Bridge Design

The Detector is an injection port detection system for reconstructive surgical breast implants. Doctors use the Detector to find the re-sealable port on the surgical implant in order to inject a saline solution into the implant. By gradually stretching the patient’s skin, the implant is inflated with a saline solution. Every few weeks for up to 6 months a hypodermic needle and syringe are used to pump saline through the re-sealable injection port that contains a stainless steel disc. The detector makes finding this port an easy and accurate job for the health care professional.  To appreciate the new design it is important to understand the previous product that Mentor had developed prior to Bridge’s involvement.

A single sensor embedded in the probe looked for a peak signal. This older product required four steps:

• It must be tuned
• It must then be calibrated by sweeping it across the chest
• The chest is slowly scanned until the device peaks as the two upper green LEDs come on, indicating the port location
• A pen is then passed through a narrow hole in the center to mark the skin                                        

Not surprisingly, many users had trouble following these steps accurately, leaving a large margin for error.

The design challenge was to develop a much more user-friendly and reliable way to detect and mark the port, so the needle could accurately find its target up to 2” beneath the skin.  Mentor’s original attempt at designing the detector was complex to use, requiring a particular pen to mark the skin, needing specific attention not to angle the detector on the skin surface and repeated runs to confirm locations which at times still proved to be incorrect. The consequences of a missed port could mean minor surgery to remove a burst implant - so the design stakes were quite high.
The design challenges were:

• To greatly simplify the device and win back the customers with a product that gave great confidence to users
• To devise a more reliable system for locating the port 
• To make it easy to mark the port after it was found
• To make the device’s operation easy and self-evident without complex calibration issues
• To bring visual appeal and ergonomic comfort to the design
• To package the detector’s components compactly in a hand-held unit
• To create a detector that would be centered in the palm of the hand instead of having a “bicycle hand grip style” handle that introduced angular inaccuracy
• To make a product that would encourage doctors to use Mentor’s implant system rather than discouraging them

To re-design the product the designers started with the user interface. If detection was to be improved, we needed to create a new way of scanning the breast area. Mentor was reluctant to spend too much money on a more sophisticated interface without knowing it would be successful. To answer this question Bridge created an interactive computer model of a number of different approaches to port detection, with varying degrees of change to the detection and interface electronics.  This was like a video game –it randomized where the port was buried on an outline of a chest.  
Bridge then asked a number of potential users to try out the interface and see how good they were at finding the port.  Concept 1 (in the Flash demo here) is closest to the old product, and showed how hard it was to detect the port with only the limited “peak” information. Try detecting the port yourself by clicking on this window.
Bridge created other ideas including Concept 2 (in the Flash demo here) which was the favored idea for the new user interface.  Here the user gets clear directional information (arrows indicate which way to move to find the port) and a positive signal (all arrows go green) when they are over the target. However, it did require that the unit had three sensors to give this information instead of one. But it was so strongly preferred and better understood by users that it was the clear winner and was therefore implemented in the product, even though it cost a little more.

The design of the detector had to satisfy two divergent criteria: it needed to appeal to doctors and reassure patients.  For patients it was desirable that the units have a soft and friendly feel, as it is used intimately across the skin of women who have already seen many medical instruments and unpleasant procedures.  For doctors, with whom the detector itself is a sales tool for the implant procedure, the unit should look sophisticated, technical, and precise.

The solution shown here was a greatly simplified user interface that did not require any training or confusing calibration. Simple arrows direct the user to the port.
When the port is found, a well-placed plunger is depressed to gently mark the skin with a temporary dimple. Soft rubberized grips help make it a  palmable, soft, friendly-looking product with superb ambidextrous ergonomics that both doctors and patients love. User feedback is that this product is far easier and more intuitive to use when compared to the old product.