Ergonomic Handle Research Articles

A novel injection device to administer repository corticotropin injection for inflammatory disease treatment: findings from a market research study.

Aim: The goal of this market research study was to determine the usability of a single-dose prefilled injector (SelfJect™) for administration of Acthar® Gel (manufactured by Mallinckrodt Pharmaceuticals, UK) in patients with inflammatory diseases by obtaining feedback from patient and practitioner user groups in the US. Materials & methods: Patients and healthcare professionals (HCPs) representing relevant therapeutic areas were enrolled in the study between February and March 2021. SelfJect was mailed to patients and HCPs prior to 90-minvirtual video-recorded focus group sessions and 60-min1:1 virtual interviews, respectively. Patients completed an online assignment prior to the group session, which included instructions on how to use SelfJect and questions about their initial reaction while handling the device. HCPs were instructed to not open the package until the interview. Feedback from patients and HCPs were captured by open-ended questions and ranking scales. Results: Twelve patients and 42 HCPs participated in the study. Most patients (9/12 [75%]) and HCPs (38/42 [90%]) had experience with injectable medications, and 7/12 (58%) and 30/42 [71%] had experience with Acthar injections, respectively. Most patients and HCPs reported that key benefits of SelfJect were accurate dose delivery and ease of use, including the ergonomic handle and elimination of drawing Acthar from a vial into a syringe. Patients expressed some concerns about storage and disposal, but the need to store SelfJect would not deter them from using it. Most patients (9/12 [75%]) felt prepared to inject Acthar after reviewing the instructions. HCPs anticipated that 75% to 100% of patients would benefit switching from the vial to SelfJect. Conclusion: All participants expressed positive perceptions for SelfJect including easy use, few preparation steps and potential reduced anxiety due to needle phobia. These attributes may help treatment adherence for patients and caregivers.

Effect of a Novel Ergonomic Sheath on Dental Device-Related Muscle Work, Fatigue and Comfort-A Pilot Clinical Study.

Background: Dental instrumentation with hand-held devices is associated with discomfort, fatigue and musculoskeletal diseases or repetitive stress injuries. The goal of this in vivo study was to determine the effect of an ergonomic handle sheath on muscle work, comfort and fatigue associated with (a) piezoelectric scaling by hygienists with and without musculoskeletal disorders (MSDs), and (b) dental cavity preparation by healthy dentists using a dental micromotor. Materials and Methods: Two groups of ten hygienists each tested the piezoelectric scaler. Hygienists in Group 1 had no MSDs, while those in Group 2 had been diagnosed with MSDs. Additionally, ten dentists with no MSDs used a dental micromotor to prepare four standardized cavities. Time-based work in four muscles, comfort and fatigue were recorded in the presence and absence of an add-on soft, insulating handle sheath. Data were analyzed using a repeated measures analysis of variance model with Tukey's post-hoc test. Results: Comfort, fatigue and muscle work were significantly better for both devices when the sheath was used. While hygienists with MSDs used more muscle work to complete the set scaling task, and the sheath-related reduction in work was somewhat greater, these MSD-related differences did not quite reach significance. Conclusions: The results of this pilot study show that the ergonomic performance of an ultrasonic scaler and a dental micromotor may be improved by the use of an ergonomic handle sheath.

An Ergonomic Flexible Multi-Fire Clip Applier With Multiple Degrees-of-Freedom for Minimally Invasive Surgery to Improve Hemostatic Efficiency

Abstract Hemorrhage can lead to shock and even death of patients, making one of the main risks in surgical procedures. Most traditional clip appliers are rigid, have limited flexibility, and can only fire a single clip within each insertion, which cannot meet the needs of surgeons to efficiently and flexibly control bleeding vessels. In this study, a novel hand-held Hem-o-lok clip applier is proposed, which is designed to have a high flexibility and allow multiple fires of clips. The wrist at the end effector consists of discrete joints and a flexible shaft, allowing bending in two directions. The tong head at the end effector enables multiple fires of hemostats and can be delivered to different positions for clamping blood vessels and human tissues. It also can be driven to rotate by the flexible shaft. Additionally, an ergonomic handle is designed to control the multiple degrees-of-freedom (DOFs) movements of the instrument tip. Finally, the effectiveness of the entire system is evaluated through performance experiments. The bending angle of end effector was about ±70 deg in both directions (yaw and pitch), and the rotation angle was ±160 deg. The measured gripping forces of the applier ranged from 16.70 N to 24.93 N, and the average time to complete three consecutive clamping was 8.67 s. The proposed clip applier could improve the hemostatic efficiency and allow an intuitive and flexible operation in the meantime.

