bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational Simulations of the Anterior Vertebral Surface for Optimal Surgical Instrumentation Design
Authors: Casesnoves Francisco
Published: August 2010

The engineering design of surgical instrumentation to apply mechanical forces and linear moments on the human bones during the operations constitutes a rather difficult task. This is due both to the natural and pathological irregularities of the human bone morphology and surfaces and also to the individual variations from one patient to another. Usually, the forces are applied by the surgeon only on a determined part of the bone surfaces. This paper describes an innovative computational design method to digitalize, simulate, and fit mathematically the anterior vertebral body facet. We used real experimental data from 17 human cadaveric specimens to get and store a large amount of numerical surface digital values. The complete anterior vertebral body side was visualized and analyzed with grid data Subroutine, which was also used first to select the so-called natural regions of interest (ROIs). These ROIs correspond to those parts of the surface in contact with the surgical instrumentation, where the mechanical forces are applied. Subsequently, a numerical mathematical fitting-model was implemented for these ROIs. This was carried out with the development of a 3D geometrical least-squares optimization algorithm and appropriate software designed according to the proper numerical method selected. In doing so, the 3D superficies equations of the anterior vertebral body (L3, L4, L5, and S1) were determined after these fittings were mathematically checked as appropriate. Statistical parameters and determination coefficients that define the error boundaries and the goodness of this optimal fitting-model were calculated and NURBS error data in similar studies were commented. It was proven that the principal source of error was the micro- and macro-irregularities of human bone facets. The final surface equations, and their geodesics, were used to obtain accurate data for the spinal surgery instrumentation manufacturing. The industrial bioengineering result was the application of these equations for the design of a new spinal vertebral surgical distractor. This innovative distractor separates two adjacent vertebrae while keeping them parallel. That is, at their natural inclination, avoiding hammering the vertebrae to make the intervertebral space wider. The device mechanics also minimizes the necessary force to be carried out by the surgeon during the operation.
Automatic Vibrotactile Device for Interruption of Apnea in Premature Infants
Authors: Payombar Mojgan , Vera Fernando , Marayong Panadda
Published: August 2010

Apnea in premature infants is a common medical problem faced daily by neonatal intensive-care unit staff worldwide. The condition is defined as a pause in breathing that lasts for 20 s or longer and is traditionally treated by manual simulation administered by a nurse. This work proposes a design of an automatic apnea interruption system for infants, which utilizes a noninvasive vibrotactile (vibration feedback) unit to replace the traditional manual stimulation. The overall system consists of a vibrotactile unit and a device/user control interface that are used with a commercial patient monitoring device. The system monitors physiological signals associated with apnea, such as heart rate and blood oxygen level, and activates the vibrotactile unit in a closed-loop fashion. The system provides multimode haptic feedback for individualized patient treatment by allowing the care provider to adjust the magnitude and duration of the tactile stimulation from the user interface. As a preliminary evaluation, the system is tested for safety and performance using simulated data.
Design and Development of an Optical System for 3D Direct Detection of Dental Arch Model From the Patient’s Mouth
Authors: Nudo Paola , Perrelli Michele , Danieli Guido A.
Published: August 2010

This paper describes a 3D scanning system based on an active vision method using structured light in order to obtain the CAD model of a dental arch. Presently, dental prosthesization requires long times in between detecting the shape of the dental arch, plaster model generation, scanning of it, prosthesis preparation, and implant. The situation is even worse when use of dental implants is required, while early loading of the implants is considered a positive solution. For this reason many devices are actually presented for the intra oral determination of the shape of dental prostheses and inserts. These devices however are able to detect limited portions of the dental arch, since they must be hand held by the doctor. This work presents a new device able to detect with high precision the entire dental arch.
Design of an Endoscopic Biopsy Needle
Authors: Niebel Casandra , Frecker Mary
Published: August 2010

This paper summarizes the design and testing of a biopsy needle to be used through a flexible endoscope. There is a need for a biopsy needle that can be used through the endoscopic channel to perform zero invasive biopsies on the gastrointestinal system and other organs. In this project, a novel biopsy needle is designed, tested, and compared with an Olympus EZShot single use aspiration needle. The new needle was found to have a higher ratio of mass removed versus removal force.
Gravity Balancing Conditions for an Upper Arm Exoskeleton
Authors: Dubey Venketesh , Agrawal Sunil
Published: August 2010

An upper-arm wearable exoskeleton has been designed for assistance and functional training of humans. One of the goals of this design is to provide passive assistance to a user by gravity balancing, while keeping the transmitted forces to the shoulder joints at a minimum. Consistent with this goal, this paper addresses the following questions: (i) an analytical study of gravity balancing design conditions for the structure of the human arm, (ii) minimization of transmitted shoulder joint forces while satisfying the gravity balancing conditions, and (iii) possible implementation of these conditions into practical designs using zero-free length springs.
Human-Device Interface in Catheter Based Interventions
Authors: Privitera MaryBeth , Wirtz Micheal , Abruzzo Todd , Ringer Andrew , Nelson Stephen
Published: August 2010

