Trainees in orthopedic surgery are required to receive dedicated laboratory-based surgical skills training in their first year of residency. Simulators are often used in this training. Our group previously developed a hip fracture wire navigation simulator to train and assess skill in placing a K-wire within a femur bone surrogate using synthetic fluoroscopic images to aid in navigation. In this paper, we describe design considerations and challenges in modifying the existing simulator to enable the training of multi-wire pinning of a pediatric supracondylar humerus fracture. The design involves changing the bone of interest from the adult femur to the pediatric humerus, while using the same platform technology. Considerations include ease of use, minimizing motion of the fixed bone, and minimizing materials used. The robustness of the bone mounting was tested by running an experiment using 3D scans and surface deviation analysis to test repeatability of bone placement and its resistance to rotational motion after being placed in the fixture. After the new design was shown to hold the bone rigidly, a pilot study of the new simulator was conducted to confirm that the surgeons and residents consider the simulator experience as being a valid representation of the actual surgical skill.

A study to determine the optimal insertion point of the latissimus dorsi muscle for treatment of rotator cuff tears using in-silico biomechanical models. A cadaver trial was used to validate the simulation results. The optimal area for insertion for improving glenohumeral rotation throughout a range of flexion was found to be the center of the greater tuberosity.

Laparoscopic surgery offers multiple clinical advantages over open surgical procedures. The rise in adoption of laparoscopic surgery brings with it unique human factors challenges for surgeons and device developers. The design of laparoscopic surgical tools requires specialized human factors analysis and ergonomic considerations to overcome these challenges. Often, this necessary ergonomic design refinement is a secondary effort after proof-of-concept engineering prototypes demonstrate technological feasibility. In this paper, the evaluation and redesign of an engineering proof-of-concept multimodal hand tool, is presented. The baseline design, a three-in-one laparoscopic hand tool for liver resection, merged three distinct devices into one integrated solution for dissection, vessel sealing, and tissue cautery. The work described herein evolves the initial prototype using a multifaceted human factors analysis and design process. This included the use of operating room and laboratory contextual inquiry, simulated use studies, anthropometric underlays, an iterative design process, and expert reviews. The revised design reduced ulnar deviation based on directed hand position via design, provided dual grip options, added over-molded interaction points, incorporated end-effector rotation, and implemented a new handle and controls layout based on anthropometric underlays. The outcome reinforces the notion that human factors and industrial design principles are required elements of a successful user centered design process.

An improved tool for operative vaginal delivery can reduce maternal and fetal trauma during the delivery and recovery processes. When a delivery cannot be completed naturally due to maternal exhaustion or fetal distress, physicians must perform an operative vaginal delivery (OVD), with forceps or a vacuum, or a Cesarean section (C-section). Although C-sections are more prevalent in the United States than OVDs, they require longer maternal hospital stays and recovery time and increase risk of maternal infection and fetal breathing problems [1]. In 2015, the American College of Obstetrics and Gynecology pushed to increase the number of OVDs to limit C-section associated delivery risks [2]. However, the current tools for OVD either have steep learning curves, are unable to be used for all fetal head presentations, or have associated maternal and fetal risks [3][4]. There is a need for an easy to use, safe, and reliable tool for operative vaginal delivery.

Vacuum-assisted biopsy (VAB) is a widely used technology to sample lesion tissue for breast cancer diagnosis. The technology is designed to retrieve tougher and larger breast tissue samples. The majority of VAB tools utilize a so-called rotational cutting method, in which the cutting needle simultaneously rotates and translates to produce both tangential and normal forces at the cutting surface of the tissue. The introduction of the tangential force can significantly reduce the cutting force measured in the axial direction. As a result, higher quality of tissue samples can be obtained as the samples are less deformed while being removed. The slice-push ratio, i.e. the ratio of the speed component parallel to the cutting edge to the speed component perpendicular to the cutting edge, was previously found to be the most important factor to influence the cutting force [1]. However, these studies only investigated the cases in low translational cutting speeds in a small-scale experiment. In this paper, we present a finite element (FE) model based on surface-based cohesive behavior, which simulates the rotational cutting method used in VAB to predict the progressive damage and the cutting force of soft tissue phantoms. The model is validated using the experimental data provided in the previous study [1]. The validated model will allow us to explore more cutting conditions, such as higher translational speeds, larger range of slice-push ratio, and tissue properties. The model can also be used to optimize design parameters of current VAB needles and to evaluate new VAB needle designs.

