Physicians are exposed to harmful X-rays during routine interventional procedures. By integrating surgical robots with interventional techniques, interventional surgical robots allow physicians to remotely control catheters and wires outside the catheterization laboratory, thus protecting them from X-rays. Moreover, they can transform physicians' hand movements into more precise mechanical motions to improve patient outcomes.
This article studies the development of interventional surgical robots in China and their existing problems, starting with a comparison between surgical and interventional surgical robots.
1. Surgical robots VS Interventional surgical robots
A surgical robot is a kind of precision medical equipment integrating multiple disciplines. A transparent imaging system and flexible manipulator assist surgeons in achieving precise operations at narrow surgical sites in a minimally invasive surgical format.
From a clinical application perspective, interventional surgical robots can be applied in pan-vascular surgery, natural orifice transluminal surgery, percutaneous intervention and neurosurgery. Surgical robots are used more widely, including laparoscopy and orthopedics.
Global surgery is striving to enter the era of robotics. In terms of market size, the global surgical robot market reached USD 8.32 billion in 2020, with a five-year CAGR of 22.6%. The commercialization of laparoscopic surgical robots has been the most successful, followed by orthopedic surgical robots. Interventional surgery is nowhere near the scale of surgical robots.
In light of market share, the United States accounts for more than half of the global surgical robot market, with significant room for improvement in market penetration in Europe and China.
Despite the potentially massive demand for surgical robots for routine minimally invasive procedures in China due to its high population base, the size of the Chinese surgical robot market was only USD 425 million in 2020, accounting for only 5.1% of the global market. For interventional surgical robots, the international competitive landscape is the same, with the United States, Europe and other developed regions being the leading markets.
2. Development of interventional surgical robots in China
As medical technology evolves and people's medical needs improve, the burgeoning field of interventional medicine has played an integral role in clinical application. Minimally invasive interventions have developed rapidly in various areas, including cardiovascular, neurology, aortic and peripheral vascular, endoscopy and oncology. The global market for interventional surgical robots is booming, and there is a blue ocean for the Chinese market.
(1) Pan-vascular interventional surgical robot
Robot-assisted pan-vascular surgery in China is still at a relatively early developing stage. In China, the market size is expected to reach USD 180 million by 2026 due to the increasing prevalence of coronary artery disease and the gradual improvement in the availability of pan-vascular surgical robots.
The number of robot-assisted pan-vascular procedures performed annually is projected to increase to 140,000 by 2026, with a CAGR of 231.2% from 2022. With the penetration of robot-assisted pan-vascular surgery, the newly installed pan-vascular interventional robots need to be scaled up, with a projected penetration rate of 3% by 2026.
No pan-vascular interventional surgical robots are approved by NMPA in China currently. Cathbot (Shanghai) Robot Co., Ltd. (Chinese：知脉（上海）机器人有限公司), a joint venture between Shanghai MicroPort MedBot (Group) Co., Ltd. (Chinese：微创®机器人) and Robocath S.A.S (France), recently announced the completion of the registration clinical trial for R-ONE™, a vascular interventional surgical robot it introduced to China, making it the first robotic system for vascular intervention to have completed a multicenter clinical trial in China on May 26, 2022.
(2) Natural orifice transluminal surgical robot
The global market for natural orifice transluminal surgical robots has been expanding recently. China's first batch of natural orifice transluminal surgical robots is expected to be commercially available in 2023, when the market size will reach CNY 51 million (USD 7.06 million) and continue to grow to CNY 3.55 billion (USD 490 million) in 2030, with a CAGR rate of 83.6%.
Robot-assisted natural orifice transluminal endoscopic surgery (NOTES) is a new surgical technique that breaks the limit of the development level of instrument technology. It can diagnose diseases and perform surgery by placing a controlled flexible endoscope in natural orifices, such as the respiratory and digestive tracts.
The volume of robot-assisted NOTES operations in China will exceed 100 in 2023 and is expected to exceed 153,000 by 2030, representing a CAGR of 184.5%. In China, no existing natural orifice transluminal surgical robot products launched in the United States or the European Union have received NMPA approval.
(3) Percutaneous interventional surgical robot
Percutaneous surgery is prevalent worldwide as a standard diagnostic and therapeutic procedure and is expected to increase steadily in the coming years.
Advances in robot-assisted technologies and the expected increasing availability of percutaneous interventional surgical robots in China are driving the market's high boom growth. The Chinese market for percutaneous surgical robots is expected to grow to USD 264 million by 2026 at a CAGR of 52.7 percent from 2020. The number of robot-assisted percutaneous procedures will reach 246,501 by 2026, growing at a CAGR of 48.9% from 2020, with an expected penetration rate of 9.5%. Given the development and commercialization of surgical robots, the number of newly installed percutaneous surgical robots will continue to rise.
There are four dominant enterprises in the Chinese percutaneous surgical robot market, with five approved products. MAXIO V2 and Robio EX developed by Perfint Healthcare, ig4 developed by Veran, IQQA-Guide developed by EDDA Technology (Chinese：医达健康) and Savior-L developed by Accumed Technology (Chinese：精劢医疗) were approved by NMPA in succession from 2014 to 2021.
3. Existing problems of interventional surgical robots
The technical barriers are exceptionally high for interventional robots, which incorporate knowledge from fields such as artificial intelligence, mechanics, electrics, biological simulation, and image navigation. The Chinese interventional robot market is promising, but several unresolved problems remain.
Force feedback is the sensory nerve of interventional surgical robots, but its clinical application is not yet mature. Based on force feedback technology, the interventional surgical robot can accurately perceive the instrument force during the procedure and transmit the instrument resistance to the physician in real time. The slave manipulator can transfer external forces back to the master console, but the forces at the two ends are not transmitted by 1:1, which needs to be adjusted on demand. In practice, the friction between the instruments and the sterile sleeve also affects the accuracy of force feedback. Moreover, due to the master-slave operation, delays in force feedback will disrupt the physician's operation pace and cause the loss of real-time control of the manipulator, especially in the remote control. Tactile feedback, another crucial sensory information, is still in the research stage.
Image navigation is the eye and brain of interventional surgical robots. Vascular interventional surgery is performed under the navigation of images. Presently, 2D angiograms, the primary navigating images in clinical practice, suffer from severe tissue overlap problems and are difficult to direct physicians to operate instruments. Surgical image navigation should be able to integrate various types of medical images, such as CTA (Computed Tomography Angiography) and MRI (Magnetic Resonance Imaging), and reconstruct the 3D vascular model of the patient so that physicians can observe the overall morphology of the lesion and its relationship with the surrounding structure.
Precision motion control is a critical technology for interventional surgical robots. Vascular interventional surgical robots are equipped with tremor filtering algorithms that automatically filter out unnecessary physiological tremors from the physician at the master console. Due to the flexible joints of the manipulator, residual vibrations are generated, which is a significant reason to affect the accuracy of operation. The residual vibrations can be suppressed by active control of the manipulator. Second, the more degrees of freedom of the manipulator, the larger the motion space. However, with more degrees of freedom, the rigidity of the manipulator decreases.
Covering the whole process of interventional procedures is premised on satisfying the coordination of multiple instruments. Some vascular interventional surgical robots can only push guide wires, catheters or stents individually and cannot adequately simulate physician operations, requiring human assistance. If the wire is withdrawn from the guide catheter before the contrast agent is injected, manual manipulation is needed, and physicians are still exposed to radiation.
The breakthrough of a single technology is only a matter of time. The iterative speed and clinical adaptability of interventional products are critical barriers. We expect the advent of interventional surgical robots that are more aligned with physician usage habits and more accessible for clinical applications.