ERGONOMIC ULTRASOUNDDEVICEMay 5, 2004BME301Department of Biomedical EngineeringUniversity of Wisconsin-MadisonTeam MembersYao Lu, Meghan Olson,Emily Putzer, Heather WaldeckClientMark Kliewer, M.DDepartment of Radiology, UW-HospitalAdvisorProfessor Naomi CheslerDepartment of Biomedical EngineeringAbstractEighty percent of sonographers suffer from musculoskeletal disorders. These occurrences are attributed to the combination of sustained pinching and pushing needed during some ultrasound procedures as well as applyinga force while the arm is in an unnatural position. In order to alleviate the need for the sonographer to apply a sustained force, we developed a design that can maintain a force for the duration of the procedure. The design consists of an arc attached over the echocardiogram bed connected to a transducer by an arm. Movement is possible via a slider over the arc, a balland socket joint, a hinge joint, and a joint where the transducer is attached 0which allows slight rotation. The sonographer is able to lock the arm in place to sustain a force and performs the detailed movements necessary.1Problem StatementDuring echocardiogram and biopsy procedures, sonographers must apply high levels of pushing force with an unnatural arm position while performing detailed movements. The combination of these factors increases the number of work-related injuries and many times prevents the sonographer from performing their jobs. Our goal is to develop an ergonomic design which will minimize the forces applied and thereby reduce injuries to sonographers.Background InformationUltrasound is a widely used technique for imaging the inner organs of the body using sound waves. An ultrasound transducer (Figure 1) is used by a specialized technician called a sonographer to probe the outer surface of a patient’s body and produce a relevant image of the inner organs. The tip of the transducer made with a piezoelectric material and is used to sensesound waves given off from the body structures and convert them to electricsignals so they can be made into an image. A gel must be used on the surface of the skin in order to propagate the sound waves, which do not travel through air. In addition to the transducer, a large console (made up ofa keyboard and viewing screen) is used in an ultrasound reading to compile and display the image, make various adjustments, and change settings.2Figure 1: An ultrasonic transducer [Murphey]There are many types of procedures performed by sonographers usingultrasound. Two of the most time-consuming and fatiguing procedures are biopsies and echocardiograms [Kliewer]. A biopsy is performed by a doctor,who inserts a needle in a patient’s body, aiming to take a sample of a tumor. The doctor guides the needle using the image created by the sonographer, which must be very exact to include the small dimensions of the needle and to accommodate for the precise nature of the procedure.Similar to a biopsy, an echocardiogram has duration of approximately 45 minutes and can be made difficult in large patients who have excess skinand tissue surrounding the heart. The procedure images the heart of a patient to identify problems in heart valves or the function of the heart muscles. The sonographer must apply a large amount of force to the transducer in order to penetrate the tissue and circumvent the ribs to create a good image. The patient lies on his/her side (Figure 2) while the sonographer first applies pressure on a certain position on the patient’s 3chest and then on a position on the patient’s side in an upward direction through a hole in the bed. The latter position is to take advantage of the factthat, due to gravity, the patient’s heart will be more superficial and easier toimage. [Kliewer]Figure 2: An echocardiogram [The Franklin Institute]These types of procedures, especially the echocardiogram, require thesonographer to apply large amounts of force for long periods of time, while still needing to make detailed movements. These factors lead to a high incidence of musculoskeletal injuries. In fact, 80% of sonographers suffer from an injury such as this, most commonly in the neck, shoulder and/or wrist [Murphy]. Studies show that these disorders arise primarily because of the force needed in certain procedures (See Figure 3). It can also be noted that the pinching motion needed in conjunction with the force may 4cause problems as well by having the stretched tendons rub across the carpal bones thus causing swelling of the tendons.Figure 3: Survey of sonographers – Tasks that aggravate musculoskeletalsymptoms (Mean scores on a 5 point scale) [Murphy]Some of the main musculoskeletal injuries affecting sonographers are carpal tunnel syndrome, tendonitis, and shoulder bursitis. [Chattanooga Website] The former occurs in a region of the wrist that forms a tunnel of ligaments and tendons. When these structures become overused, as can happen with the repetitive movements made by a sonographer, they becomeinflamed and cut off the nerve that runs from the arm to the hand through the “carpal tunnel.” Tendonitis develops when the tendons in the wrist or elbow (connecting muscle to bone) become inflamed. Bursitis arise when the bursa (fluid filled sacs located at the joints) is inflamed, putting pressureon the joints and causing discomfort. The symptoms of all three musculoskeletal disorders mentioned can include pain, numbness, swelling, 5or weakness [Chattanooga Website]. A visual description of carpal tunnel syndrome, tendonitis, and bursitis is shown in Figure 4. (a) (b)Figure 4: (a) Carpal Tunnel Syndrome [Everybody Health] (b) ShoulderBursitis and Tendonitis [Orthopaedics Northeast]Due to the prevalence of the aforementioned injuries, many companies and research groups have tried to improve the current design and ultrasound procedure, all with little improvement. Companies have designed more ergonomic transducers with grooves or varied shapes that accommodate a palmer grip [Chattanooga Website]. Also, groups have urged sonographers to use proper posture and to stretch occasionally. However, these improvements have not lowered the incidence of injury because they do not eliminate the most important contributing factor: force applied for an extended period of time with an unnaturally positioned arm. Currently, research groups are working on more handle re-designs in the hopes of alleviating sonographer injuries.6Client RequirementsThe client
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