Deformation of palmar hand measurements in a power grip by wrist ulnar/radial deviation

ObjectivesThe present study analyzed changes in palmar hand measurements during power grip by wrist radial/ulnar deviation for an ergonomic grip design. MethodTwelve palmar dimensions (Tip-to-PTC/DTC distances, Tip-to-MMC distances, and Tip-to-MMC surface lengths) of digits 2 to 5 were measured for 30 Koreans with various hand sizes (15 males and 15 females; hand length = 177.9 ± 12.3 mm) at three wrist postures (neutral, 20° of radial deviation, and 30° of ulnar deviation) using 3D scanning and casting methods. ResultsAs the hand changed from the straight neutral posture to the power grip posture, the Tip-to-PTC/DTC distances (related to grip widths), Tip-to-MMC distances (related to grip heights), and Tip-to-MMC surface lengths (related to grip circumferences) decreased to 30%–65% compared to corresponding original lengths. Wrist posture also had significant effects on the Tip-to-PTC/DTC and Tip-to-MMC distances by 6.5%–9.0%, while finger position significantly affected all the measurements by 8.2%–22.3%. Practitioner summaryThe measurement protocol of palmar hand dimensions and the changes in palmar hand measurements by wrist posture are of use to develop an ergonomic handle design for comfort and prevention of musculoskeletal disorders.

Safety and Effectiveness of a Novel Tips Access Set with Steerable Cannula in a Swine Model

PurposeThis study aimed to assess the safety, effectiveness, and feasibility of the Liverty™ transjugular intrahepatic portosystemic shunt (TIPS) access set, which has an ergonomic handle that allows for in situ cannula tip deflection and a distal steerable cannula angle, versus the COOK® Rosch-Uchida Transjugular Liver Access Set (RUPS-100) in healthy pigs.MethodsTwelve pigs randomly underwent TIPS with the Liverty™ set or the RUPS-100 set. Three interventionalists performed 4 TIPS procedures, 2 with each set. The primary outcome was procedural success, defined as successful establishment of the intrahepatic portosystemic shunt and stent placement.ResultsThe shunt was successfully established in 11 pigs. The procedural success was achieved in all 6 pigs in the Liverty™ group and 5 out of 6 pigs for the RUPS-100 group (Fisher exact test, P > 0.999). The mean duration of puncture was shorter in the Liverty™ group versus the RUPS-100 group (12.3 ± 4.5 min vs. 16.2 ± 8.5 min), but without significant statistical difference (two sample t test, P = 0.359). The cannula angle was adjusted 69% of passes in the Liverty™ group, which was significantly higher than that in the RUPS-100 group (12%, P = 0.004). Overall, the TIPS procedural performance was comparable between the groups. Both sets were safe. No intraabdominal hemorrhage, vascular injuries, tissue or organ injuries, porto-biliary fistula, biliary peritonitis, and infection or abscess occurred in either group.ConclusionThe Liverty™ set is safe and has similar procedural metrics to the COOK® RUPS-100 set. It allows in situ adjustment of the angle of the stiffening cannula without increasing procedure time and lessens the occurrences of periprocedural complications.Graphical

Characterizing the effects of an ergonomic handle on upper limbs kinematics and neuromuscular activity, comfort, and performance during ergometer rowing

Articular stress and discomfort during repetitive movements may impact the risk of injuries of the upper limbs during ergometer rowing, especially when using a regular circular handle. Therefore, the purpose of the study was to propose and evaluate the influence of an ergonomic handle on upper limbs biomechanics, comfort and performance during ergometer rowing. An ergonomic irregular hexagon handle, with a 1:1.25 width/length diameters ratio, has been developed. Left upper limb kinematics and neuromuscular activity, perceived comfort and power production were monitored for 29 expert rowers. The ergonomic handle increased the perceived comfort while maintaining the overall articular stress and performance as the same level compared to the regular handle. We recommend using irregular hexagon handles with 1:1.25 ratio for ergometer rowing. Further improvements of the ergonomic handle such as an individualization based on the user's hand length may further enhance comfort and achieve better performance.

