Acoustic Energy Emitters May Soon Eliminate the Need for Incision During Surgery

Surgery Without Cutting

Surgery is a medical field that has made tremendous progress in the past. First with general anesthesia, then increasingly advanced procedures and precise tools, and more recently robots, as we discussed in “Top 5 Robotic Surgery Stocks” and “Sony Showcases Surgical Precision with Robotics in Recent Microsurgery Demo”.

This progress has allowed surgery to become increasingly less invasive. Today, a very small entry point is usually enough, barely leaving a scar, reducing bleeding, and shortening the recovery period.

Robotics might make surgery even better in the near future, thanks to researchers testing a way to perform surgery without opening an incision on the body at all. And they achieved this by using only sound waves.

This project was conducted by researchers at the Virginia Polytechnic Institute and State University, University of North Carolina, and Michigan State University.

Sound-Based Surgery

In their publication titled “Robot-assisted chirality-tunable acoustic vortex tweezers for contactless, multifunctional, 4-DOF object manipulation”, the researchers focused on places in the body that surgery robots are struggling to reach—for example, regions shielded by tissue and bone barriers.

To improve access, they used “chirality-tunable acoustic vortex tweezers“, essentially an ultrasound wave emitter designed to move an object at a distance.

Because sound waves travel throughout the body, they can move on-demand particles or  micro- to millimeter-sized objects inside the body without direct contact. This control included “controlling object rotation, and translating objects along arbitrary-shaped paths.”

The acoustic vortex beam can be moved at the micrometer scale. Accordingly, the particle trapping area can be precisely set in a 3D space, and moving a particle after its capture can be engineered. When moving a tiny object along the winding path of a blood vessel, this can be a critical feature.

Zhenhua Tian, Assistant Professor At Virginia Tech.

How Does It Work?

Acoustic tweezers are acoustic vortex fields that cross over one another to form tiny ring-shaped acoustic traps.

Not only can this act through bones or tissue, but it can also move cells, drugs, or surgery devices inside veins. And move it precisely at the micrometer scale.

By combining the quickly improving concept of an acoustic tweezer with a robot (similar to those used in surgery already), the researchers achieved for the first time contactless 4-degrees-of-freedom (4-DOF) manipulation. This means movement in all 3 dimensions of space as well as rotation.

The performance was also impressive due to the ability to manipulate objects ranging from micrometers to millimeter sizes, as well as allowing manipulation in a large 3D space of 10cm by 10cm by 10cm.

One last advancement was solving a common limitation of acoustic tweezers. Most require transparent materials for guiding the movement. Which of course would be self-defeating for surgery behind bones and biological tissues.

So, they combined the acoustic tweezer with an ultrasound probe. They also developed dedicated software to enable the probe to work despite the “noise” of the acoustic tweezer.

Our imaging algorithm minimizes the required pulse-echo cycles for collecting ultrasound signals and implements a frequency-domain filtering step to remove acoustic tweezer–induced signal noise.

Applications Beyond Surgery

Acoustic tweezers have already been used for a wide range of biological applications:

• Moving cells (micrometers) and entire fish larvae.
• Isolate extracellular vesicles for disease diagnosis, or isolate tumor cells.
• Arrange cells for bioprinting.
• Concentrate biomarkers for signal enhancement.
• Direct microrobots.

The technology could also be used beyond biology. For example to manipulate safely hazardous droplets, or to control the self-assembly of colloidal materials and the arranging of nanomaterials for composite fabrication.

So overall, this discovery is likely to be first applied to the field of surgery, but could later have further applications in targeted drug delivery, 3D bioprinting, and progress in material science, including nanomaterials.

Robotic Surgery Company

While one of the most advanced robotic surgery systems is sold by Intuitive Surgical (ISRG), the company has less expertise in ultrasound or endoscopy than some of its competitors.

So, it is likely that the first real-life medical application of sonic tweezers might come from medical device companies already adept at integrating together many medical device systems like robots or surgery tools.

1. Medtronic plc

Medtronic is a medical device leader, especially in surgery and intensive care. While the other segments could also be considered as afferent to it, the medical surgical segment of Medtronic represents $2.1B of revenues, out of a total of $7.7B.

The company has been growing through organic growth, thanks to a large percentage of the R&D budget ($2.7B in 2022) and acquisitions (9 in 2022 and $3.3 worth of further acquisitions considered for 2023).

Medtronic sees a massive opportunity for simpler, low-cost robotic surgery:

“only 2% of surgeries around the world are held with the assistance of robots. There’s 98% out there that needs to be done via robotically-assisted surgery but not today because of the cost and utilization burdens”

It is with that strategy in mind that Medtronic has developed the Hugo system.

It also sells the Mazor X Stealth spinal robot-assisted surgery device, thanks to its $1.7 billion acquisition of Mazor Robotics in December 2018.

Overall, the sterling reputation of Medtronics and its presence in virtually every hospital for at least some equipment gives it a good entry point to capture a solid part of the nascent robotic surgery market, either through internal development or acquisitions.

It also already sells endoscopic ultrasound systems, and its presence in cardiology could help apply the sonic tweezer technology to cardiovascular therapies and surgeries.

2. Stryker Corporation

Stryker is another leader in medical devices present in virtually every well-equipped hospital or clinic, treating up to 130 million patients annually. The largest segments are traumatology, endoscopy, and instruments.

The company invests heavily in innovation, with $1.45B in R&D in 2022. It is also a serial acquirer, with 3 acquisitions in 2021. Most of its sales have been to the US (74%), with plans to keep growing in foreign markets.

The company has been growing in the surgery segment, notably through its 2019 acquisition of OrthoSpace for orthopedic surgeries.

It also has the Mako, for a robotic-arm-assisted surgery dedicated to orthopedic surgery.

With a strong presence in trauma, neurology, spine, endoscopy, and other internal surgery, Stryker could be among the companies to benefit the most from incision-less surgery with acoustic tweezers.

With its strong focus on endoscopy and orthopedic surgery, Stryker is likely to become the robotic surgery leader in this segment, which is also growing due to an aging population.