An MD&DI August 1999 Column
Twelve companies recognized for outstanding achievements in medical device development received gold awards during the presentation ceremony for the Medical Design Excellence Awards of 1999.
This year's Medical Design Excellence Awards again underscore the unique nature of medical device development. Each device recognized for its design excellence was the fulfillment of a vision. Many resulted from the focused efforts of design teams that had been formed specifically to meet a carefully defined technical challenge. Other products were developed by persistent individuals who were struck by sudden inspiration or who looked at conventional technology from a new perspective and saw the potential to make a significant improvement.
It is clear that the need for improved or new medical products continually drives the pursuit of innovation in novel device designs and advanced manufacturing technologies. The emergence of new clinical applications and the availability of new technologies also spark the development of new medical products. These processes, however, are seldom bound by any rigid timetable. Most often, the process is long and arduous, involving years filled with numerous redesigns and prototypes, as well as continuous product and market testing. In rare instances, when all factors are in perfect accord, an innovation will burst quickly onto the marketsometimes within months.
This is the remarkable nature of the process of invention and innovation that leads ultimately to the introduction of new or advanced medical devices. The development of new products clearly requires a knowledge of the general process of technological improvement and an awareness of the many generations of incremental changes that often make predicting a device's ultimate use and design so difficult. Developers must recognize the value of product feedback rendered by users in real-life settings and of the critical role played by entrepreneurs and small companies in the creation of some of the most innovative products. They also must remain aware that the ability to correctly assess future trends and needs is of the utmost importance in the development of products that will succeed in the marketplace.
In developing new devices, designers must also strike a precarious balance between form and function. Does the device perform the tasks necessary to provide the desired medical treatment? Does it offer any advantages over conventional methods? Is use of the product cost-effective? Is the device simple to operate and easy to learn? Will it be readily accepted by end-users?
Form and function, cost-effectiveness, user acceptance, ease of use, and simplicity of training were among the factors considered by this year's panel of eight MDEA judges. The following 1999 gold-award winners were selected for having achieved excellence in their pursuit of innovation and invention.
THE On3: ENABLING HEALTHCARE WORKERS TO MOVE A PATIENTWITHOUT BECOMING ONE
According to the U.S. Department of Labor, each year 56% of all healthcare workers injure their backs on the job, and back injuries account for up to 80% of total injury costs among this group. Thomas W. Votel, MD, inventor of the On3 lateral transfer device, had witnessed his fair share of back injuries when he decided to design a system that would remedy the situation. "We developed an easy-to-use device that allows one person to do what it used to take six to do. And, better yet, it reduces the risk of a back injury to a respectable levellike zero," the inventor explains.
The On3 allows a single healthcare worker to move a patient by wrapping the patient's draw sheet around the On3's transfer rod, clamping a belt to the rod, and clicking a retract-able, handheld control. The device smoothly transfers the patient from bed to cart in about 20 seconds.
From his initial concept for a one-person transfer device, Votel developed a crude mock-up. Because the common denominator between a hospital bed and a cart is the bed rail, he decided to use a mechanism attached to the bed rail to pull the patient. He took the hand crank off his tennis court net and fashioned it into a 25-lb unit that attached to the bed rail, yet was strong enough to pull a patient when a caregiver simply turned the crank.
At this point, Ergodyne (St. Paul, MN), distributor and manufacturer of the On3, approached redgroup (Minneapolis) to oversee R&D for the device, says the inventor's son, Thomas F. Votel, Ergodyne president and CEO. When the design team took this early, nonfunctional concept to three Minnesota hospitals for validation, the staff members told them they would not want to pick up and carry a device that heavy, and that they had no place to store it. They suggested the design team mount the device on a rolling cart, a commonly accepted way to transport heavy equipment in hospitals.
The R&D program soon changed dramatically, says Lars Runquist, a principal with redgroup. "Real estate is scarce in hospitals. The pushcart idea allowed the device to be moved easily and stored conveniently, even in hallways."
Reliability and strength were other important factors in the On3's design. "We needed a unit that could safely transfer a 500-lb patient, and that would last for years and be reliable to the end-user. If they (healthcare workers) didn't trust the machine, they wouldn't use it on a daily basis," Runquist explains. Extensive life and strength testing of the product were conducted at redgroup to ensure heavy-lifting capability and durability.
