blades may be purchased so that one blade is always in the sharpener. Locking blade boxes are used to store these extremely sharp blades and prevent accidental injury [1].

Once the tissue has been cut, it needs to be placed on a slide. Unfortunately, there is a tendency for frozen cuts to curl before they are placed on a glass slide. The curling can be prevented by using an anti-roll bar, or plate, and/or camel hair brushes. Camel hair brushes are also used to help orient the cut tissue sections onto the slide so that they are in perfect alignment [1]. Certain practices have found that using modern antiroll plates uniformly provides superior sections [4]. Therefore, the anti-roll plate can be used to prevent curling, and the brushes can help orient the cut tissue onto the slides. The camel hair brushes are kept in the cryochamber on a brush shelf.

In a busy Mohs practice, a backup cryostat is essential in case of unit failure. Very large specimens can be processed on one machine, while smaller specimens from several other patients can be simultaneously processed on the backup cryostat by another technician. If the ofÞce has a backup cryostat, it is important to use it regularly so that it remains operable. If two cryostats are operated adjacent to each other in the lab, the refrigeration unit exhaust from the Þrst unit must not be directly vented to the air intake of the second unit, or the second unitÕs motor could fail. If cryostat conÞguration and room space cannot prevent this problem, a custom plexiglass air diverter can change the direction of the hot exhaust airßow [1].

Preventative maintenance of cryostats is crucial to their continued functioning. The cryostatÕs moving parts should be taken apart, greased, and oiled at least quarterly. Also, before and after each cryostat use, the machine should be oiled. Maintenance logs and daily temperature logs for the cryostat should be Þlled out and kept up-to-date.

It may be less expensive in the long run to purchase a new, high-quality cryostat. An older machine can be less reliable and require more maintenance. The best strategy for selecting a cryostat is to attend a Mohs surgery or national dermatology or pathology meeting where the major cryostat manufacturers and suppliers exhibit their machines. Cost, features, and other speciÞcations of the cryostats can be easily compared to each other at these events [1].

Summary: Staining Frozen Sections

¥Manual slide staining is almost never used; automated slide staining results in better quality and is much more efÞcient.

¥Most slides are 1-mm thick, have a refractive index of 1.5, and are made of glass.

¥Fixation of tissue prevents cellular degradation throughout the staining process. Acid formalin is the most common Þxative used in most labs.

¥Hematoxylin and eosin are considered the standard for staining sections.

¥After staining, it is necessary to clear excess stain. Xylene has been the classic agent, but it is neurotoxic and ßammable.

11.7Staining Frozen Sections

Slide staining can be carried out manually or using an automatic tissue stainer. Manual staining is almost never used because it can result in an uneven quality and takes a considerable amount of time. With automated staining, there is no time penalty for the technician to prepare extra slides, which can result in fewer occurrences of incomplete margins. If slides contain large amounts of cartilage, then they should be manually run though the auto stainer; if not, the cartilage may ßoat off the slides as they advance and drop from one stain chamber to the next. Auto stainers require a water source and drain; a constant ßow of fresh water results in cleaner slides [1].

Mounting and staining supplies should be located near the staining area. Different slides are available, each with their advantages. Most slides are 1-mm thick, have a refractive index of 1.5, and are made of glass. Superfrost slides adhere tissue with a small electrostatic charge and are moderately priced. The clear and frosted slides are less expensive. Frosted slides also allow the technician to quickly determine which side is Òup,Ó assisting in preventing the technician from wiping off the wrong side of the slide and ruining a specimen that was difÞcult to cut. The frosted end may be purchased in multiple colors, and each of these colors can represent separate patients, separate Mohs

stages of each case, or may be used for other reasons [1]. It is important to note that cartilage may require adhesives for adequate attachment to the slide, such as silane and L-Lysine adhesive. Other adhesives include bovine albumin and casein glue.

Fixation of tissue is used to prevent cellular degradation throughout the staining process. Acid formalin is the most common Þxative used. Acetone is a superior Þxative to acid formalin for adipose tissue. Other tissue Þxatives include alcohol, formaldehyde, formalin, and omniÞx. Alcohol is a poor Þxative for adipose tissue, and omniÞx is used to preserve antigens for immunoperoxidase stains [4].

Hematoxylin and eosin are considered the standard for staining micrographic sections because not only do they provide superior cellular detail, they are also reasonably fast and cheap, and most histotechnologists are familiar with them. Toluidine blue O and safranin O are also dye stains that are occasionally used. Toluidine blue O stains keratinocytes and mucin, and can be 25% faster than hematoxylin and eosin, but there is still controversy concerning its use for squamous cell carcinoma [4].

After staining, it is necessary to clear excess stain. Xylene was once the classic agent, but it is neurotoxic and ßammable. Numerous xylene substitutes are available and cost more, but should be used because they are much safer. The two main classes of substitutes are D-limonene and alkanes. An aliphatic xylene is less oily and dries more quickly [4].