Systematic methods for descriptive analysis of physician hand movements during surgical or catheter based interventions have not been previously reported. Although such data would provide critical guidance in the design of surgical instruments, there is currently little to no information about the chronological and spatial integration of operator movements and user conditions during catheter based interventions. The essential function of the hand is to provide physical coupling between the cognitive process and the environment, translating intention to action. The ideal surgical instrument is a contiguous extension of the haptic unit (the hand) that enables an expanded range of effector actions and environmental effects. In reality, however, there is an interface between the hand and the surgical instrument creating a barrier that can introduce variable levels of interference and impedance between the cognitive process and the intended task. The objective of this project is to analyze surgical effector outputs as a function of operator psychomotor inputs using synchronized multimodal image data recorded during clinical cases of transcatheter neurological intervention. Research methodology consisted of observations and digital recording (video and/or still photography) of 24 diagnostic cerebral angiograms. These were analyzed to synchronously document physician hand movement, surgical effector output (as represented by the fluoroscopic image monitor), spatial orientation feedback (as represented by rotational movements of the fluoroscopic imaging plane with respect to patient anatomical axes), and to identify user specific conditions. The results are presented in a defined procedure map and user behaviors based upon physician experience (e.g., fellow/trainee versus attending physician). As stated in the Association for the Advancement of Medical Instrumentation HE 75 human factors standards for medical device design, there is a clear need to develop human factors standards for endovascular devices. This research will serve as a guide to this effort. The models and multimodal image database generated by this project will also be used in the development of interactive educational tools to train physicians to perform these advanced applications.
Design of a Multifunctional Forceps for Use in Endoscopic Surgery
Authors: Rau Andrew , Frecker Mary , Mathew Abraham , Pauli Eric
Published: August 2010

This paper presents a 3.0 mm diameter endoscopic forceps design for use in minimally invasive surgical procedures, which require significant grasping and spreading forces. Models of the proposed design predict considerable improvements in the opening range (140%) and force application (87%) for both grasping and spreading when compared with currently used endoscopic forceps. Several of the tool’s design characteristics promote fail-safe malfunctions, including locking before catastrophic failure and the decreased likelihood in detached parts. Initial benchtop testing showed good agreement between prototype performance and model prediction. Frictional losses experienced during testing were found to depend on load orientation. A surgical prototype is currently being manufactured for ex vivo testing.
Design and Prototyping of a Low-Cost Portable Mechanical Ventilator
Authors: Al Husseini Abdul Mohsen , Lee Heon Ju , Negrete Justin , Powelson Stephen , Servi Amelia Tepper , Slocum Alexander H. , Saukkonen Jussi
Published: August 2010

This paper describes the design and prototyping of a low-cost portable mechanical ventilator for use in mass casualty cases and resource-poor environments. The ventilator delivers breaths by compressing a conventional bag-valve mask (BVM) with a pivoting cam arm, eliminating the need for a human operator for the BVM. An initial prototype was built out of acrylic, measuring 11.25×6.7×8 in.3 and weighing 9 lbs. It is driven by an electric motor powered by a 14.8 VDC battery and features an adjustable tidal volume up to a maximum of 750 ml. Tidal volume and number of breaths per minute are set via user-friendly input knobs. The prototype also features an assist-control mode and an alarm to indicate overpressurization of the system. Future iterations of the device will include a controllable inspiration to expiration time ratio, a pressure relief valve, PEEP capabilities, and an LCD screen. With a prototyping cost of only $420, the bulk-manufacturing price for the ventilator is estimated to be less than $200. Through this prototype, the strategy of cam-actuated BVM compression is proven to be a viable option to achieve low-cost, low-power portable ventilator technology that provides essential ventilator features at a fraction of the cost of existing technology.
A Case Study of Physician Interaction in the Medical Device Development Process
Authors: Shluzas Lauren Aquino , Linehan John H. , Leifer Larry J.
Published: August 2010

A multiphase empirical field study is being conducted at Stanford University to examine the process of physician interaction during medical device development. The initial component of this study involved creating an analytic framework for case-based research that provided a conceptual guide for the pilot case study documented in this paper. The pilot case study examined the process of engaging physicians in medical device development within the context of an entrepreneurial device company. The methods used in this study included a combination of interviews with cross-functional team members, a quantitative survey, and the collection of archival data. Data analysis first involved documenting physician-developer interaction practices that had been used within the company, from needs finding to post-market surveillance, across multiple product generations. Leading development factors involving physicians that had influenced the company’s clinical and financial outcomes were next identified. The case study illustrated the importance of working with and understanding the user experiences of a wide range of physicians when developing new products. The case also captured how physician interaction influences risk perceptions toward medical device performance for both surgeons and developers. The case likewise highlighted the benefits of a systems-based design approach, as opposed to designing products for a single technical end point. From a methodological perspective, the case study revealed the importance of examining user interaction within a contextual framework, as opposed to an isolated examination of input and output variables. The study presented in this paper has provided a foundation for future case-based analyses regarding the process of physician interaction in medical device development.
Steerable Laparoscopic Cable-Ring Forceps
Authors: Breedveld Paul
Published: August 2010

