Background:Coracoid process transfer for the treatment of recurrent glenohumeral dislocations is a safe and reliable procedure; however, there is no consensus as to which is the best method, the Bristow or Latarjet procedure.Purpose:To analyze the results of coracoid process transfer for the treatment of recurrent glenohumeral dislocations and to compare the results of this transfer between the Bristow and Latarjet techniques.Study Design:Systematic review; Level of evidence, 4.Methods:The databases surveyed for this review included J-STAGE; Cochrane Bone, Joint and Muscle Trauma Group Specialized Register; Cochrane Controlled Register of Trials; MEDLINE; Ovid; Embase; Google Scholar; and CINAHL. Inclusion criteria consisted of (1) studies related to anterior glenohumeral dislocations treated with transfer of the coracoid process to the anterior glenoid rim and (2) studies that could provide data to perform at least 1 meta-analysis or other statistical evaluation. Titles and abstracts were reviewed for inclusion; thereafter, outcomes and the risk of bias were extracted. Statistical analyses were performed according to the nature of the data. When possible, the 95% CI was included.Results:Of the 779 studies found, 63 were able to provide data assessing 3395 shoulders. There were no randomized, blinded, or double-blinded trials. The recurrence of dislocations was assessed in 41 studies that used the Bristow technique (n = 2346 shoulders; percentage redislocations [mean ± SE], 1.00% ± 0.20%) and 18 studies that used the Latarjet technique (n = 930 shoulders; percentage redislocations, 2.13% ± 0.49%) (P = .04). The mean loss of external rotation was 12.91° for the Bristow procedure (n = 1440 shoulders) and 11.70° for the Latarjet procedure (n = 243 shoulders). The mean quality-of-life outcome scores were as follows for the Bristow and Latarjet procedures, respectively: Rowe score, 92.06 and 89.33; Western Ontario Shoulder Instability Index score, 16.44% and 19.68%; Japanese Orthopaedic Association score, 93.28 and 92.00; and American Shoulder and Elbow Surgeons score, 91.00 and 89.90.Conclusion:Transferring the coracoid to the anteroinferior border of the glenoid through the subscapularis tendon is effective, regardless of the technique. When comparing the Bristow and Latarjet techniques, the recurrence of dislocations was the only outcome that could undergo a meta-analysis, and it presented a statistically significant difference in favor of the Bristow procedure. All other outcomes presented no clinically significant differences between their effect sizes. More studies presenting better methodology are still needed to achieve more robust conclusions.

In many state-of-the-art rotary blood pumps for long-term ventricular assistance, the impeller is suspended within the casing by magnetic or hydrodynamic means. For the design of such suspension systems, profound knowledge of the acting forces on the impeller is crucial. Hydrodynamic bearings running at low clearance gaps can yield increased blood damage and magnetic bearings counteracting high forces consume excessive power. Most current rotary blood pump devices with contactless bearings are centrifugal pumps that incorporate a radial diffuser volute where hydraulic forces on the impeller develop. The yielding radial forces are highly dependent on impeller design, operating point and volute design. There are three basic types of volute design--singular, circular, and double volute. In this study, the hydraulic radial forces on the impeller created by the volute in an investigational centrifugal blood pump are evaluated and discussed with regard to the choice of contactless suspension systems. Each volute type was tested experimentally in a centrifugal pump test setup at various rotational speeds and flow rates. For the pump's design point at 5 L/min and 2500 rpm, the single volute had the lowest radial force (∼0 N), the circular volute yielded the highest force (∼2 N), and the double volute possessed a force of approx. 0.5 N. Results of radial force magnitude and direction were obtained and compared with a previously performed computational fluid dynamics (CFD) study.

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Assuming that blood has a constant viscosity is a common practice when designing rotary blood pumps (RBPs), where shear stresses are generally higher than in the human body. This eases the design and allows numerical simulations and bench top experiments to be performed with Newtonian fluids. However, specific flow conditions may cause a change in cell distribution leading to an apparent lower blood viscosity. It has been observed that decreasing the vessel diameters and increasing flow velocities contribute to this effect. Because a hydrodynamic bearing operates under flow conditions following this pattern, it is important to verify whether this effect also takes place when this type of bearing is applied to a RBP. Because the operation of a hydrodynamic bearing depends directly on the fluid viscosity, a local change in cell distribution in the bearing gap can be reflected in changes in the bearing performance. In this work, a spiral groove hydrodynamic bearing was tested with porcine blood in a specially built test rig. The generated suspension force, cross flow, and bearing torque were recorded and compared with the reference response when using a solution of water and glycerol. Experiments with porcine blood yielded lower suspension forces, lower flows, and lower bearing torques than when using the glycerol solution. An explanation could be a lower apparent viscosity due to inhomogeneity of blood cell concentrations. Therefore, it is crucial to consider the effective blood viscosity when designing hydrodynamic bearings for RBPs and performing experiments.