Breast lesion tissue can be extremely stiff, e.g. calcification or soft, e.g. adipose. When performing needle biopsy, too small or scanty samples can be retrieved due to the tissue is mainly compressed instead of being cut. In order to studying the tissue cutting performance in various cutting conditions, tissue-mimicking phantoms are frequently used as a surrogate of human tissue. The advantage of using tissue phantoms is that their mechanical properties can be controlled. The stiffness of a tissue phantom can be measured by an indentation test. Previous studies have demonstrated mathematic models to estimate Young’s moduli of tissue phantoms from force-displacement data with an adjustable coefficient according to the geometry of the indenter. Tissue force reactions occurred needle insertion has been largely researched [1], but few studies investigated the tissue cutting with a rotational needle, which is a cutting method largely used in the breast needle biopsy. Research has demonstrated that the influence of rotation can significantly reduce the insertion force [2], but the experiment was conducted on a specific formula of silicone-based tissue phantoms. This paper served as a pilot study of a large-scale experiment to study the effect of rotational cutting on various cutting conditions and target materials, including artificial and biological soft tissues. Two most common types of soft tissue phantoms, biopolymers (gelatin gels and agar) and chemically synthesized polymers (polydimethylsiloxane, PDMS) were investigated. Indentation tests were performed to estimate the mechanical properties of tissue phantoms which were then verified by finite element simulations. Tissue cutting tests with and without rotation were conducted to evaluate the effect of needle rotation on the tissue force reactions.

Prostate cancer is the most common cancer among males, leading to approximately 27,000 deaths in the United States [1]. Focal laser ablation (FLA) has been shown to be a promising approach for prostate cancer treatment with the advantage of efficiently ablating the cancer cells while inflicting less damage on the surrounding tissues. In current FLA procedures, a rigid template — with holes spacing of 5mm — guides the FLA catheter to the target position. Drawbacks of the conventional approach for catheter targeting are 1) limited degrees of freedom (DoF) and 2) a low insertion resolution. In addition, the targeting capability of the rigid template is compromised when the pubic arch or nerve bundles intersect the catheter trajectory. We hypothesized that a compact design of an MRI-conditional robot with two active planar DoFs, one passive rotation DoF, and remote catheter insertion capacities could enhance the clinical workflow required for MRI-guided FLA prostate procedures.

In Amyotrophic Lateral Sclerosis (ALS), neurons controlling voluntary muscles die, resulting in muscle weakness. Small animal studies have shown that neurons experience some regeneration when stem cells are injected into the ventral horn of the spinal cord [1]. These results led to large animal and human trials investigating the effects of injecting stem cells into the spinal cord. Direct injection is used for delivering cells as cells do not have to migrate to the therapy site and visual confirmation is possible [2]. This requires a multi-level laminectomy as well as dissection of the dura mater to expose the cell delivery site. In order to adopt this ALS treatment in regular clinical workflow, a minimally invasive alternative for spinal cord cell therapy is desirable. Image-guided needle targeting and positioning systems have been developed by numerous groups which use computed tomography or ultrasound for image guidance. However, MRI must be used for this ALS study because it is the only imaging system capable of visualizing the necessary anatomical locations for delivering cellular therapeutics to the spinal cord; the cell therapy target is the gray matter within the ventral horn of the spinal cord, and only MRI can detect the contrast between gray and white matter. Innomotion and NeuroArm have been used for MRI-guided interventions [3, 4] but they are complex, take a long time to set up, and take up a great deal of space in the MRI bore. An initial solution by our research group provided targeting solutions using an adjustable template on the spine, but was manually adjusted, targeted solely on a grid, and lacked a second rotation axis[5]. The presented device, SpinoBot, percutaneously directs therapeutics under MRI guidance into the spinal cord, allowing accurate and minimally invasive spinal therapies. This study examines the accuracy and workflow of MRI-guided cellular therapeutics injections using SpinoBot, a targeting and injection needle guidance system.