Laparoscopic surgery is carried out using long and slender endoscopes and instruments that are inserted through small incisions in the abdominal wall. Current endoscopes and instruments are rigid and have the drawback that their motion is restricted to 4-degrees of freedom (DOF). This paper describes a 6-DOF steerable laparoscopic grasping forceps incorporating a novel and very simple “cable-ring” mechanism consisting out of a ring of cables surrounded by two coil springs. Methods are described to increase stiffness and to improve manual control, resulting in a well-working prototype suitable for commercialization. The paper ends with a discussion on a number of cable-ring variants suitable for challenging new steerable designs in the future.
Shape-Memory Nitinol Tympanostomy Tube and All-in-One Introducer Device for Treatment of Otitis Media
Authors: Loushin Michael , Leland Keith
Published: August 2010

Otitis media is the most common bacterial illness in children, resulting in millions of office visits, antibiotic prescriptions, and surgical procedures annually in the United States. Antibiotics are commonly prescribed and has resulted in increased prevalence of antibiotic resistant strains of organisms. Additionally, patients with otitis media are candidates for tympanocentesis, myringotomy, and tympanostomy tube placement procedures. The ability to safely and efficiently perform these procedures to accurately diagnose, identify the bacterial organism, and treat otitis media with point of care therapy is needed. A shape-memory nitinol tympanostomy tube and an all-in-one introducer device (OtoStent tympanostomy device) currently under development will allow clinicians to safely and efficiently perform myringotomy, tympanocentesis, and tympanostomy tube placement with a single disposable device.
A New Actuation System With Simulated Electrocardiogram Signal for MR Elastography
Authors: Chui Cheekong
Published: August 2010

Elasticity is an important physical attribute of biological tissue. Elasticity of normal tissue can differ significantly with pathological tissue in its stiffness. It is important to develop a clinical viable method to determine and visualize the elasticity of histological tissue. Magnetic resonance (MR) elastography is a promising noninvasive method to quantitatively measure the viscoelastic properties of biological tissue. We developed a new quasi-static actuation system with the spatial modulation of magnetization (SPAMM) imaging pulse sequence. The MR compatible actuation system consists of an ultrasonic motor, a force sensor, motion-transmission mechanism, ECG signal generation, and controller. The high torque ultrasonic motor, USR60-E3 by Shinsei Corporation, Japan, can function well in the magnetic environment. The simulated ECG signal is generated using function generator, and outputted to both MR scanner and controller respectively. SPAMM imaging sequence is utilized to acquire tagging images of the deformed tissue. The actuation is synchronized with the SPAMM sequence via simulated ECG signal. Indentation force is measured by MR compatible force sensor for the subsequent stiffness inversion procedure. Imaging experiments were conducted using this actuation system and a GE SIGNA 1.5T MR scanner. Clear tag-deformed images of agar gel phantom have been acquired. The results demonstrated the feasibility of utilizing SPAMM sequence and the proposed actuation system for tissue characterization. In comparison with dynamic method of MR elastography, this quasi-static method is relatively simple to implement since no motion sensitive gradient or gradient synchronization is required. A limitation of indentation method is the difficulty to obtain significant deformation of tumor inside the liver organ. Since radio frequency (RF) needle is inserted into liver organ during tumor ablation, the proposed system with needle-based actuation making use of this inevitable insertion will be able to intra-operatively image the liver tumor during ablation. The RF needle can directly vibrate the pathological tissue within the liver organ.
Irregular Bone Defect Detection and Device on Dental Implants
Authors: Zhuang H.-B. , Pan Min-Chun
Published: August 2010

Dental implants are generally used in edentulous patients. The key issue of this dental surgery is the effective osseointegration of implants with spongy bone and cortical bone and then they become a part of loading structure. Current osseointegration detection devices only offer overall evaluation without the information of location and orientation of bone defects. This study is to develop detection techniques to measure the quantity as well as to locate the orientation of imperfection around bone-implant interface based on resonance frequency analysis (RFA). A noncontact measurement technique is performed with acoustic excitation through a loud-speaker and displacement response via a capacity-type pick-up. In the first and second series experiments, RFA is applied to estimate the orientation and quantity of irregular bone defects on various in-vitro faulty models. The variation in RF not only locates the orientation and depth of defects but also reflects the change of boundary conditions surrounding the defective models. According to these results, the detection technique to locate irregular osseointegration is established. Furthermore, the detection device to this end is proposed as well. The proposed examining approach and device are promising and able to assist dentists in dental implant surgery.
Automatic Oxygen Delivery System for Premature Babies
Authors: Do Thao P. , Eubank Lindsey J. , Coulter Devin S. , Freihaut John M. , Guevara Carlos E. , Wicks Alfred , Muelenaer Andre A.
Published: August 2010

