealed significant change to 63.82±9.06%, total medialization surged significantly with average 1.51 cm with a mean postoperative calibrated center of rotation-distance of 3.72±0.78 cm. The mean increase in acro-mio-humeral interval was 1.57 cm with a new postoperative value of 2.49±0.9 cm. The mean glenoid version declined to 5.7º±5º, however, this change was not significant.<strong> </strong>In conclusion, accurate positioning of shoulder prosthesis components with proper tensioning of soft tissue envelope within acceptable measurement parameters is considered crucial for stability and longevity of implant with the best clinical outcomes.<strong></strong></p>

Extended deltopectoral approach for revision total elbow arthroplasty requiring humeral allograft-prosthetic composites in patients with severely compromised proximal humerus bone stock

Severe humeral bone loss in the setting of failed total elbow arthroplasty (TEA) poses a particularly challenging reconstructive problem. The objective of this study was to review the rationale, indications, contraindications, and detailed surgical technique for using an extended anterior deltopectoral approach to perform a revision TEA when substantially long allografts are required in the presence of severely compromised proximal humerus bone stock. The authors developed this exposure and reconstructive strategy for failed elbow arthroplasties where the remaining segment of proximal humerus is extremely short, which makes adequate plate fixation of an allograft-prosthetic composite (APC) to the native bone extremely challenging. From an anterior deltopectoral approach, it is possible to use dedicated long, precontoured proximal humerus locking plates to maximize fixation in any remaining proximal humerus. This exposure still makes it possible to provide adequate access to the coupling mechanism of the humeral and ulnar components for implantation of a linked elbow arthroplasty. This exposure also allows for adequate judgment of humeral length and rotation. Crucial steps in the surgery include extending the dissection past the elbow flexion crease such that one can obtain circumferential exposure of the distal humerus. It is also important to couple the humeral and ulnar components prior to committing to the length of the APC. Special attention must be paid to gauge appropriate APC rotation and length for proper soft tissue tension. When performing fixation of the proximal humeral plate, screw purchase must be maximized in both the remaining native proximal humerus and the APC. Compression across the allograft-host interface is paramount for healing to occur. An extended anterior deltopectoral approach to perform a revision TEA when very long APCs are required is a viable option to restore humeral bone stock and regain humeral stem fixation in the setting of failed TEA with extensive humeral bone loss.

Trans-Obturator Tension Appliance Tape for failed Mid-Urethral Sling when and how?

Background & Objectives: Female urinary incontinence is a significant health issue affecting adult women, most suffering from stress incontinence. It affects the quality of life. Recurrence after surgery is difficult for the patients and the surgeon. There is no precise data to show how to treat failed Transobturator tape. Transobturator tape with tension may be an alternative method in applying proper tension in the mid urethra to correct the incontinence. We describe our experience to evaluated outcomes of the second mid-urethral sling with tension to treat recurrent incontinence after the failure of the first mid-urethral sling. Methods: A prospective cohort study was conducted between Oct. 2012 to March 2019. A total of 16 patients with failed Transobturator tape surgery underwent second trans-obturator Mid-Urethral Sling surgery. Preoperative data and postoperative complications were recorded. All patients were followed for one year. Results: Sixteen women after failed Mid-Urethral Sling surgery were evaluated. At a mean follow-up of 7.5 months, the cure rate was 62.5% (10 out of 16) patients. Partial cure (improvement) was achieved in 25% ( 4 patients out of 16) and failure in 2 patients, 12.5%. There were statistically significant improvements after surgery in the Q-tip test and the number of the pads. Conclusion: Repeat Transobturator tape with tension treatment tends to result in good outcomes with a reasonable physician-determined success rate.

