Control and precision are vital in surgical equipment: Powered devices are helping

In the UK there are over 4.3 million people waiting for an operation, with research showing that the number of surgeries required per year is continually increasing. Despite hacksaws and scalpels being reliable surgical tools, the growing number of procedures on the table means that surgeons require tools that offer high levels of control and precision time and time again.

The increase in the number of surgeries is also having a negative effect on the wellbeing of surgeons. Longer periods of time spent in the operating theatre is leading to medical professionals, especially surgeons, developing painful back, neck and wrist conditions. These conditions can shorten careers. Therefore, keeping surgeons healthy is a top priority.

Powered medical devices offer an avenue to reduce the strain on surgeons by giving them tools to make surgeries more precise and less strenuous on their bodies. Each different type of medical device has some benefit for surgeons, in fact, there are many different types of powered medical devices from bone saws to cast removers. For the most part, these tools are grouped either by their power source, shape or application.

There are three main methods of powering surgical tools; batteries, mains electricity and pneumatics. Most modern designs are moving away from pneumatics and concentrating more on electrical options. This is because battery and electrically powered designs are more compact and electrical motors can give more controlled actuation, which is vital for precise operations like surgery.

Battery designs can be incredibly versatile because they don't need wires and are not limited in their range of motion. However, batteries do not last forever and due to the length of certain complex operations battery powered tools are not always adequate.

Shape is an important factor for medical tools. There are two main shapes used for powered surgical devices — gun grip and pencil grip. The shape changes the way that the tool is held, meaning it directly influences the way that the tool is designed.

Pencil grips are more precise and are best suited for more delicate surgical tools. They are also less bulky letting the operator get closer to the patient. Gun grips, on the other hand, offer the holder a stronger grip on the tool giving greater control.

As many of these surgical tools have limited space, the shape also dictates the type of drive system that can be used in the design.

Drive systems in handheld medical devices are especially important. Due to the limited space, the drive must have a high-power density and it must provide

constant steady actuation while remaining small and lightweight. At the same time, they must also be quiet and have low levels of vibration. Only if a drive system can offer all these qualities can powered surgical tools reach the desired standards of performance.

For example, the Faulhaber BHx 1645 & 1660 brushless motor series is designed specifically for use in handheld powered devices. As such, it has a long thin design with a high-power density. The motors are offered in two lengths making them ideal for either pencil or gun grips making them suitable for most types of precision tool designs and can provide high-quality actuation in many surgical applications.

The main two applications for powered surgical tools are sawing and drilling. Powered sawing is the more common application of the two, specifically when it comes to cutting bones. There are three main types of saw cutting motions oscillating, reciprocating and sagittal. Each of these types of saw has a specific area for which it is best suited.

Powered drilling applications have a large variety of uses from dental to reconstructive surgeries. They are used to drill holes in which pins, plates and screws can be fixed or they can be used to remove decaying teeth in preparation of fillings. Accurate drilling is therefore central to successful surgeries.

Precise surgical powered tools are becoming more integral to the success of modern-day surgeries. With the number of operations being carried out, it is crucial that our medical professionals are equipped with high-quality medical devices, rather than the classical surgical implements of yesteryear.

It’s clear, then, that motion control is already changing medical procedures and has the capacity to transform them. It is estimated that by 2022, the motion control market will be worth $22.84 billion. And that robotics will form the next wave of motion systems – predicted to be worth $23.9 billion by itself in 2022.

The medical industry has specific requirements for robotics and motion control applications, especially the ability to achieve precise control. The use of motion systems in medicine includes bionic prosthetics, wheelchairs that can traverse stairs and rough terrain, air pumps for respiratory needs, transplanted mechanical valves and microsurgery instruments.

John Johnston, NPI director, Chemigraphic, says: "All devices are trending toward being smaller, more compact, easier to carry and store. Yet motion control devices for the medical market are often designed for precise applications where size really is at a premium."

Miniature ball screws, motorised linear actuators, motorised lead screws, and linear bearings are increasingly being chosen for use in smaller-scale applications.

"In addition, electromechanical actuators can now replace the pumps, compressors, delivery systems, and other space-consuming technology essential for hydraulic and pneumatic actuation while internal electronics increasingly eliminate complex wiring, connecting to power sources and communications networks with just a few wires," Johnston adds.

"Particularly in the medical market, demand for faster delivery of more personalised equipment is on the increase. Effective prototyping is important to many solutions because designers typically must try various component options before settling on the one that best suits the application."

Again, this is where advanced modelling technology, such as 3D metal-based printers and simulation software, give designers more flexibility and greater speed.

Automation also plays a key role in personalising or customising products.Automated processes allow EMS partners to switch from high-speed and high-volume production to agile systems that can seamlessly alter manufacturing product types without the need to stop the line.

Emerging production technologies, from computerised-numerical-control (CNC) cutting to 3D printing, bypass the need for tool changes, also make it possible to produce batches of one.

Customisation – and increasingly personalisation – of patient-specific devices will require high quality, high mix production that is perfectly suited to the application of IoT tech, machine learning and automation.