Drilling out a hole in the base of the skull is particularly demanding of a surgeon; the procedure has to be done with extreme precision and often takes a lot of time. Researchers at TU Eindhoven have therefore developed an operating robot to take over this task. The robot can automatically and safely mill a cavity of the desired shape and dimensions with sub-millimetre precision. Jordan Bos received his PhD on 16 April on the robot, which he designed and built. The robot is expected to perform its first surgery within five years.
Surgeons make a hole in the base of the skull in more than a hundred thousand people worldwide every year, for example to treat an infection or cancer, or to insert a cochlear implant, a hearing implant. This is a delicate task as they encounter quite a few structures that they should definitely not touch, such as the optic and taste nerves, the inner ear and the balance organ. On top of this, bone filings and blood obstruct the view through the microscope during the procedure. The surgeon must therefore work with extreme concentration, often for hours at a time, in an uncomfortable position.
Studying surgery
At the request of ENT specialist and skull base surgeon Dirk Kunst of Radboud UMC in Nijmegen, Jordan Bos developed a robot to partly or completely take over this type of surgery. He first visited about 20 skull base surgeries to study these procedures, and then came up with about 20 concepts. From the best concept, he made a detailed design and built a prototype, which is now ready and with which the first technical tests have now been carried out.
Advanced arm
The robot, named RoBoSculpt, works on the basis of precise instructions from the surgeon. The latter accurately indicates on CT images of the patient's skull which piece of bone the robot should remove. The robot is actually a highly sophisticated arm, holding an existing surgical drill. Before surgery, the head is accurately fixed; then the robot drills and mills out the desired cavity.
Working through
Because the robot basically works faster, the duration of the procedure can be reduced. It is expected that the robot will enable more precise operations, with shorter recovery time, and that there will be fewer complications and recovery operations. This would make this type of surgery less stressful for the patient and less costly. Furthermore, surgeons may benefit by having a burdensome task taken over, which also removes a barrier to continue working into old age.
Seven axes
The robot is actually an advanced computer-controlled milling machine, or CNC milling machine. It has seven axes of movement to make all possible angles. Despite the high number of axes, the device is very precise, thanks to its compactness, high rigidity, low weight and minimal backlash on the axes. The robot can also be well covered with a sterile cover, which is important in the operating theatre.
Skull base surgeon Dirk Kunst, who co-supervised Bos as co-promoter, are enthusiastic about the robot. "This is an important step towards the operating theatre of the future. RoBoSculpt is an optimal collaboration between the surgeon and the machine; they really complement each other to achieve the best result for the patient."
Gaining experience
The first pre-clinical tests with the robot are therefore going to take place this year, at Radboud UMC. The first intervention on humans could take place in two to three years. A possible first step in terms of introduction is that the robot does the preparatory work, and the surgeon himself does the crucial last part, in order to gain experience with the robot in a safe way. It is planned that the company Eindhoven Medical Robotics, will take the robot to the market in collaboration with TU Eindhoven.
Not fixable
A robot that performs a surgical procedure pre-programmed is a new development. Nevertheless, Bos does not think that robots capable of performing all kinds of other operations will come along anytime soon. "The principle of this robot is only applicable for precision surgery on hard tissues, especially bone. Soft tissue cannot be fixed accurately enough."
Source: TU Eindhoven
Photo: Bart van Overbeeke
