Robots will enter the OR

DN Staff

June 7, 1999

5 Min Read
Robots will enter the OR

Not so far in the future, paramedics may not transport all patients in need of emergency care to a hospital; some situations will warrant bringing the operating room to the patient. Robotic arms, set up by an attending medic and guided by skilled physicians many miles away, will perform the surgery.

Proponents of telesurgery envision early applications on the battlefield or even further afield--in outer space. The technology needed, they argue, is available already: precise servomechanics, force-feedback sensors for tactile "feel," motion scaling software, remote communications links, and the algorithms necessary for motion control.

Indeed, these are the features that comprise a computer-enhanced, minimally invasive surgery (MIS) system recently introduced by Intuitive Surgical Inc. (Mountain View, CA). Applying licensed technology originally developed for telesurgical applications, the IntuitiveTM system combines the natural hand movements of traditional open surgery with the less traumatic approach of MIS.

Applicable across surgical disciplines, with cardiac surgery as the initial clinical focus, the Intuitive system features three major component groups: robotic arms, electro-mechanical wrists, and a remote viewing console/operator interface. Operation is as follows:

Seven degrees of freedom. Soon after the patient arrives in the operating room, the surgeon makes tiny incisions less than one cm wide, and inserts special tubes called cannulas. These tubes create ports into the body and protect surrounding tissue. Then, the surgical team maneuvers three robotic arms into position near the patient.

Each arm serves as a carriage for the endoscope and pencil-thin tools to be inserted through the incisions. A sliding coupler holds the tool to the arm. Three motors control arm movement. Two drive the arm forward and back, left and right; the other moves the coupler up and down for tool insertion. Together, these three degrees of freedom replicate the surgeon's shoulder and elbow motion.

EndoWristTM technology at the end of each tool provides four additional degrees of freedom: inner pitch and yaw, roll, and grip. Inner pitch is the movement the human wrist makes when one knocks on a door. Inner yaw is the side-to-side movement associated with waving or wiping a table.

Four 25-mm motors, housed at the base of each robotic arm, drive the EndoWrist via cable technology, while four digital signal processors (DSPs) comprise the Intuitive control system. Capable of performing 300 million calculations in a single second, the DSPs direct and maintain every one of the motors driving the robotic arms and EndoWrists via encoder feedback signals.

Remote interface. The surgeon, while viewing the endoscope video feed, controls the tools through remote, yet familiar instrument handles that can be rotated, advanced, tilted, and withdrawn. Rather than bending over the patient, he or she operates from a seated position with the arms in a natural and relaxed orientation.

Motion scaling software, embedded in the motor controller, translates the surgeon's large natural movements to extremely precise micro-movements within the EndoWrists. Motion scaling software also translates every movement the surgeon makes to an identical, though scaled-down, movement at the surgical site.

Without such software, other MIS systems are "counter-intuitive," reversing the surgeon's natural motion. This is because the surgical tools pivot against the point at which they enter the body. Motion scaling software, combined with EndoWrist technology, enables the surgeon to reach around, beyond, and behind delicate body structures as if he or she were performing the operation directly.

With Intuitive's minimally invasive surgical system, surgeons maneuver tools via remote handles. Motor controllers and force feedback data reproduce these movements in the surgical field.

"Such innovations," claims Frederic Moll, MD and co-founder of Intuitive Surgical Inc., "will not only promote the use of minimally invasive surgical procedures, but its associated benefits: faster recovery times, fewer complications, and better healing." As Moll points out, "MIS has only begun to make its impact felt, comprising just 15% of all surgeries today."

And telesurgery? "Technically, we have the tools to do it," says Marketing Manager Daniel Hawkins, "but the present focus is in the operating room."

Enabling technology

  • Servomechanics

  • Force-feedback sensors

  • Motion-scaling software

  • Remote communi cations links

Technology hurdle

Ability to precisely control motion

Timeline for design

June 30, 1998--At Broussais Hospital in Paris, Dr. Didier Loulmet and Professor Alain Carpentier performed the world's first "closed chest" videoscopic coronary artery bypass graft procedure.

September 21, 1998--Intuitive Surgical announces the completion of 100 operations using its MIS system.

December 11, 1998--Doctors Hugo Vanermen, chief of Cardiac and Thoracic Surgery, and Frank Van Praet of the Onze-Lieve-Vrouw Clinic in Aalst, Belgium, successfully complete the repair of a congenital heart defect, or atrial-septal defect (ASD).

January 29, 1999--Receipt of approval to apply the CE mark for Intuitive Surgical's computer enhanced surgery system from D.G.M. in Denmark, allowing sale throughout the European Community. D.G.M. is a Notified Body to the Medical Device Directive.

June 1999--FDA clearance process underway in the U.S.

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