The Effect of an Additional Core Suture During Pulvertaft Tendon Repair: A Fresh-Frozen Cadaver Study

Pulvertaft tendon repair is a strong suture technique; however, proper tendon tension is impaired by repair site elongation. Therefore, methods to reduce postoperative elongation are warranted. This study aimed to determine the effects of additional core sutures during Pulvertaft tendon repair on repair site elongation and rupture strength. A total of 48 finger extensor tendons were harvested from fresh-frozen cadavers, and tendons with similar diameters were paired. The 24 pairs of tendons were divided into the following 4 groups: group I, 3 interlaced weaves only; group II, 3 interlaced weaves and 2 core suture strands with 4-0 nylon; group III, 3 interlaced weaves and 2 core suture strands with 4-0 FiberWire; and group IV, 4 interlaced weaves only. Each sutured tendon was placed in a Universal Testing Machine, and repair site elongation after repeated traction loads and rupture strength were measured. The mean elongation values were 2.74 ± 0.84 mm, 1.80 ± 0.16 mm, 1.60 ± 0.18 mm, and 1.92 ± 0.18 mm for groups I, II, III, and IV, respectively. The elongation values were significantly lower in groups II, III, and IV than in group I. The mean rupture strengths were 64.9 ± 16.0 N, 94.8 ± 17.2 N, 110.9 ± 21.3 N, and 104.9 ± 17.5 N for groups I, II, III, and IV, respectively. Rupture strengths were significantly higher for groups III and IV than for group I. After adding core sutures during Pulvertaft tendon repair, the elongation amount decreased, and the rupture strength improved. The study showed the effect of additional core sutures during Pulvertaft tendon repair, suggesting that it could be useful in reducing postoperative tendon elongation when extensor tendon transfers are performed.

Modeling and Adaptive Tension Control of Chain Transmission System With Variable Stiffness and Random Load

In the fully mechanized mining face, proper chain tension of chain transmission system is of great significance in reducing the failure rate and improving the service life of scraper conveyor. However, the disturbance caused by random load and variable stiffness makes it very difficult to control chain tension. An adaptive tension control scheme combining a neural command filtering backstepping algorithm and online identification is proposed in this article based on a novel tension model. First of all, the proposed tension model is represented by a linear regression part and a nonlinear mapping part, which effectively reflects the chain transmission characteristics and avoids the full measurement of each chain ring. Then, Levant's differentiator and state observer are used to expand input variables for identification algorithm and neural networks estimation. To avoid the adverse effect of random load on parameter adaption, stiffness online identification algorithm is employed in improving the tension tracking performance. To compensate for nonlinear mapping part and uncertain nonlinearity caused by random load, neural adaptive estimator is effectively integrated with the robust integral term in backstepping design. Moreover, Lyapunov stability of the proposed controller is guaranteed. Finally, comparative experimental results of six controllers are completed to verify the effectiveness of the proposed controller in the static and random load mode.

Molecular Mechanisms of Changes in Homeostasis of the Dermal Extracellular Matrix: Both Involutional and Mediated by Ultraviolet Radiation.

Skin aging is a multi-factorial process that affects nearly every aspect of skin biology and function. With age, an impairment of structures, quality characteristics, and functions of the dermal extracellular matrix (ECM) occurs in the skin, which leads to disrupted functioning of dermal fibroblasts (DFs), the main cells supporting morphofunctional organization of the skin. The DF functioning directly depends on the state of the surrounding collagen matrix (CM). The intact collagen matrix ensures proper adhesion and mechanical tension in DFs, which allows these cells to maintain collagen homeostasis while ECM correctly regulates cellular processes. When the integrity of CM is destroyed, mechanotransduction is disrupted, which is accompanied by impairment of DF functioning and destruction of collagen homeostasis, thereby contributing to the progression of aging processes in skin tissues. This article considers in detail the processes of skin aging and associated changes in the skin layers, as well as the mechanisms of these processes at the molecular level.

Impact of oxygen-calcium-generating and bone morphogenetic protein-2 nanoparticles on survival and differentiation of bone marrow-derived mesenchymal stem cells in the 3D bio-printed scaffold