When an infant is born prematurely, there are a number of health risks. Among these are underdeveloped lungs, which can lead to abnormal gas exchange of oxygen or hypoxemia. Hypoxemia is treated through oxygen therapy, which involves the delivery of supplemental oxygen to the patient but there are risks associated with this method. Risks include retinopathy, which can cause eye damage when oxygen concentration is too high, and brain damage, when the concentration is too low [1]. Supplemental oxygen concentration must be controlled rigorously. Currently healthcare staff monitors infants’ blood oxygen saturation level using a pulse oximeter. They manually adjust the oxygen concentration using an air-oxygen blender. Inconsistent manual adjustments can produce excessive fluctuations and cause the actual oxygen saturation level to deviate from the target value. Precision and accuracy are compromised. This project develops an automatic oxygen delivery system that regulates the supplemental oxygen concentration to obtain a target blood oxygen saturation level. A microprocessor uses a LABVIEW® program to analyze pulse oximeter and analyzer readings and control electronic valves in a redesigned air-oxygen blender. A user panel receives a target saturation level, displays patient data, and signals alarms when necessary. The prototype construction and testing began February 2010.
An Improved Smart Ankle Foot Othosis Design Using Dual Fluid Power Cylinders
Authors: Mehta Ricky , Rohrs Eric L. , Lipat Katarina F. , Reed Evan C. , Paliwal Manish
Published: August 2010

To design a smart ankle-foot orthosis (SAFO) that improves upon current ankle-foot orthoses used to treat steppage gait. Current ankle-foot orthoses are subjected to significant stresses on the ankle region of the structure, causing discomfort and the possible failure of the AFO. Although these AFOs have a constant stiffness, they do not reduce the occurrence of slap foot, where the foot slaps on the ground rather than gradually lowering it. The SAFO is an active ankle-foot orthosis that allows the user’s foot to follow a normal gait cycle. It is designed to reduce stress at the ankle by allowing for movement of the foot beyond a 90 deg angle for plantarflexion. The hinged ankle-foot orthosis is incorporated with a novel dual hydraulic-cylinder system, two tension springs, and force sensitive resistors. The force sensors are placed at the hallux, first metatarsal head, fifth metatarsal base, and heel. The foot movement actuation follows the force applied to the plantar surface of the foot during gait. The sensor outputs are fed to a signal processor and control interface to coordinate the motor actuation with the forces exerted by the user. The motor turns the screw attached to the hydraulic cylinders, which, thereby, control the orifice size by moving a plate in the cylinder, thus, changing the resistance. The cylinder filled with air will be pressurized during the lean phase, as the orifices will be closed and will provide power just as a spring would during the heel-off phase. After the heel strike, the resistance of the fluid-filled cylinder is decreased to slowly lower the foot. Once the foot is flat, the resistance of the fluid-filled cylinder is increased to keep the foot in a position to allow for toe clearance. During the heel-off event, the air-filled cylinder will assist the user with the power to push off. When toe-off occurs, the fluid-filled cylinder will decrease the resistance to allow the tension springs to bring the foot back to neutral position. To power the motor and sensors, a rechargeable battery pack is placed in a waist bag. The SAFO’s flexible design uses a novel combination of hydraulic-pneumatic cylinders to prevent foot drop, and restore the user’s sense of normalcy by providing late stance plantarflexion and a return to neutral position in early swing phase.
Exo-Leg: An Active Single-Leg External Walking Assist Device
Authors: Coughlin Thomas , Knight Jessica L. , Hinkle Alex , Van Cleve Matt , Al-Omaishi Salam , Paliwal Manish
Published: August 2010

Lower extremity weakness is a serious problem afflicting people all over the world. Until recently, the mobility options for people with this condition have been confining and limit the individual’s functionality. Walking assist devices are presently in development to restore hands-free walking to people with lower extremity weakness. These devices provide the necessary support and power to enable the individual to restore normal ambulation. The proposed design of exoleg, a single leg external walking assist device, addresses the demographic of people with lower extremity weakness. The design includes replication of the gait cycle utilizing mechanical links and user control interface with emphasis on safety. The design couples the actuation of the knee and hip through the use of linkages connected to a single motor. The actuation of the hip is controlled by a 4 bars crank-rocker linkage system while the knee is actuated by corresponding linkages (designed in WORKING MODEL 2D, a commercial simulation software) that generates the knee kinematic profile. The angular profiles of the knee and hip actuations are compared with the actual knee and hip angular trajectories. The frame of the device incorporates a passive ankle stabilization system to compensate for the effects of foot drop. The system utilizes feedback from trigger points from pressure sensors on the foot and goniometers at the hip and knee joints to measure the angulations in gait to keep the device in synchronization with natural ambulation. An on-board microprocessor receives the feedback from the trigger points and sends the actuation signal to the motor. A conceptual design of electrostatic actuator motor is also proposed to keep the device light weight and compact.
In-Vitro Tests of a Rapid, Stable-Temperature Recharging System for Implantable Batteries
Authors: Radziemski Leon , Denison Arthur , Dunn Floyd , Bell Steve , Cochran Eugene
Published: August 2010

