Surgery in space IV

The final part on the series of post on the feasibility of extreme telesurgery deals with a provisionary concept of scaled telemedicine paradigm supporting long haul human space flights.
Based on the physical conditions, the difficulties listed in the previous post and on the system requirements, three-layered mission architecture is proposed to achieve the highest degree of performance possible, by combining robotic and human surgery. (See picture for more details.)
By adaptively switching, different levels of surgical service can be provided throughout the mission. Mainly within the range of 380 000 km (app. the Earth-Moon average distance), regular telesurgery techniques can be used in space to provide medical support in case of emergency. Leaving the orbit, special control strategies have to be applied, to extend the feasibility of telesurgery up to 2 s of delay. With robot assisted surgery, a shared control approach should be followed, integrating high-fidelity automated functions into the robot, to extend the capabilities of the human surgeon. This concept could be most beneficial for long duration on-orbit missions, primarily on board of the ISS. Presently, there is no other option than the immediate evacuation of the affected astronaut, which poses bigger health risk and costs a lot more. If losing the signal, the integrated robotic system should stop immediately, and the crew has to be prepared to take over the control of the robot, and finish the procedure, if the connection cannot be reestablished. To reduce the frequency of failure, network redundancy is essential as showed by the NEEMO projects.
Flying further from the Earth and having reached the limits of pseudo real-time communication, the procedures should be performed by the flight surgeon, or by any other trained astronaut, under the telementoring guidance of the master surgeons on the ground. As showed by the NASA undersea experiments, telementoring can be an effective alternative to direct teleoperation, allowing the controller to perform the tasks based on the visual and voice commands of the ground centre. With adequate training and practice, the astronauts with a basic surgical training might be able to successfully accomplish complete procedures. Telementoring may extend the boundaries of telepresence, as it can still be effective with a 50-70 s delay (within the range of app. 10 000 000 km). Upon this phase, the built-in semi-automatic functions of the surgical robot may have a significant role to improve the overall quality of the surgery. On one hand, motion scaling, adaptive tremor filtering, the automated following of the organ’s movement, automated suturing could significantly improve the less practiced crew members’ performance, while special security measures could also be applied on the other hand. The setting of virtual boundaries for the robot, tool limitations and speed constraints may reduce the risk of malpractice. Astronauts should also benefit from advanced imaging technologies, as accurately matched anatomic atlases could help their navigation around the organs. With the use of augmented reality systems, real and virtual images can be merged in real time to make the operation even smoother.
There is no sharp limit between telementoring and consultancy telemedicine. Above a certain time delay, the terrestrial medical support crew will not be able to react on time to unforeseeable events during the procedure. By the time they receive the video signal from the spacecraft, the operating environment might have drastically changed, therefore the astronauts should be able to perform the procedure on their own, after having consulted the ground centre. Above approximately one minute of delay, it is inconvenient and impractical for the crew to wait for the guidance of the ground after every step accomplished, and in some cases, it would endanger the success of the operation. The flight surgeon must be trained to conduct the operation and make decisions on its own.
If there is no real-time connection between the spacecraft and the ground control, the terrestrial surgical centre could still run complete surgical simulations. Given the astronauts’ precise 3D model gained for extensive MRI, CT and PET scanning prior to the mission, a variety of operations and possible outcomes could be simulated and analyzed on the ground. Complete risk assessment, identification of bottlenecks and personalized best-practice methods could be evaluated. The condition updates of the ill or injured crew member could be gained from Ultra Sound imaging and other scanning equipment on board, along with the data of biosensor-networks. These are to be merged with the recorded model before to the real operation; therefore the surgeons on Earth could provide a priori results and recommendations in the form of consultancy, prior to the actual in-space surgery.
It was shown during the NEEMO missions that the general performance of the telesurgery is higher than of the telemedicine, and a team of experts may do better than the flight surgeon. Therefore depending on the feasibility, telesurgery should be preferred on telementoring.