When making an incremental improvement to a product, there is often a part that is not proprietary, that had been in clinical use for decades.
Figure 7.6 Assortment of medical devices for R&D.
Many times, surgical devices were originally borrowed from one type of surgical procedure and pressed into service in another specialty, thus becoming embedded into surgical practice by use and convention. This offers opportunity for improvement and innovation. A new feature can be added to this system that is higher performance, less invasive or less traumatic to the patient, and uses an existing instrument, familiar to the surgeon as a platform for a new technology. An example of this is the ClearVu™ flexible arthroscopic cannula. (See Figure 7.7.)
The ClearVu device was designed to overcome the problems with rigid inflow-outflow cannulae commonly used in three-portal knee arthroscopy. Rigid metal cannulae were borrowed from the Veress needle, originally used in general surgery. Bob Bruce, an orthopedic physicians assistant in San Jose, CA, saw a need for a better cannula while observing the shortcomings of the rigid metal cannula in surgical practice. In arthroscopy, the joint space is distended with water, and the viewing scope and instruments are inserted into the joint through small incisions, or portals. Surgical efficiency depends on the surgeon having a constant flow of clear water through the joint, or the surgical field quickly becomes murky and obscured with blood and surgical debris.
The knee also needs to be bent during surgery, and the metal cannula does not bend. This caused the distal end of the cannula to become clogged with soft tissue and the inflexible cannula shaft to make dents in the sensitive articular cartilage of the inside joint surfaces of the knee. The main disadvantage to the surgeon was that when the rigid cannula dug into soft tissue at the distal end, the flow of fluid through the knee stopped and the surgical field quickly became murky and obscured by blood, and the sharp end of the cannula often skived and damaged articular cartilage.
In the process of designing the flexible section of the cannula, Bob discovered a number of innovative solutions to keep the cannula from collapsing and kinking during a procedure. Being a former U.S. Army Special Forces medic and an avid outdoorsman, he noticed that fishing rods were tapered to keep them from breaking when flexed. Bob adapted this observation to develop a patented progressively flexible tapered cannula, purpose built and optimized for consistent fluid flow during arthroscopic procedures.
Bob, being sensitive to surgeons' resistance to the unfamiliar, used an existing metal cannula, cut off the front of the cannula, and replaced it with a flexible plastic cannula shaft of his improved design and the familiar stopcock proximal end. Once this prototype was accepted by surgeons, he produced a molded version of the product. The Cannuflow® ClearVu™ is now being marketed worldwide and is a less traumatic, high-performance replacement for metal cannulae in three-portal arthroscopy. From the patient's point of view, there is less trauma and pain during and after surgery, and the arthroscopic surgeon can see what he is doing, without the surgical field being clouded with blood and debris.
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