In this paper, the authors report in-vitro tests of an ultrasound system and method of wirelessly transmitting significant amounts of energy into the human body for the purpose of recharging implantable batteries. We demonstrate the complete charging of Li-ion batteries with energy capacities of 35 mA h, 200 mA h, and 600 mA h through several types of animal tissue while keeping the temperature rise of the tissue and piezoelectric receiver below the desired 2°C human safety limit recommended by FDA medical device guidelines. Given these encouraging results, it is logical to conclude that the rapidly growing neurostimulator market is a desirable and appropriate target for introduction of this novel recharging method.
Active Management of Healthcare Operations: A Dynamic System View of Healthcare Delivery
Authors: Moen Dennis , Meredith Lynn
Published: August 2010

The migration to modern information systems and advancement in noninvasive health monitoring devices enable highly mobile users to support increased efficiencies and improvements in delivery of healthcare. Users of these systems are likely to have different needs or views of information either because of organizational role or because of geographic location. In this distributed architecture, available resources must dynamically be able to be reassigned to respond to external factors such as changes in the environment, changes in short-term objectives, reallocation of responsibilities, and changes in resource consumption patterns. This paper describes a framework for healthcare decision making and management of healthcare operations through the application of dynamic resource management using information technology for what we call active management of healthcare operations.
Enhancing Video Capsule Endoscopy: Location and Bleeding Detection
Authors: Inoue Yurika , Sarvestani Amir Sabet , Yap Jonathan , Yeung Douglas L.
Published: August 2010

Video capsule endoscopy (VCE) is a method used to wirelessly scan the gastrointestinal (GI) tract lumen. Despite the effectiveness of VCE in GI endoscopic procedures, VCE is limited because it lacks the capability to exactly locate itself as well as accurately detect bleeding or clotting within the GI tract. The unreliability of localization combined with inaccurate blood detection in VCE ultimately leads to wired endoscopy for additional diagnosis. In this paper, a method to address localization of the VCE device, also known as a pill camera or capsule, in conjunction with an accurate detection of active bleeding and clotting inside the small intestine, is introduced. The Texas Instruments, ZigBee® kit, which uses a 3D trilateration method will be used for accurate location detection and image transmission throughout the VCE procedure. The system will be interfaced with software providing end users with the path and total distance traveled by the pill capsule within the small intestine. The blood detection system is enhanced by using a minilow energy wireless Raman spectrometry to scan for active bleeding or clots along the small intestinal wall. The employed spectrometry method scans for wavelengths based on blood’s optical characteristics and records any image fitting the exact spectrum. Blood detection and localization data are coupled together and then transferred to an external receiver. These two improvements together will enhance capsule endoscopy procedures and fill the gap created by the existing capsule endoscopy technologies, therefore, meeting the needs of physicians and patients.
Design of a Compliant Steerable Arthroscopic Punch
Authors: Nai Tin Y. , Tuijthof Gabrielle J. M. , Herder Just
Published: August 2010

Meniscectomy is a medical procedure where ruptured meniscal tissue is removed within the knee joint. The conventional cutters fail to reach the entire meniscus. Therefore, the focus of this study is to create a steerable joint, which allows sideway steering of the tip to increase the reachability within the knee joint. Additionally, the steerable joint is required to be robust to transmit a cutting force of up to 190 N. The mechanism design is divided into the functions: steering and actuating cutting mechanism. The most promising solution of these functions was combined and resulted in the use of a crossed configuration of a compliant rolling-contact element for the instrument joint. Flexural steering beams actuate the rotation of the joint using the principle of a parallelogram mechanism. The prototype has a range of motion of +25 deg and −22 deg with a steering stiffness at the handle side of 33 N mm/rad. An axial load of 200 N on the tip corresponded with a parasitic deflection of 4 deg. This unique type of steerable instrument shows potential to be functional in meniscectomy due to the great robustness of the joint.
Hydraulic Remotely Adjustable Pulmonary Artery Banding
Authors: Dal Pozzo Davide , Deterre Martin , Eggenspieler Damien , Lobovsky Maxim , Pigula Frank , Slocum Alexander H.
Published: August 2010

