How it works
Perioperative management of patients is no different than conventional
surgery. We haven't created dramatic new protocols just because we're
using computers and robotics. This technology helps with the surgical
workflow by eliminating steps taken with conventional instrumentation
that can damage bone tissue. For example, surgeons traditionally run
metal rods through the marrow cavity of the tibia and femur to gauge
the angles of needed bone cuts. They often don't think twice about per-
forming this step, even though it causes substantial damage to bone tis-
sue. Working with computer-navigated, robotic-assisted technology
eliminates having to use the bone-damaging metal rods.
The robotic system I use requires the insertion of 4 pins — 2 affixed
to the tibia and 2 affixed to the femur. They serve as registration
posts, which let the robot's computer navigation system produce a 3D
map of the joint. The pins affixed to the femur are inserted through
the main skin incision; the other 2 are placed through puncture inci-
sions in the skin over the tibia. They create small holes in the bone,
but are much less damaging than the rods and jigs needed to deter-
mine cutting angles during conventional surgery.
A mobile computer workstation with a small receptor on top
receives signals from the pins placed in the patient's femur and tibia.
The non-sterile workstation is moved into the room once the patient
has been draped and positioned.
Before starting surgery, you must register the pins to tell the com-
puter which reference points you're using. The 4 pins placed earlier
act as 2 fixed array systems on the tibia and femur. You first place a
probe on points around the knee and ankle as instructed by the com-
puter. To complete the final registration, you rotate the hip in large cir-
cles. The computer senses where the center of the rotation occurs
around the femur and builds a 3D model that's displayed on the work-
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