"Once we had a workable prototype, we tested it in about half a dozen hospitals," Votel says. In particular, Ergodyne hired the market research firm Marquette Research (Minneapolis) to conduct focus groups at two area hospitals. "We wanted to capture the end-user response to the device before we started the manufacturing process," he says. The focus groups were asked to fill out sophisticated questionnaires and were interviewed extensively for their input.
This research helped designers fine-tune the product's appearance as well as function. "We didn't want a heavy-duty industrial look, like a winch, but one that was simple and accessible, not only for the hospital workers, but also something that looked comforting to the patient," Runquist emphasizes.
"From an interface standpoint, we kept it very simple," Runquist says. "It's battery operated, and the transfer rod folds in half to fit right in the unit for storage. Also, while standing on one side of the bed, the operator can adjust [bed] height with foot pedals, align the patient, and begin transferring by clicking the remote control without walking around the bed several times. Even the remote control has just two buttons, one to adjust for skew [if the patient is off-center] and one to begin transfer."
The name also reflects the device's accessible nature. "We didn't want a name like XJ-2000. The name needed to convey how simple this product is to use," Runquist says. On3 is a reference to a physician's directive to move a patient on the count of three, Runquist explains.
Overall, Runquist thinks the feedback from end-users was the most crucial decision-making tool in the design process. "The users dictated where things should go as opposed to the client," he explains. "We got their input, and every milestone was validated by the hospital staff. The end result exceeded their expectations."
THE ORAL-B CROSSACTION: A NEW ANGLE ON THE TOOTHBRUSH
In April 1996, Brad Baker assembled Team Discovery at Oral-B Laboratories (Belmont, CA). Its mission: to develop a breakthrough producta toothbrush that could clean teeth more effectively while offering an innovative ergonomic design. After three years of R&D, 26 patent filings, and a $70 million investment in new manufacturing processes, Oral-B has succeeded by delivering the most thoroughly researched product in its history: the CrossAction toothbrush.
One of the first challenges after assembling the design team was to rapidly develop prototypes, Baker explains. "Generally, it takes four to six months from the time we have an idea for a brush to when we can try it out on a consumer," Baker says. "With our dedicated focus on the product (the CrossAction) and a clear objective, we were able to reduce that to five weeks." Ultimately, consumers tested and gave feedback on more than 50 prototypes Team Discovery had designed based on the consumers' input.
Data were obtained from 72 tests involving more than 4000 consumers to determine desirable features, including a head that is tapered to reach back teeth, bristles that can reach around back teeth, high and low bristles to fit tooth shapes and crevices, and a rubber handle for a better grip. Experts then observed brushing and gripping behavior both in laboratory settings and in consumers' homes. Using the data, ergonomists, kinesiologists, and design research experts defined optimal cross sections for the toothbrush bristles, center of gravity location, elastomeric grip zones, and handle-head geometry. The bristles are also microtextured, making the entire bristlenot just the tipsmore effective. Blue indicator bristles fade when it's time to replace the brush. Drawing on the expertise of a diversified design team was vital to the product's success, Baker says.
One of the CrossAction's most innovative features is the CrissCross bristle design. High-speed video cameras and computer imaging analysis of people brushing their teeth revealed that bristles are most effective the moment the brush changes direction because that's when they are angled enough to penetrate between teeth. The CrissCross bristles fill the space between the teeth longer than standard vertical bristles. After spending more than $2 million on independent clinical studies, the company determined that the bristle design removes 25% more plaque than today's top-selling toothbrush.
A second notable innovation is the brush's handle design. Research revealed five basic toothbrush grips: precision, power, spoon, oblique, and, the most common, the distal oblique. The CrossAction handle addresses all five grips and various hand sizes by using a unique combination of flat and curved surfaces, and rubber gripping areas.
THE HEMATYPE SEGMENT DEVICE: ENSURING USER SAFETY
Protecting blood samplesand healthcare workersfrom contamination, especially in the age of HIV, is a serious problem in blood banks and hospital laboratories where lab technicians routinely draw samples for typing and cross-matching. Typically, a technician obtains a sample by cutting a flexible segment of tubing filled with blood with scissors, then squeezing the sample into a glass test tube. This results in a number of problems, such as blood spraying onto the healthcare worker or work surfaces, sharps injuries from cleaning scissors between cuttings, and the improper cleaning of scissors blades between cuttings, resulting in cross-contamination.