Over the past decade, natural orifice transluminal endoscopic surgery (NOTES) has developed out of a merger of endoscopy and surgery [1]. NOTES offers the advantages of avoiding external incisions and scars, reducing pain, and shortening recovery time by using natural body orifices as the primary portal of entry for surgeries [2]. The NOTES platform consists of a flexible, hollow body — enabling travel in the interior of the human body — and the distal end (head), the mechanical structure of which is based off of the snake bone. After the distal end passes through a natural orifice, through a transluminal opening of the stomach, vagina, bladder, or colon, and reaches the target working place in the peritoneal cavity, several therapeutic and imaging tools can be passed through the hollow conduit of the NOTES’ body for surgeries [3]. The traditional snake bone design presents two major problems. First, the movement is constrained to two bending degrees-of-freedom (DOF). A need to reorient the tool then often requires the entire body to be rotated by the physician, an unwieldly manipulation that both hinders convenience and results in imprecise control. Second, the traditional fabrication process is tedious and therefore lends to higher manufacturing costs; the bending joints must be first individually machined then assembled together piece-by-piece using rotation pins. We propose a novel design for the snake bone that introduces an additional DOF via rotation and is simple and cost-effective to machine. The revised snake bone design features rotation segments controlled by wires that a physician can readily manipulate for increased control and convenience. Further, because surgical tools that pass through the NOTES body conduit are also installed on snake bone structures, the introduction of rotation to the snake bone design increases each tool’s mobility and manipulation. This advance therefore presents the potential to decrease both the number of required tools and the overall diameter of the NOTES body. Finally, the body is machined as a single element and therefore minimizes the work of assembly.

Cardiovascular diseases including atherosclerosis, thrombosis, aneurysm and arrhythmia remain the major cause of mortality in developed countries, accounting for 34% of deaths each year [1]. Commonly used minimally invasive vascular intervention with using catheters leads to higher success rate than open surgery [2]. Integrating robotic technologies into active control of catheters in teleoperation manner has promised to reduce radiation exposure to surgeons and improve accuracy during electro-physiological (EP) procedures [1]. Common used commercial robotic EP catheter platforms such as Sensei (Hansen Medical Inc., USA) and Niobe (Stereotaxis Inc., USA) are usually composed of a catheter driver (slave side) which can be remotely controlled by a console operator (master side). However, the Sensei catheters are more rigid and bigger than standard catheters because of their two-layer-sheath structure; and Magnetic Niobe systems are huge and expensive. In this paper, we propose a mechanism of remote-driving catheterization platforms in which a commercial tip-steerable ablation catheter (St. Jude Medical Inc., USA) (Fig. 1) is manipulated by a catheter driver in three degree of freedoms (DOF) (insertion/withdrawal, rotation and tip deflection). In addition, we also present the design of the control software based on Object-Oriented Programming (OOP) method which is expected to give the other researchers a guide line during robotic catheter design.

In clinical settings, doctors classify pulmonary disorders into two main categories, obstructive lung disease and restrictive lung disease. The former is characterized by the airway obstruction which is associated with several disorders like chronic bronchitis, asthma, bronchiectasis, and emphysema [1]. The latter is caused by different conditions where one of the triggers is tied to the spine deformity. In general, a pulmonary function test (PFT) [2] is used to evaluate and diagnose lung function, and physicians depend on the test results to identify the disease patterns of the patients (obstructive or restrictive lung disease). In the PFT, some parameters including total lung capacity (TLC), vital capacity (VC), and residual volume (RV) can infer the lung volume and lung capacity. Other parameters, such as forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1), are often employed to assess the pulmonary mechanics. Scoliosis is an abnormal lateral curvature of the spine which involves not only the curvature from side to side but also an axial rotation of the vertebrae. Restrictive lung disease often happens in scoliosis patients, especially with severe spine deformity. Spine deformity if left untreated may lead to progression of the spinal curve, respiratory complications, and the reduction of life expectancy due to the decrease in thoracic volume for lung expansion. However, the relationship between thoracic volume and pulmonary function is not broadly discussed, and anatomic abnormalities in spine deformity (ex: scoliosis, kyphosis, and osteoporosis) can affect thoracic volume. Adequate thoracic volume is needed to promote pulmonary function. Previous literature has shown that the deformity of the thoracic rib cage will have detrimental effects on the respiratory function in adolescent idiopathic scoliosis patients [3–4]. In this paper, we aim to correlate thoracic volume and the parameters in PFTs in adult scoliosis patients 25–35 years after receiving treatments during their adolescence, either with physical bracing or spinal fusion surgery.

