Six Degrees of Freedom can Boost Minimally Invasive Surgical Techniques

This article was recently published by Medical Design and Outsourcing and written by Garrett Plank. He discussed the Ultra-fine wire-winding techniques that enable sensor data acquisition via new angular 6DOF technology. Find the original article here:

Six Degrees of Freedom Can Boost Minimally Invasive Surgical Techniques

Minimally invasive surgical procedures require advanced motion tracking technology that can locate surgical instruments and tools inside the human body when there is no clear line of sight. Electromagnetic tracking (EMT) technology enables this performance: Electromagnetic coils drive the “six degrees of freedom,” known as 6DOF, that empower surgeons and clinicians to clearly visualize and navigate the human body. Today, advancements in electromagnetics are increasing 6DOF accuracy without increasing the size of the device. Where 6DOF traditionally required two different coils wound separately, a new angular method of ultra-fine wire-winding allows device manufacturers to employ angled coil configurations to deliver highly precise 6DOF sensor data. These angled coil configurations are designed to deliver the same or better procedural accuracy than what is delivered by the traditional solution. Expect expanded use of them in very small surgical and therapeutic devices.

Reflecting the diversity of medical design, it’s possible to use 6DOF advances as a sensor ready to integrate into a manufacturer’s device — or as a complete navigation system that includes the tracking platform, sensors, and surgical navigation instruments. This is creating a path to an even greater slate of minimally invasive treatment options – helping surgeons reach further and deeper into the human body while patients benefit from reduced risk and shorter recoveries.

6DOF is a measurement reference to a device’s capability for accuracy, based on multiple axes across which the device can move. (A greater number of degrees of freedom equates to a greater capacity for precision movement.) In electromagnetic solutions, coils wound with ultra-fine wire enable navigation through a 3D view of a patient’s anatomy; by moving across 2/3 separate x, y, and z axes, they operate as sensors for acquiring spatial location and orientation data within the human body. Hidden within a given surgical device or tool, these electromagnetic coils power surgical navigation by transmitting data in real-time, to enable on-screen images that guide surgeons.

Manufacturers wind the electromagnetic coils with wire about one-tenth the diameter of a human hair. Ultra-fine wire-winding techniques incorporate film insulated copper magnet wire, for example, from AWG 45 (.0018 in.) to AWG 60 (.0003 in.), enabling miniaturization for a slate of advanced devices and applications. Angular 6DOF takes this potential even further, placing the wire at a defined angle to the coil axis. The design improves the signal intensity and aids in the reduction of the number and size of coils — driving smaller devices that can reach more critical areas such as the heart, brain, and lungs with less surgical trauma. As medical practitioners can access more of the human anatomy with highly precise 6DOF tracking and visualization, patient care and recovery improve in step.

Next-gen electromagnetics reduce complexity in sensor integration

Manufacturers and health providers favor electromagnetic tracking is favored because of its accuracy, low cost and reliability. At the same time, it’s an area ripe for innovation – as many of today’s EMT systems were designed decades ago, long before some modern advanced procedures even existed and seamless integration was not as critical.

“Electromagnetics design demands a specialized engineering skillset, one not necessarily found at the heart of the typical medical device development team,” said Andrew Brown, cofounder and CEO of Radwave Technologies, a provider of customizable, next-generation electromagnetic tracking platforms. “A robust electromagnetic tracking system must navigate the entire procedure space to accurately locate medical instruments that are out of line-ofsight and perform seamlessly with existing medical equipment. It’s no easy feat, yet it is a crucial part of the device design process, particularly as the industry continually works to remove risk, reduce costs, and accelerate development.”

Technologies used to accurately place surgical instruments are numerous and complex – including impedance and optical tracking, robotic information, or intraprocedural imaging options such as fluoroscopy, computed tomography (CT or CAT scans), cone-beam computed tomography systems (CBCT), ultrasound and more. It’s critically important to positive patient outcomes that these complex technologies work well with each other to provide accurate instrument placement. For example, systems must provide tracking information while ensuring distortion-free intraprocedural imaging.

Improving patient care with sensor science

Considering the complexity of procedures and technologies at play, strategies for sensor deployment may be as critical as the sensor choice itself. “Along with advances in sensor precision and accuracy, the medtech market has begun to recognize the need to improve and 3/3 streamline developer access to electromagnetics technology at both the sensor and system level,” added Brown. “Ideally, configurable EMT systems can access the value of 6DOF advances, tracking medical instruments over the entire patient’s volume while also providing robust detection of electromagnetic interference with high positional accuracy.”

6DOF sensors — offering increased precision and accuracy based on advanced wire-winding techniques — are compatible with a range of intraoperative imaging technologies with minimal image artifacts. Placed within medical devices, on tools, or used as position references, they provide accurate knowledge of locations and orientations when surgical and therapeutic instruments are out of line-of-sight. As the use of minimally invasive surgery continues to grow, 6DOF advancements play a crucial role in extending minimally invasive techniques to new applications enabled by smaller, more precise devices. 


About the Author

Garret Plank

Business Development | Medical | Sales

Garrett supports TT Electronics’ global business development featuring innovative solutions for surgical navigation, active implantable devices, and therapeutic and diagnostic medical equipment.

Connect with Garrett at or LinkedIn

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