Load analysis of hands and feet while using different types of crutches with various leg's weight bearing.

The study aimed to define the load on hands using various commonly used types of crutches while walking with a full load on both legs (FL), with 20 kg partial load (PL), or with the left leg wholly unloaded (UL). Twenty-six healthy subjects used crutches with ergonomic handles, with anatomic handles (wider and softer bearing surface), and arthritis crutches (horizontal supporting area for the forearm). Sensor mats between hand and handles continuously measured the load transmitted, while sensor soles in the shoes recorded the ground reaction forces simultaneously. The load on the palm and separately the radial and ulnar halves of the palm were analyzed. With arthritis crutches, significantly lower load was transferred to the hands compared to forearm crutches (FL 3% vs. 25% of body weight, PL 8% vs. 87%, UL 12% vs. 103%). The load on hands increased significantly from FL to PL and UL for both types of crutches. The ipsilateral left hand had to bear significantly more load than the right hand. However, the feet's time-ground reaction curves showed more irregularities, and PLon the left leg was significantly higher with arthritis crutches. Anatomic handles reduced the load on the ulnar half of the palm (FL 3% vs. 5%, PL 13% vs. 18%, UL 17% vs. 23%); the radial half of the palm had a similar load to bear with both types of handles (11/11%, 31/32%, 34/35%). Arthritis crutches allow unburdening hands at the expense of gait stability. Anatomic handles reduce the load on the Guyon's canal.

Helping Surgeons’ Hands: A Biomechanical Evaluation of Ergonomic Instruments

"Ergonomic" is a common descriptor for a desk or computer workspace but is a term rarely used to describe a surgical instrument. Instead, surgeons spend many hours in inconvenient positions, often using instruments that are not ergonomic. Improving the ergonomics of surgical instruments may decrease the required force for simple tasks and allow for more efficient surgery. To evaluate the impact of ergonomic surgical instruments, the authors developed ergonomic screwdriver handles. The shape and size of these handles were engineered using previous dental studies and 3-dimensional modeling to create an ideal handle for specific glove sizes. Participants were recruited to test 3 different ergonomic handle sizes against a standard screwdriver while assessing digital peak force, digital contact area, and participant preference. Ten participants (3 women) with glove sizes ranging from 6 to 8 were evaluated. Ergonomic screwdriver handles sized for glove sizes 6 and 7 required significantly less thumb peak force than the standard screwdriver for all participants (702 N for glove size 6 and 567 N for glove size 7 ergonomic screwdrivers, vs 1780 N for "one size fits all" standard screwdriver). Participants consistently preferred screwdrivers that required lower thumb and index finger forces. All ergonomic handles required lower thumb and index finger force. Eighty percent of participants preferred a screwdriver modeled within 1 glove size of their own. Improved ergonomic handles require less force and are preferred by surgeons. The significant decrease in thumb peak force for glove sizes 6 and 7 suggests that there is room for ergonomic improvement in instruments, especially for surgeons with smaller hands. Manufacturing ergonomic screwdriver handles and using the evolving convenience of 3-dimensional printing may help to develop a more comfortable work environment for surgeons.

Analysis of the main occupational risks in community sugar mills of the Corregimiento de San Bernardo Municipality of Ibagué

According to FEDEPANELA, the national panela agroindustry generates livelihoods for around 350,000 family groups in the country. According to the Ministry of Agriculture and Rural Development, the cultivation of sugarcane for the production of panela in 2018 is 1,612,282 tons, cultivated on 367,251 hectares nationwide. In general, the largest production of panela is carried out on small farms through artisanal processes in which a high intensity of family work prevails and very low rates of technology introduction.
 From Occupational Health and Safety as a science, significant effects can be found in terms of occupational risks in the activity, the objective of the project is to analyze the main ergonomic impacts in the sugar mills. Previous studies have already concluded about the serious repercussions for the worker due to musculoskeletal injuries and the possible development of occupational diseases derived from poor ergonomic handling.
 
