Microsurgical instruments

Our ophthalmic OR is going to be furnished with new surgical instruments. In the past, newly acquired instruments were initially sent through three washing and sterilization cycles before using them on patients for the first time. However, the manufacture

How many initial washing cycles are required primarily depends on the efficiency of your cleaning system and the degree of "contamination". The task is to remove any oil, dust and the like from the instruments' surfaces. So if your existing procedures have so far ensured satisfactory results, we recommend you to stick to them.See also Red Brochure (8th edition), "How to treat brand-new and repaired instruments", page 1.

Which disinfectant detergents can be used to clean (before disinfection) semicritical and critical instruments of group A (manual application in the ophthalmological practice)?

For critical instruments of group A, detergents with a cleaning effect and non-protein-fixing treatment agents are used prior to disinfection, which meet the requirements for medical devices class 1 (detergent) or 2a (disinfectant). The cleaning product used can be equipped with or without antimicrobial effect. If a product is used which does not have an anti-microbial effect, personnel protection must be ensured with suitable measures (protective clothing). In general, therefore, any cleaning product, combined cleaning and disinfecting product or cleaning product with disinfectant activity recommended for this purpose by the manufacturer and which is a medical device may be used. It is important that products are used here whose ingredients do not cause protein fixation and thus make cleaning and subsequent disinfection more difficult. Such ingredients are e.g. antimicrobial agents from the group of aldehydes and alcohols, so that the use of disinfectants containing aldehydes and alcohols is not recommended for this purpose. When selecting a detergent with disinfectant action, care must also be taken to ensure that at least one bactericidal and limited virucidal activity is present under the conditions of use. In this way, personnel protection, which is the main concern in this case, can be ensured. In general, the manufacturer's instructions regarding concentration, temperature and exposure time must be strictly observed when using the cleaning and disinfecting agents. The AKI recommends using freshly prepared solutions every day, which should be changed more frequently if necessary in the case of heavy contamination. When carrying out cleaning or disinfectant cleaning, care must be taken to ensure that above all English instruments, such as tubes and cannulas, as well as instruments with cavities are continuous and also have contact with the cleaning and disinfectant solution from the inside. After cleaning, the instruments must always be rinsed with sufficiently clear running water to prevent detergent residues from being carried over into the subsequent disinfection bath. This also removes any dirt that may still be adhering.

How is the alkaline instrument reprocessing of ophthalmic instruments to be answered in connection with the RKI communication "The variant of Creutzfeldt-Jakob disease"?

Basically, ophthalmic instruments should be subjected to mechanical alkaline cleaning, since eyes are among the vCJD risk material. However, since alkaline residues may remain on and in particular in instruments that could endanger the patient, a pH-neutral mechanical or standardized manual reprocessing can be used as an alternative. In this context, it is important to ensure good cleaning performance of the products and subsequent steam sterilization at 134 °C with a holding time of 18 min.

Why should used ophthalmic surgical instruments be cleaned in an instrument dishwasher? Can't they be cleaned by hand, as used to be the case?

They refer to discussions regarding the manual or mechanical reprocessing of eye surgery instruments. In principle, mechanical methods of cleaning and disinfection should be preferred today. Many recommendations and leaflets call for the preference of thermal over chemo-thermal and chemical methods of disinfection. Mechanical cleaning and disinfection in a closed rinsing system also serves essentially to protect personnel. Also, only mechanical methods are reproducible in a comprehensible, exact and validated manner, thus meeting the requirements of the operator ordinance. The concern of doctors and nursing staff about the sensitive instruments is no longer justified today. Especially for the instruments of the eye surgery there are baskets and sieve trays with holders in which they are safely stored. The rinsing mechanism of the trolley for holding the baskets and sieve trays must be aligned in such a way that the instruments are not ejected from the holders, which would be the case with the usual rinsing technique for surgical instruments. If the rinsing method and technique are used correctly, mechanical cleaning is more gentle than manual cleaning. In aseptica 7 (3); 2001: 18-19 a practical example of the reprocessing of microsurgical instruments is reported.