Cover slips are made of glass, plastic, or quartz. The plastic cover slips are cheaper, but over several years can peel from the slide. At the end of the Mohs session, they can be placed overnight in a drying oven to prevent them from sticking together when they are Þled [4].

Summary: Slide Reading

¥The microscope slide reading area can be located in the lab itself.

¥There should be little distraction when the Mohs surgeon is reading slides.

¥The table on which slides are read must be large enough for the Mohs maps, slide trays, pencils and pens, and the microscope.

11.8Slide Reading

The microscope slide reading area can be located in the lab itself if there is enough space, or can be adjacent to it. There should be little distraction while the Mohs surgeon is reading slides, and the technicians and staff should be aware of the necessity of this, especially if the reading is carried out in the lab. Special sturdy microscope tables at standard height are available for purchase. The table on which slides are read must be large enough for the Mohs maps, slide trays, pencils and pens, and the microscope. A comfortable rolling stool should be available too.

A high-quality double head microscope should be used, which allows for more than one person to analyze the slide at the same time. A lighted movable pointer is useful with the double head microscope to discuss section quality with the technician, as well as when consulting with another doctor. It should be equipped with at least a 2× objective and wide-Þeld eyepieces. The 2×, 4×, and 10× objectives will be used more than any other objectives, and therefore, an objective higher than 40× is unnecessary. Eyepieces with tilt heads are especially useful for short or tall surgeons. For those who wear glasses, the microscope can be adjusted so that the focal points of the eye pieces are a few millimeters above the surface of the eye pieces. It may also be useful to also have a dedicated pair of glasses solely for the purpose of reading slides because glasses are expensive and may become scratched, regardless [1]. Marking pens that write on glass are used for inking or dotting Þndings on the completely processed Mohs slides during reading and are available in multiple colors.

Summary: Cleaning, Sterilization,

and Maintenance of Surgical Instruments

¥Sterilizing consists of several steps which include cleaning and decontamination, packaging, loading, and storage.

¥Immediately after use, the instruments should be placed in the cleaner and soaked for at least 10 min, but for not more than a few hours because there are greater chances of corrosion.

¥The staff that handles the decontamination should wear household cleaning rubber gloves or plastic gloves for protection.

¥When packaging instruments, it is important to open all hinged instruments and disassemble all items with removable parts.

¥Steam, hot air, and chemical vapor are sterilization agents that must be able to contact the instruments for an appropriate length of time.

¥Alcoholbased autoclaves do not dull sharp instruments in the same way that steam autoclaves do, but they have a strong odor and need to be operated in well-ventilated areas.

¥Steam autoclaves are more user and environmentally friendly, but they dull sharp instruments. Also, corrosion of instruments is possible.

¥Ethylene oxide sterilization is a valuable adjunct to steam sterilization. The unit is very safe, although it may need to be exhausted to the outside to meet local and/or state regulations.

¥Sterilization is monitored with chemical and biological indicators.

¥Each sterilized package should have an expiration date written on it.

¥Instruments need to be sharpened on a regular basis.

11.9Cleaning, Sterilization,

and Maintenance of Surgical Instruments

Maintenance of the equipment begins during the surgery. During surgery, blood should be wiped from scissors and needle holders because dried blood may result in decreased capability of them to open smoothly. Also, the knife blade should be wiped frequently on a 4 × 4 pad to prevent seeding of carcinoma from the scalpel blade to uninvolved tissues being excised [1].

Sterilizing consists of several steps which include cleaning and decontamination, packaging, loading, and storage. Cleaning is important to remove residues that can interfere with the sterilization process. Generally, the instruments should be presoaked in a solution of water mixed with detergent or an enzymatic cleaner immediately after use. One way to accomplish this is by conveniently placing a small metal bin in the sink Þlled with an enzymatic cleaner. Immediately after use,

the instruments should be placed in the cleaner and allowed to soak for at least 10 min. The instruments should not be presoaked for more than a few hours because there are greater chances of corrosion. A small nylon brush is used to scrub the instruments to further clean the organic and nonorganic residue [7].

The staff that handles the decontamination should wear household cleaning rubber gloves or plastic gloves for protection against the harsh cleaners and the contaminated bodily ßuids. The eyes need to be protected with face masks, and appropriate gowns need to be worn. The staff should also use forceps to retrieve the instruments from the solution.

After the instruments have been cleaned and properly dried (reduces chances of corrosion and rupture of the package), all instruments that have movement, such as needle holders, scissors, and hemostats, are lubricated with a rust inhibitor. This solution helps to prevent compromise of the working mechanisms of these instruments. Any excess solution is wiped away using a soft cloth or surgical gauze [1]. Afterward, the instruments are ready to be packaged.