 The study will be carried out in a sugar mill located on the outskirts of the municipality of Ibagué and will allow characterizing the biomechanical risk factors related to Strength and Biomechanics, Load Management, Postural Loads and repetitiveness in the tasks of said productive units; The diagnosis resulting from the research can help improve the way tasks are carried out, design more suitable jobs, propose the development of ergonomic devices, improve productivity, optimize times and help a rural population dedicated to this work. much healthier..

The digital twin model of vehicle containers to provide an ergonomic handling mechanism

Late order loss for difficulty handling (loading and unloading) activities left an alarm message to make traditional transportation handling for distribution e-commerce more accessible through mitigating it to semi-auto actions. This article discusses the idea of Vehicle Containers made up of Permutational Drawers, i.e., VCPD, that ensure ergonomic handling. The proposed Ergonomic Digital Twin (EDT) manages the VCPD by the Internet of things, i.e., IoT. The VCPD object has two dimensions: drawers' size and motion mechanism. These targets are implemented via establishing the digital twins' model, i.e., DT, for these drawers to test its qualifying for implementation, mainly if supported by IoT. There is still much confusion regarding the DT and how it will apply to the VCPD in medium-sized schemes for transportation enterprises. This work activates the IoT to bolster and simplify transportation activities through designing VCPD and control via a unified framework having several standard steps to reduce execution time, effort, and transportation costs.

Robotic Handle Prototypes for Endoscopic Endonasal Skull Base Surgery: Pre-clinical Randomised Controlled Trial of Performance and Ergonomics

Endoscopic endonasal skull base surgery is a promising alternative to transcranial approaches. However, standard instruments lack articulation, and thus, could benefit from robotic technologies. The aim of this study was to develop an ergonomic handle for a handheld robotic instrument intended to enhance this procedure. Two different prototypes were developed based on ergonomic guidelines within the literature. The first is a forearm-mounted handle that maps the surgeon’s wrist degrees-of-freedom to that of the robotic end-effector; the second is a joystick-and-trigger handle with a rotating body that places the joystick to the position most comfortable for the surgeon. These handles were incorporated into a custom-designed surgical virtual simulator and were assessed for their performance and ergonomics when compared with a standard neurosurgical grasper. The virtual task was performed by nine novices with all three devices as part of a randomised crossover user-study. Their performance and ergonomics were evaluated both subjectively by themselves and objectively by a validated observational checklist. Both handles outperformed the standard instrument with the rotating joystick-body handle offering the most substantial improvement in terms of balance between performance and ergonomics. Thus, it is deemed the more suitable device to drive instrumentation for endoscopic endonasal skull base surgery.

A Surgical Kit for Stem Cell-Derived Retinal Pigment Epithelium Transplants: Collection, Transportation, and Subretinal Delivery.

Transplantation of stem cell-derived retinal pigment epithelium (RPE) cells is a promising potential therapy for currently incurable retinal degenerative diseases like advanced dry age-related macular degeneration. In this study, we designed a set of clinically applicable devices for subretinal implantation of RPE grafts, towards the overarching goal of establishing enabling technologies for cell-based therapeutic approaches to regenerate RPE cells. This RPE transplant kit includes a custom-designed trephine for the production of RPE transplants, a carrier for storage and transportation, and a surgical device for subretinal delivery of RPE transplants. Cell viability assay confirmed biocompatibility of the transplant carrier and high preservation of RPE transplants upon storage and transportation. The transplant surgical device combines foldable technology that minimizes incision size, controlled delivery speed, no fluid reflux, curved translucent tip, usability of loading and in vivo reloading, and ergonomic handle. Furthermore, the complementary design of the transplant carrier and the delivery device resulted in proper grasping, loading, and orientation of the RPE transplants into the delivery device. Proof-of-concept transplantation studies in a porcine model demonstrated no damage or structural change in RPE transplants during surgical manipulation and subretinal deployment. Post-operative assessment confirmed that RPE transplants were delivered precisely, with no damage to the host retina or choroid, and no significant structural change to the RPE transplants. Our novel surgical kit provides a comprehensive set of tools encompassing RPE graft manufacturing to surgical implantation rendering key enabling technologies for pre-clinical and clinical phases of stem cell-derived RPE regenerative therapies.

