Latency and jitter are the final telecommunications challenges for telerobotics developers working to advance remote procedures as mainstream treatment options.
By Eduardo Fonseca, XCath
Dr. Jacques Marescaux of the Institute for Research into Cancer of the Digestive System (IRCAD) during the Lindbergh Operation in 2001. [Photo courtesy of IRCAD]
More than two decades after that breakthrough gallbladder removal (known as the Lindbergh Operation), telerobotics — treating emergent conditions through remote controlled robotics — is still in the labs of a small number of pioneering surgeons. Yet advancements in telerobotic capability have positioned the technology to uniquely impact specific areas of medicine — most notably, stroke treatment. Every year, 15 million people around the world suffer a stroke, and the patient risk of mortality or morbidity depends on how quickly they receive treatment.
With telerobotics, care providers can dramatically decrease time to treatment and increase access to the highest standard of stroke care — mechanical thrombectomy — particularly among rural and underserved patient populations. Rather than wasting time transporting patients to centralized stroke treatment centers, telerobotics platforms could bring high-quality care to any location with an internet connection. Given the multitude of costs, applying telerobotics within stroke treatment is both a humanitarian and an economic imperative.
Logistical obstacles remain for remote-operated surgeries, such as how to reconcile insurance coverage and legal responsibilities for a patient who is in a different location than the operating physician. But the two main technical challenges for telerobotics developers are latency and jitter.
Clinical impact: Latency vs. jitter
Physicians training on robotic surgery systems at the Institute for Research into Cancer of the Digestive System (IRCAD) in France. [Photo courtesy of IRCAD]
When moving medical devices within the vasculature, latency rates can make the difference between a properly or improperly placed stent or balloon. Challenges in overcoming latency include light speed delays from geographical distance, lack of control in the signal routing direction, and congestion in bandwidth variation. These affect the round trip time (RTT), or the duration in milliseconds from sending the initial browser request to receiving a response from the server.
Remote surgeon consoles, patient-facing surgical systems and additional auxiliary systems will most likely utilize a direct fiber optic connection at the onset of a telerobotic treatment program. These programs will require signal redundancy as a failsafe for potential network fluctuations or failures, and emerging 5G wireless networks could serve as an ideal backup. High-speed, high-bandwidth 5G networks have already shown the ability to have download speeds up to 10 times faster than incumbent 4G networks. They might also offer a safer connection for medical procedures because they can leverage multiple connections between two points, creating a “safety net” connection in case the primary (presumably direct fiber optic) connection fails.
A more dangerous hurdle, jitter, occurs when the bandwidth of a network connection fluctuates and compromises the quality of the signal. Fluctuations in network quality have been shown to increase surgeon fatigue and can lengthen the time of a procedure. In neurovascular procedures the surgeon must navigate tortuous vessels, an unstable environment that becomes exponentially more difficult to maneuver when network fluctuations add a new layer of instability. When placing a stent inside a brain, for instance, a fraction of a millimeter can make the difference between proper or improper placement. Surgeons need a consistent signal to move medical devices through the brain’s vasculature and place them as accurately as possible.
Several tactics to minimize the potential for jitter have already shown effectiveness. Packet prioritization creates an order of priority within the network so the most critical applications have the bandwidth they need. Similarly, it’s possible to reserve the amount of bandwidth needed for a specific application ahead of time, and enhancing the network buffer can mitigate fluctuations. Protocols and standards including real-time transport protocol (RTP), quality of service (QoS), or traffic engineering (TE) mechanisms can also play a part in combatting jitter.
Realizing the potential of remote procedures
Dr. Jacques Marescaux of the Institute for Research into Cancer of the Digestive System (IRCAD) [Photo courtesy of IRCAD]
Currently, the U.S. has only about 300 facilities that offer comprehensive stroke treatment for a population of more than 300 million people. By connecting those facilities to skilled physicians, they can exponentially expand the number of patients they can reach and create access to high-level treatment where no options currently exist. Network-connected care facilities also elevate the standard of care, as the most accomplished physicians can reach patients anytime, anywhere.
Ever since Marescaux introduced the potential of telerobotic procedures, our communications networks have increased in speed, bandwidth and capability, offering the infrastructure for telerobotics. With the birth of 5G and an array of tactics to mitigate challenges such as latency and jitter, our health system is on the verge of fully realizing the disruptive humanitarian and economic potential of robotic-powered remote procedures.
XCath CEO Eduardo Fonseca [Photo courtesy of XCath]
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The opinions expressed in this blog post are the author’s only and do not necessarily reflect those of Medical Design & Outsourcing or its employees.