To address this problem, there is the Hematype, a small, disposable plastic device designed to eliminate virtually all problems associated with scissors. The Hematype houses a tiny steel needle that never comes in contact with the healthcare worker's skin. To use the Hematype, a technician places it atop an upright empty test tube in a rack and pushes one end of a blood-filled tube into the device until it is pierced by the needle. The technician then gently squeezes the tube to obtain a blood sample. Because the tubing stays inside the device, once a few drops of blood have been squeezed into the test tube, the remaining sample and Hematype can be discarded in a biohazard medical waste container, reducing a worker's exposure to blood.
"There are other products that improve user safety, but to take it to the next level, we needed to minimize the breaking of the test tube and make a product that is intuitiveone you can understand just by looking at it," says Alan Wanderer, MD, medical director of Medical Safety Products Inc. (MSPI; Englewood, CO).
After a prototype was developed, MSPI conducted a clinical trial with several hospitals and one blood bank. Each facility was given the Hematype and several other devices and asked to compare features and performance. They were not told which product was being tested and were asked to choose the one they believed was the safest and easiest to use. Users' comments confirmed that the Hematype's inventors had created an easy-to-use solution.
To reduce test tube breakage, MSPI designed the Hematype so that its force is vertical and directed at the top, or rim, of the test tube, the strongest part. This design requires less downward vertical force to puncture the tubing segment than do other devices created for this purpose. Most such devices are situated inside the test tube and radial forces can cause the sides of the test tube to break when pressure is applied.
Another challenge in designing the Hematype was in accounting for different blood tubing manufacturers. Each brand of tubing has a slightly different thickness, width, and flexibility, and there are various methods of heat-sealing the segment ends. The Hematype accounts for all types of tubing. The inside of the device is ringed with alternating ribs and slots that are intended to help guide various-sized segments toward the needle.
Getting the healthcare community to accept new safety products can be difficult because of the intense cost-consciousness of most healthcare organizations, a reluctance to change procedures, and regulatory controls that hamper new product development, Wanderer notes. "Because [the Hematype] is disposable, the price was extremely important," he says. "We needed to be able to mass manufacture multimillion units cost-effectively. The mission was to be able to manufacture a product at a low enough cost that permitted acceptable pricing in a price-conscious market. This was accomplished using thoughtful design development both for the product and the multicavity tooling, cost-conscious materials selection, and efficient assembly techniques. The end result has been our ability to market a product at a reasonable price with an acceptable profit margin."
THE HI & DRI ISOLATOR: SIMPLIFYING DENTAL VISITS
The Hi & Dri, a 67-cent plastic oral isolation and protection device, keeps a patient's tongue and cheek out of harm's way while the dentist is at work. The Hi & Dri attaches to a piece of flexible tubing on the dental station's vacuum line, providing the dentist with access to the teeth while simultaneously protecting the patient's tongue and cheek from the drill and keeping the patient's mouth open. The vacuum suction keeps the patient's mouth clean and dry, removing saliva and aerosol mists from the dental drill and particulate material such as stray pieces of filling material. This single device replaces an arsenal of dental helpers including cotton rolls, saliva ejector tubes, tongue depressors, cheek retractorsand, sometimes, even the dental assistant. The device is so effective that it enables a dentist to perform most procedures single-handedly, freeing the dental assistant for other important tasks.
From its inception, the Hi & Dri was on the fast track. DriDent, the developer of the Hi & Dri system, initially approached the industrial designer Microplas Inc. (Clinton, MA) with a breadboard model of the device and with the desire to get molded parts to a dental show in October, which was only five months away.
One of the first issues for the design team to tackle was to determine the appropriate size and form for the device. Although DriDent wanted a shape that would work for 95% of the adult population, two sizes were eventually designed after the company was convinced that a "one size fits all" approach would not work. By using anatomical models and plaster castings of patients' mouths, a series of hand-fabricated models was created. The device shape also had to maximize the working area for the dentist. This meant keeping the material thickness and size of the vacuum chamber to a minimum. After experimenting with several shapes and sizes, a final form was selected and a functional model was created for testing.
"We came up with the concept and designed the best way to manufacture it first," says Steven Callahan, Microplas president. "Then we engineered the device and came up with the final aesthetic form." Pro/Engineer software was used to create the 3-D database that was created during the engineering process. "This would have been impossible with the old 2-D process," says Christopher Reinke, senior product designer at Microplas.
