The robot nurse

Surgeon Michael R. Treat and his team at Robotic Surgical Tech have developed a robotic surgical assistant, named Penelope, to organise and manage all the surgical instruments used in an operating theatre – essentially replacing all the jobs usually assigned to a scrub nurse.

The Penelope robot itself is comprised of four major hardware and software components: the robotic arm, the instrument platform, the system stand, and the system control software.

Penelope has a 5 degree-of-freedom robotic arm with an electromagnetic gripper that move surgical instruments around. It unpacks instruments from the back tray, arranges them on a Mayo stand, and then hands them to the surgeon.

The arm’s electromagnetic gripper can pick up surgical instruments weighing up to 8 ounces. A magnetic gripper was chosen for the design, since it is far simpler to design, cheaper to manufacture, and more reliable; it’s also safer since the instruments aren’t held too tightly.

The instrument platform is a set of sterile horizontal surfaces on which Penelope stores instruments. These are called instrument caches and they’re designated by levels indicating their proximity to the surgeon. The instrument caches are the Mayo Stand (1st level), the staging zone (2nd level), and the back tray (3rd level).

The Mayo stand is the 1st level instrument cache. Penelope will keep those instruments most likely to be needed in the near term on the Mayo stand, where they can delivered quickly. Penelope continually monitors the progress of the operation and makes predictions about which instruments will be needed soon. Those instruments are kept front and centre on the Mayo stand, ready to be handed quickly to the surgeon.

The staging zone is the 2nd level instrument cache. Penelope uses this as an overflow area if the number of instruments becomes too large to fit on the Mayo stand. Delivery time from the staging zone is longer than for the Mayo stand, so Penelope will use this area for instruments less likely to be used.

The back tray is the 3rd level instrument cache. Before the procedure, the entire set of surgical instruments is sterilely packed onto the back tray. Instruments are then removed from the back tray as the procedure progresses.

Penelope’s base is a wheeled cart called the system stand. The instrument platform and robotic arm sit on top of this stand, allowing it to be adjusted and manoeuvred to the most convenient place for the surgeon.

The system stand also houses much of the electronics that keep Penelope moving. The main CPU is located in the system stand, as are the camera stand, holding Penelope’s digital camera above the instrument platform, and a microphone and speakers.

All of Penelope’s functions are made possible by the application of artificial intelligence software.

Penelope uses voice recognition to respond to a surgeon’s request for an instrument, handing it to the surgeon with a robotic arm. Using a visual processing capability, Penelope also retrieves the instrument when it is no longer needed. For safety, the robot even assists in keeping track of the number of surgical instruments used, helping to ensure that none are accidentally left inside the patient!

Penelope anticipates which instrument the surgeon will need next and selects that item from its tool kit, just as an experienced scrub nurse would. And like a nurse, Penelope can learn the instrument preferences of various surgeons.

While Penelope does not interact directly with patients, she can free the scrub nurse to do just that.