When packaging instruments, it is important to open all hinged instruments and disassemble all items with removable parts. Complex instruments should be prepared and sterilized according to the manufacturerÕs instructions. Heavy instruments should be positioned not to damage delicate ones, and those with concave surfaces should be positioned to facilitate drainage. Having the same conÞguration in each pack increases efÞcacy and saves time. ÒPeel openÓ packages are the most convenient way to package instruments, but other more rigid containers can be purchased for heavier instruments. Sterilization wraps are sometimes necessary for certain items as well. Whatever packaging is chosen, it must allow penetration of the sterilant as well as maintain sterility.

Steam, hot air, and chemical vapor are sterilization agents that must be able to contact the instruments for an appropriate length of time. In addition to allowing proper sterilant circulation, perforated trays should be placed so that the tray is parallel to the shelf, non-per- forated containers should be placed on their edge, and small items should be loosely placed in wire baskets. Peel packs should be placed on perforated or mesh bottom racks.

There are several machines used to sterilize instruments. Alcoholbased autoclaves do not dull sharp instruments in the same way that steam autoclaves do, but they have a strong odor and need to be operated in

well-ventilated areas. Also, during operation, no staff members should be in the room. Steam autoclaves are more user and environmentally friendly, but they dull sharp instruments. Also, corrosion of instruments is possible.

Ethylene oxide sterilization is a valuable adjunct to steam sterilization. Nearly anything can be ethylene oxide sterilized. It is affordable and relatively easy to install. The unit is very safe, although it may need to be exhausted to the outside to meet local and/or state regulations.

Sterilization is monitored with chemical and biological indicators. Chemical indicators are markings on pouches that change color after exposure to the sterilizing agent. They indicate that the item has been exposed to the agent, but they do not analyze for microbial kill. Therefore, routine spore testing should be done to assure that sterilization is occurring properly. Spore testing is a biological indicator used to test that sterilization is indeed effective. Spore testing should be done at least weekly. It can be assumed that if the spores are destroyed, then destruction of viruses and bacteria occurred since they are more easily inactivated.

Each sterilized package should have an expiration date written on it. Peel packages and wrapped packs sealed in 3/1,000 in. polyethylene overwrap are reported to be sterile for as long as 9 months after sterilization. If the package is wet, punctured, or torn, the instruments are no longer sterile, and they need to be repackaged and processed. Packages should be stored in a safe place, free of moisture, or possibility of contamination. Once a package becomes wet, it is not sterile anymore. Closed or covered cabinets can be a way to store the packages to prevent moisture damage. If the package falls on the ßoor, it must be examined for tears.

In addition to lubrication, instruments also need to be sharpened on a regular basis, such as scissors, curettes, and other sharp instruments. There are services which can come to the ofÞce on a regular basis to sharpen instruments.

Summary: Conclusion

¥Proper setup is important for an efÞcient, proÞtable, and safe Mohs practice.

¥The basis of a well-run ofÞce is an experienced, reliable ofÞce manager and a welltrained staff consisting of histotechnicians, medical assistants, and physician assistants and/or nurses.

11.10Conclusion

Proper setup is important for an efÞcient, proÞtable, and safe Mohs practice. The basis of a well-run ofÞce is an experienced, reliable ofÞce manager and a well-trained staff consisting of histotechnicians, medical assistants, and physician assistants and/or nurses. All staff taking direct care of patients need to be CPR certiÞed and ACLS certiÞed and trained. The operating room needs to be organized and spacious and have all the essential instruments and equipment prepared and readily available. The surgical waiting area needs to be discrete, comfortable, and in view of staff in case of an emergency. The laboratory needs to be conÞgured to allow for proper ventilation. The cryostat is an important investment and should have features that allow the histotechnicians to produce high-quality frozen sections. It should be easy to clean and needs to be maintained daily. The microscope reading area should be free of distraction. All instruments should be cleaned and sterilized appropriately. The proper setup is the basis of a successful Mohs practice.

References

1.Gross K. OfÞce and laboratory set-up and instrumentation for Mohs surgery. In: Baxter S, Gunter A, Achenbach F, editors. Mohs surgery: fundamentals and techniques. Saint Louis: Mosby; 1999. p. 15Ð55.

2. Nilsson U. The anxietyand pain-reducing effects of music interventions: a systematic review. AORN J. 2008;87(4): 780Ð807.

3. Gunson TH, Smith HR, Vinciullo C. Assessment and management of chemical exposure in the Mohs laboratory. Dermatol Surg. 2011;37:1Ð9. Epub November 11, 2010.

4. Davis DA, Pellowski DM, Hanke CW. Preparation of frozen sections. Dermatol Surg. 2004;30(12 Pt 1):1479Ð85.

5. Bakhtar O, Close A, Davidson TM, Baird SM. Tissue preparation for MOHSÕ frozen sections: a comparison of three techniques. Virchows Arch. 2007;450(5):513Ð8.

6. Desciak EB, Maloney ME. Artifacts in frozen section preparation. Dermatol Surg. 2000;26(5):500Ð4.

7. Hanke CW, Leonard AL, Reed AJ. Rapid preparation of highquality frozen sections using a membrane and vacuum system embedding machine. Dermatol Surg. 2008;34(1):20Ð5.