Simplifying surgical power tool design with autoclavable brushless DC motors
30 November 2020
Electric motors have brought many advantages to powered hand tools. However, there are various approaches for design engineers to consider when selecting a motor for surgical instruments. Jamie Gewirtz, R&D Manager for surgical motors at Portescap, looks at some of the design challenges and discusses considerations for the selection of the most appropriate electric motor.
With manufacturers of powered surgical tools having now switched, almost universally, from pneumatic to electric operation, selecting the most appropriate electric motor has become a key design consideration. The likes of arthroscopic shavers, sagittal saws, oscillating saws, orthopaedic drills, medium- and high-speed drills, wire drivers and surgical staplers all make stringent requirements on the motor, but beyond that, there is also a need to consider sterilisation requirements.
The most common sterilisation method used in hospitals is autoclaving, also called steam sterilisation. Here, surgical hand tools are exposed to high levels of humidity, temperature and pressure for several minutes in order to render the instrument sterile. Most autoclaves have additional vacuum cycles to facilitate steam penetration and kill bacteria, viruses, fungi, and spores that can hide inside the tool.
This repeated exposure to autoclave conditions is what gives manufacturers of powered surgical instruments the most problems when it comes to electrification of the tools. So, what options are available to the designers of such tools?
With the sterilisation process so demanding, one approach is to design single-use tools that are simply disposed of after surgery. These can use an inexpensive DC motor and plastic components. However, any initial cost advantage can soon be negated, particularly for surgeries that are performed multiple times a day. Further, hospitals are becoming more proactive with green initiatives, and are looking, in particular, to reduce levels of hazardous waste.
Read the full article in the December issue of DPA
Contact Details and Archive...