How Surgical Instruments Are Sterilized: Step-by-Step Guide


One of the most important procedures in any surgical or clinical environment is the sterilization of surgical equipment. Sterilization ensures that all reusable surgical equipment is free from microorganisms, thereby eliminating the risk of infection and ensuring patient safety. 

In this article, we will discuss in-depth, step-by-step procedures for sterilizing surgical equipment, best practices, types of sterilization, and considerations that healthcare providers must adhere to.

Why Sterilization Is So Important in Surgery

Before going through the process, it's necessary to know the "why" of sterilization:

  • Prevents post-operative infections
  • Reduces cross-contamination risk
  • Ensures patient safety and confidence
  • Complies with healthcare regulations and standards
  • Keeps instrument functionality and lifespan intact

Step-by-Step Guide to Sterilizing Surgical Instruments

1. Pre-Cleaning Immediately After Use

The moment a surgical procedure is complete, instruments must be cleaned right away to prevent blood and debris from drying and hardening.

Pre-cleaning steps:

  • Rinse under warm running water.
  • An enzymatic spray or gel is to be used to inhibit the drying of dirt.
  • Keep sensitive or sharp instruments separate from the rest so as not to cause damage when being cleaned.

2. Manual Cleaning or Ultrasonic Cleaning

Prior to sterilization, any loose debris that is visible has to be cleared by either manual or mechanical means.

Manual Cleaning:

  • Scrub hinges, joints, and grooves using a soft brush.
  • Pretreat with pH-neutral surgical instrument detergent.
  • Rinse thoroughly using deionized or distilled water.

Ultrasonic Cleaning

  • Instruments are submerged in an ultrasonic cleaner containing cleaning solution.
  • High-frequency sound waves dislodge microscopic particles from surfaces.
  • Perfect for intricate instruments with difficult-to-reach areas.

Tips:

  • Leave hinged instruments in the open position.
  • Don't mix metals to avoid galvanic reactions.

3. Rinsing and Drying

Detergent or water left behind can lead to corrosion or staining if not adequately removed.

Rinsing tips:

  • Use deionized water to prevent mineral deposits.
  • Use lint-free cloths or compressed air for drying.

Proper drying is essential to guarantee the effectiveness of the sterilization process and avoid rusting.

4. Inspection and Maintenance

Every instrument should be examined thoroughly prior to sterilization to verify it is clean and operational.

Check for:

  • Cracks, corrosion, or loose hinges
  • Sharpness of cutting edges
  • Alignment of jaws or tips

Use surgical-grade lubricant (also referred to as "instrument milk") on hinged instruments to retain mobility and extend lifespan.

5. Packaging and Wrapping

Surgical instruments need to be wrapped or packaged prior to sterilization in order to maintain sterility until they are used.

Standard packaging choices:

  • Color-coded sterilization pouches
  • Rigid containers for heavy sets
  • Wraps or towels for heavy instrument kits

Labeling requirements:

  • Date of sterilization
  • Load number
  • Staff member's name or initials

6. Sterilization Techniques

There are several methods of sterilization employed in medical and surgical settings. The process varies with the material and the use of the surgical instruments.

1: Steam Sterilization (Autoclaving)

Most standard and efficient for heat-resistant devices.

  • Temperature: 121–134°C (250–273°F)
  • Time: 15–30 minutes (dependent on load and equipment)
  • Pressure: 15–30 psi
2: Ethylene Oxide (EtO) Gas Sterilization
  • Apply to heat- or moisture-sensitive devices.
  • It requires a longer cycle (up to 16 hours with aeration)
  • High bactericidal and virucidal activity, particularly against spores
3: Hydrogen Peroxide Plasma (Low-Temperature Sterilization)
  • Inert and suitable for fragile equipment
  • Reduced cycle time (30–75 minutes)
  • No toxic residue
4: Dry Heat Sterilization
  • Never used but quite effective for water-sensitive products.
  • High temperature (160–180°C) for 2+ hours
7. Storage After Sterilization

Sterilization is preserved by proper storage until the instruments are put to use.

Best practices:

  • Store in clean, dry cabinets
  • Avoid high-humidity environments
  • Follow "first in, first out" rotation
  • Reinspect the packaging before use

Best Practices for Sterilizing Surgical Instruments

  • Always use the manufacturer's instructions for cleaning and sterilization.
  • Do not overload autoclaves or sterilizers.
  • Regularly perform biological, chemical, and mechanical monitoring.
  • Maintain records of sterilization cycles for accountability and traceability.
  • Train all staff who work on instrument reprocessing.

What Happens If Instrument’s Sterilization Is Improper?

If sterilization is improper, the following can occur:

  • Hospital-acquired infections (HAIs)
  • Patient complications
  • Legal and regulatory penalties
  • Increased healthcare costs
  • Damage or corrosion to costly instruments

Common Mistakes to Avoid While Sterilization

  • Tap water for rinsing instruments.
  • Omitting pre-cleaning procedures.
  • Overloading sterilization trays.
  • Failing to dry instruments thoroughly.
  • Storing sterilized packs in damp or dirty areas.

Final Thoughts

Surgical instrument sterilization is not optional in ensuring a clean and safe healthcare environment. Every step, from pre-cleaning to storage, counts in preventing infections and achieving positive patient outcomes. Through stringent compliance with procedures, medical professionals can ensure the effectiveness and durability of their surgical instruments, as well as maintain the best quality of care.

FAQs

How often should surgical instruments be sterilized?

Reusable surgical instruments must be sterilized after every use, regardless of their appearance. Even minute contaminants may be harmful.

Are all surgical instruments sterilizable by the same process?

No. The process varies based on material, design, and the manufacturer's instructions. Heat-sensitive instruments need low-temperature options such as EtO or hydrogen peroxide plasma.

What is the difference between disinfection and sterilization?

A: Disinfection lowers the microbial load but does not destroy all spores, whereas sterilization kills all types of microbial life, including spores and viruses.