How often should movable parts of intruments, e.g. the hinges, be oiled?
Ideally the cleaning performance is such that all residues including the care products are removed during the cleaning process. All instruments with metal sliding surfaces should therefore be oiled after each cleaning process as recommended by the manufacturer.
Is it correct to say that pitting corrosion on surgical instruments is a locally confined process and that therefore it cannot be transfered (carried over) to other instruments by the reprocessing media?
No, active pitting corrosion can cause subsequent rusting i.e. rust carry-over. Depending on the cause, severity and extent of the pitting damage the instruments concerned should be removed from the reprocessing cycle. Such instruments should be returned to the manufacturer or a qualified repair service for reconditioning. For further information see the Red Brochure 8th Edition, Pages 55-56.
Are weld joints at surgical instruments (made of stainless steel) less corrosion-resisting and are these spots prone to increased corrodibility after frequent processing?
Products concerned of well-known instrument manufacturers do not show any difference in corrosion-resistance. This is assured by appropriate welding methods, welding parameters, and if necessary by welding filler and subsequent heat treatment improving the homogenizing of the material.
Why should instruments for eye operations be cleaned in an instrument washer/sterilizer and not manually, as in the past?
You are referring to the debate about manual reprocessing and machine reprocessing of instruments for eye operations. In principle, the method of choice should be cleaning and disinfection in automatic washers/sterilizers.
In many recommendations, leaflets and brochures, thermal disinfection methods are advocated as being superior to chemo-thermal or chemical methods. Machine cleaning and disinfection in a closed rinsing system also serves a key function by protecting members of staff. Another factor is that only machine processes can be reproduced in a sufficiently precise and validated manner that meets the requirements of the operator's regulations. The concerns of doctors and nurses on the sensitivity of instruments are no longer justified. Particularly in the case of instruments used in eye operations, baskets and perforated trays with holders ensure secure storage. Rinsing nozzles and the alignment of the rack for holding baskets and perforated trays must be arranged so that instruments are not ejected from their holders. This would be the case if standard rinsing technology for surgical instruments were used. Provided rinsing procedures and rinsing technology are used correctly, machine cleaning is gentler than manual cleaning. Aseptica 7 (3); 2001: 18-19 reports on a practical example of the reprocessing of microsurgical instruments.
Are there specific directives or guidelines on reprocessing surgical needles? Should surgical needles be reprocessed in cleaning and disinfection machines and are there specific holding devices? How are these materials checked and maintained?
As far as we know, manufacturers use different materials for reusable needles. A coarse distinction is made between needles made of corrosion-resistant high-alloy steel and needles made of low-alloy (i.e. non-corrosion resistant) steel coated with an electroplated protection layer. In principle, both types can be reprocessed in automatic washers/sterilizers using programs certified for surgical instruments made of stainless steel. pH-neutral or mildly alkaline reprocessing is particularly suitable for chrome-plated needles and other chrome-plated instruments. The needles must be held in suitable containers during reprocessing so they cannot be lost in the washer/sterilizer compartment. The needle boxes provided by the manufacturers are particularly suitable for this purpose and they also ensure adequate cleaning. As well as checking whether the instruments have been cleaned sufficiently, chrome-plated/nickel-plated needles in particular require thorough checking for surface integrity. This is best done using a magnifying glass. If the needle is chrome-plated or nickel-plated the chrome or nickel forms a protective surface layer on the substrate designed mainly to make the instrument corrosion-resistant. This layer, however, will always have microcracks. Extended cracks will form over time as a result of mechanical loads. Such parts with prior damage are subjected to additional attack during reprocessing because the chemicals used in the cleaning process may also get underneath the surface layer and react with the substrate to form corrosion products. Needles damaged in this way must be segregated and discarded in order to protect other instruments. There is a risk of transferring rust to other uncorroded instruments (secondary corrosion). The number of reprocessing cycles is therefore linked to surface integrity. Needle boxes can be used for cleaning, sterilization and storage of the needles at the point of use. During routine use, rubber-coated magnetic plates have proved effective for passing needles to the surgeon at the point of use. After cleaning in an automatic machine (w/d) the needles are fixed on these plates while the perforated tray is loaded.
Are the following specifications on reprocessing ophthalmic instruments (use in Laser surgery) given by the manufacturer sufficient, or is the disinfection step missing? "Clean all instruments in filtered and softened water enriched with Palmolive (1:100)
(Re)processing steps are defined for (re)processing surgical instruments and hence for ophthalmic instruments. A coarse distinction is made between manual and machine cleaning in the process of disinfection and cleaning. Because this question is based on a manual procedure we only propose to comment on the manual procedure. If manual cleaning is specified, the instruments used undergo wet preparation for (re)processing. This involves immersion/soaking in a disinfection bath. This treatment is required to protect staff health (see UVV = accident prevention regulation). The disinfectant used for this purpose must be certified for surgical instruments. Approved combined disinfecting and cleaning agent can also be used. Mixtures of cleaning agent and disinfectant made up in-house are not permissible as this may impair the effectiveness of disinfection. A product designed to remove typical residues (that is tissues, body fluids, blood, proteins etc.) must be used to clean surgical instruments. Domestic cleaning agents are not suitable for (re)processing surgical instruments. Drinking water can be used for cleaning. Toothbrushes are ideal for cleaning purposes. Fully demineralized water is recommended for final rinsing (the term "filtered" is not specific enough). Fully demineralized water does not contain lime (hardness) or other salts or ingredients. Rinsing must ensure that any residues, both organic and cleaning agent and disinfectant residues are removed. Instruments must be dry prior to sterilization. Drying with compressed air is particularly gentle and effective.
Is it sufficient to immerse the surgical instruments in a disinfectant solution specified by the manufacturer in order to use these instruments on other patients? Isn't it necessary to sterilize these instruments each time?
Instruments used in invasive surgery must be sterilized after reprocessing. A steam sterilization procedure in accordance with EN285 must be used for steam-sterilizable instruments to achieve this. Thermally unstable instruments must be subjected to a low-temperature sterilization procedure in conformity with the manufacturer's instructions. Make sure you also observe the RKI (Robert Koch Institute) recommendations on reprocessing medical devices published in November 2001. These instructions can be downloaded under www.rki.de.
Is there a risk that instruments made of stainless steel loose their usage property when being reprocessed?
Is there any literature or other information on the corrosion of laser lettering on instruments?
Laser labelling is a procedure used for identifying medical instruments. Etching is the conventional method of marking and identifying instruments and laser labelling must also be clearly visible and resistant to standard conditions of use and (re)processing. Provided correct procedures are used for laser labelling, none of the letters will corrode. Corrosion of laser labelling is usually due to insufficient guidelines or faulty procedures in the labelling process. We are not aware of any literature on this issue. At this point, however, we should also like to point out that any factor triggering or promoting corrosion such as contact with water containing high amounts of minerals or salts should be excluded during reprocessing.
Can the hardness of a surgical instrument (surface layer and core) change after repeated sterilization cycles? Is the hardness of a surgical instrument the same throughout the instrument?
Is the hardness of a surgical instrument the same throughout the instrument?
Answer: This depends on the heat treatment during the hardening process.
The hardness of quality instruments is homogenous.