Murray Lawn

Modeling of a stair-climbing wheelchair mechanism with high single-step capability

In the field of providing mobility for the elderly and disabled, the aspect of dealing with stairs continues largely unresolved. This paper focuses on presenting the development of a stair-climbing wheelchair mechanism with high single-step capability. The mechanism is based on front and rear wheel clusters connected to the base (chair) via powered linkages so as to permit both autonomous stair ascent and descent in the forward direction, and high single-step functionality for such as direct entry to and from a van. Primary considerations were inherent stability, provision of a mechanism that is physically no larger than a standard powered wheelchair, aesthetics, and being based on readily available low-cost components.

Design of a robotic-hybrid wheelchair for operation in barrier present environments

The purpose of this paper is to outline a radical approach towards providing wheeled mobility to the elderly or disabled. A robotic-hybrid wheelchair designed for operation in barrier present environments (the real world) is currently under construction. The wheelchair is targeted towards providing increased independence for wheelchair users and/or much needed assistance to care workers in the field of facilitating mobility to those who cannot be independently mobile. The wheelchair incorporates a hybrid of 4 robotic legs resembling human legs in operation interfacing wheels. Each leg provides three degrees of freedom which are actuated hydraulically: two degrees for lift and one degree for dynamically variable track width. Each foot is further equipped with independently operated steering and drive motors. The resultant wheelchair is estimated to be capable of negotiating stairs and a single step of up to 70 cm to allow for direct boarding to a vehicle. The proposed control is via a radio control for operation by the user or assistant in the case of care worker assisted mobility. Key design aspects are safety, aesthetics and not exceeding the size of a standard powered wheelchair.

Development of a Tailored Thyroid Gland Phantom for Fine-Needle Aspiration Cytology by Three-Dimensional Printing

BACKGROUND Fine-needle aspiration cytology (FNAC) is a challenging and risky procedure for inexperienced clinicians to perform because of the proximity of the thyroid to the jugular veins, carotid arteries, and trachea. A phantom model for transfixion practice would help train clinicians in FNAC. OBJECTIVE To fabricate a tailored phantom with consideration for authenticity of size, touch, feel, and ultrasonographic (US) characteristics. METHODS A three-dimensional (3D) digital model of the human neck was reconstructed from computed tomography data of a subject. This model was used to create 3D-printed templates for various organs that require US visualization. The templates were injected with polymers that provided similar degrees of ultrasound permeability as the corresponding organs. For fabrication of each organ, the respective molds of organs, blood vessels, thyroid gland, and tumor were injected with the material. The fabricated components were then removed from the templates and colored. Individual components were then positioned in the neck mold, and agar gel was poured in. The complete phantom was then removed from the mold. Thereafter, 45 medical doctors and students performed ultrasound-guided FNAC using the phantom, following which they were queried regarding the value of the phantom. RESULTS The structure, US characteristics, and elasticity of the phantom were similar to those of the human subject. In the survey, all 45 participants replied that they found the phantom useful for FNAC training, and 30 medical students professed increased interest in thyroid diseases after using the phantom. CONCLUSIONS We successfully fabricated a tailored thyroid gland phantom for transfixion practice. As most of the phantom parts are injected in molds fabricated using a 3D printer, they can be easily reproduced once the molds are fabricated. This phantom is expected to serve as an effective and fully tailored training model for practicing thyroid gland transfixion.

Research on seamless development of surgical instruments based on biological mechanisms using CAD and 3D printer

In the area of manufacturing surgical instruments, the ability to rapidly design, prototype and test surgical instruments is critical. This paper provides a simple case study of the rapid development of two bio-mechanism based surgical instruments which are ergonomic, aesthetic and were successfully designed, prototyped and conceptually tested in a very short period of time.

DEVELOPMENT OF BALLOON-BASED ORGAN RETRACTOR FOR LAPAROSCOPIC SURGERY

Effective organ retraction is essential to ensure safe and efficient surgery, in the case of laparoscopic surgery, organ retraction is particularly difficult to achieve. Currently such as cherry dissectors are used for retraction, however the small size results in excessive stress on the organ being retracted. Therefore, we are developing a balloon-based retractor that provides similar functionality as the cherry dissector, particularly being able to pass through a small port, yet being expandable to provide a much greater contact area as well as improved traction, thus providing increased operating efficiency and improved safety in organ retraction. In this paper, the relative merits and demerits of a number of currently available retractors are compared. Parameters under consideration include shape, size, effective traction (coefficient of friction), type of actuation and ease of use. While parameters such as pressure distribution and effective traction have been objectively measured, other attributes u...

