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Designing Great Tech Products Since 1999

Discovering Customer Use Patterns & Designing for the Reality - A Case Study

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Overview
Baxter International, of McGaw Park, Illinois, released a new version of the
Jamshidi® Bone Marrow Biopsy needle in the mid 1990's.  Cardinal Health, of Dublin, Ohio, now owns the rights to produce the biopsy needle, which offers a significant level of improvement over previous versions of this type of clinical device.  "The Jamshidi (needle) has proved extremely popular for bone biopsy procedures over the past few years.  The T-Handle Jamshidi device has been designed to offer increased comfort to both operators and patients.  ...procedurally efficient, simple to use and fits comfortably in the hand.
...superior cortical penetration and medullary advancement that requires 25% less physical force."
- UK Medical, Ltd.


This version of the bone marrow biopsy needle system was conceived with goals of improving the procedure for both the user, who may be either a physician or technician, and the patient.  Improvements focused on making the procedure more comfortable for the user, safer and more efficient at producing the desired quality of samples, and less traumatic for the patient. 
​The success of the product development effort in achieving these goals can be directly attributed to the design process which was employed throughout the project.



The Device, and How it is Used
The bone marrow biopsy needle is used during a non-surgical, but invasive procedure intended to determine the state of disease, or the progress of treatment, in a patient.  Samples of both aspirant (liquified bone marrow) and marrow are taken, and later analyzed in the lab.  The biopsy needle is used to penetrate the patient's skin and flesh, and into the bone, usually at the iliac crest of the pelvis.
The needle is a manual device, consisting of a handle, stylet, and cannula.  Handle and cannula are fixed together, usually by overmolding the handle around the cannula.  The cannula is a hollow stainless steel tube, ground to a sharp point at the distal end.  The stylet is a solid stainless steel rod, residing inside the cannula, and providing additional strength to the cannula.  The stylet protrudes beyond the distal tip of the cannula by a few thousandths of an inch, and provides the drilling point necessary for penetrating through the bone.
After the area around the point of penetration is numbed, a small incision is made, to allow easier entry of the cannula.  The needle is then inserted through the incision, and carefully maneuvered through the flesh until contact is made with the bone's surface.  Once it has been determined that the stylet tip is securely situated on the bone, pressure is applied to the needle, and with a back-and-forth rotation of the wrist and forearm, the needle is "drilled" into the bone. When the needle has penetrated the cortex of the bone, the stylet is removed and a syringe is attached to a luer-type lock at the proximal end of the cannula.  The syringe is used to pull an aspirant sample from the marrow.  After an aspirant sample is obtained, the syringe is removed, the proximal end of the cannula is recapped, and the cannula is drilled further into the marrow.  This is accomplished using rapid twisting motions, to cut the marrow, and obtain a continuous "core sample" of tissue. When the physician or technician is satisfied that he has obtained a sufficient marrow sample, he removes the needle, and uses a probe slightly longer than than the stylet to gently push the sample out out of the proximal end of the cannula into a sterile lab container.  The procedure may be repeated to obtain additional samples.

Setting and Validating Design Goals
The product development process began with important research into methods of use of existing products, to determine perceived strengths and weaknesses.  We began our research by putting together a team made up of the industrial designers, a project engineer, and a marketing representative from Baxter. The industrial designers had been provided with a video presentation showing a biopsy procedure, and had studied the video in order to make some initial assumptions about methods of use, problems associated with existing devices, and ways in which these problems might be solved.  Examples of needles in current use were also studied, to provide additional clues about methods of use, manufacture, and assembly.

At this point, we felt that we had a sufficient understanding of the procedure and the device to enable us to generate a list of design goals.  The list included goals for the ergonomic aspects of the needle, as well as for the manufacture, assembly, distribution, and marketing requirements of the product.  A comprehensive goal list provides a framework within which to begin design, but it must also be subject to modification as the project progresses.

