• concept
• five lean principles
• kaizen
• lean thinking
• surgical process
• value assets

The term "lean production" identifies a production methodology that aims to minimize waste and, in principle, eliminate it. The history of the organization and management of production systems has its roots in very remote times, indicatively it coincides with 1903 as "year zero", when the entrepreneur Henry Ford had the revolutionary idea of ​​creating a car for every family. The Ford T introduced on the market in 1908 was a great success, so much so that over the years more than 15,007,033 pieces have been produced. Considering that mass production had established itself at a time when no one owned a car, it was possible to create demand and consequently make the most of the growth of this new market. All this until the early 1970s, when the level of growth was almost zero. From this moment on, mass production slowly began its decline, this stagnant situation could have continued indefinitely if in the meantime a new automotive industry had not been born in Japan. The Japanese were not trying to simply replicate the now antiquated American manufacturing system, but were developing an entirely new manufacturing approach, what we now call "lean manufacturing." This methodology known as "lean production" was therefore born in Japan, specifically within Sakichi Toyoda's Toyota factory. An indispensable concept to define the Lean philosophy is "Just in Time", with this term it indicates "having available exactly what is needed, in the exact place where it is needed, at the exact moment in which it is needed and in the right quantities". Lean philosophy is also based on 5 principles contained within a pyramid, from the base to the top we have: value, value stream map, continuous flow, pull and perfection. In the perspective of the Lean philosophy, waste means any activity that does not create value, we refer to "3M" that is: mura (irregularities), walls (overload) and muda (waste). The concept of "muda" can then be divided into macro-classes based on the nature and characteristics that identify, Taiichi Ohno differentiates seven categories of waste: overproduction, waiting, transportation, process, inventory, movements and defects.
Through the application of various tools such as A3 report, takt time, cell design, kanban and one piece flow, it is possible to make the most of the use of the lean philosophy in the healthcare sector. Specifically, thanks to this study, the results of the application of the lean approach in surgical processes can be highlighted.