Each year approximately 2000 children are born with a form of congenital heart disease that would benefit from mechanical restriction, or banding, of the pulmonary artery. [1,2] Installing or changing the setup of the banding requires an open chest surgery and during the first 6 months of the patient’s life, physiological parameters evolve rapidly, resulting in need for frequent reoperations. Mortality for those treated patients may be as high as 10–20%. [3] While many devices have been patented, none of them have been adopted due to size, adjustability, or reliability constraints with regard to implantation in newborns, especially below 6 months of age. Here we present the conception, design, and scale model testing of a novel pulmonary banding system for infants. This system features a hydraulic mechanical stepper actuator that offers great advantages in both reliability and compactness. As a proof of concept, we built a 5:1 scale working prototype that demonstrated the desired functionality of the device. Further steps involve scaling down the device so first porcine trials can be started.
Stiffness Compensation in Hand Prostheses With Cosmetic Coverings Using Statically Balanced Mechanisms
Authors: Tolou Nima , Smit Gerwin , Nikooyan Ali Asadi , Plettenburg Dick , Herder Just
Published: August 2010

Although hand prostheses with a cosmetic covering are commercially available for disabled people, the operating effort due to the stiffness of the mechanism is high. This results in high power requirements. This paper aims to present a new concept of mechanisms for the compensation of the nonlinear stiffness of hand prostheses by using statically balanced mechanisms with a nonlinear behavior. This concept was based on a combination of stability phases of snap-through buckling in bistable spring mechanisms to create the nonlinear balancing force. To demonstrate the efficiency of the concept, an optimized design for a case study of a child-sized hand prosthesis is also presented. A pattern search method was applied for the optimization. As a result, the calculated stiffness and, thereby, the operating effort was reduced by 96%. It can be concluded from the conceptual and numerical results that the presented concept provides a highly efficient solution to the discussed problem.
Predictive Modeling of Transplant-Related Mortality
Authors: Cai Feng
Published: August 2010

This paper describes the application of machine learning approaches for predictive modeling to improve the estimation of risks for complications of allogeneic hematopoietic cell transplantation (HCT) including relapse, graft-versus-host disease, and transplant-related mortality (TRM). Clinical disease and demographic factors known to impact the outcome of HCT include: recipient and donor age, type of donor (related/unrelated), donor-recipient gender, diagnosis and disease status pre-HCT, and stem cell source (peripheral blood, marrow, and umbilical cord blood). However, biostatistical analysis of risk has only limited accuracy in estimating a given patient’s risks of serous post-HCT complications. We describe the application of standard support vector machine (SVM) classifiers for data-analytic modeling of TRM. The goal is to predict the binary output TRM (alive or dead) from a set of genetic, demographic, and clinical inputs. Classification decision rule is estimated using SVM approach appropriate for such sparse multivariate data. This study compares several feature selection techniques for modeling TRM and objectively evaluates the quality of feature selection via prediction accuracy of the corresponding SVM classifiers. In addition, we discuss methods for interpretation of multivariate SVM models.
Breast Tumor Detection Instrument Through Mammography Based NIR DOT
Authors: Chen Jun-Yu , Jiang H.-Z. , Chen L.-Y. , Pan Min-Chun , Wu Ch.-T. , Pan Min-Cheng
Published: August 2010

X-ray mammography has been used in the early detection of breast tumors for decades. Related techniques to enhance preventive screenings are still demanding. Since the 1990s, near infrared diffuse optical tomography (NIR DOT), a functional medical imaging modality, is being exploited and developed to reconstruct optical-coefficient images of tissues. Much endeavor to improve the spatial resolution and contrast of DOT images has been exerted for clinic applications in the diagnosis of breast tumors. The study aims at the design, implementation, and verification of a mammography based NIR DOT. This multimodality imaging method is able to provide information that neither X-ray nor diffuse optical tomography can give alone. To this end, a device with multiple-channel switching of NIR sources and translational scanning of out-emitted intensity constructed on a commercialized mammography system is being designed and built up. We employ the mammography image as structure information that is used as an initial guess for the image reconstruction of optical properties of tissues. Preliminary numerical trials are performed using heterogeneous phantoms made of high-scattering Intralipid. Promising results are obtained with various spatial resolutions due to partial NIR detected intensity.
Designing Medical Devices for the Developing World: Best Practices and Hands-on Approaches in D-Lab Health
Authors: Srivastava Amit , Jain Priyanka , Liang Shichao , Lin Allen , Ravel Deepali , Wang Yi , Gomez-Marquez Jose
Published: August 2010

The design of medical technologies for developing countries is a multidisciplinary process. We describe a model process for an appropriate medical device design. D-Lab Health combines real world projects and partners with a diverse student team to provide experiential educational opportunities in a developing country health care setting; in turn, the partners benefit from student medical device designs. In order to effectively communicate practical design strategies toward an appropriate design for medical technology, a series of accelerated technology learning modules was developed using commercially available and customized medical devices. Each module included a formal framework for the students to think about the competing priorities of the user, chooser, payer, and approver of such global health technologies, christened the “global health innovation compass.” These modules provided a hands-on laboratory experience that demystified the design process. This was particularly useful for nonengineering students who were able to add value to the project through their life-sciences background. An essential component of the course was a week-long visit to our field partners in Nicaragua to enable the students to get first hand experience and to identify a health need they could address with a technology solution. Subsequently, the students utilized their hands-on training to develop medical device prototypes within an abbreviated production schedule of 3 weeks. We describe the design process for one such prototype “a low cost glucometer.”
A Device and Methodology for Continuous Hypothermic Perfusion of Explanted Large Mammalian Hearts, Followed by In Vitro Langendorff Reanimation: Pilot Studies
Authors: Brusen Robin M. , Rolfes Christopher D. , Howard Stephen A. , Bateman Michael G. , Iaizzo Paul A.
Published: August 2010