An Ergonomic Neuroendoscopic Instrument Handle Design using 3D Printing.

Minimally invasive neurosurgery poses several challenges to surgeons due to constrained working environment, and its implications on the surgical outcome are an area of growing concern. The instrument handle design directly affects surgeon's performance, and the conventional ring handle causes ergonomic discomfort. The aim of this study was to design and validate a palm grasping-based ergonomic handle for skull-base neuroendoscopic instruments. The handle was designed based on the palm grasping technique and to naturally match the contours of hand. The ergonomic handle was fabricated and assembled with the end-effector of biopsy forceps. Fifteen participants with no experience of neuroendoscopic procedures validated the ergonomic handle. During data collection, participants performed the ring transfer task on straight, right tilt (+30°) and left tilt (-30°) of activity plates of neuro-endo-trainer (NET) with 0° and 30° endoscopes. Feedback from participants indicated that there was significant improvement in degree of discomfort in performing the task on straight (P = 0.006) and tilted plate (P = 0.001) and degree of pain (0.0001) using the ergonomic handle. Furthermore, video analysis of the performed task shows that there was statistical improvement in hitting events (P = 0.001, P = 0.04), tugging events (P = 0.00001, P = 0.00001,) and picking attempts (P = 0.04, P = 0.0004) on straight and tilted plates, respectively. There was reduction in ring drop, jerk, and average moving time, but results were not significant. The subjective validation of ergonomic handle by neurosurgeons shows that the designed handle offers ergonomic advantages. Objective validation by video analysis shows that the ergonomic handle results in better task performance on NET surgical trainer.

Use of a force measuring walker to optimize recovery after median sternotomy

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND Patients often need to use their arms to assist with functional activities, but after open-heart surgery, pushing with the arms is often limited to <10 lb (4.5 kg), to minimize force across the healing sternum. Restricting arm use often limits patient functional independence which can contribute to longer hospital stays and greater need for care after hospitalization. Therefore, appropriate arm use is important for return to function. Currently, no method exists to measure patient upper extremity weight bearing (UEWB) forces objectively in clinical settings. The ultimate goal was to develop a walker that provides UEWB force feedback to patients recovering from median sternotomy. This research project included three interrelated parts that sequentially built on each other. PART 1 First, I conducted a secondary data analysis comparing UEWB force and Pectoralis Major Muscle EMG during functional mobility in younger vs. older subjects (n = 65). Results showed that the mean arm force was >10 lb before feedback training during all functional mobility tasks for both groups. There were significant differences in UEWB force and EMG between groups (young vs. old) and trials (pre- vs. post-feedback training). There was significantly greater improvement (change) in the UEWB force in the older than younger subjects. We also found a significantly greater reduction in EMG activity in the older subjects than younger subjects for all tasks except during stand-to-sit. Results suggested that patients, particularly older ones, may not accurately estimate UEWB force <10 lb, and feedback training is effective for improving accuracy. This established proof-of-concept, the need for a Clinical Force Measuring (CFM) walker, and the efficacy of its use with feedback training. PART 2 Next, I completed a qualitative study to obtain critiques of a CFM walker prototype from rehabilitation professionals through structured interviews that were recorded and transcribed. I coded key statements and phrases that allowed "themes" to emerge (Table 1), which guided device revisions. PART 3 Lastly, I fabricated and tested a second CFM Walker prototype (Figure 1) based on key design elements including: 1) integrated vertical force measuring capability, 2) ergonomic handles, 3) simple visual and auditory feedback with upper limit alarms, 4) streamline, stable, and manoeuvrable frame, 5) lightweight construction, 6) minimal drag, 7) adjustable height, 8) ability to disinfect, and 9) affordable cost. CONCLUSIONS The CFM Walker could help patients recover safer and faster from open heart surgery, especially elderly adults.

