A thorough curettage using ring curettes (Thiemann, New York, USA) is performed under local anesthesia (mepivacaine-adrenaline 10 mg/ml + 5 μg/ml). At first, a large curette (no.3) is used to remove the bulk of the tumor and then a medium-sized one (no.2), and finally a small curette (no.1) is used to remove any extensions of the malignancy. The curettage material is also sent for histopathological examination, and sometimes the findings are more aggressive than the original one [35]. After meticulous curettage, the tumor is often found to have wider lateral extension and greater depth than expected, and one has to be particularly thorough when treating malignancies in the nasolabial folds, in the inner canthi, and in the pre- and postauricular sulci. The curettage is performed according to the technique described by Strum and Leider [32]. Sometimes undermined edges have to be cut off by a pair of scissors. A cotton stick dipped in 50 % iron chloride solution is used for hemostasis.

Freezing is carried out with a maximal continuous spraying of liquid nitrogen (−196 °C) using a handheld Cry-Ac (Brymill Corp., New York, USA) with the nozzle held as horizontally as possible and, in general, with the patient sitting. By using the vertical position, the problem of liquid nitrogen flowing on the lesion is avoided, and the spraying becomes more standardized. The tumor area is most often, especially on flat surfaces, demarcated by a neoprene cone of appropriate size. The spray tip, size B, is moved in circular motions over the treatment zone, at about 1 cm distance, until the lateral spread of freeze has reached a minimum of 5 mm outside the tumor border or 1–1.5 mm outside the neoprene cone. The skin is always well fixed to the underlying bone by the freezing in spite of the “ballooning” of the local anesthesia. For tumors overlying cartilage on the nasal ala or the pinna of the ear, the freezing continues until the opposing side is frozen.

The goal of the freezing is a fast cooling rate and a slow thawing rate [5]. The procedure is always repeated a second time.

On a special tumor chart registration of the freeze time (10–25 s, depending on the tumor size), the lateral spread of freeze (≥5 mm), the halo thaw time (at least 60 s), and the complete thaw time (2–5 min) are done but no thermocouples are employed. A therapeutic sequence of curettage-cryosurgery of a clinically ill-defined BCC on ala nasi is seen in Fig. 18.4a–e. The same procedure of a BCC on the dorsal aspect of an ear is seen in Fig. 18.5a–e. All treatments are performed at a single outpatient visit.

It is important to be aware of and inform the patient about the usual and expected postoperative tissue response. Written information about this is handed over to the patient. The incidence of complications is low. They may be classified as temporary or permanent. Pain during and immediately after cryosurgery is common. It may be quite intense but it is usually transient. Edema, especially periorbital, is also very common. However, infection rarely occurs. Of the permanent complications, the most common is hypopigmentation. Retraction of tissue and tissue defects as notching of ala nasi may be seen after treatment of tumors overriding the rim of ala. Notching of the ears may occur after treatment of malignancies overreaching the helix. Other complications are rare [34, 36].