Instrumentation

Instrumentation

Definition

Instrumentology in the medical context deals with the identification, classification and proper handling of medical instruments. These instruments, which are used for curative and surgical purposes, are made of various materials that are suitable for reprocessing.

Differentiation according to different classifications

Instruments can be differentiated according to different classifications:

• by function: e.g. cutting, holding, grasping, spreading
• by name: e.g. the Metzenbaum scissors are named after the American surgeon Dr. Myron Firth Metzenbaum
• by property: surgical forceps, anatomical forceps, sharp hook

Example:

Within these classifications, there are other criteria to differentiate instruments, such as instruments with a golden handle that have a hard metal insert.

Note on reprocessing

Maintaining the high quality of instruments depends largely on careful maintenance, thorough care and professional reprocessing. These aspects are crucial to ensuring the longevity and reliability of instruments and preserving their value over time.Instrument cycle

Before new instruments are integrated into the instrument cycle, they must be washed at least three times. This promotes the value-preserving build-up of the so-called passive layer.

Storage of instruments

• Before the procedure, after the sterilization process

  In order to ensure 100% reprocessing, it is strongly recommended that instruments are stored, cleaned, disinfected and sterilized in individual storage systems. These can be sieve trays with spacers or rubber mats or even a special storage system in which the instruments are gently fixed or even have their own rinsing connection.

  In addition, such storage systems protect against mechanical damage during the entire instrument cycle. Proper storage is essential for preserving the value of the instruments and contributes to extending the instrument life cycle. In addition, there are cost savings for unnecessary repair or replacement costs.

  One example is microsurgery, as only delicate instruments are used in this specialist field. As a general rule, sterilized medical devices should always be stored in a clean and dry environment.

   

• After the procedure, during the reprocessing process

  In order to maintain the value of the medical devices in the long term and to prevent biological material such as blood and tissue from drying, immediate pre-cleaning is necessary.

  After pre-cleaning, the instruments should be opened/disassembled and returned to their storage systems for transportation to the AEMP (reprocessing unit for medical devices) in order to prevent mechanical damage and to store the instruments until further processing.

  In addition, contaminated medical devices should not be left standing for too long to prevent them from drying out and forming corrosion.

  Extended standing times can promote damage to the instrument surface and the so-called passive layer, as deposits promote corrosion and silicates and other deposits can no longer be removed during the reprocessing process. The damage can therefore be irreparable. A premature new purchase, which leads to an unplanned budget burden, is the result of improper storage and storage of instruments.

  During the reprocessing process, it is crucial to store medical devices in the appropriate storage systems. During the cleaning and disinfection processes, the instruments must be stored in such a way that thorough rinsing is guaranteed. Once this process has been completed and the medical devices have been inspected and cared for in between, sterilization takes place, during which the instruments continue to be stored in the storage systems (trays). For this purpose, the trays are placed in special steam-permeable sterile packaging to ensure the effectiveness of the sterilization process.

Risk assessment of instruments

Medical devices used on patients must be correctly classified in terms of risk in order to determine the appropriate reprocessing procedure. This classification is done by assessing the area of contact of the device with the patient and the complexity of the device.

The assessment is based on two main criteria:

1. Classification according to area of application

   The first classification is based on the area of application of the instrument. This classification only takes into account the contact area and not the design of the instrument. The categories are structured as follows:

   • non-critical: Medical devices in this category only come into contact with intact skin without penetrating it, e.g. stethoscope, ECG electrodes
   • semicritical: Instruments in this category come into contact with mucous membranes or altered skin, but do not penetrate them, e.g. proctoscope, specula
   • Critical: This category includes instruments that penetrate the skin or mucous membrane and come into contact with tissue and organs. This includes piercing and cutting instruments as well as instruments that touch open wounds. E.g. scissors, scalpels and needle holders. Sterile reprocessing is required for these instruments.
2. Classification according to design

   The differentiation according to design and material properties only applies to semi-critical and critical instruments. Non-critical medical devices do not fall under this classification. For instruments in the semi-critical and critical categories, it must be determined whether they are medical devices with a simple design and smooth surfaces. These are assigned to classification A.

   However, if there are areas that are difficult to access, such as narrow cavities, complex joints or screw threads, classification B should be applied.

Special features of medical devices:

In instrumentology, there are various categories of medical devices, each of which has specific features and requirements. Three important categories are thermolabile instruments, multi-part instruments and single-use instruments. Each of these groups has special requirements for handling and use in everyday medical practice.

1. Thermolabile instruments
   Thermolabile instruments are particularly sensitive to high temperatures. These include, for example, certain endoscopes and optical devices. These instruments must not be reprocessed using conventional methods such as steam sterilization, as the high temperatures can damage the material. Instead, alternative methods such as low-temperature plasma sterilization are used without damaging the sensitive materials.

    

2. Dissectable instruments
   Dissectable instruments consist of several components that must be disassembled before cleaning and disinfection to ensure that all surfaces can be thoroughly cleaned and disinfected.

    

   Examples of multi-part instruments:

   • Punching
   • Rongeurs

   Disassembling these instruments enables effective cleaning and helps to minimize the risk of infection. After cleaning and before sterilization, the parts must be carefully dried and reassembled.

    

3. Disposable instruments
   Disposable instruments are intended for single use and are disposed of after use. They offer numerous advantages, particularly in terms of hygiene, as the risk of cross-contamination is eliminated. These instruments are clearly identifiable and marked with a crossed-out 2.

    

   Examples of disposable instruments:    

   • Disposable scalpel blades
   • Disposable scissors and forceps

   Disposable instruments eliminate the need for time-consuming reprocessing and reduce the workload for medical staff. However, they are not always economical or environmentally friendly, especially when used frequently. In addition, they cannot always compete with reusable instruments in terms of precision and quality.