The current methodologies of clinical heart transplantation limit the ischemic window to 4–6 h. Periods longer than this can induce dysfunction in the organ and can lead to increased patient morbidity and mortality. An alternative to the current methods of static cold storage (CS) is continuous hypothermic perfusion (CHP), where a hypothermic oxygenated crystalloid solution is mechanically perfused through the coronary arteries. This has been shown to preserve the function for up to 72 h, but the techniques have yet to be optimized. We have developed an apparatus and methodology for performing CHP on large mammalian hearts, followed by reanimation in our in vitro Langendorff apparatus (The Visible HeartTM). We are also investigating the utility of the cardioprotective agents docosahexaenoic acid and [D-Ala2, D-Leu5] enkephalin, both of which have shown cardioprotective effects in our laboratory, and we believe that their addition to the preservation solution can further extend the transplant window. A series of pilot studies has been performed to date, with modestly successful results. Hearts preserved with CHP seem to show better functionality than CS hearts but far worse functionality than hearts reanimated immediately after explant. We hope to use this system to optimize CHP methodology and eventually develop a system for prolonging the window for heart transplantation.
Artificial Neural Network Analysis of Heart Sounds Captured From an Acoustic Stethoscope and Emailed Using iStethoscopePro
Authors: Palm Dustin , Burns Stan , Pasupathy Trichy , Deip Eric , Blair Brittney , Flynn Misty , Drewek Amanda , Sjostrand Matt , Stephenson Brian , Nordehn Glenn
Published: August 2010

Valvular heart disease is a significant problem. The primary care physician initially does assessment through auscultation. Accuracy in classification of sounds is suboptimal (20–40%). Technological advances have paralleled an increase in referral for Doppler echocardiography and a decrease in auscultatory skill. An increase in the referral of functionally innocent heart murmurs has contributed to the increasing cost of care. A computer-aided analysis has been shown to improve the accuracy of primary care physicians. A remote centralized computer-aided analysis could provide physicians with an additional tool in the assessment of heart murmurs, especially in settings without access to echocardiography. iStethoscopePro is an application for the iPhone and iPod Touch capable of recording and emailing sounds. We developed a device, which interfaces with iStethoscopePro and any acoustic stethoscope. We used this device to capture heart sounds from a conventional acoustic stethoscope and email them using iStethoscopePro for analysis with an artificial neural network (ANN). Hypothesis: It is possible to record heart sounds from an acoustic stethoscope, email them, and classify them with an ANN. Our device recorded heart sounds with insignificant intersample variation. After training the ANN with representations of four heart murmurs (aortic regurgitation, aortic stenosis, mitral regurgitation, and mitral stenosis) and normal, we achieved an overall accuracy of 45% with sensitivities of 50–75%. A remote centralized analysis of sound captured from an acoustic stethoscope is possible and could augment traditional auscultatory exams by offering an objective classification. Improving the accuracy and specificity of the ANN is necessary. This collection modality offers a method for the collection of a great deal of sounds for further development of artificial intelligence systems.
Emergency Cardiac Anterolateral Thoracotomy Simulator
Authors: Shahid Wajiha , Rybak Ofra , Rollins Josh , Schiffer Carly , Sienko Kathleen H. , Andreatta Pamela
Published: August 2010

Trauma is the leading cause of death in persons younger than 44 years old in America; half of the deaths occur within the first hour following the incident. The likelihood of survival for such critical trauma patients is significantly increased if an Emergency Department Thoracotomy (EDT) is performed. EDT entails the surgeon performing large and rapid incisions into the pleural space of the thoracic cavity to resuscitate patients who have suffered penetrating chest trauma. This procedure is highly invasive and rare and is typically conducted outside the operating theater in the absence of a trained cardiothoracic surgeon. Since most emergency clinicians are not trained to perform EDT and are often hesitant to perform it, poor outcomes are common. The use of clinical simulators offers the potential to eliminate these concerns; however, current medical simulators are not dedicated to the training of EDT. The goal of this work was to design and build a mechanical simulator to mimic the functionality of the rib cage and the components within the thoracic cavity to serve as a learning and assessment tool for conducting EDT. This design paper presents the user requirements and engineering specifications for the simulator, explains the materials selection approach employed for the thoracic components, and describes the iterative approach for designing, fabricating, and validating the EDT simulator.
Linear Control of Neuronal Spike Timing Using Phase Response Curves
Authors: Stigen Tyler , Danzl P. , Moehlis J , Netoff T. I.
Published: August 2010

