Medical robotics pioneer powers forward patients and physicians
Published on 10 Feb 2021

As an internationally recognised pioneer in robotic technology for medical and surgical applications, Dr Samuel Au Kwok Wai (Croucher Scholarship 2002) has had the great satisfaction of helping people who have lost a leg literally take a major step forward.

He has done so through his co-invention of a revolutionary robotic ankle foot prosthesis that went on to become a world-leading commercial product, PowerFoot One. More recently, he has helped devise a tiny robot-assisted catheter to assist surgeons conduct lung nodule biopsies to test for cancer.

Au is now an Associate Professor in the Department of Mechanical and Automation Engineering (MAE) at the Chinese University of Hong Kong (CUHK), where he is bringing the eight years of industrial expertise he gained in Silicon Valley after completing his PhD at Massachusetts Institute of Technology (MIT), together with his love of research, in a search for new directions in surgical robotics.

His interest in such work began during his undergraduate studies at CUHK, following an inspirational lecture by Professor Xu Yangsheng, currently the President of The Chinese University of Hong Kong, Shenzhen.

Xu had recently joined CUHK from the United States and gave a presentation to students about his work in robotics. For Au, it proved a life-changing experience. After seeing a video of the robots that Xu had built at Carnegie Mellon University, Au’s enthusiasm was ignited and his professional career path became clear.

Following his MPhil at CUHK, Au then embarked on PhD studies at MIT over seven years. That direction quickly revealed itself when he and his PhD supervisor, Professor Hugh Herr, came up with the breakthrough ankle-foot prothesis prototype, which mimicked the action of a biological ankle.

“We found old literature with evidence that conventional prosthetics use 30% more energy than natural limbs,” Au said. The MIT team then invested a huge amount of time working on a robotic alternative that was compact and lightweight but could provide sufficient energy. “That was the challenge,” he said.

After testing the prototype on many amputees, the researchers found it brought a 20% improvement on the metabolic cost of walking compared with a conventional passive prosthesis. It also helped users walk faster and with more energy while maintaining a natural gait at variable walking speeds.

The MIT Robotic Ankle-foot Prosthesis was named one of the Best Inventions of the Year by TIME Magazine in 2007 and later commercialised by iWalk, Inc.

After his highly successful PhD, Au decided to focus his research on surgical applications, seeing limitless potential for robotics improving surgical intervention. He also elected to enter industry and joined Intuitive Surgical, Inc, located in Sunnyvale, California, at the heart of Silicon Valley.

Intuitive is a front-runner in the development of robotic surgical systems and the company’s da Vinci system was one of the first robotically assisted, minimally invasive surgical systems approved by the US Food and Drug Administration.

Despite the impressive company credentials, Au says it was a “difficult choice” to go into industry, where he quickly realised key differences with the academic world he had just left behind. Rather than building demos or proof-of-concept models, in a company, the focus was how to build a robot into a stable commercial product for users.

However, given Au’s major motivation was to see robotic technology applied in real life, he accepted the challenge from Intuitive Surgical to imagine the impossible. “All I knew was that they wanted to build a new version of the Da Vinci system, so what we did in 2008 was… brainstorm on how to push the limits on surgical robotics.”

In his subsequent eight years at the company he helped to create two new da Vinci platforms: the ION and Single-Site. The da Vinci ION was a completely new platform, designed for early stage lung cancer diagnosis and approved for commercial use in February 2019.

The ION system consists of a tiny robot-assisted catheter to enable doctors to conduct accurate lung nodule biopsy deep within the peripheral lung regions. Accessing the body through natural orifices, the articulating robotic catheter, with an outer diameter less than 4 mm, is able to move over 90 degrees in all directions, allowing a physician to navigate the catheter through small and tortuous airways to reach nodules.

Since September 2019, physicians at El Camino Health in California have started to commercially offer a robotic lung nodule biopsy procedure to their patients.

By then, though, Au had already been back in Hong Kong for three years, after deciding to take up his current position at MAE in 2016. “Ideally, we must keep learning from both sides, which is why I returned to academia,” he said.

At CUHK, one of Au’s primary goals is to build a low-cost surgical robot to enhance physicians’ and patients’ access to robotic surgical technology.

“This is my personal passion and mission,” he said. “Nowadays, the cost of building a normal surgical robot is like building a Ferrari race car. That prevents the general public from receiving the benefits of robotic surgery. I believe we need to put more effort into inventing a BMW/Honda Civic type of robotic surgical system to allow more patients to assess the technology.”

Specifically, Au is working on an articulated type of robot designed to access the small, confined spaces of the sinus cavity for ear, nose and throat (ENT) surgical applications. To achieve this, he is developing smaller robots and different types of tools that can access and repair tissue with high precision while reducing trauma and collateral damage.

Take the passive but flexible catheter, for example. Its precision is low and only suitable for tasks such as opening a balloon, Au noted. “But if we add motorised controls to precisely operate it, this can enhance the capabilities of [surgical] tools,” he said.

In the future, Au explained, it will not be necessary to cut open the skin at all. Instead, the patient’s natural orifices will be used and the entire surgical procedure done automatically. Indeed, he predicted that this might be available for some ENT procedures in as little as five years, though it could still take 20-25 years for robotic surgery to be used for many other types of operations.

To help drive this medical revolution, Au has teamed up with eminent CUHK professor and surgeon Professor Philip Chiu Wai Yan to co-head the Multi-Scale Medical Robotic Centre under the InnoHK programme at Hong Kong Science Park, which is due to open in 2020. The Centre is set to bridge the gap between engineering knowledge and clinical expertise, and advance innovation. Au and Yan have established an early signing ceremony with other overseas universities e.g JHU, Imperial College London, and ETH Zurich.

InnoHK is a HK$10 billion funding programme to support top local and overseas universities in elevating Hong Kong’s research and development capabilities and accelerating commercialisation of R&D results and technology transfer. “This is exactly how I can bring my experience from industry back to academia,” Au said. And create another step forward – this time for Hong Kong.

Dr Samuel Au Kwok Wai is an Associate Professor in the Department of Mechanical and Automation Engineering at Chinese University of Hong Kong (CUHK). Before joining the University, he was Manager of Systems Analysis, New Product Development Department, at Intuitive Surgical, Inc. Au received his BEng and MPhil in Mechanical and Automation Engineering from CUHK in 1997 and 1999 respectively. He completed his PhD in Mechanical Engineering at MIT in 2007, assisted by a Croucher Scholarship awarded in 2002. Dr Au is the author and co-author of over 12 peer-reviewed manuscripts and conference journals, and has more than 20 patents pending. His inventions and research have been featured in media outlets, such as The New York Times and Technology Review. He has won numerous awards including First Prize in the American Society of Mechanical Engineers (ASME) Student Mechanism Design Competition in 2007, Intuitive Surgical (ISI) Problem Solving Award in 2010, and Intuitive Surgical (ISI) Inventor Award in 2011. Dr Au received his Croucher Scholarship in 2002.

Extended reading:

  1. Prof Samuel Au’s personal page (The Croucher Foundation):
  2. Prof Samuel Au’s personal page (The Chinese University of Hong Kong):