PUI 사용성 개선을 위한 의료기기 손잡이의 인간공학적 평가: 이비인후과 진료장치를 중심으로

Objective: The purpose of this study is to ergonomically evaluate subjective usability according to handle shape, diameter, angle and button position for endoscope, and spray of the Ear, Nose, and Throat (ENT) medical device to suggest optimal design guidelines.<BR>Background: As medical demand increases, the prevalence of occupational diseases among doctors is high such as musculoskeletal and cerebral cardiovascular diseases. Therefore, it is required to design an ergonomic PUI (physical user interface) to minimize human mistakes and errors of a doctor in the medical system.<BR>Method: Forty subjects participated in this study. This study produced a mock-up of an endoscope and spray with various handle types, angles, and diameter. For the pen-type endoscope, the shape of the handle (cylindrical, rectangular) and diameter (32, 35, 38㎜) were considered as independent variables. For the pistol-type endoscope, the shape of the handle (cylindrical, rectangular) and angle (90°, 100°, 110°, 120°, 130°) were considered as independent variables. For the spray, the position of the button (upper-top, middle-front, middle-side, lower-front, lower-side) was considered as the independent variable. As a dependent variable, this study evaluated the subjective usability using by the visual analog scale on a scale of 0 to 100.<BR>Results: The ANOVA result of a pen-type endoscope, there were significant differences in handle shape and diameter. The handle shape of rectangular and 32mm diameter had the significantly highest usability. The ANOVA result of the pistol-type endoscope, the handle angle had the significantly highest usability at 120°. As the angle increased up to 120°, subjective usability also tended to increase, but the angle of 130° decreased the trend. The ANOVA result of spray, the position of push button had the significantly highest subjective usability on bottom-front.<BR>Conclusion: Based on the results of this study, the endoscope and spray should be designed to have a pistol-type cylindrical handle with a diameter of 32 to 35mm and an adjustable angle. If the adjustable design is difficult, it is suggested to design with an angle of about 120°. And also, it is suggested that the spray’s button be positioned in the front, which can be pressed with the thumb.<BR>Application: This study can apply ergonomic handle design guidelines for endoscopy and spray. Furthermore, it could contribute to the prevention of occupational musculoskeletal disorders.

Design and evaluation of a multifunctional surgical device for space-based applications

As NASA plans for extended and far-reaching space explorations with astronauts aboard, there is an inevitability of situations where medical/surgical intervention will be necessary (e.g. emergency appendectomy). Given the urgency of these situations juxtaposed with limited material resources on a spacecraft, economy and efficiency while maintaining safety and sterility during surgical interventions are critical. To address these needs, an integrated multifunctional surgical device (MFSD) was developed for space-based general surgical applications. A reduced-footprint, compact, ergonomic handle and a dual-lumen fluid transfer shaft were fabricated using fused deposition modeling (FDM) and direct metal laser sintering (DMLS), respectively. The device successfully integrates suction, irrigation, and illumination functionality through a single instrument via finger-tip control and has been validated on the benchtop and in a post-mortem animal study. The device will reduce blood loss and help maintain visualization by removing blood/debris from the operative field, while also minimizing the number of instruments and exchanges necessary during a procedure. The MFSD technology is compatible with the aqueous immersion surgical system (AISS), a fluidic control configuration currently in development for investigation of space-based surgical techniques, as well as conventional Earth-based systems for open and minimally invasive procedures.