Determining the best and most cost-effective manufacturing process was the most significant factor in the design process, says Callahan. "The downstream people were involved the whole way," he adds. "The collaborative effort between design and manufacturing is the reason for this product's success. Manufacturing an amorphic form required a tricky processit's not easy to mold." Because of the tight cost restriction, and because the device had to be hollow and airtight to work with the vacuum line, a polypropylene injection molding process was eventually chosen to produce the final two-part design. A secondary ultrasonic welding operation is used to assemble the two halves. Multicavity tooling is being used along with semiautomated assembly equipment to achieve pricing goals and first-year volumes of 46 million units.
THE INTUITIVE SYSTEM: MAKING SURGERY EASIER FOR BOTH PHYSICIAN AND PATIENT
Until recently, cardiac patients had to choose between two types of surgery: traditional open surgery and minimally invasive surgery (MIS). Traditional open surgery allows surgeons direct access to the organs but requires a large incision and results in trauma and lengthy recovery times for the patient. MIS minimizes incisions and accelerates recovery time. Such procedures require surgeons to use awkward, long-handled instruments, however, and the surgeon's movements are guided in a counterintuitive way via a CRT monitor. The Intuitive Surgical System eliminates the problem, combining the natural hand movements of open surgery with the less-traumatic benefits of MIS.
A government-funded research project by SRI, a Menlo Park, CA, think tank, served as inspiration for the Intuitive system. SRI's research involved the development of robotic ambulances in which surgery could be performed on wounded soldiers on the battlefield. When the founders of Intuitive Surgical Inc. (Mountain View, CA) came across the project, they realized it held potential for a novel form of MIS and formed a partnership with SRI to use the project as a launching point. Intuitive Surgical made several iterations of the design, resulting in the first product developed by the company, which was a privately held start-up.
Intuitive Surgical also consulted with several local surgeons who used MIS, particularly those with extensive cardiac and endoscopic surgery experience. Based on suggestions from the surgeons, they took the project to the dry-lab stage and worked with animals.
Spearheading a revolutionary product was a daunting task, says Steve Holmes, senior mechanical engineer for Intuitive Surgical. "There was no precedent," he explains. "The details of how it would work mechanically were difficult, and the hardware and software were tricky, but most challenging was envisioning how this would fit into the operating-room environment." The current system is the fifth generation, he estimates. "This [device] has undergone radical revisions as we learned more and more about the surgeon's environment."
The Intuitive system consists of two primary components: the viewing and control console and the remote surgical arm. Surgeons perform procedures seated at a console while viewing a high-resolution 3-D image of the surgical field. Highly specialized visual technology simultaneously transfers the surgeon's exact hand movements to precise microsurgical movements at the operative site, which requires only a 1-cm incision. Pencil-sized instruments incorporating the company's EndoWrist technology function like tiny computer-enhanced mechanical wrists, mimicking the dexterity of a surgeon's hand.
To create an immersive environment akin to open surgery, Intuitive Surgical developed its own proprietary 3-D viewing display system, used advanced robotics, replicated surgical instruments in the console, and created the EndoWrist technology that enhances performance by motion scaling, eliminating hand tremor, and providing sensory feedback. Because the surgeon's movements are counterintuitive in most traditional MIS systemsmoving the hand to the left displays as rightward movement on the monitorthe firm addressed the problem by using a more straightforward viewing system.
Ergonomics was another challenge because the designers needed to strike a balance between the working position of a surgeon, who is usually standing up and looking down while operating, and the new position, in which the surgeon sits with arms at a 90° angle and looks at a monitor. Following numerous wood and foam model evaluations and clinical studies, the design team responded by moving some controls, such as camera movement, focus, and cauterizing, to a foot pedal. Hand instruments were modeled after actual instruments but were enlarged slightly, and a comfortable armrest was provided. The stereovision system was improved as well.
Integrating nine subsystems into the design while keeping it simple posed other problems. "We wanted everything to combine to make a surgeon feel that he's working in a minimally invasive environment," Holmes says. "We needed a coherent product that was not intimidatingthat surgeons would want to interact with." The design team also needed to keep costs down to make surgery with the Intuitive system competitive with an open-surgery procedure. The entire business model was developed with the goal of not increasing costs for a procedure. Several of the tools are "reposable," meaning they can be used multiple times before disposal, and the cosmetic covers over the console are cast urethane for cost savings. The system "opens up the possibility of doing almost any surgery in a minimally invasive environment," Holmes says.