Posterolateral corner (PLC) injury of the knee causes varus and posterolateral rotatory instability. The anatomy of the PLC has been reported in the literature but the importance of PLC reconstruction has only recently been established and ideal reconstruction techniques are still in development. The native function of the PLC is to restrain varus and external rotation. Reconstruction methods should properly restore these functions without overconstraining the joint. Several reconstructions for PLC injury have been reported but with concerns of iatrogenic neurovascular injury, fibular head cutout, and restoration of the knee kinematics. To address these concerns, a new cross fibula tunnel method was developed that may have lower risk of iatrogenic nerve injury and fibula head cutout. The purpose of this study was to verify the stability of this technique using a PLC deficient knee.

Objective: Long term clinical data showed that lumbar fusion for Lumbar spinal stenosis (LSS) and lumbar disc degeneration (LDD) therapy could change the loads of disc and articular facet and increase the motion of adjacent segments which lead to facet arthropathy and adjacent level degeneration. This study is to design and analyze an interspinous process device (IPD) that could prevent adjacent level degeneration in the LSS and LDD therapy. Method: The IPD was designed based on anatomical parameters measured from 3D CT images directly. The IPD was inserted at the validated finite element model of the mono-segmental L3/L4. The biomechanical performance of a pair of interbody fusion cages and a paired pedicel screws were studied to compare with the IPD. The model was loaded with the upper body weight and muscle forces to simulate five loading cases including standing, compression, flexion, extension, lateral bending and axial rotation. Results: The interbody fusion cage induced serious stress concentration on the surface of vertebral body, has the worst biomechanical performance among the three systems. Pedicle screws and interbody fusion cage could induce stress concentration within vertebral body which leads to vertebral compression fracture or screw loosening. Regarding to disc protection, the IPD had higher percentage to share the load of posterior lumbar structure than the pedicel screws and interbody fusion cage. Conclusion: IPD has the same loads as pedicle screw-rod which suggests it has a good function in the posterior stability. While the IPD had much less influence on vertebral body. Furthermore, IPD could share the load of intervertebral discs and facet joints to maintain the stability of lumbar spine.

Overhead throwing athletes have been shown to develop adaptive changes in humeral rotation to allow for higher throwing velocities. This manifests as an increase in humeral external rotation and a decrease in internal rotation, which is called glenohumeral internal rotation deficit (GIRD). The percentage of GIRD that significantly affects glenohumeral joint kinematics is not known. The objective of the study was to create a throwers shoulder model with fixed percentages of GIRD to determine at which point kinematic changes start occurring. The results showed that there was a significant decrease in posterior translation starting at 10% GIRD. With inferior translational loads, significantly less inferior translation starts occurring at 20% GIRD. The humeral head apex position at maximum external rotation moves superiorly, posteriorly and laterally, with significant changes in the superior direction occurring with 10% GIRD onwards. Overall, significant kinematic changes begin at 10% GIRD and this should be taken into account for clinical decision-making as to when intervention is necessary.

Surface registration is a necessary step and widely used in medical image-aided surgery. It’s relevance to medical imaging is that there is much useful anatomical information in the form of collected surface points which originate from complimentary modalities. In this study, the kinematic relations between two point clouds with different coordinate definitions have been generated. Using Influence Method of surface modeling for extracting point clouds functions, the transformation matrix would be resulted. The proposed method was applied for an experimental femur data points (651 points) using the MRI images. These data points were transformed in a 30 degrees flexion of knee. This transformation contains [0,−9.5, 1] degrees for yaw, pitch and roll rotation and [−3, 14,−13] translation. The related results shows [0, 9.3, 0.95] degrees for rotation and [−2.85, 14.11,−13.07] translation.

