Surgical instruments have been around for thousands of years. Ancient people used to make surgical instruments from bones, ivory or stones and used them to take out foreign materials from wounds. In the classical age, metals such as bronze, gold, steel and nickel were used for the manufacturing of surgical instruments. Today, however, stainless steel is used for the production of surgical instruments.
Understanding how these instruments are made would help you know your instruments better and would also help you in identifying the cause of any weaknesses in the instrument design.
- RAW MATERIAL:
Knowledge regarding different types of metals used for the making of surgical instruments is important if you wish to know which instrument is to be used for which purpose. Majorly, there are two types of metals that are used for the manufacturing of surgical instruments:
- Stainless Steel:
The stainless steel used for surgical instruments is of two types. 1) 300 series stainless steel, also known as Austenitic stainless steel. This is mostly used in retractors. 2) 400 series stainless steel, also called Martensitic stainless steel, which is mostly used for needles, scissors and other instruments that undergo additional stress during their operation.
- Tungsten Carbide:
It is a very strong and durable metal, most commonly used in needle holders or the cutting edges of scissors.
- MANUFACTURING PROCESS:
The manufacturing process of surgical instruments is not a long and complicated one, yet it is performed by very skilled and experienced persons and many of the steps require direct handling of the material.
The metal is heated to a point where it becomes soft, after which a rough outline of the desired instrument is forged on the metal..
After a rough shape of the instrument is made, the excess metal is trimmed out to get a more perfect shape of the instrument.
This involves further trimming of the material as well as the introduction of special shapes like teeth, serrations, etc. This process is not completed in a single step but is repeated several times until the instrument attains its desired shape.
- Heat Treatment:
This step is performed in order to change the physical properties of the material. There are three types of treatments. A material may either be given one type of treatment or more than one types of treatment, depending on the desired end-product. These types are 1) Hardening (for hardening the material), 2) Annealing (for softening the material) and 3) Tempering (for strengthening the material).
- Chemical Treatment:
This treatment is performed in order to clean the instruments and to make them corrosion-resistant. The instruments that are not properly treated at that stage are more prone to corrosion. This treatment includes 1) Passivation (to remove free iron, rust or iron particles from the material by using nitric acid and sodium dichromate) and 2) Pickling (to remove scale formed on the material due to oxidation by using dilute sulphuric or nitric acid).
- Fixing and Polishing:
After chemical treatment, the instruments are aligned in their working order and polished to give them a smooth and satin finish that is comfortable to hold and is resistant to corrosion.
- Etching and Packaging:
Important identifying information is etched upon the instrument using either chemical methods, physical methods or laser. After that the instruments are sent for final inspection before they are eventually packaged and shipped off to their final destination.