Which Metals Are Commonly Used for Surgical Instruments? - Materials and Engineering Resources - Matmatch (2022)

By

MDMarta Danylenko

on April 6, 2018

There are many different considerations when choosing a material to use in the medical industry. After all, the wrong material choice could lead to disastrous consequences. In this article, we take a look at which metals are used for surgical instruments, and why.

The most common metals used for surgical instruments are:

  • Stainless steel
  • Titanium
  • Tantalum
  • Platinium
  • Palladium

Read on to learn why these metals were chosen. The metals used for surgical instruments have to adhere to strict criteria.

Mechanical Properties

We know that different metals have very different properties. Finding the best properties to suit the needs of each type of surgical equipment is vital. Some of the issue to consider include:-

(Video) Materialism Podcast Ep 9. Materials That Remember

Ductility and malleability

The metal must be relatively malleable so it can be shaped without causing flaws. However, it must not be too malleable as it will need to hold its shape once manufactured. Depending on the instrument/application, the metal used may also need to be fairly ductile. Many surgical instruments are long and thin, e.g. scalpels, forceps, scissors, etc. They should not break off during the operation. The lowest modulus required for surgical instruments is 100GPa.

Ability to withstand high temperatures

Surgical instruments are subjected to elevated temperatures during the sterilisation process. The instruments are sterilised by scolding hot steam at a minimum of 121 degree Celsius temperature for at least 30 minutes. There should be minimum dimensional change in the instrument after repeated sterilisations.

Wear and tear

Surgeons require instruments that perform correctly every time they are used. Wear and tear affects surgical instruments as after a certain usage they will not perform as required. For example scissors may become blunt and not cut tissue easily.

Resistance to corrosion

Surgical instruments are increasingly exposed to bodily fluids, tap water and cleansers. Bodily fluids such as blood or pus generally contain chloride ions, which can corrode the instruments. They are also washed under the tap water to remove bodily fluids from them. The water may contain high concentration of minerals such as chlorine, sodium and magnesium. These can cause severe stains and corrosion if left to sit on the instruments. Hospitals generally use distilled water to partly eliminate the problem.

Various cleansers are used to clean the instruments from bacteria and infections. They could be either an alkaline solution or an acidic solutions with varying pH. This acidic/alkaline solutions may, over time, corrode the surgical instruments.

Biocompatibility

In simple terms, biocompatibility is a material’s compatibility with living tissue. Biocompatible materials do not produce a toxic or immunological response when exposed to the body or bodily fluids. Elements such as nickel, chromium, and cobalt are likely to cause allergic and tissue hypersensitivity problems.

Magnetic Properties

Surgical instruments are sometimes subjected to a magnetic field in the operating room such as a from an MRI, which generates a magnetic field of ~1.5 Tesla. This magnetic field can affect surgical instruments in numerous ways including:-

  • Unwanted movement caused by the magnetic field interactions (i.e. the missile effect)
  • Heating of instruments because of radio frequency (RF) power deposition
  • Artifacts associated with the use of the instrument

Non-magnetic instruments such as stainless steel, titanium alloys etc are recommended in such environments.

Glare

By anodizing the surgical instruments, manufacturers change the surface properties of the metal. This makes the surgical instrumentsnon-reflective.When the surgeon/lab operators are working under operating lights or a microscope, an anti-glare surface is important.

Ergonomics

Lightweight surgical instrument are simply easier to handle, especially during long surgical procedures, dissections or when performing repetitive tasks. This means that titanium surgical tools are more suitable than their stainless steel counterparts.

When it comes to biomedical instruments, not all metals are up to the job, especially base metals. In fact, most surgical instruments are made from metal alloys. Stainless steel has traditionally been the metal alloy of choice, but there are alternatives when necessary.

Which Metals Are Commonly Used for Surgical Instruments? - Materials and Engineering Resources - Matmatch (1)

Stainless steel grades for surgicalinstruments

Stainless steel (sometimes referred to as inox steel) is one of the most commonly used metal alloys in the manufacture of surgical implements.

Austenitic 316 steel is a type of stainless steel used often, and is referred to as “surgical steel”. This is because it is a tough metal that is very resistant to corrosion. It is also used frequently in the chemical industry.

AISI 301 is the most commonly used metal for manufacturing springs which are useful in medical instruments. It gains mechanical strength when cold-worked, but loses corrosion resistance.

Stainless steel can withstand temperatures as high as 400°C, meaning it can be sterilised easily in an autoclave at 180°C. It also has the benefit of being almost as tough and hard-wearing as carbon steel.

Interested in stainless steel? Then read this article – everything about stainless steel, its composition, categories, and applications.

Titanium in surgical tools

Titanium alloy has only recently started being used as a material for surgical instruments, taking off in the 1960s.

The most obvious benefit of titanium is its superior strength. Its tensile strength is almost the same as carbon steel and it is 100% corrosion resistant. Despite its overall strength, it is more flexible than stainless steel and is approximately 40% lighter.