Comparative Study of the Use of Different Sizes of an Ergonomic Instrument Handle for Laparoscopic Surgery

Previous studies have shown that the handle design of laparoscopic instruments is crucial to surgical performance and surgeon’s ergonomics. In this study, four different sizes of an ergonomic laparoscopic handle design were tested in a blind and randomized fashion with twelve surgeons. They performed three laparoscopic tasks in order to analyze the influence of handle size. Execution time, wrist posture, and finger and palm pressure were evaluated during the performance of each task. The results show a significant reduction in the time required to complete the eye-manual coordination task using the appropriate handle. The incorrectly sized handle resulted in a rise in palm pressure and a reduction in the force exerted by the thumb during the transfer task. In the hand-eye coordination task, the use of the right handle size led to an increase in middle finger pressure. In general, surgeons had an ergonomically adequate wrist flexion in all tasks and an acceptable radio-ulnar deviation during the transfer task using the ergonomic instrument handle. Surgeons found it comfortable the use of the ergonomic handle. Therefore, the use of an appropriately sized instrument handle allows surgeons to improve ergonomics and surgical performance during the laparoscopic practice.

Design and Evaluation of a Dexterous and Modular Hand-Held Surgical Robot for Minimally Invasive Surgery

Abstract Current surgical instruments with fewer degrees-of-freedom (DOF) for minimally invasive surgery (MIS) have limited capability to perform complicated and precise procedures, such as suturing and knot-tying. To address such a problem, a modular dexterous hand-held surgical robot with an ergonomic handle and 4DOF interchangeable instruments was developed. The kinematic arrangement of the instrument and that of the handle were designed to be the same. A compact roll-yaw-roll transmission was proposed applying cable-driven mechanism. Performance experiments were carried out to evaluate the effectiveness of the overall system. The measured grip forces of the robot ranged from 8.63 N to 19.18 N. The suturing performance score of the robot was significantly higher than that of the conventional instrument (28.8 ± 5.02 versus 17.2 ± 7.43, p = 0.041). The trajectory tracking test and animal experiment verified the accuracy and feasibility of the robot. The proposed robot could improve the surgical performance of MIS, providing various end-effectors and having an intuitive interface in the meantime.

Ex vivo Comparison of 2 Disposable versus a State-of-the-Art Reusable Ureterorenoscope

Introduction: The success of upper urinary tract endoscopy on one hand and the high cost of purchase and maintenance of the scopes on the other hand have driven the development of disposable digital flexible ureterorenoscopy (fURS). Materials and Methods: We performed an ex vivo comparison of 2 disposable digital fURS from different companies with a state-of-the-art reusable endoscope from another well-established scope manufacturer. The scopes were tested comparing parameters such as instrument handling, irrigation flow, image quality, and deflection. For the disposable scopes, the latter 2 were evaluated both, before and after vigorous stress testing. Results: Expectedly, the most consistent finding among the 3 instruments was the marked decrease on irrigation flow following insertion of a working element, most notably a guidewire. Depth perception and ergonomic handling were comparable in all 3 instruments. Poststress testing revealed a significant loss of upward deflection in both disposable instruments, more so when an auxiliary instrument is inserted into the working channel. However, this did not appear to be the case in downward deflection. Conclusions: To our knowledge, this is the first study that used a vigorous stress testing protocol comparing disposable and reusable fURS. The newer generation disposable scope fared better than the older one. Results are encouraging and indicate that improvements are ongoing and progressing, bringing the quality of disposable scopes to the level that we are used to from our reusable high performance scopes while at the same time avoiding costly damage repairs. Continuous research and evidence-based interpretation of results in the absence of commercial bias are paramount to ensure this ongoing development.

Design for Extremes: A Contour Method for Defining Requirements Based on Multivariate Extremes

AbstractThe design of various products is driven by requirements that describe extremes. In marine structural design, joint extremes of environmental variables like wave height and wind speed are used to define load cases. Similarly, in ergonomic design minimum and maximum values of anthropometric variables are considered to make sure a product is suitable for a wide range of users. Here, we present a method that supports designers to define requirements using joint extreme values: the requirements contour method. The method is based on structural engineering's environmental contour method and uses a dataset and statistical methods to specify a region in the variable space that must be considered in the design process. That region's enclosure is the requirements contour and holds the joint extremes. After formally describing the method, we give an illustrative example of its usage: we use it to define requirements for the design of an ergonomic handle for a power tool. The requirements contour method is a field-independent approach to design for extremes. In the tradition of design for X, we think that a design project can benefit from applying methods that focus on different 'X's.