What are the preparation steps for ophthalmic instruments?

There are defined reprocessing steps for surgical instruments and thus also for ophthalmological instruments (see also Robert Koch guideline). For disinfection/cleaning, a rough distinction can be made between manual and mechanical reprocessing. Since the present text suggests a manual procedure, we would like to comment only on this at this point. If manual cleaning is intended, the used instruments are "wet deposited". This means treatment in a disinfectant bath. Such treatment is carried out for reasons of personal health protection (see UVV). The disinfectant used for this purpose must be approved for surgical instruments in order to prevent material damage. A released, combined disinfectant and cleaning agent can also be used for this purpose. Own mixtures of cleaner and disinfectant are not permitted, as the disinfection effect can be negatively influenced.

How do you estimate the risk during the reprocessing of eye surgery instruments with regard to a possible carry-over of acids? Can these - even after sterilization - cause irritation of the eye?

Taking into account the RKI notice "The variant of Creutzfeldt-Jakob disease", published in the Federal Health Gazette April 2002, ophthalmic instruments should be reprocessed mechanically using an alkaline cleaning procedure (pH value > 10, 55 °C, 10 min exposure time) and then steam sterilized for 5 min at 134 °C. However, if users or surgeons fear that alkaline cleaning agents will not be completely rinsed from or to eye instruments, a pH-neutral, possibly enzymatic cleaning process can also be carried out, but then the final steam sterilization at 134 °C with a contact time of 18 min must be carried out. When reprocessing by machine, it must of course be ensured that both alkaline cleaners and neutralizing agents used in the first rinse cycle, as well as neutral cleaning agents, are rinsed off the inner and outer surfaces of the ophthalmic instruments without leaving any residue.

When reprocessing ophthalmic instruments, is a pH value of 5 in the last rinse cycle still acceptable or should it be at pH 7 as a matter of course?

According to the information available to us, a pH value of 5 is acceptable. Fully demineralised water (without any additives) already has this pH value in some cases. According to information from doctors, alkaline additives (pH > 7) are undesirable. Carryover from previous rinses into the last rinse cycle must be avoided. If additives are dispensed in the last rinse cycle, it is essential to clarify their suitability for instruments used by ophthalmologists with the manufacturer of the product dispensed.

Does the reprocessing of minimally invasive surgical instruments have to be done in a machine? What is the legal basis, recommendations. I am a hygiene officer and so far I only have the recommendations of the RKI or MDD § 4. What other laws/recommendations are available?

Apart from the recommendations you mentioned and the Operator Ordinance, there are no laws in Germany requiring automated reprocessing. However, the RKI recommendation is anchored in the MPBetreibV (Operator Ordinance) and hence has the character of a law.

To what extent must the individual components of separable, composite instruments be disassembled for sterilisation and reassembled again before use?

In principle, the manufacturer's instructions must be observed. It also depends on which steam sterilisation method is used. For example, modular MIS forceps can be sterilised in the assembled state using the fractioned pre-vacuum process, but it must be ensured that the screw joint is opened by at least one turn. If the same forceps are sterilised with the flow method, these must be disassembled. Rubber caps should be removed, but should be stored together with the instrument during sterilisation for ease of reassembling. If an item is modified in the CSSD - even cutting to size is a modification - the conformity issued by the manufacturer is questionable.

Do unused MIS instruments have to be disassembled and reassembled for mechanical cleaning or is it sufficient to simply place them in a tray? How are lumens then dried?

Instruments that have not been used, but where recontamination cannot be reliably ruled out, must be reprocessed in the same way as used instruments. All dismantlable instruments must be taken apart according to manufacturers' instructions and - very importantly - connected to the machine in such a way that water accesses all internal and external surfaces. This means that all lumens must be connected as this is the only way to ensure adequate irrigation. By connecting the instruments, better drying effect is also achieved.