Did you know that to be able to say, “not this again,” in response to the current global health emergency, you would have to be no younger than 102 years old? It’s true. The last time the world saw such a crippling public health crisis, the year was 1918, when the flu pandemic sickened one-third of the world’s population. But, in the throes of a calamity unseen in over a century, which has now even shut down the world’s economy, one would think manufacturing would simply stop as well. And certainly, with unemployment figures estimated to be as high as 20 percent in the United States, the highest ever since the Great Depression, it isn’t difficult to imagine a slowdown in the making of virtually anything built by America’s proud stable of manufacturers.1

But when it comes to producing the mechanical cables and cable assemblies that reside inside the world’s medical devices, exoskeletons, prosthetics, and surgical robots, COVID-19 isn’t changing the pace, nor the demands of the scientists and engineers that design these life-bettering creations.

As a matter of fact, makers of medical, exoskeletal and surgical products that use cables have not skipped a beat in asking for materials that are stronger, smaller, longer-lasting, more flexible, and more complicated - and OEMs want to source them more quickly than ever.

Surgical Innovation Cannot Stop Even When the World Has

To understand why medical device, instrumentation, and robotics markets urgently move forward with the rollout of tomorrow’s next big surgical innovations, notwithstanding coronavirus, one must first understand the impact the world’s healthcare industry has on the global economy.

In the United States alone, healthcare represents nearly 18 percent of gross domestic product. What’s more, 16 million of the country’s workforce are healthcare professionals and represent 11 percent of all U.S. employees. Among that 11 percent are workers whose expertise deals directly in providing specialty care for people receiving and who have received elective and critical surgery.2

As a matter of fact, elective and critical surgery are resuming - literally as you read this article. In all four corners of the globe, despite a pandemic, someone is having a hip replaced, a heart valve repaired, or a knee rebuilt. What each of these seemingly unrelated surgical procedures have in common is the enormous economic influence tied to the healthcare networks, doctors, nurses, and occupational and physical therapists that care for these patients, before, during, and for months, sometimes years, after surgery. Said plainly: if a cardiac surgeon isn’t repairing a life-threatening condition known as atrial fibrillation, or an orthopedic surgeon isn’t installing a new hip joint, trillions of dollars are not being funneled into the economy, and likewise, millions of healthcare professionals cease having people to treat, repair, and rehabilitate.

Because so much of the revenue that hospitals, doctors, nurses, technicians, and other experts depend on comes from elective and critical surgical procedures, the devices, instruments, and robots used in such surgeries must be produced. Even more, specifically because of a pandemic’s assault on the most vulnerable populations right now, elective surgery can arguably become not-so-elective in an effort to protect those very people.

The Evolving Demands of Medical Mechanical Cable

The earliest known cord (rope) ever discovered comprised twisted fibers affixed to the end of primitive stone tools and dates as far back as 40,000 to as much as 50,000 years. And, 500 centuries later, industry is still attaching cord to tools - although today it is called wire rope or mechanical cable, even with a few traditionalist holdouts still attached to the word cord. And like any other innovation throughout the annals of time, mechanical cable has not been immune to the demands of developing markets, technology, and yes, evolution.

A 0.027 in. diameter (0.69 mm) 7 × 49 tungsten with fused ends. This sophisticated mechanical cable is used to actuate movement and support the surgical robot’s extremities during surgery. (Credit: Carl Stahl Sava Industries)

Over the last 20 years, especially the last decade, surgical robots and devices need more flexibility and more lifetime, yet a smaller footprint from their mechanical cables. To add to the growing demands placed on today’s life-saving wire rope, the faster they are installed inside these astonishing machines and instruments, the faster doctors can improve life - and in many cases, extend it.

Remembering the impact that elective surgery has on the world’s economy, it becomes rather easy to see why the medical device and surgical robotics markets, that use mechanical cable, must continue uninterrupted - even in the middle of a world crisis.

Smaller and More Complex

What makes today’s medical devices and surgical robotics mechanical cables so fascinating is that they are, in fact, smaller, but longer living, stronger, and more flexible. This amalgam of counterintuitive themes makes the production of these evolving cables that much more intriguing to manufacture.

As more companies emerge as makers of surgical robots, the requirements for the mechanical cables actuating the robot’s end-effectors demand maximizing competing characteristics such as small, but stronger; stronger, but flexible; flexible, but enduring.

Smaller commonly means weaker, right? But in the field of surgical robotics, smaller must achieve the strengths of larger diameter cables. This is often attained using new materials, including tungsten cable assemblies. With tungsten, one can typically realize upwards of 20 percent or greater increase in tensile strength for a given diameter, as compared with other materials. Cables found in surgical robots typically range in size from 0.015 up to 0.039 in. diameter. These cables are often comprised of tungsten wires smaller than 0.001 in. in diameter. For context, that’s wire one can barely see, let alone handle and string into the heavy machines that produce this sophisticated wire rope.

