Building a Better Punch Biopsy Tool for Diagnosing Skin Cancer


A team of students at John Hopkins University have developed an integrated system that makes it cheaper and easier to take samples.


One of the prototypes featured at NCIIA's Open Minds exhibition is the integrated punch biopsy from a team at Johns Hopkins. A punch biopsy is not a very complex procedure, but there are many little things needed to complete it that can be time consuming, costly, and somewhat wasteful. Often, clinicians will need the punch itself, scissors, forceps, and sometimes sutures and needle holders. The team at Hopkins identified this as an area to improve upon, and are developing a nearly completely integrated punch biopsy device that will punch out the sample, cut, and collect it all in one go. We had a chance to ask Dr. Robert Allen from the team a few questions.

What gave you the idea to come up with this concept?

For the Hopkins' BME undergraduate program, I, along with other CBID faculty, solicit and vet clinical problems identified by Hopkins' medical faculty each year. This year, faculty dermatologists Dr. Sewan Kang and Dr. Timothy Wang identified clinical problems associated with obtaining punch skin biopsies, a necessary procedure for skin cancer diagnosis. Nishant and his team selected this project to work on for the academic year 2011-2012.

What do you think the cost savings would be of your integrated biopsy vs. the currently standard kit?

This is difficult to answer. We have estimated that all the processes of the current procedure (including the punch tool itself, ancillary equipment, procedural costs, and professional fees) would well exceed $50 per biopsy. With our new technology, the procedure simplifies, fewer instruments need to be sterilized, and trained non-dermatologists may be capable of removing punch biopsies.

Have you gotten any feedback from clinicians using your device? What do they think so far?

Although not tested clinically yet, Drs. Kang Wang and colleagues have used the prototype on simulators and animal tissue. We often use clinical feedback -- which has been uniformly favorable -- to improve the design.

Can you describe how your device works?

The punch includes a wire that runs along the shaft of the punch tool and then loops flush along the inner surface of the blade. On being retracted, the wire constricts the sample and eventually cuts right through it. The design of the blade facilitates enough friction to collect the sample within it. For the closure, we are developing the use of the standard steri strip with a medical adhesive (as opposed to sutures). The reason for this is the decreased trauma to the patient, decreased clinical time for the procedure, and decreased material cost.

What's the make-up of your team?

Our student team comprises five upperclassmen who are biomedical engineering students at Johns Hopkins University. Four of them are juniors -- with Nishant being the faculty-selected team leader -- while one is a senior. In addition to Dr. Allen, support for the student team includes our clinical sponsors -- members of the JHMI dermatology department, additional JHU BME faculty, and a graduate student adviser. Ancillary personnel also help the team with machining and administering the project.

What was the biggest obstacle you have faced so far trying to make this concept a reality?

We have faced numerous challenges along the way. Although hard to pinpoint the biggest one, the miniature size (on the millimeter and fraction of a millimeter level) makes developing our solution uniquely challenging. While developing prototypes at much larger scale made development of the prototype easier to work with and visualize, the process of scaling down to the millimeter level brought on its own complications.

Here's a video the Hopkins team made discussing the value of the new device:

This post also appears on medGadget, an Atlantic partner site.

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