The rapid evolution of rotary blood pump (RBP) technology in the last few decades was shaped by devices with increased durability, frequently employing magnetic or hydrodynamic suspension techniques. However, the potential for low flow in small gaps between the rotor and pump casing is still a problem for hemocompatibility. In this study, a spiral groove hydrodynamic bearing (SGB) is applied with two distinct objectives: first, as a mechanism to enhance the washout in the secondary flow path of a centrifugal RBP, lowering the exposure to high shear stresses and avoiding thrombus formation; and second, as a way to allow smaller gaps without compromising the washout, enhancing the overall pump efficiency. Computational fluid dynamics was applied and verified via bench-top experiments. An optimization of selected geometric parameters (groove angle, width and depth) focusing on the washout in the gap rather than generating suspension force was conducted. An optimized SGB geometry reduced the residence time of the cells in the gap from 31 to 27 ms, an improvement of 14% compared with the baseline geometry of 200 μm without grooves. When optimizing for pump performance, a 15% smaller gap yielded a slightly better rate of fluid exchange compared with the baseline, followed by a 22% reduction in the volumetric loss from the primary pathway. Finally, an improved washout can be achieved in a pulsatile environment due to the SGB ability to pump inwardly, even in the absence of a pressure head.

To date, ventricular assist devices (VADs) have become accepted as a therapeutic solution for end-stage heart failure patients when a donor heart is not available. Newer generation VADs allow for a significant reduction in size and an improvement in reliability. However, the invasive implantation still limits this technology to critically ill patients. Recently, expandable/deployable devices have been investigated as a potential solution for minimally invasive insertion. Such a device can be inserted percutaneously via peripheral vessels in a collapsed form and operated in an expanded form at the desired location. A common structure of such foldable pumps comprises a memory alloy skeleton covered by flexible polyurethane material. The material properties allow elastic deformation to achieve the folded position and withstand the hydrodynamic forces during operation; however, determining the optimal geometry for such a structure is a complex challenge. The numerical finite element method (FEM) is widely used and provides accurate structural analysis, but computation time is considerably high during the initial design stage where various geometries need to be examined. This article details a simplified two-dimensional analytical method to estimate the mechanical stress and deformation of memory alloy skeletons. The method was applied in design examples including two popular types of blade skeletons of a foldable VAD. Furthermore, three force distributions were simulated to evaluate the strength of the structures under different loading conditions experienced during pump operation. The results were verified with FEM simulations. The proposed two-dimensional method gives a close stress and deformation estimation compared with three-dimensional FEM simulations. The results confirm the feasibility of such a simplified analytical approach to reveal priorities for structural optimization before time-consuming FEM simulations, providing an effective tool in the initial structural design stage of foldable minimally invasive VADs.

Abstract. Robotics has played an increasingly important role in several sectors of the society. Nowadays, robots are not only used to support activities in factories, but also to assist house cleaning, border surveillance, and even surgeries. The variety of application domains and the rising complexity are challenging the design of robotic systems that control such robots. In this perspective, Service-Oriented Architecture (SOA) has been adopted as a promising architectural style to design large, complex robotic systems in a flexible and reusable manner. Several Service-Oriented Robotic Systems (SORS) have been developed in the recent years and a large number of services are available for reuse. Nevertheless, none of the environments dedicated to the development of SORS provide an efficient mechanism for publishing and discovering services. As a consequence, services for SORS have to be manually searched, reducing significantly the potential of reuse and productivity provided by SOA. This paper presents RoboSeT, a mechanism that supports cataloging and discovery of services for robotic systems. RoboSeT is based on semantic search and classifies the services using a taxonomy of the robotics domain. Results of our case study indicate that RoboSeT facilitates the development of robotic systems, since it presents the potential to widely promote reusability of services for SORS.

Massive rotator cuff tears, involving the posterosuperior rotator cuff, remain difficult to treat particularly in the younger population. Fatty infiltration of the muscle, excessive chronic tendon retraction, and degeneration are the main irreversible factors predisposing to high failure rates of direct repair. There are many techniques for Superior Capsular Reconstruction (SCR) mainly using allograft. However low accessibility to the dermal grafts in many countries led the authors to use and suggest autograft of the fascia lata as other option for the reconstruction of the superior capsule of the shoulder. The SCR have presented good functional and biomechanical results. These techniques are reliable options for irreparable lesions of the rotator cuff.