But it’s not enough that these cables are stronger than, say, their stainless-steel equivalent. They also must last far longer as well. In most cases, surgical robotics cables are run over extremely small pulleys - sometimes as small as 2 or 3 mm diameter. Because of these ultrasmall pulleys, standard stranding configurations often do not afford the flexibility required of the cable to achieve the life expectancy of the robot. Such common cable constructions that fall short include 7 × 7 and 7 × 19.

Therefore, new and evolving constructions have emerged and are expressly designed to achieve much greater flexibility over time. Constructions such as 8 × 19, 7 × 37, and 19 × 19 allow for far more flexibility and extended performance life, thus making these elegant and extremely expensive robots last longer, stay precise, and deliver reliable results. If surgical robotics makers were left at the mercy of 7 × 7 or 7 × 19, each of which comprises 49 and 133 wires respectively, the freedoms these robots require would simply not exist. However, with constructions like 7 × 37 and 19 × 37, for instance, the monofilament count grows from as little as 200 up to 703. These additional wires, in some case hundreds of them, ensure greater flexibility and lifetime.

Surgical robots mimic the surgeon’s fingers, wrists, elbows, arms, and shoulders, increasing both procedural precision as well as reducing the musculoskeletal stresses imposed upon the physician. (Credit: Carl Stahl Sava Industries)

Faster than Fast Go-to-Market Strategies

The surgical robotics market did not need help from coronavirus to accelerate its pace. It is already among the fastest-moving categories in the healthcare manufacturing world. But the pandemic certainly has greased the bearings. Now, increased emphasis has been placed on competition, yielding a marketplace fraught with companies introducing their surgical robots to clamoring buyers, at fevered speeds. This places greater weight on cable manufacturers to partner with robotics makers to minimize go-to-market delays, amid an unprecedented global health emergency.

With COVID-19, production capacities are down across many manufacturing sectors as a means of mitigating risks of producing too much product during a slowing or even halted economy. Sick, furloughed, and laid-off workforces also all contribute to diminishing worldwide manufacturing outputs. However, makers of the mechanical cables that surgical robots require are not seeing such market behavior. Momentarily more tolerant of a stopped economy, cable makers may take matters into their own hands. Increasing raw materials stocks, such as monofilaments and finished cables, for example, while remaining risky, foster opportunities for partnerships with robot makers on the basis of a shared belief that such products are necessary now more than ever.

Serving Medical Makers during a Global Emergency

Because surgical robots are still being designed, produced, and brought to market, despite the growing health crisis, cable makers are forced to innovate ways to meet evolving and often now unpredictable demand. No matter the burdens COVID-19 places upon workloads, workforces and workspaces, the mechanical cables these critical products use must be made, tested, packaged, and shipped with a totally new, and as discussed, arguably unprecedented brand of alacrity.

To achieve and maintain this unique manufacturing tempo and responsiveness, cable makers must evolve their capacities for innovation far beyond the cables themselves and into virtually every facet of the production process. Unlike more fleet-of-foot personnel, easily able to perform the full complement of their duties using little more than a laptop and cell phone, skilled mechanical cable laborers cannot. The latter use heavy machines, such as stranders, cutters, presses, and swagers.

One cannot simply relocate a fabrication workforce, along with such enormous infrastructure, even during a pandemic. The cable manufacturing process will still take place on the production floor. So, adapting production space that affords personnel safe distances to perform, while staying sensitive to increasingly restrictive and ever-changing rules for the same, is now a part of the daily grind.

Adding shifts and daily strategic planning, meant to act as incubators for constant process improvement, proliferate across the entire manufacturing progression. Employees, no matter their position on the totem pole, summon a heightened focus on producing the same world-class products, at new, fevered paces, all the while ensuring that no one is put at unnecessary risk. Now, supplanting production environments previously teeming with passionate, face-to-face collaboration, are dramatically increased physical distances between employees, the wearing of masks, and meetings held over Zoom. Like mask, glove, and ventilator makers making headlines daily, medical mechanical cable manufacturers are urgently working to stabilize schedules, create safe workspaces, and steady unpredictable demand, all in the interests of ensuring an uninterrupted supply chain for the makers of the world’s medical devices and surgical robots.

In a time of coronavirus, gone is the icy-cold notion that medical markets are merely champions of titanic revenue. Today, the mandate for smaller, stronger, and better cable is being made during the most exigent need for these surgical marvels to save the patients, the workforce, and economies for which they are built.


  1. U.S. Bureau of Labor Statistics
  2. Centers for Medicare and Medicaid Services

This article was written by Scott Dailey, Vice President of Sales and Marketing, and Greg Soja, Senior Vice President of Engineering, Carl Stahl Sava Industries, Riverdale, NJ. For more information, visit here .