Read more about technologies and materials enabling surgical tools and biomedical implants. The article is written by an expert in the field – the Doctor of Medicine, Hugo Herrero Antón de Vez.

Titanium is perfect for both surgical instruments and implants, as it is biocompatible and has the intrinsic quality that it fuses well with human bones. For this reason, it has become the metal of choice for orthopaedic rods, pins, plates, and dental implants.

Titanium is more resistant to heat than stainless steel, withstanding up to 430°C, and it expands and contracts less when heated and cooled.

Depending on the properties required for the instrument, Titanium Grade 1 or 2 can be machined, welded, and hot or cold-worked quite easily, so it is a versatile metal too.

Overall, titanium is a tough, durable metal that has become a common material used for all kinds of medical purposes.

https://youtu.be/G5qmIxssmQw

Tantalum in orthopaedics

Tantalum, a refractory metal, is strong, ductile and has a very high melting point (3017°C). But for the medical industry, its most attractive benefit is its high biocompatibility.

The metal is immune to bodily fluids, and is also highly corrosion-resistant, so it can be used in surgery without causing adverse effects. For the same reasons, it’s also used for implants and bone replacement material in prostheses.

Its ductility is also an attractive property, as it can be drawn into thin wire, while its malleability allows it to be easily fabricated into various shapes.

Which Metals Are Commonly Used for Surgical Instruments? - Materials and Engineering Resources - Matmatch (2)

Platinum and palladium in medicine

Although platinum and palladium are expensive precious metals, they have similar properties that make them uniquely suited to certain surgical applications.

Firstly, they can both be easily formed into a variety of shapes as they are highly malleable and ductile, meaning you can easily make rolls, sheets, tubes, wires, etc. They are especially useful for intricate parts, ideal for precision surgical instruments.

Both platinum and palladium are highly corrosion resistant and inert, so they won’t cause problems when in contact with the body or internal organs.

One of the major uses in recent years has been creating ultra-thin wires that surgeons use to guide and position implants such as catheters and stents.

Another advantage is that both platinum and palladium show up very clearly on X-ray making them ideal to be used as markers on implants.

They are both strong, durable metals. The only real differences between the two are density, mass, melting points, and price, with palladium being the cheaper of the two.

Aluminium for parts and cases

Certain instrument parts and cases are manufactured fromaluminium, which is lightweight. Aluminium is treated with an electrochemical process called anodization which forms an oxide layer on the surface of the aluminium. The oxide layer offers great corrosion resistance. Certain cleaners, disinfectant solutions and abrasive brushes can damage the protective layer.

Tungsten Carbide

Tungsten carbide (TC) is classed as a carbide, which you’ll find in the overall group of ceramics, but we thought it worth a mention in this article too. It is composed of tungsten and carbon atoms, and is used in the manufacture of various instruments. These include:

  • Needle holders
  • Scissors
  • Pin cutters
  • Pliers
  • Wire tighteners

Since tungsten carbide is harder than steel, it offers exceptional durability. Usually, the TC is soldered or welded to the jaws/working ends of instruments. TC inserts that are soldered can be separated from the instrument and replaced.

Surgical instrument metals

Hopefully, this article has given you some idea of the different types of metal used to make surgical instruments and their properties.

As you have seen, the different varieties of stainless steel are the most popular as they are relatively cheap, plentiful, and practical for most applications.

Titanium is the next most common, as it has additional strength and is ideal for orthopaedic implants due to the fact it fuses easily with bone.

Tantalum’s properties make it an ideal choice to use in surgical instruments.

Finally, there are the precious metals, platinum, and palladium. These are the most expensive, which is why they are rarely used in a medical setting, but they are ideal for small, precision implements and parts.

FAQs

What type of alloy is the most suitable for producing surgical implants? ›

They are made of austenitic 316 steel commonly known as “surgical steel” or “marine grade steel.” Stainless steel, also known as Inox (from the French word "inoxydable"), is highly corrosion resistant and it is a common choice of material for biomedical implants or body piercing jewelry.

Is stainless steel 440? ›

440 steel is part of the stainless steels or those alloy steels which contain a minimum of 10% chromium, imbuing these alloys with increased resistance to corrosion.

What is titanium and its uses? ›

Titanium is as strong as steel but much less dense. It is therefore important as an alloying agent with many metals including aluminium, molybdenum and iron. These alloys are mainly used in aircraft, spacecraft and missiles because of their low density and ability to withstand extremes of temperature.

What are the four types of steel? ›

The Four Types of Steel
  • Carbon Steels. Carbon steels only contain trace amounts of elements besides carbon and iron. ...
  • Alloy Steels. Alloy steels are created by adding additional alloying elements like nickel, copper, chromium, and/or aluminum. ...
  • Stainless Steels.
Nov 3, 2021

What type of metal is used in surgery? ›

Stainless steel (sometimes referred to as inox steel) is one of the most commonly used metal alloys in the manufacture of surgical implements. Austenitic 316 steel is a type of stainless steel used often, and is referred to as “surgical steel”. This is because it is a tough metal that is very resistant to corrosion.