We propose a simple, robust, and linear method to control the spike timing of a periodically firing neuron. The control scheme uses the neuron’s phase response curve to identify an area of optimal sensitivity for the chosen stimulation parameters. The spike advance as a function of current pulse amplitude is characterized at the optimal phase, and a linear least-squares regression is fit to the data. The inverted regression is used as the control function for this method. The efficacy of this method is demonstrated through numerical simulations of a Hodgkin–Huxley style neuron model as well as in real neurons from rat hippocampal slice preparations. The study shows a proof of concept for the application of a linear control scheme to control neuron spike timing in vitro. This study was done on an individual cell level, but translation to a tissue or network level is possible. Control schemes of this type could be implemented in a closed loop implantable device to treat neuromotor disorders involving pathologically neuronal activity such as epilepsy or Parkinson’s disease.
A Manual Insertion Mechanism for Percutaneous Cochlear Implantation
Authors: Schurzig Daniel , Smith Zachariah W. , Rucker D. Caleb , Labadie Robert F. , Webster Robert J.
Published: August 2010

Percutaneous cochlear implantation (PCI) is a recently developed minimally invasive technique that utilizes image guidance and a custom-made microstereotactic frame to guide a drill directly to the cochlea. It enables cochlear access through a single drill port, reducing invasiveness in comparison to mastoidectomy. With the reduction in invasiveness, PCI enables a corresponding reduction in visualization and space in which to work at the cochlear entry point. This precludes standard cochlear implant deployment techniques and necessitates a new insertion tool that can deploy a cochlear implant into the cochlea while working down a deep, narrow channel. In this paper, we describe a manual insertion tool that we have developed for this purpose. The tool is capable of inserting an electrode array into the cochlea using the advance off-stylet technique, using simple manual controls on its handle.
Optimal Sensor Design Using Patient-Specific Images
Authors: Basati Sukhi , Harris Timothy J. , Linninger Andreas A.
Published: August 2010

In diseases such as hydrocephalus, the cerebral ventricles enlarge. The treatment options for these patients are presently based on pressure, which has limited capabilities. We present the design of a volume sensor as an alternative monitoring option. Through the use of computer aided design and simulation, we optimized a sensor in silico with fewer resources. Specifically, we designed a sensor for animal experimentation with a scalable procedure for human sensors. In this paper, we present a rational design approach for a sensor that integrates advances in medical imaging. Magnetic resonance data sets of both normal and diseased subjects were used as a virtual laboratory. Finite element simulations were performed under pathological disease states of the brain as a contribution toward an accelerated device design. An optimized sensor was then fabricated for these subjects based on the outcome of the simulations. In this paper, we explain how a computer aided subject-specific design was used to help fabricate and test our sensor.
Statistical Shape Modeling of Femurs Using Morphing and Principal Component Analysis
Authors: Hraiech Najah , Boichon Christelle , Rochette Michel , Marchal Thierry , Horner Marc
Published: August 2010

In this paper, we describe a method for automatically building a statistical shape model by applying a morphing method and a principal component analysis (PCA) to a large database of femurs. One of the major challenges in building a shape model from a training data set of 3D objects is the determination of the correspondence between different shapes. In our work, we solve this problem by using a morphing method. The morphing method consists of deforming the same template mesh over a large database of femur geometries, which results in isotopological meshes and one to one correspondences; i.e., the resulting meshes have the same number of nodes, the same number of elements, and the same connectivity in all morphed meshes. By applying the morphing-based registration followed by PCA to a large database of femurs, we demonstrate that the method can be used to derive a low dimensional representation of the main variabilities of the femur geometry.
Numerical and Experimental Simulations as Symbiotic Tools for Solving Complex Biothermal Problems
Authors: Sparrow Ephraim , Abraham John , Bayazit Yilmaz , Lovik Ryan , Smith Dianna
Published: August 2010

In the design of medical devices, the use of numerical simulation, either with or without complementary experimentation, may lead to a more competent product. The experimentation in question may either be performed in vitro or in vivo. This paper conveys a case study in which the two methodologies, numerical simulation and in vitro experimentation used in tandem, enabled the evaluation of safety issues related to a heat-generating implant. The numerical simulation was implemented by means of ANSYS finite-element software employed in the transient mode. The experimental work provided information necessary for the execution of the simulation and, therefore, was performed as the first phase of the research. The implant is of the type that is equipped with a short-lived battery that requires intermittent recharging. The recharging is accomplished by means of an antenna that is externally mounted on the skin surface. The antenna is the primary of a transformer, and the implant contains the secondary of the transformer. During the recharging period of the battery, heat is generated in both the antenna and the implant. By the symbiotic use of the experimental results and the numerical simulation, time-dependent temperatures were determined in the tissue that is situated in the neighborhood of the implant and the antenna. These temperatures were evaluated from the standpoint of possible tissue damage.