Face Mount Computer Input Device for Serious Disabled

For the human being, communication ability is essential for everyone. In the field of rehabilitation patients suffered by intractable diseases such as ALS(Amyotrophic Lateral Sclerosis) or Spine cord injury which can cause the damage of bodys nerve cell and further result in the loss of the many functions. In order to make the communication ability possible for patients, some input devices have been commercialized. But input devices for patients under bed-ridden condition need special consideration. Directions of the patient are changed every two hours for the prevention of the bedsore. Therefore, input device should be designed to cope with this situation. Readjustment od the sensor is unfavorable. In this paper two kind of input device are proposed. A feature of these prototyped device are mounted on the face with compact body.

Development of an actuation system for a rotary hydraulic brake on a low cost light weight knee-ankle-foot orthosis

In the field of rehabilitation following a stroke (Cerebral Apoplexy), having the patient walking as soon as possible is critical to recovery. Current practices rely heavily on the manual assistance of nursing staff to achieve this. To assist during this phase a low cost light weight single strut knee-ankle-foot orthosis (KAFO) has been developed. However the orthosis requires walking with the dysfunctional leg in a fixed straight stance resulting in the walking gait being difficult and unnatural. To achieve near natural gait walking a light weight hydraulically actuated rotary brake has been prototyped for this orthosis. This paper outlines a prototype actuation control system for this hydraulic brake during a walking gait. The controller uses a microcontroller provided with gyroscopic, angle, velocity and acceleration data and uses an algorithm to combine the data and actuate the rotary brake. The proposed controlled KAFO is low cost, light weight, low power and easy to setup.

Development of an effective training machine using muscle activity information

In the field of providing safe and effective equipment for physical training appropriate adjustment of loading levels for the targeted users is very important. Most training machines to date offer only fixed and coarse load adjustment. This paper details an advanced leg muscle training machine that has an intelligent load control system. The load control is provided by monitoring the users muscular condition by means of a muscle stiffness sensor as well as pressure being exerted on the machine. The loading can then be adapted continuously to optimally suit the users needs. The prototype demonstrated that the proposed machine has excellent load control abilities providing effective and safe training using dynamic load control and automatic restriction of loading levels based on the users muscle contraction levels

Balloon-Based Organ Retractor With Increased Safety and Reduced Invasiveness During Video-Assisted Thoracoscopic Surgery

Objectives. In recent years, video-assisted thoracoscopic surgery (VATS) has increasingly become the preferred technique for thoracic surgery. However, the inherent characteristics of the lungs as large, soft, slippery, and delicate creates difficulties for pulmonary surgery. In this article, we outline the development and assessment of a balloon-based organ retractor for VATS via collaboration between medical and engineering personnel. Methods. A dry lab trial and accompanying questionnaire assessment were performed by a group of thoracic surgeons. Objective pressure measurements were obtained, and animal experiment on pigs was performed. Results. In the dry lab trial, use of the developed organ retractor required significantly less time and resulted in fewer difficulties than using a Cherry Dissector. The measured pressure per mm2 of the developed retractor was clearly lower than that for the Cherry Dissector. The questionnaire completed by the surgeons following the dry lab and animal experiments showed that most of the surgeons (7 surgeons out of 9) were satisfied with the quality of the balloon-based retractor based on a score of 3.13 ± 0.28 (mean ± standard deviation) out of 4.0. During the animal experiment, the balloon-based retractor provided stable and clear viewing with minimal need for adjustment. Conclusion. This balloon-based retractor could contribute to increased safety and less-invasive VATS.

Sodium hydroxide based non-detergent decellularizing solution for rat lung

ABSTRACT Lung transplantation is the last option for the treatment of end stage chronic lung disorders. Because the shortage of donor lung organs represents the main hurdle, lung regeneration has been considered to overcome this hurdle. Recellularization of decellularized organ scaffold is a promising option for organ regeneration. Although detergents are ordinarily used for decellularization, other approaches are possible. Here we used high alkaline (pH12) sodium hydroxide (NaOH)-PBS solution without detergents for lung decellularization and compared the efficacy on DNA elimination and ECM preservation with detergent based decellularization solutions CHAPS and SDS. Immunohistochemical image analysis showed that cell components were removed by NaOH solution as well as other detergents. A Collagen and GAG assay showed that the collagen reduction of the NaOH group was comparable to that of the CHAPS and SDS groups. However, DNA reduction was more significant in the NaOH group than in other groups (p < 0.0001). The recellularization of HUVEC revealed cell attachment was not inferior to that of the SDS group. Ex vivo functional analysis showed 100% oxygen ventilation increased oxygen partial pressure as artificial hemoglobin vesicle-PBS solution passed through regenerated lungs in the SDS or NaOH group. It was concluded that the NaOH-PBS based decellularization solution was comparable to ordinal decellularizaton solutions and competitive in cost effectiveness and residues in the decellularized scaffold negligible, thus providing another potential option to detergent for future clinical usage.