What are the metals used in surgeries? ›

The most commonly used metals in surgery are surgical stainless steel and titanium. Surgical stainless steel is a term used to label particular grades of stainless steel that are commonly used in biomedical appliances.

What is 400 series stainless steel used for? ›

The 400 series of stainless steels have a higher carbon content, giving it a martensitic crystalline structure that provides the end product with high-strength and high-wear resistance. The 400 series steels tend to be used in agricultural equipment, gas turbine exhaust silencers, hardware, motor shafts, and more.

Is 440A good steel? ›

440C Steel: This steel has a carbon content range between . 95% to 1.20% and is generally considered higher-end steel. It's prevalent in knives because it provides a good mixture of hardness and corrosion resistance and isn't terribly expensive.

What is type 430 stainless steel? ›

Type 430 is a ferritic stainless steel with corrosion resistance approaching that of 304/304L stainless steel. This grade does not work harden rapidly and can be formed using both mild stretch forming, bending, or drawing operations.

Is titanium a type of steel? ›

Titanium is considered to be a strong metal with an ultimate tensile strength of 434 MPa that makes 63,000 psi which is roughly equal to the strength of a low-grade steel alloy. This means titanium can be used as a replacement for steel—a major benefit, as it is 45% lighter than steel.

What is cobalt used for? ›

Cobalt is commonly used in electroplating because of its appearance, hardness, and resistance to oxidation. Cobalt compounds have been used for centuries to create a rich blue color in glass, glazes, ceramics, porcelain, pottery, tiles, and enamels.

What are 3 common uses of titanium? ›

Titanium is a familiar metal. Many people know that it is used in jewelry, prosthetics, tennis rackets, goalie masks, scissors, bicycle frames, surgical tools, mobile phones and other high-performance products. Titanium is as strong as steel but weights about half as much.

What are the five classes of steel? ›

The Four Main Types of Steel
  • Carbon Steel. Carbon steel looks dull, matte-like, and is known to be vulnerable to corrosion. ...
  • Alloy Steel. Next up is alloy steel, which is a mixture of several different metals, like nickel, copper, and aluminum. ...
  • Tool Steel. ...
  • Stainless Steel.

Is steel stronger than iron? ›

Steel is stronger than iron (yield and ultimate tensile strength) and tougher than many types of iron as well (often measured as fracture toughness). The most common types of steel have additions of less than . 5% carbon by weight.

Why are metals used for surgical tools? ›

Surgical grade stainless steel

Stainless steel has been the metal of choice for surgical instruments for decades, not only due to its strength and corrosion-resistance, but also because it is easy to clean, making it ideal for environments where hygiene is a priority.

What materials are used for surgical instruments? ›

Surgical instruments are generally made of carbon steel, stainless steel, aluminum, or titanium, and are available in a range of sizes.

Which steel is used for surgical instruments? ›

Surgical stainless steel is a grade of stainless steel used in biomedical applications. The most common "surgical steels" are austenitic SAE 316 stainless and martensitic SAE 440, SAE 420, and 17-4 stainless steels.

What alloy is surgical steel? ›

Surgical stainless steel is an iron-based alloy containing chromium, nickel, molybdenum, and small quantities of carbon. The 316L (F-56 according to ASTM) is the most commonly used form of stainless steel for orthopedic applications.

What metal is used for medical implants? ›

Metal-Containing Implants

The most common metals and alloys used in implants include stainless steel, cobalt-chrome alloy, titanium, and nickel-titanium alloy (nitinol). Other metals, such as gold, platinum, silver, iridium, tantalum, and tungsten, are also common in many medical devices.

What materials are used for surgical instruments? ›

Surgical instruments are generally made of carbon steel, stainless steel, aluminum, or titanium, and are available in a range of sizes.

What type of finish is used on most surgical instruments? ›

Surgical instruments; this area of the medical industry tends to like satin finishes that are smooth, but non-reflective. As you can imagine when a person is in the operating room the last thing that is needed is shiny objects that may distract or reflect into the surgeons' eyes.

Why are metals used for surgical tools? ›

Surgical grade stainless steel

Stainless steel has been the metal of choice for surgical instruments for decades, not only due to its strength and corrosion-resistance, but also because it is easy to clean, making it ideal for environments where hygiene is a priority.

Which steel is used for surgical instruments? ›

Surgical stainless steel is a grade of stainless steel used in biomedical applications. The most common "surgical steels" are austenitic SAE 316 stainless and martensitic SAE 440, SAE 420, and 17-4 stainless steels.

Which of the following alloys is used in preparing surgical instruments Mcq? ›

Uses of stainless steel :

It is used for making surgical instruments.

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