Although stem cell therapy is a major area of interest in tissue engineering, providing proper oxygen tension, good viability, and cell differentiation remain challenges in tissue-engineered scaffolds. In this study, an osteogenic scaffold was fabricated using the 3D bio-printing technique. The bio-ink contained alginate hydrogel, encapsulated human bone marrow-derived mesenchymal stem cells (hBM-MSCs), calcium peroxide nanoparticles (CPO NPs) as an oxygen generating biomaterial, and bone morphogenic protein-2 nanoparticles (BMP2 NPs) as an osteoinductive growth factor. CPO NPs were synthesized with the hydrolysis–precipitation method, and their concentrations in the bio-ink were optimized. Scaffolds containing CPO 3% (w/w) were preferred, because they generated sufficient oxygen gas for 20 days, increased mechanical strength after 20 days, and had sufficient stability. The CPO NPs effect on the viability of embedded hBM-MSCs under hypoxic conditions was analyzed. Live/Dead staining results represented a 22% improvement in CPO 3% scaffold viability on day 7. Therefore, CPO NPs constituted a promising survival factor. BMP2 NPs were prepared with the double emulsification technique. The incorporation of both BMP2 and CPO NPs resulted in the upregulation of Runt-related transcription factor 2, Collagen type I alpha 1, and the osteocalcin genes compared to internal references in osteogenic media. Overall, the proposed 3D bio-printed osteogenic scaffold in this study has moved scientific research one step forward toward successful stem cell therapy and helped improve host tissue healing by biological activity enhancement, especially for low oxygen pressure tissues.

A novel flexible auxiliary single-arm transluminal endoscopic robot facilitates endoscopic submucosal dissection of gastric lesions (with video).

Using conventional endoscope to perform endoscopic submucosal dissection (ESD) is difficult because of the one-handed operation and blind dissection caused by gravity. Poor visualization of the submucosal plane causes ESD to be associated with a high risk of bleeding and perforation. This study aimed to develop a novel ESD-assistive robot system and to evaluate its efficacy. A novel flexible auxiliary single-arm transluminal endoscopic robot (FASTER) was developed. A total of 36 artificial lesions in ex vivo porcine stomachs were removed using the FASTER-assisted ESD method (n = 18) and the conventional ESD method (n = 18). Lesions were 2cm or 4cm in diameter, located on the anterior and posterior walls of the antrum. Primary outcome measurements were dissection time and dissection speed. The dissection time in FASTER-assisted ESD was significantly shorter than that in conventional ESD (7min vs 13min, p = 0.012), mainly because of the faster dissection speed (148.6 vs 97.0 mm2/min, p = 0.002). The total procedure time in FASTER-assisted ESD was shorter than that in conventional ESD, but the difference was not significant (16min vs 24min, p = 0.252). Complete en bloc resection was achieved in all lesions. No perforations were detected. The FASTER exhibited the ability of regrasp, multidirectional traction, and proper tension control during ESD. FASTER significantly increased the dissection speed by providing proper traction and achieving good submucosal vision. This new device is expected to facilitate ESD in clinical practice.

Validation of a novel virtual reality simulation system with the focus on training for surgical dissection during laparoscopic sigmoid colectomy

BackgroundMastery of technical skills is one of the fundamental goals of surgical training for novices. Meanwhile, performing laparoscopic procedures requires exceptional surgical skills compared to open surgery. However, it is often difficult for trainees to learn through observation and practice only. Virtual reality (VR)-based surgical simulation is expanding and rapidly advancing. A major obstacle for laparoscopic trainees is the difficulty of well-performed dissection. Therefore, we developed a new VR simulation system, Lap-PASS LP-100, which focuses on training to create proper tension on the tissue in laparoscopic sigmoid colectomy dissection. This study aimed to validate this new VR simulation system.MethodsA total of 50 participants were asked to perform medial dissection of the meso-sigmoid colon on the VR simulator. Forty-four surgeons and six non-medical professionals working in the National Cancer Center Hospital East, Japan, were enrolled in this study. The surgeons were: laparoscopic surgery experts with > 100 laparoscopic surgeries (LS), 21 were novices with experience < 100 LS, and five without previous experience in LS. The participants’ surgical performance was evaluated by three blinded raters using Global Operative Assessment of Laparoscopic Skills (GOALS).ResultsThere were significant differences (P-values < 0.044) in all GOALS items between the non-medical professionals and surgeons. The experts were significantly superior to the novices in one item of GOALS: efficiency ([4(4–5) vs. 4(3–4)], with a 95% confidence interval, p = 0.042). However, both bimanual dexterity and total score in the experts were not statistically different but tended to be higher than in the novices.ConclusionsOur study demonstrated a full validation of our new system. This could detect the surgeons' ability to perform surgical dissection and suggest that this VR simulator could be an effective training tool. This surgical VR simulator might have tremendous potential to enhance training for surgeons.