In order to validate our goals, we developed a survey for users of biopsy needles at hospitals and clinics.  An essential part of the survey was to put examples of design concepts into the hands of survey participants.  Frequently, a verbal or written approach alone does not produce consistent, thoughtful, or even truthful responses to survey questions.  Respondents are much more likely to express valid opinions when they are given something real with which to make comparisons or references. The design team launched into form-study modeling in high-density urethane foam, creating variations on the existing shape, as well as many radical departures from the currently accepted forms.  These study models were primed and painted, given steel-rod cannulas, and evaluated by other team members at Baxter.  Team members suggested the elimination of several form-study models, and modifications to others.  When we had made modifications and additions to the models, they were sent to a prototype fabricator, who poured silicone molds, and used the molds to cast solid urethane parts.  The urethane parts were finished, and were ready to be used in our survey. Concurrently with the preparation of the prototype models, we were also assembling a survey questionnaire, to accompany the models.  The questionnaire needed to be concise in its wording, understandable, and short - one side of one page.  The end result was essentially graphical, showing silhouette views of all of the study models.  Corresponding reference numbers were also provided, and participants were asked to circle and rank their favorites.  Other requested information included the number of procedures performed in a week, and which manufacturer's device was currently preferred.


Gathering User Information
Baxter field sales representatives provided us with access to the hospitals and clinics where biopsy procedures were being performed.  The sales reps knew with whom to talk at each location, who was using which products, and who was happy or unhappy with their current products.  They were invaluable in creating the opportunities for presenting the survey. All three design team members were present at the presentation of the surveys.  Groups of participants numbered from two or three up to thirty.  One of the team members would give an initial orientation, indicating our intentions in presenting the survey, and describing our method of administering it.  We kept the introduction brief, to allow as much time as possible for information-gathering. All of the team members acted to gather additional information beyond what was presented on the questionnaire, by talking individually with the respondents, answering questions, observing reactions to different configurations, and asking additional questions.  This informal part of the survey proved to be extremely valuable, providing us with information beyond what was going to come out of the questionnaire. A most interesting aspect of this part of the survey was observing users describe how they performed a procedure, and how they used the biopsy needle.  On several occasions, the user's verbal description differed significantly from the actual way in which he held or demonstrated his use of the needle.  Some respondents indicated that they had no problems with their current needle, except for needing to wrap their current product's handle in gauze in order to avoid blistering their palms during a procedure.


Synthesizing Information and Design
The next step in the product development cycle was to gather all of the information from all the various sources, and incorporate it into our project goals.  We had seen actual procedures performed, talked to physicians and technicians, analyzed current device configurations, and tabulated data from survey questionnaires.  Our project goals needed to reflect the issues brought out by these sources.  The modified project goals not only drive the creation of design concepts, but also can be used as a "punch list" to evaluate each
configuration during the subsequent stages of design. 
Survey results showed that the more radical ergonomic forms were not accepted as readily as the more traditional-appearing configurations.  Informal discussions with users had shown us that they appreciated the way that the more ergonomically-oriented forms felt in their hands, but the questionnaires revealed that the more recognizable forms ranked as the most desirable.  This led to the decision to incorporate as many of the ergonomic features as possible into a more traditional, recognizable configuration.  The new needle would need to have the appeal and psychological comfort of a recognizable form, but possess advanced ergonomic qualities which would differentiate it from its competition in the marketplace. There were four configurations which emerged from the surveys as contenders for continued development.  We refined these designs, fabricated more urethane models, and went back to the users in the field for further critical evaluation.  It soon became clear which one was preferred by the physicians and technicians.  We felt comfortable that this configuration was ready to be developed into a functional prototype.
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Finishing it Up
The industrial designers refined the concept configuration, incorporating features which addressed the project goals, and passed design control documentation of the needle and its parts to the engineers.  The engineering team modeled the parts in ProEngineer, and sent files out to prototype in stereo lithography.

The organic shape of the handle required several iterations of this process to get 100% correct.  Our goal was to insure that the design intent was maintained through the engineering process, and that the final model was completed to everyone's satisfaction, prior to submission to manufacturing.

There were two keys to the success of this product development effort.  The first was the creation of a cross-functional design team.  The second was our use of a process which began with a strong program of research into the actual needs of physicians, and their patterns of use of bone marrow biopsy needles in the field.  The designers were able to incorporate the knowledge gained into every aspect of the project - from the initial goals to the final design.

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Colorado Industrial Designer • Industrial Design for Technology Products • Colorado Design Firm
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