Microelectromechanical systems (MEMS) have great potential for use in gastrointestinal (GI) imaging. Ultrasound and magnetic resonant imaging can provide useful information about the GI tract, but only optical coherence tomography (OCT) delivered endoscopically can be used to perform an optical biopsy of the GI tissue. In monitoring a condition such as Barrett’s esophagus, which typically requires regular random biopsies, the ability to achieve an optical biopsy is indispensible. While the existing method for obtaining an optical biopsy of the GI tract tissue produces functional images, there are drawbacks that could be improved upon. The gear-and-shaft assembly used to couple force from the motor at the proximal end to the distal imaging end requires a complex design [1]. By introducing a rotational MEMS device into the distal imaging end, a rotating optical coupling joint is no longer required at the proximal end, there is no need to precisely align the fixed fiber with the rotational drive shaft, and the metallic reinforcement sleeve can be eliminated leaving a simpler, more flexible delivery method [2]. In order to produce 3D OCT images, displacement in the z-direction needs to be coupled with rotation. A MEMS device that can achieve both vertical displacement and rotation further increases the simplicity of the device and decreases potential alignment and coupling errors. Our MEMS devices needs to be able to bend an OCT beam of light 90°, rotate that beam of light 360°, and simultaneously scan in the z-direction in order to produce 3D OCT images. Also, the device must fit inside the 1 mm diameter available in the endoscope. To accomplish this, we have designed, and are continuing to develop, a paraffin actuated micro mirror. The thermal expansion properties of paraffin wax have often been utilized in MEMS devices [3, 4]. We have made use of these properties in designing a piston like actuator. Heat is applied to a reservoir of paraffin enclosed by a parylene membrane. The paraffin expands and pushes the post above it upward with the developed force from its expansion. The amount of paraffin in each reservoir is controlled by the reservoir’s geometry and so by controlling the amount of heat applied, we can control how far the post above it moves in the vertical direction. Each device has three heaters, three reservoirs, and three posts. All three posts are attached to a single mirror. By appropriately cycling the applied heat to each reservoir, we expect to be able to move the mirror in a spiral like fashion. This will bend an applied beam of light 90° and rotate it 360° while achieving displacement in the z-direction.

This talk will discuss venture capital trends globally and specifically how these trends are impacting the orthopedic market. The discussion will include: a. Current areas of interest in the venture community — i. Spin, ii. Knee/Hip, iii. Extremities/Small Bone; b. Choosing a financial partner; c. How to approach venture firms — i. Stage focus and how it impacts the entrepreneur, ii. General investment criteria; d. Making the pitch — i. How to make contact, ii. Key content/format, iii. Who is going to read what?, iv. Preparing for success, v. Market size, vi. Team, vii. Cap table, viii. All about milestones; e. Alternative funding sources; f. The costs associated with other people’s money.

We analyzed the kinematics of two rotating platform total knee replacement designs using KneeSIM, a commercially available computer code (LifeModeler, San Clemente, CA) in which we could manipulate the location of the axis of rotation of the rotating bearing.

This paper describes a design process for a new pediatric ventricular assist device (VAD), the PediaFlow. The VAD is a magnetically levitated turbodynamic pump design for chronic support of infants and small children. The design entailed the consideration of multiple pump topologies, from which an axial mixed-flow configuration was chosen for further optimization via computation fluid dynamics. The magnetic design includes permanent-magnet (PM) passive bearings for radial support of the rotor, an actively controlled thrust actuator for axial support, and a brushless DC motor for rotation. These components are closely coupled both geometrically and magnetically, and were therefore optimized in parallel, using electromagnetic, rotordynamic and fluid models. Multiple design objectives were considered including efficiency, size, and margin between critical speed to operating speed. The former depends upon the radial and yaw stiffnesses of the PM bearings. Analytical expressions for the stiffnesses were derived and verified through FEA. A toroidally-wound motor was designed for high efficiency and minimal additional negative radial stiffness. The design process relies heavily on optimization at the component-level and system-level. The results of this preliminary design optimization yielded a pump design with an overall stability margin of 15 percent, based on a pressure rise of 100 mmHg at 0.5 lpm running at 16,000 RPM.

We sought to determine the effects of head rotation, lateral neck flexion, and traction force on brachial plexus (BP) nerve strain, specifically at C5-C6 (Erb’s point), and C7, C8, and T1 roots in a multi-“filament” 3D model of the fetal BP. Using our constructed simulator and a tailored data acquisition system, strain readings were recorded and accurate to within <2%. Using our model and a position-sensing system, controlled loads and deformations were applied to a fetal head attached to a flexible spine. For each simulation, we measured BP strain at Erb’s point, and C7, C8, and T1 roots. Increasing total traction force increases strain in the upper and middle nerves (Erb’s point, C7, and C8). Lateral neck flexion produces the most strain (up to 25.4±6.6% in Erb’s point with 4.5 kg (10 lbs) of traction), with concomitant head rotation magnifying strain levels by up to a factor of 1.7. Increasing head rotation and lateral neck flexion increases the strain in the lower nerve roots more than in the upper roots. in general, upper nerves undergo double the strain of lower nerves. Direct axial traction has the least effect, with 4.5 kg of traction producing a peak strain of 3.6±2.5% at Erb’s point. BP strain can be reduced at Erb’s point, C7, and C8 by maintaining neutral alignment between the head and trunk prior to applying traction, which should be minimized.