When David Danitz was an 11 year old in San Diego, CA, his dad told him he should become a mechanical engineer. No, not a baseball player, not an astronaut, not president of the United States. Mechanical engineer.
“I used to tinker around in our garage, building go-karts or playing with Legos,” says Danitz. “I remember the moment I built a little mechanism to shoot a bow and arrow, he suggested I may want to think about becoming a mechanical engineer. Ever since then I knew what I wanted to do.”
In 2003, at the age of 33, Danitz filed a U.S. patent for an “articulating mechanism for remote manipulation of a surgical or diagnostic tool.” The patent was awarded in 2006 and the surgical tool is now revolutionizing surgery of the internal organs of the abdomen. Previously developed tools had limited range of motion, making it difficult to negotiate acute angles, increasing risk of trauma to surrounding tissues. The Holy Grail of abdominal surgery is an instrument that can work within a body in tight, tiny spaces and be easily steered outside the body by a surgeon.
Danitz's invention, called RealHand HD, offers complete seven degrees of freedom of movement in a handheld instrument and with no need for additional hardware. The key to the technology is multiple pairs of links and cables. Movement of one link of a pair causes corresponding relative movement of the other link of the pair. The relative movement at the distal end of the articulating mechanism corresponds to that at the proximal end. These new instruments are enabling surgeons to perform scarless surgery entirely through the belly button or other natural orifices.
Examples of other surgical or diagnostic tools that could use the mechanism include: endoscopes, catheters, Doppler flow meters, microphones, probes, retractors, dissectors, staplers, clamps, graspers, scissors or cutters and ablation or cauterizing elements.
The fact Danitz even wound up working on medical design is serendipitous. He finished a master's program in mechanical engineering at MIT and took a job in a design lab operated by Exxon. “After six months, the lab decreed it would do no more design work,” recalls Danitz. In 1998, he went to a company called Computer Motion in Santa Barbara, CA where he had the opportunity to develop expertise in surgical robots. It was Danitz's job there to develop an interface for joysticks that would be used by surgeons to operate tools.
In 2000, he joined Novare Surgical Systems in Cupertino, CA, where he originally worked on systems for atrial fibrillation. The idea was to develop an instrument that could go through the rib cage to work on the heart. “I knew there were snake robots out there,” says Danitz. “I was looking for a way to snake behind the heart and came up with the mechanism where you have links on the outside of the patient that are connected via cables to links that are on the inside. And when you bend a link on the outside, it has a mimicking effect on the inside.”
After significant prototyping, a workable medical instrument was developed and received 501(k) approval. Several other surgical uses are under development, including heart surgery. A Novare development engineer is working on a mechanical hand application. There are also potential applications in other market sectors, such as toys, auto repair and jet engine inspection.
For now, the RealHand is having a dramatic effect on abdominal surgery. In July, Novare announced the successful completion of the first pediatric single port splenectomy, using the instruments.